3 

NASA Contractor Report 1 8 1 7 2 6 

i 

ADVANCED PILOTED AIRCRAFT FLIGHT 

CONTROL SYSTEM DESIGN METHODOLOGY 

VOLUME II: THE FCX FLIGHT CONTROL 

DESIGN EXPERT SYSTEM 

(HA SA-CR- 18 1726 -Vol-2) BUY ANCED PILOT ED N89-26014 

AUCRAPT PLIGHT CONTROL SYSTEH DESlGN 

HETHODOLOGP, VOLUME 2: THE PCX PLIGHT 

CONTROL DESIGN EXPEHT SYSTEH Final Report U ncla s 

(Systems Technology) 190 p CSCL 01C G3/08 0222711' 

Thomas T. Myers and Duane T. McRuer 

Systems Technology, Inc. 

Hawthorne, CA 90250 

Contract No. NASI -1 7987 

October 1988 

National Aeronautics and 

Space Administration 

. 

Langley Research Center 

Hampton, Virginia 23665-5225 
PRECEDING PAGE BLANK NOT FILMED 

TABLE OF CONTENTS ! 

Page 

A. OVERVIEW OF FCX ............................................. 1 

B. LEVEL5 EXPERT SYSTEM SHELL .................................. 4 

C. PROGRAM CC .................................................. 5 

D. STRUCTURE OF THE FCX EXPERT SYST ............................ 7 

E. GLOBAL DATA STRUCTURES ...................................... 8 

F. FCX KNOWLEDGE BASES ......................................... 10 

G. UTILITY PROGRAMS ............................................ 30 

H. PROGRAM CC MACROS ........................................... 33 

I. INSTALLATION OF THE FCX SOFTWARE ............................ 35 

J. INITIATING A FCX SESSION .................................... 35 

REFERENCES ...................................................... 38 

APPENDIX A. .FCX FLIGHT CONTROL DESIGN EXPERT SYSTEM 

KNOWLEDGE BASE LISTINGS ............................ 39 

LIST OF FIGURES 

PaFe 

1. Knowledge Base Structure in the FCX Flight 

Control Expert System ....................................... 11 

2. FCX Main Menu ............................................... 12 

3. Aircraft Basic Data File, "ACDATA.PRM" ...................... 13 

4. Flight Condition and Trim File, "FLTCOND.PRM" ............... 15 

5. Stability and Control Derivatives File, DERIVS .............. 16 

6. Bare Airframe Model ......................................... 17 

7. Transfer Function File for Input to LEVEL 5, GFCX ........... 20 

8. Open Loop Aircraft .......................................... 21 

9. Yaw Damper Diagram Showing Roll and 

Yaw Rate Blending Coefficients .............................. 25 

10. Augmented Aircraft System Model ............................ 27 

.I 

TR-1228-1-11 

iii w4_I(,IwtlyIwCIy~ 
LIST OF TABLES 

Page + 

1. Include Files and Knowledge Bases in C:\FCSXPRT ............. 36 

2. Utilities and Macros in C:\STI .............................. 36 

4 

i.17 
n 

VOLUME I1 

THE FCX FLIGHT CONTROL DESIGN EXPERT SYSTEM 

A. OVERVIEW OF FCX 

. 

While the overall effort of this project has been to develop and 

refine a particular flight control system design methodology, a major 

thrust has been improved implementation of these methods in software. 

Here the primary focus has been on ways of extending traditional computeraided control system design (CACSD) software by exploiting recent developments in "knowledge-based" concepts, specifically expert systems. Algorithmic CACSD software has been used in flight control system design for 

many years and in fact this application has been a major driver in the 

development of many "in-house" and commercial packages. Software support 

for both classical and modern control system design methods is available, 

but modern (in particular optimal control) approaches have received the 

most development. In fact modern control theory has been largely shaped 

to exploit what digital computers and procedural programming languages do 

best which has resulted in a great many sophisticated and powerful analysis and design tools. While new developments continue to appear in 

algorithmic CACSD (e.g., recent work in singular value based robust MIMO 

design methods) this line of effort has reached a certain level of 

maturity . 

Recently new developments in computer science, in particular artificial intelligence, have created the possibility of attacking aspects of 

flight control design which have not been well served by algorithmic 

CACSD. The evolution of modern control and its implementation in software 

has lead to increasing generality and abstraction. While this creates a 

"powerful" methodology in the sense that a given algorithim can be applied 

to control systems arising in many disciplines, this generality is gained 

at the cost of a certain loss of information important in "real-world" 

design. By way of illustration, the numerical state space model used in 

an optimal control design of an FCS is not immediately distinguishable 

from matrices that might arise in a nuclear powerplant design. But to 

aircraft control system designers the physical distinctions of the plant 

TR-1228-1-11 1 
are obvious and of great practical importance. To an FCS designer working under deadlines on a new aircraft, the knowledge that his design 

methods could be applied to many other disciplines is of only academic 

interest. On the other hand that designer would have great interest in 

any approaches specific to his problem. Thus the potential for combining 

application specific support with the power of general algorithmic CACSD 

design tools is the primary promise of expert systems for design. This 

potential arises from the fact that expert system concepts were developed 

specifically for highly empirical disciplines (e.g., medical diagnosis, 

geological prospecting, etc.) where the deterministic mathematical models 

which allow generality and abstraction are very limited. 

What has emerged from this project is that algorithmic CACSD is and 

will continue to be an essential tool in flight control system design. 

However, expert system software can complement (as opposed to replace) the 

algorithmic tools by facilitating development of more application specific 

software. This is the perspective from which the FCX Flight Control 

Design software package was developed in this project. This package 

"federates" two basic components: an expert system and an algorithmic 

computer-aided control system design (CACSD) program. .The 'expert system - 

has been developed in this project using the expert system "shell" program 

LEVEL5 by Information Builders Inc. The CACSD program is STI's Program 

CC Version 3 with extensions developed in this project. The expert system 

ordinarily acts as the intermediary between the human user and Program CC 

although the later can of course be used directly. 

h The FCX expert system as presently developed is only a limited prototype capable of supporting basic lateral-directional FCS design activities 

related to the design example used in the project. FCX presently supports 

design of only one FCS architecture (yaw damper plus roll damper) and the 

rules are largely focused on Class IV (highly maneuverable) aircraft. 

Despite this limited scope, the major elements which appear necessary for 

application of knowledge-based software concepts to flight control design 

have been assembled and thus FCX represents a prototype which can be 

tested, critiqued and evolved in an ongoing process of development. 

TR-1228-1-11 2 
t 

The fundamental problem solving paradigm on which FCX is based is a 

form of "generate and test" (Ref. 5). The basic procedure is to generate 

one or more FCS architectures which are then defined in sufficient detail 

to be tested against the appropriate requirements and specifications for 

the aircraft and flight condition. The primary role of the FCS design 

heuristics captured in the FCX production rules, is to insure that the 

designs most likely to be successful are tried first. "Most likely" is 

determined by long experience with the specific flight control architectures about which FCX has knowledge. This builds in a certain conservatism to FCX, but ultimately does not preclude unconventional designs if 

the traditional designs fail to satisfy the requirements. 

This last point is related to and dependant on a somewhat broader 

principle that has emerged in this work as essential for expert design 

systems such as FCX. That is, such knowledge-based design tools should, 

whenever feasible, allow the user to decide what is to be at each step. 

Only when the user indicates that he or she does not know what to do 

should the system use its innate design knowledge to propose the next step 

or the next parameter value. FCX accommodates this principle and provides 

valuable service to the user in either role. To accomplish this, FCX 

functions at two levels: first as a natural language interface for 

Program CC and secondly as a FCS design expert system. 

When the user specifies an action (by making a selection from a menu 

or providing a numerical value of a parameter), FCX acts as an "intelligent gofer" and handles the detail work in setting up appropriate models, 

issuing commands to Program CC, etc. In this role FCX appears as a discipline- specific natural language interface -- i.e., the user can speak 

to FCX in flight control jargon (e.g., "yaw damper", "rate gyro tilt 

angle") without having to learn the Program CC command language. This 

capability is essential to making the system of use to experienced flight 

control designers as well as novices. This latter point is very important because we believe that. if expert design systems are to be of real 

value they must be truly useful to journeymen designers not just apprentices. 

TR-1228-1-11 3 
When and if the user reaches a step in the design process using FCX 

where he cannot make a decision when prompted, he has the option of 

replying "unknown" at which point FCX will search its rule base in an 

effort to make the decision or set a parameter value. At this point FCX 

actually operates as a true expert system. At the present state of 

development of FCX, most of the design heuristics necessary to support 

this mode reside in only a few of the many FCX knowledge bases. The rules 

in the other knowledge bases primarily support the natural language interface and are typically involved in collection of aircraft and flight condition data and transfer of data to and from Program CC. The distinction 

between the natural language interface elements and the design expert 

elements will be discussed further in connection with specific knowledge 

bases. 

d 

k 

To put the FCX development into perspective it is useful to compare 

it to the few other applications of expert systems to CACSD so far 

reported (e.g., Refs. 6 and 7). Generally other proposals and developments appear to put more emphasis on modern and optimal control procedures 

whereas FCX emphasizes classical. approaches. Consequently the other 

developments have a more general, more abstract focus than does FCX and 

thus put more emphasis on the expert system as an interface for algorithmic CACSD. The distinguishing features of this approach is that the knowledge imbedded in the expert system is knowledge about algorithms and 

operation of CACSD software rather than knowledge about aircraft characteristics and FCS design practice as is emphasized in FCX. We believe 

that the FCX implementation built on the aircraft-centered approach and 

classical control methods emphasized in this project comes closer to the 

spirit and potential of the expert system concept -- namely to take 

advantage of specialized information about specific systems. 

B. LEVEL5 EXPERT SYSTEM SHELL 

The FCX flight control design expert system element has been developed in the LEVEL5 expert system development "shell" from LEVEL5 

Research, Indialantic, Florida a subsidiary of Information Builders, Inc. 

LEVELS, version 1.0 for IBM-PC and compatible personnel computers has been 

TR-1228-1-11 4 
used for this development (Ref. 1). Despite the name change, LEVEL5 is 

merely the latest version of the INSIGHT 2 expert system which has been 

used throughout the project. LEVEL5 is also available for Apple 

McIntosh, DEC/VAX and IBM mainframe computers. Since the basic (uncompiled) form of LEVEL5 knowledge bases are ASCII files (called "PRL" 

files), the FCX expert system can be transferred to and run on any of 

these computers after recompiling (however, Program CC, is presently 

available only for IBM-PC class personal computers.) 

The original motivation for using an expert system shell, such as 

LEVELS, in this project, was to minimize the effort in implementation and 

thus keep the focus more on the flight control knowledge base development 

rather than the "knowledge engineering" (software design) aspects. The 

promise of commercial expert system shells, which were just becoming 

available for personal computers as the project began, was that experts 

could implement their expert systems without the assistance of specially 

trained knowledge engineers. It does appear that use of the shell 

avoided, or at least postponed, some of the effort that would have been 

expended in this project if the implementation had been done in AI 

languages such as LISP or PROLOG. Rather than eliminating the need for 

knowledge engineering capability, it is probably more accurate to say that 

the use of shells allow experts to begin implementation of their expert 

systems as they learn basic knowledge engineering principles. The LEVEL5 

shell does impose certain limitations and constraints, that would not have 

arisen using LISP or PROLOG. But the limitations of LEVEL5 have been 

reasonable and have not seriously limited the initial development of the 

FCX at a prototype level and in fact effectively restricted the scope of 

the initial development to a manageable task. Other commercial expert 

system shells contain features and capabilities which eliminate these 

restrictions and provide a route to further development of FCX. 

C. PROGRAM CC 

The algorithmic CACSD element incorporated in the FCX system is STI's 

Program CC Version 3 which is documented in Ref. 2. The FCX LEVEL5 

expert system acts as a natural language interface between the user and 

TR-1228-1-11 5 
Program CC. These LEVELS-Program CC links have been mechanized by using 

the LEVEL5 "ACTIVATE" capability which allows external programs to be run 

from within a LEVEL5 knowledge base. Program CC is activated from many 

rules within the FCX knowledge bases. When an operation is completed in 

Program CC, control is returned to the calling knowledge base which continues processing rules using facts returned from Program CC. Among the 

basic operations performed by Program CC are construction of state space 

models of the bare airframe and FCS loops, generation of transfer function 

matrices and generation of on screen graphics such as Bode and root locus 

4 

plots. 

The execution by Program CC of specialized operations required by the 

FCX expert system is made possible by use of the Program CC "macro" capability. A Program CC macro is a series of commands which can be executed 

in sequence at any time by invoking the macro name as a pseudo-command. 

Macros may contain parameters which are specified (from calculations in a 

knowledge base) when the macro is invoked. Thus the FCX package includes 

a number of macros which perform operations such as defining the bare 

airframe transfer function matrix from a state space model setup in the 

FCX FLTCOND expert. 

Several extensions have been made to Program CC Version 3 as part of 

this project. A command called "SIGGY" has been added to generate Bodesiggy root locus plots. The SFREQ command has been added to perform 

singular value based robustness calculations for multi-input multi-output 

problems. These additional commands are documented in Ref. 2. Some additional extensions have been made to Program CC to facilitate the interface 

with LEVELS. LEVEL5 has special features for passing data to and from 

programs in several languages, but not BASIC in which Program CC is written. Thus some auxiliary programs have been written to pass data by reading files generated by LEVEL5 and converting them to Program CC compatible format and vice versa. This allows LEVEL5 to transmit not only 

numerical data but also Program CC macro names. 

An advanced version, Version 4, of Program CC is now being marketed 

by STI (Ref. 3 and 4). Version 4 has all of the capabilities of Version 3 

including Bode-siggy root locus and singular value robustness methods but 

TR-1228-1-11 6 
~- 

I 

with many improvements in these plus many new methods and commands. 

Version 4 also has a command line feature that streamlines interfacing 

with other software such as LEVELS. Unfortunately, the RAM memory 

requirements are sufficiently higher for this advanced version so that it 

can not be used with LEVELS. This is due to the intrinsically high 

memory requirements of LEVEL5. However the capabilities of Program CC 

Version 3 are more than adequate to support the present level of development of FCX. 

D. STRUCTURE OF THE FCX EXPERT SYSTEM 

The FCX flight control design expert system is a collection of 18 

chained LEVEL5 knowledge bases which act as group of "consulting 

experts". Each expert has knowledge of a quite limited area of flight 

control design such as definition of requirements for the given aircraft 

and flight condition or yaw damper design. While these software experts 

mimic the capability of expert human FCS designers, they are much more 

limited in their scope (and certainly .their capability and knowledge) than 

a human design expert. 

The division of responsibility among the experts is logically related 

to the design procedures of Sec I through IV, but the actual scope of each 

knowledge base is determined primarily by software design considerations. 

Primary among these software considerations is the need to minimize the 

difficulty of testing and validation by limiting the size of each chained 

knowledge base. This consideration is analogous to the accepted practice 

of using small modular subroutines in structured programming in procedural 

languages. However, the expert system environment has some inherent 

features which make it easier to test individual experts in isolation. 

Testing subroutines in isolation often requires time-consuming development 

of special files or loading programs. However any of the experts developed in LEVEL5 can be interrogated in isolation and, when facts that would 

ordinarily be provided by another knowledge base are required, the expert 

simply formulates an appropriately phrased question to the user. 

TR-1228-1-11 7 
E. GLOBAL DATA STRUCTURES 

Before the individual FCX knowledge bases are discussed, some global 

data structures that are used in common by all knowledge bases will be . explained. These appear as a special type of LEVEL5 file called an 

"include" file. Include files are used to incorporate the same data 

elements in several chained knowledge bases without having to include 

redundant text in many PRL (ASCII knowledge base) files. An include file 

is included in a LEVEL5 knowledge base during compilation whenever the 

file name (preceded by at'$") is encountered in the .PRL file. 

a. Shared Facts File 

Whenever facts are to be used in more than one LEVEL5 chained knowledge base, they must be declared as "shared" facts in each knowledge 

base. This declaration takes the form of a list of the facts specifying 

the fact type (simplefact, numeric, attribute-value or string) of each. 

This shared facts list is analogous to common blocks used in FORTRAN programs and, like common blocks, it is essential that the shared facts list 

be exactly the same in each knowledge base. This is routinely handled in 

LEVEL5 by making the shared facts list an include file with the name 

SHAREFCT.SHR. 

Strictly speaking not all facts need to be included in the shared 

facts list; However,' it became apparent early in the development of FCX 

that it was very advantageous to include all facts in the list along with 

comments indicating the modules in which the facts were originally 

defined. This list grew very rapidly and became a focal point of development of FCX. In effect the shared facts list becomes the vocabularv of 

FCX and teaching the expert system an adequate vocabulary of flight control system design became one of the most time consuming and important 

parts of the development. This concern with the vocabulary of FCS design 

and the syntax of facts (and syntactical limitations in LEVEL5) are distinguishing characteristics of the expert system development compared to 

traditional algorithmic CACSD software in procedural languages. Specifically there is more concern with grammar (including vocabulary, syntax and 

semantics) in the former as opposed to a concern with variables, equations 

TR-1228-1-11 8 
a 

and algorithms in the latter. In retrospect, this seems reasonable for a 

software environment (the expert system) which attempts to deal with those 

heuristics which have traditionally been easier to state qualitatively in 

English than quantitatively in mathematical expressions. This implies a 

more practical role for natural-language interfaces in CACSD software than 

was earlier realized. In particular as noted above the important role 

that FCX can play for the journeyman FCS designer, apart from providing 

FCS design recommendations, is to interface with the algorithmic software 

(i.e., Program CC) in the language of aircraft dynamics and flight control 

systems rather than the generic command language of Program CC. 

b. Multi-Valued Attributes File 

Attribute-value fact types are the most complex syntactical forms in 

LEVEL5 and are useful in reducing the number of questions the user must 

be asked to establish a fact. Ordinarily this comes about because LEVEL5 

assumes that an attribute has only one true value. For example if the 

"Aircraft Classification" attribute is known to have the value "Class IV" 

the user does not have to be asked if the value is Class I, I1 or I11 

because FCX knows these are mutually exclusive values. This makes the 

expert system appear more intelligent at a common sense level. However, 

it is quite possible for certain attributes to have more than one value 

simultaneously. For example the "Yaw damper measurement" attribute can 

include both yaw rate and roll rate. This is provided for in LEVEL5 by 

using the MULTI control element selector. To insure that all knowledge 

bases treat attribute-value pairs the same, the MULTI declaration is 

included in each PRL knowledge base file. For convenience and consistency 

the MULTI declaration has been placed in an include file called MULTI.SHR. 

c. Exhaustive Evaluation of SimDlefacts 

LEVEL5 provides a control element selector for simplefacts, called 

EXHAUSTIVE, which is analogous to the MULTI selector for attribute-value 

pairs. Enabling the EXHAUSTIVE control element causes the inference 

engine to evaluate all possible rules which can conclude a fact rather 

than stopping when the fact has been verified. Many simplefacts state 

TR-1228-1-11 9 
that a certain action has been taken and are often placed in goal outlines 

to drive the design and assessment processes. Practical experience has 

shown that it is necessary to evaluate many of these simplefacts exhaustively to keep FCX from "stalling". The EXHAUSTIVE declarations are made 

global over FCX by listing them in an include file named EXHAUSTV.SHR. 

F. FCX KNOWLEDGE BASES 

The structure of the FCX Flight Control Design Expert System is shown 

in the Fig. 1 diagram of the relationship of the 18 chained knowledge 

bases. Each knowledge base and its interaction with the other knowledge 

bases is discussed in turn in the following sections. Complete listings 

of the knowledge bases and related files are provided at the end of this 

Supplement. 

1. GENERATE 

The GENERATE knowledge base serves as the point of first contact with 

the user and acts as the' intermediary between the user and the other FCX 

experts. The FCX expert system is started by running the GENERATE knowledge base. One of the first activities performed automatically by 

GENERATE is to initialize certain simplefacts and attribute values as 

false using INIT statements. When a design session begins, GENERATE presents the user with the menu in Fig. 2 to identify, at the highest level, 

what he or she wishes to do. 

The first menu option allows the user to initiate specification of a 

new aircraft for which an FCS is to be designed. When this option is 

exercised, the AIRCRAFT expert is called to obtain all aircraft data independent of flight condition. 

The second option allows the user to specify a new flight condition 

for a previously specified aircraft. Selection of this option calls the 

FLTCOND expert for collection of all data dependent on flight condition 

such as trim values and stability derivatives. . 

When all aircraft and flight condition data has been obtained using 

the first two options, actual FCS design may be initiated by picking the 

third option to select a FCS architecture to be pursued. The ARCH expert 

TR-1228-1-11 10 
W 

2 

a 

W 

z 

W 

(3 

AIRCRAFT LT-J t 

IA I 

EAROOTIO 

11 SPECSET 

ASSESSOL SPECHKOL 

‘L7 PRSPCTUS 

DESIGN 

YAWDMPR ROLLDMPR 

r 

GAINSEL 

I 

ROOT ID 

Figure 1. Knowledge Base Structure in the 

FCX Flight Control Expert System 

TR-1228-1-11 11 
Specify a new aircraft for FCS design 

Specify a new flight condition for the 

current aircraft 

Select an FCS architecture for design 

Select a loop for design within the 

current architecture 

Store current design data on file 

Figure 2. FCX Main Menu 

will then be invoked to select the current architecture from the candidate 

architectures selected previously by the PRSPCTUS expert (discussed 

further below. 

An FCS feedback loop can be selected directly for design using the 

fifth option which invokes the DESIGN expert. This would ordinarily be 

done during iteration on a loop design. 

The last option allows the user to store all facts and data from the 

current design session on disk (the C drive, subdirectory FCSDAT) in the 

file LASTDSGN.CTX. 

The five options in the initial menu are implemented .in GENERATE as 

the five top level items in the goal outline structure. 

2. AIRCRAFT 

The AIRCRAFT expert handles definition of the aircraft for which the 

FCS is to be designed and functions primarily as a natural language interface at present. This includes collection of configuration parameters 

which are independent of flight condition such as geometry and mass properties. When this expert is invoked any previous aircraft data will be 

discarded, thus if the user desires to retain previous information it 

should be stored on file using the last option in GENERATE. AIRCRAFT 

first queries the user for a designation for the aircraft which is any 

name or one line phrase which the user specifies. AIRCRAFT next queries 

TR-1228-1-11 12 
for the classification (per MIL-F-8785) of the aircraft and the degrees of 

freedom for which control is to be exercised by the FCS. Presently expert 

assistance is available only for the lateral-directional DOF. When this 

preliminary data has been obtained, AIRCRAFT obtains the basic aircraft 

geometry and mass properties parameters by reading the aircraft basic data 

file (C:\FCSDAT\ACDATA.PRM). This ASCII file is written in the format 

required by the LEVEL5 READ function and contains the parameter listed in 

Fig. 3. 

This data is later used in the definition of the rigid body dynamics. 

The #*high frequency" dynamics of other components and structural dynamics 

are presently assumed independent of flight condition and are thus established under the aegis the AIRCRAFT expert. Further development of FCX 

would, at some point, account for the variation of the high frequency 

dynamics with flight condition (e.g., through the impact of surface hinge 

moment on actuator bandwidth available). At that time management of this 

activity would be given to the FLTCOND expert discussed next. 

Aircraft Kind 

Aircraft Class 

Planform Area 

Mean Aerodynamic Cord 

Wing Span 

Thrust Inclination 

Weight 

X Center of Gravity Mac 

X Center of Gravity 

Y Center of Gravity 

Z Center of Gravity 

X Moment of Inertia 

Y Moment of Inertia 

Z Moment of Inertia 

XY Product of Inertia 

XZ Product of Inertia 

YZ Product of Inertia 

(Text Phrase) 

(Roman Numeral) 

( ftA2) 

(ft) 

(ft) 

(deg) 

(Ibs) 

(%I 

(ft> 

(ft) 

(ft) 

(slug-ftA2) 

( slug-ftA2) 

(slug-ftA2) 

(slug-ftA2) 

(slug-ftA2) 

(slug-ftA2) 

Figure 3. Aircraft Basic Data File, 

"ACDATA . PRM" 

TR-1228-1-11 13 
At present the surface actuators, rudder and aileron (generic roll 

control), are modeled with first order lags specified by bandwidths 

obtained from the user. This data is transmitted to Program CC through 

the PROCALL interface which executes the "ACTUATOR" macro in Program CC. 

This macro generates the appropriate actuator transfer function models 

setting the inverse time constant to the user-specified bandwidth and 

stores them on file. 

The remaining high frequency dynamics in each surface channel are 

lumped as an effective time delay modeled with a second order Pade' 

approximation. The user is queried for the effective time delay in seconds for each channel. This number accounts for all components in the 

respective channel other than the actuator and rigid body dynamics, i.e. 

structural modes, bending and smoothing filters, digital computer cycle 

time, sensor lag, etc. This data is transmitted to Program CC through the 

PROCALL interface which executes the "TIMEDEL" macro in Program CC. This 

macro generates the appropriate second order Pade' transfer function 

models of the effective time delays and stores them on file. 

Once the basic flight-condition-independent aircraft data has been 

obtained, a flight condition must be established and AIRCRAFT calls up the 

FLTCOND expert for this activity. 

3. FLTCOND 

The FLTCOND expert establishes the flight condition parameters, such 

as speed, altitude and the trim values of all relevant state variables. 

It also obtains all other parameters needed to define the aircraft which 

are functions of flight condition, in particular the stability and control 

derivatives. FLTCOND is either invoked by the AIRCRAFT expert when a new 

aircraft is defined or it is called up by GENERATE when the user chooses 

the second, "Select a new flight condition . . .I1 option in GENERATE. In 

either event, FLTCOND first obtains the flight condition and trim state 

variables from the file "C:\FCSDAT\FLTCND.PRM". The parameters of this 

file are listed in Fig. 4. 

TR-1228-1-11 14 
t 

Flight Condition 

F1 ight Phase 

Flight Phase Category Literal 

Mach Number 

A1 t i tude 

True Airspeed 

Wing Span 

Trim Angle of Attack 

Trim Angle of Sideslip 

Trim Heading 

Trim Pitch Attitude 

Trim Bank Angle 

Trim Flight Path Angle 

Trim Roll Rate 

Trim Pitch Rate 

Trim Yaw Rate 

Trim Turn Rate 

Trim Normal Load Factor 

Trim Lateral Load Factor 

Trim Axial Load Factor 

(Text phrase) 

(Text phrase) 

(Mil-Spec code) 

Figure 4. Flight Condition and Trim File, 

"FLTCOND . PRM" 

FLTCOND displays the flight condition parameters on the screen and 

then proceeds to read the stability and control derivatives from the file 

C:\FCSDAT\DERIVS.PRM. This file contains both the stability axis and the 

body (fuselage reference line) derivatives as listed in Fig. 5. The 

stability axis derivatives are listed first followed by the corresponding 

body axis derivatives (denoted with a "b" suffix). 

When the above data has been obtained, FLTCOND proceeds to generate 

the "bare airframe'' dynamics which consists of the rigid body equations of 

motion alone. The bare airframe dynamics are generated first to simplify 

identification of the aircraft poles and zeros without the added complexity of the actuator and high frequency dynamics. This is done by first 

computing the elements in the bare airframe state space matrices as 

defined on Fig. 6. Presently the Fig. 6 model used in FCX is restricted 

to level flight (70 = 0). 

TR-1228-1-11 15 
YB 

qs' 

NB ' 

LP ' 

NP ' 

Lr ' 

Nr ' 

Y6a* 

L6a' 

N6a' 

Y6 r* 

L6r' 

N6r' 

YBb 

.LB'b 

NB'b 

Lp'b 

Np'b 

Lr'b 

Nr'b 

YCa*b 

L6a'b 

N6a'b 

YCr*b 

L6r'b 

N6r'b 

Figure 5. Stability and Control 

Derivatives File, DERIVS 

The bare airframe state matrices are then stored in the file 

$$BAREAC.SSM which is converted to a Program CC state space quadruple via 

the DATOCC interface. The PROCALL interface is then called to generate 

the bare airframe dynamics in the form of a transfer function matrix by 

exercising the $$BAREAC macro in Program CC. 

Once the bare aircraft dynamics have been generated, the corresponding literal approximate factors are generated by chaining to the LITFAC 

knowledge base which then chains to the BAROOTID expert to identify the 

bare airframe poles. When this is completed, control returns to FLTCOND. 

At this point definition of the aircraft and flight condition is complete, 

and the next step is definition of the specific requirements for the FCS 

design. This begins when FLTCOND calls the SPECSET expert. 

TR-1228-1-11 16 
x - ~+Bu 

[$IS] = 

- 

g COS e 

vT 

0 sin a -cos a 

0 

yv 0 0 

0 L; L' L' B P 

0 N; " " B P 

0 1 tan Bo 0 

1 0 0 0 

0 1 0 0 

0 0 1 0 

0 0 0 1 

0 cos a sin a 0 

0 -sin a cos a 0 

0 0 

0 0 - 

r 

Li 

Ni 

a 

Li 

Ni 

r r 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 

0 0 - 

Figure 6. Bare Airframe Model 

TR-1228-1-11 17 
4. LITFAC 

The LITFAC expert generates and evaluates the required literal 

approximate factors for poles and zeros of the bare airframe. The adjective "literal" is included in fact phrases such as "Literal roll spiral 4 

mode complexity IS real" to distinguish facts about literal approximate 

factors from corresponding facts about factors obtained by numerical factoring (in Program CC) . For numeric facts represented by symbols, a "$" 

is appended to denote a literal approximate factor. Thus "Wd$" denotes 

the literal approximate dutch roll undamped natural frequency which corresponds to the numerically factored value denoted by "Wd". 

LITFAC begins by evaluating the (absolute value of the) damping 

ratios of the roll-spiral and dutch roll modes using standard literal 

factors. These values are used by rules which determine the "complexity" 

(i.e., whether the roots are real or complex) of the two basic modes 

(roll-spiral and dutch roll). Additional rules then enumerate the real 

and/or complex poles based on mode complexity. The literal approximate 

pole parameters are then calculated (for the standard case -- real roll 

and spiral modes and complex duteh roll -- at present). 

When the literal factors are available, LITFAC immediately calls 

BAROOTID. 

5. BAROOTID 

The bare airframe poles are identified by the BAROOTID expert. This 

activity involves associating the bare airframe eigenvalues with the traditional physical mode names for aircraft lateral-directional dynamics-- 

i.e., dutch roll, spiral and roll subsidence. These physical associations 

are essential to the design process implemented in FCX. For instance 

application of the flying qualities specifications requires not only the 

numerical eigenvalues but a knowledge of which are the dutch roll poles as 

well. Computer programs for eigenvalue calculations have been in routine 

use in flight control system design for many years, however identification 

of the physical modes has always been the job of the human analyst. A 

distinguishing characteristic of FCX is that it "comprehends" the physical 

associations of the modes and can in fact assist the user in making them. 

TR-1228-1-11 ia 
At present the knowledge base for pole identification in BAROOTID is 

based on comparison of the literal (from LITFAC) and numerical (from Program CC) factors. Additional rules have been formulated for pole identification which would involve more active participation by the user and 

would provide more robust capability for unusual configurations (e.g., 

oblique wing aircraft) (Ref. 8). The interaction with Program CC to support these rules is more complex and thus they are not yet in BAROOTID. 

BAROOTID begins by accessing the numerical bare airframe pole parameters from Program CC. This is done by exercising the program TFCCLS 

which converts a Program CC file to a special format in the file GFCX 

(Fig. 7). The GFCX file contains the poles and zeros sorted in order of 

increasing frequency. Thus the NUMERIC fact "inverse time constant of 

real pole #2t' is associated with the real pole with the second lowest 

frequency. This would generally be expected to be the roll subsidence 

pole, but it might be a real dutch roll pole with, say, high AOA-induced 

loss of directional stability. The GFCX file also contains the number of 

real and complex poles and zeros. 

After the bare airframe pole parameters are identified, the number of 

real and complex poles are checked to verify that a physicaliy possible 

configuration exists. If so, a validity check is made on the literal 

approximate factors by comparing the number of literal real roots to the 

number of numerical real roots. If these are equal, the physical pole 

designation are assigned to the numerical pole closest to the corresponding literal pole. A final validity check of the literal factors is made 

by computing the separation between the literal and numerical parameters. 

A tolerance of about 20% is considered acceptable and if this is achieved 

control is returned to the FLTCOND expert system. 

6. SPECSET 

The SPECSET expert sets up the requirements and specifications for 

the given aircraft and flight condition. For those requirements derived 

from the military flying qualities specifications, the basic factors are 

the aircraft class and flight phase category. At present only a portion 

of the relevant requirements for Class IV (highly maneuverable) aircraft 

in Category CO (air-to-air combat) operation are included in FCX. 

TR-1228-1-11 19 
Number of numerical real zeros 

Number of numerical complex zero pairs 

Number of numerical real poles 

Number of numerical complex pole pairs 

Number of nonminimum phase numerical real zeros 

Number of nonminimum phase numerical complex zero pairs 

Number of unstable numerical real poles 

Number of unstable numerical complex pole pairs 

High frequency gain 

Inverse time constant of real zero j#1 

Inverse time constant of real zero #2 

Inverse time constant of. real zero #3 

Inverse time constant of real zero #4 

Inverse time constant of real zero #5 

Inverse time constant of real zero #6 

Damping ratio of complex zero pair #1 

Natural frequency of complex zero pair #1 

Damping ratio of complex zero pair #2 

natural frequency of complex zero pair #2 

Damping ratio of complex zero pair 93 

natural frequency of complex zero pair j/3 

Damping ratio of complex zero pair #4 

natural frequency of complex zero pair #4 

Damping ratio of complex zero pair #5 

natural frequency of complex zero pair #5 

Damping ratio of complex zero pair #6 

natural frequency of complex zero pair #6 

Inverse time constant of real pole 81 

Inverse time constant of real pole j,2 

Inverse time constant of real pole #3 

Inverse time constant of real pole #4 

Inverse time constant of real pole #5 

Inverse time constant of real pole 86 

Damping ratio of complex pole pair #1 

natural frequency of complex pole pair #1 

Damping ratio of complex pole pair #2 

natural frequency of complex pole pair {I2 

Damping ratio of complex pole pair #3 

natural frequency of complex pole pair j,3 

Damping ratio of complex pole pair #4 

natural frequency of complex pole pair #4 

Damping ratio of complex pole pair #5 

natural frequency of complex pole pair #5 

Damping ratio of complex pole pair #6 

natural frequency of complex pole pair #6 

Figure 7. Transfer Function File for Input to LEVELS, GFCX 

TR-1228-1-11 20 
The requirements are first set for each mode. When all modal 

requirements are set, the requirement set is considered complete (for the 

present capability of FCX) and the ASSESSOL expert is called to begin 

assessment of the unaugmented aircraft dynamics. 

sa I/Toa 

-e 

s + I/Taa . 

7. ASSESSOL 

-ras 1 s2-2/ras + 12/r: P 

- 

s'+~/T~s + 12/~,2 

The ASSESSOL expert performs various setup operations so that the 

bare airframe dynamics can be assessed. This assessment of the bare airframe dynamics provides the basis for the prospectus for control. The 

first job performed by ASSESSOL is formulation of the open loop aircraft 

model (Fig. 8) which consists of the bare airframe (rigid body) plus 

actuator plus effective time delay high frequency dynamics models previously created. The PROCALL interface is activated to run the OLAIRPLN 

macro in Program CC. This macro performs STATE command operations culminating in the transfer function matrix for the open loop aircraft. 

4 . Pb / 

rb 

Figure 8. Open Loop Aircraft 

Rudder Effective Delay Actuator 

I /Tar 

s + I/Tar 

-TyS 2 s2-2/rrs + IZ/S: 

*e - 

s2+2/rrs + IZ/T: 

)r 

TR-1228-1-11 

Bare 

Airframe , +k c 

- 

Ps 

rS r 

21 
When the poles and zeros have been identified, the requirements can 

be applied to assess the open loop dynamics. This is done by invoking the 

SPECHKOL expert which performs the detailed assessments. When SPECHKOL is 

finished, control is returned to ASSESSOL which calls the PRSPCTUS expert 

to define the prospectus for control based on the detailed open loop aircraft assessment. When PRSPCTUS is finished, control is again returned 

to ASSESSOL which immediately returns control to GENERATE. At that point 

the user is presented with the GENERATE main menu and would typically 

select the third option -- "Select an FCS architecture for design". 

8. SPECHKOL 

The SPECHKOL expert performs the actual numerical comparison of the 

bare airframe dynamics, as established in ASSESSOL, with the specialized 

requirements generated in SPECSET. The requirement comparisons are first 

made for each mode and then the overall assessment of the open loop dynamics is made based on the modal assessments. The rule for adequate open 

loop dynamics, at the present state of development of FCX, is that the 

dutch roll and roll subsidence modal dynamics are adequate. When this 

open loop assessment is completed, control is returned to ASSESSOL. 

9. PRSPCTUS 

The prospectus for control is established with the PRSPCTUS expert. 

PRSPCTUS first establishes the candidate feedback loops that might be 

useful in correcting the unaugmented aircraft deficiencies identified 

previously. Possibly useful loops are collected at this point without 

regard to redundancy of purpose. Next subsets of candidate loops are 

collected into candidate architectures. This eliminates some of the original redundancy by using rules that develop generally minimal loop structures that can be expected to provide an adequate basis for an FCS design. 

The candidate architectures represent the nuclei of complete FCS designs 

and provide the context for the detail design steps to follow. 

Next PRSPCTUS establishes a recommended order in which the candidate 

designs should be investigated to increase the chances that the most promising designs will be pursued first. 

TR-1228-1-11 22 
When the prospectus for control, in the form of candidate loops and 

ranked candidate architectures, is established, the control is transferred 

to the GENERATE expert. At this point the user would ordinarily exercise 

the third option in the GENERATE main menu, "Select an FCS architecture 

for design", to initiate FCS design. This option directly invokes the 

ARCH expert. 

10. ARCH 

The ARCH expert manages the actual selection of the "current architecture" -- the architecture for which a design is presently being pursued. This selection depends on which, if any, architectures have previously been pursued. Once the .current architecture has been selected, 

ARCH sets a recommended order in which the loops should be closed in the 

design sequence. When this has been done, ARCH calls the DESIGN expert to 

manage the actual design process for the current architecture. 

11. DESIGN 

Once the current architecture is defined, control passes to the 

DESIGN expert which manages the actual detail design process. 'The first 

activity is the selection of the "current loop" -- the loop, within the 

current architecture, which is presently being designed. This selection 

depends on which loops, if any, have previously been designed for the 

current architecture. Next, the current loop connections are defined; 

that is, each loop in the current architecture is identified as being open 

or closed. 

Once the current loop connections are defined DESIGN assigns the 

design of the current loop to a specialist. At present there are two 

specialists available: YAWDMPR which assists in the design of yaw damper 

loops and ROLLDMPR which assists in the design roll damper loops. Whenever one of the loop design experts completes a design iteration of the 

current loop, control is returned to DESIGN which determines whether a 

successful design has been found for the current architecture. When this 

occurs control is returned to GENERATE. 

TR-1228-1-11 23 
12. YAWDMPR 

The YAWDMPR expert assists in the design of yaw damper loops when 

requested by the DESIGN expert. The user is first presented with a 3 item 

menu : 

Perform complete yaw damper design 

Define yaw damper feedback equalization 

Define yaw damper gain 

If no previous design exists, the first option would be selected. 

YAWDMPR then begins by assisting the user in selection of the measurements 

to be used. A knowledgeable user can pick the desired measurements from a 

displayed list (with two entries -- roll rate and yaw rate). FCX monitors 

the selection and informs the user of an impractical selection (i.e. roll 

rate only). In this role YAWDMPR is assisting rather than consulting, 

however, the user can indicate that he doesn't know what measurements 

should be used. FCX will then attempt to use heuristics in the YAWDMPR 

knowledge base to recommend measurements. This may trigger additional 

queries to the user about the aircraft and its operation (i.e. whether or 

not it operates at high AOA). Basically YAWDMPR will attempt to determine if the angle of attack range is sufficiently restricted to allow the 

possibility of a single, properly tilted rate gyro or whether individual 

yaw and roll rate measurements are needed. 

When the necessary measurements have been defined, YAWDMPR will query 

the user for roll and yaw rate measurement blending coefficients (Fig. 9) 

for a two measurement design or for gyro tilt angle for a single sensor 

design. Again the knowledgeable user can directly specify his selection 

when queried or reply "unknown". In the later case, YAWDMPR will attempt 

to make recommendations based on knowledge in the rules. For a two measurement design, YAWDMPR will recommend a "stability axis" yaw damper and 

define the blending coefficients accordingly. This will require knowledge 

of the trim angle of attack which should have been obtained by the FLTCOND 

expert. If this is not available YAWDMPR will query the user for the 

value. 

TR-1228-1-11 24 
Roll 

rate Roll rate 

+ dr - blend coeff 

->(X)- > Aircraft pb 

Sensors blend coeff 

+I rb 

Effective yaw rate 

feedback signal 

rf 

Figure 9. Yaw Damper Diagram Showing Roll and 

Yaw Rate Blending Coefficients 

Once the blending coefficients or gyro tilt have been defined, an 

effective yaw rate signal (denoted rf) will have been defined and YAWDMPR 

invokes the SYSMOD, TFEXT and ROOTID experts to generate the effective 

open loop rf/6, transfer function (Fig. 10). YAWDMPR will then attempt to 

determine if the effective yaw rate is "suitable", i.e., whether or not 

the complex yaw rate zero is sufficiently well separated from the dutch 

roll pole to make a good yaw damper. If YAWDMPR has taken the lead in 

defining the measurements, the stability axis damper design will probably 

be adequate based on experience. YAWDMPR will query the user about the 

effective Wr/Wd dipole separation. 

When a suitable effective feedback signal is defined, YAWDMPR manages 

the definition of the feedback equalization. The form of the equalization 

-- a washout filter -- is part of the knowledge base. The user is queried 

for a value of the washout time constant, but if this is unknown by the 

user YAWDMPR will pick a value. Initially YAWDMPR will place the washout 

about an octave below the dutch roll. If this ultimately does not lead to 

a successful design, YAWDMPR contains additional rules for adjusting the 

washout which will come into play when the design is "cycled" for another 

iteration. 

TR-1228-1-11 25 
Once the washout time constant is set, YAWDMPR will again invoke 

SYSMOD, TFEXT and ROOTID to generate the open loop 6rf/Sr transfer function (Fig. 10). When this has been done, the last design step is selection of the gain. For a properly equalized open loop transfer function, 

this step is generic and YAWDMPR consults 'with GAINSEL to do the job. 

Once the loop gain is selected, the current yaw damper design is complete 

and must be assessed. In preparation for this, YAWDMPR again involves 

SYSMOD, TFEXT, and ROOTID to obtain the closed loop system dynamics. 

Next YAWDMPR invokes the ASSESS expert to assess the design against 

the appropriate requirements. If design assessment indicates that the 

relevant characteristic (i.e., dutch roll damping) is adequate, YAWDMPR 

pronounces the yaw damper design satisfactory and turns the job over to 

DESIGN. If the dutch roll damping is not satisfactory, YAWDMPR "cycles" 

to begin another iteration of the yaw damper design. In that case the 3 

option first level menu will appear so the user can change the washout, 

the gain, or start all over again. 

13. ROLLDMPR 

The ROLLDMPR expert assists in the design of roll dampers when 

requested by the DESIGN expert. ROLLDMPR uses a body axis roll rate 

measurement and assists the user in defining the feedback equalization and 

loop gain. When ROLLDMPR is invoked it first asks the user if he wishes 

to define the equalization or the loop gain. If no previous design is 

available, the equalization must be set first and SYSMOD, TFEXT and ROOTID 

are invoked to generate the open loop pb/6, transfer function. The 

equalization form is limited to a first order lead-lag filter which can 

take the form of a pure gain. The user can directly specify that the 

filter time constants and loop gain or request assistance from ROLLDMPR in 

making the selection. When the user is uncertain about equalization, 

ROLLDMPR interacts with Program CC to generate a pure gain root locus and 

will assist in examining the locus topology to determine the required 

equalization form. ROLLDMPR will ultimately set a lead time constant if 

required and select a lag that can be expected to be adequate. 

TR-1228-1-11 26 
I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

1 

I II 

I sa - 

O.L. 

Aircraft 

I 

I 

sr c 

* 

I I 

-7 I I PI 

r------- 1 

p220 I 

I p230 II 

Pt-l I 

1 I 

p210 I , 

I I 

I 

1 

I 

I 

I 

I 

i 

I 

I 

1 

1 

I 

I 

I 

I CONTROLLER I 

I p2 50 

Figure 10. Augmented Aircraft System Model 

TR-1228-1-11 27 
Once the equalization is set, ROLLDMPR will again call SYSMOD, TFEXT 

and ROOTID to generate the open loop 6,f/6, transfer function (Fig. 10). 

When this has been done, GAINSEL is invoked to set the loop gain. 

ROLLDMPR then invokes SYSMOD, TFEXT and ROOTID once more to generate the 

current closed loop dynamics which generally will also include the current 

yaw damper loop. When this is completed ROLLDMPR calls on ASSESS to 

assess the roll damper design. If design assessment indicates that the 

relevant characteristic (i.e., roll subsidence mode time constant) is 

adequate, ROLLDMPR pronounces the design satisfactory and turns the job 

over to DESIGN. Otherwise, ROLLDMPR "cycles" to iterate the roll damper 

des i gn . 

1 

14. GAINSEL 

The GAINSEL expert assists in the closure, i.e., the selection of the 

loop gain, for any loop once the nominal equalization has been established 

by one of the loop design specialists. The specialists (e.g., YAWDMPR) 

use heuristics to home in on likely equalization forms quickly, but gain 

selection for a properly equalized open loop transfer function is a more 

standardized operation. Thus this single expert handles closures of all 

loops. When GAINSEL is called, the user is presented with a four item 

menu. The first three options provide alternative procedures for setting 

the gain and the fourth terminates gain selection and returns to the loop 

design specialist which called GAINSEL. 

The first option allows the user to enter a gain value immediately. 

The second and third options assists the user in using conventional and 

Bode root locus techniques respectively to set the gain. In the second 

and third options GAINSEL manages the interaction with Program CC to generate the desired root locus on screen. 

15. SYSMOD 

' 

The SYSMOD expert handles the generation of the closed loop model for 

the aircraft plus flight control system. For each architecture (presently 

only one -- yaw damper plus roll damper) a generic structure for the 

closed loop system is captured through LEVEL5 rules and Program CC macros 

TR-1228-1-11 28 
. 

and data structures. Figure 10 shows the generic structure for the yaw 

damper plus roll damper architecture. The symbols consisting of a "P" 

with a numeric subscript are the Program CC identifiers for specific state 

space quadruples. Corresponding transfer function matrices and transfer 

functions are denoted by replacing the P's with "H" or "G" respectively. 

When SYSMOD is called it generates the numerical values of the basic 

state quadruples in Figure 10 (using the current values of gains and time 

constants) and stores them on file in LEVEL5 format. The DATOCC program 

is then activated to convert these to state quadruple files in Program CC 

format ("$$P" files). The "FCSMODEL" Program CC macro is then initiated 

to generate the "closed loop" system transfer function matrix, P260 

(whether the loops are really closed or not depends on the values of the 

loop gains.) Specific transfer functions needed in the analysis are also 

extracted from the system transfer function matrix and stored on file (as 

Program CC "$$G" files.) When the closed loop system dynamics have been 

defined, control is returned to the calling expert. 

16. TFEXT 

The TFEXT expert performs the transfer of specified transfer functions, stored on disk as Program CC "$$G" files to LEVEL5 knowledge bases. 

The TTCCL5 program is activated to convert a file to LEVEL5 format stored 

in file TFTRANS.PRM. The file format is defined in Fig. 7. The TFTRANS 

file is then read into the TFEXT knowledge base and control is returned to 

the knowledge base which called TFEXT. 

17. ROOTID 

The ROOTID expert identifies poles and zeros of the systems consisting of the aircraft plus partial or complete augmentation. This activity 

is analogous to that performed by BAROOTID and involves associating aircraft eigenvalues with the physical modes, However, ROOTID deals with 

more general augmented aircraft configurations and, in general, this is a 

much more complex problem. Rules based on the bare airframe literal 

approximate factors are not generally useful for this application, and 

closed loop approximate factors are not generally available (for an 

TR-1228-1-11 29 
example of approximate factors for "superaugmented" aircraft, see Ref. 

9). This complication arises often in flight control analysis (e.g., it 

is central to problems in application of flying qualities specifications 

to lower order equivalent systems representing highly augmented aircraft, 

Ref. 10). Thus much more work is required to handle the general root identification process for FCX. The present development of ROOTID is quite 

elementary and restricted to the one architecture accommodated by FCX. 

The identification is performed by reference to several rules about the 

standard characteristics of the poles for the basic loop structures. 

18. ASSESS 

The ASSESS expert performs essentially the same assessment function 

as the SPECHKOL expert, but for the system with one or more FCS loops 

included instead of the open loop aircraft. The primary reason for having 

distinct SPECHKOL and ASSESS knowledge bases is limitations in the grammatical constructions of fact phrases in LEVEL5. These two modules could 

and probably should be combined in future developments. ASSESS compares 

the dynamics of the current assessment model to the specialized requirements set in SPECSET. When the requirement comparisons are completed, 

control is returned to the loop design expert which requested the assessment. The loop design expert then decides if the loop design is adequate 

based on the assessment of the relevant dynamic characteristics. 

G. UTILITY PROGRAMS 

A number of utility programs written in compiled BASIC are used to 

interface LEVEL5 and Program CC. 

1. DATOCC.EXE 

File Type : Compiled BASIC program 

Purpose : Converts files that are output by LEVEL5 into a form that 

Program CC can read. 

Inputs : 1. Directory where the LEVEL5 data file will be stored 

2. Name of the file LEVEL5 will create 

3. Directory where the Program CC file will be stored 

4. Name of the Program CC file that will be created 

TR-1228-1-11 30 
Description: Program CC uses a specific file format to save and recall 

the systems it needs. LEVEL5 also uses a specific file 

format to save and recall its data. These 2 file formats 

are not compatible, therefore a bridge program was written 

to convert LEVEL5 data files into a form that Program CC 

can use. DATOCC.EXE performs this conversion. 

The program will look for the LEVEL5 data file in the given 

directory and then convert the contents of this file into 

Program CC form and save it in the subdirectory given, 

using the specified Program CC file name. 

2. PROCALL.= 

File Type : 

Purpose 

Inputs 

Description : 

Compiled BASIC program 

Allows external programs to be executed from within 

LEVEL5. 

1. 

2. Name of the external program to be executed 

3. Instructions to be passed to the external program 

Directory where the program to be executed is stored 

(macros, etc.) 

This module is used to call external programs from within 

LEVELS. The advantage of this program over the LEVEL5 

ACTIVATE command is that with this program you maypass 

parameters to the program you are calling, without having 

to modify the called program. 

The program looks for the specified program in the specified directory and executes it. The user may pass parameters to the program if it is necessary. 

3. TFCCL5.W 

File Type : Compiled BASIC program 

Purpose : Converts a Program CC transfer function file 

into a form that LEVEL5 may use. 

Inputs : 1. Directory where the Program CC transfer 

function file is located 

2. Program CC transfer function file name 

3, File name and directory where the LEVEL5 

compatible file will be stored 

Description: This purpose takes a Program CC transfer function file and 

converts it into a form that LEVEL5 can use. It only works 

with Program CC transfer function files (i.e., $$Gi files). 

The LEVEL5 file can contain a maximum of 6 first order 

zeros, 6 second order zeros, 6 first order poles, and 6 

second order poles. 

TR-1228-1-11 31 
TR-1228-1-11 

The program searches the specified directory for the specified $$Gi file name and then creates the LEVEL5 compatible 

file and stores it using the specified name and subdirectory. 

The LEVEL5 file has the following format: 

Number of numerical real zeros 

Number of numerical complex zero pairs 

Number of numerical real poles 

Number of numerical complex pole pairs 

Number of nonminimum phase numerical real zeros 

Number of nonminimum phase numerical complex zero pairs 

Number of unstable numerical real poles 

Number of unstable numerical complex pole pairs 

High frequency gain 

Inverse time constant of real zero #l 

Inverse time constant of real zero #2 

Inverse time constant of real zero #3 

Inverse time constant of real zero #4 

Inverse time constant of real zero 115 

Inverse time constant of real zero #6 

Damping ratio of complex zero pair 111 

Natural frequency of complex zero pair #1 

Damping ratio of complex zero pair #2 

Natural frequency of complex. zero pair #2 

Damping ratio of complex zero pair #3 

Natural freqiiency of complex zero pair #3 

Damping ratio of complex zero pair #I4 

Natural frequency of complex zero pair #4 

Damping ratio of complex zero pair 115 

Natural frequency of complex zero pair #5 

Damping ratio of complex zero pair #6 

Natural frequency of complex zero pair #6 

Inverse time constant of real pole #l. 

Inverse time constant of real pole 112 

Inverse time constant of real pole 113 

Inverse time constant of real pole #4 

Inverse time constant of real pole #5 

Inverse time constant of real pole #6 

Damping ratio of complex pole pair {I1 

Natural frequency of complex pole pair #1 

Damping ratio of complex pole pair #2 

Natural frequency of complex pole pair 112 

Damping ratio of complex pole pair #3 

Natural frequency of complex pole pair #3 

Damping ratio of complex pole pair #4 

Natural frequency of complex pole pair #4 

Damping ratio of complex pole pair #5 

Natural frequency of complex pole pair #5 

Damping ratio of complex pole pair #6 

Natural frequency of complex pole pair #6 

32 
H. PROGRAM CC MACROS 

Program CC macros are ASCII text files containing sequences of 

Program CC commands to perform special operations initiated by the FCX 

knowledge bases. 

1. BAREAC.MAC 

File Type : Program CC macro file 

Purpose : Creates a transfer function matrix from a state space 

quadruple 

Inputs : 1. Program CC state space quadruple file name ($$Pi) 

2. Program CC transfer function matrix file name ($$Hi) 

Description: This Program CC macro takes the specified state space 

quadruple and converts it to a transfer function matrix. 

The macro then displays the matrix, and returns to be the 

LEVEL5 knowledge base. 

2. 0LAIRPLN.MAC 

File Type : Program CC macro file 

Purpose : Creates the open loop aircraft lateral dynamics 

state space quadruple. 

Inputs : None 

Description: This Program CC macro creates the open loop airplane dynamics state space quadruple. Given the forward path (aileron 

actuator, $$G50; aileron delay, $$G60; rudder actuator 

$$G51; and rudder delay, $$G61) and the bare airframe 

dynamics ($$PlOO) the open loop airplane dynamics quadruple 

($$P110) will be created. The macro first creates a feed 

forward block ($$P70) that contains the aileron and rudder 

dynamics, then it computes the state space quadruple, and 

finally it computes and displays the open loop transfer 

function matrix. 

3. FORWARD.MAC 

File Type : Program CC macro file 

Purpose : Creates the open loop forward path for the 

lateral dynamics system. 

TR-1228-1-11 33 
Inputs 

Description : 

1. Aileron actuator time constant 

2. Rudder actuator time constant 

3. Aileron effective time delay 

4. Rudder effective time delay 

This macro creates the forward loop paths for the lateral 

dynamics system. Given the aileron and rudder time constants and effective time delays, it creates the forward 

loop transfer functions. The aileron actuator is stored in 

$$G50, the rudder actuator is stored in $$G51, the aileron 

time delay is stored in $$G60, and the rudder time delay is 

stored in $$G61. The time delays are computed as second 

order Pade approximations. 

4. FCSMODEL . MAC 

File Type : Program CC macro file 

Purpose : Generates the closed loop lateral dynamics 

transfer function matrix. 

Inputs : None 

Description: This Program CC macro creates the complete closed loop 

lateral dynamics transfer function matrix. In order for 

this macro to work correctly the user must first have 

created the open loop aircraft state space quadruple 

($$P110, this includes the bare airframe quadruple and the 

forward path 0LAIRPLN.MAC). This macro displays the yaw 

rate and roll rate feedback transfer functions, creates the 

feedback steady state quadruple, and finally creates and 

displays the closed loop transfer function matrix 

($$H260)4. 

5. 0LTF.MAC 

File Name : Program CC macro file 

Purpose : Compute various open loop transfer functions for the 

lateral dynamics system. 

Inputs : None . Description: This Program CC macro computes open loop transfer functions 

at various points in the lateral dynamics system. This 

allows the user to evaluate the system both open and closed 

loop. The open loop transfer functions that are calculated 

are : 

TR-1228-1-11 34 
pb/6a ($$G26012) 

rb/6r ($$G26021) 

rf/6r ($$G26031) 

Crf/Sr ($$G26041) 

Gaf/Sa ($$G26052) 

To evaluate the system open loop, you must set the feedback .- 

gains to zero. This means that Kr (yaw rate feedback gain) 

should be set to zero if you want to open the yaw rate 

feedback, and Kp (roll rate feedback gain) should be set to 

zero if you want to open the roll rate feedback. When 

looking at the open loop transfer functions for Srf/6r and 

6af/6a the gains (Kr and Kp) are equal to 1 so that a suitable closed loop gain may be obtained. 

I. INSTALLATION OF THE FCX SOFTWARE 

The FCX software is set up to be run from a hard disk (the C: drive) 

on an IBM PC-compatible computer under the DOS operating system. Four 

subdirectories are used: C:\FCSXPRT, C:\FCSDAT, C:\STI and C:\L5. The 

FCSXPRT subdirectory contains the FCX "include" files and knowledge bases 

both as .PRL files and as compiled .KNB files (Table 1). The FCSDAT subdirectory holds various data files created by FCX. Subdirectory C:\STI 

contains. the utility programs and Program CC macros listed in Table 2 as 

well as the actual Program CC files. The LEVEL5 program is installed in 

subdirectory C:\L5. 

J. INITIATING A FCX SESSION 

An FCX session is initiated by bringing up the LEVEL5 environment as 

explained in Ref. 1. When the first ("What would you like to do ?'I) menu 

appears, select the first option -- "Run a knowledge base". When the "Run 

which knowledge base ?I' menu appears, press the F3 function key to change 

the default directory name. Enter "C:\FCSXPRT" when prompted for the 

directory name to change to. When the "Run which knowledge base ?" menu 

reappears with the names of the 18 FCX knowledge bases, select "GENERATE". 

When the GENERATE banner appears, press the F3 function key to continue and you will be asked whether the previous data should be restored. 

Ordinarily when starting a new design this will be false. After this 

decision the FCX main menu will appear. If a new aircraft is to be specified, the first option should be selected. Aircraft, flight condition and 

TR-1228-1-11 35 
TABLE 1. INCLUDE FILES AND KNOWLEDGE BASES IN C:\FCSXPRT 

NAME EXT. 

Include Files 

SHAREFCT SHR 

INITATT 

MULTI SHR 

EXHAUSTV SHR 

Knowledge Bases 

AIRCRAFT PRL 

TFEXT PRL 

FLTCOND PRL 

ASSESSOL PRL 

SPECSET PRL 

PRSPCTUS PRL 

ROLLDMPR PRL 

ASSESS PRL 

YAWDMPR PRL 

GAINSEL PRL 

DESIGN PRL 

BAROOTID PRL 

ARCH PRL 

SYSMOD PRL 

GENERATE PRL 

SPECHKOL PRL 

LITFAC PRL 

ROOTID PRL 

SIZE (kb) 

30056 

1074 

203 

8895 

8952 

10181 

10384 

5598 

3329 

5723 

15664 

6551 

33569 

3699 

10070 

14872 

4134 

7056, 

7840 

5203 

4802 

5127 

TABLE 2. UTILITIES AND MACROS IN C:\STI 

NAME EXT . 

Utility programs 

DATOCC EXE 

PROCALL EXE 

TFCCL5 EXE 

BASRUN EXE 

BRUN4O EXE 

Program CC macros 

FORWARD MAC 

BAREAC MAC 

FCSMODEL MAC 

OLAIRPLN MAC 

TIMEDEL MAC 

ACTUATOR MAC 

OLTF MAC 

BAPDA MAC 

BODESIG MAC 

ROOTLOC MAC 

SIZE(Kb) 

14814 

12348 

18364 

31744 } Basic Libraries 76816 

136 

42 

747 

457 

45 

47 

760 

248 

55 

31 

TR-133A-1 -TT 
L 

stability derivative data files -- ASCII files ACDATA.PRM (Fig. 3), 

FLTCOND.PRM (Fig. 4) and DERIVS.PRM (Fig. 5) respectively -- must be 

available on subdirectory C:\FCSDAT. After the aircraft is defined, FCX 

will proceed to definition of the candidate architectures. When this has 

been done the main menu in GENERATE will appear. Ordinarily at this point 

the third option "Select an architecture for design" would be chosen to 

proceed with flight control design. 

TR-1228-1-11 37 
REFERENCES 

1. 

2. 

3. 

4. 

5 ._ 

6. 

7. 

8. 

9. 

10. 

LEVEL5 User's Manual (PC Version), Expert System Software Information Builders, Inc., New York, NY, 1987. 

Thompson, Peter M., Program CC Version 3 User's Guide, Systems Technology, Inc., Hawthorne, CA, May 1985. 

Thompson, Peter M., Proeram CC Version 4 Tutorial and User's Guide, 

Systems Technology, Inc., Hawthorne, CA, May 1988. 

Thompson, Peter M., Program CC Version 4 Reference Manual. Vols. I 

and 11, Systems Technology, Inc., May 1988. 

Winston, Patrick Henry, Artificial Intelligence, Addison-Wesley Publishing Company, Inc., USA and Canada, 1984. 

Pang, G.K.H., J-M. Boyle, and A.G.J. MacFarlane, "An Expert System 

for Computer-Aided Linear Multivariable Control System Design," 

Proceedings of the IEEE Control Systems Society Third SvmDosium 

on Computer-Aided Control System Design (CACSDI, Arlington, VA, 

Sept. 1986. 

Munro, N., D.K. Frederick, and 2. Palaskas, "An Adaptive CACSD Dialogue Facility, I' Proceedings - of the IEEE Control Systems Society 

Third Symposium on Computer-Aided Control System Design (CACSD)., 

Arlington, VA, Sept. 1986. 

Myers, Thomas T., Progress ReDort 1/13. Contract No. NAS1-17987. for 

the Deriod 15 January throuvh - 1 June 1987, Systems Technology, 

Inc., June 1987. 

Myers, T.T., D.T. McRuer, D.E. Johnston, Flying Qualities and Control 

System Characteristics for SuDeraugmented Aircraft, NASA 

CR-170419, Sept. 1984. 

Hoh, Roger H., David G. Mitchell, Irving L. Ashkenas, et al., Proposed Mil Standard and Handbook -- Flying Oualities of Air 

Vehicles. Vol. I: Proposed MIL Standard, AFWAL-TR-82-3081(1), 

Nov. 1982. 

Hoh, Roger H., David G. Mitchell, Irving L. Ashkenas, et al., Proposed Mil Standard and Handbook -- Flying Qualities of Air 

Vehicles. Vol. 11: Proposed MIL Handbook, AFWAL-TR-82-3081(11), 

Nov. 1982. 

TR-1228-1-11 38 
APPENDIX A 

FCX FLIGHT CONTROL DESIGN EXPERT SYSTEM 

KNOWLEDGE BASE LISTINGS 

TR-1228-141 39 
TR-1228-1-11 

SHAREFCT.SHR 

40 
! "SHAREFCT. SHR" 

! 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT. SHR" 

! 

................................................................... 

! 

! 

! Facts defined in GENERATE 

I ! Shared Facts Declarations 

SHARED NUMERIC g 

................................................................... 

! "AIRCRAFT. FCT" 

! 

! AIRCRAFT DEFINITION (AIRCRAFT) 

! Externally defined facts used in AIRCRAFT 

! Flight and trim conditions have been obtained 

! Stability and control derivatives have been obtained 

! Open loop aircraft dynamics have been obtained 

! Literal approximate factors have been obtained 

! Requirements must be set for the current case 

! Complete aircraft data has been obtained 

! Facts defined in AIRCRAFT 

SHARED SIMPLEFACT Aircraft has been designated 

AND SIMPLEFACT Aircraft has been classified 

AND SIMPLEFACT Degrees of freedom for control have been defined 

AND SIMPLEFACT aircraft basic data file has been read 

AND SIMPLEFACT aileron actuator bandwidth has been specified 

AND SIMPLEFACT rudder actuator bandwidth has been specified 

AND SIMPLEFACT aileron channel effective time delay has been specified 

AND SIMPLEFACT rudder channel effective time delay has been specified 

AND SIMPLEFACT aileron actuator transfer function has been generated 

AND SIMPLEFACT rudder actuator transfer function has been generated 

AND SIMPLEFACT aileron time delay transfer function has been generated 

AND SIMPLEFACT rudder time delay transfer function has been generated 

AND SIMPLEFACT Actuator dynamics have been defined 

AND SIMPLEFACT High frequency dynamics have been defined 

AND SIMPLEFACT Aircraft basic data has been obtained 

AND SIMPLEFACT Aircraft basic data must be obtained 

4 SHARED ATTRIBUTE Aircraft classification IS Class I 

AND ATTRIBUTE Aircraft classification IS Class I1 

AND ATTRIBUTE Aircraft classification IS Class I11 

AND ATTRIBUTE Aircraft classification IS Class IV 

AND ATTRIBUTE aircraft type IS Fighter 

TR-1228-1-11 41 
I 

I 

AND ATTRIBUTE aircraft type IS Interceptor 

AND ATTRIBUTE aircraft type IS Attack 

AND ATTRIBUTE aircraft type IS Tactical reconnaissance 

AND ATTRIBUTE aircraft type IS Observation 

AND ATTRIBUTE aircraft type IS Trainer for Class IV aircraft 

AND ATTRIBUTE aircraft type IS generic high maneuverability aircraft 

AND ATTRIBUTE Degrees of freedom for control ARE lateral directional axes 

AND ATTRIBUTE Degrees of freedom for control ARE longitudinal axes 

SHARED NUMERIC Planform Area 

AND NUMERIC Mean Aerodynamic Cord 

AND NUMERIC Wing Span 

AND NUMERIC Thrust Inclination 

AND NUMERIC Weight 

AND NUMERIC X Center of Gravity Mac 

AND NUMERIC X Center of Gravity 

AND NUMERIC Y Center of Gravity 

AND NUMERIC Z Center of Gravity 

AND NUMERIC X Moment of Inertia 

AND NUMERIC Y Moment of Inertia 

AND NUMERIC Z Moment of Inertia 

AND NUMERIC XY Product of Inertia 

AND NUMERIC XZ Product of Inertia 

AND NUMERIC YZ Product of Inertia 

AND NUMERIC roll control actuator bandwidth 

AND NUMERIC rudder actuator bandwidth 

AND NUMERIC roll control channel effective time delay 

AND NUMERIC rudder channel effective time delay 

SHARED STRING Aircraft Kind 

AND STRING Aircraft Class 

AND STRING Aircraft designation 

................................................................. 

! "FLTCOND . PRL" 

! 

! FLIGHT CONDITION DEFINITION (FLTCOND) 

! Externally defined facts used in FLTCOND 

! Aircraft basic data has been obtained 

! dutch roll damping ratio spec is set 

! 

! dutch roll damping ratio spec 

! Facts defined in FLTCOND 

SHARED SIMPLEFACT Flight and trim conditions have been obtained 

AND SIMPLEFACT Stability and control derivatives have been obtained 

AND SIMPLEFACT State matrix calculations have been obtained 

AND SIMPLEFACT Bare airframe dynamics have been obtained 

Requirements are set for the current case 

I 

I TR-1228-1-11 42 
AND SIMPLEFACT Literal approximate factors have been obtained 

AND SIMPLEFACT Complete aircraft data has been obtained 

AND SIMPLEFACT Requirements must be set for the current case 

SHARED ATTRIBUTE Flight phase category IS Category CO 

SHARED NUMERIC Mach Number 

AND NUMERIC Altitude 

AND NUMERIC True Airspeed 

AND NUMERIC Wing Span 

AND NUMERIC Trim Angle of Attack 

AND NUMERIC Trim Angle of Sideslip 

AND NUMERIC Trim Heading 

AND NUMERIC Trim Pitch Attitude 

AND NUMERIC Trim Bank Angle 

AND NUMERIC Trim Flight Path Angle 

AND NUMERIC Trim Roll Rate 

AND NUMERIC Trim Pitch Rate 

AND NUMERIC Trim Yaw Rate 

AND NUMERIC Trim Turn Rate 

AND NUMERIC Trim Normal Load Factor 

AND NUMERIC Trim Lateral Load Factor 

AND NUMERIC Trim Axial Load Factor 

AND NUMERIC YB 

AND NUMERIC L/?' 

AND NUMERIC NB' 

AND NUMERIC Lp' 

AND NUMERIC Np' 

AND NUMERIC Lr' 

AND NUMERIC Nr' 

AND NUMERIC Y6a# 

AND NUMERIC L6a' 

AND NUMERIC N6a' 

AND NUMERIC Y6r# 

AND NUMERIC L6r' 

AND NUMERIC N6r' 

AND NUMERIC YBb 

AND NUMERIC v'b 

AND NUMERIC NB'b 

AND NUMERIC Lp'b 

AND NUMERIC Np'b 

AND NUMERIC Lr'b 

AND NUMERIC Nr'b 

AND NUMERIC Y6a#b 

AND NUMERIC LCa'b 

AND NUMERIC N6a'b 

AND NUMERIC Y6r#b 

AND NUMERIC L6r'b 

AND NUMERIC N6r'b 

AND NUMERIC SINao 

AND NUMERIC NSINao 

AND NUMERIC COSao 

TR-1228-1-11 43 
AND NUMERIC NCOSQO 

AND NUMERIC GCOSBo 

AND NUMERIC TANBo 

AND NUMERIC ZERO 

AND NUMERIC ONE 

AND NUMERIC TWO 

AND NUMERIC FOUR 

AND NUMERIC SIX 

AND NUMERIC Yv 

AND NUMERIC aorad 

AND NUMERIC Borad 

AND NUMERIC SINao 

AND NUMERIC NSINao 

AND NUMERIC COSao 

AND NUMERIC NCOSao 

AND NUMERIC GCOSBo 

AND NUMERIC TANBo 

AND NUMERIC Uo 

SHARED STRING Flight Condition 

AND STRING Flight Phase 

AND STRING Stl 

AND STRING St2 

AND STRING St7 

AND STRING St8 

AND STRING St9 

................................................................. 

! Bare Airframe Literal Approximate Factors (LITFAC) 

I 

SHARED SIMPLEFACT Bare airframe dynamics have been defined 

AND SIMPLEFACT Initial literal parameters have been calculated 

AND SIMPLEFACT Literal poles have been enumerated 

AND SIMPLEFACT Literal roll spiral coupling exists 

AND SIMPLEFACT Literal factors are defined for bare airframe poles 

AND SIMPLEFACT Literal factors are defined 

SHARED ATTRIBUTE Literal roll spiral mode complexity IS complex 

AND ATTRIBUTE Literal roll spiral mode complexity IS real 

AND ATTRIBUTE Literal dutch roll mode complexity IS complex 

AND ATTRIBUTE Literal dutch roll mode complexity IS real 

SHARED NUMERIC Wrs$abs 

AND NUMERIC Wd$abs 

AND NUMERIC ZWrs$abs 

AND NUMERIC ZWd$abs 

AND NUMERIC Zrs$abs 

AND NUMERIC Zd$abs 

AND NUMERIC Number of literal real poles 

AND NUMERIC Number of literal complex pole pairs 

AND NUMERIC ITr$ 

TR-1228-1-11 44 
AND NUMERIC ITS$ 

AND NUMERIC Wd$ 

AND NUMERIC ZWd$ 

AND NUMERIC Zd$ 

................................................................. 

! 

I Bare Airframe Pole and Zero Identification (BAROOTID) 

! 

! Externally defined facts used in BAROOTID 

! Number of literal real poles 

! Facts defined in BAROOTID 

SHARED SIMPLEFACT Generic bare airframe poles are defined 

AND SIMPLEFACT Bare airframe poles are identified 

AND SIMPLEFACT Literal factors are defined 

AND SIMPLEFACT Bare airframe identification transfer function has been read 

AND SIMPLEFACT Bare airframe real poles are feasible 

AND SIMPLEFACT Bare airframe complex poles are feasible 

AND SIMPLEFACT Bare airframe poles are feasible 

AND SIMPLEFACT Literal poles are valid at check #2 

AND SIMPLEFACT Bare airframe poles are tentatively identified 

AND SIMPLEFACT Literal poles are valid at check #3 

AND SIMPLEFACT Bare airframe poles are identified 

SHARED ATTRIBUTE Literal roll spiral mode complexity IS real 

AND ATTRIBUTE Literal roll spiral mode complexity IS complex 

AND ATTRIBUTE Literal dutch roll mode complexity IS real 

AND ATTRIBUTE Literal dutch roll mode complexity IS complex 

SHARED NUMERIC Number of numerical real zeros 

AND NUMERIC Number of numerical complex zero pairs 

AND NUMERIC Number of numerical real poles 

AND NUMERIC Number of numerical complex pole pairs 

AND NUMERIC Number of nonminimum phase numerical real zeros 

AND NUMERIC Number of nonminimum phase numerical complex zero pairs 

AND NUMERIC Number of unstable numerical real poles 

AND NUMERIC Number of unstable numerical complex pole pairs 

AND NUMERIC High frequency gain 

AND NUMERIC Inverse time constant of real zero #1 

AND NUMERIC Inverse time constant of real zero #2 

AND NUMERIC Inverse time constant of real zero #3 

AND NUMERIC Inverse time constant of real zero #4 

AND NUMERIC Inverse time constant of real zero #5 

AND NUMERIC Inverse time constant of real zero #6 

AND NUMERIC Damping ratio of complex zero pair #1 

AND NUMERIC natural frequency of complex zero pair #1 

AND NUMERIC Damping ratio of complex zero pair #2 

AND NUMERIC natural frequency of complex zero pair #2 

AND NUMERIC Damping ratio of complex zero pair #3 

TR-1228-1-11 45 
AND NUMERIC natural frequency of complex zero pair #3 

AND NUMERIC Damping ratio of complex zero pair #4 

AND NUMERIC natural frequency of complex zero pair #4 

AND NUMERIC Damping ratio of complex zero pair #5 

AND NUMERIC natural frequency of complex zero pair #5 

AND NUMERIC Damping ratio of complex zero pair #6 

AND NUMERIC natural frequency of complex zero pair #6 

AND NUMERIC Inverse time constant of real pole #1 

AND NUMERIC Inverse time constant of real pole #2 

AND NUMERIC Inverse time constant of real pole #3 

AND NUMERIC Inverse time constant of real pole #4 

AND NUMERIC Inverse time constant of real pole #5 

AND NUMERIC Inverse time constant of real pole #6 

AND NUMERIC Damping ratio of complex pole pair #1 

AND NUMERIC natural frequency of complex pole pair #1 

AND NUMERIC Damping ratio of complex pole pair #2 

AND NUMERIC natural frequency of complex pole pair #2 

AND NUMERIC Damping ratio of complex pole pair #3 

AND NUMERIC natural frequency of complex pole pair #3 

AND NUMERIC Damping ratio of complex pole pair #4 

AND NUMERIC natural frequency of complex pole pair #4 

AND NUMERIC Damping ratio of complex pole pair #5 

AND NUMERIC natural frequency of complex pole pair #5 

AND NUMERIC Damping ratio of complex pole pair #6 

AND NUMERIC natural frequency of complex pole pair #6 

AND NUMERIC Number of bare airframe numerical real poles 

AND NUMERIC Number of bare airframe numerical complex pole pairs 

AND NUMERIC Inverse time constant of bare airframe real pole #1 

AND NUMERIC Inverse time constant of bare airframe real- pole #2 

AND NUMERIC Damping ratio of bare airframe complex pole pair #1 

AND NUMERIC natural frequency of bare airframe complex pole pair #1 

AND NUMERIC ITS 

AND NUMERIC ITr 

AND NUMERIC Zd 

AND NUMERIC Wd 

................................................................. 

! "SPECSET. FCT" 

! 

! AIRCRAFT DYNAMICS REQUIREMENTS SETUP (SPECSET) 

! Externally defined facts used in SPECSET 

! open loop aircraft model is setup 

! 

! open loop aircraft poles and zeros have been identified 

! 

! open loop aircraft dynamics are adequate 

! open loop aircraft assessment is complete 

open loop aircraft dynamics have been obtained 

open loop aircraft spec comparison is complete 

TR-1228-1-11 46 
! Aircraft classification IS Class IV 

! Flight phase category IS Category CO 

! Facts defined in SPECSET 

SHARED SIMPLEFACT Dutch roll damping ratio spec is set 

AND SIMPLEFACT Dutch roll natural frequency spec is set 

AND SIMPLEFACT Dutch roll mode specs are set 

AND SIMPLEFACT Roll subsidence mode time constant spec is set 

AND SIMPLEFACT Roll subsidence mode specs are set 

AND SIMPLEFACT Dutch roll mode specs are set 

AND SIMPLEFACT Lateral directional specs are set 

AND SIMPLEFACT Requirements are set for the current case 

SHARED NUMERIC Dutch roll damping ratio spec 

AND NUMERIC Roll subsidence mode time constant spec 

................................................................. 

! "ASSESSOL. FCT" 

! FACTS for OPEN LOOP AIRCRAFT ASSESSEMENT (ASSESSOL) 

SHARED SIMPLEFACT Complete aircraft data has been obtained 

AND SIMPLEFACT open loop aircraft model is setup 

AND SIMPLEFACT open loop aircraft dynamics have been obtained 

AND SIMPLEFACT open loop aircraft poles and zeros have been identified 

AND SIMPLEFACT open loop aircraft spec comparison is complete 

AND SIMPLEFACT open loop aircraft dynamics are adequate 

AND SIMPLEFACT open loop aircraft assessment is complete 

.................................................................. 

! 'I SPECHKOL . FCT" 

! 

! BARE AIRCRAFT DYNAMICS SPECIFICATION CHECKER (SPECHKOL) 

! Externally defined facts used in SPECKOL 

! 

! 

! bare airframe roll subsidence mode inverse time constant 

! Roll subsidence mode time constant spec 

bare airframe dutch roll damping ratio 

dutch roll damping ratio spec 

! Facts defined in SPECKOL 

SHARED SIMPLEFACT bare airframe dutch roll damping ratio has been assessed 

AND SIMPLEFACT bare airframe dutch roll mode dynamics are adequate 

AND SIMPLEFACT bare airframe dutch roll mode has been assessed 

AND SIMPLEFACT bare airframe roll mode time constant has been assessed 

AND SIMPLEFACT bare airframe roll subsidence mode dynamics are adequate 

AND SIMPLEFACT bare airframe roll subsidence mode has been assessed 

TR-1228-1-11 47 
AND SIMPLEFACT bare airframe spiral mode dynamics are adequate 

AND SIMPLEFACT open loop aircraft dynamics are adequate 

AND SIMPLEFACT system has been compared with the specifications 

AND SIMPLEFACT open loop aircraft spec comparison is complete 

SHARED ATTRIBUTE bare airframe dutch roll damping ratio assessment IS adequate 

AND ATTRIBUTE bare airframe dutch roll damping ratio assessment IS too low 

AND ATTRIBUTE bare airframe dutch roll natural frequency IS adequate 

AND ATTRIBUTE bare airframe roll subsidence mode time constant assessment IS adequate 

AND ATTRIBUTE bare airframe roll subsidence mode time constant assessment IS too high 

.................................................................. 

! "PRSPCTUS. FCT" 

! 

! FACTS for FCS PROSPECTUS EXPERT ( PRSPCTUS ) 

! Externally defined facts used in PRSPCTUS 

! ATTRIBUTE Degrees of freedom for control ARE lateral directional axes 

! Facts defined in PRSPCTUS 

AND SIMPLEFACT yaw damper is a candidate loop 

AND SIMPLEFACT roll damper is a candidate loop 

AND SIMPLEFACT sideslip to rudder is a candidate loop 

AND SIMPLEFACT lateral acceleration to rudder is a candidate loop 

AND SIMPLEFACT pitch rate to elevator is a candidate loop 

AND SIMPLEFACT candidate loops have been identified 

AND SIMPLEFACT Candidate loops have been reported 

AND SIMPLEFACT candidate architectures have been identified 

AND SIMPLEFACT RD&YD is a candidate architecture 

AND SIMPLEFACT RD&B-DR is a candidate architecture 

AND SIMPLEFACT RDWY-DR is a candidate architecture 

AND SIMPLEFACT Candidate architectures have been ranked 

AND SIMPLEFACT Prospectus for control has been defined 

SHARED ATTRIBUTE bare airframe roll mode time constant assessment IS adequate 

AND ATTRIBUTE bare airframe roll mode time constant assessment IS too high 

AND ATTRIBUTE First architecture for consideration IS RD&YD 

AND ATTRIBUTE Second architecture for consideration IS RD&B DR 

AND ATTRIBUTE Third architecture for consideration IS RDUY-DR - 

! Initial values of shared attributes 

! AND ATTRIBUTE bare airframe roll mode time constant assessment IS: 

! no assessment 

! AND ATTRIBUTE First architecture for consideration IS undefined 

! AND ATTRIBUTE Second architecture for consideration IS undefined 

! AND ATTRIBUTE Third architecture for consideration IS undefined 

.................................................................. 

TR-1228-1-11 48 
! "ARCH. FCT" 

! 

! FACTS for ARCHITECTURE SELECTION EXPERT (ARCH I 

! Externally defined facts used in ARCH 

! ATTRIBUTE Degrees of freedom for control ARE lateral directional axes 

! ATTRIBUTE First architecture for consideration IS RD&YD 

! ATTRIBUTE RD&YD assessment IS no assessment 

! ATTRIBUTE RD&YD assessment IS assessed and inadequate 

! Facts defined in ARCH 

SHARED SIMPLEFACT Current architecture has been selected 

AND SIMPLEFACT Selection of current architecture has been completed 

AND SIMPLEFACT First loop to design has been specified 

SHARED ATTRIBUTE Current architecture IS RD&YD 

AND ATTRIBUTE Current architecture IS RD&B-DR 

AND ATTRIBUTE Current architecture IS RD&AY-DR 

AND ATTRIBUTE First loop to design IS yaw damper 

AND ATTRIBUTE First loop to design IS roll damper 

AND ATTRIBUTE First loop to design IS B-DR 

AND ATTRIBUTE First loop to design IS AY-DR 

! Initial values of attributes 

! .AND ATTRIBUTE Current architecture IS undefined 

! AND ATTRIBUTE First loop to design IS undefined 

.................................................................. 

! "DESIGN. FCT" 

! 

! FACTS for FCS LOOP DESIGN EXPERT (DESIGN 1 

! Externally defined facts used in DESIGN 

! Yaw damper loop has been designed 

! Current architecture IS RD&YD 

! First loop to design IS yaw damper 

! Yaw damper loop assessment IS assessed and inadequate 

! Yaw damper loop assessment IS assessed and adequate 

! 

! Roll damper loop assessment IS assessed and adequate 

Roll damper loop assessment IS assessed and inadequate 

! Facts defined in DESIGN 

SHARED SIMPLEFACT Current loop has been specified 

AND SIMPLEFACT Current loop connections are set for design 

TR-1228-1-11 49 
AND SIMPLEFACT Current system design model is setup 

AND SIMPLEFACT Current loop must be designed 

AND SIMPLEFACT Current architecture has been designed 

SHARED ATTRIBUTE Current loop IS yaw damper 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

AND ATTRIBUTE 

Current loop IS roll damper 

Current loop IS B-DR 

Current loop IS AY-DR 

Yaw damper loop connection IS open 

Roll damper loop connection IS open 

Sideslip to rudder loop connection IS open 

Lateral acceleration to rudder loop connection IS open 

Yaw damper loop connection IS closed 

Roll damper loop connection IS closed 

Sideslip to rudder loop connection IS closed 

Lateral acceleration to rudder loop connection IS closed 

RD&YD assessment IS assessed and inadequate 

RD&YD assessment IS assessed and adequate 

! Initial values of attributes 

! AND ATTRIBUTE Current loop IS undefined 

! AND ATTRIBUTE RD&YD assessment IS no assessment 

!. ............................................................... 

! "YAWDMPR . FCT" 

! YAW DAMPER EXPERT (YAWDMPR) 

! Externally defined facts used in YAWDMPR 

Specify loop gain directly 

Loop gain has been specified directly 

Examine Root Locus to set the gain 

Loop gain has been specified from root locus 

Examine Bode Siggy to set the gain 

Loop gain has been specified from Bode Siggy 

Loop gain is defined 

Terminate gain selection 

Return to yawdamper module 

! Aircraft classification IS Class IV 

! dutch roll damping ratio assessment IS too low 

! dutch roll damping ratio assessment IS adequate 

SHARED NUMERIC Wrs 

AND NUMERIC Wd 

! Facts Defined in YAWDMPR 

TR-1228-1-11 50 
SHARED SIMPLEFACT Perform complete yaw damper design 

AND SIMPLEFACT Define yaw damper feedback equalization 

AND SIMPLEFACT Define yaw damper gain 

AND SIMPLEFACT Yaw damper measurement query has been made 

AND SIMPLEFACT Yaw damper type has been determined 

AND SIMPLEFACT Yaw damper measurements are adequate 

AND SIMPLEFACT Aircraft operation is limited to low AOA 

AND SIMPLEFACT Aircraft operation is restricted to low AOA 

AND SIMPLEFACT Yaw damper measurement query has been made 

AND SIMPLEFACT Yaw damper measurements have been defined 

AND SIMPLEFACT Rate gyro tilt angle has been queried 

AND SIMPLEFACT Rate gyro tilt angle has been defined 

AND SIMPLEFACT Stability axis yaw damper should be designed 

AND SIMPLEFACT Measurement blending coefficients have been queried 

AND SIMPLEFACT Yaw damper feedback signal has been defined 

AND SIMPLEFACT Basic feedback transfer function has been obtained 

AND SIMPLEFACT rfldr complex dipole is well separated 

AND SIMPLEFACT Complex dipole is suitable for a yaw damper 

AND SIMPLEFACT rfldr pole zero configuration has been examined 

AND SIMPLEFACT Yaw damper washout must be reported 

AND SIMPLEFACT Yaw damper washout is defined 

AND SIMPLEFACT Yaw damper open loop transfer function has been created 

AND SIMPLEFACT Gain selection must be performed 

AND SIMPLEFACT yaw damper gain is defined 

AND SIMPLEFACT Yaw damper loop has been designed 

AND SIMPLEFACT a yaw damper is to be designed 

! 

! 

! 

! 

AND SIMPLEFACT yaw damper is ready for assessment 

AND SIMPLEFACT Current system assessment model is setup 

AND SIMPLEFACT requirement comparison is complete 

AND SIMPLEFACT System dynamics must be obtained 

AND SIMPLEFACT System dynamics have been obtained 

AND SIMPLEFACT System dynamics have been obtained 

AND SIMPLEFACT System poles and zeros must be identified 

AND SIMPLEFACT System poles and zeros have been identified 

AND SIMPLEFACT Yaw damper is ready for assessment 

AND SIMPLEFACT Yaw damper open loop transfer function has been generated 

AND SIMPLEFACT Yaw damper open loop transfer function has been transmitted 

AND SIMPLEFACT Yaw damper assessment dynamics have been generated 

AND SIMPLEFACT Yaw damper assessment dynamics have been transmitted 

AND SIMPLEFACT Yaw damper dynamics are ready for assessment 

AND SIMPLEFACT previous design has been discarded 

AND SIMPLEFACT previous $aw damper measurement has been discarded 

AND SIMPLEFACT previous yaw damper washout has been discarded 

AND SIMPLEFACT previous yaw damper gain has been discarded 

. 

SHARED ATTRIBUTE Yaw damper measurement IS Yaw rate 

AND ATTRIBUTE Yaw damper measurement IS roll rate 

AND ATTRIBUTE Yaw damper type IS Yaw roll type 

AND ATTRIBUTE Yaw damper type IS Yaw only type 

AND ATTRIBUTE Yaw damper loop assessment IS assessed and inadequate 

AND ATTRIBUTE Yaw damper loop assessment IS assessed and adequate 

TR-1228-1-11 51 
SHARED NUMERIC Rate gyro tilt angle 

AND NUMERIC Yaw rate blending coefficient 

AND NUMERIC Roll rate blending coefficient 

AND NUMERIC Yaw damper washout inverse time constant 

AND NUMERIC Yaw damper washout time constant 

AND NUMERIC yaw damper gain 

AND NUMERIC N1 

AND NUMERIC N2 

AND NUMERIC N4 

AND NUMERIC N3 

AND NUMERIC N5 

AND NUMERIC N6 

AND NUMERIC N7 

SHARED STRING S1 

AND STRING S2 

................................................................. 

! "ROLLDMPR . FCT" 

! 

! ROLL DAMPER EXPERT (ROLLDMPR) 

! Externally defined facts used in ROLLDMPR 

! 

! 

! 

! 

! 

! 

! 

! 

! 

I 

Specify loop gain directly 

Loop gain has been specified directly' 

Examine Root Locus to set the gain 

Loop gain has been specified from root locus 

Examine Bode siggy to set the gain 

Loop gain has been specified from Bode Siggy 

Loop gain has been specified 

Loop gain is defined 

Terminate gain selection 

Return to calling module 

! roll subsidence mode time constant assessment IS too high 

! roll subsidence mode time constant assessment IS adequate 

! loop gain 

! Facts defined in ROLLDMPR 

SHARED SIMPLEFACT Define roll damper feedback equalization 

AND SIMPLEFACT Define lead time constant 

AND SIMPLEFACT Define lag time constant 

AND SIMPLEFACT Define roll damper gain 

AND SIMPLEFACT Roll damper lead inverse time constant has been defined 

AND SIMPLEFACT Roll damper lag inverse time constant has been defined 

AND SIMPLEFACT Define roll damper feedback equalization 

AND SIMPLEFACT Pure gain roll damper O.L. transfer function is generated 

TR-1228-1-11 52 
AND SIMPLEFACT Pure gain roll damper has standard root locus topology 

AND SIMPLEFACT Roll damper requires lead equalization 

AND SIMPLEFACT Dutch roll locus goes to rigid body zero 

AND SIMPLEFACT Pure gain roll damper root locus has been examined 

AND SIMPLEFACT Roll damper requires lag equalization 

AND SIMPLEFACT Roll damper feedback equalization has been defined 

AND SIMPLEFACT Roll damper open loop transfer function is created 

AND SIMPLEFACT Gain selection must be performed 

AND SIMPLEFACT roll damper gain is defined 

AND SIMPLEFACT roll damper loop has been designed 

AND SIMPLEFACT roll damper is ready for assessment 

AND SIMPLEFACT Current system assessment model is setup 

AND SIMPLEFACT requirement comparison is complete 

! System dynamics must be obtained 

! System dynamics have been obtained 

! System poles and zeros must be identified 

! System poles and zeros have been identified 

AND SIMPLEFACT Roll damper is ready for assessment 

! System requirement check has been made 

AND SIMPLEFACT Pure gain roll damper OLTF has been generated 

AND SIMPLEFACT Roll damper open loop transfer function has been generated 

AND SIMPLEFACT Roll damper open loop transfer function has been transmitted 

AND SIMPLEFACT Roll damper assessment dynamics have been generated 

AND SIMPLEFACT Roll damper assessment dynamics have been transmitted 

AND SIMPLEFACT Roll damper dynamics are ready for assessment 

. 

SHARED ATTRIBUTE Roll damper loop assessment IS assessed and inadequate 

AND ATTRIBUTE Roll damper loop assessment IS assessed-and adequate 

SHARED NUMERIC Roll damper lag inverse time constant 

AND NUMERIC Roll damper lead inverse time constant 

AND NUMERIC Roll damper gain 

AND NUMERIC N21 

AND NUMERIC N22 

AND NUMERIC N23 

................................................................. 

! "ASSESS. FCT" 

! 

! FACTS for AIRCRAFT DYNAMICS ASSESSMENT (ASSESS) 

! Externally defined facts used in ASSESS 

! requirements are set for the current case 

! dutch roll damping ratio spec 

! roll subsidence mode inverse time constant 

! Roll subsidence mode time constant spec 

+ ! dutch roll damping ratio 

b 

! ATTRIBUTE Current loop 

TR-1228-1-11 53 
! Facts defined in ASSESS 

SHARED SIMPLEFACT dutch roll damping ratio has been assessed 

AND SIMPLEFACT dutch roll mode dynamics are adequate 

AND SIMPLEFACT dutch roll mode has been compared with the requirements 

AND SIMPLEFACT roll mode time constant has been assessed 

AND SIMPLEFACT roll subsidence mode dynamics are adequate 

AND SIMPLEFACT roll subsidence mode has been assessed 

AND SIMPLEFACT modal dynamics are adequate 

AND SIMPLEFACT system has been compared with the requirements 

AND SIMPLEFACT requirement comparison is complete 

SHARED ATTRIBUTE dutch roll damping ratio assessment IS adequate 

AND ATTRIBUTE dutch roll damping ratio assessment IS too low 

AND ATTRIBUTE roll subsidence mode time constant assessment IS adequate 

AND ATTRIBUTE roll subsidence mode time constant assessment IS too high 

SHARED NUMERIC spiral mode inverse time constant 

AND NUMERIC roll subsidence mode inverse time constant 

AND NUMERIC Dutch roll damping ratio 

AND NUMERIC Dutch roll natural frequency 

.................................................................. 

! "GAINSEL. FCT" 

! Loop Gain Selection Expert (GAINSEL) 

! Externally defined facts used in GAINSEL 

! Current loop IS Yaw damper 

! Current loop IS Roll damper 

! Facts defined in GAINSEL 

SHARED SIMPLEFACT Specify loop gain directly 

AND SIMPLEFACT Loop gain has been specified directly 

AND SIMPLEFACT Examine Root Locus to set the gain 

AND SIMPLEFACT Loop gain has been specified from root locus 

AND SIMPLEFACT Examine Bode siggy to set the gain 

AND SIMPLEFACT Loop gain has been specified from Bode Siggy 

AND SIMPLEFACT Loop gain has been specified 

AND SIMPLEFACT Loop gain is defined 

AND SIMPLEFACT Terminate gain selection 

AND SIMPLEFACT Return to calling module 

AND SIMPLEFACT Yaw damper gain is defined 

AND SIMPLEFACT Roll damper gain is defined 

SHARED NUMERIC Loop gain 

! ................................................................ 

! 

TR-1228-1-11 54 
! Augmented Aircraft Pole and Zero Identification (ROOTID) 

I 

I ! Externally defined facts used in ROOTID 

1 ! 

! 

! 

! 

! 

! 

! 

! 

! 

* 

Current architecture IS RD&YD 

Roll damper loop connection IS open 

Roll damper loop connection IS closed 

Yaw damper loop connection IS open 

Yaw damper loop connection IS closed 

Current loop IS Yaw damper 

Current loop IS Roll damper 

Calling expert IS YAWDMPR expert 

Calling expert IS ROLLDMPR expert 

! Facts defined in ROOTID 

SHARED SIMPLEFACT System poles and zeros have been identified 

AND SIMPLEFACT System identification transfer function has been read 

AND SIMPLEFACT System poles and zeros have been identified 

AND SIMPLEFACT System poles are identified 

AND SIMPLEFACT Return to calling expert 

SHARED NUMERIC ITS' . 

AND NUMERIC ITr' 

AND NUMERIC Zd' 

AND NUMERIC Wd' 

AND NUMERIC ITS" 

AND NUMERIC ITr" 

AND NUMERIC Zd" 

AND NUMERIC Wd" 

.................................................................. 

! Creation of Augmented Aircraft Model (SYSMOD) 

! Externally defined facts used in SYSMOD 

! Roll rate blending coefficient 

! Yaw rate blending coefficient 

! Roll damper gain 

! Roll damper lead inverse time constant 

! Roll damper lag inverse time constant 

! yaw damper gain 

! Yaw damper washout inverse time constant 

I Facts defined in SYSMOD 

SHARED SIMPLEFACT System model must be generated 

AND SIMPLEFACT FCS parameters are set 

AND SIMPLEFACT System model has been generated 

AND'SIMPLEFACT Return to calling expert 

TR-1228-1-11 55 
SHARED ATTRIBUTE Expert requesting SYSMOD IS DESIGN expert 

AND ATTRIBUTE Expert requesting SYSMOD IS YAWDMPR expert 

AND ATTRIBUTE Expert requesting SYSMOD IS ROLLDMPR expert 

.................................................................. 

! 

! Transfer Function Extraction (TFEXT) 

! Facts defined in TFEXT 

SHARED SIMPLEFACT Return to calling expert 

AND SIMPLEFACT System model has been generated 

AND SIMPLEFACT Specified system transfer function has been transmitted 

AND SIMPLEFACT Return to calling expert 

SHARED ATTRIBUTE Calling expert IS YAWDMPR expert 

AND ATTRIBUTE Calling expert IS ROLLDMPR expert 

SHARED STRING Transfer function $$g filename 

I 

TR-1228-1-11 56 
MU LTI.SH R 

. 

TR-1228-1-11 57 
! "MULTI.SHR" 

! 

! Multiple Attributes Declarations 

! 

! The Multiple Attributes Declaration is stored in the "include" file named 

! "MULTI . SHR" . 

I 

MULTI Yaw damper measurement 

I TR-1228-1-11 58 
EXHAUSTKSHR t 

. 

TR-1228-1-11 59 
! "EXHAUSTV. SHR" 

! 

! Exhaustive Simplefacts Declarations 

! 

! The EXHAUSTIVE SIMPLEFACTS Declaration is stored in the "include" file 

! 

! time . ................................................................... 

named "EXHAUSTV.SHR". No simplefacts are declared to EXHAUSTIVE at this 

! AIRCRAFT DEFINITION (AIRCRAFT) 

EXHAUSTIVE Aircraft has been designated 

AND Aircraft has been classified 

AND Degrees of freedom for control have been defined 

AND aircraft basic data file has been read 

AND aileron actuator bandwidth has been specified 

AND rudder actuator bandwidth has been specified 

AND aileron channel effective time delay has been specified 

AND rudder channel effective time delay has been specified 

AND aileron actuator transfer function has been generated 

AND rudder actuator transfer function has been generated 

AND aileron time delay transfer function has been generated 

AND rudder time delay transfer function has been generated 

AND Actuator dynamics have been defined 

AND High frequency dynamics have been defined 

AND Aircraft basic data has been obtained 

AND Aircraft basic data must be obtained 

! ................................................................. 

I ! FLIGHT CONDITION DEFINITION (FLTCOND) 

AND Flight and trim conditions have been obtained 

AND Stability and control derivatives have been obtained 

AND State matrix calculations have been obtained 

AND Bare airframe dynamics have been obtained 

AND Literal approximate factors have been obtained 

AND Complete aircraft data has been obtained 

AND Requirements must be set for the current case 

................................................................. 

I ! AIRCRAFT DYNAMICS REQUIREMENTS SETUP (SPECSET) 

AND Dutch roll damping ratio spec is set 

AND Dutch roll natural frequency spec is set 

AND Dutch roll mode specs are set 

AND Roll subsidence mode time constant spec is set 

AND Roll subsidence mode specs are set 

AND Dutch roll mode specs are set 

AND Lateral directional specs are set 

AND Requirements are set for the current case 

TR-1228-1-11 60 
................................................................. 

! FACTS for OPEN LOOP AIRCRAFT ASSESSEMENT (ASSESSOL) 

AND Complete aircraft data has been obtained 

AND open loop aircraft model is setup 

AND open loop aircraft dynamics have been obtained 

AND open loop aircraft poles and zeros have been identified 

AND open loop aircraft spec comparison is complete 

AND open loop aircraft dynamics are adequate 

AND open loop aircraft assessment is complete 

.................................................................. 

! BARE AIRCRAFT DYNAMICS SPECIFICATION CHECKER (SPECHKOL) 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

bare airframe dutch roll damping ratio has been assessed 

bare airframe dutch roll mode dynamics are adequate 

bare airframe dutch roll mode has been assessed 

bare airframe roll mode time constant has been assessed 

bare airframe roll subsidence mode dynamics are adequate 

bare airframe roll subsidence mode has been assessed 

bare airframe spiral mode dynamics are adequate 

open loop aircraft dynamics are adequate 

system has been compared with the specifications 

open loop aircraft spec comparison is complete . .................................................................. 

! FACTS for FCS PROSPECTUS EXPERT ( PRSPCTUS I 

AND yaw damper is a candidate loop 

AND roll damper is a candidate loop 

AND sideslip to rudder is a candidate loop 

AND lateral acceleration to rudder is a candidate loop 

AND pitch rate to elevator is a candidate loop 

AND candidate loops have been identified 

AND Candidate loops have been reported 

AND candidate architectures have been identified 

AND RD&YD is a candidate architecture 

AND RD&B-DR is a candidate architecture 

AND RD&AY-DR is a candidate architecture 

AND Candidate architectures have been ranked 

AND Prospectus for control has been defined 

.................................................................. 

! FACTS for ARCHITECTURE SELECTION EXPERT (ARCH) 

AND Current architecture has been selected 

AND Selection of current architecture has been completed 

TR-1228-1-11 61 
I AND First loop to design has been specified 

I .................................................................. 

! FACTS for FCS LOOP DESIGN EXPERT (DESIGN) 

AND Current loop has been specified 

AND Current loop connections are set for design 

AND Current system design model is setup 

AND Current loop must be designed 

AND Current architecture has been designed 

................................................................. 

I 

! FACTS for YAWDMPR 

AND Perform complete yaw damper design 

AND Define yaw damper feedback equalization 

AND Define yaw damper gain 

AND Yaw damper measurement query has been made 

AND Yaw damper type has been determined 

AND Yaw damper measurements are adequate 

! AND Aircraft operation is limited to low AOA 

AND Aircraft operation is restricted to low AOA 

AND Yaw damper measurement query has been made 

AND Yaw damper measurements have been defined 

AND Rate gyro tilt angle has been queried 

AND Rate gyro tilt angle has been defined 

AND Stability axis yaw damper should be designed 

AND Measurement blending coefficients have been queried 

AND Yaw damper feedback signal has been defined 

AND Basic feedback transfer function has been obtained 

AND rfldr complex dipole is well separated 

AND Complex dipole is suitable for a yaw damper 

AND rfldr pole zero configuration has been examined 

AND Yaw damper washout must be reported 

AND Yaw damper washout is defined 

AND Yaw damper open loop transfer function has been created 

AND Gain selection must be performed 

AND yaw damper gain is defined 

AND Yaw damper loop has been designed 

AND a yaw damper is to be designed 

AND previous design has been discarded 

AND previous yaw damper measurement has been discarded 

AND previous yaw damper washout has been discarded 

AND previous yaw damper gain has been discarded 

AND yaw damper is ready for assessment 

AND Current system assessment model is setup 

AND requirement comparison is complete 

AND System dynamics must be obtained 

AND System dynamics have been obtained 

AND System dynamics have been obtained 

. 

TR-1228-1-11 62 
AND System poles and zeros must be identified 

AND System poles and zeros have been identified 

AND Yaw damper is ready for assessment 

!. ............................................................... 

! ROLL DAMPER EXPERT (ROLLDMPR) 

AND Define roll damper feedback equalization 

AND Define lead time constant 

AND Define lag time constant 

AND Define roll damper gain 

AND Roll damper lead inverse time constant has been defined 

AND Roll damper lag inverse time constant has been defined 

AND Define roll damper feedback equalization 

AND Pure gain roll damper O.L. transfer function is generated 

AND Pure gain roll damper has standard root locus topology 

AND Roll damper requires lead equalization 

AND Dutch roll locus goes to rigid body zero 

AND Pure gain roll damper root locus has been examined 

AND Roll damper requires lag equalization 

AND Roll damper feedback equalization has been defined 

AND Roll damper open loop transfer function is created 

AND Gain selection must be performed 

AND roll damper gain is defined 

AND roll damper loop has been designed 

AND roll damper is ready for assessment 

AND Current system assessment model is setup 

AND requirement comparison is complete 

! 

! 

! 

! 

AND Roll damper is ready for assessment 

! 

System dynamics must be obtained 

System dynamics have been obtained 

System poles and zeros must be identified 

System poles and zeros have been identified 

System requirement check has been made 

................................................................. 

I 

! FACTS for AIRCRAFT DYNAMICS ASSESSMENT (ASSESS) 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

dutch roll damping ratio has been assessed 

dutch roll mode dynamics are adequate 

dutch roll mode has been compared with the requirements 

roll mode time constant has been assessed 

roll subsidence mode dynamics are adequate 

roll subsidence mode has been assessed 

modal dynamics are adequate 

system has been compared with the requirements 

requirement comparison is complete 

.................................................................. 

TR- 1228 - 1 -.I1 63 
! "GAINSEL. FCT" 

AND Specify loop gain directly 

AND Loop gain has been specified directly 

AND Examine Root Locus to set the gain 

AND Loop gain has been specified from root locus 

AND Examine Bode siggy to set the gain 

AND Loop gain has been specified from Bode Siggy 

AND Loop gain has been specified 

AND Loop gain is defined 

AND Terminate gain selection 

AND Return to calling module 

AND Yaw damper gain is defined 

AND Roll damper gain is defined 

TR-1228-1-11 64 
TR-1228-1-11 

INlTAll' 

65 
! "INITATT" 

! 

! Initialization of Attribute Values 

! 

! The initial attribute values are stored in the "include" file named 

I INITATT" .................................................................. 

! FACTS for FCS LOOP DESIGN EXPERT (DESIGN) 

AND Yaw damper loop connection IS open 

AND Roll damper loop connection IS open 

AND Sideslip to rudder loop connection IS open 

AND Lateral acceleration to rudder loop connection IS open 

................................................................. 

! FACTS for (ARCH 1 

AND RD&YD assessment IS assessed and inadequate CF 0 

AND RD&YD assessment IS assessed and adequate CF 0 

................................................................. I 

AND Yaw damper loop assessment IS assessed and inadequate CF 0 

AND Yaw damper loop assessment IS assessed and adequate CF 0 

. ................................................................. 

AND Roll damper loop assessment IS assessed and inadequate CF 0 

AND Roll damper loop assessment IS assessed and adequate CF 0 

TR-1228-1-11 66 
GENERATE.PRL 

TR-1228-141 67 
! "GENERATE" 

! 

TITLE FLIGHT CONTROL SYSTEM GENERATOR (GENERATE) DISPLAY 

This Expert functions as an executive to assist in managing the overall flight 

control design process. 

To continue, press F3 

SYSTEMS TECHNOLOGY, INC Hawthorne, CA 

Copyright (C) 1988 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

! 

$SHAREFCT.SHR 

! 

! 

! Data Type Declarations 

! 

! 

! Parameter Initialization Statements 

...................................................... * '.' * * * * * * - 

................................................................ I 

INIT yaw damper loop has been designed CF 0 

AND roll damper loop has been designed CF 0 

AND B DR loop has been designed CF 0 

AND AT DR loop has been designed CF 0. 

AND Roil damper lead inverse time constant := 2000. 

AND Roll damper lag inverse time constant := 2000. 

AND Roll damper gain :- 0.0 

AND Yaw damper gain :=- 0.0 

AND Yaw damper washout inverse time constant := .0001 

AND g := 32.2 ! Acceleration due to gravity, ftlseclsec 

! Initialization of Attribute Values 

! 

................................................................. 

! FACTS for FCS LOOP DESIGN EXPERT (DESIGN) 

TR-1228-1-11 68 
INIT Yaw damper loop connection IS open 

AND Roll damper loop connection IS open 

AND Sideslip to rudder loop connection IS open 

AND Lateral acceleration to rudder loop connection IS open 

................................................................. 

! FACTS for (ARCH) 

AND RD&YD assessment IS assessed and inadequate CF 0 

AND RD&YD assessment IS assessed and adequate CF 0 

................................................................. 

AND Yaw damper loop assessment IS assessed and inadequate CF 0 

AND Yaw damper loop assessment IS assessed and adequate CF 0 

!.. ............................................................... 

AND Roll damper loop assessment IS assessed and inadequate CF 0 

AND Roll damper loop assessment IS assessed and adequate CF 0 

............................................................... 

! 

! Control Element Selectors 

THRESHOLD - 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$ExHAUSTv. SHR 

!............................................................. 

! 

I Multivalued Attribute Declarations 

! 

I The "MULTI" Declaration of multivalued attributes is stored in the 

! "include" file named "MULTI.SHR" and combined with this knowledge 

! base during compilation. 

$MULTI . SHR 

.............................................................. 

! 

! 

! Goal Outline 

1. Previous session data restoration option exercised 

1.1. Specify a new aircraft for FCS design 

1.1.1 Aircraft basic data must be obtained 

TR-1228-1-11 69 
1.2. Specify a new flight condition for the current aircraft 

1.2.1 Complete aircraft data must be obtained 

1.3. Select an FCS architecture for design 

1.3.1 Current architecture must be selected 

1.4. Select a loop for design within the current architecture 

1.4.1 Current loop must be selected 

1.5. Store current design data on file 

1.5.1 Current context must be stored 

! 

! Rules 

RULE for restoring previous context 

IF ASK Previous design data should be restored 

AND Previous design data should be restored 

THEN Previous session data restoration option exercised 

AND CONTEXT RESTORE C:\FCSXPRT\LASTDSGN.CTX 

AND DISPLAY context restore 

ELSE Previous session data restoration option exercised 

RULE For obtaining aircraft basic data 

IF Specify a new aircraft for FCS design 

THEN Aircraft basic data must be obtained 

AND FORGET Aircraft has been designated 

AND FORGET Aircraft has been classified 

AND FORGET Degrees of freedom for control have been defined 

AND FORGET aileron actuator bandwidth has been specified 

AND FORGET rudder actuator bandwidth has been specified 

AND FORGET aileron channel effective time delay has been specified 

AND FORGET rudder channel effective time delay has been specified 

AND FORGET aileron actuator transfer function has been generated 

AND FORGET rudder actuator transfer function has been generated 

AND FORGET aileron time delay transfer function has been generated 

AND FORGET rudder time delay transfer function has been generated 

AND FORGET Actuator dynamics have been defined 

AND FORGET High frequency dynamics have been defined 

AND FORGET aircraft basic data file has been read 

AND FORGET Aircraft basic data has been obtained 

AND FORGET Aircraft classification 

AND FORGET aircraft type 

AND FORGET Degrees of freedom for control 

AND CHAIN C:\FCSXPRT\AIRCRAFT 

RULE For obtaining complete aircraft data 

IF Specify a new flight condition for the current'aircraft 

AND Aircraft basic data has been obtained 

THEN Complete aircraft data must be obtained 

AND FORGET Flight and trim conditions have been obtained 

TR-1228-1- I1 70 
AND FORGET Stability and control derivatives have been obtained 

AND FORGET Bare airframe dynamics have been obtained 

AND FORGET Literal approximate factors have been obtained 

AND FORGET Complete aircraft data has been obtained 

, AND FORGET State matrix calculations have been obtained 

I 

I AND FORGET Requirements must be set for the current case 

* AND FORGET Flight phase category 

AND CHAIN C:\FCSXPRT\FLTCOND 

f RULE for selecting the current FCS architecture 

IF Select an FCS architecture for design 

AND Prospectus for control has been defined 

THEN Current architecture must be selected 

AND FORGET Current architecture has been selected 

AND FORGET Selection of current architecture has been completed 

AND FORGET First loop to design has been specified 

AND CHAIN C:\FCSXPRT\ARCH 

RULE for selecting the current loop for design 

IF Select a loop for design within the current architecture 

AND Selection of current architecture has been completed 

THEN Current loop must be selected 

AND FORGET Current loop has been specified 

AND FORGET Current loop connections are set for design 

AND FORGET Current system design model'is setup 

AND FORGET Current loop must be designed 

AND FORGET Current architecture has been designed 

AND CHAIN C:\FCSXPRT\DESIGN 

RULE for saving current context 

IF Store current design data on file 

AND ASK design data set is to be saved 

AND design data set is to be saved 

AND FORGET Specify a new aircraft for FCS design 

AND FORGET Aircraft basic data must be obtained 

AND FORGET Specify a new flight condition for the current aircraft 

AND FORGET Complete aircraft data must be obtained 

AND FORGET Select an FCS architecture for design 

AND FORGET Current architecture must be selected 

AND FORGET Select a loop for design within the current architecture 

AND FORGET Current loop must be selected 

AND FORGET Store current design data on file 

AND FORGET Current context must be stored 

THEN Current context must be stored 

AND CONTEXT SAVE C:\FCSDAT\LASTDSGN.CTX 

AND CYCLE t AND DISPLAY context message 

!- 

! 

I Information Display Text 

TR-1228-1-11 71 
DISPLAY context restore 

The data set for the previous design session (or the last session saved) has 

now been restored so that the design work can be continued. 

To continue, press F2 

DISPLAY context message 

The complete data set for this design session has now been saved for future 

use on the file "LASTDSGN.CTX". 

To continue, press F2 

! 

END 

TR-1228-1-11 72 
AlRCRAFT.PRL 

TR-1228-1 -It 73 
! "AIRCRAFT. PRL" 

! 

TITLE AIRCRAFT DEFINITION (AIRCRAFT) DISPLAY 

This expert assists in the specification of the aircraft for which 

a flight control system is to be designed. This includes obtaining all 

geometric and mass property information which is independent of flight 

condition. 

Note that all previous DATA AND DESIGN RESULTS WILL BE DISCARDED. 

To continue, press F3 

SYSTEMS TECHNOLOGYl INC Hawthorne, CA 

Copyright (C) 1988 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the iiir&deii file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

$SHAREFCT.SHR 

................................................................ 

! 

! Data Type Declarations 

! 

................................................................ 

! 

! Parameter Initialization Statements 

! 

INIT St7-"C : \STI" 

AND St8="CC. EXE" 

AND S t9-"@FORWARD. MAC" 

REINIT St7-"C :\STI" 

AND St8-"CC. EXE" 

AND S t9-"@FORWARD. MAC" 

............................................................... 

! 

! Control Element Selectors 

THRESHOLD * 100 

CONFIDENCE OFF 

TR-1228-1-11 74 
GOALSELECT ON 

UNKNOWN CONTINUE 

$ExHAUSTv. SHR 

.............................................................. 

! 

! Multiattributed Objects Declarations 

! 

! "include" file named "MULTI.SHR" and combined with this knowledge base 

! during compilation. 

c ! The "MULTI" Declaration of multiattributed objects is stored in the 

$MULTI . SHR 

.............................................................. 

! 

! Goal Outline 

1 

1. Aircraft has been designated 

1.1 Aircraft has been classified 

1.1.1 Degrees of freedom for control have been defined 

1.1.1.1 Aircraft basic data has been obtained 

! 

! 

! Rules 

! 

RULE fbr identifying the aircraft 

IF ASK Aircraft designation 

THEN Aircraft has been designated 

RULE for aircraft classification 

IF Aircraft classification IS Class I 

OR Aircraft classification IS Class I1 

OR Aircraft classification IS Class I11 

OR Aircraft classification IS Class IV 

THEN Aircraft has been classified 

RULE for Class IV aircraft 

IF aircraft type IS Fighter 

OR aircraft type IS Interceptor 

OR aircraft type IS Attack 

OR aircraft type IS Tactical reconnaissance 

OR aircraft type IS Observation 

OR aircraft type IS Trainer for Class IV aircraft 

OR aircraft type IS generic high maneuverability aircraft 

THEN Aircraft has been classified 

AND Aircraft classification IS Class IV 

RULE for defining Degrees of freedom for control 

IF Degrees of freedom for control ARE lateral directional axes 

75 TR-1228-1-11 
OR Degrees of freedom for control ARE longitudinal axes 

THEN Degrees of freedom for control have been defined 

RULE for reading in aircraft basic data file 

IF Degrees of freedom for control have been defined 

AND DISPLAY basic data read 

AND READ C:\FCSDAT\ACDATA.PRM 

DATA Aircraft Kind 

DATA Aircraft Class 

DATA Planform Area 

DATA Mean Aerodynamic Cord 

DATA Wing Span 

DATA Thrust Inclination 

DATA Weight 

DATA X Center of Gravity Mac 

DATA X Center of Gravity 

DATA Y Center of Gravity 

DATA Z Center of Gravity 

DATA X Moment of Inertia 

DATA Y Moment of Inertia 

DATA 2 Moment of Inertia 

DATA XY Product of Inertia 

DATA XZ Product of Inertia 

DATA YZ Product of Inertia 

THEN aircraft basic data file has been read 

! 

............................................................. I 

! 

! Rules for obtaining actuator and high frequency dynamics 

RULE for obtaining aileron actuator bandwidth 

IF ASK roll control actuator bandwidth 

AND roll control actuator bandwidth > 0 

THEN aileron actuator bandwidth has been specified 

ELSE DISPLAY negative bandwidth 

AND LOOP 

RULE for obtaining rudder actuator bandwidth 

IF ASK rudder actuator bandwidth 

AND rudder actuator bandwidth > 0 

THEN rudder actuator bandwidth has been specified 

ELSE DISPLAY negative bandwidth 

AND LOOP 

RULE for obtaining effective time delay in aileron channel 

IF ASK roll control channel effective time delay 

AND roll control channel effective time delay > 0 

THEN aileron channel effective time delay has been specified 

ELSE DISPLAY negative time delay 

AND LOOP 

TR-1228-1-11 76 
RULE for obtaining effective time delay in aileron channel 

IF ASK rudder channel effective time delay 

AND rudder channel effective time delay > 0 

THEN rudder channel effective time delay has been specified 

ELSE DISPLAY negative time delay 

AND LOOP 

!.. ............................................................... c ! 

! Rules for creating actuator and effective time delay transfer functions 

RULE for generating aileron actuator transfer function 

IF aileron actuator bandwidth has been specified 

THEN aileron actuator transfer function has been generated 

RULE for generating rudder actuator transfer function 

IF rudder actuator bandwidth has been specified 

THEN rudder actuator transfer function has been generated 

RULE for generating aileron effective time delay transfer function 

IF aileron channel effective time delay has been specified 

THEN aileron time delay transfer function has been generated 

RULE for generating rudder effective time delay transfer function 

IF rudder channel effective time delay'has been specified 

THEN rudder time delay transfer function has been generated 

AND ACTIVATE C:\STI\PROCALL.EXE 

SEND St7 

SEND St8 

SEND St9 

SEND roll control actuator bandwidth 

SEND rudder actuator bandwidth 

SEND roll control channel effective time delay 

SEND rudder channel effective time delay 

RULE for definition of actuator dynamics 

IF aileron actuator transfer function has been generated 

AND rudder actuator transfer function has been generated 

THEN Actuator dynamics have been defined 

RULE for definition of high frequency dynamics 

IF aileron time delay transfer function has been generated 

AND rudder time delay transfer function has been generated 

THEN High frequency dynamics have been defined 

.................................................................. 

! 

! Rules for concluding aircraft basic data definition 

RULE for concluding aircraft basic data definition 

IF aircraft basic data file has been read 

AND Actuator dynamics have been defined 

AND High frequency dynamics have been defined 

TR-1228-1-11 77 
THEN Aircraft basic data has been obtained 

AND DISPLAY Aircraft Summary 

AND FORGET Flight and trim conditions have been obtained 

AND FORGET Stability and control derivatives have been obtained 

AND FORGET State matrix calculations have been obtained 

AND FORGET Bare airframe dynamics have been obtained 

AND FORGET Literal approximate factors have been obtained 

AND FORGET Complete aircraft data has been obtained 

AND FORGET Requirements must be set for the current case 

AND FORGET Flight phase category 

AND CHAIN C:\FCSXPRT\FLTCOND 

! 

I 

! Information Display Text 

DISPLAY basic data read 

Basic aircraft data, which is independent of flight condition, will now be read 

from file. 

To continue, press F2 

DISPLAY Aircraft Summary 

The basic aircraft data, independent of flight condition, has been obtained 

for the [Degrees of freedom for control] of: 

Aircraft - [Aircraft designation] 

Type - [Aircraft type] 

Mil-Spec Class - [Aircraft classification] 

Planform Area 

Cord] 

Wing Span 

Weight 

X Center of Gravity 

Gravity] 

Z Center of Gravity 

Inertia] 

Y Moment of Inertia 

Inertia] 

XY Product of Inertia 

o f Inertia ] 

YZ Product of Inertia 

[Planform Area] Mean Aerodynamic Cord - [Mean Aerodynamic 

[Wing Span] Thrust Inclination - [Thrust Inclination] 

[Weight] X c.g. Mac - [X Center of Gravity Mac] 

[X Center of Gravity] Y Center of Gravity - [Y Center of 

[Z Center of Gravity] X Moment of Inertia - [X Moment of 

[Y Moment of Inertia] Z Moment of Inertia - [Z Moment of 

[XY Product of Inertia] XZ Product of Inertia - [XZ Product 

[YZ Product of Inertia] 

Additional flight condition specific data, such as stability derivatives must 

now be be obtained. 

TR-1228-1-11 78 
To specify the flight condition, press F2 

DISPLAY negative bandwidth 

Bandwidth specifications must be POSITIVE numbers in radians/second. 

To continue, press F2 

DISPLAY negative time delay 

Effective time delays must be POSITIVE numbers in seconds. 

To continue, press F2 

EXPAND Aircraft designation 

Enter a name or designation for the aircraft. 

To continue, press F8 

! 

END 

TR-1228-1-11 79 
! "FLTCOND . PRL" 

! 

TITLE FLIGHT CONDITION DEFINITION (FLTCOND) DISPLAY 

This expert assists in the definition of the flight condition and trim data 

needed for flight control system design. 

information, such as stability derivatives, which are functions of flight 

condition. 

This includes obtaining all aircraft 

Note that any previously defined aircraft data, which is dependent on flight 

condition, will.Not be retained. 

To continue, press F3 

SYSTEMS TECHNOLOGY, INC Hawthorne, CA 

Copyright (C) 1988 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! 

! 

! 

$SHAREFCT.SHR 

"SHAREFCT.SHR" and combined with this knowledge base during compilation 

1 

I 

................................................................ 

! 

! 

! Data Type Declarations 

! 

!STRING StlO 

................................................................ 

! 

! Parameter Initialization Statements 

INIT ZERO-0 

AND ONE-1 

AND TWO-2 

AND FOUR-4 

AND SIX-6 

! 

! 

I 

String variables sent to DATOCC to create CC compatible files 

TR-1228-1-11 81 
! 

AND Stl :- "C:\FCSDAT" 

I Name of BASIC file to be converted to CC format 

AND St2 :- "BAREAC.SSM" 

! Program CC filename 

AND St3 :- 'l$$PIOO1l 

Name of directory where the BASIC file that will be converted resides 

! String variables sent to PROCALL program to activate an external program 

! 

AND St7 :- "C:\STI" 

! Name of the external program 

AND St8 :- "CC.EXE" 

! 

AND St15 :- ll@BAREAC.MAC,P1OO,HIOO" 

Subdirectory containing the external program 

Parameters passed to external program 

REINIT ZERO-0 

AND ONE-1 

AND TWO-2 

AND FOUR-4 

AND SIX-6 

! 

! String variables sent to DATOCC to create CC compatible files 

! Name of directory where the BASIC file that will be converted resides 

AND Stl :- "C:\FCSDAT" 

! Name of BASIC file to be converted to CC format 

AND St2 := "BAREAC.SSM" 

' ! Program CC filename 

AND St3 :- I1$$PIOO" 

! String variables sent to PROCALL program to activate an external program 

! 

AND St7 :- "C:\STI" 

! 

AND St8 :- "CC.EXE" 

! 

AND S t15 : = "@BAREAC. MAC, PlOO HlOO" 

Subdirectory containing the external program 

Name of the external program 

Parameters passed to external program 

............................................................... 

! 

! Control Element Selectors 

THRESHOLD - 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV. SHR 

TR-1228-1-11 82 
.............................................................. 

! 

! Multiattributed Objects Declarations 

! 

! The "MULTI" Declaration of multivalued attribute is stored in the 

! "include" file named "MULTI. SHR" and combined with this knowledge base 

! during compilation. 

$MULTI . SHR 

.............................................................. 

! 

! 

! Goal Outline 

1. Flight and trim conditions have been obtained 

1.1.1 State matrix calculations have been obtained 

1.1 Stability and control derivatives have been obtained 

1.1.1.1 Bare airframe dynamics have been obtained 

1.1.1.1.1 Literal approximate factors have been obtained 

1.1.1.1.1.1 Requirements must be set for the current case 

! 

! Rules 

RULE for reading flight and trim data file 

IF Aircraft basic data has been obtained 

AND DISPLAY flight condition data read 

AND READ C:\FCSDAT\FLTCND.PRM 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

DATA 

THEN 

Flight Condition 

Flight Phase 

Flight phase category literal 

Mach Number 

A1 t i tude 

True Airspeed 

Wing Span 

Trim Angle of Attack 

Trim Angle of Sideslip 

Trim Heading 

Trim Pitch Attitude 

Trim Bank Angle 

Trim Flight Path Angle 

Trim Roll Rate 

Trim Pitch Rate 

Trim Yaw Rate 

Trim Turn Rate 

Trim Normal Load Factor 

Trim Lateral Load Factor 

Trim Axial Load Factor 

Flight and trim conditions have been obtained 

AND Uo :- (True Airspeed)*COS(Trim angle of attack/57.3) 

TR-1228-1-13. a3 
ELSE DISPLAY no basic data 

AND CHAIN C:\FCSXPRT\GENERATE 

RULE for reading stability derivative data file 

IF Flight and trim conditions have been obtained 

AND DISPLAY derivative data read 

AND READ C:\FCSDAT\DERIVS.PRM 

DATA Yp 

DATA Lp' 

DATA Np' 

DATA Lp' 

DATA Np' 

DATA Lr' 

DATA Nr' 

DATA YSa# 

DATA LSa' 

DATA NSa' 

DATA YSr# 

DATA LSr' 

DATA N6r' 

DATA Y/3b 

DATA Lp'b 

DATA Np'b 

DATA Lp'b 

DATA Np'b 

DATA Lr'b 

DATA Nr'b 

DATA YSa#b 

- DATA LCa'b 

DATA NSa'b 

DATA YSr#b 

DATA LLr'b 

DATA NSr'b 

THEN Stability and control derivatives have been obtained 

! 

! 

! Defining the state matrix 

! 

! 

RULE for defining bare airframe state matrix elements 

IF Flight and trim conditions have been obtained 

AND stability and control derivatives have been obtained 

THEN State matrix calculations have been obtained 

AND Yv := YBb/True Airspeed 

AND aorad := Trim angle of attack/57.3 

AND Borad := Trim pitch attitude/57.3 

AND SINao := SIN(aorad) 

AND NSINao := -SINao 

~ AND COSao := COS(aorad) 

AND NCOSao := -COSao 

AND GCOSBo := 32.17*COS(Borad)/True Airspeed 

AND TANBo :- TAN(Borad) I 

I 84 

TR-1228-1-11 
! 

! 

RULE for obtaining bare airframe dynamics 

IF Stability and control derivatives have been obtained 

AND DISPLAY open loop dynamics data 

AND WRITE C:\FCSDAT\BAREAC.SSM 

DATA FOUR 

DATA TWO 

DATA TWO 

DATA Yv 

DATA SINao 

DATA NCOSao 

DATA GCOSBo 

DATA YSa#b 

DATA YCr#b 

DATA u'b 

DATA Lp'b 

DATA Lr'b 

DATA ZERO 

DATA LCa'b 

DATA LCr'b 

DATA Np'b 

DATA Np'b 

DATA Nr'b 

DATA ZERO 

DATA NCa'b 

DATA NCr'b 

DATA ZERO 

DATA .ONE 

DATA TANBo 

DATA ZERO 

DATA ZERO 

DATA ZERO 

DATA ZERO 

DATA ONE 

DATA ZERO 

DATA ZERO 

DATA ZERO 

DATA ZERO 

DATA ZERO 

DATA ZERO 

DATA ONE 

DATA ZERO 

DATA ZERO 

DATA ZERO 

! The BASIC file "BAREAC.SSM" (St2) contains the bare airframe 

! 

! 

AND ACTIVATE C:\STI\DATOCC.EXE 

SEND Stl 

SEND St2 

SEND St7 

state space model which will be transmitted to Program CC by DATOCC 

and converted to a state space quadruple named "$$P10O1' (St3) 

TR-1228-1-11 85 
SEND St3 

AND ACTIVATE C:\STI\PROCALL.EXE 

SEND St7 

SEND St8 

SEND St15 

THEN Bare airframe dynamics have been obtained 

AND bare airframe dutch roll damping ratio :- 0.10 ! TEMPORARY 

RULE for obtaining literal approximate factors 

IF Bare airframe dynamics have been obtained 

AND DISPLAY Literal approximate factors 

AND FORGET Literal poles have been enumerated 

AND FORGET Literal factors are defined for bare airframe poles 

AND CHAIN C:\FCSXPRT\LITFAC 

THEN Literal approximate factors have been obtained 

RULE for setting requirements for the design case 

IF Literal approximate factors have been obtained 

! AND DISPLAY requirement setup 

THEN Complete aircraft data has been obtained 

AND Requirements must be set for the current case 

AND FORGET Dutch roll damping ratio spec is set 

AND FORGET Dutch roll natural frequency spec is set 

AND FORGET Dutch roll mode specs are set 

AND FORGET Roll subsidence mode time constant spec is Set 

AND FORGET Roll subsidence mode specs are set 

AND FORGET Dutch roll mode specs are set 

AND FORGET Lateral directional specs are set 

AND FORGET Requirements are set for the current’case 

AND CHAIN C:\FCSXPRT\SPECSET 

AND DISPLAY Aircraft Summary 

! 

! 

! Information Display Text 

DISPLAY no basic data 

An aircraft and its basic data are not presently specified, so the flight 

condition specific data cannot be obtained yet. 

To specify an aircraft, press F2 

DISPLAY flight condition data read 

Flight condition and trim data will now be read from a file. 

To continue, press F2 

TR-1228-1-11 86 
DISPLAY derivative data read 

Flight Condition - [Flight Condition] 

Flight Phase - [Flight Phase] 

Flight phase category - [Flight phase category] 

Mach Number - 

True Airspeed - 

Trim Angle of Attack - 

Angle of Sideslip] 

Trim Heading - 

Attitude ] 

Trim Bank Angle - 

Path Angle] 

Trim Roll Rate - 

Rate] 

Trim Yaw Rate - 

Trim Normal Load Factor - 

Lateral Load Factor] 

Trim Axial Load Factor - 

[Mach Number] Altitude - [Altitude] 

[True Airspeed] Wing Span - [Wing Span] 

[Trim Angle of Attack] Trim Angle of Sideslip - [Trim 

[Trim Heading] Trim Pitch Attitude - [Trim Pitch 

[Trim Bank Angle] Trim Flight Path Angle - [Trim Flight 

[Trim Roll Rate] Trim Pitch Rate - [Trim Pitch 

[Trim Yaw Rate] Trim Turn Rate - [Trim Turn Rate] 

[Trim Normal Load Factor] Trim Lateral Load Factor - [Trim 

[Trim Axial Load Factor] 

Stability and control derivatives will now be read from a file. 

To continue, press F2 

DISPLAY open loop dynamics data 

YB - [YB(9,5)1 YBb = [YBb(9,5)1 

LB' - [LB'(9,5)1 LB'b = [LB'b(9,5)1 

NB' = [N/3'(9,5)] Ng'b - [NB'b(9,5)1 

Lp' - [Lp'(9,5)] Lp'b - [Lp'b(9,5)] 

Np' - [Np'(9,5)] Np'b - [Np'b(9,5)] 

Lr' = [Lr'(9,5)] Lr'b - [Lr'b(9,5)] 

Nr' = [Nr'(9,5)] Nr'b = [Nr'b(9,5)] 

YSa* = [Y6a#(9,5)] YSa*b - [Y6a#b(9,5)] 

LSa' = [LSa'(9,5)] LGa'b = [LSa'b(9,5)] 

NSa' = [N6a'(9,5)] NSa'b - [NSa'b(9,5)] 

Y6r' = [Y6r#(9,5)] YGr'b = [YSr#b(9,5)] 

LSr' = [LSr'(9,5)] Llr'b = [LGr'b(9,5)] 

NSr' - [NSr'(9,5)] NCr'b = [NSr'b(9,5)] 

The open loop aircraft dynamics will now be computed. 

To continue, press F2 

DISPLAY Literal approximate factors 

TR-1228-1-11 87 
The literal approximate factors for the bare aircraft dynamics will now be 

obtained. 

To continue, press F2 

DISPLAY Aircraft Summary 

AIRCRAFT SUMMARY 

The flight condition and trim data and all necessary aircraft data have been 

obtained for the [Degrees of freedom for control] of: 

Aircraft [Aircraft designation] 

Type [Aircraft type] 

Mil-Spec Class [Aircraft classification] 

The design requirements will now be set for the current aircraft and flight 

condition. 

! 

END 

To continue, press F2 

I TR-1228-1-11 aa 
LITFACPRL 

. 

TR-1228-1-11 89 
! "LITFAC . PRL" 

! 

! SYSTEMS TECHNOLOGY, INC Hawthorne, CA 

TITLE Bare Airframe Literal Approximate Factors (LITFAC) DISPLAY 

This expert formulates literal approximate factors for poles 

and zeros of the bare airframe. 

To continue, press F3 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

................................................................ 

! 

! Parameter Initialization Statements 

! 

................................................................ 

! 

! Control Element Selectors 

THRESHOLD - 60 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV.SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The YWLTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI . SHR" and combined with this knowledge base 

! during compilation. 

$MULTI . SHR 

................................................................ 

1 

TR-1228-1-11 90 
! Goal Outline 

1. Literal poles have been enumerated 

1.1 Literal factors are defined 

! 

! 

! 

! Rules 

! 

................................................................. 

! 

RULE for initial literal parameters 

Wrs$abs := SQRT(ABS((g/uo)*(Nr‘*LB’/NB‘ - Lr’))) 

Wd$abs :- SQRT(ABS(NB‘)) 

ZWrs$abs := ABS(-Lp’+(v’/N@’)*(Np’-g/uo))/2 

ZWd$abs :- ABS(-(Yv+Nr’)-(L/3’/NB’)*(Np’-g/Uo))/2 

IF Bare airframe dynamics have been obtained 

THEN Initial literal parameters have been calculated 

AND Zrs$abs :- ZWrs$abs/Wrs$abs 

AND Zd$abs := ZWd$abs/Wd$abs 

RULE for literal roll spiral mode complexity 

IF Initial literal parameters have been calculated 

AND Zrs$abs < 1 

THEN Literal roll spiral mode‘complexity IS complex 

ELSE Literal roll spiral mode complexity IS real 

RULE for literal dutch roll mode complexity 

IF Initial literal parameters have been calculated 

AND Zd$abs < 1 

THEN Literal dutch roll mode complexity IS complex 

ELSE Literal dutch roll mode complexity IS real 

RULE for number of real poles 

IF Literal roll spiral mode complexity IS complex 

AND Literal dutch roll mode complexity IS complex 

THEN Literal poles have been enumerated 

AND Number of literal real poles :- 0 

AND Number of literal complex pole pairs := 2 

AND Literal roll spiral coupling exists 

RULE for number of real roots 

IF Literal roll spiral mode complexity IS real 

AND Literal dutch roll mode complexity IS complex 

THEN Literal poles have been enumerated 

AND Number of literal real poles :- 2 

AND Number of literal complex pole pairs := 1 

RULE for number of real roots 

IF Literal roll spiral mode complexity IS complex 

AND Literal dutch roll mode complexity IS real 

TR-1228-1-11 91 
THEN Literal poles have been enumerated 

AND Number of literal real poles :- 0 

AND Number of literal complex pole pairs :- 1 

AND Literal roll spiral coupling exists 

RULE for number of real roots 

IF Literal roll spiral mode complexity IS real 

AND Literal dutch roll mode complexity IS real 

THEN Literal poles have been enumerated 

AND Number of literal real poles :- 4 

AND Number of literal complex pole pairs :- 0 

RULE for standard literal factors 

IF Literal roll spiral mode complexity IS real 

AND Literal dutch roll mode complexity IS complex 

THEN Literal factors are defined for bare airframe poles 

AND ITr$ :- -Lp'+(L8'/NB')*(Np'-g/uo) 

AND ITS$ :- (g/Uo)*(Nr'*L/3'/NB' - Lr')/ITr$ 

AND Wd$ := SQRT(NB') 

AND ZWd$ := (-(Yv+Nr')-(LB'/N/?')"(Np'-g/Uo))/2 

AND Zd$ :- ZWd$/Wd$ 

AND DISPLAY Literal factor summary 1 

RULE for initiating bare airframe pole identification 

IF Literal factors are defined for bare airframe poles 

THEN Literal factors are defined 

AND CHAIN C:\FCSXPRT\BAROOTID.PRL 

! 

! Information Display Text 

1 

DISPLAY Literal factor summary 1 

RESULTS FROM LITERAL APPROXIMATE FACTORS 

Roll spiral mode is [Literal roll spiral mode complexity] 

Dutch roll mode is [Literal dutch roll mode complexity] 

Spiral mode inverse time constant = [ITs$(9,5)] radlsec 

Roll subsidence mode inverse time constant = [ITr$(7,3)] radlsec 

Dutch roll undamped natural frequency = [Wd$(6,2)] radlsec 

Dutch roll damping ratio = [zd$(8,4)1 

To continue, press F2 

! 

END 

TR-1228-1-11 I 92 
TR-1228-1-11 

BAROOTI D.PRL 

93 
! "BAROOTID . PRL" 

! 

! SYSTEMS TECHNOLOGY, INC Hawthorne, CA 

TITLE Bare Airframe Pole and Zero Identification (BAROOTID) DISPLAY 

This expert manages the physical identification of the poles and zeros 

of the bare airframe. 

To continue, press F3 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

NUMERIC Number of numerical real zeros 

AND Number of numerical complex zero pairs 

AND Number of numerical real poles 

AND Number of nonminimum phase numerical real zeros 

AND Number of unstable numerical real poles 

AND High frequency gain 

AND Inverse time constant of real zero #1 

AND Inverse time constant of real zero #2 

AND Inverse time constant of real zero #3 

AND Inverse time constant of real zero #4 

AND Inverse time constant of real zero #5 

AND Damping ratio of complex zero pair #1 

AND Natural frequency of complex zero pair #1 

AND Damping ratio of complex zero pair #2 

AND natural frequency of complex zero pair #2 

AND Damping ratio of complex zero pair #3 

AND natural frequency of complex zero pair #3 

AND Damping ratio of complex zero pair #4 

AND natural frequency of complex zero pair #4 

AND Damping ratio of complex zero pair #5 

AND natural frequency of complex zero pair #5 

AND Damping ratio of complex zero pair #6 

I 

I 

AND Number of numerical complex pole pairs 

AND Number of nonminimum phase numerical complex zero pairs 

AND Number of unstable numerical complex pole pairs 

I 

I 

I 

I AND Inverse time constant of real zero #6 

TR-1228-1-11 94 
AND natural frequency of complex zero pair #6 

AND Inverse time constant of real pole #1 

AND Inverse time constant of real pole #2 

AND Inverse time constant of real pole #3 

AND Inverse time constant of real pole #4 

AND Inverse time constant of real pole #6 

AND Damping ratio of complex pole pair #1 

AND natural frequency of complex pole pair #1 

AND Damping ratio of complex pole pair #2 

AND natural frequency of complex pole pair #2 

AND Damping ratio of complex pole pair #3 

AND natural frequency of complex pole pair #3 

AND Damping ratio of complex pole pair #4 

AND natural frequency of complex pole pair #4 

AND Damping ratio of complex pole pair #5 

AND natural frequency of complex pole pair #5 

AND Damping ratio of complex pole pair #6 

AND natural frequency of complex pole pair #6 

AND Inverse time constant of bare airframe real pole #1 

AND Inverse time constant of bare airframe real pole #2 

AND Damping ratio of bare airframe complex pole pair #1 

AND Natural frequency of bare airframe complex pole pair #1 

5 AND Inverse time constant of real pole #5 

STRING St7 

AND St8 

AND St15 

AND St35 

AND St36 

AND St37 

................................................................ 

! 

! Parameter Initialization Statements 

! 

! 

! 

! 

INIT St7 := "C:\STI" 

! 

AND St8 :- "CC.EXE" 

! 

AND St15 := "@BAPDA.MAC,HIOO,GIOO1ll' 

! 

! String variables sent to program "TFCCL5" 

! 

AND St35 :- "C:\STI\$$" 

! Name of pbl6a file in Program CC format 

AND St36 :- "G10011" 

! 

AND St37 :=- "C:\FCSDAT\BAPDA.PRM" 

String variables sent to PROCAU program to activate an external program 

Subdirectory containing the external program 

Name of the external program 

Macro parameters passed to Program CC 

Name of pbl6a file in LEVEL 5 format output by TFCCL5 

TR-1228-1-11 95 
! 

REINIT St7 :- "C:\STI" 

! 

AND St8 :- "CC.EXE" 

! 

AND St15 :- "@BAPDA.MAC,H100,G1001ln 

! 

! String variables sent to program "TFCCL5" 

! 

AND St35 :- "C:\STI\$$" 

! Name of pbl6a file in Program CC format 

AND St36 :- "G10011" 

! Name of pbl6a file in LEVEL 5 format output by TFCCL5 

AND St37 :- "C:\FCSDAT\BAPDA.PRM" 

Subdirectory containing the external program 

Name of the external program 

Macro parameters passed to Program CC 

................................................................ 

! 

! Control Element Selectors 

THRESHOLD - 60 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV. SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI . SHR" and combined with this knowledge base 

! during compilation. 

~ 

$MULTI . SHR 

................................................................ 

! 

! Goal Outline 

1. Generic bare airframe poles are defined 

1.1 Bare airframe poles are identified 

! 

1 Rules 

! 

................................................................. 

RULE for extracting pbl6a 

! Executes macro "BAPDA" in Program CC which extracts the pbl6a transfer 

I function from the bare airframe transfer function matrix (element (1,l) 

! in H100) and stores it in file n$$glOO1lll. 

TR-1228-1-11 96 

a 
IF Literal factors are defined 

AND ACTIVATE C:\STI\PROCALL.EXE 

SEND St7 ! St7 :- "C:\STI", Subdirectory containing external program (CC) 

SEND St8 ! St8 :- "CC.EXE", Name of the external program 

SEND St15 ! St15 := "@BAPDA.MAC", Macro parameters passed to Program CC 

THEN Bare airframe pbl6a has been generated 

RULE for reading bare airframe pbl6a 

! Activates program "TFCCL5" to convert bare airframe pbl6a (in Program CC 

! file $$g10011) to LEVEL 5 format stored in file BAPDA.PRM. This file is 

! then read into the knowledge base. 

IF Bare airframe pbl6a has been generated 

AND ACTIVATE C:\STI\TFCCLS.EXE 

SEND St35 

SEND St36 ! St36 :- "G10011", pbl6a file in Program CC format 

SEND St37 ! St37 :- "C:\FCSDAT\BAPDA.PRM", pb(6a file in LEVEL 5 format 

THEN Bare airframe identification transfer function has been read 

! File BAPDA.PRM contains a transfer function in a format readable by LEVEL 5 

! Zeros and poles are listed in order of increasing frequency 

AND READ C:\FCSDAT\BAPDA.PRM 

DATA Number of numerical real zeros 

DATA Number of numerical complex zero pairs 

DATA Number of numerical real poles 

DATA Number of numerical complex pole pairs 

DATA Number of nonminimum phase numerical real zeros 

DATA Number of nonminimum phase numerical complex zero pairs 

DATA Number of unstable numerical real poles 

DATA Number of unstable numerical complex pole pairs 

DATA High frequency gain 

DATA Inverse time constant of real zero #1 

DATA Inverse time constant of real zero #2 

DATA Inverse time constant of real zero #3 

DATA Inverse time constant of real zero #4 

DATA Inverse time constant of real zero #5 

DATA Inverse time constant of real zero #6 

DATA Damping ratio of complex zero pair #1 

DATA natural frequency of complex zero pair #1 

DATA Damping ratio of complex zero pair #2 

DATA natural frequency of complex zero pair #2 

DATA Damping ratio of complex zero pair #3 

DATA natural frequency of complex zero pair #3 

DATA Damping ratio of complex zero pair #4 

DATA natural frequency of complex zero pair #4 

DATA Damping ratio of complex zero pair #5 

DATA natural frequency of complex zero pair #5 

DATA Damping ratio of complex zero pair #6 

DATA natural frequency of complex zero pair #6 

DATA Inverse time constant of real pole #1 

DATA Inverse time constant of real pole #2 

DATA Inverse time constant of real pole #3 

DATA Inverse time constant of real pole #4 

DATA Inverse time constant of real pole t5 

TR-1228-1-11 97 
DATA Inverse time constant of real pole #6 

DATA Damping ratio of complex pole pair #l 

DATA natural frequency of complex pole pair #1 

DATA Damping ratio of complex pole pair #2 

DATA natural frequency of complex pole pair #2 

DATA Damping ratio of complex pole pair #3 

DATA natural frequency of complex pole pair #3 

DATA Damping ratio of complex pole pair #4 

DATA natural frequency of complex pole pair #4 

DATA Damping ratio of complex pole pair #5 

DATA natural frequency of complex pole pair #5 

DATA Damping ratio of complex pole pair #6 

DATA natural frequency of complex pole pair #6 

AND DISPLAY TF data 

n 

RULE for standard generic bare airframe poles 

IF Bare airframe identification transfer function has been read 

AND Number of numerical real poles = 2 

THEN Generic bare airframe poles are defined 

AND Number of bare airframe numerical real poles :- Number of numerical real poles 

AND Number of bare airframe numerical complex pole pairs := Number of numerical complex 

pole pairs 

AND Inverse time constant of bare airframe real pole #1 :- Inverse time constant of real 

pole #1 

AND Inverse time constant of bare airframe real pole #2 := Inverse time constant of real 

pole #2 

AND Damping ratio of bare airframe complex pole pair #1 := Damping ratio of complex pole 

pair #1 

AND natural frequency of bare airframe complex pole pair #1 :- natural.frequency of 

complex pole pair #1 

RULE for physically possible bare airframe real poles 

IF Number of bare airframe numerical real poles - 0 

OR Number of bare airframe numerical real poles - 2 

OR Number of bare airframe numerical real poles - 4 

THEN Bare airframe real poles are feasible 

ELSE NOT Bare airframe real poles are feasible 

RULE for physically possible bare airframe complex poles 

IF Number of bare airframe numerical complex pole pairs = 0 

OR Number of bare airframe numerical complex pole pairs = 1 

OR Number of bare airframe numerical complex pole pairs = 2 

THEN Bare airframe complex poles are feasible 

~ ELSE NOT Bare airframe complex poles are feasible 

RULE for physically possible bare airframe poles 

IF Bare airframe real poles are feasible 

AND Bare airframe complex poles are feasible 

THEN Bare airframe poles are feasible 

ELSE NOT Bare airframe poles are feasible 

I AND DISPLAY Impossible poles 

TR-1228-1-11 98 
RULE for literal approximate pole factor validity check #2 

IF Bare airframe poles are feasible 

AND Number of literal real poles - Number of numerical real poles 

THEN Literal poles are valid at check #2 

RULE for standard poles 

IF Literal poles are valid at check #2 

AND Literal roll spiral mode complexity IS real 

AND Literal dutch roll mode complexity IS complex 

THEN Bare airframe poles are tentatively identified 

AND ITS :- Inverse time constant of bare airframe real pole #1 

AND ITr :- Inverse time constant of bare airframe real pole #2 

AND Zd :- Damping ratio of bare airframe complex pole pair #1 

AND Wd :- natural frequency of bare airframe complex pole pair #1 

. 

RULE for literal approximate pole factor validity check #3 

IF Bare airframe poles are tentatively identified 

AND Literal roll spiral mode complexity IS real 

AND Literal dutch roll mode complexity IS complex 

AND ABS(1-ABS(ITr/ITr$)) < 0.2 

AND ABS(l-ABS(ITs/ITS$)) < 0.2 

AND ABS(1-ABS(Zd/Zd$)) < 0.25 

AND ABS(1-ABS(Wd/Wd$)) < 0.2 

THEN Literal poles are valid at check #3 

AND DISPLAY Pole summary 1 

RULE for returning to calling expert 

IF Literal poles are valid at check #3 

THEN Bare airframe poles are identifie'd 

AND Literal approximate factors have been obtained 

AND CHAIN C:\FCSXPRT\FLTCOND 

ELSE NOT Literal approximate factors have been obtained 

! 

! Information Display Text 

I 

DISPLAY Impossible poles 

The bare airframe dynamics calculations have resulted in [Number of bare airframe 

numerical real poles] 

real poles and [Number of bare airframe numerical complex pole pairs] complex pole pairs 

which is physically impossible. 

To continue, press F2 

DISPLAY Pole summary 1 

IDENTIFIED BARE AIRFRAME POLES FROM NUMERICAL FACTORING 

TR-1228-1-11 99 
Roll spiral mode is [Literal roll spiral mode complexity] 

Dutch roll mode is [Literal dutch roll mode complexity] 

Spiral mode inverse time constant - [ITs(9,5)] radlsec 

Roll subsidence mode inverse time constant - [ITr(7,3)] radlsec 

Dutch roll undamped natural frequency - [Wd(6,2)] radlsec 

Dutch roll damping ratio - [Zd(8,4)1 

To continue, press F2 

DISPLAY TF data 

Number of real zeros - [Number of numerical real zeros] 

Number of complex zero pairs - [Number of numerical complex zero pairs] 

Number of real poles - [Number of numerical real poles] 

Number of complex poles - [Number of numerical complex pole pairs] 

Number of nonminimum phase real zeros - [Number of nonminimum phase numerical real 

zeros] 

Number of nonminimum phase complex zero - [Number of nonminimum phase numerical complex 

zero pairs] 

Number of unstble real poles - [Number of unstable numerical real poles] 

Number of unstable complex poles - [Number of unstable numerical complex pole pairs] 

High frequency gain - [High frequency gain] 

Zeros : 

Real - [Inverse time constant of real zero #1] 

Real - [Inverse time constant of real zero #2] 

Real - [Inverse time constant of real zero #3] 

Real - [Inverse time constant of real zero #4] 

Real - [Inverse time constant of real zero #5] 

Real - [Inverse time constant of real zero #6] 

Damping ratio - [Damping ratio of complex zero pair #1] 

Frequency - [natural frequency of complex zero pair #1] 

Damping ratio - [Damping ratio of complex zero pair #2] 

Frequency - [natural frequency of complex zero pair #2] 

Damping ratio - [Damping ratio of complex zero pair #3] 

Frequency - [natural frequency of complex zero pair #3] 

Damping ratio - [Damping ratio of complex zero pair #4] 

Frequency - [natural frequency of complex zero pair #4] 

Damping ratio - [Damping ratio of complex zero pair #5] 

Damping ratio - [Damping ratio of complex zero pair #6] 

I 

I Frequency - [natural frequency of complex zero pair #5] 

I Frequency - [natural frequency of complex zero pair #6] 

I Poles : 

I Real - [Inverse time constant of real pole #1] 

Real - [Inverse time constant of real pole #2] 

Real - [Inverse time constant of real pole #3] 

Real - [Inverse time constant of real pole #4] I 

I TR-1228-1-11 100 
Real - [Inverse time constant of real pole #5] 

Real - [Inverse time constant of real pole #6] 

Damping ratio - [Damping ratio of complex pole pair #1] 

Frequency - [natural frequency of complex pole pair #1] 

Damping ratio - [Damping ratio of complex pole pair #2] 

Frequnecy - [natural frequency of complex pole pair #2] 

Damping ratio - [Damping ratio of complex pole pair #3] 

Frequency - [natural frequency of complex pole pair #3] 

Damping ratio - [Damping ratio of complex pole pair #4] 

Frequency - [natural frequency of complex pole pair #4] 

Damping ratio - [Damping ratio of complex pole pair #5] 

Frequency - [natural frequency of complex pole pair #5] 

Damping ratio - [Damping ratio of complex pole pair #6] 

Frequency - [natural frequency of complex pole pair #6] 

! 

END 

TR-1228-1-11 101 
TR-1228-1-11 

SPECSET.PRL 

192 
! " SPECSET. PRL" 

! 

TITLE AIRCRAFT DYNAMICS REQUIREMENTS SETUP {SPECSET) DISPLAY 

This expert assists in setting up design requirements appropriate to the 

aircraft and flight condition. 

To continue, PRESS F3 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

................................................................ 

! 

! Parameter Initialization Statements 

! 

................................................................ 

! 

! Control Element Selectors 

! 

THRESHOLD - 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV. SHR 

! 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The llMULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI . SHR" and combined with this knowledge base 

! during compilation. 

! 

$MULTI . SHR 

................................................................ 

! 

1 

1 

TR-1228-1-11 103 
! 

! Goal Outline 

! 

! 

1. requirements are set for the current case 

! 

! 

! Rules 

I 

RULE for.setting dutch roll damping ratio spec 

IF Aircraft classification IS Class IV 

AND Flight phase category IS Category CO 

THEN Dutch roll damping ratio spec is set 

AND Dutch roll damping ratio spec :- 0.35 

RULE for dutch roll mode specs 

IF Dutch roll damping ratio spec is set 

! AND Dutch roll natural frequency spec is set 

THEN Dutch roll mode specs are set 

RULE for setting roll subsidence mode time constant 

IF Aircraft classification IS Class IV 

AND Flight phase category IS Category CO 

THEN Roll subsidence mode time constant spec is set 

AND Roll subsidence mode time constant spec :- 1.0 

RULE for roll subsidence mode specs 

IF Roll subsidence mode time constant spec is set 

THEN Roll subsidence mode specs are set 

RULE for lateral directional specs 

IF Roll subsidence mode specs are set 

AND Dutch roll mode specs are set 

THEN Lateral directional specs are set 

RULE for determining if specs are set 

IF Lateral directional specs are set 

THEN Requirements are set for the current case 

AND DISPLAY spec setup 

AND FORGET open loop aircraft model is setup 

AND FORGET open loop aircraft dynamics have been obtained 

AND FORGET open loop aircraft poles and zeros have been identified 

AND FORGET open loop aircraft spec comparison is complete 

AND FORGET open loop aircraft dynamics are adequate 

AND FORGET open loop aircraft assessment is complete 

AND CHAIN C:\FCSXPRT\ASSESSOL 

! 

! 

! Information Display Text 

TR-1228-1-11 104 
DISPLAY spec setup 

The general requirements and specifications have been specialized to the 

current aircraft and flight conditions. 

The open loop aircraft specifications must now be assessed with respect to 

these requirements. 

To continue, press F2 

! 

END 

TR-1228-1-11 105 
TR-1228-1-11 

ASSESSOL.PRL 

106 
! "ASSESSOL. PRL" 

! 

TITLE Open Loop Aircraft Assessment (ASSESSOL) DISPLAY 

This expert assists in the assessment of the open loop aircraft dynamics. 

. To continue, PRESS F3 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

1 "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

................................................................ 

! 

! Parameter Initiaiization Statements 

! 

INIT St7 :- "C:\STI" ! Subdirectory where PROGRAM CC resides 

AND St8 :- "CC.EXE" ! PROGRAM CC calling syntax 

AND St16 :- "@OLAIRPTS.MAC" ! Parameter to be passed to PROGRAM CC 

REINIT St7 :- "C:\STI" ! Subdirectory where PROGRAM CC resides 

AND St8 :- "CC.EXE" ! PROGRAM CC calling syntax 

AND St16 :- "@OLAIRPLN.MAC" ! Parameter to be passed to PROGRAM CC 

................................................................. 

! 

! Control Element Selectors 

I 

THRESHOLD * 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$ExHAUSTv. SHR 

..................................................................... 

! 

! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI. SHR" and combined with this knowledge base 

! during compilation. 

! Multiattributed Objects Declarations 

TR-1228-1-11 107 
! 

$MULTI . SHR 

! 

................................................................ 

! 

! Goal Outline 

! 

1. open loop aircraft assessment is complete 

! 

................................................................ 

! 

! Rules 

! 

RULE for generating open loop aircraft dynamics 

IF Complete aircraft data has been obtained 

! 

! 

! Calling external program 

! 

! 

AND ACTIVATE C:\STI\PROCALL.EXE 

SEND St7 ! Subdirectory where the program resides 

SEND St8 ! Program that will be called by Level 5 

SEND St16 ! Parameter to be passed to program 

! 

! 

! 

THEN open loop aircraft dynamics have been obtained 

AND DISPLAY dynamic characteristics 

RULE for assessing the open loop dynamics 

IF open loop aircraft dynamics have been obtained 

AND FORGET bare airframe dutch roll damping ratio has been assessed 

AND FORGET bare airframe dutch roll mode dynamics are adequate 

AND FORGET bare airframe dutch roll mode has been assessed 

AND FORGET bare airframe roll mode time constant has been assessed 

AND FORGET bare airframe roll subsidence mode dynamics are adequate 

AND FORGET bare airframe roll subsidence mode has been assessed 

AND FORGET bare airframe spiral mode dynamics are adequate 

AND FORGET open loop aircraft dynamics are adequate 

AND FORGET system has been compared with the specifications 

AND FORGET open loop aircraft spec comparison is complete 

AND FORGET bare airframe dutch roll damping ratio assessment 

AND FORGET bare airframe dutch roll natural frequency 

AND FORGET bare airframe roll subsidence mode time constant assessment 

AND CHAIN C:\FCSXPRT\SPECHKOL 

THEN open loop aircraft spec comparison is complete 

AND DISPLAY dynamics assessment 

RULE for treating an inadequate airframe 

IF open loop aircraft spec comparison is complete 

AND NOT open loop aircraft dynamics are adequate 

TR-1228-1-11 108 

. 
THEN open loop aircraft assessment is complete 

AND DISPLAY Airframe Summary ' 

AND FORGET yaw damper is a candidate loop 

AND FORGET roll damper is a candidate loop 

AND FORGET sideslip to rudder is a candidate loop 

AND FORGET lateral acceleration to rudder is a candidate loop 

AND FORGET pitch rate to elevator is a candidate loop 

AND FORGET candidate loops have been identified 

AND FORGET candidate architectures have been identified 

AND FORGET RD&YD is a candidate architecture 

AND FORGET RD&B-DR is a candidate architecture 

AND FORGET RD&AY-DR is a candidate architecture 

AND FORGET Candidate architectures have been ranked 

AND FORGET Prospectus for control has been defined 

AND CHAIN C:\FCSXPRT\PRSPCTUS 

U AND FORGET Candidate loops have been reported 

RULE for announcing an adequate airframe 

IF open loop aircraft spec comparison is complete 

AND open loop aircraft dynamics are adequate 

THEN open loop aircraft assessment is complete 

AND DISPLAY Airframe Summary 

AND CHAIN C:\FCSXPRT\GENERATE 

! 

! 

! Information Display Text 

! 

DISPLAY dynamic characteristics 

The dynamics characteristics have been obtained for the system 

To continue, Press F2 

! DISPLAY poles and zeros 

! The poles and zeros have been identified as follows: 

! 

DISPLAY dynamics assessment 

To continue, Press F2 

The assessment of the system dynamics indicates the following problems: 

To continue, Press F2 

! DISPLAY dynamics diagnosis 

! The diagnosis of the systems problems indicates that: 

TR-1228-1-11 109 
! 

DISPLAY Airframe Summary 

To continue, Press F2 

The open loop aircraft has been assessed and: 

the dynamics are adequate - [open loop aircraft dynamics are adequate] 

To continue, press F2 

END 

~ 

~ 

TR-1228-1-11 110 
TR-1228-1-11 

SPECHKOL.PRL 

11 1 
! "SPECHKOL. PRL" 

! 

TITLE BARE AIRCRAFT DYNAMICS SPECIFICATION CHECKER (SPECHKOL) DISPLAY 

This expert assists in comparing the open loop aircraft to the appropriate 

design requirements. 

To continue, PRESS F3 

............................................................... 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! 

! Data Type Declarations 

! 

I 

................................................................ 

! 

! Parameter Initialization Statements 

! 

................................................................ 

! 

! Control Element Selectors 

THRESHOLD - 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$ExHAUSTv. SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI . SHR" and combined with this knowledge base 

! during compilation. 

! 

$MULTI . SHR 

! 

! 

! 

................................................................ I 

TR-1228-1-11 112 
! Goal Outline 

! 

! 

1. open loop aircraft spec comparison is complete 

! 

! 

! 

! Rules 

! 

RULE for assessing bare airframe dutch roll damping ratio 

IF Zd >- dutch roll damping ratio spec 

THEN bare airframe dutch roll damping ratio assessment IS adequate 

AND bare airframe dutch roll damping ratio has been assessed 

ELSE bare airframe dutch roll damping ratio assessment IS too low 

AND bare airframe dutch roll damping ratio has been assessed 

- 

RULE for assessing bare airframe dutch roll mode 

IF bare airframe dutch roll damping ratio assessment IS adequate 

! AND bare airframe dutch roll natural frequency IS adequate 

THEN bare airframe dutch roll mode dynamics are adequate 

AND bare aZrframe dutch roll mode has been assessed 

ELSE NOT bare airframe dutch roll mode dynamics are adequate 

AND bare airframe dutch roll mode has been assessed 

RULE for assessing bare airframe roll subsidence mode 

IF ITr >- l/(Roll subsidence mode time constant spec) 

THEN bare airframe roll mode time constant assessment IS adequate 

AND bare airframe roll mode time constant has been assessed 

ELSE bare airframe roll mode time constant assessment IS too high 

AND bare airframe roll mode time constant has been assessed 

RULE for assessing bare airframe roll subsidence mode 

IF bare airframe roll mode time constant assessment IS adequate 

THEN bare airframe roll subsidence mode dynamics are adequate 

AND bare airframe roll subsidence mode has been assessed 

ELSE NOT bare airframe roll subsidence mode dynamics are adequate 

AND bare airframe roll subsidence mode has been assessed 

RULE for assessing bare airframe modal characteristics 

IF bare airframe dutch roll mode dynamics are adequate 

AND bare airframe roll subsidence mode dynamics are adequate 

! AND bare airframe spiral mode dynamics are adequate 

THEN open loop aircraft dynamics are adequate 

AND system has been compared with the specifications 

RULE for assessing bare airframe modal characteristics 

IF bare airframe dutch roll mode dynamics are adequate 

AND NOT bare airframe roll subsidence mode dynamics are adequate 

! AND bare airframe spiral mode dynamics are adequate 

THEN NOT open loop aircraft dynamics are adequate 

AND system has been compared with the specifications 

TR-1228-1-11 113 
RULE for assessing bare airframe modal characteristics 

IF NOT bare airframe dutch roll mode dynamics are adequate 

AND bare airframe roll subsidence mode dynamics are adequate 

! AND bare airframe spiral mode dynamics are adequate 

THEN NOT open loop aircraft dynamics are adequate 

AND system has been compared with the specifications 

RULE for assessing bare airframe modal characteristics 

IF NOT bare airframe dutch roll mode dynamics are adequate 

AND NOT bare airframe roll subsidence mode dynamics are adequate 

! AND bare airframe spiral mode dynamics are adequate 

THEN NOT open loop aircraft dynamics are adequate 

AND system has been compared with the specifications 

RULE for determining if spec comparison has been completed 

IF system has been compared with the specifications 

THEN open loop aircraft spec comparison is complete 

AND DISPLAY spec comparison results 

AND CHAIN C:\FCSXPRT\ASSESSOL 

! 

! 

!. 

! Information Display Text 

DISPLAY spec comparison results 

1 

Comparison of the system with the requirements indicates that-bare airframe 

Dutch roll damping ratio is: 

Roll subsidence mode is: [bare airframe roll mode time constant assessment] 

[bare airframe dutch roll damping ratio assessment] 

Therefore, it is [open loop aircraft dynamics are adequate] that the 

bare airframe modal dynamics are adequate. 

To continue, press F2 

END 

, 

I 

TR-1228-1-11 114 
TR-1228-1-11 

PRSPCTUS.PRL 

115 
! "PRSPCTUS . PRL" 

! 

TITLE FCS Prospectus Expert { PRSPCTUS 1 DISPLAY 

This Expert assists in definition of candidate loops that are likely to be 

useful in the FCS design and combines these loops into recommended 

architectures ranked by their potential for the current case. 

I To continue, press F3 

I 

............................................................... 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations. 

................................................................ 

! 

! Parameter Initialization Statements 

................................................................ 

! 

! Control Element Selectors 

I 

"SHAREFCT. SHR" and combined with this knowledge base during compilation. 

.! 

THRESHOLD - 100 

CONFIDENCE OFF 

UNKNOWN CONTINUE 

~ 

i 

I GOALSELECT ON 

$EXHAUSTv. SHR 

I 

I 1 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI. SHR" and combined with this knowledge base 

! during compilation. 

i 

1 

$MULTI . SHR 

.............................................................. 

! 

! Goal Outline 

I ~ 

TR-1228-1-11 116 
1. Candidate loops have been reported 

1.1 Candidate architectures have been identified 

~ 

1.1.1 Prospectus for control has been defined 

! 

- ! 

! Rules 

! 

.............................................................. 

! 

! Rules for identifying candidate loops based on bare airframe deficiencies 

RULE for roll damper loop candidacy 

IF bare airframe roll mode time constant assessment IS too high 

OR yaw damper is a candidate loop 

THEN candidate loops have been identified 

AND roll damper is a candidate loop 

RULE for yaw damper loop candidacy 

IF bare airframe dutch roll damping ratio assessment IS too low 

THEN candidate loops have been identified 

AND yaw damper is a candidate loop 

AND sideslip to rudder is a candidate loop 

AND lateral acceleration to rudder is a candidate loop 

RULE for reporting candidate loops 

IF candidate loops have been identifieci 

THEN Candidate loops have been. reported 

AND DISPLAY Candidate loops 

.......................................................... 

! 

! Rules for identifying candidate architectures 

RULE for RD&YD architecture candidacy 

IF Degrees of freedom for control ARE lateral directional axes 

AND roll damper is a candidate loop 

AND yaw damper is a candidate loop 

THEN candidate architectures have been identified 

AND RD&YD is a candidate architecture 

RULE for RD6rB DR architecture candidacy 

IF Degrees of-freedom for control ARE lateral directional axes 

AND roll damper is a candidate loop 

AND sideslip to rudder is a candidate loop 

THEN candidate architectures have been identified 

AND RD&B-DR is a candidate architecture 

RULE for RDUY DR architecture candidacy 

IF Degrees of freedom for control ARE lateral directional axes 

AND roll damper is a candidate loop 

TR-1228-1-11 117 
AND lateral acceleration to rudder is a candidate loop 

THEN candidate architectures have been identified 

AND RDUY - DR is a candidate architecture 

I Loop Potentially useful ? 

........................................................... 

! 

! 

! they should be considered. 

Rules for ranking candidate architectures by the order in which 

I Roll damper [roll damper is a candidate loop] 

Yaw damper 

Sideslip to rudder [sideslip to rudder is a candidate loop] 

Ay to rudder 

[yaw damper is a candidate loop] 

[lateral acceleration to rudder is a candidate loop] 

RULE for RD&YD architecture consideration ranking 

IF Degrees of freedom for control ARE lateral directional axes 

AND RD&> is a candidate architecture 

AND RD&B DR is a candidate architecture 

AND RDUY-DR is a candidate architecture 

THEN Candidate architectures have been ranked 

AND First architecture for consideration IS RD&YD 

AND Second architecture for consideration IS RD&B-DR 

AND Third architecture for consideration IS RDUY-DR 

RULE for reporting candidate architecture rankings 

IF Candidate architectures have been ranked 

THEN Prospectus for control has been defined 

AND CHAIN C:\FCSXPRT\GENERATE 

AND DISPLAY Candidate architectures 

! 

! 

! Information Displiy Text 

DISPLAY Candidate Loops 

CANDIDATE FCS LOOPS 

The candidate loops potentially useful for the control of the 

[Degrees of freedom for control] of this (aircraft type) have been 

I identified and include: 

To continue, press F2 

DISPLAY Candidate Architectures 

I TR-1228-1-11 118 
CANDIDATE FCS ARCHITECTURES 

The candidate FCS architectures potentially useful for the control of the 

[Degrees of freedom for control] of this (aircraft type) have been 

identified and include: 

. To be examined: 

1st [First architecture for consideration] 

2nd [Second architecture for consideration] 

3rd [Third architecture for consideration] 

You may now begin FCS design. 

To continue, press F2 

TEXT RD&YD 

Roll damper plus yaw damper 

TEXT RD&B-DR 

Roll damper plus sideslip to rudder 

TEXT RD&AY-DR 

Roll damper plus lateral acceleration to rudder 

! 

END 

TR-1228-1-11 119 
! "ARCH. PRL" 

! 

TITLE FCS ARCHITECTURE SELECTION EXPERT ( ARCH 1 DISPLAY 

This expert assists in the selection of one of the candidate architectures to 

to be pursued for the current aircraft. This architecture is referred to as 

the "current architecture". - 

To continue, PRESS F3 

! 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! 

! 

$SHAREFCT.SHR 

! 

............................................................... 

"SHAREFCT. SHR" and combined with this knowledge base during compilation 

................................................................ 

1 

! Data Type Declarations 

! 

................................................................. 

! 

! Parameter Initialization Statements 

! 

................................................................ 

! 

! Control Element Selectors 

THRESHOLD - 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV. SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! 

! 

! during compilation. 

The llMULTI" Declaration of multiattributed objects is stored in the 

"include" file named "MULTI. SHR" and combined with this knowledge base 

$MULTI . SHR 

................................................................ 

! 

! 

TR-1228-1-11 121 
! Goal Outline 

1. Current architecture has been selected 

1.1. Selection of current architecture has been completed 

I 

! 

! Rules 

! 

.............................................................. 

! 

! Rules for selecting the current architecture 

! The current architecture is the one currently being designed and evaluated 

I 

RULE for making RD&YD current architecture 

IF Degrees of freedom for control ARE lateral directional axes 

AND First architecture for consideration IS RD&YD 

AND RD&YD assessment IS assessed and adequate 

THEN Current architecture has been selected 

AND Current architecture IS RDlEB-DR 

ELSE Current architecture has been selected 

AND Current architecture IS RD&YD 

RULE for making RD&YD current architecture 

IF Degrees of freedom for control ARE lateral directional axes 

AND First architecture for consideration IS RD&YD 

AND RD&YD assessment IS assessed and inadequate 

THEN Current architecture has been selected 

AND Current architecture IS RD&YD 

.............................................................. 

! 

! 

! current architecture 

Rules for setting the sequence of loop closures during design of the 

RULE for setting of loop closure order 

IF Current architecture IS RD&yD 

THEN First loop to design has been specified 

AND First loop to design IS yaw damper 

................................................................. 

! 

! Rule for ending consultation 

RULE for exiting ARCH expert 

IF First loop to design has been specified 

THEN Selection of current architecture has been completed 

AND DISPLAY Architecture summary 

AND FORGET Current loop has been specified 

AND FORGET Current loop connections are set for design 

AND FORGET Current system design model is setup 

TR-1228-1-11 122 
AND FORGET Current loop must be designed 

AND FORGET Current architecture has been designed 

AND CHAIN C:\FCSXPRT\DESIGN 

! 

! 

! Information Display Text - 

DISPLAY Architecture summary 

The current FCS architecture selected for consideration is: 

[Current architecture] 

The first loop recommended for design within this architecture is: 

[First loop to design] 

To continue, press F2 

TEXT RD&YD 

Roll damper plus yaw damper 

TEXT RD&B-DR 

Roll damper plus sideslip to rudder 

TEXT RDUY-DR 

Roll damper plus lateral acceleration to rudder 

TEXT B-DR 

Sideslip to rudder 

TEXT AY-DR 

Lateral acceleration to rudder 

! 

END 

TR-1228-1-11 123 
TR-1228-1 -IJ 

DESIGN.PRL 

124 
! "DESIGN. PRL" 

, ! 

I TITLE FCS MOP DESIGN EXPERT (DESIGN) DISPLAY 

This expert assists in the design of individual loops. 

To continue, PRESS F3 

! 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

! ................................................................. 

! Parameter Initialization Statements 

I 

INIT yaw damper loop has been designed CF 0 

AND roll damper loop has been designed CF 0 

AND Sideslip to rudder loop has been designed CF 0 

AND Lateral acceleration to rudder loop has been designed CF 0 

- 

REINIT yaw damper loop has been designed CF 0 

AND roll damper loop has been designed CF 0 

AND Sideslip to rudder loop has been designed CF 0 

AND Lateral acceleration to rudder loop has been designed CF 0 

................................................................ 

! 

! Control Element Selectors 

THRESHOLD = 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV. SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

TR-1228-1-11 125 
! The WULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI . SHR" and combined with this knowledge base 

! during compilation. 

$MULTI . SHR 

................................................................ 

! 

! Goal Outline 

1 

1. Current loop has been specified 

1.1.1. 

1.1. Current loop connections are set for design 

Current loop must be designed 

1.1.1.1. Current architecture has been designed 

! 

! 

!. 

! Rules 

! 

.............................................................. 

! 

! Rules for selecting the current loop 

! 

! The current loop is the one currently being designed and evaluated 

! selection depends on what loops have previously been designed. 

RULE for making yaw damper the current loop 

IF First loop to design IS yaw damper 

AND NOT Yaw damper loop has been designed 

THEN Current loop has been specified 

AND Current loop IS yaw damper 

RULE for making yaw damper the current loop 

IF First loop to design IS yaw damper 

AND Yaw damper loop assessment IS assessed and inadequate 

THEN Current loop has been specified 

AND Current loop IS yaw damper 

RULE for making roll damper the current loop 

IF Current architecture IS RD&YD 

AND Yaw damper loop assessment IS assessed and adequate 

THEN Current loop has been specified 

AND Current loop IS roll damper 

RULE for making roll damper the current loop 

IF Current architecture IS RD&YD 

AND Yaw damper loop assessment IS assessed and adequate 

AND Roll damper loop assessment IS assessed and inadequate 

THEN Current loop has been specified 

AND Current loop IS roll damper 

Its 

TR-1228-1-11 126 
RULE for adequate RD&YD design 

IF Current architecture IS RD&YD 

AND Yaw damper loop assessment IS assessed and adequate 

AND Roll damper loop assessment IS assessed and adequate 

THEN Current loop has been specified 

AND Current loop connections are set for design 

AND Current loop must be designed 

.............................................................. 

! 

! Rules for setting loop connections 

RULE for setting up RD&YD system design model 

IF Current architecture IS RD&YD 

AND Current loop IS yaw damper 

AND NOT Yaw damper loop has been designed 

THEN Current loop connections are set for design 

AND Yaw damper loop connection IS open 

AND Roll damper loop connection IS open 

AND Sideslip to rudder loop connection IS open 

AND Lateral acceleration to rudder loop connection IS open 

RULE for setting up RD&YD system design model 

IF Current architecture IS RD&YD 

AND Current loop IS yaw damper 

AND Yaw damper loop assessment IS assessed and inadequate 

THEN Current loop connections are set for design 

AND Yaw damper loop connection IS open 

AND Roll damper loop’connection IS open 

AND Sideslip to rudder loop connection IS open 

AND Lateral acceleration to rudder loop connection IS open 

RULE for setting up RD&YD system design model 

IF Current architecture IS RD&YD 

AND Current loop IS roll damper 

AND Yaw damper loop assessment IS assessed and adequate 

THEN Current loop connections are set for design 

AND Yaw damper loop connection IS closed 

AND Roll damper loop connection IS open 

AND Sideslip to rudder loop connection IS open 

AND Lateral acceleration to rudder loop connection IS open 

.............................................................. 

! 

! Rules for initiating loop design 

RULE for initiating yaw damper design 

IF Current loop IS yaw damper 

THEN current loop must be designed 

AND FORGET Perform complete yaw damper design 

AND FORGET Define yaw damper feedback equalization 

AND FORGET Define yaw damper gain 

TR-1228-1-11 127 
AND FORGET Yaw damper measurement query has been made 

AND FORGET Yaw damper type has been determined 

AND FORGET Yaw damper measurements are adequate 

AND FORGET Aircraft operation is limited to low AOA 

AND FORGET Aircraft operation is restricted to low AOA 

AND FORGET Yaw damper measurement query has been made 

AND FORGET Yaw damper measurements have been defined 

AND FORGET Rate gyro tilt angle has been queried 

AND FORGET Rate gyro tilt angle has been defined 

AND FORGET Stability axis yaw damper should be designed 

AND FORGET Measurement blending coefficients have been queried 

AND FORGET Yaw damper feedback signal has been defined 

AND FORGET Basic feedback transfer function has been obtained 

AND FORGET rfldr complex dipole is well separated 

AND FORGET Complex dipole is suitable for a yaw damper 

AND FORGET rfldr pole zero configuration has been examined 

AND FORGET Yaw damper washout must be reported 

AND FORGET Yaw damper washout is defined 

AND FORGET Yaw damper open loop transfer function has been created 

AND FORGET Gain selection must be performed 

AND FORGET yaw damper gain is defined 

AND FORGET Yaw damper loop has been designed 

AND FORGET a yaw damper is to be designed 

AND FORGET previous design has been discarded 

AND FORGET previous yaw damper measurement has been discarded 

AND FORGET previous yaw damper washout has been discarded 

AND FORGET previous yaw damper gain has been discarded 

AND FORGET yaw damper is ready for assessment 

AND FORGET Current system assessment model is setup 

AND FORGET requirement comparison is complete 

AND FORGET System model must be generated 

AND FORGET FCS parameters are set 

AND FORGET Return to calling expert 

AND FORGET System model must be generated 

AND FORGET System model has been generated 

AND FORGET Specified system transfer function has been transmitted 

AND FORGET System poles and zeros must be identified 

AND FORGET Basic feedback transfer function has been obtained 

AND CHAIN C:\FCSXPRT\YAWDMPR 

RULE for initiating roll damper design 

IF Current loop IS roll damper 

THEN current loop must be designed 

AND FORGET Define roll damper feedback equalization 

AND FORGET Define lead time constant 

AND FORGET Define lag time constant 

AND FORGET Define roll damper gain 

AND FORGET Roll damper lead inverse time constant has been defined 

AND FORGET Roll damper lag inverse time constant has been defined 

AND FORGET Define roll damper feedback equalization 

AND FORGET Pure gain roll damper O.L. transfer function is generated 

AND FORGET Pure gain roll damper has standard root locus topology 

TR-1228-1-11 128 
AND FORGET Roll damper requires lead equalization 

AND FORGET Dutch roll locus goes to rigid body zero 

AND FORGET Pure gain roll damper root locus has been examined 

AND FORGET Roll damper requires lag equalization 

AND FORGET Roll damper feedback equalization has been defined 

AND FORGET Roll damper open loop transfer function is created 

AND FORGET Gain selection must be performed 

AND FORGET roll damper gain is defined 

AND FORGET roll damper loop has been designed 

AND FORGET roll damper is ready for assessment 

AND FORGET Current system assessment model is setup 

AND FORGET requirement comparison is complete 

AND FORGET System model must be generated 

AND FORGET FCS parameters are set 

AND FORGET Return to calling expert 

AND FORGET System model must be generated 

AND FORGET System model has been generated 

AND FORGET Specified system transfer function has been transmitted 

AND FORGET System poles and zeros must be identified 

AND FORGET Basic feedback transfer function has been obtained 

AND CHAIN C:\FCSXPRT\ROLLDMPR 

................................................................... 

! 

! Rule for adequate design of current architecture 

RULE for adequacy of current FCS design 

IF Current architecture IS RD&YD 

AND yaw damper loop assessment IS assessed ana adequate 

AND roll damper loop assessment IS assessed and adequate 

THEN Current architecture has been designed 

AND RD&YD assessment IS assessed and adequate 

AND DISPLAY Current system 

! Save context 

AND CHAIN C:\FCSXPRT\GENERATE 

! 

............................................................ 

! 

! 

! Information Display Text 

DISPLAY Current system 

0 The current loop structure recommended for assessment for control of the 

(Degrees of freedom for control) of a (aircraft type) is: 

Current architecture: 

[Current architecture] 

TR-1228-1-11 129 
Current loop: 

[Current loop] 

To continue, press F2 

TEXT RD&M 

Roll damper plus yaw damper 

TEXT RDEGB-DR 

Roll damper plus sideslip to rudder 

TEXT RD&AY-DR 

Roll damper plus lateral acceleration to rudder 

TEXT B-DR 

Sideslip to rudder 

TEXT AY-DR 

Lateral acceleration to rudder 

! 

END 

TR-1228-1-11 130 
YAWDMPR,PRL 

TR-1228-1-11 131 
! "YAWDMPR . PRL" 

! 

! SYSTEMS TECHNOLOGY, INC Hawthorne, CA 

! 

TITLE YAW DAMPER EXPERT (YAWDMPR) DISPLAY 

This expert assists in the design of yaw damper loops. 

To continue with yaw damper design, PRESS F3 

............................................................... 

I 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

NUMERIC dutch roll damping ratio 

................................................................ 

! I ! Parameter Initialization Statements 

! 

I 

FORGET Perform complete yaw damper design 

AND Define yaw damper feedback equalization 

AND Define yaw damper gain 

AND Yaw damper measurement query has been made 

AND Yaw damper type has been determined 

AND Yaw damper measurements are adequate 

AND Aircraft operation is limited to low AOA 

AND Aircraft operation is restricted to low AOA 

AND 

AND Rate gyro tilt angle has been queried 

AND Rate gyro tilt angle has been defined 

AND 

AND 

AND Yaw damper feedback signal has been defined 

AND Basic feedback transfer function has been obtained 

AND rfldr complex dipole is well separated 

AND Complex dipole is suitable for a yaw damper 

AND 

AND 

AND Yaw damper washout is defined 

AND Yaw damper open loop transfer function has been created 

AND 

Yaw damper measurement query has been made 

Stability axis yaw damper should be designed 

Measurement blending coefficients have been queried 

rfldr pole zero configuration has been examined 

Yaw damper washout must be reported 

Gain selection must be performed 

TR-1228-1-11 132 
AND 

AND 

AND 

! 

! 

! 

! 

AND 

AND 

AND . 

AND 

yaw damper gain is defined 

Yaw damper loop has been designed 

a yaw damper is to be designed 

AND previous design has been discarded 

AND 

AND 

AND 

yaw damper is ready for assessment 

Current system assessment model is setup 

requirement comparison is complete 

previous yaw damper measurement has been discarded 

previous yaw damper washout has been discarded 

previous yaw damper gain has been discarded 

Yaw damper type 

................................................................ 

! 

! Control Element Selectors 

THRESHOLD - 60 

CONFIDENCE OFF 

CONFIDENCE Aircraft operation is limited to low AOA 

GOALSELECT ON 

UNKNOWN CONTINUE 

$ExHAUSTv. SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The WULTI" Declaration of multiattributed objects is stored in the 

! 

! during compilation. 

"include" file named "MULTI.SHR" and combined with this knowledge base 

$MULTI . SHR 

I 

................................................................ 

! 

! 

! Goal Outline 

1. Perform complete yaw damper design 

1.1 Yaw damper measurement query has been made 

1.1.1 Yaw damper measurements are adequate 

1.1.1.1.1 Yaw damper washout is defined 

Yaw damper gain is defined 

1.1.1.1 Yaw damper feedback signal has been defined 

1.1.1.1.1.1 

1.1.1.1.1.1.1 Yaw damper is ready for assessment 

1.1.1.1.1.1.1.1 Yaw damper loop assessment IS WHAT 

TR-1228-1-11 133 
2. Define yaw damper feedback equalization 

Yaw damper is ready for assessment 

2.1 Yaw damper washout is defined 

2.1.1 

2.1.1.1 Yaw damper loop assessment IS WHAT 

3. Define yaw damper gain 

3.1 Yaw damper gain is defined 

3.1.1 Yaw damper is ready for assessment 

3.1.1.1 Yaw damper loop assessment IS WHAT 

! 

! 

! Rules 

! 

................................................................ 

! 

! Rules for yaw damper measurement query 

~ 

I 

~ ! 

I 

RULE for measurement selection by user 

! 

! 

! 

IF ASK Yaw damper measurement 

AND Yaw damper measurement IS Yaw rate 

THEN Yaw damper measurement query has been made 

! AND N5 :- CONF(Yaw damper measurement IS Yaw rate) 

! AND N6 := Cr)NF(Yaw damper measurement IS Roll rate) 

! AND DISPLAY measur’ement summary - 

ELSE NOT Yaw damper measurement query has been made 

AND DISPLAY Yaw rate necessary 

AND LOOP 

Asks user to specify measurements to be used but insures that, if 

any are selected, yaw rate is included. 

indicate any measurement as unknown. 

Alternatively user can 

RULE for unknown measurements 

! 

! any measurement as unknown 

IF CONF(Yaw damper measurement IS Yaw rate) = -2 

OR CONF(Yaw damper measurement IS Roll rate) = -2 

THEN Yaw damper measurement query has been made 

AND N5 :- CONF(Yaw damper measurement IS Yaw rate) 

AND N6 :- CONF(Yaw damper measurement IS Roll rate) 

AND DISPLAY measurement summary 

Notes that measurement query has been made even if user indicates 

................................................................. 

I ! Rules for yaw damper type 

RULE for yaw damper type 

IF Yaw damper measurement IS yaw rate 

AND Yaw damper measurement IS roll rate 

THEN Yaw damper type has been determined ~ 

I 

I AND Yaw damper type IS Yaw roll type 

I TR-1228-1-11 134 
AND DISPLAY Yaw roll type display 

RULE for yaw damper type 

IF Yaw damper measurement IS yaw rate 

AND NOT Yaw damper measurement IS roll rate 

THEN Yaw damper type has been determined 

AND Yaw damper type IS Yaw only type 

AND DISPLAY Yaw only type display 

5 

................................................................. 

! 

! Rules for measurement adequacy 

RULE for measurement adequacy 

IF Yaw damper type IS Yaw roll type 

THEN Yaw damper measurements are adequate 

RULE for measurement adequacy for low AOA 

IF Aircraft operation is limited to low AOA 

AND Yaw damper type IS Yaw only type 

OR Yaw damper type IS Yaw roll type 

THEN Yaw damper measurements are adequate 

RULE for measurement inadequacy 

IF NOT Aircraft operation is limited to low AOA 

AND Yaw damper type IS Yaw only type 

THEN NOT Yaw damper measurements are adequate 

AND DISPLAY Roll measurement reGuired 

AND CYCLE 

RULE for low AOA operation query 

IF ASK Aircraft operation is restricted to low AOA 

AND Aircraft operation is restricted to low AOA 

THEN Aircraft operation is limited to low AOA 

ELSE NOT Aircraft operation is limited to low AOA 

RULE for low AOA operation 

IF Aircraft classification IS Class IV 

THEN NOT Aircraft operation is limited to low AOA CF 95 

AND DISPLAY Class IV AOA range 

................................................................. 

! 

! Rules for using tilted rate gyros 

RULE for gyro tilt query 

IF Yaw damper type IS Yaw only type 

AND DISPLAY Gyro tilt 

AND ASK Rate gyro tilt angle 

THEN Rate gyro tilt angle has been queried 

TR-1228-1-11 135 
RULE for gyro tilt angle 

IF Rate gyro tilt angle has been queried 

AND CONF(Rate gyro tilt angle) > 0 

THEN Rate gyro tilt angle has been defined 

AND N7 :- Rate gyro tilt angle 

RULE for unknown gyro tilt angle 

IF Yaw damper type IS Yaw only type 

AND CONF(Rate gyro tilt angle) - -2 

THEN Stability axis yaw damper should be designed 

AND Rate gyro tilt angle :- alpha0 

AND Rate gyro tilt angle has been defined 

AND N7 :- Rate gyro tilt angle 

................................................................. 

! 

! Rules for blending yaw and roll rates in Yaw roll type yaw dampers 

RULE for measurement blending query 

IF Yaw damper type IS Yaw roll type 

AND DISPLAY Blending coefficients 

AND ASK Yaw rate blending coefficient 

AND ASK Roll rate blending coefficient 

THEN Measurement blending coefficients have been queried 

RULE for measurement blending coefficients 

IF Measurement blending coefficients have been queried 

AND CONF(Yaw rate blending coefficient) > 0 

AND GONF(Rol1 rate blending coefficient) > 0 

THEN Measurement blending coefficients have been defined 

AND N4 :- Yaw rate blending coefficient 

AND N3 :- Roll rate blending coefficient 

AND S1 :- "Kpblend - 'I 

AND S2 :- "Krblend - 

RULE for measurement blending coefficients 

IF Yaw damper type IS Yaw roll type 

THEN Stability axis yaw damper should be designed 

AND Yaw rate blending coefficient := COS(alpha0/57.3) 

AND Roll rate blending coefficient := -SIN(alpha0/57.3) 

AND Measurement blending coefficients have been defined 

AND N4 :- Yaw rate blending coefficient 

AND N3 :- Roll rate blending coefficient 

AND S1 := "-Sin(A0A) =It 

AND S2 := "COS(AOA) - " 

................................................................ 

1 

! 

! Rules for definition of yaw damper feedback signal 

RULE for yaw damper signal 

IF Yaw damper measurements are adequate 

TR-1228-1-11 136 
AND Yaw damper type IS Yaw only type 

AND Rate gyro tilt angle has been defined 

THEN Yaw damper feedback signal has been defined 

AND DISPLAY Yaw damper summary #1 

RULE for yaw damper signal 

AND Yaw damper type IS Yaw roll type 

AND Measurement blending coefficients have been defined 

THEN Yaw damper feedback signal has been defined 

AND DISPLAY Yaw damper summary #2 

.I IF Yaw damper measurements are adequate 

J 

.................................................................. 

! Rules for generating the basic feedback transfer function 

I 

RULE for feedback transfer function 

IF Yaw damper type IS Yaw only type 

AND Yaw damper feedback signal has been defined 

THEN System model must be generated 

AND Expert requesting SYSMOD IS YAWDMPR expert 

AND FORGET FCS parameters are set 

AND FORGET System model has been generated 

AND FORGET Return to calling expert 

AND Calling expert IS YAWDMPR expert 

AND CHAIN C:\FCSXPRT\SYSMOD 

RULE for feedback transfer function 

IF Yaw damper type IS Yaw roll type 

AND Yaw damper feedback signal has been defined 

THEN System model must be generated 

AND Expert requesting SYSMOD IS YAWDMPR expert 

AND FORGET FCS parameters are set 

AND FORGET System model has been generated 

AND FORGET Return to calling expert 

AND Calling expert IS YAWDMPR expert 

AND CHAIN C:\FCSXPRT\SYSMOD 

RULE for bringing open loop rfllr into knowledge base 

IF System model must be generated 

AND System model has been generated 

THEN Specified system transfer function has been transmitted 

AND FORGET Return to calling expert 

AND FORGET Specified system transfer function has been transmitted 

AND Transfer function $$g filename :- "G26032" 

AND CHAIN C:\FCSXPRT\TFEXT 

RULE for identifying the poles and zeros 

IF Specified system transfer function has been transmitted 

THEN System poles and zeros must be identified 

AND Basic feedback transfer function has been obtained 

AND FORGET System poles are identified 

TR-1228-1-11 137 
AND FORGET Return to calling expert 

AND CHAIN C:\FCSXPRT\ROOTID 

AND System poles are identified 

................................................................ 

! 

! 

! 

Rules for determining the suitability of the basic feedback transfer 

function with respect to positioning of complex dipole. 

RULE for basic feedback signal suitability 

IF Basic feedback transfer function has been obtained 

AND ASK rfldr complex dipole is well separated 

AND rfldr complex dipole is well separated 

THEN Complex dipole is suitable for a yaw damper 

ELSE DISPLAY Unsuitable complex dipole 

AND CYCLE 

RULE for examining rfldr pole zero configuration 

IF CONF(rf1dr complex dipole is well separated) - -2 

! AND DISPLAY 

! Routine to display root locus of rfldr ($$g26032) 

! 

THEN rfldr pole zero configuration has been examined 

AND ASK rfldr complex dipole is well separated 

RULE for suitable dipole 

IF rfldr pole zero configuration has been examined 

AND rfldr complex dipole is well separated 

THEN Complex dipole is suitable for a yaw damper 

RULE for suitable dipole 

IF rfldr pole zero configuration has been examined 

AND NOT rfldr complex dipole is well separated 

THEN NOT Complex dipole is suitable for a yaw damper 

AND DISPLAY Unsuitable complex dipole 

AND CYCLE 

RULE for suitable yaw damper feedback signal 

IF Wrs/Wd C .6 

AND CONF(rf1dr complex dipole is well separated) = -2 

THEN rfldr complex dipole is well separated CF 80 

AND Complex dipole is suitable for a yaw damper 

................................................................. 

! 

! Rules for initial setting of yaw damper washout 

RULE for requesting washout time constant 

IF Complex dipole is suitable for a yaw damper 

AND CONF(dutch roll damping ratio assessment IS adequate) < 0 

AND CONF(dutch roll damping ratio assessment IS too low) < 0 

AND ASK Yaw damper washout inverse time constant 

TR-1228-1-11 138 
AND Yaw damper washout inverse time constant > 0.0 

THEN Yaw damper washout must be reported 

RULE for setting initial washout time constant 

IF Complex dipole is suitable for a yaw damper 

AND CONF(Yaw damper washout inverse time constant) 9 -2 

AND CONF(dutch roll damping ratio assessment IS adequate) < 0 

AND CONF(dutch roll damping ratio assessment IS too low) < 0 

THEN Yaw damper washout must be reported 

AND DISPLAY Recommended washout 

* AND Yaw damper washout inverse time constant :- Wd/2 

................................................................. 

1 

! 

! Rules for adjusting previous washout time constant 

RULE for examining yaw damper root locus 

IF CONF(dutch roll damping ratio assessment IS too low) > 0 

AND DISPLAY Yaw damper root locus 

! AND CHAIN C:\STI\CC.EXE 

AND ASK Yaw damper washout inverse time constant 

AND Yaw damper washout inverse time constant > 0.0 

THEN Yaw damper washout must be reported 

RULE for adjusting washout time constant 

IF Complex dipole is suitable for a yaw damper 

AND CONF(dutch roll damping ratio assessment IS too low) > 0 

AND Yaw damper washout inverse time constant > Wd/3 

THEN Yaw damper washout must be reported CF 75 

AND Yaw damper washout inverse time constant :- -(Wd/2) + : 

Yaw damper washout inverse time constant 

RULE for adjusting washout time constant 

IF Complex dipole is suitable for a yaw damper 

AND CONF(dutch roll damping ratio assessment IS too low) > 0 

AND Yaw damper washout inverse time constant <- Wd/3 

THEN Yaw damper washout must be reported CF 75 

AND Yaw damper washout inverse time constant :- (Wd/2) + : 

Yaw damper washout inverse time constant 

RULE yaw damper summary display 

IF Yaw damper type IS Yaw only type 

AND Yaw damper washout must be reported 

THEN Yaw damper washout is defined 

AND Yaw damper washout time constant :- : 

AND N2 :- Yaw damper washout inverse time constant 

AND DISPLAY yaw damper summary #l 

RULE yaw damper summary display 

IF Yaw damper type IS Yaw roll type 

AND Yaw damper washout must be reported 

, 1/(Yaw damper washout inverse time constant) 

. 

TR-1228-1-11 139 
THEN Yaw damper washout is defined 

AND Yaw damper washout time constant :- : 

1/(Yaw damper washout inverse time constant) 

AND N2 :- Yaw damper washout inverse time constant 

AND DISPLAY yaw damper summary #2 

................................................................. 

! 

! Rules for setting yaw damper gain 

RULE for generating open loop transfer function 

IF Yaw damper washout is defined 

THEN System model must be generated 

AND Yaw damper open loop transfer function has been generated ! ****** 

AND Expert requesting SYSMOD IS YAWDMPR expert 

AND FORGET FCS parameters are set 

AND FORGET System model has been generated 

AND FORGET Return to calling expert 

AND Calling expert IS YAWDMPR expert 

AND CHAIN C:\FCSXPRT\SYSMOD 

RULE for bringing open loop transfer function into knowledge base 

IF System model must be generated 

AND System model has been generated 

AND Yaw damper open loop transfer function has been generated ! ****** 

THEN Yaw damper open loop transfer function has been transmitted 

AND FORGET Return to calling expert 

AND FORGET Specified system transfer function has been transmitted 

AND Transfer .function $$g filename :- "G26052" 

AND CHAIN C:\FCSXPRT\TFEXT 

! ******* 

RULE for identifying the poles and zeros 

IF Yaw damper open loop transfer function has been transmitted ! ******* 

THEN System poles and zeros must be identified 

AND Yaw damper open loop transfer function has been created 

AND FORGET System poles are identified 

AND FORGET Return to calling expert 

AND CHAIN C:\FCSXPRT\ROOTID 

AND System poles are identified 

RULE For obtaining yaw damper gain 

IF Yaw damper open loop transfer function has been created 

AND DISPLAY Gain selection 

THEN Gain selection must be performed 

AND FORGET Specify loop gain directly 

AND FORGET Loop gain has been specified directly 

AND FORGET Examine Root Locus to set the gain 

AND FORGET Loop gain has been specified from root locus 

AND FORGET Examine Bode siggy to set the gain 

AND FORGET Loop gain has been specified from Bode Siggy 

AND FORGET Loop gain has been specified 

AND FORGET Loop gain is defined 

TR-1228-1-11 140 
AND FORGET Terminate gain selection 

AND FORGET Return to calling module 

AND CHAIN C:\FCSXPRT\GAINSEL 

AND Yaw damper gain is defined 

I-------------------------------------------------------------- 

! 

! 

RULE for completion of a yaw damper design 

IF Yaw damper type IS Yaw only type 

AND Yaw damper feedback signal has been defined 

AND Yaw damper washout is defined 

AND Yaw damper gain is defined 

THEN Yaw damper loop has been designed 

AND yaw damper gain :- loop gain 

AND N1 :- Yaw damper gain 

AND DISPLAY Yaw damper summary #1 

AND FORGET a yaw damper is to be designed 

! 

! 

! 

! 

Rules for completion of yaw damper design 

AND FORGET previous design has been discarded 

AND FORGET prev€ous yaw damper measurement has been discarded 

AND FORGET previous yaw damper washout has been discarded 

AND FORGET previous yaw damper gain has been discarded 

RULE for completion of a yaw damper design 

IF Yaw damper type IS Yaw roll type 

AND Yaw damper feedback signal has been defined 

AND Yaw damper washout is defined 

AND Yaw damper gain is defined 

THEN Yaw damper loop has been designed 

AND yaw damper gain :- loop gain 

AND N1 :- Yaw damper gain 

AND DISPLAY Yaw damper summary #2 

AND FORGET a yaw damper is to be designed 

! 

! 

! 

! 

. 

AND FORGET previous design has been discarded 

AND FORGET previous yaw damper measurement has been discarded 

AND FORGET previous yaw damper washout has been discarded 

AND FORGET previous yaw damper gain has been discarded 

................................................................. 

! 

! Rules for assessing yaw damper design 

RULE for setting up current system assessment model 

IF Yaw damper loop has been designed 

AND DISPLAY design assessment 

THEN System model must be generated 

AND Yaw damper assessment dynamics have been generated 

AND Yaw damper loop connection IS closed 

AND Expert requesting SYSMOD IS YAWDMPR expert 

AND FORGET FCS parameters are set 

AND FORGET System model has been generated 

. 

!******** 

TR-1228-1-11 141 
AND FORGET Return to calling expert 

AND Calling expert IS YAWDMPR expert 

AND CHAIN C:\FCSXPRT\SYSMOD 

RULE for bringing closed loop SrflSr into knowledge base 

IF System model must be generated 

AND System model has been generated 

AND Yaw damper assessment dynamics have been generated 

THEN Specified system transfer function has been transmitted 

AND Yaw damper assessment dynamics have been transmitted 

AND FORGET Return to calling expert 

AND FORGET Specified system transfer function has been transmitted 

AND Transfer function $$g filename :- "G26052" ! $$gname ??????? 

AND CHAIN C:\FCSXPRT\TFEXT 

!******** 

!******** 

RULE for identifying the closed loop poles and zeros 

IF Specified system transfer function has been transmitted 

AND Yaw damper assessment dynamics have been transmitted 

THEN System poles and zeros must be identified 

AND Current system assessment model is setup 

AND System poles and zeros have been identified 

AND Yaw damper dynamics are ready for assessment !********* 

AND FORGET System poles are identified 

AND FORGET Return to calling expert 

AND CHAIN C:\FCSXPRT\ROOTID 

AND DISPLAY dynamic characteristics 

RULE fox assessing the closed loop dynamics 

IF System poles and zeros have been identified 

AND Yaw damper dynamics are ready for assessment 

THEN Yaw damper is ready for assessment 

!******** 

!********* 

AND 

AND 

AND 

I AND 

AND 

AND 

! 

AND 

AND 

~ 

I ! 

FORGET dutch roll d-amping ratio has been assessed 

FORGET dutch roll mode dynamics are adequate 

FORGET dutch roll mode has been compared with the requirements 

FORGET modal dynamics are adequate 

FORGET system has been compared with the requirements 

FORGET requirement comparison is complete 

CHAIN C:\FCSXPRT\ASSESS 

DISPLAY dynamics assessment 

AND FORGET dutch roll damping ratio assessment 

AND System requirement check has been made ! TEMPORARY 

.................................................................. 

! 

! 

! is completed 

Rules for deciding what to do after yaw damper assessment . 

RULE for treating an inadequate yaw damper design 

IF requirement comparison is complete 

AND dutch roll damping ratio assessment IS too low 

THEN Yaw damper loop assessment IS assessed and inadequate 

TR-1228-1-11 142 
AND DISPLAY Inadequate yaw damper 

AND CYCLE 

RULE for treating an adequate yaw damper design 

IF requirement comparison is complete 

AND dutch roll damping ratio assessment IS adequate 

THEN Yaw damper loop assessment IS assessed and adequate 

AND DISPLAY Adequate yaw damper 

AND FORGET Current loop has been specified 

AND FORGET Current loop connections are set for design 

AND FORGET Current system design model is setup 

AND FORGET Current loop must be designed 

AND FORGET Current architecture has been designed 

AND CHAIN C:\FCSXPRT\DESIGN 

- 

! 

! 

! Information Display Text 

DISPLAY Yaw rate necessary 

To construct a practical yaw damper, yaw rate must be one of the measurements 

used in the design. 

To continue, press F2 

DISPLAY Measurement summary 

Summary of measurements selected for use in the yaw damper: 

Measurement Confidence factor for selection 

Yaw rate ~5 I 

Roll rate [N61 

To continue, press F2 

DISPLAY Yaw roll type display 

Current yaw damper design uses both yaw and roll rate measurements 

TR-1228-1-11 

~ 

143 
dr 

)- > 

h - rb + Gyro + 

Aircraft 

and 

Sensors 

blend coeff 

blend coeff 

rb 

Effective yaw rate 

feedback signal 

rf 

Equalization 

To continue, press F2 

DISPLAY Yaw only type display 

Current yaw damper design uses only a yaw rate measurement 

I rwo Feedback 

Equalization 

1 I 

To continue, press F2 

DISPLAY Roll measurement required 

Use of roll rate in addition to yaw rate is indicated. 

Since it appears that the [aircraft designation] operates over a wide range of 

angle of attack, significant movement of the complex yaw rate zero can be 

expected. 

will probably not be adequate and a roll rate measurement should also be used. 

Thus use of only a yaw rate measurement (regardless of gyro tilt) 

To restart the yaw damper design, press F2 

c 

TR-1228-1-11 144 
DISPLAY Class IV AOA range 

Class IV aircraft such as this [aircraft type] are highly maneuverable and 

generally operate over a wide angle of attack range. 

To continue, press F2 I’ 

I 

IC DISPLAY Yaw damper summary #1 

Current yaw damper 

? 

To continue, press F2 

DISPLAY Yaw damper summary #2 

Current yaw damper 

roll rate blend 

To continue, press F2 

TR-1228-1-11 14 5 
DISPLAY Gyro tilt 

RATE GYRO INCLINATION 

You must now specify the orientation of the yaw damper rate gyro in the 

aircraft body (fuselage reference line) axis system by specifying the 

inclination or "tilt" angles in degrees. When prompted: 

Enter a numerical value and press ENTER key OR 

If the tilt angle is unknown, press F2 

To continue, press F2 

Since only yaw rate is to be used in the yaw damper design, the inclination of 

the gyro significantly affects the suitability of the feedback signal. The 

gyro tilt angle is the angle between the sensitive axis of the gyro and the 

aircraft body 2 axis, positive when the gyro axis is aft of the aircraft Z 

axis. 

DISPLAY Blending coefficients 

YAW and ROLL RATE BLENDING COEFFICIENTS 

Enter yaw and roll rate blending coefficients when prompted: 

Enter a numerical value and press ENTER key OR 

If the coefficient is unknown, press F2 

Roll --+ 

rate + Roll rate 

>t blend coeff 7 

+v 

+ 

rf 

To continue, press F2 

DISPLAY Unsuitable complex dipole 

The complex Wr(Wd dipole in the effective yaw rate to rudder transfer function 

(rfldr) must be well separated to create a good yaw damper. 

not appear to be the case, adjustments in the feedback signal will have to be 

made. 

Since this does 

TR-1228-1-11 146 
To revise the design, press F2 

DISPLAY Yaw damper root locus 

The dutch roll damping ratio for the current yaw damper design is 

[dutch roll damping ratio]. 

To view the yaw damper root locus, press F2 

DISPLAY Recommended washout 

Yaw Damper Washout 

The yaw damper washout inverse time constant should generally be placed about 

an octave below the dutch roll mode which is [Wd(9,2)] rad/sec. 

Thus an initial washout inverse time constant of 

[yaw damper washout inverse time constant] rad/sec has been selected. 

To continue, press F2 

DISPLAY Gain selection 

The open loop transfer function for the yaw damper is now defined and the final 

step is selection of the loop gain. 

To select the loop gain, press F2 

DISPLAY dynamic characteristics 

The dynamics characteristics have been obtained for the system 

To continue, Press F2 

DISPLAY dynamics assessment 

The assessment of the system dynamics indicates the following problems: 

TR-1228-1-11 

To continue, Press F2 

147 
DISPLAY design assessment 

x 

Well separated 

complex dipole 

The yaw damper design is now complete. 

Im 

To begin assessment of the design, Press F2 

DISPLAY Inadequate yaw damper 

Assessment of the current yaw damper design indicates that the dutch roll 

damping ratio is [dutch roll damping ratio assessment] 

x 

Complex dipole 0 

NOT well separated 

I Thus the yaw damper loop is [Yaw damper loop assessment] 

Im 

The yaw damper design should be revised. 

increased, but modification of the washout may also be necessary. 

As a minimum the gain should be 

To begin design revision, press F2 

DISPLAY Adequate yaw damper 

Assessment of the current yaw damper design indicates that the dutch roll 

damping ratio is [dutch roll damping ratio assessment] 

Thus the yaw damper loop is [Yaw damper loop assessment] 

To continue the FCS design, Press F2 

I 

EXPAND rfldr complex dipole is well separated 

, The pole and zero in the complex dutch roll dipole of the effective 

yaw rate to rudder transfer function (rfldr) must be well separated to 

create a good yaw damper. 

r/hr zero 

I O1 

To continue press F8 

EXPAND Aircraft operation is restricted to low AOA 

148 TR-1228-1-11 
Operation 

characteri 

stability 

angles of 

at low angles of attack (AOA) implies that the aircraft’s aerodynamic 

.stcs are quite linear with angle of attack and that differences in 

axis and body axis quantities tend to be small. 

attack means that the operational range of angle attack is small. 

Restriction to low 

To continue press F8 

! 

END 

TR-1228-1-11 149 
TR-1228-1-11 

ROLLDMPR.PRL 

150 
! "ROLLDMPR . PRL" 

! 

! SYSTEMS TECHNOLOGYl INC Hawthorne, CA 

! 

TITLE ROLL DAMPER EXPERT (ROLLDMPR) DISPLAY 

This expert assists in the design of roll damper loops. 

To continue with roll damper design, PRESS F3 

............................................................... 

! Shared Facts Declarations 

! 

I The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation 

I 

$SHAREFCT.SHR 

................................................................ 

! 

! Data Type Declarations 

! 

................................................................ 

! 

.! Parameter Initialization Statements 

................................................................ 

! 

! Control Element Selectors 

I 

THRESHOLD - 60 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV.SHR 

! .................................................................... 

! 

! Multiattributed Objects Declarations' 

! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI. SHR" and combined with this knowledge base 

! during compilation. 

$MULTI . SHR 

.............................................................. 

! 

! Goal Outline 

TR-1228-1-11 151 
1. Define roll damper feedback equalization 

1.1 Define lead time constant 

1.1.1 Pure gain roll damper OLTF has been generated ! ****** 

1.1.1.1 roll damper feedback equalization has been defined 

1.1.1.1.1 roll damper is ready for assessment 

1.1.1.1.1.1 roll damper loop assessment IS WHAT 

1.2 Define lag time constant 

1.2.1 Pure gain roll damper OLTF has been generated ! ****** 

1.2.1.1 roll damper feedback equalization has been defined 

1.2.1.1.1 roll damper is ready for assessment 

1.2.1.1.1.1 roll damper loop assessment IS WHAT 

2. Define roll damper gain 

2.1 roll damper gain is defined 

2.1.1 roll damper is ready for assessment 

2.1.1.1 roll damper loop assessment IS WHAT 

! 

1 Rules 

! 

................................................................. 

! 

! Rules for obtaining pure gain roll damper open loop model 

RULE for generating unequalized open loop pbl6a transfer function 

IF Define lead time constant 

OR Define lag time constant 

THEN System model must be generated 

AND Expert requesting SYSMOD IS ROLLDMPR expert 

AND FORGET FCS parameters are set 

AND FORGET System model has been generated 

AND FORGET Return to calling expert 

AND Calling expert IS ROLLDMPR expert 

AND CHAIN C:\FCSXPRT\SYSMOD 

RULE for bringing unequalized open loop pbl6a into knowledge base 

IF System model must be generated 

AND System model has been generated 

THEN Specified system transfer function has been transmitted 

AND FORGET Return to calling expert 

AND FORGET Specified system transfer function has been transmitted 

AND Transfer function $$g filename := "G26011" 

AND CHAIN C:\FCSXPRT\TFEXT 

RULE for identifying the poles and zeros 

IF Specified system transfer function has been transmitted 

THEN System poles and zeros must be identified 

AND Basic feedback transfer function has been obtained 

TR-1228-1-11 152 
AND Pure gain roll damper OLTF has been generated 

AND FORGET System poles are identified 

AND FORGET Return to calling expert 

AND CHAIN C:\FCSXPRT\ROOTID 

AND System poles are identified 

................................................................. 

! 

! Rules for setting equalization from user specification 

RULE for lead inverse time constant query 

IF ASK Roll damper lead inverse time constant 

AND Roll damper lead inverse time constant > 0 

AND CONF(Rol1 damper lead inverse time constant) > 0 

THEN Roll damper lead inverse time constant has been defined 

AND N21 := Roll damper lead inverse time constant 

! AND DISPLAY 

! ELSE DISPLAY Positive time constant 

! AND LOOP 

RULE for lag time constant query 

IF ASK Roll damper lag inverse time constant 

AND Roll damper lag inverse time constant > 0 

AND CONF(Rol1 damper lag inverse time constant) > 0 

THEN Roll damper lag inverse time constant has been defined 

AND N22 :- Roll damper lag inverse time constant 

! AND DISPLAY 

! ELSE DISPLAY Positive time constant 

! AND LOOP 

................................................................ 

! 

! Rules for equalization form required 

RULE for generating pure gain open loop transfer function 

IF Define roll damper feedback equalization 

! AND ACTIVATE C:\CC.EXE 

THEN Pure gain roll damper O.L. transfer function is generated 

RULE for lead equalization 

IF Pure gain roll damper has standard root locus topology 

THEN NOT Roll damper requires lead equalization 

ELSE Roll damper requires lead equalization 

RULE for standard pure gain root locus 

IF CONF(Pure gain roll damper has standard root locus topology) - -2 

AND DISPLAY Standard root locus 

! AND ACTIVATE C:\STI\CC.EXE 

AND ASK Dutch roll locus goes to rigid body zero 

THEN Pure gain roll damper root locus has been examined 

e AND Pure gain roll damper O.L. transfer function is generated 

TR-1228-1-11 153 
RULE for standard root locus topology 

IF Pure gain roll damper root locus has been examined 

AND Dutch roll locus goes to rigid body zero 

THEN Pure gain roll damper has standard root locus topology 

RULE for lag equalization 

IF Roll damper requires lead equalization 

THEN Roll damper requires lag equalization 

RULE for lead placement 

IF Roll damper requires lead equalization 

AND CONF(Rol1 damper lead inverse time constant) = -2 

AND Pure gain roll damper O.L. transfer function is generated 

AND DISPLAY Lead placement 

! AND ACTIVATE C:\STI\CC.EXE 

AND ASK Roll damper lead inverse time constant 

AND 

THEN Roll damper lead inverse time constant has been defined 

AND N21 := Roll damper lead inverse time constant 

! AND DISPLAY 

Roll damper lead inverse time constant > 0 

RULE for lag placement 

IF Roll damper requires lag equalization 

AND CONF(Rol1 damper lag inverse time constant) - -2 

AND Roll damper lead inverse time constant has been defined 

THEN Roll damper lag inverse time constant has been defined 

AND Roll damper lag inverse time constant := 5*(Roll damper lead : 

inverse time constant) 

AND N22 := Roll damper lag inverse time constant 

AND DISPLAY Recommended lag 

I ! 

! 

................................................................ 

1 

Rule for definition of roll damper feedback equalization 

RULE for equalization definition 

IF Roll damper lead inverse time constant has been defined 

AND Roll damper lag inverse time constant has been defined 

THEN Roll damper feedback equalization has been defined 

AND DISPLAY roll damper summary 

~ 

RULE for no lead required 

IF NOT Roll damper requires lead equalization 

THEN Roll damper feedback equalization has been defined 

AND DISPLAY roll damper summary 

I AND N21 := 999999999999999999999. 

! ................................................................ 

! 

! Rules for setting roll damper gain 

I TR-1228-1-11 154 
RULE for generating open loop transfer function 

THEN System model must be generated 

AND Roll damper open loop transfer function has been generated ! ****** 

AND Expert requesting SYSMOD IS ROLLDMPR expert 

AND FORGET FCS parameters are set 

AND FORGET System model has been generated 

AND FORGET Return to calling expert 

AND Calling expert IS ROLLDMPR expert 

AND CHAIN C:\FCSXPRT\SYSMOD 

I IF Roll damper feedback equalization has been defined 

0 

RULE for bringing open loop equalized pbl6a into knowledge base 

IF System model must be generated 

AND System model has been generated 

AND Roll damper open loop transfer function has been generated ! ****** 

THEN Roll damper open loop transfer function has been transmitted 

AND FORGET Return to calling expert 

AND FORGET Specified system transfer function has been transmitted 

AND Transfer function $$g filename := "G26041" 

AND CHAIN C:\FCSXPRT\TFEXT 

! ******* 

RULE for identifying the poles and zeros 

IF Roll damper open loop transfer function has been transmitted ! ******* 

THEN System poles and zeros must be identified 

AND Roll damper open loop transfer function has been created 

AND roll damper open loop transfer function is created 

AND FORGET System poles are identified 

AND FORGET Return to calling expert . AND CHAIN C:\FCSXPRT\ROOTID 

AND System poles are identified 

RULE For obtaining roll damper gain 

IF roll damper open loop transfer function is created 

THEN Gain selection must be performed 

AND FORGET Specify loop gain directly 

AND FORGET Loop gain has been specified directly 

AND FORGET Examine Root Locus to set the gain 

AND FORGET Loop gain has been specified from root locus 

AND FORGET Examine Bode siggy to set the gain 

AND FORGET Loop gain has been specified from Bode Siggy 

AND FORGET Loop gain has been specified 

AND FORGET Loop gain is defined 

AND FORGET Terminate gain selection 

AND FORGET Return to calling module 

AND CHAIN C:\FCSXPRT\GAINSEL 

AND roll damper gain is defined 

I 

! Rules for completion of roll damper design 

TR-1228-1-11 155 
RULE for completion of a roll damper design 

IF Roll damper feedback equalization has been defined 

AND roll damper gain is defined 

THEN roll damper loop has been designed 

AND roll damper gain := loop gain 

AND N23 :- roll damper gain 

AND DISPLAY roll damper summary 

................................................................. 

! 

! Rules for assessing roll damper design 

RULE for setting up current system assessment model 

IF Roll damper loop has been designed 

AND DISPLAY design assessment 

THEN System model must be generated 

AND Roll damper assessment dynamics have been generated 

AND Roll damper loop connection IS closed 

AND Expert requesting SYSMOD IS ROLLDMPR expert 

AND FORGET FCS parameters are set 

AND FORGET System model has been generated 

AND FORGET Return to calling expert 

AND Calling expert IS ROLLDMPR expert 

AND CHAIN C:\FCSXPRT\SYSMOD 

!******** 

RULE for bringing open loop 6af16a into knowledge base 

IF System model must be generated 

AND System model has been generated 

AND Roll damper assessment dynamics have been generated 

THEN Specified system transfer function has been transmitted 

AND Roll damper assessment dynamics have been transmitted 

AND FORGET Return to calling expert 

AND FORGET Specified system transfer function has been transmitted 

AND Transfer function $$g filename := "G26041" 

AND CHAIN C:\FCSXPRT\TFEXT 

!******** 

!******** 

RULE for identifying the poles and zeros 

IF Specified system transfer function has been transmitted 

AND Roll damper assessment dynamics have been transmitted 

THEN System poles and zeros must be identified 

AND Current system assessment model is setup 

AND System poles and zeros have been identified 

AND Roll damper dynamics are ready for assessment 

AND FORGET System poles are identified 

AND FORGET Return to calling expert 

AND CHAIN C:\FCSXPRT\ROOTID 

AND DISPLAY dynamic characteristics 

!******** 

!********* 

RULE for assessing the closed loop dynamics 

IF System poles and zeros have been identified 

AND Roll damper dynamics are ready for assessment 

THEN Roll damper is ready for assessment 

!********* 

TR-1228-1-11 156 
AND FORGET roll mode time constant has been assessed 

AND FORGET roll subsidence mode dynamics are adequate 

AND FORGET roll subsidence mode has been assessed 

AND FORGET modal dynamics are adequate 

AND FORGET system has been compared with the requirements 

AND FORGET requirement comparison is complete 

! AND FORGET roll subsidence damping ratio assessment 

AND CHAIN C:\FCSXPRT\ASSESS 

! AND System requirement check has been made ! TEMPORARY 

. 

- AND DISPLAY dynamics assessment 

................................................................. 

! 

! Rules for deciding what to do after roll damper assessment is 

! completed 

RULE for treating an inadequate roll damper design 

IF requirement comparison is complete 

AND roll subsidence mode time constant assessment IS too high 

THEN roll damper loop assessment IS assessed and inadequate 

AND DISPLAY Assessment Summary 

AND CYCLE 

RULE for treating an adequate roll damper design 

IF requirement comparison is complete 

AND roll subsidence mode time constant assessment IS adequate 

THEN roll damper loop assessment IS assessed and adequate 

AND DISPLAY Assessment Summary 

AND FORGET Current loop has been specified 

AND FORGET Current loop connections are set for design 

AND FORGET Current system design model is setup 

AND FORGET Current loop must be designed 

AND FORGET Current architecture has been designed 

AND CHAIN C:\FCSXPRT\DESIGN 

I- PPI= --I=--- 

! 

! Information Display Text 

! DISPLAY Positive time constant 

! The roll damper lead and lag time constants must be greater than zero and 

! specified in radians per second. 

! To continue, press F2 

. DISPLAY Lead placement 

If the pure gain roll damper root locus topology is nonstandard, i.e., the 

dutch roll locus does not go into the low frequency "Wphi" complex zero, then 

lead equalization is probably necessary. The lead should be placed below the 

TR-1228-1-11 157 
lowest high frequency (actuator, etc.) mode but well above the rigid body (dutch roll, 

roll subsidence and spiral) modes 

- 

The Bode siggy root locus of the open loop pure gain roll damper will next be 

displayed to aid in placing the lead. . 

[N23(11,2)1 

I 

To continue, press F2 

DISPLAY Standard root locus 

~ If the pure gain roll damper root locus has standard topology the locus from 

the dutch roll pole goes into the low frequency "Wphi" complex zero in the roll 

due to aileron numerator. 

If the root locus topology is nonstandard, the dutch roll locus does not go 

into the Wphi zero and instead departs from the low frequency, rigid body 

dynamics region asymptotically. 

To view the conventional root locus of the open loop pure gain roll damper, 

press F2 

DISPLAY Recommended lag 

For the current roll damper lead placement, the lag should probably be at least 

5 times higher in frequency. Thus the recommended lag inverse time constant is 

[roll damper lag inverse time constant(9,l)l rad/sec. 

DISPLAY roll damper summary . 

Current roll damper 

To continue, press F2 

TR-1228-1-11 158 
! DISPLAY model setup 

! The system to be assessed consists of: 

To continue, Press F2 

~ DISPLAY Assessment Summary 

I Assessment of the 

roll subsidence mode time constant is [roll subsidence mode time constant assessment] 

current roll damper design indicates that the I 

Thus the roll damper loop is [roll damper loop assessment] 

To continue, Press F2 

! 

END 

TR-1228-1-11 159 
TR-1228-1 -I1 

~ 

I 

I 

GAINSEL.PRL 

160 
! "GAINSEL. PRL" 

! 

! SYSTEMS TECHNOLOGY, INC Hawthorne, CA 

TITLE Loop Gain Selection Expert (GAINSEL) DISPLAY 

This expert assists in the selection of gains in loop closures. 

To continue, press F3 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

................................................................ 

! 

! Parameter In i ti a1 iH a t i on s ta tement s 

FORGET Specify loop gain directly 

AND Loop gain has been specified directly 

AND Examine Root Locus to set the gain 

AND 

AND Examine Bode siggy to set the gain 

AND 

AND Loop gain has been specified 

AND Loop gain is defined 

AND Terminate gain selection 

AND Return to calling module 

INIT St7 :-"C:\STI" 

AND St8 : ="CC. EXE" 

AND S t51: ="@ROOTLOC . MAC" 

AND St52:="@BODESIG,MAC" 

REINIT St7 : ="C : \STI" 

AND St8 :-"CC. EXE" 

AND S t51: -"@ROOTLOC . MAC" 

AND S t52 : -"@BODESIG .MAC" 

................................................................ 

! 

! Control Element Selectors 

Loop gain has been specified from root locus 

Loop gain has been specified from Bode Siggy 

# 

TR-1228-1-11 161 
THRESHOLD = 60 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV.SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

I "include" file named "MULTI. SHR" and combined with this knowledge base 

! during compilation. 

$MULTI . SHR 

................................................................ 

! 

! 

! Goal Outline 

1. Specify loop gain directly 

1.1 Loop gain has been specified directly 

1.1.1 Loop gain is defined 

2. Examine Root Locus to set the gain 

2.1 Loop gain has been specified from root locus 

2.1.1 Loop gain is defined 

3. Examine Bode Siggy to set the gain 

3.1 Loop gain has been specified from Bode Siggy 

3.1.1 Loop gain is defined 

4. Terminate gain selection 

4.1 Return to calling module 

! 

! 

! Rules 

! ................................................................. 

! 

! Rules for setting loop gain 

RULE for obtaining loop gain 

IF Specify loop gain directly 

AND ASK Loop gain 

THEN Loop gain has been specified directly 

AND CYCLE 

TR-1228-1-11 162 
RULE for obtaining loop gain from root locus 

IF Examine Root Locus to set the gain 

AND ACTIVATE C:\STI\PROCALL.EXE 

SEND St7 

SEND St8 

SEND Transfer function $$g filename 

AND ASK Loop gain 

THEN Loop gain has been specified from root locus 

AND CYCLE 

* SEND St51 

RULE for obtaining loop gain from Bode siggy 

IF Examine Bode siggy to set the gain 

AND ACTIVATE C:\STI\PROCALL.EXE 

SEND St7 

SEND St8 

SEND St52 

SEND Transfer function $$g filename 

AND ASK Loop gain 

THEN Loop gain has been specified from Bode Siggy 

AND CYCLE 

RULE for ending gain selection 

IF Terminate gain selection 

AND Current loop IS Yaw damper 

THEN Return to calling module 

AND Yaw damper gain is defined 

AND CHAIN C:\FCSXPRT\YAWDMPR 

ELSE Return to calling module 

AND Roll damper gain is defined 

AND CHAIN C:\FCSXPRT\ROLLDMPR 

! 

! Information Display Text 

1 

END 

TR-1228-1-11 163 
TR-1228-1 -It 

SYS MOD. PRL 

164 
! 'I SY SMOD It 

! 

TITLE Creation of Augmented Aircraft Model (SYSMOD) DISPLAY 

This expert generates a transfer function matrix model of the 

. augmented aircraft. 

To continue, press F3 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

................................................................. 

! Parameter Initialization Statements 

I 

! 

INIT Stl := "C:\FCSDAT" 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

AND 

! 

! 

c 

St7 := "C:\STI" 

St8 := "CC.EXE" 

St23 :- "ROLLRFB.TF" 

St24 := "$$G230" 

S t 2 8 : = "YAWRFB . TF" 

St29 := "$$G220" 

St20 := "@FCSMODEL.MAC" 

St21 := "RFTRANS.TMP" 

St25 := "@OLTF.MAC" 

S t33 : - "UROLLRFB . TF" 

St34 := "$$G2311' 

St38 := "UYAWRFB.TF" 

St39 := "$$G221" 

ZERO - 0 

ONE = 1 

Two 2 

FIVE = 5 

SIX - 6 

SEVEN = 7 

ELEVEN = 11 

st22 :- l*$$P21011 

AND NUMl - .3 

AND NUM2 = .2 

! Data file - roll rate feedback TF 

! Program CC roll rate feedback TF name 

! Data file - yaw rate feedback TF 

! Program CC yaw rate feedback TF name 

! Creating the closed loop TF matrix 

! Data file for effective yaw damper 

! Program CC quad name for effective yaw damper 

! Creating open loop transfer functions macro 

! Data file - unity gain roll rate feedback TF 

! Program CC unity gain roll rate feedback TF name 

! Data file - unity gain yaw rate feedback TF 

! Program CC unity gain yaw rate feedback TF name 

! Roll rate feedback gain 

! (.2s+l) term for the roll rate feedback 

TR-1228-1-11 165 
! AND NUM3 = .04 

! AND NUM4 -.8 

! AND NUM5 = 1.5 

! AND Bg - .2164 

! (.04s+l) term for the roll rate feedback 

! Yaw rate feedback gain 

! (s+1.5) term for the yaw rate feedback 

! Rate gyro tilt angle 

REINIT S tl : - "C : \FCSDAT" 

AND St7 :- "C:\STI" 

AND St8 :- "CC.EXE" 

AND St23 := "ROLLRFB.TF" ! Data file - roll rate feedback TF 

AND St24 :- "$$G230" ! Program CC roll rate feedback TF name 

AND St28 :- "YAWRFB.TF" ! Data file - yaw rate feedback TF 

AND St29 := "$$G220" ! Program CC yaw rate feedback TF name 

AND St20 :- "@FCSMODEL.MAC" ! Creating the closed loop TF matrix 

AND St21 :- "RFTRANS.TMP" ! Data file for effective yaw damper 

AND St22 :- "$$P210" ! Program CC quad name for effective yaw damper 

AND St25 := "@OLTF.MAC" ! Creating open loop transfer functions macro 

AND St33 :- "UROLLRFB.TF" ! Data file - unity gain roll rate feedback TF 

AND St34 := "$$G2311' ! Program CC unity gain roll rate feedback TF name 

AND St38 :- "UYAWRFB.TF" ! Data file - unity gain yaw rate feedback TF 

AND St39 := "$$G221" ! Program CC unity gain yaw rate feedback TF name 

AND ZERO - 0 

AND ONE - 1 

AND TWO - 2 

AND FIVE = 5 

AND SIX - 6 

AND ELEVEN - 11 

I AND SEVEN - 7 

! 

! 

................................................................ 

! 

, Control Element Selectors ~ ! 

I THRESHOLD = 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV. SHR 

! .................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI . SHR" and combined with this knowledge base 

! during compilation. 

$MULTI . SHR 

I ................................................................ 

! 

. 

TR-1228-1-11 166 
! 

! Goal Outline 

1. System model has been generated 

1.1 Return to calling expert 

! 

! Rules 

! 

RULE for system model parameter setup 

IF System model must be generated 

AND KPF :- Roll rate blending coefficient 

AND KRF :- Yaw rate blending coefficient 

AND NUM2 :- l/(Roll damper lead inverse time constant) 

AND NUM3 :- l/(Roll damper lag inverse time constant) 

AND NUMl :- Roll damper gain 

AND NUM5 :- Yaw damper washout inverse time constant 

AND "M4 :- yaw damper gain 

THEN FCS parameters are set 

RULE for calling Program 

IF FCS parameters are set 

! 

! 

! Writing the roll rate feedback file that DATOCC. EXE 

! will convert to $$G230 

! 

AND WRITE C:\FCSDAT\ROLLRFB.TF 

DATA SEVEN 

DATA ELEVEN 

DATA TWO 

DATA ZERO 

DATA NUMl 

DATA ONE 

DATA NUM2 

DATA ONE 

DATA ONE 

DATA ONE 

DATA "M3 

DATA ONE 

AND ACTIVATE C:\STI\DATOCC.EXE 

SEND Stl 

SEND St23 

SEND St7 

, SEND St24 

! 

! 

! Writing the yaw rate feedback file that DATOCC.EXE 

! will convert to $$G220 

1 

TR-1228-1-11 167 
! 

! 

AND WRITE C:\FCSDAT\YAWRFB.TF 

DATA SEVEN 

DATA ELEVEN 

DATA TWO 

DATA ZERO 

DATA NUM4 

DATA ONE 

DATA ONE 

DATA ZERO 

DATA ONE 

DATA ONE 

DATA ONE 

DATA "45 

AND ACTIVATE C:\STI\DATOCC.EXE 

SEND Stl 

SEND St28 

SEND St7 

SEND St29 

! 

! 

! Writing the effective yaw rate file that DATOCC.EXE 

! will convert to $$P210 

! 

! 

AND WRITE C:\FCSDAT\RFTRANS.TMP 

DATA ZEPO 

DATA TWO 

DATA TWO 

DATA ONE 

DATA ZERO 

DATA KPF 

I DATA KRF 

AND ACTIVATE C:\STI\DATOCC.EXE 

SEND Stl 

SEND St21 

SEND St7 

SEND St22 

! 

! 

! 

! 

! 

AND ACTIVATE C:\STI\PROCALL.EXE 

SEND St7 

SEND St8 

SEND St20 

THEN System model has been generated 

I 

Creating the closed loop system using the Program CC macro FCSMODEL.MAC 

I TR-1228-1-11 168 
!RULE for creating open loop transfer functions 

!IF System model has been generated 

!THEN open loop transfer functions have been created 

! 

! 

! will convert to $$G231 

! 

! 

AND WRITE C:\FCSDAT\UROLLRFB.TF 

DATA SEVEN 

DATA ELEVEN 

DATA TWO 

DATA ZERO 

DATA ONE 

DATA ONE 

DATA NUM2 

DATA ONE 

DATA ONE 

DATA ONE 

DATA NUM3 

DATA ONE 

AND ACTIVATE C:\STI\DATOCC.EXE 

SEND Stl 

SEND St33 

SEND St7 

SEND St34 

! 

! 

! 

! will convert to $$G221 

! 

! 

AND WRITE C:\FCSDAT\UYAWRFB.TF 

DATA SEVEN 

DATA ELEVEN 

DATA TWO 

DATA ZERO 

DATA ONE 

DATA ONE 

DATA ONE 

DATA ZERO 

DATA ONE 

DATA ONE 

DATA ONE 

DATA NUM5 

AND ACTIVATE C:\STI\DATOCC.EXE $ SEND Stl 

SEND St38 

SEND St7 

SEND St39 

! 

I ! Writing the unity gain roll rate feedback file that DATOCC.EXE 

Writing the unity gain yaw rate feedback file that DATOCC.EXE 

P 

169 TR-1228-1-11 
! 

! 

! 

! 

AND ACTIVATE C:\STI\PROCALL.EXE 

SEND St7 

SEND St8 

SEND St25 

Creating the open loop system using the Program CC macro 0LTF.MAC 

RULE for returning to DESIGN 

IF Expert requesting SYSMOD IS DESIGN expert 

THEN Return to calling expert 

AND CHAIN C:\FCSXPRT\DESIGN 

RULE for returning to YAWDMPR 

IF Expert requesting SYSMOD IS YAWDMPR expert 

THEN Return to calling expert 

AND CHAIN C:\FCSXPRT\YAWDMPR 

RULE for returning to ROLLDMPR 

IF Expert requesting SYSMOD IS ROLLDMPR expert 

THEN Return to calling expert 

AND CHAIN C:\FCSXPRT\ROLLDMPR 

! 

END . 

I TR-1228-1-11 170 
TR-1228-1-11 

TFEXT.PRL 

171 
! "TFEXT . PRL" 

! 

! SYSTEMS TECHNOLOGY, INC Hawthorne, CA 

TITLE Transfer Function Extraction (TFEXT) DISPLAY 

This expert transfers a specified system transfer function, in factored 

form, to an expert. 

To continue, press F3 

I ! 

! 

! expert) to LEVEL5. It is assumed that SYSMOD has just placed the 

! 

This knowledge base functions as a subroutine to transfer transfer 

functions for the augmented airframe system (generated by the SYSMOD 

augmented system transfer functions in Program CC $$G filenames. I 

................................................................ 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

I "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

NUMERIC Number of numerical real zeros 

AND Number of numerical complex zero pairs 

AND Number of numerical real poles 

AND Number of numerical complex pole pairs 

AND Number of nonminimum phase numerical real zeros 

AND Number of nonminimum phase numerical complex zero pairs 

AND Number of unstable numerical real poles 

AND Number of unstable numerical complex pole pairs 

AND Inverse time constant of real zero #1 

AND Inverse time constant of real zero #2 

AND Inverse time constant of real zero #3 

AND Inverse time constant of real zero #4 

AND Inverse time constant of real zero #5 

AND Inverse time constant of real zero #6 

AND Damping ratio of complex zero pair #1 

AND Natural frequency of complex zero pair #1 

AND natural frequency of complex zero pair #2 

AND Damping ratio of complex zero pair #3 

I AND High frequency gain 

I AND Damping ratio of complex zero pair #2 

I TR-1228-1-11 172 
AND natural frequency of complex zero pair #3 

AND Damping ratio of complex zero pair #4 

AND natural frequency of complex zero pair #4 

AND Damping ratio of complex zero pair #5 

AND natural frequency of complex zero pair #5 

AND natural frequency of complex zero pair #6 

AND Inverse time constant of real pole #l 

AND Inverse time constant of real pole #3 

AND Inverse time constant of real pole #4 

AND Inverse time constant of real pole #5 

AND Inverse time constant of real pole #6 

AND Damping ratio of complex pole pair #1 

AND natural frequency of complex pole pair #1 

AND Damping ratio of complex pole pair #2 

AND natural frequency of complex pole pair #2 

AND Damping ratio of complex pole pair #3 

AND natural frequency of complex pole pair #3 

AND Damping ratio of complex pole pair W4 

AND natural frequency of complex pole pair #4 

AND Damping ratio of complex pole pair #5 

AND natural frequency of complex pole pair #5 

AND Damping ratio of complex pole pair #6 

AND natural frequency of complex pole pair #6 

AND Inverse time constant of bare airframe real pole #1 

AND Inverse time constant of bare airframe real pole #2 

AND Damping ratio of bare airframe complex pole pair #1 

AND Natural frequency of bare airframe complex pole pair #1 

8 AND Damping ratio of complex zero pair #6 

s AND Inverse time constant of real pole #2 

STRING Transfer function $$g filename 

AND St35 

AND St36 

AND St37 

................................................................ 

! 

! Parameter Initialization Statements 

! 

................................................................ 

! 

! Control Element Selectors 

THRESHOLD = 60 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

# 

I $ExHAUSTv. SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

TR-1228-1-11 173 
! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI. SHR" and combined with this knowledge base 

! during compilation. 

I 

$MULTI . SHR 

................................................................ 

! 

! Goal Outline 

1. Return to calling expert 

! 

! 

! Rules 

! 

................................................................. 

RULE for reading specified system transfer function into expert system 

! Activates program "TFCCLS" to convert specified system transfer function 

! (in Program CC ll$$ggl file) to LEVEL 5 format stored in file TFTRANS.PRM. 

! This file is then read into the knowledge base. 

St35 := "C:\STI\$$" ! Subdirectory containing files and macros below 

St36 := Transfer function $$g filename 

St37 := "C:\FCSDAT\TFTRANS.PRM" ! Transfer function file in LEVEL 5 format 

IF System model has been generated 

SEND St35 

SEND St36 

SEND St37 

THEN Specified system transfer function has been transmitted 

! File TFTRANS.PRM contains the transfer function in LEVEL5 format 

! 

AND READ C:\FCSDAT\TFTRANS.PRM I DATA Number of numerical real zeros 

DATA Number of numerical complex zero pairs 

I DATA Number of numerical real poles 

DATA Number of numerical complex pole pairs 

DATA Number of nonminimum phase numerical real zeros 

DATA Number of nonminimum phase numerical complex zero pairs 

DATA Number of unstable numerical real poles 

DATA Number of unstable numerical complex pole pairs 

DATA High frequency gain 

DATA Inverse time constant of real zero #1 

DATA Inverse time constant of real zero #2 

DATA Inverse time constant of real zero #3 

DATA Inverse time constant of real zero #4 

DATA Inverse time constant of real zero #5 

DATA Inverse time constant of real zero #6 

DATA Damping ratio of complex zero pair #1 

DATA natural frequency of complex zero pair #1 

I AND ACTIVATE C:\STI\TFCCL5.EXE 

I Zeros and poles are stored in order of increasing frequency 

174 TR-1228-1-11 
I 

DATA Damping ratio of complex zero pair #2 

DATA natural frequency of complex zero pair #2 

DATA Damping ratio of complex zero pair #3 

DATA natural frequency of complex zero pair #3 

DATA Damping ratio of complex zero pair #4 

DATA natural frequency of complex zero pair #4 

DATA Damping ratio of complex zero pair #5 

DATA natural frequency of complex zero pair #5 

DATA Damping ratio of complex zero pair #6 

DATA natural frequency of complex zero pair #6 

DATA Inverse time constant of real pole #1 

DATA Inverse time constant of real pole #2 

DATA Inverse time constant of real pole #3 

DATA Inverse time constant of real pole #4 

DATA Inverse time constant of real pole #5 

DATA Inverse time constant of real pole #6 

DATA Damping ratio of complex pole pair #1 

DATA natural frequency of complex pole pair #1 

DATA Damping ratio of complex pole pair #2 

DATA natural frequency of complex pole pair #2 

DATA Damping ratio of complex pole pair #3 

DATA natural frequency of complex pole pair #3 

DATA Damping ratio of complex pole pair #4 

DATA natural frequency of complex pole pair #4 

DATA Damping ratio of complex pole pair #5 

DATA natural frequency of complex pole pair #5 

DATA Damping ratio of complex pole pair #6 

DATA natural frequency of complex pole pair #6 

'AND DISPLAY TF data 

RULE for returning to calling expert 

IF Specified system transfer function has been transmitted 

AND Calling expert IS YAWDMPR expert 

THEN Return to calling expert 

AND CHAIN C:\FCSXPRT\YAWDMPR 

RULE for returning to calling expert 

IF Specified system transfer function has been transmitted 

AND Calling expert IS ROLLDMPR expert 

THEN Return to calling expert 

AND CHAIN C:\FCSXPRT\ROLLDMPR 

!=-- - 

! 

! Information Display Text 

DISPLAY TF data 

Number of real zeros - [Number of numerical real zeros] 

Number of complex zero pairs - [Number of numerical complex zero pairs] 

Number of real poles - [Number of numerical real poles] 

Number of complex poles - [Number of numerical complex pole pairs] 

Number of nonminimum phase real zeros - [Number of nonminimum phase numerical real zeros 

TR-1228-1-11 175 
Number of nonminimum phase complex zero - [Number of nonminimum phase numerical complex 

zero pairs] 

Number of unstble real poles - [Number of unstable numerical real poles] 

Number of unstable complex poles - [Number of unstable numerical complex pole pairs] 

High frequency gain - [High frequency gain] I 

Zeros : 

Real - [Inverse time constant of real zero #1] 

Real - [Inverse time constant of real zero #2] 

Real - [Inverse time constant of real zero #3] 

Real - [Inverse time constant of real zero #4] 

Real - [Inverse time constant of real zero #5] 

Real - [Inverse time constant of real zero #6] 

Damping ratio - [Damping ratio of complex zero pair #1] 

Frequency - [natural frequency of complex zero pair #1] 

Damping ratio - [Damping ratio of complex zero pair #2] 

Frequency - [natural frequency of complex zero pair #2] 

Damping ratio - [Damping ratio of complex zero pair #3] 

Frequency - [natural frequency of complex zero pair #3] 

Damping ratio - [Damping ratio of complex zero pair #4] 

Frequency - [natural frequency of complex zero pair #4] 

Damping ratio - [Damping ratio of complex zero pair #5] 

Frequency - [natural frequency of complex zero pair #5] 

Damping ratio - [Damping ratio of complex zero pair #6] 

Frequency - [natural frequency of complex zero pair #6] 

Poles : 

Real - [Inverse time constant of real pole #l] 

Real - [Inverse time constant of real pole #2] 

Real - [Inverse time constant of real pole #3] 

Real - [Inverse time constant of real pole #4] 

Real - [Inverse time constant of real pole #5] 

Real - [Inverse time constant of real pole #6] 

Damping ratio - [Damping ratio of complex pole pair #1] 

Frequency - [natural frequency of complex pole pair #1] 

Damping ratio - [Damping ratio of complex pole pair #2] 

Frequnecy - [natural frequency of complex pole pair #2] 

Damping ratio - [Damping ratio of complex pole pair #3] 

Frequency - [natural frequency of complex pole pair #3] 

Damping ratio - [Damping ratio of complex pole pair #4] 

Frequency - [natural frequency of complex pole pair #4] 

Damping ratio - [Damping ratio of complex pole pair #5] 

Frequency - [natural frequency of complex pole pair #5] 

Damping ratio - [Damping ratio of complex pole pair #6] 

Frequency - [natural frequency of complex pole pair #6] 

! 

END 

TR-1228-1-11 176 
ROOTlD.PRL 

TR-1228-1-II 177 
! "ROOTID. PRL" 

! 

! SYSTEMS TECHNOLOGY, INC Hawthorne, CA 

TITLE Augmented Aircraft Pole and Zero Identification (ROOTID) DISPLAY 

This expert manages the physical identification of poles 

and zeros of an aircraft with complete or partial augementation. 

To continue, press F3 

! 

! 

! called. 

The ROOTID expert acts on the current system transfer function in FCX. 

The TFEXT knowledge base must be exercised properly before ROOTID is 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type.Declarations 

! 

................................................................ 

! 

! Parameter Initialization Statements 

! 

................................................................ 

! 

! Control Element Selectors 

~ 

THRESHOLD - 60 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV. SHR 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! 

! The "MULTI" Declaration of multiattributed objects is stored in the 

! "include" file named "MULTI. SHR" and combined with this knowledge base 

! during compilation. 

TR-1228-1-11 178 

I 
$MULTI . SHR 

I ................................................................ 

! 

! Goal Outline 

t 1. Return to calling expert 

! 

! 

I ! Rules 

! 

................................................................. 

! Rules for identifying poles 

RULE for poles and zeros of open loop aircraft 

IF 

AND Current architecture IS RD&YD 

AND Roll damper loop connection IS open 

AND Yaw damper loop connection IS open 

AND Transfer function $$g filename - "G26032" 

THEN System poles are identified 

AND Wrs := natural frequency of complex zero pair #1 

AND DISPLAY Pole summary 0 

Specified system transfer function has been transmitted 

RULE for poles and zeros of open loop aircraft 

IF 

AND Current architecture IS RD&YD 

AND Roll damper loop connection IS open 

AND Yaw damper loop connection IS open 

AND Transfer function $$g filename - "G26052" 

THEN System poles are identified 

AND DISPLAY Pole summary 0 

Specified system transfer function has been transmitted 

RULE for poles with yaw damper only 

IF 

AND Current architecture IS RD&YD 

AND Roll damper loop connection IS open 

AND Yaw damper loop connection IS closed 

THEN System poles are identified 

AND ITS' :- Inverse time constant of real pole #1 

AND ITr' := Inverse time constant of real pole #2 

AND Zd' :- Damping ratio of complex pole pair #1 

AND Wd' := natural frequency of complex pole pair #1 

AND DISPLAY Pole summary 1 

Specified system transfer function has been transmitted 

e 

L RULE for poles with yaw and roll damper 

IF Specified system transfer function has been transmitted 

AND Current architecture IS RD&YD 

AND Roll damper loop connection IS closed 

TR-1228-1-11 179 
AND Yaw damper loop connection IS closed 

THEN System poles are identified 

AND ITS" :- Inverse time constant of real pole #1 

AND ITr" :- Inverse time constant of real pole #2 

AND Zd" :- Damping ratio of complex pole pair #1 

AND Wd" :- natural frequency of complex pole pair #1 

AND DISPLAY Pole summary 2 

RULE for returning to calling expert 

IF System poles are identified 

AND Calling expert IS YAWDMPR expert 

THEN Return to calling expert 

AND CHAIN C:\FCSXPRT\YAWDMPR 

RULE for returning to calling expert 

IF System poles are identified 

AND Calling expert IS ROLLDMPR expert 

THEN Return to calling expert 

AND CHAIN C:\FCSXPRT\ROLLDMPR 

! 

! Information Display Text 

DISPLAY Pole summary 0 

All FCS loops are OPEN 

Spiral mode inverse time constant - [ITS] radlsec 

Roll subsidence mode inverse time constant - [ITr] radlsec 

Dutch roll undamped natural frequency - [Wd] radlsec 

rfldr complex zero frequency - [Wrs] radlsec 

Dutch roll damping ratio - [Zdl 

To continue, press F2 

DISPLAY Pole summary 1 

1 loop is closed 

Spiral mode inverse time constant - [ITS'] radlsec 

Roll subsidence mode inverse time constant - [ITr'] radlsec 

Dutch roll damping ratio - [Zd'] 

Dutch roll undamped natural frequency = [Wd'] radlsec 

To continue, press F2 

DISPLAY Pole summary 2 

2 loops are closed 

180 TR-1228-1-11 
Spiral mode inverse time constant - [ITS"] radlsec 

Roll subsidence mode inverse time constant - [ITr"] radlsec 

Dutch roll damping ratio * [Zd"] 

Dutch roll undamped natural frequency - [Wd"] radlsec 

To continue, press F2 

! 

END 

TR-1228-1-11 181 
ASSESS.PRL 

TR-1228-1-11 182 
! "ASSESS. PRL" 

! 

TITLE AIRCRAFT DYNAMICS ASSESSMENT (ASSESS) DISPLAY 

t This expert assists in the assessment of the current system -- aircraft 

plus the loops presently designed for the current architecture -- with 

respect to appropriate design requirements. 

To continue, PRESS F3 

............................................................... 

! 

! Shared Facts Declarations 

! 

! The Shared Facts Declaration is stored in the "include" file named 

! "SHAREFCT.SHR" and combined with this knowledge base during compilation. 

! 

$SHAREFCT.SHR 

! 

................................................................ 

! 

! Data Type Declarations 

! 

................................................................ 

! 

! Parameter Initialization Statements 

! 

................................................................ 

! 

! Control Element Selectors 

THRESHOLD * 100 

CONFIDENCE OFF 

GOALSELECT ON 

UNKNOWN CONTINUE 

$EXHAUSTV. SHR 

t 

..................................................................... 

! 

! Multiattributed Objects Declarations 

! The llMULTI1l Declaration of multiattributed objects is stored in the 

! 'linclude" file named "MULTI . SHR" and combined with this knowledge base 

! during compilation. 

I 

TR-1228-1-11 1 a3 
$MULTI . SHR 

................................................................ 

! 

! Goal Outline 

1. Dynamics variables are set 

1.1 Requirement comparison is complete 

! 

! Rules 

! 

! ................................................................ 

! 

! 

! 

RULE for open loop aircraft 

IF Yaw damper loop connection IS open 

AND Roll damper loop connection IS open 

THEN Dynamics variables are set 

AND spiral mode inverse time constant :- ITS 

AND roll subsidence mode inverse time constant := ITr 

AND Dutch roll damping ratio := Zd 

AND Dutch roll natural frequency :- Wd 

Rules for setting dynamics variables 

RULE for only yaw damper closed 

IF Yaw damper-loop connection IS closed 

AND Roll damper loop connection IS open 

THEN Dynamics variables are set 

AND spiral mode inverse time constant :- ITS' 

AND roll subsidence mode inverse time constant := ITr' 

AND Dutch roll damping ratio := Zd' 

AND Dutch roll natural frequency :- Wd' 

RULE for yaw damper and roll damper closed 

IF Yaw damper loop connection IS closed 

THEN Dynamics variables are set 

AND spiral mode inverse time constant := ITS'' 

AND roll subsidence mode inverse time constant :- ITr" 

AND Dutch roll damping ratio := Zd" 

AND Dutch roll natural frequency := Wd" 

, AND Roll damper loop connection IS closed 

~ ! ................................................................. 

! 

! Rules for assessing requirements 

RULE for assessing dutch roll damping ratio 

IF dutch roll damping ratio >- dutch roll damping ratio spec 

THEN dutch roll damping ratio assessment IS adequate I 

TR-1228-1-11 184 
AND dutch roll damping ratio has been assessed 

ELSE dutch roll damping ratio assessment IS too low 

AND dutch roll damping ratio has been assessed 

RULE for assessing dutch roll mode 

IF dutch roll damping ratio assessment IS adequate 

! AND dutch roll natural frequency IS adequate 

THEN dutch roll mode dynamics are adequate 

AND dutch roll mode has been compared with the requirements 

AND DISPLAY Dutch roll summary 

ELSE NOT dutch roll mode dynamics are adequate 

AND dutch roll mode has been compared with the requirements 

AND DISPLAY Dutch roll summary 

4 

RULE for assessing 

IF roll subsidence mode inverse time constant >- : 

l/(Roll subsidence mode time constant spec) 

THEN roll subsidence mode time constant assessment IS adequate 

AND roll mode time constant has been assessed 

ELSE roll subsidence mode time constant assessment IS too high 

AND roll mode time constant has been assessed 

roll subsidence mode 

RULE for assessing roll subsidence mode 

IF roll subsidence mode time constant assessment IS adequate 

THEN roll subsidence mode dynamics are adequate 

AND roll subsidence mode has been assessed 

AND DISPLAY Roll subsidence summary 

ELSE NOT roll subsideme mode dynamics are adequate 

AND roll subsidence mode has been assessed 

AND DISPLAY Roll subsidence summary 

RULE for assessing modal characteristics 

IF dutch roll mode dynamics are adequate 

AND roll subsidence mode dynamics are adequate 

!. AND spiral mode dynamics are adequate 

THEN modal dynamics are adequate 

AND system has been compared with the requirements 

AND DISPLAY modal dynamics summary 

ELSE NOT modal dynamics are adequate 

AND system has been compared with the requirements 

AND DISPLAY modal dynamics summary 

.................................................................. 

! 

! Rules for determining the next activity 

RULE for determining if requirement comparison has been completed 

IF system has been compared with the requirements 

AND Current loop IS yaw damper 

THEN requirement comparison is complete 

! 

AND FORGET Yaw damper loop assessment 

i 

AND DISPLAY requirement comparison results 

TR-1228-1-11 185 
AND CHAIN C:\FCSXPRT\YAWDMPR 

RULE for determining if requirement comparison has been completed 

IF system has been compared with the requirements 

AND Current loop IS roll damper 

THEN requirement comparison is complete 

! 

AND FORGET Roll damper loop assessment 

AND CHAIN C:\FCSXPRT\ROLLDMPR 

AND DISPLAY requirement comparison results 

L 

! 

! 

! Information Display Text 

! 

DISPLAY Dutch roll summary 

Comparison of the current system with the requirements indicates that the 

Dutch roll damping ratio is [dutch roll damping ratio assessment] 

Thus it is [dutch roll mode dynamics are adequate] that the dutch roll mode dynamics are 

adequate. 

To continue, press F2 

DISPLAY Roll subsidence summary 

Comparison of the current system with the requirements indicates that the 

Roll subsidence mode time constant is [roll subsidence mode time constant 

assessment] 

Thus it is [roll subsidence mode dynamics are adequate] that the roll subsidence mode 

dynamics are adequate. 

To continue, press F2 

DISPLAY modal dynamics summary 

Comparison of the current system with the requirements indicates that 

it is [modal dynamics are adequate] that the modal dynamics are adequate 

To continue, press F2 

END t 

TR-1228-1-11 186 
t 

1. Report No. 2. Government Accession No. 

NASA CR-181726 

4. Title and Subtitle 

Advanced Piloted Aircraft Flight Control System 

Report Documentation Page 

3. Recipient's Catalog No. 

5. Report Date 

October 1988 

Expert System 

7. AuthorM 

Design Methodology 

Volume 11: The FCX Flight Control Design 

8. Performing Organization Report No. 

I 

13766 South Hawthorne Boulevard 

Hawthorne, CA 90250-7083 

12. Sponsoring Agency Name and Address 

6. Performing Organization Code 

NAS1-17987 

13. Type of Report and Period Covered 

Contractor Report 

17. Key Words (Suggested by Authork)) 

Artificial intelligence (AI) 

Expert systems 

Flight control system design 

Knowledge-based design 

Natural language interface 

Thomas T. Myers and kane T. McRuer 

18. Distribution Statement 

Unclassified - Unlimited 

Subject Category 08 

STT TR-1228-1 

10. Work Unit No. 

19. Security Classif. (of this report) 

Unclassified 

505-66-0 1-02 9. Performing Organization Name and Address 

11. Contract or Grant No. 

Systems Technology, Inc. 

20. Security Classif. (of this page) 21. No. of pages 22. Price 

Unclassified 190 

National Aeronautics and Space Administration 

Langley Research Center 

Hampton, VA 23665-5225 I 14. Sponsoring hgency Code 

I 

15. Supplementary Notes 

Langley Technical Monitor: Jarrell R. Elliott 

SBIR Phase I1 Final Report 

16. Abstract 

This report presents and illustrates the development of a comprehensive and 

eclectic methodology for conceptual and preliminary design of flight control 

systems. The methodology is focused on the design stages starting with the 

layout of system requirements and ending when some viable competing system 

architectures (feedback control structures) are defined. The approach is 

centered on the human pilot and the aircraft as both the sources of, and the 

keys to the solution of, many flight control problems. The methodology relies 

heavily on computational procedures which are highly interactive with the design 

engineer. To maximize effectiveness, these techniques, as selected and modified 

to be used together in the methodology, form a cadre of computational tools 

specifically tailored for integrated flight control system preliminary design 

purposes. The computer aids are all based on IBM PC compatible machines and 

most are now commercially available. 

available and useful as possible instead of simply another isolated approach. 

This helps make the methodology as broadly 

,o 'a 76 G': .~ -