Abstract:
An integration test station for aircraft is provided in which the system is operable with multiple aircraft configurations. The integration test station permits aircraft component designs to be tested and verified in a simulated environment representing integration of the component into the aircraft.

Description:
FIELD OF THE INVENTION 
     This invention pertains to test systems, in general, and to an integration test system for aircraft, in particular. 
     BACKGROUND OF THE INVENTION 
     An aircraft is an assembly of numerous interacting mechanical and electrical components that need to function properly for the aircraft to operate safely. An important step in the manufacture of aircraft is the testing of each component in order to verify the design of the component. The operability of a newly designed component when integrated into the environment of an aircraft is essential to a determination of the viability of the design. Testing of this kind is referred to as “integration” testing. Almost all aircraft components are subjected to integration testing prior to installation in the aircraft. To perform such testing, it is important that the component is tested in an environment that simulates the conditions that will occur during flight. This testing requires that the component receives stimuli which are representative of the stimuli that would be received during actual flight conditions and that the component responds to the stimuli in a predictable and correct fashion. 
     One method of testing newly designed components is to rely either on flight testing of the aircraft or on system testing when the aircraft is on the ground. Flight testing, as the name implies, involves flying the aircraft in order to ensure that the various components operate properly with each other and that the design of a new component or the new design of an existing component operates as expected. Flight testing, while useful, has limitations. In flight testing it is difficult, if not impossible, to expose an aircraft to all conditions to which it might be exposed in order to observe how the component will respond. For example, environmental conditions such as sudden cross winds cannot be developed on command. Also, complex aircraft, such as modem commercial airliners, comprise a large number of components that are assembled into numerous systems. The complexity increases even more with modem military aircraft. The components and systems must be subjected to numerous test procedures in order to ensure that the design functions properly. It is neither an efficient use of time nor an efficient use of resources to repeatedly flight test an aircraft solely to ascertain whether a specific assembly of components are performing as anticipated. In addition, a number of test procedures involve verifying or determining the operation of the aircraft under potentially threatening or extreme conditions such as high wind, low altitude flight conditions. Testing an aircraft under such conditions can jeopardize the safety of both the aircraft and the flight crew. 
     The alternative to flight testing an aircraft is ground testing utilizing integration test stations. Integration test stations are distinct and separate from test stations that are utilized for testing during manufacture or subsequent to manufacture for maintenance. One key distinction is that integration test stations are used to verify design and operation of the component being tested in a simulated operational environment, whereas other test equipment is used for verification of operability on equipment or components after validation. 
     All prior integration testing systems are aircraft specific. In many instances the testing systems are even aircraft version specific. It is highly desirable that an integration test system be available to be operable with multiple aircraft and to be easily changeable from one aircraft to another. 
     SUMMARY OF THE INVENTION 
     In accordance with the principles of the invention an integration test station is provided that may be utilized for multiple aircraft and/or aircraft versions. An integration test station in accordance with the invention has the capability to perform acceptance testing and permits the user to “break into the system” to troubleshoot design anomalies as well as perform design performance tests. The integration test system supports an integration capability into which other real systems can be easily connected or simulated in an endless variety of possible combinations. This capability allows system developers to verify design operation and interaction between subsystem elements. 
     In a system in accordance with the invention, simulation and monitoring functions are modularized. Circuit cards and cables are reused from configuration to configuration. Control and monitoring aspects of simulation and monitoring functions are supported with a power and communications core. Signal paths from simulation cards are routed through jumper connectors/plugs that permit connectivity to real aircraft components. 
     Software is provided in a host computer that contains a core operating system that in turn calls down different simulation or monitor configurations to match the specific system under test. Configurations are user selectable during system power up. 
     Simulation and monitor modules are connectorized with connectors utilized to map to specific system wiring. The connectors can be easily changed to switch between different systems. 
     In accordance with the principles of the invention, an integration test station includes software that is reconfigured for each new configuration for which testing is to be performed. Further in accordance with the principles of the invention, an integration test station includes a cable arrangement that permits connection to a large number of different aircraft components and permits validation of component designs. The cable arrangement is connectorized to a “personality module” that maps wiring by different functions to various circuit boards. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention will be better understood from a reading of the following detailed description in conjunction with the several figures of the drawing in which like reference numerals are used to designate like elements and, in which: 
     FIG. 1 illustrates in block diagram form an integration test station in accordance with the invention; 
     FIG. 1A illustrates a portion of the station of FIG. 1 in greater detail; 
     FIG. 2 depicts the software architecture of a test system formed in accordance with the invention; 
     FIG. 3 illustrates a portion of the integration test station of FIG. 1 in greater detail; and 
     FIG. 4 is a connection diagram for the portion shown in FIG.  3 . 
    
    
     DETAILED DESCRIPTION 
     Integration test stations are distinct from acceptance test equipment that is utilized in a production environment. There are key points that are important to understanding the distinctions. Although an integration test station has the capability to perform all acceptance test functions in a production environment, it also permits the user to “break into the system” and troubleshoot design anomalies as well as to perform design performance tests. Additionally, an integration test station should allow for verification of design operation and interaction between subsystem elements. 
     FIG.  1  and FIG. 1A depict an aircraft integration test station  20  formed in accordance with the principles of the invention connected to an aircraft unit under test (UUT)  22 . System  20  includes a central processing unit  90  which is coupled to a workstation  96 . As shown in FIG. 2, central processing unit  90  is coupled to workstation  96  via an Ethernet hardware interface  93 . Workstation  96  is a commercially available workstation of a type that conforms to a UDP/IP Ethernet Protocol. From the workstation  96 , a user of system  20  can control and direct testing of UUT  22 . System  20  includes commercially available standard instruments  132  as well as non-programmable simulation or simulator cards  133  and programmable simulation or simulator cards  134 - 136 . The instruments  132  and the non-programmable and programmable simulator cards  133 - 136  generate stimuli normally received by the components of the particular aircraft in which the UUT  22  is designed for installation. Instruments  132  as well as the non-programmable and programmable simulator cards  133 - 136  are coupled to central processing unit  90  via a high speed backplane or bus  95 . Some of commercial instruments  132  are used to monitor the response of the components of the aircraft and other ones of commercial instruments  132  generate stimuli. Central processing unit  90  contains a real time operating system that contains an Ethernet driver capable of parsing a test station standard message into commands for simulation control and monitoring. A memory or software configuration storage element  91  is coupled to central processing unit  90  via common high speed backplane or bus  95 . The common high speed backplane or bus  95  is of a type known in the art and is referred to as a VME bus or backplane. As shown in FIG. 2, software configuration storage element  91  includes actuation and sensor models  155  and startup/configuration files  156 . 
     Prior to power up of UUT  22 , the system  20  user will connect an Interface Test Adapter (ITA)  23  selected for UUT  22 . Installation of ITA  23  and UUT  22  comprise the hardware aspects of configuring integration test station  20  for a specific aircraft. Subsequently, the appropriate software is loaded using the software configuration storage element  91 . When central processing unit  90  is operated to run integration tests on a specific component  22 , the system user will enter information to the central processing unit  90  via workstation  96  which specifies what aircraft system is to be tested. In the embodiment of the invention shown, the system user specifies the system to be tested during power up. All configuration information and simulation models are stored in the software configuration storage element  91 . Central processing unit  90  loads appropriate models and communication data as required for each specific system application from software configuration storage element  91 . This is accomplished during power up by the system user specifying what system is to be tested. After power up, simulator cards  133 - 136  and commercial standard instruments  132  autonomously provide simulation conditions to UUT  22 . Central processing unit  90  operates as a communications control and conduit that receives formatted messages and directs the appropriate commands to the simulator cards  133 - 136  and instruments  132 . Central processing unit  90  also reads appropriate monitor signals from the instruments  132  as well as from those of simulator cards  133 - 136  which provide monitoring functions. In addition, a high speed real time interface  14  is coupled to high speed backplane or bus  95 . High speed real time interface  14  is coupled via a high speed data bus such as an Ethernet bus  97  to external aircraft simulation models  92 . Real time parameters can be read either via high speed real time interface  14  or via central processing unit  90  to support aircraft dynamics to the aircraft component  22 . The real time parameters are used to control the operation of instruments  132  and simulator cards  133 - 136  and also include data relevant to expected response data obtained from the UUT  22 . When the stimuli are applied to UUT  22 , instruments  132  and certain ones of the simulator cards  133 - 136  monitor responses from component  22 . Central processing unit  90  analyzes the output signals from UUT  22  and from simulated actuation of any cockpit controls. Instruments  132  and simulator cards  133 - 136  are instructed by central processing unit  90  to produce an updated set of stimuli. All simulation and monitoring functions are integrated onto common high speed backplane or bus  95  which can accommodate any combination of simulations or monitoring functions to suit the needs of the system test. Central processing unit  90  integrates all simulations together to provide the user of system  20  control of all types of simulation from one workstation using a similar graphical interface that is used across a multitude of simulations. 
     FIG. 2 illustrates in block form the software architecture utilized in the integration test station  20  (FIG.  1 ). Central processing unit  90  includes a real time operating system  150  that includes an Ethernet interface. The Ethernet interface conforms to a UDP/IP Ethernet protocol. Operating systems of this type are commercially available. Central processing unit  90  and the software executed at central processing unit  90  acts as a central point where all information is passed between internal simulations at integration test station  20  and the outside world. An external host/aircraft simulation model  170  connected to integration test station  20  can control simulations if the software on the external host/aircraft simulation model  170  is programmed to communicate with integration test station  20  using the integration test station  20  protocol. External host/aircraft simulation model  170  includes user supplied aircraft models  171 . After start up and initialization of the simulations, central processing unit  90  executes tasks  151  through  154 . Task  151  provides an external user interface whereby a user of the system can designate operational testing. Task  152  provides for automatic testing of UUT  22 . Inter-simulation data sharing package  153  provides for the intercommunication of simulator data among the instruments  132  and simulation cards  133 - 136 . High speed shared memory data transfer task  154  permits the communication between the various units connected to the high speed backplane or bus  95 . 
     Workstation  96  operates in tandem with the external host/aircraft simulation model  170  allowing the system operator at a workstation  96  to inject failures into parts of the simulated aircraft while it is in flight to evaluate the responses of UUT  22  with the pilot in the loop to evaluate handling qualities in different failure situations. Injection of failures can be accomplished using a manual control graphical interface  161  which operates in conjunction with user/test specific configuration files  162 . Automated testing capability provided by test scripts  163  permits integration test station  20  to test a system&#39;s performance before going to a simulation environment. This validation is to prove that the system matches the design criteria for the aircraft. Configuration files  162  are used to configure the work station for the particular test to be performed. Configuration files  162  contain the names and data signals specific to UUT  22  along with memory mapping to simulations so that the user of integration test station  20  only has to understand UUT  22  and not be concerned with how integration test station  20  operates. When a different UUT  22  is under test, appropriate configuration files are reloaded for that application and the user for that UUT  22  can use the names for that specific UUT  22 . Integration test station  20  initializes all control variable names to accommodate the user and eliminates the need for extensive training on the use of the integration test station  20 . When integration test station  20  is started up, the configuration files are used to assemble system tables and maps to the specified system being subjected to testing. Test scripts  163  are use to edit files by setting sequences and exercising the system as an open loop system. This permits external testing of the aircraft system and UUT  22  in a static environment to verify the design of UUT  22 . 
     In prior systems used for integration testing of a component, the system  20  is uniquely configured for the particular aircraft which contains the component to be tested. In accordance with the present invention, the system  20  automatically configures itself for one of a plurality of aircraft. 
     In the test integration system of the present invention, simulation and monitoring functions are modularized. FIG. 3 illustrates the connections of a single simulator card to the UUT  22 . By way of example, the simulator card shown in FIG. 3 is simulator card  133 , but can be any of the simulator cards shown in FIG.  1 . Simulator card  133  has  133   k  that allow simulator card  133  to be inserted into the high speed backplane or bus  95  identified in FIG.  1 . Simulator card  133  has a connector  133   m  which mates to a connectorized cable  133   a . Cable  133   a  splits into a “T” with one branch of the “T” running to a real aircraft interface panel  141 . A connector on the real aircraft interface panel  141  has a connector  133   b . A jumper connector  133   c  is connected to connector  133   b . Jumper connector  133   c  is used to provide a jumpered connection between simulator card  133  and UUT  22 . If it is desired to connect another component such as a sensor or real aircraft component (FIG. 1)  72  to UUT  22 , jumper connector  133   c  is removed and real aircraft component  72  is connected in by using connectorized cable  72   a . The other branch of the “T” of cable  133   a  goes to a connector  133   d  which connects to interface test adapter card  133   e . Interface test adapter card  132   e  is used to map the pins of the connector  133   d  so that the aircraft specific wiring is correctly mapped to a standard cable layout. A cable  133   g  extends to UUT  22 . UUT  22  is disposed in a holding fixture  400 . 
     FIG. 4 illustrates the connection path for the portion of the integration test station shown in FIG.  3 . The connection path illustrates the connection between simulator card  133  via connector  133   c  to ITA  133   e  and to UUT  22 . 
     Turning back to FIGS. 1 and 1A, the multiple connections of the commercial standard instruments  132  and simulator cards  133 - 136  is shown. Simulator cards  133 - 136  are coupled to central processing unit  90  via bus  95 . The simulator cards  133 - 136  are reused from aircraft configuration to aircraft configuration and each represents a specific function that may be used from system to system. 
     Each simulator card  133 - 136  is associated with a particular function. Each simulator card  133 - 136  simulates one or two actuators or a sensor. Each simulator card  133 - 136  simulates analog or digital signals as appropriate. Each simulator card  133 - 136  and commercial standard instruments  132  has a cable connector. A connectorized cable  132   a - 136   a  is plugged into the respective connector. Each cable  132   a - 136   a  runs to a “T” with one branch of the “T” going to a real aircraft interface panel  141 . The real aircraft interface panel  141  including connectors  132   b - 136   b . Jumper connectors  132   c - 136   c  are useable to connect to connectors  132   b - 136   b . Normally, signals are jumpered from the component  22  being tested to simulator cards  133 - 136  and instrument  132 . If it is desired to hook up another component such as a sensor or real aircraft component  72   a  into any of the cables  132   a - 136   a  the corresponding jumper plug such as jumper plug  136   c  may be removed and a real aircraft component  72  is coupled in by a cable  72   a . The other branch of the “T” of each cable  132   a - 136   a  goes to a connectorized interface test adapter of a type known in the art and made generally available by the Virginia Panel Corp. of Waynesboro, Va. This type of interface test adapter is known as a Virginia Panel Receiver. In the illustrative embodiment of the invention, the Virginia Panel Receiver  300  is of a type having fifty connectors arranged into two rows of connectors. Each connector  132   d - 136   d  has 96 pins. The connections to the Virginia Panel Receiver connector are arranged in accordance with a standard layout. Interface test adapter cards (ITA)  132   e - 136   e  connected to each connector  132   d - 136   d  are used as personality modules to map the pins of the respective connectors  132   d - 136   d  so that the aircraft specific wiring is correctly mapped to a standard layout. Each Interface Test Adapter card  132   e - 136   e , includes a load card  132   f - 136   f  which simulates different loads corresponding to the aircraft specific elements that UUT  22  would be coupled to. Each Interface Test Adapter card  132   e - 136   e , is removable and is wired for each specific aircraft. Cables  132   g - 136   g  extend to UUT  22  under test. UUT  22  sits on holding fixture  400 . Holding fixture  400  is specific to UUT  22 . Holding fixture  400  is specific to the particular aircraft and serves to connect UUT  22  under test to appropriate mechanical simulations  401  such as pneumatic sources, cooling sources, and other mechanical connections all of which may be coupled to central processing unit  90 . The use of holding fixtures is known in the testing arts, and as those skilled in the art will understand, the holding fixture is program specific. Particular details of holding fixtures do not form part of the present invention. 
     With the arrangement of the present invention, multiple aircraft platforms are easily supported. Software may be reconfigured for each new system, autonomous hardware modules may be added or deleted as required to system interfaces, and the cabling is reconfigurable. Simulation signals from a core of simulations are provided in a standardized layout on a receiver panel. Aircraft specific wiring is accommodated by mapping in the Interface Test Adapter. Loads are contained in the ITA and therefore changing of the ITA changes the loads for the UUT. Thus program specific changes are accommodated by changing the ITAs, and by changing the cable between the ITA and the UUT and the holding fixture. Thus the integration test station of the present invention provides for easily reconfigurable cabling. With the integration test station of the present invention, if a new interface is developed, the test station can easily be utilized by providing new simulator cards. Each simulator card gets its own cable and connector. The cable is connected to the Virginia Panel Receiver  300  where an ITA provides mapping to the new simulation. If it is desired to upgrade the simulation and testing computers, an upgrade is easily accomplished by replacing only the circuit card. Furthermore, as those skilled in the art will readily appreciate, although the invention has been described in terms of testing of units or components adapted for inclusion on aircraft, the integration test station may be used for other vehicular testing as well including land, sea, air and space craft whether manned or unmanned 
     Although the invention has been described in terms of specific embodiments, those skilled in the art will appreciate that various changes, modifications and variations may be made to the embodiments without departing from the spirit or scope of the invention. It is intended that the invention not be limited by the embodiments shown but that the invention be limited in scope only by the claims appended hereto and that the claims encompass all such changes, modifications, and variations as well.