bluuebunny/crossref_metadata_2025 huggingface dataset:
STABILITY AND H∞ DISTURBANCE ATTENUATION ANALYSIS FOR LTI CONTROL SYSTEMS WITH CONTROLLER FAILURES
Authors: Zhai Guisheng , Chen Xinkai , Takai Shigemasa , Yasuda Kazunori
Published: September 2010

In this paper, we analyze stability and H∞ disturbance attenuation properties for linear time‐invariant (LTI) systems controlled by a pre‐designed dynamical output feedback controller which fails from time to time due to physical or purposeful reasons. Our aim is to find conditions concerning the controller failure time, under which the system's stability and H∞ disturbance attenuation properties are preserved to a desired level. For stability, by using a piecewise Lyapunov function, we show that if the unavailability rate of the controller is smaller than a specified constant and the average time interval between controller failures (ATBCF) is large enough, then the global exponential stability of the system is guaranteed. For H∞ disturbance attenuation, also by using a piecewise Lyapunov function, we show that if the unavailability rate of the controller is smaller than a specified constant, then a system with an ATBCF achieves a reasonable weighted H∞ disturbance attenuation level, and the weighted H∞ disturbance attenuation approaches normal H∞ disturbance attenuation when the ATBCF is sufficiently large.
STABILITY CRITERIA FOR A CLASS OF NEUTRAL SYSTEMS VIA THE LMI APPROACH
Authors: Lien Chang‐Hua , Chen Jenq‐Der
Published: September 2010

In this paper, the asymptotic stability for a class of neutral systems with multiple discrete and distributed time delays is investigated. The Lyapunov stability theory is applied to guarantee the stability of the systems. The linear matrix inequality (LMI) approach is used to improve our results. By means of some mathematical analysis, the presented conditions are proved to be less conservative and flexible than some recent reports. A numerical example is given to illustrate the use of our results.
INPUT‐STATE LINEARIZATION OF A ROTARY INVERTED PENDULUM
Authors: Chen Chih‐Keng , Lin Chih‐Jer , Yao Liang‐Chun
Published: September 2010

The aim of this paper is to design a nonlinear controller for the rotary inverted pendulum system using the input‐state linearization method. The system is linearized, and the conditions necessary for the system to be linearizable are discussed. The range of the equilibriums of the system is also investigated. Further, after the system is linearized, the linear servo controllers are designed based on the pole‐placement scheme to control the output tracking problem. The performance of the controller is studied with different system parameters. The computer simulations demonstrate that the controller can effectively track the reference inputs.
ROBUST TWO‐DEGREE‐OF‐FREEDOM CONTROL OF AN ATOMIC FORCE MICROSCOPE
Authors: Schitter G. , Stemmer A. , Allgöwer F.
Published: September 2010

The performance of an atomic force microscope (AFM) is improved substantially by utilizing modern model‐based control methods in comparison to a standard proportional‐integral (PI) controlled AFM system. We present the design and implementation of a two‐degree‐of‐freedom (2DOF)‐controller to accomplish topography measurements at high scan‐rates with reduced measurement error. An H∞‐controller operates the AFM system in a closed loop while a model‐based feedforward controller tracks the scanner to the last recorded scan‐line. Experimental results compare the actual performance of the standard PI‐controlled AFM and the 2DOF controlled system. The new controller reduces the control error considerably and enables imaging at higher speeds and at weaker tip‐sample interaction forces.
CONTROL ISSUES IN HIGH‐SPEED AFM FOR BIOLOGICAL APPLICATIONS: COLLAGEN IMAGING EXAMPLE
Authors: Zou Q. , Leang K. K. , Sadoun E. , Reed M. J. , Devasia S.
Published: September 2010

This article considers the precision positioning problem associated with high‐speed operation of the Atomic Force Microscope (AFM), and presents an inversion‐based control approach to achieve precision positioning. Although AFMs have high (nanoscale) spatial resolution, a problem with current AFM systems is that they have low temporal resolution, i.e., AFM imaging is slow. In particular, current AFM imaging cannot be used to provide three‐dimensional, time‐lapse images of fast processes when imaging relatively‐large, soft samples. For instance, current AFM imaging of living cells takes 1–2 minutes (per image frame) — such imaging speeds are too slow to study rapid biological processes that occur in seconds, e.g., to investigate the rapid movement of cells or the fast dehydration and denaturation of collagen. This inability, to rapidly image fast biological processes, motivates our current research to increase the operating speed of the AFM. We apply an inversion‐based feedback/feedforward control approach to overcome positioning problems that limit the operating speed of current AFM systems. The efficacy of the method, to achieve high‐speed AFM operation, is experimentally evaluated by applying it to image collagen samples.
MARKOV DECISION PROCESSES WITH UNCERTAIN TRANSITION RATES: SENSITIVITY AND MAX HYPHEN MIN CONTROL
Authors: Kalyanasundaram Suresh , Chong Edwin K. P. , Shroff Ness B.
Published: September 2010

Solution techniques for Markov decision problems rely on exact knowledge of the transition rates, which may be difficult or impossible to obtain. In this paper, we consider Markov decision problems with uncertain transition rates represented as compact sets. We first consider the problem of sensitivity analysis where the aim is to quantify the range of uncertainty of the average per‐unit‐time reward given the range of uncertainty of the transition rates. We then develop solution techniques for the problem of obtaining the max‐min optimal policy, which maximizes the worst‐case average per‐unit‐time reward. In each of these problems, we distinguish between systems that can have their transition rates chosen independently and those where the transition rates depend on each other. Our solution techniques are applicable to Markov decision processes with fixed but unknown transition rates and to those with time‐varying transition rates.
MARKING ESTIMATION OF PETRI NETS WITH PAIRS OF NONDETERMINISTIC TRANSITIONS
Authors: Giua Alessandro , Seatzu Carla , Júlvez Jorge
Published: September 2010

We present a technique for estimating the marking of a Petri net based on the observation of transition labels. In particular, the main contribution of the paper consists in deriving a methodology that can handle the case of nondeterministic transitions, i.e., transitions that share the same label. Under some technical assumptions, the set of markings consistent with an observation can be represented by a linear system with a fixed structure that does not depend on the length of the observed word.
VS‐CONTROL WITH TIME‐VARYING SLIDING SECTOR — DESIGN AND APPLICATION TO PENDULUM —
Authors: Suzuki Satoshi , Pan Yaodong , Furuta Katsuhisa , Hatakeyama Shoshiro
Published: September 2010

In general, a Variable Structure (VS) system is designed with a sliding mode. Recently a sliding sector, designed by an algebraic Riccati equation, has been proposed to replace the sliding mode for chattering‐free VS controllers. In this paper we extend the design algorithm for the sliding sector to a time‐varying sliding sector. The time‐varying sliding sector is defined by functions dependent on both state and time, hence time‐varying uncertainty can be considered. The VS controller is designed to stabilize an uncertain system, quadratically. The design procedure for real systems is introduced via an implementation to the control of “Furuta pendulum”. To enhance the stability it is necessary to compensate the time‐varying nonlinear static friction of the actuator adequately, hence this problem is a good example to demonstrate the performance of the proposed VS control method. In the experiment, it will be shown that the VS control with the time‐varying sliding sector is superior to an orthodox chattering‐free VS control.
DESIGN OF A FLIGHT CONTROLLER FOR HYPERSONIC FLIGHT EXPERIMENT VEHICLE
Authors: Ochi Yoshimasa
Published: September 2010

National Aerospace Laboratory (NAL) and National Space Development Agency (NASDA) of Japan launched a hypersonic flight experiment vehicle (HYFLEX) for flight experiment of reentry phase to the top of the atmosphere in 1996. Flight condition in the experiment varied from an altitude of 107km and a speed of Mach 15 to an altitude of 30km and a speed of Mach 2. This paper describes design of a flight control system of the HYFLEX and evaluation of robustness against variations of command inputs and aerodynamic coefficients. A nonlinear simulation model that describes the vehicle motion has been made using the data obtained from wind tunnel experiments by NAL and NASDA. Linear models are computed from the nonlinear model for every second of the flight, assuming that the flight is a quasi‐trimmed one. Because the vehicle has a cylinder‐like configuration and takes a large angle of attack and a bank angle, coupling between longitudinal and lateral‐directional motions cannot be neglected; hence, the linear models include coupling terms. Averaging the linear models yields a nominal model for controller design, where the type‐1 linear quadratic (LQ) servo controller is employed for attitude control. Since the flight condition varies so much, it is difficult to control the vehicle using a single set of control gains. Therefore the flight period is segmented into eight intervals, for each of which a nominal linear model is computed, and then eight sets of feedback gain matrices are computed and scheduled as a function of flight time. The effectiveness and robustness of the flight control system are examined through computer simulation. Simulation results indicate that the control system works well even when attitude commands and aerodynamic parameters considerably deviate from nominal ones.
BACKLASH COMPENSATION WITH FILTERED PREDICTION IN DISCRETE TIME NONLINEAR SYSTEMS BY DYNAMIC INVERSION USING NEURAL NETWORKS
Authors: Campos J. , Lewis F. L. , Selmic R.
Published: September 2010

A dynamics inversion compensation scheme is designed for control of nonlinear discrete‐time systems with input backlash. This paper extends the dynamic inversion technique to discrete‐time systems by using a filtered prediction, and shows how to use a neural network (NN) for inverting the backlash nonlinearity in the feedforward path. The technique provides a general procedure for using NN to determine the dynamics preinverse of an invertible discrete time dynamical system. A discrete‐time tuning algorithm is given for the NN weights so that the backlash compensation scheme guarantees bounded tracking and backlash errors, and also bounded parameter estimates. A rigorous proof of stability and performance is given and a simulation example verifies performance. Unlike standard discrete‐time adaptive control techniques, no certainty equivalence (CE) or linear‐in‐the‐parameters (LIP) assumptions are needed.
SLIDING‐MODE LINEARIZATION TORQUE CONTROL OF AN INDUCTION MOTOR
Authors: Lin Shir‐Kuan , Fang Chih‐Hsing
Published: September 2010

This paper proposes a sliding‐mode linearization torque control (SMLTC) for an induction motor (IM). An ideal feedback linearization torque control method is firstly adopted in order to decouple the torque and flux amplitude of the IM. However, the system parameters are uncertainties, which will influence the control performance of the IM in practical applications. Hence, to increase the robustness of the IM drive for high‐ performance applications, this SMLTC aims to improve the immunity of those uncertainties. We modify the flux observer of Benchaib and Edwards [15] by means of the adaptive sliding‐mode method. This not only eliminates the estimation of the uncertainty bounds, but also improves the performance of sliding control. In addition, a practical application of the proposed SMLTC, with a model reference adaptive control (MRAC) scheme incorporated as the inner and outer loop controller used for position control, is also presented. Some experiments are presented to verify the control theory and demonstrate the robustness and effectiveness of the proposed SMLTC.
ON THE STABILITY OF OUTPUT FEEDBACK PREDICTIVE CONTROL FOR SYSTEMS WITH INPUT NONLINEARITY
Authors: Ding Bao‐Cang , Xi Yu‐Geng , Li Shao‐Yuan
Published: September 2010

For input saturated Hammerstein systems, a two‐step output feedback predictive control (TSOFPC) scheme is adopted. A receding horizon state observer is chosen, the gain matrix of which has a form similar to the linear control law. Through application of Lyapunov's stability theory, the closed‐loop stability for this kind of system is analyzed. The intermediate variable may or may not be available in real applications, and these two cases are considered separately in this paper. Furthermore, the domain of attraction for this kind of system is discussed, and we prove that it can be tuned to be arbitrarily large if the system matrix is semi‐stable. The stability results are validated by means of an example simulation.
RECURSIVE IDENTIFICATION OF PHYSICAL PARAMETERS IN A FLEXIBLE ROBOT ARM
Authors: Östring Måns , Gunnarsson Svante
Published: September 2010

Recursive identification of a physically parameterized model of a single link flexible robot arm is considered. The parameters are estimated using a recursive prediction error method applied to a linear continuous time model structure and discrete time data. The algorithm is applied to real data from an industrial robot, and three important parameters are identified using only measurements of the motor angle. The experiments show that the particular parameter that is estimated will have big influence on the algorithm behavior.
DECOUPLING WITH STABILITY: APPLICATION TO THE REAL TIME CONTROL OF A WATER STORING PLANT
Authors: Ruiz‐Leon J. , Sapiens A.J. , Čelikovsky S. , Torres J.A.
Published: September 2010

In this paper, results on decoupling with stability are applied to the real‐time control of a water storing plant. The conditions of decoupling with stability are verified on the approximate linear model of the system, and a decoupling state feedback providing pole assignment is designed. The state feedback controller achieves input‐output decoupling with stability, allowing controlling the levels of the water in the tanks independently. Simulation and experimental results are also presented showing a good performance of the designed controller.
DISTURBANCE REJECTION USING AN ILC ALGORITHM WITH ITERATION VARYING FILTERS
Authors: Norrlöf M.
Published: September 2010

An Iterative Learning Control disturbance rejection approach is considered and it is shown that iteration variant learning filters can asymptotically give the controlled variable zero error and zero variance. Convergence is achieved with the assumption that the relative model error is less than one. The transient response of the suggested ILC algorithm is also discussed using a simulation example.
FUNCTIONAL OBSERVERS FOR LINEAR SYSTEMS WITH UNKNOWN INPUTS
Authors: Deng Hua , Li Han‐Xiong
Published: September 2010

In this paper, a straightforward approach is presented to design functional observers for linear systems with unknown inputs. Necessary and sufficient conditions are provided for the existence of the observers. Some illustrated examples are included.
ESTIMATION OF AMPLITUDE OF OSCILLATIONS IN SLIDING MODE SYSTEMS CAUSED BY TIME DELAY
Authors: Acosta P. , Polyakov A. , Fridman L. , Strygin V.
Published: September 2010

Time delay does not allow realizing ideal sliding mode but implies oscillations in the state variable space. An estimation technique is developed for an upper bound of oscillation amplitude induced by bounded uncertain time delay presence.
DESIGN OF REDUCED‐ORDER FUNCTIONAL OBSERVERS FOR LINEAR SYSTEMS WITH UNKNOWN INPUTS
Authors: Trinh H. , Fernando T. , Nahavandi S.
Published: September 2010

This brief paper presents new conditions for the existence and design of reduced‐order linear functional state observers for linear systems with unknown inputs. Systematic procedures for the synthesis of reduced‐order functional observers are given. Numerical examples are given to illustrate the attractiveness and simplicity of the new design procedures.
MINIMIZING SERVICE DELAY OF APERIODIC TASKS IN DYNAMIC‐PRIORITY NON‐PREEMPTIVE HARD REAL‐TIME SYSTEMS
Authors: Oh Hoon , Park Hong Seong
Published: September 2010

A scheduling technique is presented to minimize service delay of aperiodic tasks in hard real‐time systems that employ dynamic‐priority scheduling and do not allow task preemption. In a real‐time scheduling process, the execution of periodic tasks can be deferred as long as this does not cause other tasks to violate their time constraints. However, aperiodic tasks that usually have urgent missions should complete execution as early as possible. In this paper, it is assumed that aperiodic tasks also have time constraints. Thus, the problem of deciding whether an aperiodic task with an unpredictable arrival time can be scheduled successfully or not is difficult to solve because delaying periodic tasks may cause them to fail to meet their time constraints. We present a dynamic scheduling technique to solve this problem which makes use of the symmetric property of a schedule. The maximum possible idle slot is always reserved at every scheduling point so that aperiodic tasks can be serviced immediately if the reserved idle slot is big enough to service them. The proposed technique also maximizes utilization of idle slots by reserving them for the longest possible time span.
COMMENTS ON «TUNING RULES FOR THE PID CONTROLLER USING A DMC STRATEGY»
Authors: Shen Jing‐Chung , Chiang Huann‐Keng
Published: September 2010

It is pointed out that the tuning rules for under damped system and non‐minimum phase system that given by Haeri is incorrect.
OPTIMAL REJECTION WITH ZERO STEADY‐STATE ERROR OF SINUSOIDAL DISTURBANCES FOR TIME‐DELAY SYSTEMS
Authors: Tang Gong‐You , Zhang Shu‐Mei
Published: September 2010

This paper studies the problem of optimal rejection with zero steady‐state error of sinusoidal disturbances for linear systems with time‐delay. Based on the internal model principle, a disturbance compensator is constructed to counterbalance the external sinusoidal disturbances, so that the original system can be transformed into an augmented system without disturbances. Then, with the introduction of a sensitivity parameter and expanding power series around it, the optimal disturbance rejection problem can be simplified to the problem of solving an infinite sum of a linear optimal control series without time‐delay or disturbance. The optimal control law for disturbance rejection with zero steady‐state error consists of accurate linear state feedback terms and a time‐delay compensating term, which is an infinite sum of an adjoint vector series. In the presented approach, iteration is required only for the time‐delay compensation series. By intercepting a finite sum of the compensation series, we obtain an approximate physically realizable optimal control law that avoids complex calculation. A numerical simulation shows that the algorithm is effective and easy to implement.
2‐D ALGEBRAIC TEST FOR ROBUST STABILITY OF QUASIPOLYNOMIALS WITH INTERVAL PARAMETERS
Authors: Xiao Yang
Published: September 2010

Determining the robust stability of interval quasipolynomials leads to a NP problem: an enormous number of testing edge polynomials. This paper develops an efficient approach to reducing the number of testing edge polynomials. This paper solves the stability test problem of interval quasipolynomials by transforming interval quasipolynomials into two‐dimensional (2‐D) interval polynomials. It is shown that the robust stability of an interval 2‐D polynomial can ensure the stability of the quasipolynomial, and the algebraic test algorithm for 2‐D s‐z interval polynomials is provided. The stability of 2‐D s‐z vertex polynomials and 2‐D s‐z edge polynomials were tested by using a Schur Table of complex polynomials.
STABILIZATION AND H∞ CONTROL FOR UNCERTAIN STOCHASTIC TIME‐DELAY SYSTEMS VIA NON‐FRAGILE CONTROLLERS
Authors: Xu Shengyuan , Lam James , Yang Guang‐Hong , Wang Jianliang
Published: September 2010

This paper considers the problems of robust non‐fragile stochastic stabilization and H∞ control for uncertain time‐delay stochastic systems with time‐varying norm‐bounded parameter uncertainties in both the state and input matrices. Attention is focused on the design of memoryless state feedback controllers which are subject to norm‐bounded uncertainties. For both the cases of additive and multiplicative controller uncertainties, delay‐independent sufficient conditions for the solvability of the above problems are obtained. The desired state feedback controller can be constructed by solving a certain linear matrix inequality.
CONSTRAINING HEAT INPUT BY TRAJECTORY OPTIMIZATION FOR MINIMUM‐FUEL HYPERSONIC CRUISE
Authors: Wächter M. , Sachs G.
Published: September 2010

Unsteady heat input effects are considered for the range cruise of a future hypersonic vehicle equipped with a turbo/ram jet engines combination. A realistic mathematical model for describing the unsteady heat effects has been developed. It is coupled to the model for the dynamics of the vehicle. To compute the heat load in hypersonic flight, several points on the vehicle surface are treated simultaneously. A two‐step technique consisting of an efficient optimization algorithm and an ordinary differential equations (ODE) solver is applied to generate a solution. The results show that the heat load can be significantly reduced, with only a small increase in fuel consumption.
A GRADIENT BASED ADAPTIVE CONTROL ALGORITHM FOR DUAL‐RATE SYSTEMS
Authors: Ding Feng , Chen Tongwen
Published: September 2010

In this paper, using a polynomial transformation technique, we derive a mathematical model for dual‐rate systems. Based on this model, we use a stochastic gradient algorithm to estimate unknown parameters directly from the dual‐rate input‐output data, and then establish an adaptive control algorithm for dual‐rate systems. We prove that the parameter estimation error converges to zero under persistent excitation, and the parameter estimation based control algorithm can achieve virtually asymptotically optimal control and ensure the closed‐loop systems to be stable and globally convergent. The simulation results are included.
CONTROL LAW FOR QUADRATIC STABILIZATION OF PERTURBED FUZZY TIME‐DELAY LARGE‐SCALE SYSTEMS VIA LMI
Authors: Wang Rong‐Jyue
Published: September 2010

In this paper, the perturbed continuous‐time large‐scale system with time delays is represented by an equivalent Takagi‐Sugeno type fuzzy model. First, two types of decentralized state feedback controllers are considered in this paper. Based on the Riccati‐type inequality, the Razumikhin theorem, and the delay‐dependent Lyapunov functional approach, some controller design approaches are proposed to stabilize the whole fuzzy time‐delay system asymptotically. In these design methods, both the delay‐independent and delay‐dependent stabilization criteria are derived. By Schur complement, these sufficient conditions can be easily transformed into the problem of LMI's. Moreover, the systems with all the time‐delays τlij(t) are the same for all rules (i.e., τlij(t) = τmij(t) = τijfor alll =m); the authors also propose a simpler and less conservative stabilizing criteria. A numerical example is given to illustrate the control design and its effectiveness.
NEURAL NETWORK‐BASED OPTIMAL ADAPTIVE TRACKING USING GENETIC ALGORITHMS
Authors: Kumarawadu Sisil , Watanabe Keigo , Izumi Kiyotaka , Kiguchi Kazuo
Published: September 2010

This paper presents the use of neural networks (NNs) and genetic algorithms (GAs) to enhance the output tracking performance of partly known robotic systems. Two of the most potential approaches of adaptive control, i.e., the concept of variable structure control (VSC) and NN‐based adaptive control, are ingeniously combined using GAs to achieve high‐performance output tracking. GA is used to make the maximum use of different performance characteristics of two self‐adaptive NN modules by finding the switching function which best combines them. The method will be valid for any rigid revolute robot system. Computer simulations on our active binocular head are included for illustration and verification.
STATE FEEDBACK CONTROLLER DESIGN OF NETWORKED CONTROL SYSTEMS WITH PARAMETER UNCERTAINTY AND STATE‐DELAY
Authors: Peng Chen , Yue Dong
Published: September 2010

This paper is concerned with the controller design of networked control systems. The continuous time plant with parameter uncertainty and state delay is studies. A new model of the networked control system is provided under consideration of the nonideal network conditions. In terms of the given model, a controller design method is proposed based on a delay dependent approach. The maximum allowable synthetical bounds related with the discarded data packet and network‐included delay and the feedback gain of a memoryless controller can be derived by solving a set of linear matrix inequalities for the stabilizablity of the networked control system based on Lyapunov functional method. An example is given to show the effectiveness of our method.
RECONSTRUCTING AND IDENTIFYING THE ROSSLER'S SYSTEM BY USING A HIGH GAIN OBSERVER
Authors: Ibáñez Carlos Aguilar , Jorge Sánchez H. , Miguel S. Suárez C. , G. R. Martínez , Garrido R.
Published: September 2010

A simple way to determine the parameters of Rössler's system based on a suitable output is presented in this paper. The fact that the nonlinear system is observable and algebraically identifiable with respect to the selected output, allows us to propose, in a first stage, a high‐gain observer to estimate the output time derivatives. And then, based on these facts two suitable schemes to recover the parameters are presented.
A LINEAR PROGRAMMING APPROACH FOR CALCULATION OF ALL STABILIZING PARAMETERS OF LEAD/LAG CONTROLLERS
Authors: Jalili Mahdi , Araabi Babak N.
Published: September 2010

Lead/Lag controllers are used extensively in industry and there is no straight forward and general solution to the problem of calculating all stabilizing parameters of Lead/Lag controllers. In this paper, a linear programming approach is proposed to calculate all stabilizing parameters of Lead/Lag type controllers for a given continuous‐time plant from an arbitrary order. The proposed method is based on the extension of Hermite‐Biehler Theorem, which has been proposed for calculating all stabilizing PID gains for a given continues‐time system in [6]. The linear programming nature of the proposed approach is its main advantage, which leads to the computer‐aided computation of the above problem. The applicability of the method is verified through a numerical example.
A MAS IMPLEMENTATION FOR SYSTEM IDENTIFICATION AND PROCESS CONTROL
Authors: González E. J. , Hamilton A. , Moreno L. , Marichal R. L. , Marichal G. N. , Toledo J.
Published: September 2010

In this paper, a MAS for system identification and process control is presented. In particular, this MAS implements a self‐tuning regulator (STR) scheme. It has adopted FIPA specifications because they have become a stronger standard in MAS development and they involve not only agent language specifications but also agent management and conversations. In this work, an Ontology Agent (OA) is included, using DAML + OIL as ontology language. The obtained results validate this approach in the implementation of well‐known algorithms for control process.
CONTROLLABILITY OF A CLASS OF SINGULAR SYSTEMS
Authors: Xie Guangming , Wang Long
Published: September 2010

In this paper, several different concepts of controllability are investigated for a class of linear singular systems which system parameters are piecewise constant. Necessary and sufficient geometric criteria for C‐controllability and R‐controllability of such systems are established, respectively. These conditions can be easily transformed into algebraic form. By applying the principle of duality, C‐observability is discussed as well. Furthermore, the intrinsic relationship between these results and existing results are also discussed. Then, a novel necessary, and sufficient criterion for C‐controllability of linear time‐invariant singular systems is derived as a byproduct.
PARAMETER‐DEPENDENT LYAPUNOV FUNCTION APPROACH TO STABILITY ANALYSIS AND DESIGN FOR POLYTOPIC SYSTEMS WITH INPUT SATURATION
Authors: Cao Yong‐Yan , Fang Kangling
Published: September 2010

This paper is devoted to stability analysis and synthesis of uncertain systems subject to input saturation. A new parameter‐dependent Lyapunov function analyzing approach is proposed to reduce the conservatism in stability analysis for the polytopic systems subject to input saturation. Some new stability conditions and a gain‐scheduling controller design method are then developed by the LMI optimization based approach. Numerical examples are used to demonstrate the effectiveness of the proposed design approach.
DIRECT ADAPTIVE CONTROL FOR NONLINEAR MATRIX SECOND‐ORDER SYSTEMS WITH TIME‐VARYING AND SIGN‐INDEFINITE DAMPING AND STIFFNESS OPERATORS
Authors: Haddad Wassim M. , Hayakawa Tomohisa , Stasko Michael C.
Published: September 2010

A direct adaptive control framework for a class of nonlinear matrix second‐order systems with time‐varying and sign‐indefinite damping and stiffness operators is developed. The proposed framework guarantees global asymptotic stability of the closed‐loop system states associated with the plant dynamics without requiring any knowledge of the system nonlinearities other than the assumption that they are continuous and bounded. The proposed adaptive control approach is used to design adaptive controllers for suppressing thermoacoustic oscillations in combustion chambers.
PASSIVITY ANALYSIS OF A MOTION CONTROL FOR ROBOT MANIPULATORS WITH DYNAMIC FRICTION
Authors: Canudas‐de‐Wit Carlos , Kelly Rafael
Published: September 2010

This paper addresses the motion control in joint space of robot manipulators with friction described by the generalized LuGre friction model. The paper extends the nonadaptive version of the Slotine and Li's control system originally designed for friction‐free manipulators to the case where a friction observer is incorporated to deal with friction. This observer corresponds to an adaptation of the friction compensation scheme proposed in Canudas de Wit et al., in 1975, 1995. Passivity concepts are the fundamental tools invoked in this paper to analyze the closed‐loop system behavior which lead to the conclusion of global asymptotic joint position tracking. A major advantage of this framework is that it allows to develop in a separate way the control law from the observer design provided that each part satisfies some passivity properties.
FREQUENCY WEIGHTED MODEL REDUCTION TECHNIQUE RETAINING HANKEL SINGULAR VALUES
Authors: Ghafoor Abdul , Sreera Victor , Treasure Richard
Published: September 2010

In this paper, a modification to Lin and Chiu's technique [1,2] of frequency weighted balanced truncation is presented. As in [1,2] the method is based on simulataneously diagonalizing the frequency weighted controllability and observability Gramians. Instead of obtaining the reduced order models from the truncated frequency weighted balanced realization as in conventional techniques [1,2], the models are obtained from the truncated augmented system realizations which ensures matching of the dominant frequency weighted Hankel singular values. The method is compared with the method of [2] using numerical examples.
IDENTIFICATION OF CONTINUOUS‐TIME POWER SPECTRA BY GENERALIZED FOURIER SERIES
Authors: Akçay Hüseyin , Türkay Semiha
Published: September 2010

In this paper, we present a generalized Fourier series based algorithm for the identification of continuous‐time, linear‐time invariant systems from power spectrum measurements. The algorithm is strongly consistent and it is used in the design of a linear shaping filter for a single‐track road power spectrum.
FUZZY SUPERVISORY CONTROL OF A DSP‐BASED MAGNETIC LEVITATION SYSTEM
Authors: Li Jen‐Hsing
Published: September 2010

This paper proposes a fuzzy supervisory control of a magnetic levitation system which the eZdsp F2812 is utilized as a controller. The discrete‐time model of the magnetic levitation system is derived and the stability is guaranteed by the root locus methodology. A fuzzy supervisory control is used to compensate for system nonlinearities.
A ROBUST ADAPTIVE CONTROL DESIGN FOR A CLASS OF UNCERTAIN NONLINEAR MARKOVIAN JUMP SYSTEMS
Authors: Yu Kang , Hongsheng Xi , Dali Zhang , Haibo Ji
Published: September 2010

A direct robust adaptive nonlinear control scheme for a class of uncertain nonlinear Markovian jump systems with nonlinear state‐dependent uncertainty is presented. The proposed scheme is Lyapunov‐based and guarantees the global uniform ultimate boundedness of the closed‐loop system in the mean sense. A numerical example is given to demonstrate the validity of the results.
STABILIZATION OF A COLLECTION OF LINEAR SYSTEMS WITH LIMITED INFORMATION
Authors: Yu Mei , Wang Long , Chu Tianguang , Xie Guangming
Published: September 2010

An iterative approach is proposed in this paper to stabilize a collection of linear systems with limited communication. Each linear system is viewed as a user on an idealized shared network which grants access only to a few users at a time. Sufficient conditions on the existence of network allocation sequences that preserve the stability of the collection are developed. The main idea of the iterative approach is that the controllers are designed to make full use of the old information to stabilize the entire collection when the network channel is not available for some of the system members. Simulated examples are presented to illustrate the proposed approach.
ADAPTIVE VARIABLE STRUCTURE CONTROL OF UNCERTAIN SYSTEMS CONTAINING UNKNOWN GAIN REDUCTION TOLERANCE
Authors: Yan Jun‐Juh , Lin Jui‐Sheng , Shyu Kuo‐Kai
Published: September 2010

In this paper, an adaptive variable structure controller (AVSC) is presented for a class of uncertain systems subjected to input nonlinearities. Using an adaptive technique, an AVSC is then proposed to ensure the asymptotical convergence of the switching quantity even without involving the bound of the gain reduction tolerance. On the switching surface, the investigated uncertain system still bears the insensitivity to the uncertainties and disturbances as the systems with linear input. An illustrative example is given to demonstrate the effectiveness of the proposed AVSC design method.
ADAPTIVE CONTROL DESIGN FOR NONLINEARLY PARAMETERIZED SYSTEMS WITH A TRIANGULAR STRUCTURE
Authors: Yokoi Kiyoshi , Hung N.V.Q. , Tuan H.D. , Hosoe Shigeyuki
Published: September 2010

A novel adaptive backstepping design for a class of nonlinearly parameterized systems with a triangular structure is proposed. Under the Lipschitz condition with respect to unknown parameters of the system, an effective adaptive controller is designed without the requirement on the compactness of the unknown parametric set. Especially, the proposed adaptive control enables the advantage of “tuning function concept”, which results in only one estimation law for the unknown parameters. Our simulation with induction motor model particularly shows the viability of the obtained results.
A STATE‐SPACE APPROACH TO QUANTIZATION COARSENESS FOR QUADRATIC STABILIZATION OF SINGLE‐INPUT SYSTEMS
Authors: Haimovich Hernan , Serony María M.
Published: September 2010

The input‐space‐based concept of quantization density recently introduced in the literature for single‐input systems can be regarded as a measure of the amount of information that a static feedback law employs. Here, we introduce a concept of quantizer coarseness for static quantizers from a purely state‐space standpoint, by means of explicit geometric considerations. We then analyze the links between this concept and the input‐space‐based quantization density. We thus provide an alternative state‐space‐based interpretation of coarse quantizers. We show how to directly apply the state‐space‐based concept of quantizer coarseness to design static output feedback strategies that employ quantizers of infimum density and to recover a well‐known result when a specific type of state quantizers is considered.
DISCRETIZATION OF COCURRENT REACTION‐ADVECTION PROCESSES PRESERVING THE FIR PROPERTY
Authors: Choi Jinhoon
Published: September 2010

A cocurrent reaction‐advection process represented by a system of first order hyperbolic partial differential equations (PDE's) has a desirable feature of finite impulse response (FIR) that allows easy identification and control. However, this desirable characteristic hasn't been exploited since all of the known finite difference discretization schemes do not preserve this desirable characteristic. In this note, we propose a finite difference discretization scheme that preserves the FIR property.
A STABLE ON‐LINE SELF‐TUNING OPTIMAL PID CONTROLLER FOR A CLASS OF UNKNOWN SYSTEMS
Authors: Huang Han‐Pang , Lin Ching‐Hung
Published: September 2010

In this paper, a novel self‐tuning method of optimal PID control laws is proposed for both continuous‐time systems and discrete‐time systems. The controlled plant is assumed to be unknown except the system order (or system delay) and the direction of transmitting control input. Through the minimization of PID gains subject to the Lyapunov stability based reaching condition, the tuning of the three PID control gains is transformed to solve the inequality constraint optimization problem. An unknown SISO nonlinear system subject to a unit step input, and the tracking control problem of the piezoelectric actuator (PZA) with unknown dynamics are simulated. The simulation results show that the excellent tracking performance can be achieved.
REAL‐TIME IMPLEMENTATION OF A DECENTRALIZED CONTROL FOR AN OPEN IRRIGATION CANAL PROTOTYPE
Authors: Begovich Ofelia , Felipe Juan C. , Ruiz Victor M.
Published: September 2010

This paper presents a real‐time implementation of a decentralized LQG controller to regulate the downstream levels at the end of the pools in a four‐pool open irrigation canal prototype with an upstream control concept. The objective of the controller is to keep the downstream level at a constant target value in despite of flow disturbances. Controller synthesis uses a “black box” input‐output identified linear model. A previous interaction analysis, via Relative Gain Array “RGA”, carried on the process model was made to verify the feasibility to design a decentralized control. The real‐time close‐loop results show satisfactory performance and they are compared with those obtained with a centralized LQG controller.
ROBUST POLE ASSIGNMENT VIA OUTPUT FEEDBACK IN DESCRIPTOR LINEAR SYSTEMS WITH STRUCTURAL PARAMETER PERTURBATIONS
Authors: Duan Guang‐Ren , Zhang Biao
Published: September 2010

The problem of eigenvalue assignment via output feedback with minimum sensitivity in multivariable descriptor linear systems with structural parameter perturbations is considered. Based on an eigenstructure assignment result for descriptor linear systems via output feedback and a result for generalized eigenvalue sensitivity problem of matrix pairs, parametric representations of the closed‐loop eigenvalue sensitivities to the perturbed elements in the open‐loop system matrices are obtained. An effective algorithm for eigenvalue assignment with minimum sensitivity in descriptor linear systems via output feedback is then proposed. The algorithm does not contain ‘going back’ procedures, and allows the closed‐loop eigenvalues to be conveniently optimized within desired regions. Computational results show its effect and simplicity.
USING LEAST SQUARE SVM FOR NONLINEAR SYSTEMS MODELING AND CONTROL
Authors: Zhang Haoran , Wang Xiaodong , Zhang Changjiang , Xu Xiuling
Published: September 2010

Support vector machine is a learning technique based on the structural risk minimization principle, and it is also a class of regression method with good generalization ability. The paper firstly introduces the mathematical model of regression least squares support vector machine (LSSVM), and designs incremental learning algorithms by the calculation formula of block matrix, then uses LSSVM to model nonlinear system, based on which to control nonlinear systems by model predictive method. Simulation experiments indicate that the proposed method provides satisfactory performance, and it achieves superior modeling performance to the conventional method based on neural networks, moreover it achieves well control performance.
Robust Neural Network Controller Design For A Biaxial Servo System
Authors: Yu Chih‐Hsien , Chen Tien‐Chi
Published: September 2010

A robust control method for synchronizing a biaxial servo system motion is proposed in this paper. A new neural network based cross‐coupled control and neural network techniques are used together to cancel out the skew error. In the proposed control scheme, the conventional fixed gain PID cross‐coupled controller (PIDCCC) is replaced with the neural network cross‐coupled controller (NNCCC) to maintain biaxial servo system synchronization motion. In addition, neural network PID position velocity and velocity controllers provide the necessary control actions to maintain synchronization while following a variable command trajectory. This scheme provides strong robustness with respect to uncertain dynamics and nonlinearities. The simulation results reveal that the proposed control structure adapts to a wide range of operating conditions and provides promising results under parameter variations and load changes.
A Novel Method Of Controller Design For Simultaneous Stabilization And Performance Improvement Of An Electromagnetic Levitation System
Authors: Banerjee Subrata , Kumar T. K. Sunil , Pal Jayanta , Prasad Dinkar
Published: September 2010

This paper describes design and implementation of a control philosophy for simultaneous stabilization and performance improvement of an electromagnetic levitation system. An electromagnetic levitation system is an inherently unstable and strongly nonlinear system. To determine the overall closed loop stability for such a system, cascade lead‐lag compensation has mostly been reported [1,2]. However, a single lead controller can not satisfy both stability and performance for such unstable systems [3]. Performance enhancement to satisfy the conflicting requirements of fast response with almost zero overshoot and zero steady state error has been successfully achieved by using a two loop controller configuration. The lead controller in the inner loop is designed to ensure stability while the outer loop PI controller is designed for performance enhancement. This approach decouples the twin requirements of stabilization (by the inner loop) and performance achievement (by the outer PI loop). The outermost PI controller has been designed using the ‘Approximate Model Matching’ technique [4]. The proposed control strategy has been implemented and the experimentation has been demonstrated successfully. Different experimental results have been included for verification.
Delay‐Dependent Robust Stability Criteria For Uncertain Neutral Systems With Mixed Time‐Varying Discrete And Neutral Delays
Authors: Parlakçi M. N. Alpaslan
Published: September 2010

In this paper, a new class of augmented quasi full size Lypunov‐Krasovskii functional is introduced for the robust stability of uncertain neutral systems with mixed time‐varying discrete and neutral delays. The nonlinear parameter perturbations and norm‐bounded uncertainties are taken into consideration separately. Delay‐dependent robust stability criteria are derived in the form of linear matrix inequalities. Numerical examples are presented to illustrate the significant improvement on the conservativeness of the delay bound over some reported results in the literature.
Adaptive Friction Compensation For Tracking Control Of Mechanisms
Authors: Guerra R. , Acho L.
Published: September 2010

Because friction is a phenomenon that is present in the vast majority of mechanical systems producing some unwanted effects such as tracking errors, limit cycles, and stick‐slip motion, friction model based compensation has been previously proposed. We present a simple adaptive friction compensator, developed from a simple friction model, that achieves the control objective (friction compensation). This simple model was effectively used to obtain a friction compensator with smooth terms avoiding the use of signum and absolute functions presented in previously reported works on friction compensation. Considering that the velocity is bound away from zero and using Lyapunov stability analysis, exponential stability of the closed loop system is shown; i.e., the tracking errors and the parameter estimation error converge exponentially to zero. Because our friction compensator is based on a simple friction model, numerical experiments using a more representative friction model are given to support our theoretical findings.
DSP‐BASED CONTROLLER DESIGN OF AN XY‐TABLE AND ITS APPLICATION TO VIRTUAL FISHING SYSTEM
Authors: Wang Ming‐Shyan , Lee Jing , Huang Chih‐Kai
Published: September 2010

The paper is focused on controller design of a hybrid XY‐table equipped with both a PMSM and a PMLSM and application of the XY‐table system to a virtual fishing system (VFS), which incorporates a boat simulator, an interactive fishing rod system, virtual reality fishing scenes, and a player in the loop. The fishing rod system consists of the XY‐table system acting as interactive force feedback hardware. Adaptive fuzzy control is adopted in the controller to track the command trajectory. The fishing boat is simulated by a three‐axis manipulator, which is composed of three pneumatic cylinders serving as extensive linkages. Through the shunt combination of the cylinders, the movement of the fishing boat can be arbitrarily adjusted. Summarily, VFS creates a spontaneous and interactive environment and offers the experience of fishing in a remote location on the sea at home or at the amusement park.
FAULT TOLERANT CONTROL OF FLEXIBLE SMART STRUCTURES USING ROBUST DECENTRALIZED FAST OUTPUT SAMPLING FEEDBACK TECHNIQUE
Authors: Bandyopadhyay B. , Manjunath T.C.
Published: September 2010

This paper presents the modeling, design and simulation of a Robust Decentralized Fast Output Sampling (RDFOS) feedback controller for the vibration control of a smart structure (flexible cantilever beam) when there is actuator failure. The beam is divided into 8 finite elements and the sensors / actuators are placed at finite element positions 2, 4, 6, and 8 as collocated pairs. The smart structure is modeled using the concepts of piezoelectric theory, Euler‐Bernoulli beam theory, Finite Element Method (FEM) techniques and the state space techniques. Four multi‐variable state‐space models of the smart structure plant are obtained when there is a failure of one of the four actuators to function. The effect of failure of one of the piezo actuators to function during the vibration of the beam is observed. The tip displacements, open and closed loop responses with and without the controller are observed. For all of these models, a common stabilizing state feedback gain F is obtained. A robust decentralized fast output sampling feedback gain L which realizes this state feedback gain is obtained using the LMI approach. In this designed control law, the control inputs to each actuator of the multi‐model representation of the smart structure is a function of the output of that corresponding sensor only and the gain matrix has got all off‐diagonal terms zero and this makes the control design a robust decentralized one. Then, the performance of the designed smart system is evaluated for Active Vibration Control (AVC). The robust decentralized FOS controller obtained by the designed method requires only constant gains and hence may be easier to implement in real time.