bluuebunny/crossref_metadata_2025_split huggingface dataset:
A NEW DESIGN APPROACH TO DELAY‐DEPENDENT ROBUST H∞ CONTROL FOR UNCERTAIN TIME‐DELAY SYSTEMS
Authors: Su Ning‐Jun , Su Hong‐Ye , Chu Jian 
Published: September 2010

ABSTRACTA new design approach to delay‐dependent robust stabilization and robust H∞ control for a class of uncertain time‐delay systems is provided in this paper. The sufficient conditions for delay‐dependent robust stabilization and robust H∞ control are derived based on a new state transformation and given in terms of linear matrix inequalities (LMI). Numerical examples are presented to show that the proposed results can be less conservative and can be used to deal with not only small but also large delay systems.
REVISITING THE ZIEGLER‐NICHOLS TUNING RULES FOR PI CONTROL — PART II THE FREQUENCY RESPONSE METHOD
Authors: Hägglund T. , J.Åström K. 
Published: September 2010

ABSTRACTThis paper presents an analysis of the Ziegler‐Nichols frequency response method for tuning PI controllers, showing that this method has severe limitations. The limitations can be overcome by a simple modification for processes where the time delay is not too short. By a major modification it is possible to obtain new tuning rules that also cover processes that are lag dominated.
DIGITAL PID CONTROLLER DESIGN FOR DELAYED MULTIVARIABLE SYSTEMS
Authors: Zhang Yongpeng , Shieh Leang‐San , Akujuobi Cajetan M. , Ali Warsame 
Published: September 2010

ABSTRACTA new methodology is proposed to design digital PID controllers for multivariable systems with time delays. Except for a few parameters that are preliminarily selected, most of the PID parameters are systematically tuned using the developed plant state‐feedback and controller state‐feedforward LQR approach, such that satisfactory performance with guaranteed closed‐loop stability is achieved. In order to deal with the modeling error owing to the delay time rational approximation, an IMC structure is utilized, such that robust stability is achieved, without need for an observer, and with improved online tuning convenience. Using the prediction‐based digital redesign method, the digital implementation is obtained based on the above‐proposed analog controller, such that the resulting mixed‐signal system performance will closely match that of the analog controlled system. An illustrative example is given for comparison with alternative techniques.
STABILITY OF LINEAR TIME‐INVARIANT OPEN‐LOOP UNSTABLE SYSTEMS WITH INPUT SATURATION
Authors: Wang Wen‐Liang A. , Mukai Hiro 
Published: September 2010

ABSTRACTThis paper analyzes the stability of a linear time‐invariant open‐loop unstable system subject to input saturation. First, we extend the idea of approximating the locally asymptotically stable region (controllable set) of the system for the case where the control is small enough to be unsaturated (inside the linear region), to the case when the control is allowed to saturate. It is shown that, when the Lyapunov descent criterion and the Kuhn‐Tucker Theorem is applied, a superior locally asymptotically stable region is found. A technique for approximating the locally asymptotically stable region is presented.
DISCRETIZING CONTINUOUS‐TIME CONTROLLERS WITH FUZZY LOGIC SYSTEMS AND ITS STABILITY ANALYSIS
Authors: Chuang Chen‐Chia , Jeng Jin‐Tsong , Lee Yung‐Cheng 
Published: September 2010

ABSTRACTIn this paper, a new method, applying the fuzzy logic system, is proposed to discretize the continuous‐time controller in computer‐controlled systems. All the continuous‐time controllers can be reconstructed by the proposed method under the Sampling Theorem. That is, the fuzzy logic systems are used to add nonlinearity and to approximate smooth functions. Hence, the proposed controller is a new smooth controller that can replace the original controller, independent of the sampling time under the Sampling Theorem. Consequently, the proposed controller not only can discretize the continuous‐time controllers, but also can tolerate a wider range of sampling time uncertainty. Besides, the input‐output stability is proposed for discretizing the continuous‐time controller of the fuzzy logic systems. Finally, computer simulation shows that the proposed method can easily reconstructthe continuous‐time controller and has very good robustness for different sampling times.
INCORPORATING PRACTICAL AND SYNTHESIS CONTENTS IN UNDERGRADUATE CONTROL EDUCATION
Authors: Hang C.C. 
Published: September 2010

ABSTRACTThis paper revisits the effort over the last decade in making undergraduate control education more useful and attractive to both the control engineers and the engineers at large. With the help of further coverage in new textbooks, more practical and synthesis contents in the control courses have been incorporated. Gaps still exist, particularly in the areas of PID control and auto‐tuning, fuzzy control, overall control strategy, control structure and systems thinking, and these will be elaborated. A major challenge is in the coverage of more practical and synthesis contents in the introductory common control course for all engineers. How this may be resolved is discussed. Finally, the need for new teaching approaches such as the use of interesting case studies and the use of problem‐based learning will be outlined.
OPTIMAL TRACKING CONTROL FOR DISCRETE TIME‐DELAY SYSTEMS WITH PERSISTENT DISTURBANCES
Authors: Tang Gong‐You , Sun Hui‐Ying , Liu Yi‐Min 
Published: September 2010

ABSTRACTOptimal tracking control (OTC) for discrete time‐delay systems affected by persistent disturbances with quadratic performance indexes is considered. Optimal tracking controller is designed based on a sensitivity approximation approach. By introducing a sensitivity parameter, we transform the original OTC problem into a series of difference equations without time‐advance on time‐delay terms. The obtained OTC law consists of analytic feedback and feedforward terms, and a compensation term, which is the sum of the infinite series of adjoint vectors. The compensation term can be obtained with an iterated formula for the adjoint vectors. A simulation example shows that the approximation approach is effective in tracking the reference input and robust with respect to exogenous persistent disturbances.
ROBUST FAULT DETECTION AND ISOLATION FOR UNCERTAIN LINEAR RETARDED SYSTEMS
Authors: Jiang Canghua , Zhou Donghua , Gao Furong 
Published: September 2010

ABSTRACTA robust fault detection and isolation scheme is proposed for uncertain continuous linear systems with discrete state delays for both additive and multiplicative faults. Model uncertainties, disturbances and noises are represented as unstructured unknown inputs. The proposed scheme consists of a Luenberger observer for fault detection and a group of adaptive observers, one for each class of faults, for fault isolation. The threshold determination and fault isolation are based on a multi‐observer strategy. Robustness to model uncertainties and disturbances can be guaranteed for the scheme by selecting proper thresholds. All the signals, i.e., the fault estimate and the state and output estimation errors of each isolation observer can be shown to be uniformly bounded, and the estimate of the fault by the matched observer is shown to be satisfactory in the sense of extended H2 norm. Furthermore, the sensitivity to fault and the fault isolability condition are analyzed also in the paper. Simulations of a heating process for detecting and isolating an actuator gain fault and an additive fault show the proposed scheme is effective.
A NEW INTEGRAL INEQUALITY APPROACH TO DELAY‐DEPENDENT ROBUST H∞ CONTROL
Authors: Zhang Xian‐Ming , Wu Min , Han Qing‐Long , She Jin‐Hua 
Published: September 2010

ABSTRACTA design method for the robust H∞ control of an uncertain linear system with a time‐varying state delay is proposed. First, an integral inequality that we recently obtained is employed to establish a new delay‐dependent bounded real lemma for a system with a time‐varying delay. The lemma uses neither a model transformation nor a bounding technique for cross terms. Then, the lemma is used in combination with a matrix decomposition method to derive delay‐dependent conditions for the existence of robust H∞ control based on linear matrix inequalities. Finally, some numerical examples are given to demonstrate the validity of the method.
A COMPARATIVE STUDY ON COMPUTATIONAL SCHEMES FOR NONLINEAR MODEL PREDICTIVE CONTROL
Authors: Minh Vu Trieu , Afzulpurkar Nitin 
Published: September 2010

ABSTRACTThis paper briefly reviews development of nonlinear model predictive control (NMPC) schemes for finite horizon prediction and basic computational algorithms that can solve the stable real‐time implementation of NMPC in space state form with state and input constraints. In order to ensure stability within a finite prediction horizon, most NMPC schemes use a terminal region constraint at the end of the prediction horizon — a particular NMPC scheme using a terminal region constraint, namely quasi‐infinite horizon, that guarantees asymptotic closed‐loop stability with input constraints is presented. However, when nonlinear processes have both input and state constraints, difficulty arises from failure to satisfy the state constraints due to constraints on input. Therefore, a new NMPC scheme without a terminal region constraint is developed using soften state constraints. A brief comparative simulation study of two NMPC schemes: quasi‐infinite horizon and soften state constraints is done via simple nonlinear examples to demonstrate the ability of the soften state constraints scheme. Finally, some features of future research from this study are discussed.
EVOLUTIONARY SEARCH FOR LIMIT CYCLE AND CONTROLLER DESIGN IN MULTIVARIABLE NONLINEAR SYSTEMS
Authors: Eftekhari M. , Katebi S. D. 
Published: September 2010

ABSTRACTA feature of many practical control systems is a Multi‐Input Multi‐Output (MIMO) interactive structure with one or more gross nonlinearities. A primary controller design task in such circumstances is to predict and ensure the avoidance of limit cycling conditions followed by achieving other design objectives. This paper outlines how such a system may be investigated using the Sinusoidal Input Describing Function (SIDF) philosophy quantifying magnitude, frequency and phase of any possible limit cycle operation. While Sinusoidal Input Describing function is a suitable linearization technique in the frequency domain for assessment of stability and limit cycle operation, it can not be employed in time domain. In order to be able to incorporate the time domain requirements in an overall controller design technique, the appropriate linearization technique suggested here is the Exponential Input Describing Function (EIDF).First, an evolutionary search based on a multi‐objective formulation is employed for the direct solution of the harmonic balance system matrix equation. The search is based on Multi‐Objective Genetic Algorithms (MOGA) and is capable of predicting specified modes of theoretically possible limit cycle operation.Second, the design requirements in time as well as frequency domain are formulated by a set of constraint inequalities. A numerical synthesis procedure also based on Multi‐Objective Genetic Algorithm is employed to adjust the initial compensator parameters to meet the imposed constraints. Robust stability and robust performance are investigated with respect to linearization uncertainty within the context of multiobjective formulation. In order to make the Genetic Algorithm (GA) search more amenable to design trade‐off between different and often contradictory specifications, a weighted sum of the functions is introduced. This criterion is subsequently optimized subject to the nonlinear system dynamics and a set of design requirements. Examples of use are given to illustrate the effectiveness of the proposed approach.
INTELLIGENT MODELING AND CONTROL OF WASHING MACHINE USING LOCALLY LINEAR NEURO‐FUZZY (LLNF) MODELING AND MODIFIED BRAIN EMOTIONAL LEARNING BASED INTELLIGENT CONTROLLER (BELBIC)
Authors: Lucas Caro , Milasi Rasoul M. , Araabi Babak N. 
Published: September 2010

ABSTRACTIntelligent control of home appliances has, in recent years, attracted much theoretical attention, as well as becoming a major factor for industrial and economic success and rapid market penetration. Washing Machines represent an important market. Intelligent control techniques are capable of providing useful means for both easier use and energy and water conservation. In this paper, the authors use two techniques that have successfully been used in other intelligent modeling and control applications. Firstly, the authors use a neuro‐fuzzy locally linear model tree system for data driven modeling of the machine. Secondly, the authors use a neural computing technique, based on a mathematical model of amygdala and the limbic system, for emotional control of the washing machine. The obtained results indicate the applicability of the proposed techniques in this important business sector.
A DIRECT APPROACH TO THE DESIGN OF ROBUST TRACKING CONTROLLERS FOR UNCERTAIN DELAY SYSTEMS
Authors: Ni Mao‐Lin , Li Guo 
Published: September 2010

ABSTRACTThe robust tracking and model following problem of linear uncertain time‐delay systems is investigated in this paper. By using the solution of the algebraic Riccati equation, this paper presents a direct approach to the design of robust tracking controllers. The system is controlled to track dynamic inputs generated from a reference model. In the case of matched uncertainties, the proposed controller ensures uniform ultimate boundedness of tracking errors and, furthermore, the bounds can be made arbitrarily small. In the case of mismatched uncertainties, a sufficient condition is presented such that the controller guarantees uniform ultimate boundedness of tracking errors. Compared with existing results, the main feature of the approach proposed in this paper is that it does not require any precompensator even for the non‐Hurwitz nominal system and, obviously, it is a direct method. It also employs linear controllers rather than nonlinear ones. Therefore, the designing method is simple for use and the resulting controller is easy to implement. Numerical examples show that this scheme can accommodate larger uncertainties and is likely to produce less conservative results.
STABILITY ANALYSIS OF UNCERTAIN DISCRETE‐TIME SYSTEMS WITH TIME‐VARYING STATE DELAY: A PARAMETER‐DEPENDENT LYAPUNOV FUNCTION APPROACH
Authors: Gao Huijun , Lam James , Chen Tongwen , Wang Changhong 
Published: September 2010

ABSTRACTThis paper presents several new robust stability conditions for linear discrete‐time systems with polytopic parameter uncertainties and time‐varying delay in the state. These stability criteria, derived by defining parameter‐dependent Lyapunov functions, are not only dependent on the maximum and minimum delay bounds, but also dependent on uncertain parameters in the sense that different Lyapunov functions are used for the entire uncertainty domain. It is established, theoretically, that these robust stability criteria for the nominal and constant‐delay case encompass some existing result as their special case. The delay‐dependent and parameter‐dependent nature of these results guarantees the proposed robust stability criteria to be potentially less conservative.
PERSISTENT EXCITATION IN A SHUNT DC MOTOR UNDER ADAPTIVE CONTROL
Authors: Huang Jeng‐Tze 
Published: September 2010

ABSTRACTThe adaptive input‐output linearizing control has been successful in achieving the asymptotic output tracking stability of a shunt DC motor, however, persistent excitation (PE) of the regressor has not been investigated. PE is known to be the necessary and sufficient condition for the exponential stability of a general adaptive system. Its fulfillment can be checked a priori when all the states entering the regressor track a prescribed trajectory asymptotically. However, it is rather difficult for this application because the regressor depends partly on the estimated parameters and the unobservable state which do not converge to any known signal at all. Nevertheless, it is found that such a task can actually be accomplished under some mild assumptions on the system and the reference trajectories. Simulation results confirming the assertion are given in the final sectien.
SIMPLE INSTABILITY CRITERION FOR A CLASS OF SINGULAR SYSTEMS WITH MULTIPLE TIME DELAYS
Authors: Sun Yeong‐Jeu 
Published: September 2010

ABSTRACTIn this paper, the instability for a class of singular systems with discrete and distributed time delays is investigated. Simple instability criterion, which is a delay‐dependent criterion, is derived to guarantee the instability of such systems. Finally, a numerical example is given to illustrate the use of the main result.
ON ROBUST STABILITY OF LINEAR NEUTRAL SYSTEMS WITH MIXED DELAYS AND NORM‐BOUNDED UNCERTAINTY
Authors: Yang Bin , Jiang Yanhong , Wang Jincheng , Zhong Chongquan , Wang Wei 
Published: September 2010

ABSTRACTThis paper investigates the robust stability of linear neutral systems with mixed delays and norm‐bounded uncertainty. Using new Lyapunov‐Krasovskii functionals, less conservative delay‐dependent robust stability conditions for such systems in terms of linear matrix inequalities (LMIs) are derived. Numerical examples show that the results obtained in this paper significantly improve the estimate of the stability limit over some existing results in other literature.
DECENTRALIZED STABILIZATION OF H FUZZY CONTROL FOR NONLINEAR MULTIPLE TIME‐DELAY INTERCONNECTED SYSTEMS
Authors: Hsiao Feng‐Hsiag , Xu Sheng‐Dong , Lin Chia‐Yen , Chou Yu‐Jun , Chen Yu‐Ching 
Published: September 2010

ABSTRACTA robustness design of fuzzy control is proposed in this paper to overcome the effect of modeling errors between nonlinear multiple time‐delay systems and fuzzy models. In terms of Lyapunov's direct method, a stability criterion is derived to guarantee the UUB (uniformly ultimately bounded) stability of nonlinear multiple time‐delay interconnected systems with disturbances. Based on this criterion and the decentralized control scheme, a set of fuzzy controllers is then synthesized via the technique of parallel distributed compensation (PDC) to stabilize the nonlinear multiple time‐delay interconnected systems and the Hcontrol performance is achieved in the mean time.
DEADLOCK AVOIDANCE FOR FLEXIBLE MANUFACTURING SYSTEMS WITH CHOICES BASED ON DIGRAPH CIRCUIT ANALYSIS
Authors: Zhang Wenle , Judd Robert P. 
Published: September 2010

ABSTRACTDue to existence of concurrent part flows and resource sharing in modern automated flexible manufacturing systems (FMS), deadlock is a common problem and its occurrence causes loss of productivity. When a manufacturing system is modeled by a digraph, existence of circuits in such a graph is a necessary condition for deadlock. Our previous work further showed that the knot and order of a circuit is closely related to impending deadlocks — a type of deadlock that is more difficult to detect. In this paper, we extend our previous work on deadlock avoidance for flexible manufacturing systems to allow choices in process flows (a.k.a., flexible part routing). Due to introduction of choices, part flow dynamics become more sophisticated and our previous results are no longer valid. A systematic circuit analysis is performed in this paper. New concepts such as broken circuit, basic circuit, choice circuit and supremal circuit are introduced to reduce significantly the number of circuits thus improving efficiency of our approach. The extended method is highly permissive with the adjusted effective free space calculation to capture more necessary parts flow dynamics, especially when multiple knots exist in the digraph model. The online policy runs in polynomial time once the set of basic circuits of the digraph is computed offline. Simulation results on selected examples are given.
DESIGN, DEVELOPMENT AND PERFORMANCE STUDIES OF EMBEDDED ELECTRONIC CONTROLLED ONE AXIS SOLAR TRACKING SYSTEM
Authors: Arasu A. Valan , Sornakumar T. 
Published: September 2010

ABSTRACTAn electronic embedded system controlled one axis automatic solar tracking system is designed and developed for parabolic trough collector employed for hot water generation. The electronic circuit diagram with detailed description and performance of the tracking system are presented. The position of Sun is successfully detected using light dependent resistors, with an accuracy of 0.1°. The accuracy is much greater than the required 0.5°, which is determined from the collector acceptance angle test. The tracking mechanism maximum error is found to be 0.18°. The tracking mechanism has proved to be sufficiently accurate for the present solar energy application i.e. hot water generation. Extensive testing of the parabolic trough solar collector hot water generation system proved that the tracking mechanism is very effective.
IS A MIXED DESIGN OF OBSERVER‐CONTROLLERS FOR TIME‐DELAY SYSTEMS INTERESTING?
Authors: Sename O. 
Published: September 2010

ABSTRACTThis paper deals with H∞ observer‐based feedback control for linear time‐delay systems, in the framework of delay independent stability. We will propose a new LMI solution to observer‐controller design that ensures a disturbance attenuation level for the controlled output as well as for the state estimation error, which is an open problem. This will be compared with a well‐known solution and with a usual strategy in control which consists in designing the observer and the controller separately. Our aim is to try to bring a positive answer to the following question: is there an interest to solve the problem in a single (unique) formulation or should we design separately the observer and the controller? An application to a wind tunnel model is provided to emphasize the interest of the given results, particularly in comparison with existing results on H∞ observer‐based control.
DISTURBANCE DECOUPLING FOR NONLINEAR TIME‐DELAY SYSTEMS
Authors: Mérquez‐Martínez L.A. , Moog C.H. 
Published: September 2010

ABSTRACTThe disturbance decoupling problem is studied for a general class of nonlinear systems with multiple delays. Necessary and sufficient conditions are given for the solvability of the problem, in geometric terms involving so‐called controlled invariant modules. An example is included which shows that there is no unique “standard” solution to disturbance decoupling in opposition to the well known situation of systems without delays.
COMPLEXITY RELAXATION OF THE TENSOR PRODUCT MODEL TRANSFORMATION FOR HIGHER DIMENSIONAL PROBLEMS
Authors: Baranyi Péter , Petres Zoltén , Korondi Péter , Yam Yeung , Hashimoto Hideki 
Published: September 2010

ABSTRACTThe Tensor Product (TP) model transformation method was proposed recently as an automated gateway between a class of non‐linear models and linear matrix inequality based control design. The core of the TP model transformation is the higher order singular value decomposition of a large sized tensor, which requires high computational power that is usually outside of a regular computer capacity in cases of higher dimensionality. This disadvantage restricts the utilization of the TP model transformation to models having smaller dimensionality. The aim of this paper is to propose a computationally relaxed version of the TP model transformation. The paper also presents a 6 dimensional example to show the effectiveness of the modified transformation.
H∞ CONTROL FOR DELAYED DISCRETE FUZZY SYSTEMS
Authors: Liu Huaping , Sun Fuchun , Sun Zengqi 
Published: September 2010

ABSTRACTIn this paper, the H∞ controller design for discrete‐time fuzzy systems with time‐delay is investigated. An improved Lyapunov‐ Krasovskii function which is explicitly dependent on the membership functions is proposed to obtain less conservative results. The controller design problem can be cast into a set of linear matrix inequalities. Finally, a simulation example is given to show the effectiveness of the proposed design approaches.