robust static output feedback stabilization for nonlinear discrete time systems with time delay via fuzzy control approach this paper addresses the problem of designing robust static output feedback controllers for nonlinear discrete time interval systems with time delays both in states and in control input in the approach we do not directly employ the lyapunov approach as do in most of traditional fuzzy control design approaches instead sufficient conditions for guaranteeing the robust stability for the considered systems are derived in terms of the matrix spectral norm of the closed loop fuzzy system the stability conditions are further formulated into linear matrix inequalities so that the desired controller can be easily obtained by using the matlab linear matrix inequality lmi toolbox finally an example is provided to illustrate the effectiveness of the proposed approach

fault detection for uncertain fuzzy systems an lmi approach this paper studies the problem of designing a robust fault detection system for uncertain takagi sugeno fuzzy models the worst case fault sensitivity measure is formulated in terms of linear matrix inequalities the existence of a robust fault detection system that guarantees i the l2 gain from a fault signal to a residual signal greater than a prescribed value and ii the l2 gain from an exogenous input to a residual signal less than a prescribed value is given in terms of the solvability of linear matrix inequalities numerical examples are used to illustrate the effectiveness of the proposed design techniques

a novel fuzzy framework for nonlinear system control nonlinear pid and gain scheduling controls have attracted much research interests in recent years these control strategies can accommodate some nonlinear characteristics by allowing the gains varied or rescheduled as a function of system states in this paper a novel fuzzy framework is developed to transfer this type of nonlinear controller to its fuzzy domain representation it is proved that the resulting fuzzy controller is functionally exactly identical to the original control system one of the benefits of the suggested approach is that it provides a well defined prototype for the design of fuzzy control system the resulting linguistic representation can facilitate investigation in linguistic terms into how the controller operates whereas expert knowledge can be effectively implemented to improve control performance the viability of the proposed mapping technique is demonstrated by using simulations corresponding to a flexible link robot

improved h control of discrete time fuzzy systems a cone complementarity linearization approach in this paper new results are presented for h analysis and synthesis problems of discrete time takagi sugeno ts fuzzy systems by defining a multiple lyapunov function a new sufficient condition guaranteeing the h performance of the ts fuzzy systems is first derived which is expressed by a set of linear matrix inequalities lmis both theoretical analysis and numerical examples show that such a new condition is less conservative than previous results obtained within the quadratic framework based on this new condition for h performance the corresponding h controller design problem is then investigated different from the traditional quadratic framework the synthesis problem is solved by exploiting the cone complementarity linearization ccl method together with a sequential minimization problem subject to lmi constraints obtained for the existence of admissible controllers which can be readily solved by using standard numerical software

simulation of fuzzy random variables this work deals with the simulation of fuzzy random variables which can be used to model various realistic situations where uncertainty is not only present in form of randomness but also in form of imprecision described by means of fuzzy sets utilizing the common arithmetics in the space of all fuzzy sets only induces a conical structure as a consequence it is difficult to directly apply the usual simulation techniques for functional data in order to overcome this difficulty two different approaches based on the concept of support functions are presented the first one makes use of techniques for simulating hilbert space valued random elements and afterwards projects on the cone of all fuzzy sets it is shown by empirical results that the practicability of this approach is limited the second approach imitates the representation of every element of a separable hilbert space in terms of an orthonormal basis directly on the space of fuzzy sets in this way a new approximation of fuzzy sets useful to approximate and simulate fuzzy random variables is developed this second approach is adequate to model various realistic situations

strictly positive definite functions on the unit circle we study strictly positive definite functions on the unit circle in the euclidean space of dimension two we develop several conditions pertaining to the determination of such functions the major result is obtained by considering the set of real numbers as a vector space over the field of rational numbers and then applying the kronecker approximation theorem and weyl s criterion on equidistributions

delta operator formulated discrete time approximations of continuous time systems given a continuous time system a technique to directly obtain an approximate delta operator formulated discrete time system spl delta system is presented for this purpose the analog of the well known boxer thaler integrators q forms applicable to shift operator formulated discrete time systems q systems are derived for spl delta systems next using these spl delta forms a method to obtain an approximate spl delta system of a given continuous time system is derived this algorithm is easily implementable in a computer with little computational burden it is shown that as sampling time decreases the spl delta system thus obtained yields the given continuous time system further verifying the close equivalence between this formulation and continuous time systems two examples illustrating advantages that may be gained by utilizing these spl delta forms in digitizing analog systems are also included

stability analysis and synthesis of fuzzy singularly perturbed systems in this paper we investigate the stability analysis and synthesis problems for both continuous time and discrete time fuzzy singularly perturbed systems for continuous time case both the stability analysis and synthesis can be parameterized in terms of a set of linear matrix inequalities lmis for discrete time case only the analysis problem can be cast in lmis while the derived stability conditions for controller design are nonlinear matrix inequalities nmis furthermore a two stage algorithm based on lmi and iterative lmi ilmi techniques is developed to solve the resulting nmis and the stabilizing feedback controller gains can be obtained for both continuous time and discrete time cases the reduced control law which is only dependent on the slow variables is also discussed finally an illustrated example based on the flexible joint inverted pendulum model is given to illustrate the design procedures

output feedback control for t s fuzzy delta operator systems with time varying delays via an input output approach in this paper the problem of induced l 2 disturbance attenuation control is investigated for discrete time takagi sugeno t s fuzzy delta operator systems with time varying delays and disturbance input via an input output approach a model transformation method is utilized to approximate the time varying delay in t s fuzzy delta operator systems by applying the scaled small gain ssg theorem and lyapunov krasovskii functional approach a sufficient condition is established to guarantee that the closed loop system is asymptotically stable and has an induced l 2 disturbance attenuation performance the existence condition of the dynamic output feedback controller can be solved via convex optimization problems finally simulation results are given to demonstrate the feasibility and effectiveness of the proposed method

robust stability of discrete time systems using delta operators the robust stability of discrete time systems formulated in terms of the delta delta operator is discussed that is given the nominal characteristic equation p delta of a discrete time system it is of interest to know how much the coefficients can be perturbed while preserving stability a procedure to obtain the maximum intervals for a perturbed polynomial p delta to still be stable is presented

robust control design for nonlinear stochastic partial differential systems with poisson noise fuzzy implementation abstract this study addresses the robust h control design problem for nonlinear stochastic partial differential systems nspdss with poisson noise under the environment of random external disturbance in the spatio temporal domain for nspdss with poisson noise the robust h control design needs to solve a complex hamilton jacobi integral inequality hjii for robust control despite random external disturbance in general it is very difficult to solve the nonlinear partial differential hjii in order to simplify the design procedure a fuzzy stochastic partial differential system is proposed to approximate the nspds based on fuzzy interpolation approach then a fuzzy stochastic spatial state space model is developed to represent the fuzzy stochastic partial differential system via the semi discretization finite difference scheme and the kronecker product based on this model the robust h control design is proposed to achieve the robust control of nspdss via solving linear matrix inequalities lmis instead of an hjii the proposed robust fuzzy h controller has an efficient ability to attenuate the effect of spatio temporal external disturbance on the controlled output of nspdss from the area energy point of view finally a robust h control of the nervous system is given to confirm the control performance of the proposed robust control design method for nspdss with poisson noise

robust semiglobally practical stabilization for nonlinear singularly perturbed systems in this work the problem of semiglobally practical stabilization is considered for nonlinear singularly perturbed systems with unknown parameters the composite lyapunov function for the full systems is established by both that of the slow subsystem and the boundary layer system a state feedback control law for the linear part of the slow subsystem and boundary layer system is proposed which renders the whole closed loop system semiglobally stable the upper bound expression of e is given to obtain the condition of asymptotic stability for the system a simulation example is given to demonstrate the effectiveness and feasibility of the controller

new results on delay dependent robust stability criteria of uncertain fuzzy systems with state and input delays this paper focuses on the delay dependent stability analysis and stabilization for uncertain t s fuzzy control systems with state and input delays the key features of the approach include the introduction of uncorrelated augmented matrix items into the lyapunov functional and the use of a tighter bounding technology in fact these techniques lead to more general and less conservative stability conditions that guarantee a wide stability region our delay dependent stability conditions thus obtained are given in terms of linear matrix inequalities lmis finally some examples are included to show that the proposed criteria improve the existing results significantly

technical communique further studies on lmi based relaxed stabilization conditions for nonlinear systems in takagi sugeno s form this paper further studies stabilization of nonlinear systems represented by a takagi sugeno t s discrete fuzzy model by extending a nonquadratic lyapunov function and applying a nonparallel distributed compensation non pdc law a new stabilization conclusion is presented that is a generalization of some previous results in the literature the new conclusion under a special situation is also suitable for a pdc law which presents to be more relaxed than some existing results an example is provided to demonstrate the effectiveness of the new conclusions

universal fuzzy models and universal fuzzy controllers for stochastic nonaffine nonlinear systems this paper investigates the universal fuzzy model and universal fuzzy controller problems for stochastic nonaffine nonlinear systems the underlying mechanism of stochastic fuzzy logic is first discussed and a stochastic generalized fuzzy model with new stochastic fuzzy rule base is then given based on their function approximation capability these kinds of stochastic generalized fuzzy models are shown to be universal fuzzy models for stochastic nonaffine nonlinear systems under some sufficient conditions an approach to stabilization controller design for stochastic nonaffine nonlinear systems is then developed through their stochastic generalized takagi sugeno t s fuzzy approximation models then the results of universal fuzzy controllers for two classes of stochastic nonlinear systems along with constructive procedures to obtain the universal fuzzy controllers are also provided respectively finally a numerical example is presented to illustrate the effectiveness of the proposed approach

brief paper adaptive sliding mode controller design based on t s fuzzy system models an adaptive sliding mode control asmc technique based on t s fuzzy system models is proposed in this paper for a class of perturbed nonlinear mimo dynamic systems in order to solve tracking problems a t s fuzzy model is firstly formed by utilizing fuzzy theorem to amalgamate a set of linearized dynamic equations the adaptive sliding mode controller is then designed based on this fuzzy model with perturbations the proposed control scheme can drive the dynamics of controlled system into a designated sliding surface in finite time and guarantee the property of asymptotical stability it is also shown that the information of upper bound of modeling errors as well as perturbations except the information of upper bound of input uncertainty is not required when using the proposed controller

robust model predictive control for discrete time takagi sugeno fuzzy systems with structured uncertainties and persistent disturbances in this paper robust model predictive control for uncertain discrete time takagi sugeno t s fuzzy systems with input constraints and persistent disturbances is considered the robust positively invariant set for t s fuzzy systems is investigated based on this result computation of the terminal constraint set is proposed which is of crucial importance in the robust predictive controller design a zero step predictive controller is discussed first which has a time varying terminal constraint set the recursive feasibility and input to state stability can be ensured then a novel controller with n step prediction is further proposed which can be used to deal with the case of fixed terminal constraint set the implementation of the n step controller involves both online and offline computations it is shown that a sequence of approximating robust one step sets can be computed offline then bisection searches are carried out online as well as a constrained convex optimization problem the n step controller guarantees that the system state can be steered to the terminal constraint set in less than n steps if the initial state lies in a specific region simulation results are finally presented to show the effectiveness of the proposed controllers

universal fuzzy controllers a collection b of fuzzy controllers is a universal fuzzy controller if and only if given any controllable process p it can also be controlled by some fuzzy controller in b this paper identifies a new type of universal fuzzy controller

strictly positive definite functions on spheres in euclidean spaces in this paper we study strictly positive definite functions on the unit sphere of the m dimensional euclidean space such functions can be used for solving a scattered data interpolation problem on spheres since positive definite functions on the sphere were already characterized by schoenberg some fifty years ago the issue here is to determine what kind of positive definite functions are actually strictly positive definite the study of this problem was initiated recently by xu and cheney proc amer math soc 116 1992 977 981 where certain sufficient conditions were derived a new approach which is based on a critical connection between this problem and that of multivariate polynomial interpolation on spheres is presented here the relevant interpolation problem is subsequently analyzed by three different complementary methods the first is based on the de boor ron general least solution for the multivariate polynomial interpolation problem the second which is suitable only for m 2 is based on the connection between bivariate harmonic polynomials and univariate analytic polynomials and reduces the problem to the structure of the integer zeros of bounded univariate exponentials finally the last method invokes the realization of harmonic polynomials as the polynomial kernel of the laplacian thereby exploiting some basic relations between homogeneous ideals and their polynomial kernels

approximation theory of fuzzy systems spl minus siso case in this paper the approximation properties of mimo fuzzy systems generated by the product inference are discussed we first give an analysis of fuzzy basic functions fbf s and present several properties of fbf s based on these properties of fbf s we obtain several basic approximation properties of fuzzy systems 1 basic approximation property which reveals the basic approximation mechanism of fuzzy systems 2 uniform approximation bounds which give the uniform approximation bounds between the desired control or decision functions and fuzzy systems 3 uniform convergent property which shows that fuzzy systems with defined approximation accuracy can always be obtained by dividing the input space into finer fuzzy regions and 4 universal approximation property which shows that fuzzy systems are universal approximators and extends some previous results on this aspect the similarity between fuzzy systems and mathematical approximation is discussed and an idea to improve approximation accuracy is suggested based on uniform approximation bounds

a descriptor system approach to fuzzy control system design via fuzzy lyapunov functions there has been a flurry of research activities in the analysis and design of fuzzy control systems based on linear matrix inequalities lmis this paper presents a descriptor system approach to fuzzy control system design using fuzzy lyapunov functions the design conditions are still cast in terms of lmis but the proposed approach takes advantage of the redundancy of descriptor systems to reduce the number of lmi conditions which leads to less computational requirement to obtain relaxed lmi conditions new types of fuzzy controller and fuzzy lyapunov function are proposed a salient feature of the lmi conditions derived in this paper is to relate the feasibility of the lmis to the switching speed of each linear subsystem to be exact to the lower bounds of time derivatives of membership functions to illustrate the validity and applicability of the proposed approach two design examples are provided the first example shows that the lmi conditions based on the fuzzy lyapunov function are less conservative than those based on a common standard lyapunov function the second example illustrates the utility of the fuzzy lyapunov function approach in comparison with a piecewise lyapunov function approach

lmi based relaxed nonquadratic stabilization conditions for nonlinear systems in the takagi sugeno s form this paper presents the stabilization analysis for a class of nonlinear systems that are represented by a takagi and sugeno ts discrete fuzzy model takagi and sugeno ieee trans systems man cybern 15 1 1985 116 the main result given here concerns their stabilization using new control laws and new nonquadratic lyapunov functions new relaxed conditions and linear matrix inequality based design are proposed that allow outperforming previous results found in the literature two examples are also provided to demonstrate the efficiency of the approaches

generalized guaranteed cost control with d stability and multiple output constraints abstract this paper is concerned with the problem of robust generalized guaranteed cost control with d stability and multiple output constraints for a class of linear uncertain systems being a combination of output performance indices a generalized cost function is considered to the linear polytopic uncertain systems described in a unified framework the aim is to design a state feedback controller such that the closed loop system is robust d stable and the upper bound of the generalized cost function is as small as possible subject to multiple output constraints based on parameter dependent lyapunov functions convex conditions for the existence of such controllers are presented in terms of linear matrix inequality the proposed approach shows a unified treatment of the linear systems in the differential shift and delta domains numerical examples are provided to illustrate the effectiveness of the design method

robust sliding mode control for uncertain time delay systems an lmi approach this note is devoted to robust sliding mode control for time delay systems with mismatched parametric uncertainties a delay independent sufficient condition for the existence of linear sliding surfaces is given in terms of linear matrix inequalities based on which the corresponding reaching motion controller is also developed the results are illustrated by an example

new results on h_ infty filtering for fuzzy time delay systems this paper is concerned with the h infin fuzzy filtering problem for a class of continuous time fuzzy systems with time varying delays the objective is to design a stable filter guaranteeing the asymptotic stability and a prescribed h infin performance of the filtering error system motivated by the parallel distributed compensation technique we design a new filter model in this paper filter parameter matrices can be obtained from the solution of a convex optimization problem in terms of linear matrix inequalities lmis when these lmis are feasible an explicit expression of a desired h infin fuzzy filter is given two numerical examples are provided to demonstrate the effectiveness and less conservativeness of the proposed design approach

multiobjective control for t s fuzzy singularly perturbed systems this paper investigates the problem of multiobjective control for a class of takagi sugeno t s fuzzy singularly perturbed systems based on a linear matrix inequality lmi approach a state feedback controller that depends on the singular perturbation parameter epsiv is developed such that 1 the h infin performance of the resulting closed loop system is less than or equal to some prescribed value 2 the closed loop poles of each local system are within a prespecified lmi stability region and 3 for a given upper bound epsivmacr for the singular perturbation parameter epsiv both 1 and 2 are guaranteed for all epsiv isin 0 epsivmacr it is shown that the epsiv dependent controller is well defined for any epsiv isin 0 epsivmacr and can be reduced to an epsiv independent one if epsiv is sufficiently small finally a practical example is given to show the feasibility and effectiveness of the obtained method

finite time h_ infty filtering for t s fuzzy discrete time systems with time varying delay and norm bounded uncertainties in this paper we investigate the filtering problem of discrete time takagi sugeno t s fuzzy uncertain systems subject to time varying delays a reduced order filter is designed with the augmentation technique a filtering error system with delayed states is obtained in order to deal with time delays in system states the filtering error system is first transformed into two interconnected subsystems by using a two term approximation for the time varying delay sufficient delay dependent conditions of finite time boundedness and h infty performance of the filtering error system are derived with the lyapunov function based on these conditions the filter design methods are proposed and the filter gain matrices can be obtained by calculating a set of linear matrix inequalities a numerical example is used to illustrate the effectiveness of the proposed approaches

fuzzy model based piecewise mathscr h _ infty static output feedback controller design for networked nonlinear systems this paper investigates the problem of robust h output feedback control for a class of nonlinear systems under unreliable communication links the nonlinear plant is represented by a takagi sugeno t s uncertain fuzzy model and the communication links between the plant and controller are assumed to be imperfect i e data packet dropouts occur intermittently which is often the case in a network environment stochastic variables that satisfy the bernoulli random binary distribution are adopted to characterize the data missing phenomenon and the attention is focused on the design of a piecewise static output feedback sof controller such that the closed loop system is stochastically stable with a guaranteed h performance based on a piecewise lyapunov function combined with some novel convexifying techniques the solutions to the problem are formulated in the form of linear matrix inequalities lmis finally simulation examples are also provided to illustrate the effectiveness of the proposed approaches

tabular method for determining root distribution of delta operator formulated real polynomials a tabular method for the investigation of real polynomial root distribution with respect to the circle spl verbar c 1 spl delta spl verbar 1 spl delta in the complex plane is presented such a procedure is useful in stability considerations of spl delta operator formulated discrete time systems with sampling time spl delta in particular when the characteristic polynomial contains literal coefficients we show that direct verification of stability may be preferable over techniques that utilize transformations when the sampling frequency is fast relative to the system bandwidth in addition as sampling frequency increases the relationship with the well known routh hurwitz table becomes apparent

robust h control for a class of discrete time fuzzy systems via delta operator approach in this paper we investigate a robust h control problem for a class of t s fuzzy systems with time delays by using delta operator approach it is known that a better control effect can be obtained by using delta operator approach than using shift operator approach for small sampling periods furthermore the delta operator can unify some previous related continuous and discrete fuzzy systems into fuzzy delta operator system framework based on lyapunov krasovskii functionals in delta domain a new fuzzy h state feedback controller is presented in terms of linear matrix inequalities some experiment results of an ball and beam model on a laboratory scale setup are presented to illustrate the effectiveness and potential for the developed techniques

improved finite word length characteristics in digital control using delta operators this paper examines some of the consequences of finite word lengths in digital control it is shown that in many cases of practical importance the usual shift operator formulation is inferior to an alternative formulation which we designate the delta operator approach this latter approach is shown to give better coefficient representation and less roundoff noise in many cases we thus argue that the shift operator and its associated z transform can be replaced by delta operators and their associated transform which we designate a transform an added advantage of this approach is that discrete designs and transforms converge to their continuous time counterparts as the sampling rate is increased

improved upper bounds for vertex cover this paper presents an o 1 2738 k kn time polynomial space algorithm for vertex cover improving the previous o 1 286 k kn time polynomial space upper bound by chen kanj and jia most of the previous algorithms rely on exhaustive case by case branching rules and an underlying conservative worst case scenario assumption the contribution of the paper lies in the simplicity uniformity and obliviousness of the algorithm presented several new techniques as well as generalizations of previous techniques are introduced including general folding struction tuples and local amortized analysis the algorithm also improves the o 1 2745 kk 4 kn time exponential space upper bound for the problem by chandran and grandoni

adaptive fuzzy decentralized dynamics surface control for nonlinear large scale systems based on high gain observer this paper discusses the adaptive fuzzy decentralized output feedback control problem for a class of nonlinear large scale systems the systems under study have unknown nonlinearities mismatched interconnections in control inputs and unmeasurable state variables therefore fuzzy logic systems are employed to approximate the unknown nonlinear functions in the control design and an adaptive high gain observer is established to estimate the unmeasured states based on the backstepping design technique and the dynamic surface control dsc approach a novel adaptive fuzzy decentralized output feedback control scheme is developed it is proved that the proposed control approach can ensure that all the signals of the closed loop system are semi globally uniformly ultimately bounded suub and the observer error and tracking error can all converge to a small neighborhood of the origin the effectiveness of the proposed approach is illustrated by simulation examples with comparisons with several existing methods

stability bounds of singularly perturbed discrete systems the authors propose a systematic approach to determine the exact stability bound of singularly perturbed discrete time systems by combining three conditions of the critical stability criterion with a bialternate product for discrete time systems the stability problems of two types of singularly perturbed discrete time systems can be solved via the derived scheme several examples are given to illustrate the proposed results

stabilization of nonlinear systems under variable sampling a fuzzy control approach this paper investigates the problem of stabilization for a takagi sugeno t s fuzzy system with nonuniform uncertain sampling the sampling is not required to be periodic and the only assumption is that the distance between any two consecutive sampling instants is less than a given bound by using the input delay approach the t s fuzzy system with variable uncertain sampling is transformed into a continuous time t s fuzzy system with a delay in the state though the resulting closed loop state delayed t s fuzzy system takes a standard form the existing results on delay t s fuzzy systems cannot be used for our purpose due to their restrictive assumptions on the derivative of state delay a new condition guaranteeing asymptotic stability of the closed loop sampled data system is derived by a lyapunov approach plus the free weighting matrix technique based on this stability condition two procedures for designing state feedback control laws are given one casts the controller design into a convex optimization by introducing some over design and the other utilizes the cone complementarity linearization idea to cast the controller design into a sequential minimization problem subject to linear matrix inequality constraints which can be readily solved using standard numerical software an illustrative example is provided to show the applicability and effectiveness of the proposed controller design methodology

h control design for fuzzy discrete time singularly perturbed systems via slow state variables feedback an lmi based approach this paper addresses the h control problem via slow state variables feedback for discrete time fuzzy singularly perturbed systems at first a method of evaluating the upper bound of singular perturbation parameter e with meeting a prescribed h performance bound requirement is given subsequently two methods for designing h controllers via slow state variables feedback are presented in terms of solutions to a set of linear matrix inequalities lmis in particular one of them can be used to improve the upper bound of the singular perturbation parameter e finally two numerical examples are given to illustrate the effectiveness of the proposed methods

pre specified performance based model reduction for time varying delay systems in fuzzy framework this paper attempts to provide a new solution to the model approximation problem for dynamic systems with time varying delays under the fuzzy framework for a given high order system our focus is on the construction of a reduced order model which approximates the original one in a prescribed error performance level and guarantees the asymptotic stability of the corresponding error system based on the reciprocally convex technique a less conservative stability condition is established for the dynamic error system with a given error performance index furthermore the reduced order model is eventually obtained by applying the projection approach which converts the model approximation into a sequential minimization problem subject to linear matrix inequality constraints by employing the cone complementary linearization algorithm finally two numerical examples are provided to illustrate the effectiveness of the proposed method

model reference adaptive control using the delta operator reference is made to a recent paper by g c goodwin r lozano leal d q mayne and r h middleton automatica vol 22 p 199 207 1986 where it is shown that a cancellation of nonminimum phase zeros appearing in discrete time model reference adaptive control mrac at a fast sampling rate can be easily avoided if the model to be identified is expressed in terms of the delta operator a new proof of stability of the mrac is given using the delta operator which in contrast to the proof given in the above paper does not require an assumption that a system consisting of a model determined by estimated parameters and a control law based on certainty equivalence principle is exponentially stable a simple parameterization is proposed for the discrete time mrac using the delta operator which allows application of the usual i e without dead zone estimation algorithms

low rank based multi input multi output takagi sugeno fuzzy modeling for prediction of molten iron quality in blast furnace abstract for complex blast furnace smelting systems with large time delay accurate prediction of molten iron quality indicators plays an important guiding role in blast furnace control recently some data driven multi input multi output mimo modeling methods have been proposed to model multiple molten iron quality indicators including molten iron temperature mit silicon content si phosphorus content p and sulfur content s however those data driven mimo models do not consider the inter indicator correlation which leads to the suboptimal model for the estimation of multiple molten iron quality indicators this paper proposed a novel mimo takagi sugeno t s fuzzy model with taking full account of the inter indicator correlation in the novel method the inter indicator correlation was explicitly modeled by a low rank learning in a latent space that overcame the great challenge of jointly determining the fuzzy rules of mimo t s model and the inter indicator correlation for the corresponding optimization problem an effective alternating optimization algorithm is presented the validity of the proposed method is verified by simulation and comparison with some related methods on real blast furnace data

modeling and controller design for complex flexible nonlinear systems via a fuzzy singularly perturbed approach this paper investigates the problems of modeling and controller design for complex flexible nonlinear systems cfnss based on a fuzzy singularly perturbed model a standard discrete time fuzzy singularly perturbed model fspm is firstly constructed to estimate cfnss based on a matrix spectral norm approach a static output feedback controller is designed which guarantees the resulting closed loop system is asymptotically stable the gains of controllers are obtained by solving a set of e independent linear matrix inequalities lmis so the ill conditioned problems caused by e can be easily avoided finally the proposed approach is applied to modeling and attitude control of flexible satellites in contrast to the existing results the proposed method has the following advantages i flexible vibrations can be effectively suppressed and ii the control performance is greatly improved as well as iii the control inputs do not need to be limited in controller design two practical examples are provided to illustrate the effectiveness of the presented approach from the simulation results it can be seen that the proposed approach can also effectively overcome the external disturbances and noises

h output feedback control of fuzzy system models under sampled measurements this paper studies the problem of control for a class of fuzzy system models by using a linear output controller the system under consideration is described by a continuous time fuzzy system model under sampled output measurements the premise variables of the fuzzy system model are assumed unmeasurable we develop a technique for designing an output feedback control law which globally stabilises this class of fuzzy system models a design algorithm for constructing the linear output controller is given a numerical simulation example is given to show the potential of the proposed techniques

h sub spl infin fuzzy output feedback control design for nonlinear systems an lmi approach addresses the problem of stabilizing a class of nonlinear systems by using an h sub spl infin fuzzy output feedback controller first a class of nonlinear systems is approximated by a takagi sugeno ts fuzzy model then based on a well known lyapunov functional approach we develop a technique for designing an h sub spl infin fuzzy output feedback control law which guarantees the l sub 2 gain from an exogenous input to a regulated output is less or equal to a prescribed value a design algorithm for constructing an h sub spl infin fuzzy output feedback controller is given in contrast to the existing results the premise variables of the h sub spl infin fuzzy output feedback controller are not necessarily to be the same as the premise variables of the ts fuzzy model of the plant a numerical simulation example is presented to illustrate the theory development

on observer based fault detection for nonlinear systems abstract this paper addresses analysis and integrated design of observer based fault detection fd for nonlinear systems to gain a deeper insight into the observer based fd framework definitions and existence conditions for nonlinear observer based fd systems are studied first then a scheme for an integrated design of observer based fd systems for affine nonlinear systems is proposed our work is considerably inspired by the study on input output stability and stabilization of nonlinear systems examples are given at the end of the paper to illustrate the theoretical results

robust reliable h control for fuzzy systems with random delays and linear fractional uncertainties this article studies the reliable robust stabilization problem for a class of uncertain takagi sugeno ts fuzzy systems with time varying delays the delay factor is assumed to be random delay which belongs to a given interval and parameter uncertainties are considered with linear fractional transformation form by implementing a proper novel lyapunov functional together with linear matrix inequality lmi approach a new set of delay dependent sufficient conditions is derived to guarantee the asymptotic stability of ts fuzzy system with a prescribed h performance index further a reliable robust h control design with an appropriate gain matrix has been derived to achieve the robust asymptotic stability for uncertain ts fuzzy system further schur complement and jensen s integral inequality are used to simplify the derivation in the main results the set of sufficient conditions is established using the relationship among the random time varying delay and its lower and upper bounds which can be easily solved by matlab lmi toolbox finally an illustrative example based on the truck trailer model is provided to show the effectiveness of the proposed new design technique

quadratic vertex kernel for split vertex deletion abstract a graph is called a split graph if its vertex set can be partitioned into a clique and an independent set split graphs have rich mathematical structure and interesting algorithmic properties making it one of the most well studied special graph classes in the split vertex deletion problem given a graph and a positive integer k the objective is to test whether there exists a subset of at most k vertices whose deletion results in a split graph in this paper we design a kernel for this problem with o k 2 vertices improving upon the previous cubic bound known also by giving a simple reduction from the vertex cover problem we establish that split vertex deletion does not admit a kernel with o k 2 edges for any 0 unless np conp poly

comparative study of finite wordlength effects in shift and delta operator parameterizations the sensitivity of the transfer function to finite wordlength effect errors in the implementation of the coefficients of both shift operator and delta operator parameterizations is analyzed the relationships between optimal realization sets in shift and delta operator are established it is shown that the optimal realization in delta operator parameterizations have better performance than those in their shift operator counterparts when the poles of the systems are clustered around z 1 a numerical example is given

robust h control for uncertain fuzzy systems with distributed delays via output feedback controllers this paper investigates the problem of robust h output feedback control for a class of uncertain fuzzy systems with distributed delays the system is described by a state space takagi sugeno fuzzy model with distributed delays and norm bounded parameter uncertainties the aim is to design a fuzzy dynamic output feedback controller which ensures the robust asymptotic stability of the closed loop system and guarantees an h norm bound constraint on disturbance attenuation for all admissible uncertainties in terms of linear matrix inequalities a sufficient condition for the solvability of this problem is presented finally simulation examples are provided to illustrate the effectiveness of the proposed design approach

h sub spl infin output feedback control of discrete time fuzzy systems with application to chaos control this paper presents an observer based h sub spl infin output feedback synthesis method for discrete time fuzzy dynamic systems based on a piecewise lyapunov function the basic idea of the approach is to design an observer based piecewise linear output feedback control law to guarantee the global stability with h sub spl infin performance of the resulting closed loop fuzzy control systems it is shown that the controller parameters can be obtained by solving a set of linear matrix inequalities lmis that are numerically feasible with commercially available software application to control chaotic systems is given to illustrate the effectiveness and advantages of the proposed method

sugeno type controllers are universal controllers abstract we show that given any continuous real valued function on a compact set there is a sugeno type controller that will approximate this function to any degree of accuracy an application of this result to fuzzy control is presented which shows that this type of sugeno controller is a universal controller

strictly positive definite kernels on subsets of the complex plane let z w x zw be a positive definite kernel and b a subset of in this paper we seek conditions in order that the restriction z w b x b zw be strictly positive definite since this problem has been solved recently in the cases in which b is either or the unit circle in our purpose here is twofold to present some results we obtained when attempting to solve the problem for the above and other choices of b and to acquaint the audience with some other questions that remain for two different classes of subsets we completely characterize the strict positive definiteness of the kernel we include a complete discussion of the case in which b is the unit circle of making a comparison with the classical problem of strict positive definiteness on the real circle

h control for fuzzy singularly perturbed systems in this paper both the state feedback and static output feedback h controllers for fuzzy singularly perturbed systems are investigated we give sufficient conditions for the existence of h controller such that the closed loop fuzzy control system is globally stable and achieves a prescribed level of disturbance attenuation for sufficiently small perturbation parameters the linear matrix inequality lmi approach is proposed to obtain the state feedback gains and a homotopy based iterative lmi algorithm is developed to get the static output feedback gains simulation results for two examples are included to demonstrate the effectiveness of the proposed approaches

control synthesis of singularly perturbed fuzzy systems this paper considers the problem of designing stabilizing and hinfin controllers for nonlinear singularly perturbed systems described by takagi sugeno fuzzy models with the consideration of the bound of singular perturbation parameter e for the synthesis problem of simultaneously designing the bound of e and stabilizing or hinfin controllers linear matrix inequalities lmi based methods are presented for evaluating the upper bound of e subject to stability or a prescribed hinfin performance bound constraint for the resulting closed loop system sufficient conditions are developed respectively for the stabilizing and hinfin control synthesis without the consideration of improving the bound of e new design methods are also given in terms of solutions to a set of lmis examples are given to illustrate the efficiency of the proposed methods

universal fuzzy controllers for a class of nonlinear systems in this paper we address the issues of universal fuzzy controllers we first present a universal function approximation theorem based on a fuzzy dynamic model then we show the results of universal fuzzy controllers for a large class of nonlinear systems

h state feedback controller design for continuous time t s fuzzy systems in finite frequency domain this paper is concerned with finite frequency h state feedback controller designs for continuous time takagi sugeno t s fuzzy systems a parallel distributed compensation pdc controller is designed in finite frequency domain with the aid of the generalized kalman yakubovich popov gkyp lemma the design problem is formulated as solving a set of linear matrix inequalities lmis simulation examples illustrate that the finite frequency design approach proposed in this paper receives better results than those of existing full frequency approaches

mean based fuzzy identifier and control of uncertain nonlinear systems a mean based adaptive fuzzy control scheme with state estimation performance is proposed for a class of uncertain nonlinear systems in the presence of only output measurement in the control scheme a mean based fuzzy identifier without prior knowledge of membership functions is merged into direct adaptive controller with a linear state estimator the structure of the mean based fuzzy identifier is nonlinear in the adjusted parameters in order to diminish the unfavorable influence of initially designing membership functions on control performance for the nonlinear structure a mean method is used to derive adaptive laws compared with conventional methods the advantage of the mean method is that the computation burden can be effectively alleviated because finding the derivative of fuzzy systems is not required in addition for the linear state estimator the state estimation performance with beforehand given attenuation parameter is established by the design of a compensative controller finally two examples are provided to demonstrate the applicability of the proposed scheme

prescribed performance adaptive fuzzy output feedback dynamic surface control for nonlinear large scale systems with time delays the adaptive fuzzy decentralized output feedback control method is proposed for a class of nonlinear large scale systems the considered nonlinear systems contain unstructured uncertainties unknown time varying delays and immeasurable states fuzzy logic systems are used to approximate the unstructured uncertainties and a fuzzy state observer is designed to estimate the unmeasured states based on the backstepping recursive design technique and the prescribed performance technique a new adaptive fuzzy output feedback control method is developed in order to overcome the problem of explosion of complexity inherent in the backstepping control design the dynamic surface control dsc technique is introduced into the control scheme based on lyapunov krasovskii functional it is proved that all the signals in the closed loop system are bounded and the tracking errors remain an adjustable neighborhood of the origin with the prescribed performance bounds the simulation examples and comparison with the previous control methods are provided to show the effectiveness of the proposed control approach

general takagi sugeno fuzzy systems with simplified linear rule consequent are universal controllers models and filters abstract takagi sugeno ts fuzzy systems have successfully been employed mainly in a trial and error manner to solve many control and modeling problems but their applications as signal filters remain to be fully explored compared to their nonfuzzy counterparts ts fuzzy controllers and models are difficult to be efficiently constructed because there is a large number of design parameters in the rule consequent the number grows dramatically with the increase of the number of input fuzzy sets and input variables furthermore there exists little published result on relationship between ts fuzzy controllers models filters and their nonfuzzy counterparts in this paper we investigate in relation to some popular nonfuzzy controllers models and filters analytical structure of a general class of multi input single output miso ts fuzzy systems that use arbitrary fuzzy rules with our recently introduced simplified linear rule consequent other components of the fuzzy systems in this study are general arbitrary continuous input fuzzy sets any type of fuzzy logic and and the generalized defuzzifier containing the widely used centroid defuzzifier as a special case we prove that the general miso ts fuzzy systems are 1 nonlinear variable gain controllers when implemented as controllers or 2 nonlinear time varying auto regressive with the extra input arx models when implemented as models or 3 nonlinear infinite impulse response iir or finite impulse response fir filters when implemented as filters furthermore we constructively prove that the general ts fuzzy systems with the simplified linear rule consequent are universal approximators and can approximate any continuous function in closed domain arbitrarily well the practical implication of these results is that these fuzzy systems with much less design parameters are always able to produce solutions to various control modeling and filtering problems we also establish sufficient conditions that can be used to calculate the number of input fuzzy sets and rules needed for achieving prespecified approximation accuracy

on distributed delay in linear control laws part ii rational implementations inspired from the spl delta operator this note proposes rational implementations for distributed delay in linear control laws the main benefit of doing so is the easy implementation of rational transfer functions the proposed approach was inspired from the spl delta operator the resulting rational implementation has an elegant structure of chained low pass filters the stability of each node can be guaranteed by the choice of the number n of the nodes the stability of the closed loop system can also be guaranteed since the h sup spl infin norm of the implementation error approaches 0 when n goes to spl infin moreover the steady state performance of the system is retained without the need to change the control structure

a new design of delay dependent robust cal h _ bm infty filtering for discrete time t s fuzzy systems with time varying delay this paper investigates the problem of delay dependent robust h infin filtering design for a class of uncertain discrete time state delayed takagi sugeno t s fuzzy systems the state delay is assumed to be time varying and of an interval like type which means that both the lower and upper bounds of the time varying delay are available the parameter uncertainties are assumed to have a structured linear fractional form based on a novel fuzzy basis dependent lyapunov krasovskii functional combined with finsler s lemma and an improved free weighting matrix technique for delay dependent criteria a new sufficient condition for robust h infin performance analysis is first derived and then the filter synthesis is developed it is shown that by using a simple linearization technique incorporating a bounding inequality a unified framework can be developed such that both the full order and reduced order filters can be obtained by solving a set of linear matrix inequalities lmis which are numerically efficient with commercially available software finally simulation examples are provided to illustrate the advantages and less conservatism of the proposed approach

robust fuzzy scheduling control for nonlinear systems subject to actuator saturation via delta operator approach this paper focuses on robust fuzzy scheduling control for nonlinear systems with actuation saturation via delta operator approach a class of t s fuzzy delta operator systems is extended to describe nonlinear systems subject to actuator saturation and linear fractional uncertainty moreover a set invariance condition is established for t s fuzzy delta operator systems based on the set invariance condition an optimization approach is proposed to estimate the domain of attraction for the t s fuzzy delta operator systems the domain of attraction is arbitrarily close to a null controllable region by the designed pdc control law or non pdc control law furthermore the non pdc control law is proposed by using fuzzy weighting dependent lyapunov function the effectiveness of the developed techniques is shown through a numerical example

fault detection and isolation based on fuzzy automata fuzzy automata are proposed for fault diagnosis the output of the monitored system is partitioned into linear segments which in turn are assigned to pattern classes templates with the use of membership functions a sequence of templates is generated and becomes input to fuzzy automata which have transitions that correspond to the templates of the properly functioning system if the automata reach their final states i e the input sequence is accepted by the automata with a membership degree that exceeds a certain threshold then normal operation is deduced otherwise a failure is diagnosed fault diagnosis of a dc motor and detection of abnormalities in the ecg signal are used as case studies

fuzzy h sub spl infin output feedback control design for singularly perturbed systems with pole placement constraints an lmi approach this paper examines the problem of designing an h sub spl infin output feedback controller with pole placement constraints for singular perturbed takagi sugeno ts fuzzy models we propose a fuzzy h sub spl infin output feedback controller that not only guarantees the spl lscr sub 2 gain of the mapping from the exogenous input noise to the regulated output to be less than some prescribed value but also ensures closed loop poles of each subsystem are in a prespecified linear matrix inequality lmi region in order to alleviate the numerical stiffness caused by the singular perturbation spl epsiv the design technique is formulated in terms of a family of spl epsiv independent linear matrix inequalities the proposed approach can be applied both standard and nonstandard singularly perturbed nonlinear systems a numerical example is provided to illustrate the design developed in this paper

observer based adaptive fuzzy tracking control for a class of uncertain nonlinear mimo systems this paper addresses the adaptive fuzzy tracking control problem for a class of uncertain nonlinear mimo systems with the external disturbances the adaptive fuzzy controllers are designed under the constraint that only system output is available for measurement then it is needed to design a state observer to estimate the unmeasured states in the observer design procedure two prominent advantages are that it does not require the sign of the control gain coefficient to be known and only two parameters need to be adjusted on line for each subsystem by using lyapunov analysis method it is proven that all the signals in the closed loop system are guaranteed to be bounded and the system outputs track the reference signals to a bounded compact set the feasibility of the proposed approach is validated by using two simulation examples

fuzzy input output controllers are universal approximators abstract in this paper we show that a fuzzy input output controller can approximate to any degree of accuracy a continuous fuzzy system this generalizes the known result that fuzzy controllers crisp input output can approximate continuous functions

technical communique fuzzy h output feedback control of nonlinear systems under sampled measurements this paper studies the problem of designing an h fuzzy feedback control for a class of nonlinear systems described by a continuous time fuzzy system model under sampled output measurements the premise variables of the fuzzy system model are allowed to be unavailable we develop a technique for designing an h fuzzy feedback control that guarantees the l 2 gain from an exogenous input to a controlled output is less than or equal to a prescribed value a design algorithm for constructing the h fuzzy feedback controller is given

dynamic output feedback h control synthesis for discrete time t s fuzzy systems via switching fuzzy controllers this paper studies the problem of dynamic output feedback h control of discrete time takagi sugeno t s fuzzy systems via a switched dynamic parallel distributed compensation dpdc scheme the considered switched dpdc control structure is determined based on the values of membership functions some new properties of membership functions are obtained and exploited to derive sufficient conditions for designing switching dpdc controllers that guarantee the stability and h performances of closed loop nonlinear systems the design conditions are given in terms of solvability of a set of linear matrix inequalities lmis it is shown that the new approach provides results at least as good as the corresponding dpdc methods a numerical example is given to illustrate the effectiveness of the proposed approach

a fuzzy lyapunov function approach to estimating the domain of attraction for continuous time takagi sugeno fuzzy systems this paper deals with stability analysis and control design problems for continuous time takagi sugeno t s fuzzy systems the first aim is to present less conservative linear matrix inequality lmi conditions to design controllers and assess the stability the second relevant contribution is to present a new strategy to find an inner estimate of the domain of attraction da via lmis the results are based on the fuzzy lyapunov functions flfs and non parallel distributed compensation non pdc approaches finally examples illustrate the effectiveness and merits of the proposed methods

kernel bounds for disjoint cycles and disjoint paths in this paper we show that the problems disjoint cycles and disjoint paths do not have polynomial kernels unless np conp poly thus these problems do not allow polynomial time preprocessing that results in instances whose size is bounded by a polynomial in the parameter at hand we build upon recent results by bodlaender et al 6 and fortnow and santhanam 20 that show that np complete problems that are or compositional do not have polynomial kernels unless np conp poly to this machinery we add a notion of transformation and obtain that disjoint cycles and disjoint paths do not have polynomial kernels unless np conp poly for the proof we introduce a problem on strings called disjoint factors and first show that this problem has no polynomial kernel unless np conp poly we also show that the related disjoint cycles packing problem has a kernel of size o klogk

the strong perfect graph theorem a graph g is perfect if for every induced subgraph h the chromatic number of h equals the size of the largest complete subgraph of h and g is berge if no induced subgraph of g is an odd cycle of length at least five or the complement of one the strong perfect graph conjecture berge 1961 asserts that a graph is perfect if and only if it is berge a stronger conjecture was made recently by conforti cornu ejols and vuiskovi c that every berge graph either falls into one of a few basic classes or admits one of a few kinds of separation designed so that a minimum counterexample to berge s conjecture cannot have either of these properties in this paper we prove both of these conjectures

robust stability of impulsive takagi sugeno fuzzy systems with parametric uncertainties this paper presents a kind of time varying impulsive takagi sugeno t s fuzzy model with parametric uncertainties in which each subsystem of the model is time varying several robust stabilities of time varying systems with parametric uncertainties such as general robust stability robustly asymptotical stability and exponential stability are studied using uniformly positive definite matrix functions and the lyapunov method specifically robust stability conditions of time invariant impulsive t s fuzzy systems are also derived in the formulation of quasi linear matrix inequalities qlmis and an iterative lmis algorithm is designed for solving qlmis finally a unified chaotic system with continuous periodic switch and a unified time invariant chaotic system are used for demonstrating the effectiveness of our respective results

universal fuzzy controllers based on generalized t s fuzzy models this paper investigates the universal fuzzy control problem based on generalized t s fuzzy models the universal approximation capability of the generalized t s fuzzy models is shown and an approach to robust controller design for general nonlinear systems based on this kind of generalized t s fuzzy models is developed the results of universal fuzzy controllers for two classes of nonlinear systems are then given and constructive procedures to obtain the universal fuzzy controllers are also provided an example is finally presented to show the effectiveness of our approach

parameterized complexity of vertex deletion into perfect graph classes vertex deletion problems are at the heart of parameterized complexity for a graph class f the f deletion problem takes as input a graph g and an integer k the question is whether it is possible to delete at most k vertices from g such that the resulting graph belongs to f whether perfect deletion is fixed parameter tractable and whether chordal deletion admits a polynomial kernel when parameterized by k have been stated as open questions in previous work we show that perfect deletion and weakly chordal deletion are w 2 hard when parameterized by k in search of positive results we study a restricted variant of the f deletion problem in this restricted variant the deleted vertices must be taken from a specified set x and we parameterize by x we show that for perfect deletion and weakly chordal deletion although this restriction immediately ensures fixed parameter tractability it is not enough to yield polynomial kernels unless np conp poly on the positive side for chordal deletion the restriction enables us to obtain a kernel with o x 4 vertices

robust stability functionals of state delayed systems with polytopic type uncertainties via parameterdependent lyapunov functions this paper considers the problem of robust stability for linear systems with a constant time delay in the state and subject to real convex polytopic uncertainty both delay independent and delay dependent stability conditions are characterized by linear matrix inequalities which allow the use of parameter dependent lyapunov functionals to analyse the system stability against parameter perturbations and therefore improve the conservativeness resulting from the single lyapunov functional in order to determine the maximum of time delay within which the system remains stable the problem can be cast into a generalized eigenvalue problem and solved by standard lmi solvers two examples are included to illustrate the proposed method

mamdani type fuzzy controllers are universal fuzzy controllers abstract this paper addresses the issues of universal fuzzy controllers and shows that the mamdani type fuzzy controllers are universal fuzzy controllers furthermore a constructive procedure is also presented to obtain the universal fuzzy controller if the reference fuzzy model is given

filter design for interval type 2 fuzzy systems with d stability constraints under a unified frame this paper investigates the problem of filter design for interval type 2 it2 fuzzy systems with d stability constraints based on a new performance index attention is focused on solving the h infty l 2 l infty passive and dissipativity fuzzy filter design problems for it2 fuzzy systems with d stability constraints in a unified frame under the new performance index frame using lyapunov stability theory a novel type of it2 filter is designed such that the filtering error system guarantees the prescribed h infty l 2 l infty passive and dissipativity performance levels with d stability constraints the existence condition of the it2 filter is expressed as the convex optimization problem and the filter parameters in the condition can be solved by the standard software the it2 fuzzy model and it2 fuzzy filter do not need to share the same lower and upper membership functions finally a numerical example is provided to show the effectiveness of the proposed results

h sub spl infin filtering for fuzzy singularly perturbed systems with pole placement constraints an lmi approach this paper addresses the problem of designing an h sub spl infin filter for a class of nonlinear singularly perturbed systems described by a takagi sugeno ts fuzzy model based on a linear matrix inequality lmi approach we develop a fuzzy h sub spl infin controller that guarantees that i the l sub 2 gain from an exogenous input to a filter error is less than or equal to a prescribed value and ii the poles of each local filter are within a prespecified region in order to alleviate the ill conditioning resulting from the interaction of slow and fast dynamic modes solutions to the problem are given in terms of linear matrix inequalities which are independent of the singular perturbation spl epsiv when spl epsiv is sufficiently small the proposed approach does not involve the separation of states into slow and fast ones and it can be applied not only to standard but also to nonstandard singularly perturbed nonlinear systems a numerical example is provided to illustrate the design developed in this paper

fuzzy adaptive observer backstepping control for mimo nonlinear systems in this paper a fuzzy adaptive backstepping output feedback control approach is developed for a class of multi input and multi output mimo nonlinear systems with unmeasured states using fuzzy logic systems to approximate the unknown nonlinear functions a fuzzy adaptive observer is designed for state estimation as well as system identification combining with the backstepping design techniques a fuzzy adaptive output feedback control is constructed recursively it is proved that the proposed fuzzy adaptive control approach can guarantee the semi global uniform ultimate boundedness for all the signals and the tracking error to a small neighborhood of the origin simulation studies illustrate the effectiveness of the proposed approach

technical communique observer based h fuzzy control design for t s fuzzy systems with state delays this paper is concerned with the problem of observer based h fuzzy control design for takagi sugeno t s fuzzy systems with time delay the main contribution is that an effective matrix decoupling technique is developed to derive a single step lmi condition for observer based h control design this overcomes the drawback of two step lmi approach in the literature when restricted to delay free fuzzy systems the present result is shown less conservative than existing ones an illustrative example is given to show the effectiveness of our results

universal fuzzy integral sliding mode controllers based on t s fuzzy models this paper addresses the universal fuzzy integral sliding mode controllers problem for continuous time multi input multi output nonlinear systems based on takagi sugeno t s fuzzy models by using the approximation capability of t s fuzzy models the nonlinear systems are expressed by uncertain t s fuzzy models with norm bounded approximation errors a novel fuzzy dynamic integral sliding mode control dismc scheme is then developed for the nonlinear systems based on their t s fuzzy approximation models one of the key features of the new dismc scheme is that the restrictive assumption that all local linear systems share a common input matrix which is required in most existing fuzzy integral sliding mode control ismc approaches is removed furthermore the results of universal fuzzy ismcs for two classes of nonlinear systems along with constructive procedures to obtain the universal fuzzy ismcs are provided respectively finally the advantages and effectiveness of the proposed approaches are illustrated via a numerical example

piecewise quadratic stability of fuzzy systems presents an approach to stability analysis of fuzzy systems the analysis is based on lyapunov functions that are continuous and piecewise quadratic the approach exploits the gain scheduling nature of fuzzy systems and results in stability conditions that can be verified via convex optimization over linear matrix inequalities examples demonstrate the many improvements over analysis based on a single quadratic lyapunov function special attention is given to the computational aspects of the approach and several methods to improve the computational efficiency are described