Showing papers by "Yuanqing Xia published in 2008"

Robust stabilisation for a class of discrete-time systems with time-varying delays via delta operators

Abstract: The problem of robust state feedback control using delta operator approach for a class of linear fractional uncertain systems with time-varying delays is investigated. Based on Lyapunov-Krasovskii functional in delta domain, a new delay-dependent state feedback controller is presented in terms of linear matrix inequalities. The sampling-period T is an explicit parameter, and thus it is easy to observe and analyse the effect of the state feedback controller with different sampling periods. The proposed method can unify some previous related continuous and discrete systems into the framework of delta operator systems. Numerical examples are given to illustrate the effectiveness of the developed techniques.

Design and Practical Implementation of Internet-Based Predictive Control of a Servo System

Abstract: This brief discusses the design and practical implementation of an Internet-based predictive control strategy. This novel control strategy can compensate for the random network delay and data dropout in an active way. In order to test the performance of the proposed control scheme, the offline simulation and practical implementation of an Internet-based servo control system are carried out. At the same time, the stability of the control scheme is also studied. The simulation and experimental results illustrate the feasibility and efficiency of the proposed Internet-based predictive control scheme.

A new global robust stability criteria for uncertain neural networks with fast time-varying delays

Abstract: This paper deals with the problem of robust stability for uncertain neural networks with time-varying delays. The system possesses time-varying and norm-bounded uncertainties. The time-varying delay function in this paper is not required to be either continuously differentiable, or its derivative less than one. Based on Lyapunov–Krasovskii functional approach, new delay-dependent and delay-derivative-dependent stability criteria are presented, which are given in terms of linear matrix inequalities (LMIs). Numerical examples are given to illustrate the effectiveness and less conservativeness of the developed techniques.

Robust delay-dependent sliding mode control for uncertain time-delay systems

Abstract: In this paper, the problem of robust sliding mode control for a class of linear continuous time-delay systems is studied. The parametric uncertainty considered is a modelling error type of mismatch appearing in the state. A delay-dependent sufficient condition for the existence of linear sliding surfaces is developed in terms of linear matrix inequality, based on which the corresponding reaching motion controller is designed. A numerical example is given to show the potential of the proposed techniques. Copyright © 2007 John Wiley & Sons, Ltd.

Descriptor discrete-time systems with random abrupt changes: stability and stabilisation

Abstract: This paper deals with the class of linear discrete-time systems with random abrupt changes also known as class of Markovian jump singular systems. The problems of stochastic stability and the stochastic stabilisation (using state-feedback control and static output feedback control) are tackled. Conditions in the LMI setting to design the appropriate gains of the controllers are developed. It is shown that all the addressed problems can be solved if the corresponding developed linear matrix inequalities (LMIs) are feasible. Numerical examples are employed to show the usefulness of the proposed results.

Robust Constrained Model Predictive Control Based on Parameter-Dependent Lyapunov Functions

Abstract: The problem of robust constrained model predictive control (MPC) of systems with polytopic uncertainties is considered in this paper. New sufficient conditions for the existence of parameter-dependent Lyapunov functions are proposed in terms of linear matrix inequalities (LMIs), which will reduce the conservativeness resulting from using a single Lyapunov function. At each sampling instant, the corresponding parameter-dependent Lyapunov function is an upper bound for a worst-case objective function, which can be minimized using the LMI convex optimization approach. Based on the solution of optimization at each sampling instant, the corresponding state feedback controller is designed, which can guarantee that the resulting closed-loop system is robustly asymptotically stable. In addition, the feedback controller will meet the specifications for systems with input or output constraints, for all admissible time-varying parameter uncertainties. Numerical examples are presented to demonstrate the effectiveness of the proposed techniques.

Robust H ∞ Control for Class of Discrete-Time Markovian Jump Systems with Time-Varying Delays Based on Delta Operator

Abstract: In this paper, the problem of robust H ∞ state feedback control using a delta operator approach for a class of linear fractional uncertain jump systems with time-varying delays is investigated. Based on the Lyapunov–Krasovskii functional in the delta domain, a new delay-dependent H ∞ state feedback controller which requires both robust stability and a prescribed H ∞ performance is presented in terms of linear matrix inequalities. The sampling period T appears as an explicit parameter; therefore, it is easy to observe and analyze the effect of the results with different sampling periods. Furthermore, the proposed method can unify some previous related continuous and discrete systems into the framework of delta operator systems. Numerical examples are presented to illustrate the effectiveness of the developed techniques

Decoupling Double-Loop Control System with ADRC

Abstract: An active disturbance rejection controller (ADRC) is proposed for decoupling double-loop control system. The ADRC consists of the tracking differentiator, the extended state observer and the nonlinear state error feedback. With this approach, the double-loop system with time delay is treated as two correlated control loops according to the best variable pairs selection, the interactions of two control loops can be estimated by the extended state observers, and the nonlinear state error feedback compensates the interactions. Finally, an experiment is designed to show the effectiveness of the proposed scheme.

Delay‐dependent robust passive control for a class of nonlinear systems with time‐varying delays

Abstract: In this paper, the problem of robust passive control for a class of nonlinear systems with time-varying delays is considered. The uncertainties investigated in this paper are norm bounded and time varying, and they enter all system matrices. Based on the Lyapunov–Krasovskii functionals approach, a new robust passive control criterion is proposed in terms of linear matrix inequalities, which is dependent on the size of time delay. We also design a state feedback controller that guarantees a robust asymptotically stable and strictly passive closed-loop system for all admissible uncertainties. Finally, two numerical examples are given to illustrate the effectiveness of the developed techniques. Copyright © 2007 John Wiley & Sons, Ltd.

Data fusion over network

Abstract: A new networked multi-sensor data fusion method which is based on Federated Filter is developed in this paper. The original system is far away form Data Processing Center (DPC), and measurements transmitted to DPC through network are used to produce a estimation of the measurement signal and Federated Filter is utilized to improve its accuracy. Due to the possible existence of both packet losses and network delay, it is necessary to check whether the Filter is stable, and consider how to process the delay data. Some sufficient conditions are presented for Kalman filter based Location Filters (LF) in the Federated Filter are stable, and a new method to process the delay data is developed here. Finally, an experiment is designed to show the effectiveness of the proposed scheme.

Observer-Based H8 Control for Discrete-Time Fuzzy Systems Using Fuzzy Lyapunov Functions

Abstract: The problem of observer-based Hinfin fuzzy control designs for discrete-time T-S fuzzy systems is considered in this paper. A sufficient LMI condition is proposed to guarantee the existence of the Hinfin controllers based on fuzzy observers for the discrete-time T-S fuzzy systems. It is shown that the controller and observer parameters can be obtained by solving a set of linear matrix inequalities that are numerically feasible with commercially available software. Finally, the validity and applicability of the approach are demonstrated by examples.