Robust H-infinity fault-tolerant control for uncertain descriptor systems by dynamical compensators

The problem of robust H-infinity fault-tolerant control against sensor failures for a class of uncertain descriptor systems via dynamical compensators is considered. Based on H-infinity theory in descriptor systems, a sufficient condition for the existence of dynamical compensators with H-infinity fault-tolerant function is derived and expressions for the gain matrices in the compensators are presented. The dynamical compensator guarantees that the resultant colsed-loop system is admissible; furthermore, it maintains certain H-infinity norm performance in the normal condition as well as in the event of sensor failures and parameter uncertainties. A numerical example shows the effect of the proposed method.

Decentralized robust guaranteed cost control for a class of interconnected singular large-scale systems with time-delay and parameter uncertainty

The decentralized robust guaranteed cost control problem is studied for a class of interconnected singular large-scale systems with time-delay and norm-bounded time-invariant parameter uncertainty under a given quadratic cost performance function. The problem that is addressed in this study is to design a decentralized robust guaranteed cost state feedback controller such that the closed-loop system is not only regular, impulse-free and stable, but also guarantees an adequate level of performance for all admissible uncertainties. A sufficient condition for the existence of the decentralized robust guaranteed cost state feedback controllers is proposed in terms of a linear matrix inequality （LMI） via LMI approach. When this condition is feasible, the desired state feedback decentralized robust guaranteed cost controller gain matrices can be obtained. Finally, an illustrative example is provided to demonstrate the effectiveness of the proposed approach.

Passivity Control for Uncertain T-S Fuzzy Descriptor Systems

By means of matrix decomposition method a criterion is presented for the admissibility of T-S fuzzy descriptor system. Then, the problem of passivity control is studied for a kind of T-S fuzzy descriptor system with uncertain parameters, and sufficient conditions which make the closed-loop system admissible and strictly passive are obtained based on linear matrix inequality (LMI). The nonstrict LMIs restricted conditions which characterize the descriptor system are transformed into strict ones, so testing admissibility and passivity of the system can be finished simultaneously. The design scheme of state feedback controller is also obtained. Finally, a numerical example is given to show the validity and feasibility of the proposed approach.

Non-fragile observer-based passive control for descriptor systems with time-delay

This paper investigates the problem of non-fragile observer-based passive control for descriptor systems with time-delay. The perturbations in both the control gain and observer gain of the observer-based controller are considered. For the cases of the additive perturbations and multiplicative perturbations, sufficient conditions are given such that the closed-loop systems are admissible and passive with dissipation η. The observer-based controller gains could be obtained from the solutions of linear matrix inequalities （LMIs）. Moreover, the maximum dissipation of the system is provided. Simulation examples are given to show the effectiveness of the deign methods.

Integral sliding mode control of time-delay systems with mismatching uncertainties

A linear matrix inequality （LMI）-based sliding surface design method for integral sliding mode control of uncertain time- delay systems with mismatching uncertainties is proposed. The uncertain time-delay system under consideration may have mis- matching norm bounded uncertainties in the state matrix as well as the input matrix, A sufficient condition for the existence of a sliding surface is given to guarantee asymptotic stability of the full order slJdJng mode dynamics. An LMI characterization of the slid- ing surface is given, together with an integral sliding mode control law guaranteeing the existence of a sliding mode from the initial time. Finally, a simulation is given to show the effectiveness of the proposed method.

Robust Stabilization for Linear Time-varying Uncertain Periodic Descriptor Systems

这个问题赶出为线性变化时间的不明确的周期的描述符系统的稳定被重游。为线性变化时间的不明确的周期的描述符系统基于柔韧的稳定性的概念，为柔韧的稳定性的一个必要、足够的条件被提出。柔韧的稳定问题也被学习，相应必要、足够的条件用双系统的符号被给。获得的矩阵不平等条件能被转变到与一些免费矩阵的介绍的线性矩阵不平等一，它使分析和设计过程简单、可靠。

Observer-based adaptive control of uncertain time-delay switched systems with stuck actuator faults

This paper concerns the observer-based adaptive control problem of uncertain time-delay switched systems with stuck actuator faults. Under the case where the original controller cannot stabilize the faulty system, multiple adaptive controllers are designed and a suitable switching logic is incorporated to ensure the closed-loop system stability and state tracking. New delay-independent sufficient conditions for asymptotic stability are obtained in terms of linear matrix inequalities based on piecewise Lyapunov stability theory. On the other hand, adaptive laws for on-line updating of some of the controller parameters are also designed to compensate the effect of stuck failures. Finally, simulation results for reference [1] model show that the design is feasible and efficient.

Robust H_∞ control for fuzzy descriptor systems with state delay

The problem of robust H ∞ fuzzy state feedback control for uncertain fuzzy descriptor systems with state delay is solved. In the case that time-varying uncertainties are in all parameter matrices, sufficient conditions for the existence of fuzzy state feedback controller are presented in terms of linear matrix inequality (LMI). The proposed robust H ∞ control laws guarantee that the resulting closed-loop system is regular, impulse free, and stable with prescribed H ∞ norm bounded constraint for all admissible uncertainties. Finally, a numerical example is provided to demonstrate the validity of the proposed method.

H-infinity output feedback control for descriptor systems with delayed states

This paper considers the H-infinity dynamic output feedback control for descriptor systems with delay in states. The controller is a descriptor system without delay. Several equivalent sufficient conditions for the existence of one descriptor dynamic controller without impulsive models are given. Furthermore the explicit expression of the desired controller is obtained. The detailed design of the controller is presented using the cone complementarity linearization iterative algorithm and the LMI method. A ntumerical example is shown to illustrate the designed method.

Guaranteed cost control of uncertain system with input time-delay

For the uncertain continuous-time systems with input time-delay that widely exist in the production processes, we can get the existent conditions for the guaranteed cost control of these systems by using the Lyapunov stability theory, linear matrix inequalities theory and quadratic cost criterion. We can achieve the guaranteed cost control of this system by solving a matrix inequality. A state feed back guaranteed cost control law can be constructed by solving certain parameter-dependent Riccati matrix equation.

On exponential stability for systems with state delays

This paper considers the issue of delay-dependent exponential stability for time-delay systems. Both nominal and uncertain systems are investigated. New sufficient conditions in terms of linear matrix inequalities(LMIs) are obtained. These criteria are simple owing to the use of an integral inequality. The model transformation approaches,bounding techniques for cross terms and slack matrices are all avoided in the derivation. Rigorous proof and numerical examples showed that the proposed criteria and those based on introducing slack matrices are equivalent.

Adaptive Output Feedback Regulation for a Class of Uncertain Feedforward Time-Delay Nonlinear Systems

This paper addresses the global output feedback regulation problem for a class of uncertain feedforward time-delay nonlinear systems.Unlike to the previous works,the nonlinear functions in the class of systems under consideration are dominated by an input-output function multiplied by an unknown parameter and linear unmeasured states.By using only one dynamic gain and an appropriate Lyapunov-Krasovskii functionals,it is shown that the closed-loop system is globally asymptotically stable.Finally,a numerical example is provided to illustrate the effectiveness of the proposed design scheme.

Robust passive control of uncertain switched time-delay systems: a sliding mode control design

In this paper, the problem of sliding mode control （SMC） with passivity for a class of uncertain switched time-delay systems is studied. By means of the multiple Lyapunov functions techniques, a delay-dependent sufficient condition for the existence of linear sliding surface of subsystem is deduced in which the solution to the switched sliding mode dynamics is robustly exponentially stable and passive under a state-based switching law. Moreover, the sliding mode controller is designed to drive the system trajectories onto the predefined sliding surface of subsystem in finite time. Finally, a numerical example is provided to illustrate the effectiveness of the proposed method.

STABILITY CRITERIA FOR A CLASS OF UNCERTAIN SYSTEMS WITH TIME-DELAY

Some stability criteria are obtained for a class of uncertain systems with time-delay usingLyapunov functional and analytic techniques. It is easy to check the criteria by making use of theboundedness of the uncertainties.

离散广义系统具有完整性的鲁棒二次稳定

研究时不变不确定离散广义系统具有完整性的鲁棒二次稳定问题.首先,给出不确定离散广义系统鲁棒二次稳定的充要条件.其次,利用广义代数R iccati不等式,设计状态反馈使得不确定离散广义系统鲁棒二次稳定.进一步,给出状态反馈设计方法,使得不确定离散闭环广义系统在执行器正常以及部分出现故障情况下,都保持鲁棒二次稳定.即不确定广义系统具有完整性.同时,还讨论了所给的广义代数R iccati不等式的求解问题.最后给出数字例子来验证所给结果的有效性.

具有Frobenius范数界的不确定广义系统鲁棒二次稳定完整性

考虑带有Frobenius范数界的不确定广义系统具有完整性的鲁棒二次稳定问题.通过代数Riccati不等式给出不确定广义系统在状态反馈下所构成的闭环系统鲁棒二次稳定并且当执行器出现故障时不确定广义系统仍能保持鲁棒二次稳定的充分条件,即不确定广义系统具有完整性的充分条件,最后用数学例子说明本方法的有效性.

参数不确定的广义T-S模糊系统的鲁棒容错保性能控制

研究了参数不确定并且部分执行器可能失效的广义T S模糊系统鲁棒容错保性能控制问题·对于所容许的不确定参数,给出了鲁棒容错保性能控制器存在的充分条件·在此条件下所设计的控制器,不仅使闭环系统渐近稳定而且具有适当的性能指标·通过矩阵分解把广义系统的非严格矩阵不等式约束转化为严格矩阵不等式,克服了广义系统不能直接利用LMI工具箱的弱点,从而和正常系统一样,可以直接使用LMI工具箱求解控制器·算例说明了所给方法的可行性和有效性·

不确定广义系统动态输出反馈鲁棒H_∞控制器设计

在 E确定其他系数矩阵均存在不确定性情况下 ,基于线性矩阵不等式给出系统的动态输出反馈鲁棒 H∞ 控制器设计方法。所得的控制律保证闭环系统对所有允许的不确定性是正则、稳定、无脉冲的且满足给定的 H∞ 性能指标。算例说明了该控制器设计方法的有效性。

广义不确定周期时变系统的鲁棒镇定控制

通过广义周期时变系统Lyapunov不等式和广义不确定周期时变系统鲁棒稳定的充分必要条件,讨论了在状态反馈控制下闭环系统的鲁棒镇定问题,得到了系统鲁棒镇定的充分必要条件,且给出了一族状态反馈鲁棒镇定器的设计方法;提出了广义周期时变系统二次稳定的概念,并讨论了二次稳定与鲁棒镇定的关系,得到了广义不确定周期时变系统二次稳定的充分必要条件.最后,通过数值算例说明了主要结果.

参数不确定性广义周期时变系统的鲁棒稳定性分析

基于广义周期时变系统允许的充分必要条件,提出了参数不确定性广义周期时变系统鲁棒稳定的概念,并得到了该类系统鲁棒稳定的充分必要条件.研究在状态反馈控制下保证闭环系统鲁棒稳定的条件,给出了一族状态反馈鲁棒稳定器的设计方法.引入广义周期时变系统二次稳定的概念,讨论了二次稳定性与鲁棒稳定性的关系.最后通过数值算例说明了所得的主要结果.