离散T-S模糊系统的部分状态反馈H∞控制

基于部分状态信息的控制器是一类特殊的静态输出反馈控制器,一般难以利用线性矩阵不等式工具求解.本文研究离散T-S模糊系统的部分状态反馈镇定及部分状态反馈H∞控制问题.通过引入松弛变量,将离散T-S模糊系统的部分状态反馈镇定问题转换成求解一组线性矩阵不等式（LMI）,并给出基于LMI的部分状态反馈H∞控制器设计方法.通过数值算例验证了所给方法的有效性.     

不确定广义模糊系统的鲁棒模糊H∞控制器设计

研究了不确定广义模糊系统鲁棒H∞状态反馈控制器和动态输出反馈控制器设计问题。在E确定其它系数矩阵均存在不确定性情况下，给出鲁棒模糊H∞状态反馈控制器和动态输出反馈控制器存在的充分条件。鲁棒H∞状态反馈控制律的设计可能通过求解线性矩阵不等式得到，而动态输出反馈鲁棒H∞控制器可通过定义新变量得到，所求控制器使闭环系统对所有的不确定性稳定且满足H∞性能指标γ。     

基于LM I 的一类非线性时滞关联大系统的分散模糊控制

针对一类采用Takagi—Sugeno模糊模型描述的非线性时滞关联大系统，研究其分散模糊状态反馈控制器设计问题；利用Lyapunov稳定性分析理论和线性矩阵不等式等工具，得到了闭环系统的可镇定条件和相应的分散模糊状态反馈控制器；在此基础上，通过求解具有线性矩阵不等式组约束的凸优化问题，给出了具有较小反馈增益的分散模糊控制器设计方法。     

不确定关联大系统分散鲁棒H∞输出反馈控制

针对一类状态矩阵和控制矩阵存在参数不确定性关联大系统,研究其分散鲁棒H∞输出反馈控制问题.基于有界实引理将其鲁棒分散H∞动态输出反馈控制器的解归结为一个非线性矩阵不等式(NLMI),先通过选取适当的同伦函数来表示该非线性矩阵不等式,再通过Schur补引理将其化为两个双线性矩阵不等式,最后通过迭代算法求解该控制器,使闭环大系统鲁棒渐进稳定,并且满足给定的H∞性能指标.     

模糊奇异摄动系统及其稳定性分析与综合

通过扩展常规Takagi-Sugeno模糊系统,定义了一类模糊奇异摄动系统,利用矩阵不等 式表达出了在摄动参数足够小时的闭环稳定性.镇定并行分布式补偿控制器增益和共同的Lyapunov 函数可利用两步法得到,并可分别归结于一组线性矩阵不等式和双线性矩阵不等式,后者 可以利用迭代线性矩阵不等式方法有效地求解.文末给出了数值和仿真实例.     

基于迭代线性矩阵不等式的奇异摄动系统同时镇定

研究了采用一个线性状态反馈控制器镇定多个线性奇异摄动系统的问题.同时镇定条 件可以表达为一组矩阵不等式条件,所得条件与摄动参数无关,从而有效地回避了病态问题.采 用基于快慢分解的两步法可以得到镇定控制器增益和相应的Lyapunov函数.而在每一步需要利 用迭代线性矩阵不等式技术求解相应的双线性矩阵不等式,相关定理研究了算法的收敛性.本文 所得结论可同时适用于标准与非标准奇异摄动系统.文末给出了相应的仿真算例.     

基于矩阵测度的非线性广义时滞系统鲁棒模糊控制

研究T-S模糊广义时滞系统的鲁棒控制问题.不同于传统的寻求公共正定矩阵的方法,基于矩阵测度给出保证系统鲁棒稳定的充分条件,并将此条件进一步转化为线性矩阵不等式.通过求解线性矩阵不等式,得到状态反馈控制器和静态输出反馈控制器.最后通过算例仿真验证了方法的有效性.     

离散系统输出反馈H∞控制

研究了离散控制系统输出反馈H∞控制问题,已有方法对于控制系统系数矩阵要求十分严格,给出了采用输出反馈控制的新的控制器设计方法.经由相关的引理,针对不同的离散控制系统得出三个定理,将已有的输出反馈H∞控制的双线性矩阵不等式条件转换为一个线性矩阵不等式条件.可以充分利用线性矩阵不等式凸优化技术解决,输出反馈控制器设计提供更大的可行性,并且对于系统的系数矩阵要求有所降低,在一定程度上放松了已有结果的保守性.同时也说明了方法具有更大的应用范围.最后,一个仿真实例说明了算法的有效性.     

一类不确定多输入模糊双线性系统的鲁棒H∞控制

针对一类带有参数不确定性和干扰的多输入模糊双线性系统(FBS)的鲁棒H_∞控制问题,使用并行分布补偿算法(PDC)设计了模糊控制器,得到了整个模糊控制系统鲁棒全局稳定的充分条件,控制器的设计可以通过求解一系列线性矩阵不等式(LMI)获得.仿真例子验证了方法的有效性.     

1

本文研究了用Lur'e多非线性系统描述的被控对象的镇定问题.把问题的可解性归结到特殊的多线性矩阵不等式的可解性.非线性状态反馈和输出反馈控制器的设计分别依赖于一个双线性和三个三线性矩阵不等式的解.给出了基于线性矩阵不等式的交替寻优算法的设计步骤.     

Output feedback optimal guaranteed cost control of uncertain piecewise linear systems

This paper proposes the output feedback optimal guaranteed cost controller design method for uncertain piecewise linear systems based on the piecewise quadratic Lyapunov functions technique. By constructing piecewise quadratic Lyapunov functions for the closed‐loop augmented systems, the existence of the guaranteed cost controller for closed‐loop uncertain piecewise linear systems is cast as the feasibility of a set of bilinear matrix inequalities (BMIs). Some of the variables in BMIs are set to be searched by genetic algorithm (GA), then for a given chromosome corresponding to the variables in BMIs, the BMIs turn to be linear matrix inequalities (LMIs), and the corresponding non‐convex optimization problem, which minimizes the upper bound on cost function, reduces to a semidefinite programming (SDP) which is convex and can be solved numerically efficiently with the available software. Thus, the output feedback optimal guaranteed cost controller can be obtained by solving the non‐convex optimization problem using the mixed algorithm that combines GA and SDP. Numerical examples show the effectiveness of the proposed method. Copyright © 2008 John Wiley & Sons, Ltd.     

Robust PI controller design for nonlinear systems via fuzzymodeling approach

The design problem of proportional and proportional-plus-integral (PI) controllers for nonlinear systems is studied. First, the Takagi-Sugeno (T-S) fuzzy model with parameter uncertainties is used to approximate the nonlinear systems. Then a numerically tractable algorithm based on the technique of iterative linear matrix inequalities is developed to design a proportional (static output feedback) controller for the robust stabilization of the system in T-S fuzzy model. Next, we transform the problem of PI controller design to that of proportional controller design for an augmented system and thus bring the solution of the former problem into the configuration of the developed algorithm. Finally, the proposed method is applied to the design of robust stabilizing controllers for the excitation control of power systems. Simulation results show that the transient stability can be improved by using a fuzzy PI controller when large faults appear in the system, compared to the conventional PI controller designed by using linearization method around the steady state     

Fault-tolerant decentralized H-infinity control for multi-channel systems using homotopy method

This paper considers a fault-tolerant decentralized H-infinity control problem for multi-channel linear time-invariant systems. The purpose is to design a decentralized H-infinity output feedback controller to stabilize the given system and achieve a certain H-infinity performance requirement both in the normal situation and in the situation where any one of the local controllers fails. The designed problem is reduced to a feasibility problem of a set of bilinear matrix inequalities (BMIs). An algorithm is proposed to solve the BMIs. First, the normal situation is considered where all the local controllers are functioning. The local controllers are obtained from a standard centralized H-infinity controller by using a homotopy method imposing a structural constraint progressively. Secondly, the above case is extended to the one where any one of the local controllers fails. We again use a homotopy method where the coefficient matrices of the failed controller are decreased rogressively to zero. The efficiency of the proposed algorithm is demonstrated by an example.     

Fault-tolerant decentralized H-infinity control for multi-channel systems using homotopy method

This paper considers a fault-tolerant decentralized H-infinity control problem for multi-channel linear time-invariant systems. The purpose is to design a decentralized H-infinity output feedback controller to.stabilize the given system and achieve a certain H-infinity performance requirement both in the normal situation and in the situation where any one of the local controllers fails. The designed problem is reduced to a feasibility problem of a set of bilinear matrix inequalities （BMIs）. An algorithm is proposed to solve the BMIs. First, the normal situation is considered where all the local controllers are functioning. The local controllers are obtained from a standard centralized H-infinity controller by using a homotopy method imposing a structural constraint progressively. Secondly, the above case is extended to the one where any one of the local controllers fails. We again use a homotopy method where the coefficient matrices of the failed controller are decreased progressively to zero. The efficiency of the proposed algorithm is demonstrated by an example.     

H/sub /spl infin// controller synthesis of fuzzy dynamic systems based on piecewise Lyapunov functions and bilinear matrix inequalities

This work presents an H/sub /spl infin// controller design method for fuzzy dynamic systems based on techniques of piecewise smooth Lyapunov functions and bilinear matrix inequalities. It is shown that a piecewise continuous Lyapunov function can be used to establish the global stability with H/sub /spl infin// performance of the resulting closed-loop fuzzy control systems and the control laws can be obtained by solving a set of bilinear matrix inequalities (BMIs). Two examples are given to illustrate the application of the proposed methods.     

Output feedback controller design for uncertain piecewise linear systems

This paper proposes output feedback controller design methods for uncertain piecewise linear systems based on piecewise quadratic Lyapunov function. The α-stability of closed-loop systems is also considered. It is shown that the output feedback controller design procedure of uncertain piecewise linear systems with α-stability constraint can be cast as solving a set of bilinear matrix inequalities （BMIs）. The BMIs problem in this paper can be solved iteratively as a set of two convex optimization problems involving linear matrix inequalities （LMIs） which can be solved numerically efficiently. A numerical example shows the effectiveness of the proposed methods.     

State Feedback Control for Discrete‐time Markovian Jump Systems with Random Communication Time Delay

This paper concerns the stabilization problem for a class of networked control system with Markovian parameter using mode dependent state feed‐back controller through a wireless networked control system. The problem that the random network‐induced delays generated both by wireless connection contention and the movement of wireless nodes is taken into consideration. The mode dependent controller can be obtained by solving a set of parameterized bilinear matrix inequalities (BMIs). A numerical example is exhibited to show the effectiveness of the proposed design method.     

Improved L2 Gain Performance Controller Synthesis for Takagi–Sugeno Fuzzy System

In this paper, an improved L2 gain performance controller synthesis is proposed for Takagi-Sugeno (T-S) fuzzy system. The T-S fuzzy controller can be easily derived by a three-step procedure with the linear matrix inequalities (LMIs) technique. First, a new T-S fuzzy model structure is presented, which includes the original T-S fuzzy plant with stable pre- and post filters on the input and output of the original plant. Second, by using this structure the L2 gain performance controller design problem can be easily transformed into standard LMIs formulation. Compared with the previous results, it not only gives us a simple structure of the T-S fuzzy controller, but also provides us effective LMIs-based conditions, which include a small number of unknown matrix variables; consequently, less value of L2 gain performance of the closed-loop system can be obtained. Third, an augmented T-S fuzzy controller which guarantees L2 gain performance is obtained for the original T-S fuzzy plant, which is composed of the T-S controller derived from step two and two stable pre- and post filters. Finally, some numerical examples are demonstrated to show the effectiveness of the proposals.     

Quantized robust ℋ∞ control of discrete-time systems with random communication delays

The article considers stability and robust ?_∞ controller design of discrete-time systems with random communication delays and state quantization. A finite state Markov process is used to model communication delays between sensors and controllers. Measurements are assumed to be quantized by a logarithmic quantizer, and the effect of quantization errors are incorporated into the controller design. Based on a Lyapunov–Krasovskii approach, novel methodologies for analysing stability and designing a time-delay mode-dependent quantized state feedback controller are proposed. The controller is obtained through solving bilinear matrix inequalities (BMIs) using the cone complementarity linearisation algorithm.