基于输出反馈的一类大型互联非线性系统的鲁棒全局实际镇定

本文研究基于输出反馈的一类大型互联非线性不确定系统的鲁棒全局实际镇定问题,该系统的非线性互联项满足小于一次的增长性条件,通过构造每个子系统收敛的状态观测器,并对观测器的状态作线性变换,得到鲁棒分散输出反馈控制器.当输出反馈控制律作用于该系统时,闭环系统是全局实际稳定的.     

基于输出反馈的一类大型互联Holder非线性系统的全局实际镇定

本文研究基于输出反馈的一类大型互联Holder连续非线性系统的全局实际镇定问题.通过构造每个子系统的状态观测器,并对观测器的状态作线性变换,得到分散输出反馈控制器.当输出反馈控制律作用于该系统时,闭环系统是全局实际稳定的.     

具有输入时滞的汽车主动悬架系统的鲁棒指数镇定

针对具有输入时滞及控制量和输出约束的汽车主动悬架不确定系统,研究了鲁棒H_∞指数镇定问题.通过设计状态反馈控制器,使得闭环系统鲁棒指数稳定,并且能够有效地抑制外界干扰.通过实例仿真验证了所设计控制器的有效性和可行性.     

基于状态观测器的不确定时滞系统H_∞鲁棒容错控制

针对一类具有状态时滞的不确定线性系统,详细阐述了该系统基于状态观测器的H_∞鲁棒容错控制问题.当系统状态不可测时,构造状态观测器,并考虑状态观测器反馈回路传感器失效,引入观测误差,通过构造闭环增广系统的Lyapunov泛函,设计出了有容错性能的状态观测器和基于该观测器的状态反馈控制器,使得闭环增广系统渐近稳定,并满足H_∞性能指标.通过求解一个线性矩阵不等式就可同时得到观测器增益和控制器增益矩阵.最后给出仿真算例,验证了此方法的有效性.     

一类非最小相位非线性系统的鲁棒输出调节

研究了一类具有非最小相位和非线性外部系统的非线性系统的全局鲁棒输出调节问题.首先,利用浸入系统设计了一个非线性内模.其次,把原系统的全局鲁棒输出调节问题转化为增广系统的全局鲁棒镇定问题.然后,利用改变能量函数和动态增益技巧设计了一个状态反馈控制器,使得闭环系统的解有界并且跟踪误差渐近趋于零.最后,利用仿真结果验证了所设计的控制器的有效性.     

广义线性系统基于PI观测器鲁棒极点配置分离原理

对广义线性系统提出了基于全维比例-积分观测器的控制系统设计的鲁棒极点配置分离原理.基于矩阵灵敏度理论证明了如下事实：与状态反馈系统相同的闭环系统极点具有和状态反馈系统极点相同的极点灵敏度,与观测器系统相同的闭环系统.极点具有和观测器系统极点相同的极点灵敏度.于是基于全维PI观测器的状态反馈控制器的具有最小灵敏度的鲁棒极点配置可以通过求解两个分开的鲁棒状态反馈极点配置问题实现.     

不确定离散模糊随机系统的鲁棒方差约束输出反馈控制

对一类具有范数有界不确定性的离散T-S模糊随机系统。研究不仅使整个闭环模糊系统全局渐近稳定。而且每个模糊子系统的稳态状态方差满足给定上界性能指标约束的输出反馈鲁棒方差控制律的设计问题。利用线性矩阵不等式(LMI)技术，导出输出反馈鲁棒方差控制律的存在条件，并基于矩阵相似变换给出其可解性条件，同时用一组线性矩阵不等式的可行解。给出输出反馈鲁棒方差控制律的一个参数化表达形式。     

基于输出反馈的一类时滞系统鲁棒H∞容错控制

针对状态具有多个时滞的线性不确定性系统,基于李雅普诺夫稳定性理论,矩阵不等式及线性矩阵不等式方法,设计带有多个时滞记忆的输出反馈鲁棒H∞容错控制器.研究了在执行器发生故障的情况下,多时滞不确定性系统的鲁棒H∞容错控制的问题.首先给出了多个时滞记忆的输出反馈鲁棒H∞容错控制器的综合分析,进一步给出参数不确定项的多时滞系统的渐近稳定的充分条件,以及满足给定性能指标鲁棒H∞容错控制器的设计方法.仿真结果证明了该方法的有效性和可行性.     

分布时滞系统的动态输出反馈鲁棒稳定

主要研究了一类具分布时变时滞不确定系统的输出反馈鲁棒稳定问题.基于动态输出反馈和Lyapunov-Krasovskii泛函,给出了闭环系统与时滞相关的鲁棒稳定的条件.所得条件为线性矩阵不等式形式,便于运用内点算法进行求解.     

基于LMI方法的一类非线性模糊脉冲系统的鲁棒模糊控制

通过推广一般T-S模糊模型定义了一类非线性模糊脉冲系统.基于线性矩阵不等式(LMI)方法提出了一种鲁棒模糊控制新方案.采用并行分布补偿(PDC)的基本思想设计状态反馈控制器,并利用Lyapunov方法理论证明闭环系统全局指数稳定.最后基于LMI方法,将鲁棒模糊控制器的设计问题转化为线性矩阵不等式问题(LMIP).仿真表明本方法的有效性.     

A counterexample for the global separation principle for discrete-time nonlinear systems

In the control systems literature, it is well known that a separation principle holds locally for nonlinear control systems, when exponential feedback stabilizers and exponential observers are used. In this paper, we present a counterexample to show that the global separation principle need not hold for nonlinear control systems. Our example demonstrates that global stability might be lost when an exponential observer is introduced into the nonlinear feedback loop associated with an exponentially stabilizing feedback control law.     

Output feedback vibration control of a string driven by a nonlinear actuator

In this paper, we design an observer-based output feedback controller to exponentially stabilize a system of nonlinear ordinary differential equation-wave partial differential equation-ordinary differential equation. An observer is designed to estimate the full states of the system using available boundary values of the partial differential equation. The output feedback controller is built via the combination of the ordinary differential equation backstepping which is applied to deal with the nonlinear ordinary differential equation, and the partial differential equation backstepping which is used for the wave partial differential equation-ordinary differential equation. The controller can be applied into vibration suppression of a string-payload system driven by an actuator with nonlinear characteristics. The global exponential stability of all states in the closed-loop system is proved by Lyapunov analysis. The numerical simulation illustrates the states of the actuator, string, payload and the observer errors are fast convergent to zero under the proposed output feedback controller.     

A relation between the output regulation and the observer design for nonlinear systems

Output regulation and observer design are two important problems for nonlinear systems, and there is a vast literature addressing each problem separately in the control literature. Isidori and Byrnes [1] have solved the output regulation problem for nonlinear systems with a Poisson stable exosystem, and Sundarapandian [2] has solved the exponential observer design problem for Lyapunov stable nonlinear systems. In this paper, we demonstrate that for a special class of Lyapunov stable nonlinear systems, namely neutrally stable systems, the exponential observer design problem can be solved by converting it into an output regulation problem and then solving the new problem using the output regulation techniques of Isidori and Byrnes [1]. Finally, we present the corresponding results for the discrete-time case.     

基于输出反馈的一类非线性不确定互联大系统的分散H∞控制

本文研究基于输出反馈的一类大型互联非线性不确定系统的分散H∞控制问题,通过构造每个子系统收敛的状态观测器,得到分散输出反馈控制器.当反馈控制律作用于该系统时,无扰动输入的闭环系统是全局渐近稳定的,而对允许的不确定性,干扰抑制的大小可以任意小,且控制器的设计也无需解任何的Hamilton-Jacobi方程或不等式.     

一类离散系统基于偏差分离的输出反馈控制

针对一类不确定离散系统,提出一种基于偏差分离的输出反馈双控制策略,首先设计动态输出反馈控制器镇定其标称系统(即不确定性为零的情形);然后通过构造降维观测器,在线获取不确定性信息,并采用线性的补偿器实时补偿系统的不确定性.该控制策略采用线性控制,在工程中可以方便地实现,具有好的工程意义.理论分析证明了闭环指数渐近稳定的充分条件.仿真结果表明该双控制策略的有效性.     

Semi-global finite-time output feedback stabilization for a class of large-scale uncertain nonlinear systems

This paper addresses the problem of semi-global finite-time decentralized output feedback control for large-scale systems with both higher-order and lower-order terms. A new design scheme is developed by coupling the finite-time output feedback stabilization method with the homogeneous domination approach. Specifically, we first design a homogeneous observer and an output feedback control law for each nominal subsystem without the nonlinearities. Then, based on the homogeneous domination approach, we relax the linear growth condition to a polynomial one and construct decentralized controllers to render the nonlinear system semi-globally finite-time stable.     

Design of a continuous-discrete observer for state affine systems

In many engineering control problems, the output measurements are discrete-time ones. In this paper, we show how we can design an observer synthesis for continuous-time affine systems using discrete time output measurements.In fact, we give sufficient conditions on both output sampling time and system input, which allow us to preserve the observability of the system and to design an exponential observer.     

基于观测器的模糊时滞系统指数稳定的一种设计方法

研究了一类模糊时滞系统的指数稳定问题.首先利用T-S模型对非线性不确定性时滞系统进行建模,在此基础上设计了基于观测器的模糊状态反馈控制器,通过巧妙选取Lyapunov函数给出了模糊闭环时滞系统的条件及稳定裕度且模糊反馈增益和模糊观测器增益可通过求解线性矩阵不等式获得.     

Adaptive output feedback asymptotic stabilization of nonholonomic systems with uncertainties

A global adaptive output feedback control strategy is presented for a class of nonholonomic systems in generalized chained form with drift nonlinearity and unknown virtual control parameters. The purpose is to design a nonlinear output feedback switching controller such that the closed-loop system is globally asymptotically stable. By using the input-state scaling technique and an integrator back-stepping approach, an output feedback controller is given. A filter of observer gain is introduced for state and parameter estimates. Meanwhile, in order to avoid the over-parameters, a tuning function technique is utilized. A novel switching control strategy based on the output measurement of the first subsystem rather than time is used to overcome the uncontrollability of the x₀-subsystem in the origin. The proposed controller can guarantee that all the system states globally converge to the origin, while other signals maintain bounded. The numerical simulation testifies the effectiveness.