Robust H_∞ and H_2 Static Output Feedback Control of Discrete-time Piecewise Affine Singular Systems with Norm-bounded Uncertainties

This paper is concerned with the problem of designing robust H∞and H2static output feedback controllers for a class of discrete-time piecewise-affine singular systems with norm-bounded time-varying parameters uncertainties. Based on a piecewise singular Lyapunov function combined with S-procedure,Projection lemma and some matrix inequality convexifying techniques,sufficient conditions in terms of linear matrix inequalities are given for the existence of an output-feedback controller for the discrete-time piecewiseaffine singular systems with a prescribed H∞disturbance attenuation level,and the H2norm is smaller than a given positive number. It is shown that the controller gains can be obtained by solving a family of LMIs parameterized by one or two scalar variables. The numerical examples are given to illustrate the effectiveness of the proposed design methods.

Observer-based H-infinity output feedback control with feedback gain and observer gain variations for Delta operator system

Considering that the controller feedback gain and the observer gain are of additive norm-bounded variations, a design method of observer-based H-infinity output feedback controller for uncertain Delta operator systems is proposed in this paper. A sufficient condition of such controllers is presented in linear matrix inequality （LMI） forms. A numerical example is then given to illustrate the effectiveness of this method, that is, the obtained controller guarantees the closed-loop system asymptotically stable and the expected H-infinity performance even if the controller feedback gain and the observer gain are varied.

Robust output-feedback stabilization of a class of nonlinear systems with the nonlinearities of varied form

The back-stepping designs based on confine functions are suggested for the robust output-feedback global stabilization of a class of nonlinear continuous systems; the proposed stabilizer is efficient for the nonlinear continuous systems confined by a bound function, the nonlinearities of the systems may be of varied forms or uncertain; the designed stabilizer is robust means that a class of nonlinear continuous systems can be stabilized by the same output feedback stabilization schemes; numerical simulation examples are given.

Output Feedback Controller Design for Discrete-time Switched Singular Systems

This paper is concerned with the problems of robust admissibility and static output feedback( SOF)stabilization for a class of discrete-time switched singular systems with norm-bounded parametric uncertainties.The objective is to design a suitable robust SOF controller guaranteeing the regularity,causality and asymptotic stability of the resulting closed-loop system under arbitrary switching laws. Based on the basic matrix inequality sufficient condition for checking the admissibility of switched singular systems,together with some matrix inequality convexifying techniques,the SOF controller synthesis is developed for the underlying systems. It is shown that the controller gains can be obtained by solving a set of strict linear matrix inequalities( LMIs). A simulation example is given to show the effectiveness of the proposed method.

Output Feedback Nonlinear General Integral Control

This paper proposes an output feedback nonlinear general integral controller for a class of uncertain nonlinear system. By solving Lyapunov equation, we demonstrate a new proposition on Equal ratio gain technique. By using Equal ratio gain technique, Singular perturbation technique and Lyapunov method, theorem to ensure regionally as well as semi-globally exponential stability is established in terms of some bounded information. Moreover, a real time method to evaluate the ratio coefficients of controller and observer are proposed such that their values can be chosen moderately. Theoretical analysis and simulation results show that not only output feedback nonlinear general integral control has the striking robustness but also the organic combination of Equal ratio gain technique and Singular perturbation technique constitutes a powerful tool to solve the output feedback control design problem of dynamics with the nonlinear and uncertain actions.

Robust H_∞ control for aseismic structures with uncertainties in model parameters

This paper presents a robust H∞ output feedback control approach for structural systems with uncertainties in model parameters by using available acceleration measurements and proposes conditions for the existence of such a robust output feedback controller. The uncertainties of structural stiffness, damping and mass parameters are assumed to be norm-bounded. The proposed control approach is formulated within the framework of linear matrix inequalities, for which existing convex optimization techniques, such as the LM1 toolbox in MATLAB, can be used effectively and conveniently. To illustrate the effectiveness of the proposed robust H∞ strategy, a six-story building was subjected both to the 1940 E1 Centro earthquake record and to a suddenly applied Kanai-Tajimi filtered white noise random excitation. The results show that the proposed robust H∞ controller provides satisfactory results with or without variation of the structural stiffness, damping and mass parameters.

General Integral Control Design via Feedback Linearization

Based on the feedback linearization technique, we present a systematic design method for the General Integral Control and a new integral control strategy along with a class of fire-new integrator. By using the linear system theory and Lyapunov method along with LaSalle’s invariance principle, the conditions on the control gains to ensure regionally as well as semi-globally asymptotic stability are provided. Theoretical analysis and simulation results demonstrated that: by using this design method, General Integral Control can deal with nonlinearity and uncertainties of dynamics more effectively;the optimum response can be achieved in the whole control domain, even under uncertain payload and varying-time disturbances. This means that General Integral Control has strong robustness, fast convergence, good flexibility, and then makes the engineers design a high performance controller more easily.

Robust Admissibility and Stabilization of Uncertain Singular Fractional-Order Linear Time-Invariant Systems

This paper addresses the robust admissibility problem in singular fractional-order continuous time systems. It is based on new admissibility conditions of singular fractional-order systems expressed in a set of strict linear matrix inequalities(LMIs). Then, a static output feedback controller is designed for the uncertain closed-loop system to be admissible. Numerical examples are given to illustrate the proposed methods.

Lipschitz非线性离散系统基于观测器的鲁棒镇定控制设计

本文研究Lipschitz非线性离散时间系统的基于观测器的鲁棒镇定控制问题.首先,针对Lipschitz非线性离散系统,应用微分中值定理和线性参变系统理论,以线性矩阵不等式(LMI)的形式给出基于观测器的鲁棒镇定控制设计的充分条件.随后,将设计结果进一步推广,针对含干扰的Lipschitz非线性离散系统进行H∞性能分析,实现了基于观测器的鲁棒H∞镇定控制,同时给出观测器增益矩阵和控制器增益矩阵的一步求解算法.最后,通过两个数值例子验证了所提方法的有效性.

基于动态观测器的不确定机器人鲁棒控制研究

针对仅有精确位置测量的机器人系统 ,在系统参数不确定和有界干扰并存的情况下 ,提出一种基于速度观测的鲁棒控制方案。在滑模观测器设计中引入补偿项 ,动态抵消系统偏差对速度重构的影响 ,确保观测误差指数收敛到有界域。采用Lyapunov直接法设计基于标称模型和观测速度的鲁棒控制律 ,使系统闭环满足局部一致最终有界收敛。

一类不确定非线性系统的鲁棒输出反馈控制

本文考虑一类具有输出反馈标准形的非线性系统的输出反馈控制问题．为了给出其不同于自适应控制的解决办法，设计出了新的鲁棒输出反馈控制方案。该方案不需辨识系统未知参数，也不需知道未知参数向量的上界，就能保证所有控制系统信号的全局有界性．并且通过控制器参数的适当选择，可以使系统跟踪误差达到任意小．仿真结果表明可以获得良好的跟踪效果．

不确定长时延网络控制系统的H_∞鲁棒控制

在状态不完全可测的网络控制系统中,针对不确定网络长时延、网络噪声等问题系统性能造成的影响,研究了一类具有不确定长时延网络控制系统的H∞鲁棒控制问题。在不确定网络时延大于一个采样周期时,将采用动态输出反馈的网络控制系统建模为一类具有参数不确定性的线性离散系统。基于Lyapunov稳定性理论和线性矩阵不等式(LMI)方法,导出了闭环系统渐近稳定且满足给定H∞性能指标的充分条件,并给出了输出反馈控制器的设计方法。通过仿真算例证明了该方法的有效性。

约束时变不确定离散系统的输出反馈预测控制综合

研究多包描述系统的离线型输出反馈预测控制.已有一方法首先综合状态反馈预测控制,满足输入/状态约束;而在设计观测器时,不再考虑输入/状态约束.本文则首先给出观测器,并给出一组不等式条件使得真实状态、观测状态和观测误差都保持在同一个椭圆内部,以便采用线性矩阵不等式处理输入/状态约束.基此,本文离线计算一椭圆序列,每个椭圆对应一控制律和一观测器,而在线的实时控制律和观测器则从该序列中选择,使得闭环系统具有稳定性保证.仿真例子说明了本文方法的有效性.

非线性系统的输出反馈鲁棒H^∞控制

考虑一类带模有界时变不确定的非线性系统鲁棒Ｈ∞控制问题．讨论其带内部稳定的状态反馈及输出反馈鲁棒Ｈ∞控制问题可解的充分条件．结果表明，带模有界结构的时变不确定非线性系统，其鲁棒Ｈ∞控制问题可以转化为一确定的非线性系统的Ｈ∞控制来解决，从而可由－Ｈａｍｉｌｔｏｎ－Ｊａｃｏｂｉ－Ｉｓａａｃｓ微分不等式的可解性来讨论．

考虑参数不确定性的汽车前轮主动转向输出反馈鲁棒控制

提出基于静态输出反馈的前轮主动转向(AFS)鲁棒控制器,以提高汽车横摆角速度跟踪性能和横向稳定性.在控制器设计中考虑了车速和轮胎侧偏刚度的不确定性,其中车速在一定范围内变化并且可测,采用多胞型模型来描述车速的不确定性.利用多目标优化与输出反馈鲁棒控制方法,同时提高汽车横摆角速度跟踪性能和横向稳定性.在Matlab/Simulink和Car Sim联合仿真环境中,对紧急转弯和双移线2种典型操纵工况下的控制器进行仿真试验.结果表明,所提出的控制器能够显著改善汽车的横向操纵性能和稳定性,降低驾驶员的工作负荷,且控制器对汽车模型参数的不确定性具有很好的鲁棒性.

基于LMI的线性时滞系统输出动态反馈镇定

考虑线性时滞系统的输出动态反馈镇定问题.利用自由参数矩阵对闭环系统进行适当变换,并结合相应的Lyapunov-Krasovskii泛函得到了时滞相关的控制器存在性判据.利用控制器参数化方法,将控制器参数与泛函参数的求解归结为线性矩阵不等式解的形式,从而克服了时滞无关性及求解非凸优化问题所导致的保守性.仿真算例验证了结论的有效性.

基于动态输出反馈的半车主动悬架系统鲁棒控制

研究了半车主动悬架系统基于输出反馈的干扰抑制鲁棒控制问题。首先建立了半车主动悬架系统的动力学模型,然后针对车体位置和速度、车身俯仰角度和角速度、前后车轮位置和速度无传感器测量情况下,系统中还存在非线性和外界扰动的现象,提出了一种动态输出反馈鲁棒干扰抑制控制策略。理论推导和仿真结果都证明了所设计控制器的正确性和有效性,通过和传统的PID控制算法相对比,进一步说明所设计的控制器能提高汽车的行驶平顺性和操作稳定性。

不确定时滞系统的输出反馈稳定化控制器设计

研究了一类具有时变参数不确定性的时滞系统输出反馈鲁棒镇定问题，证明了这样的问题可以转化成不带任何不确定性的线性时不变系统的Ｈ∞控制问题，从而应用现有Ｈ∞控制问题的求解方法得到不确定时滞系统的稳定化输出动态反馈控制器设计方法．