Stability Analysis and Antiwindup Design of Switched Linear Systems with Actuator Saturation

International Journal of Control, Automation and Systems - This paper investigates the stability analysis and anti-windup design problem for a class of switched linear systems with input saturation...     

Stability of Switched Positive Linear Systems with Actuator Saturation under Mode-dependent Average Dwell Time

The stability problem is investigated for switched positive linear systems (SPLS) with unstabilized subsystem and actuator saturation. By using Lyapunov functions method and mode-dependent average dwell time (MDADT) strategy, sufficient conditions of the stability for the considered systems are established. We also give an estimate of the attraction domain. The convex hull represent approach is used to deal with actuator saturation. Finally, two examples are carried out to show the validity of results, which is less conservative than the average dwell time (ADT) switching.

     

线性开关系统的饱和控制

利用开关系统切换的特点研究了线性开关系统的饱和控制问题,在较弱的条件下,得到了开关系统饱和镇定的结果,即构成开关系统的每个子系统可以是非稳定的,但假定由开关系统构成的某个凸组合系统是可稳的.借助于Lyapunov函数设计饱和控制器,基于凸组合系统的稳定性设计切换规律,引入设计参数满足控制器实现的条件,使开关系统局部渐近稳定.     

Event-triggered Control of Positive Switched Systems with Actuator Saturation and Time-delay

Machine Intelligence Research - This paper investigates the event-triggered control of positive switched systems with randomly occurring actuator saturation and time-delay, where the actuator...     

Output Feedback Stabilization of Linear Systems With Actuator Saturation

The note presents a method for designing an output feedback law that stabilizes a linear system subject to actuator saturation with a large domain of attraction. This method applies to general linear systems including strictly unstable ones. A nonlinear output feedback controller is first expressed in the form of a quasi-LPV system. Conditions under which the closed-loop system is locally asymptotically stable are then established in terms of the coefficient matrices of the controller. The design of the controller (coefficient matrices) that maximizes an estimate of the domain of attraction is then formulated and solved as an optimization problem with LMI constraints     

具有执行器饱和的切换2-D系统事件触发控制

针对具有执行器饱和的切换2-D连续离散系统,提出了一种基于多Lyapunov函数法的事件触发控制方案。为了减少通信资源浪费和执行器的损耗,提出了一种事件触发机制。该触发机制考虑了执行器饱和特性,只有当执行器未饱和,且满足事件触发条件时,控制器才会更新。利用凸组合技术和多Lyapunov函数法,提出了一种状态依赖的切换信号与状态反馈控制器的设计方法,并对闭环系统的指数稳定性进行了分析,利用线性矩阵不等式技术导出了控制器增益矩阵存在的充分条件。利用Darboux方程的仿真算例验证了所提出的事件触发控制方案的有效性,仿真结果表明了在所设计的控制方案下,闭环系统的状态是指数收敛的,同时还能减少通信资源的浪费。     

PID Control of Planar Nonlinear Uncertain Systems in the Presence of Actuator Saturation

This paper investigates PID control design for a class of planar nonlinear uncertain systems in the presence of actuator saturation.Based on the bounds on the growth rates of the nonlinear uncertain function in the system model,the system is placed in a linear differential inclusion.Each vertex system of the linear differential inclusion is a linear system subject to actuator saturation.By placing the saturated PID control into a convex hull formed by the PID controller and an auxiliary linear feedback law,we establish conditions under which an ellipsoid is contractively invariant and hence is an estimate of the domain of attraction of the equilibrium point of the closed-loop system.The equilibrium point corresponds to the desired set point for the system output.Thus,the location of the equilibrium point and the size of the domain of attraction determine,respectively,the set point that the output can achieve and the range of initial conditions from which this set point can be reached.Based on these conditions,the feasible set points can be determined and the design of the PID control law that stabilizes the nonlinear uncertain system at a feasible set point with a large domain of attraction can then be formulated and solved as a constrained optimization problem with constraints in the form of linear matrix inequalities(LMIs).Application of the proposed design to a magnetic suspension system illustrates the design process and the performance of the resulting PID control law.     

Set Invariance Conditions for Singular Linear Systems Subject to Actuator Saturation

In this note, we establish a set of conditions under which an ellipsoid is contractively invariant with respect to a singular linear system under a saturated linear feedback. These conditions can be expressed in terms of linear matrix inequalities, and the largest contractively invariant ellipsoid can be determined by solving an optimization problem with LMI constraints. With the feedback gain viewed as an additional variable, this optimization problem can be readily adapted for the design of feedback gain that results in the largest contractively invariant ellipsoid. Moreover, in the degenerate case where the singular linear system reduces to a regular system, our set invariance conditions reduce to the existing set invariance conditions for normal linear systems.     

大规模离散线性系统的分散饱和反馈镇定(英文)

考虑了具有执行器饱和的大规模离散时间线性系统分散控制器的设计.首先进行了在执行器幅值饱和的情形下的研究,然后延伸到执行器具有多层饱和的情况,例如,幅值和速率同时存在饱和或通过多层神经元网络近似的执行器非线性.在这2种情况下,给出了闭环系统在分散状态反馈律的作用下,椭球收敛不变性的条件.基于这些条件,可取得大吸引域的分散状态反馈控制律的设计可以归结为具有双线性矩阵不等式(BMI)约束的优化问题.对这些双线性约束优化问题提出了数值算法.数值算例显示了所提出的设计方法的有效性.     

Stabilization and H∞ Control of Nonlinear Switched Hamiltonian Systems Subject to Actuator Saturation

This paper investigates the stabilization and H_∞ control problem of nonlinear switched Hamiltonian systems (NSHSs) subject to actuator saturation (AS) under arbitrary switching paths. First, based on the saturating actuator property, an appropriate state feedback is designed under a realistic assumption for the stabilization of NSHSs with AS. Then, an H_∞ controller is designed for NSHSs subject to AS with external disturbances in order to attenuate the disturbances. Futhermore, the results obtained for NSHSs are applied to study the stabilization and H_∞ control of switched nonlinear systems with AS via the Hamiltonian realization method. Finally, simulation examples show the efficiency of the methods and results proposed in this paper.     

Analysis and Design of Time-Delay Impulsive Systems Subject to Actuator Saturation

This paper investigates the exponential stability and performance analysis of nonlinear time-delay impulsive systems subject to actuator saturation. When continuous dynamics is unstable, under some conditions, it is shown that the system can be stabilized by a class of saturated delayed-impulses regardless of the length of input delays. Conversely, when the system is originally stable, it is shown that under some conditions, the system is robust with respect to sufficient small delayed-impulses....     

Accessibility of Switched Linear Systems

This note considers the controllability of switched linear systems. The structure of accessibility Lie algebra is revealed. Some accessibility properties are proved. Certain necessary and sufficient conditions for (local or global, weak or normal) controllability of a large class of switched linear systems are obtained.     

Stability Analysis and Design of Uncertain Discrete‐time Switched Systems with Actuator Saturation Using Antiwindup and Multiple Lyapunov Functions Approach

The stability analysis and anti‐windup design problem is investigated for a class of discrete‐time switched systems with saturating actuators by using the multiple Lyapunov functions approach. Firstly, we suppose that a set of linear dynamic output controllers have been designed to stabilize the switched system without input saturation. Then, we design anti‐windup compensation gains and a switching law in order to enlarge the domain of attraction of the closed‐loop system. Finally, the anti‐windup compensation gains and the estimation of domain of attraction are presented by solving a convex optimization problem with linear matrix inequality (LMI) constraints. A numerical example is given to demonstrate the effectiveness of the proposed design method.     

执行器饱和的线性连续系统的镇定

针对控制系统中广泛存在饱和问题,主要研究执行器饱和线性连续系统的镇定问题并进行吸引域估计。首先根据Finsler’s引理和Lyapunov函数方法研究系统稳定的充分条件,得到执行器饱和控制系统稳定的新判据。其次,在稳定条件下,应用凸组合方法和新引入的自由权矩阵使得系统吸引域估计具有更小的保守性,将所得非线性矩阵不等式转化为线性矩阵不等式,给出求解最大吸引域的优化方法和状态反馈控制器的设计方案。最后通过仿真算例验证结果的有效性和可行性。     

参数不确定切换系统饱和控制器的随机梯度求解方法

针对一类各子系统执行机构均具有饱和特性的参数不确定线性切换系统,首先基于公共李雅普诺夫函数法给出了任意序列下稳定的状态反馈控制器设计方法,而后构造出用于求解饱和控制律的随机梯度算法．该算法依概率可收敛到一组可行解,数值例子表明了该算法的有效性．     

On Controllability of Switched Linear Systems

This paper investigates the number of switchings and design of switching sequences for controllability of switched linear systems. Two related results are established. One is a new constructive approach to designing switching sequences. The controllable state set of each switching sequence designed via the approach coincides with the controllable subspace of switched linear systems. The other is a well-estimated value for the minimum number of switchings required for controllability. Each state in the controllable subspace can be steered to origin within this value of switching times.     

一类执行器幅值与速率受限的线性系统静态抗饱和综合

讨论一类线性约束系统的静态抗饱和综合问题, 将执行器动力学特性引入增广系统, 从而化原系统为仅有幅值饱和的高阶增广系统. 提出基于线性矩阵不等式(LMI)的优化算法, 求得的静态抗饱和增益同时保证闭环系统的局部稳定性与最小化的L2增益. 仿真算例验证了方法的有效性.     

On the Stability of Switched Positive Linear Systems

It was recently conjectured that the Hurwitz stability of the convex hull of a set of Metzler matrices is a necessary and sufficient condition for the asymptotic stability of the associated switched linear system under arbitrary switching. In this note, we show that (1) this conjecture is true for systems constructed from a pair of second-order Metzler matrices; (2) the conjecture is true for systems constructed from an arbitrary finite number of second-order Metzler matrices; and (3) the conjecture is in general false for higher order systems. The implications of our results, both for the design of switched positive linear systems, and for research directions that arise as a result of our work, are discussed toward the end of the note.     

时变线性切换系统的指数镇定

研究满足驻留时间条件的时变线性切换系统的指数镇定问题.在一致完全可控条件下,引入带权可控性格拉姆矩阵设计出参数化的反馈控制器,利用比较原理给出状态转移矩阵的超调估计.针对驻留时间已知和未知两种情况,通过选择设计参数消除切换产生的超调影响,建立了两个指数镇定结论.最后以仿真实例验证本文结论.