严格正实线性多变量系统的鲁棒性分析及其输出反馈控制

讨论一类线性不确定系统的鲁棒严格正实分析和控制问题，其中各不确定参数矩阵具有线性分式形式，分析了这类系统对所有容许不确定性严格正实的条件，并综合了使闭环内稳且严格正实的动态输出反馈控制器，通过适当地构造增广系统，将这类问题转化为确定系统的严格正实分析和设计，并按增广系统给出了这类不确定系统鲁棒严格正实的充分必要条件以及动态输出反馈鲁棒严格正实控制器的存在条件。     

Dissipative control of linear discrete-time systems with dissipative uncertainty

This paper focuses on the dissipative control of uncertain linear discrete-time systems. The uncertainty under consideration is characterized by a dissipative system, which contains commonly used uncertainty structures, such as normbounded and positive real uncertainties, as special cases. We consider the design of a feedback controller which can achieve asymptotic stability and strict quadratic dissipativeness for all admissible uncertainties. Both the linear static state feedback and the dynamic output feedback controllers are considered. It is shown that the robust dissipative control problem can be solved in terms of a scaled quadratic dissipative control problem without uncertainty. Linear matrix inequality (LMI) based methods for designing robust controllers are derived. The result of this paper unifies existing results on discrete-time H and positive real control and it provides a more flexible and less conservative control design as it al ows for a bet er trade-off between phase and gain performances.     

Synthesis of positive real ℋ2 controllers

This paper describes a synthesis procedure for strictly positive real observer-based controllers. In particular, we address the standard ℋ₂-optimal control problem with the additional constraint on the strict positive realness of the controller. A suboptimal version of this problem is shown to be a convex optimization problem, and a linear matrix inequality-based solution is provided. One example illustrates the main results     

离散广义系统的鲁棒严格正实控制

研究确定的以及具有范数有界不确定性的离散广义系统的严格正实分析和控制问题,首先给出了确定离散广义系统状态反馈扩展严格正实控制器的存在条件和设计方法;然后利用线性矩阵不等式分析了不确定离散广义系统广义二次稳定且扩展严格正实的条件,讨论了状态反馈使闭环系统广义二次稳定且扩展严格正实问题,给出了状态反馈鲁棒扩展严格正实控制器的综合方法;最后通过数值算例说明了所提出方法的有效性．     

不确定广义系统的弹性H∞控制

研究了具有范数有界不确定性的广义系统的弹性H_∞控制问题. 首先证明了广义系统的有界实引理可以用一个严格的线性矩阵不等式来描述. 在此基础上, 针对控制器存在加性摄动的情形, 以严格线性矩阵不等式约束条件给出了弹性H_∞状态反馈控制器存在的充分必要条件, 并给出了控制器的显式表示. 算例验证了本文方法的可行性.     

Multi-periodic repetitive control system: a Lyapunov stability analysis for MIMO systems

A multi-input–multi-output (MIMO) repetitive control problem of tracking and disturbance rejection is considered when both reference and disturbance signals are finite linear combinations of periodic but not necessarily sinusoidal signals. Lyapunov stability analyses under a positive real condition (and a natural relaxation) and exponential stability under a strict positive real condition are provided together with bounds on the induced L ₂ and RMS gains of the closed loop system. It is shown that similar Lyapunov stability results apply when the plant is a positive real state-delay system. Extension of the analyses to a class of non-linear systems is discussed and indicates a good degree of robustness in the design.     

具有时变不确定线性系统的鲁棒无源控制

研究具有时变不确定参数的线性系统在有界能量外部输入作用下的鲁棒无源控制问题.目的是设计一个反馈控制器使得闭环系统是二次稳定,同时具有严格无源性.研究结果证明,这一问题可以转化为一个等价的具有某个参数的线性时不变系统的正实控制问题,从而可用现有的正实控制问题的求解方法解决所研究的问题.     

Dissipative analysis and control of state-space symmetric systems

The paper addresses the problem of analysis and static output feedback control synthesis for strict quadratic dissipativity of linear time-invariant systems with state-space symmetry. As a particular case of dissipative systems, we consider the mixed H_∞ and positive real performance criterion and we develop an explicit expression for calculating the H_∞ norm of these systems. Subsequently, an explicit parametrization of the static output feedback control gains that solve the mixed H_∞ and positive real performance problem is obtained. Numerical examples demonstrate the use and computational advantages of the proposed explicit solutions.     

On strict positive real systems design: guaranteed cost and robustness issues

This paper deals with unbounded nonlinear real uncertainty and proposes a solution to the strict positive real control problem by dynamic output feedback. Besides, a guaranteed cost problem, solved by LMI optimization combined with line search, is introduced in order to provide robust performance.     

Low frequency positive real control for delta operator systems

A strictly positive real control problem for delta operator systems in a low frequency range is presented by using the generalized Kalman–Yakubovic?–Popov lemma. The objective of the strictly positive real control problem is to design a controller such that the transfer function is strictly positive real and the resulting closed-loop system is stable. Sufficient conditions for the low frequency strictly positive real controller of the closed-loop delta operator systems are presented in terms of solutions to a set of linear matrix inequalities. A numerical example is given to illustrate the effectiveness and potential for the developed techniques.     

离散系统输出反馈强正实控制器综合

基于正实引理使用线性矩阵不等式(LMI)方法讨论了离散系统一般强正实控制问题的解,给出了任意阶输出反馈强正实控制器的存在条件.证明了给定离散系统可输出反馈强正实当且仅当三个LMI存在一个合适解,可低价输出反馈强正实当且仅当带秩约束条件的三个LMI存在一个合适解.     

线性多变量系统的鲁棒耗散控制

Robust quadratic dissipative control for a class of linear multi-variable systems with parameter uncertainties is considered, where the uncertainties are expressed in a linear fractional form. For the nominal system without uncertainties, the equivalence between quadratic dissipativeness and positive realness is established, and conditions are derived for linear systems to be quadratic dissipative. As for uncertain systems, it is shown that the robust quadratic dissipative control problem for the uncertain system can be reduced to the corresponding problem for a related system without uncertainties. The control problem concerned can be solved using LMI approach. The results of the paper unify existing results on H1 control and positive real control and provide a more flexible and less conservative control design method.     

线性对象的正实控制问题

在时域中考虑线性对象的正实控制(PRC)问题.对于一般的广义对象,在状态空间中提出了一个基于线性矩阵不等式(LMI)的统一处理PRC问题的方法,指出’PRC问题可解的充分必要条件是与系统的实现有关的三个LMI可解,并可利用LMI的解构造出所有的正则PR控制器.此外还提出了降价PR控制器的存在条件并讨论了可行的综合方法.     

输出反馈严格正实控制器设计

基于强严格正实引理，采用线性矩阵不等式方法讨论一般严格正实控制问题的解，给出了任意阶输出反馈严格正实控制器的存在条件和所有控制器的参数化形式。     

New bounded real lemma for discrete-time singular systems

In this paper, the problem of bounded real lemma for discrete-time singular system with strict matrix inequalities is investigated. It is proved that the bounded real lemma for discrete singular system can be described by a strict matrix inequality. The results lead to more tractable and reliable computation when applying them to design control systems.     

Dissipative control systems synthesis with full state feedback

In this paper we present a general framework for synthesizing state feedback controllers to achieve any desired closed loop dissipative behavior. Special cases include positive real andH _∞ controller synthesis. We show that the solution to this dissipative controller synthesis problem is equivalent to the existence of a solution to a partial differential inequality (nonlinear systems case) or an algebraic Riccati inequality (linear systems case). Stability results can be obtained under appropriate detectability assumptions, and a generalization of the strict bounded real lemma is given. We also present an application of the results to a robust stabilization problem. This work was supported by the Cooperative Research Centre for Robert and Adaptive Systems (CRASys), Australia.     

Robust dissipative control for linear systems with dissipative uncertainty and nonlinear perturbation

This paper focuses on the problem of dissipative control for linear systems which are subjected to dissipative uncertainty and matched nonlinear perturbation. Specifically, quadratic dissipative uncertainty is considered, which contains norm-bounded uncertainty, positive real uncertainty and uncertainty satisfying integral quadratic constraints (IQCs) as special cases. We develop a linear matrix inequality (LMI) approach for designing a robust nonlinear state feedback controller such that the closed-loop system is quadratic dissipative for all admissible uncertainties. Furthermore, under some condition on the dissipative uncertainty, we show that the controller also guarantees the asymptotic stability of the closed-loop system. As special cases, robust H_∞ control and robust passive control problems for systems with nonlinear perturbation and norm-bounded uncertainty (respectively, generalized positive real uncertainty) are solved using the LMI approach.     

二次型耗散线性离散系统的鲁棒性分析与控制

考虑一类不确定离散多变量系统的鲁棒二次型耗散性分析和控制,其中各不确定参数矩阵具有线性分式形式.首先对确定系统建立二次型耗散性与正实性之间的等价关系,由此导出线性系统二次型耗散的充分必要条件;然后证明不确定系统的鲁棒耗散性分析和控制可转化为确定系统的耗散性分析和设计,给出了这类不确定系统鲁棒耗散的充分必要条件以及鲁棒耗散控制问题的线性矩阵不等式解法.所得结果可将H∞控制与正实控制统一起来,提供一种较为灵活、保守性较小的系统设计方法.仿真例子说明了所提方法的有效性.