离散饱和线性反馈系统的分析设计

研究了状态反馈控制饱和单输入离散系统和动态输出反馈单输出饱和离散系统的稳定性，给出了这两类系统是全局渐近稳定还是区域渐近稳定的充分性条件，且对区域渐近稳定的情况计算其不变吸引椭球，对控制饱和系统，运用Ricatti方程迭代法设计控制器以使所得椭球尽量大；最后用算例说明方法的有效性．     

运用静态反馈分析和设计饱和线性系统

给出了状态反馈控制饱和单输入系统和静态输出反馈单输出饱和线性系统是全局渐近稳定还是区域渐近稳定的充分性条件,且对区域渐近稳定的情况计算其不变吸引椭球,对控制饱和系统,运用Ricatti方程迭代法设计控制器以使所得椭球尽量大;对静态输出反馈多输出饱和线性系统,给出了其吸引域的描述,最后用算例说明方法的有效性。     

执行器饱和离散时间线性系统鲁棒稳定性

针对含执行器饱和离散时间线性参数依赖系统,分别采用独立的、仅参数依赖、同时参数和饱和依赖的二次李亚普诺夫函数方法去估计其不变吸引域,分别导出系统有着不变吸引椭球的以线性矩阵不等式(LMIs)表述的充分性条件。为得到保守性小的估计,分别提出了以上述LMIs作约束的相应优化算法。最后,算例显示同时参数和饱和依赖李亚普诺夫函数处理法所得结果的保守性较之其它两法要小。     

Parallel simultaneous stabilization of a set of Port-Controlled Hamiltonian systems subject to actuator saturation

This paper investigates parallel simultaneous stabilization (PSS) of a set of multi-input nonlinear Port-Controlled Hamiltonian (PCH) systems subject to actuator saturation (AS), and proposes a number of results on the design of PSS controllers for the PCH systems with AS. Firstly, the case of two PCH systems with AS is studied. Exploring the special property of the saturation nonlinearity and the structural properties of dissipative Hamiltonian system, the two systems are combined to generate an augmented PCH system, with which some results on the control design are then obtained. When there are external disturbances in the two systems, a robust PSS controller is designed for the systems. Secondly, the case of more than two PCH systems with AS is investigated, and several new results are proposed for the PSS problem. Finally, two illustrative examples are presented to show that the stabilization controllers obtained in this paper work very well.     

Finite-time control of formation system for multiple flight vehicles subject to actuator saturation

This paper investigates the problem of formation tracking control for multiple flight vehicle(MFV) system considering actuator saturation constraints. First, the formation tracking control model is established. Then, the problem of formation control of the MFV system is converted to the convergence of a dynamical system, which is obtained by using the differential geometry theory.A class of saturation functions is introduced, and on this basis a second-order finite-time formation control protoco...     

具有饱和执行器跳变系统的鲁棒模型预测控制

针对一类具有饱和执行器的不确定离散Markov跳变系统,提出鲁棒模型预测控制器设计方法。为便于工程应用,考虑被控跳变系统各模态下的动态系统参数以及各模态间的跳变转移模态均存在不确定性的情形,这些不确定性均以凸多面体的形式给出。预测控制器的求解通过在每一个采样时刻优化无穷时域的最坏二次性能指标实现,该预测控制序列在每个采样时刻表现为具有饱和特性的状态反馈控制律,从而使得所形成的闭环系统鲁棒均方稳定。为方便求解,将控制器的求解转化为以线性矩阵不等式形式给出的正半定规划(SDP)问题。数值示例验证了所提方法的有效性。     

传感器饱和约束下连续随机系统的鲁棒故障检测

考虑传感器输出饱和约束条件,研究了一类连续随机系统的鲁棒故障检测问题.基于线性矩阵不等式(LMI)技术,提出了保证故障检测系统一致有界均方稳定、且满足给定H_∞性能指标的充分条件, 同时给出鲁棒故障检测滤波器的系统化设计方法.数值仿真结果表明了所提方法的有效性.     

Simultaneous quadratic performance stabilization for linear time-delay systems

1.INTRODUCTION The simultaneous stabilization problem is concerned with the design of a single feedback controller P stabilizing every member of a collection of systems that is M 1 , M 2, … , Mr. In this case, the controller P is called the simultaneous stabilization controller. The motivation behind the simultaneous stabilization problem stems from the stability requirement of a system operating in different modes. For example, an industrial plant may be subject to different modes owi…     

Control and optimization of sampled-data systems with quantization and actuator saturation

This paper is concerned with control and optimization for a sampled-data system with quantization and actuator saturation. Based quantization and actuator saturation a controller is introduced. The corresponding closed loop system is transformed into a system with input saturation and bounded external disturbance. A new Lyapunov functional is constructed to derive a sample-interval dependent condition on the existence of a state feedback controller such that the closed-loop system is exponentially convergent to an ultimate ellipsoid for the initial condition starting from some initial ellipsoid. Based on the condition, the desired controller is designed. Furthermore, optimization problems about the sample-interval, the ultimate ellipsoid and the initial ellipsoid are formulated. An example is given to illustrate the effectiveness of the proposed method.     

Admissibility analysis and control synthesis for switched linear singular systems

The problem of admissibility analysis and control synthesis of discrete-time switched linear singular (SLS) systems for arbitrary switching laws is solved. By using the switched Lyapunov function approach, some new sufficient conditions under which the SLS system is admissible for arbitrary switching laws are derived in terms of linear matrix inequalities (LMIs). Based on the admissibility results, control synthesis is then to design switched state feedback and static output feedback controllers, guaranteeing that the resulting closed-loop system is admissible. The presented results can be viewed as the extensions of previous works on switched Lyapunov function approach from the regular switched systems to singular switched cases. Examples are provided to demonstrate the reduced conservatism and effectiveness of the proposed conditions.     

不确定离散时滞控制饱和系统L2增益分析设计

针对离散时间不确定含时滞和控制饱和系统的镇定和干扰抑制问题,提出了状态反馈和抗饱和动态输出反馈方法。该方法利用Lyapunov函数可获得时滞相关的线性矩阵不等式。线性矩阵不等式条件可保证不确定闭环系统的无干扰时鲁棒内稳定性和在某椭球内预先给定的有干扰时L2性能水平。通过把状态反馈增益视为一自由参数,利用所得到的优化问题给出了控制器设计的具体步骤,通过仿真算例证明该方法的有效性。     

Composite nonlinear feedback control for output regulation problem of linear discrete-time systems with input saturation

Transient performance for output regulation problems of linear discrete-time systems with input saturation is addressed by using the composite nonlinear feedback（CNF） control technique. The regulator is designed to be an additive combination of a linear regulator part and a nonlinear feedback part. The linear regulator part solves the regulation problem independently which produces a quick output response but large oscillations. The nonlinear feedback part with well-tuned parameters is introduced to improve the transient performance by smoothing the oscillatory convergence. It is shown that the introduction of the nonlinear feedback part does not change the solvability conditions of the linear discrete-time output regulation problem. The effectiveness of transient improvement is illustrated by a numeric example.     

Global stabilization of linear systems with bounded controls using state-dependent saturation functions

By using the so-called SP-stable polynomials, this paper reconsiders the problem of global stabilization of linear systems with input saturation. Firstly, a new nonlinear feedback law consisting of parallel connections of saturation functions by means of the so-called state-dependent saturation function is proposed for global stabilization of chains of integrators system. The state-dependent saturation function allows increasing the control energy when some of the states are badly scaled and can improve significantly the transient performances of the closed-loop system. Secondly, this type of global stabilization nonlinear feedback laws is extended to a class of linear systems that can be globally stabilized by bounded controls. Numerical examples show the effectiveness of the proposed approach.     

Robust reliable H∞ control for discrete-time Markov jump linear systems with actuator failures

The robust reliable H∞ control problem for discrete-time Markovian jump systems with actuator failures is studied. A more practical model of actuator failures than outage is considered. Based on the state feedback method, the resulting closed-loop systems are reliable in that they remain robust stochastically stable and satisfy a certain level of H∞ disturbance attenuation not only when all actuators are operational, but also in case of some actuator failures, The solvability condition of controllers can be equivalent to a feasibility problem of coupled linear matrix inequalities （LMIs）. A numerical example is also given to illustrate the design procedures and their effectiveness.     

Fault detection for networked systems subject to access constraints and packet dropouts

This paper addresses the problem of fault detection(FD) for networked systems with access constraints and packet dropouts.Two independent Markov chains are used to describe the sequences of channels which are available for communication at an instant and the packet dropout process,respectively.Performance indexes H∞ and H_ are introduced to describe the robustness of residual against external disturbances and sensitivity of residual to faults,respectively.By using a mode-dependent fault detection filter(FDF) as residual generator,the addressed FD problem is converted into an auxiliary filter design problem with the above index constraints.A sufficient condition for the existence of the FDF is derived in terms of certain linear matrix inequalities(LMIs).When these LMIs are feasible,the explicit expression of the desired FDF can also be characterized.A numerical example is exploited to show the usefulness of the proposed results.     

嵌入式实时调度系统抖动稳定性分析

分析了嵌入式实时调度系统中控制任务的采样周期和延时不规则抖动属性及稳定性能。并且,针对抖动范围有界但抖动属性不能精确已知的离散状态系统,提出一个保守的系统稳定性充分判据。该判据将抖动引起的时变不确定性描述为系统的离散时间闭环区间状态矩阵,利用李雅普诺夫方程和矩阵的无穷范数,导出区间系统鲁棒稳定的充分条件。该方法计算量小且能减小区间代数计算结果易于扩张的问题。仿真算例表明该判据简单有效且能降低保守性。     

执行器有故障时关联大系统的可靠H∞控制

针对一类具有常时滞、执行器故障和参数不确定性的关联大系统可靠H∞控制问题,提出了可靠H∞控制器的设计方法,其中参数不确定性满足匹配条件,而执行器故障采取比通常的离散故障模型更实际的连续增益故障模型。本文的目的是设计无记忆分散控制器镇定被控系统。利用线性矩阵不等式获得该控制器,使得系统在此控制器下无论是否发生故障都保持渐近稳定,并且具有一定的H∞性能指标。通过仿真的例子,验证该分散状态反馈控制器的可行性。     

一类不确定执行器非线性系统的自适应控制

针对一类带不确定执行器非线性的控制系统,提出了一种自适应神经网络控制方法。建立了包括死区、齿隙和“类齿隙”磁滞特征的非线性执行器模型。通过结合所建立的模型和Nussbaum增益技术,解决了当执行器非线性不确定时的控制问题。所设计的方案不需知道非线性特征参数边界,并且当非线性特征为死区时,其坡度可以为时变的。引入了自适应补偿项消除建模误差和干扰的影响。仿真结果验证了该方法的有效性。     

线性时滞系统的鲁棒故障诊断

研究了一类含有未知输入干扰和模型不确定性的时滞系统故障诊断问题。通过变换,原系统被分成两个子系统,一个子系统不受故障的影响,可以设计鲁棒观测器;另一个子系统受到故障的影响,但是它的状态可以通过测量得到。设计的观测器利用解析冗余方法能够对执行器故障和传感器故障进行诊断。仿真结果表明,算法具有良好的诊断性能。     

离散Markov跳变线性系统最优控制

针对离散Markov跳变系统,研究其最优控制问题。首先确立一个二次型代价函数,然后运用随机贝尔曼动态规划法,结合Markov跳变系统特性求解贝尔曼方程,获得了完全状态信息情形下Markov跳变系统的最优控制器和黎卡提差分方程;进而将其推广到不完全状态信息情形,利用观测向量获得状态的后验概率密度函数,推导了最优控制器的解析结构和相应的求解算法;最后通过数值仿真验证了所得控制器的有效性。