一类切换系统的动态输出反馈控制器设计

针对一类非线性扰动项不满足匹配条件的蚤确定切换系统鲁棒动态输出反馈镇定问题，采用单李雅普诺夫函数方法和变量替换方法，研究了状态矩阵和控制输入矩阵同时带有未知、时变但有界的不确定性，且有外界干扰的切换系统，给出了不确定切换系统鲁棒可稳的充分备件。仿真结果表明，所设计的动态输出反馈控制器及相应的切换策略保证了闭环系统渐近稳定。     

离散时延切换系统的鲁棒控制

针对一类子系统为离散时延系统并且参数具有不确定性的切换系统，研究了鲁棒控制以及H∞扰动抑制问题。通过为每个子系统施加状态反馈并基于多李雅普诺夫函数法，分别给出了保证闭环系统渐近稳定的鲁棒控制器以及具有H∞扰动抑制性能控制器的设计方法。控制器参数可通过一组矩阵不等式获得，使用将待解不等式转化为双线性矩阵不等式并采用巡回迭代算法对其求解。通过仿真例子说明了设计方法的有效性。     

线性时滞不确定连续系统的鲁棒容错控制研究

以线性不确定时滞系统为模型,应用李雅普诺夫稳定性理论和LMI工具箱,采用状态反馈控制器设计连续系统的容错控制器,研究了线性不确定时滞连续系统的状态反馈鲁棒稳定问题.给出了系统在执行器失效情况下渐近稳定的充分条件及相应的状态反馈鲁棒容错控制器的设计方法,仿真结果验证了该方法的可靠性和有效性.     

基于一致鲁棒精确微分器的直流电机输出反馈鲁棒控制

针对具有不可测状态和不确定非线性的直流电机位置伺服系统,提出一种基于一致鲁棒精确微分器(URED)的输出反馈鲁棒控制算法。所构造的一致鲁棒精确微分器不依赖于系统输入和参数,它只用于估计系统状态,并能保证状态估计的全局有界性以及有限时间的准确估计。鲁棒控制处理不确定非线性,通过李雅普诺夫方法从理论上证明了整个闭环系统的稳定性。由仿真结果可见,系统跟踪误差最大约为0.05 mm,相对跟踪误差约为0.25%,证明了所提算法的有效性。     

时滞不确定奇异系统的鲁棒H∞控制

针对带时滞的奇异系统，研究基于状态反馈的鲁棒H∞问题，系统的状态矩阵、状态滞后矩阵和输入矩阵均含有范数有界不确定项。采用Lyapunov泛函方法，给出了带时滞的不确定奇异系统鲁棒渐近稳定且具有H∞范数界γ充分条件；利用含等式约束的线性矩阵不等式（LMI）方法，给出了此类系统控制存在状态反馈的充分条件，该条件等价于严格线性矩阵不等式可解性问题，利用严格LMI的可行解，得到控制器矩阵的参数化表示。该鲁棒控制器的渐进稳定性条件宽松，克服了时滞奇异系统稳定性问题条件中的等式约束，控制器求解算法可行、高效，并通过一个数值实例说明了该方法的有效性。     

不确定滞后系统的鲁棒模型预测控制

对于输入受约束的离散不确定滞后系统，提出鲁棒模型预测控制方法，其中不确定性存在于系统的状态矩阵和输入矩阵当中，且满足范数有界条件。用LMI解决滞后系统的不确定性和约束，针对滞后系统给出了新的鲁棒性能指标上界和系统稳定的充分条件，通过求解LMI凸优化得到状态反馈控制律，对提出的方法进行了数字仿真研究，结果表明，基于LMI约束不确定滞后系统的鲁棒模型预测控制易于求解。适于实际应用。     

不确定分布式时滞系统的鲁棒H∞状态反馈控制

针对一类不确定分布式时滞系统的鲁棒H∞控制问题，采用线性矩阵不等式的方法通过选择适当的lyapunov函数，得到了自治系统的鲁棒渐进稳定的充分条件。推导出了闭环系统鲁棒渐近稳定的充分条件，并设计了无记忆性H∞状态反馈控制器，使得对于所有允许的不确定性，闭环系统鲁棒渐近稳定且具有给定的H∞性能指标。给出了控制器存在时滞相关的充分条件，且控制器参数能够通过求解线性矩阵不等式得到，对于一个高阶的数值仿真系统，通过对线性矩阵不等式的求解可以得到最优H∞性能指标，及相应不等式的解。仿真证明了该设计方案的有效性。     

不确定中立时滞系统的鲁棒H∞控制

研究了一类具有范数有界不确定性中立时滞系统的鲁棒H∞控制问题。利用线性矩阵不等式(LMI)方法，给出了在状态反馈作用下，不确定中立时滞系统鲁棒可镇定且具H∞范数界的充分条件。并且基于此条件给出了无记忆状态反馈鲁棒H∞控制器设计方法。鲁棒H∞控制器保证闭环系统鲁棒稳定且满足给定的H∞范数约束条件，并可通过求解相应的线性矩阵不等式(LMI)得到。最后，数值算例说明了方法的可行性。     

中立型时滞系统基于观测器的控制器设计

针对一类线性不确定中立型时滞系统的状态观测器和基于观测器的鲁棒控制器设计问题，通过构造增广系统，基于线性矩阵不等式的方法，椎导了此类不确定系统状态观测器和基于观测器的鲁棒控制器存在的时滞相关充分条件，同时给出了相应的状态观测器和基于观测器的鲁棒控制器的求解。数值实例证明了该设计方案的可行性。     

基于LMI的奇异不确定时滞系统鲁棒保成本控制

针对一类奇异不确定时滞系统的鲁棒保成本控制,假定其中的不确定性是范数有界,采用基于线性矩阵不等式（LMI）和构造适当的Lyapunov泛函相结合的方法,给出了系统的鲁棒保成本状态反馈控制器存在的条件。通过求解相应的线性矩阵不等式就可得到鲁棒保成本控制,所设计的保成本控制器对所有容许的不确定性不仅使得相应的闭环系统达到二次稳定,也能保证闭环成本函数不超过一个确定的界。通过数值算例及仿真验证了所给方法的有效性。     

Energy efficient nonfragile control protocol for nonlinear large-scale systems with input quantization

The problem of robust stabilization for a class of nonlinear large-scale systems with the energy constraints and time-varying actuator faults is addressed in this article. In the considered system, the stabilization criteria is achieved via a sensor-network-based distributed fault-tolerant controller. Moreover to limit the consumption of energy by the sensors, the measurement size reduction technique and communication rate reduction approach are implemented such that the resulting closed-loop system is stable within a predefined extended passive performance index level. In particular, the sensor signal quantization technique is used to reduce the frequency and size of the transmitted data packet in the communication sequence. Based on the switched system theory and Lyapunov approach, a new set of sufficient conditions is obtained in the form of linear matrix inequality constraints to ensure the exponential stabilization of the considered system. The developed fault-tolerant resilient control gains are designed by resorting to the cone complementarity linearization algorithm. Moreover, a nonisothermal continuous stirred-tank reactor with interconnection is considered as an example to demonstrate the effectiveness of the proposed design technique.     

A small‐gain approach for adaptive output‐feedback NN control of switched pure‐feedback nonlinear systems

This paper investigates the problem of adaptive output‐feedback neural network (NN) control for a class of switched pure‐feedback uncertain nonlinear systems. A switched observer is first constructed to estimate the unmeasurable states. Next, with the help of an NN to approximate the unknown nonlinear terms, a switched small‐gain technique‐based adaptive output‐feedback NN control scheme is developed by exploiting the backstepping recursive design scheme, input‐to‐state stability analysis, the common Lyapunov function method, and the average dwell time (ADT) method. In the recursive design, the difficulty of constructing an overall Lyapunov function for the switched closed‐loop system is dealt with by decomposing the switched closed‐loop system into two interconnected switched systems and constructing two Lyapunov functions for two interconnected switched systems, respectively. The proposed controllers for individual subsystems guarantee that all signals in the closed‐loop system are semiglobally, uniformly, and ultimately bounded under a class of switching signals with ADT, and finally, two examples illustrate the effectiveness of theoretical results, which include a switched RLC circuit system.     

Robust H ∞ filtering for a class of uncertain stochastic hybrid neutral systems with time‐varying delay

This paper is devoted to the problem of robust H _∞ filtering for a class of uncertain switched neutral systems subject to stochastic disturbance and time‐varying delay. Attention is focused on the design of a full‐order switched filter such that the filtering error system is robust mean‐square exponentially stable with a prescribed weighted H _∞ performance. On the basis of the average dwell time approach and the piecewise Lyapunov function technique, sufficient conditions for the solvability of this problem are obtained in terms of linear matrix inequalities. Then, by solving the corresponding linear matrix inequalities, the desired full‐order switched filter is derived for all admissible uncertainties, time‐varying delay, and stochastic disturbances. A numerical example is given to illustrate the effectiveness of the proposed method. Copyright © 2012 John Wiley & Sons, Ltd.     

Global adaptive finite‐time stabilization of a class of switched nonlinear systems with parametric uncertainty

This paper investigates the global adaptive finite‐time stabilization of a class of switched nonlinear systems, whose subsystems are all in p (p≤1) normal form with unknown control coefficients and parametric uncertainties. The restrictions on the power orders and the nonlinear perturbations are relaxed. By using the parameter separation technique, the uncertain parameters are separated from nonlinear functions. A systematic design procedure for a common state feedback controller and a switching adaptive law is presented by employing the backstepping methodology. It is proved that the closed‐loop system is finite‐time stable under arbitrary switching by utilizing the common Lyapunov function. Finally, with the application to finite‐time control of chemical reactor systems, the effectiveness of the proposed method is demonstrated. Copyright © 2015 John Wiley & Sons, Ltd.     

Switched adaptive stabilization of switched nonlinearly parameterized cascade systems and its application to a two inverted pendulums

This paper studies adaptive control of switched nonlinearly parameterized cascade systems. No solvability of the adaptive control problem for subsystems is required. By exploiting the multiple Lyapunov functions method and the parameter separation technique and the tool of adding a power integrator, we develop a new switched adaptive control approach for the explicit construction of adaptive controllers of subsystems and a proper switching law that solves the adaptive stabilization problem. A key feature of the proposed adaptive controllers is its switched property, namely, each subsystem has its individual update law. A two‐inverted pendulum as a practical example is also provided to demonstrate the effectiveness of the proposed design method. Copyright © 2014 John Wiley & Sons, Ltd.     

Robust fault detection and adaptive parameter identification for DC-DC converters via switched systems

In this paper, the problem of fault detection and identification for DC-DC converters is presented. First, switched systems model and fault model are analyzed based the switched characteristics of the DC-DC converters, taking the DC-DC buck converter as an example. According to the switched Lyapunov function technique, a fault detection observer and a bank of linear switched fault identification observers are designed for the switched systems. Next, the fault detection observer detects the fault based on the residual produced by the observer output and actual output. After the fault is detected, fault identification observers are activated. The location of fault is identified by comparing the residual evaluation functions. Meanwhile, the adaptive parameter identification is achieved by choosing an appropriate adaptive law. Finally, in order to show the feasibility of the fault detection and identification, the simulation results are given in this article.     

线性周期性切换系统的镇定及鲁棒镇定研究

针对线性周期性切换系统的镇定及鲁棒镇定问题,分别研究了确定的和结构不确定的线性周期性切换系统,利用状态反馈镇定或鲁棒镇定了该类系统。在镇定控制器的设计中使用了LMI方法,仿真实验验证了控制器的设计方法有效。     

Neural networks-based adaptive finite-time prescribed performance fault-tolerant control of switched nonlinear systems

In this article, the adaptive finite-time fault-tolerant control problem is considered for a class of switched nonlinear systems in nonstrict-feedback form with actuator fault. The problem of finite-time fault-tolerant control is solved by introducing a finite-time performance function. Meanwhile, the completely unknown nonlinear functions exist in the switched system are identified by the neural networks. Based on the common Lyapunov function method with adaptive backstepping technique, the finite-time fault-tolerant controller is designed. The proposed control strategy can guarantee that the tracking error converges to a prescribed zone at a finite-time and all system variables remain semiglobally practical finite-time stable. Numerical examples are offered to verify the feasibility of the theoretical result.