多故障并发非线性系统一体化跟踪主动容错控制器设计

针对一类执行器及传感器同时发生故障的非线性系统,综合鲁棒滑模重构观测器及自适应滑模容错控制器设计技术,提出一体化跟踪主动容错控制方案.首先,将系统增维变换为广义系统,运用广义约束逆引入辅助矩阵,采用线性矩阵不等式设计观测器系数矩阵,综合自适应律给出广义鲁棒滑模观测器设计程式;在此基础之上,通过设计鲁棒滑模微分器估计输出向量微分,结合广义鲁棒滑模观测器状态估计结论,实现执行器及传感器故障同时重构.其次,基于故障重构及状态估计结论,提出自适应滑模的跟踪主动容错控制律设计程式.最后,通过开展飞行模拟转台伺服系统数值仿真,检验一体化跟踪主动容错控制器设计方法的有效性.     

基于LMI的鲁棒控制器设计

研究了时域线性系统的鲁棒控制分析与综合,提出了将鲁棒控制设计问题转化为线性矩阵不等式（ＬＭＩ）形式的方法,给出了鲁棒控制器的标准ＬＭＩ结构,并通过求解ＬＭＩ得到鲁棒控制棒。文中以双转子涡喷发动机控制器设计为例风言风语地基于ＬＭＩ的鲁棒控制器,表明所给方法是可行的。     

基于LMI的H∞鲁棒PID控制器设计

针对一类线性系统,研究了基于H∞的鲁棒PID控制器的设计方法,使得闭环系统的所有极点均位于一个给定的LMI区域中.采用线性矩阵不等式的处理方法,证明了该问题等价于一组线性矩阵不等式的可解性问题.利用该线性矩阵不等式的可行解给出了PID控制器的构造方法,并通过现有的软件Matlab中的工具箱LMI来进行求解.该方法很好地解决了PID控制下的极点指标和H∞鲁棒控制的相容性问题.实际的工程算例验证了该方法的有效性和可行性.     

观测器型H∞控制器设计的LMI方法

观测器型控制器由于其结构简单和物理意义明确而受到广泛重视.在假定控制器为一般的动态补偿器情况下,利用LMI技术解H∞控制器使得未知参数较多且求取过程复杂.现利用LMI技术研究观测器型H∞控制器,则控制器参数可通过三个LMI即可获得,这个LMI组的适定性问题用现有的工具软件即可确定.     

基于NCS时延模型的鲁棒容错控制器

研究了一类具有未知扰动和参数不确定性的网络化控制系统的鲁棒容错控制问题.针对NCS的时延和不同步对系统产生的影响,基于将时延的不确定性转换为系统状态方程系数矩阵不确定性的NCS模型,同时考虑系统参数不确定性和未知扰动对系统的影响,应用Lyapunov稳定性理论和LMI方法,采用状态反馈控制策略,推证出了保证闭环网络化控制系统在执行器或传感器发生失效故障时仍渐近稳定的充分条件,并通过求解线性矩阵不等式组方便地得到了容错控制器的设计方法,最后用仿真算例验证了此方法的可行性和有效性.     

基于观测器的鲁棒H2控制器设计

研究了一类含有参数不确定系统的观测器型鲁棒H2控制器的设计问题.基于状态反馈和观测器设计的可分离性原理,给出了控制器存在的充分条件和系统H2性能指标的一个上界.利用线性矩阵不等式凸优化方法还得到了使该界达到最小的观测增益.     

基于观测器的鲁棒H_2控制器设计

研究了一类含有参数不确定系统的观测器型鲁棒 H2 控制器的设计问题 .基于状态反馈和观测器设计的可分离性原理 ,给出了控制器存在的充分条件和系统 H2 性能指标的一个上界 .利用线性矩阵不等式凸优化方法还得到了使该界达到最小的观测增益 .     

一体化执行器饱和线性矩阵不等式跟踪容错控制器设计

针对一类执行器幅值饱和的不确定非线性系统,提出了基于线性矩阵不等式的一体化主动容错控制器设计方法.考虑执行器传感器同时故障情形,采用系统增维方法,将原系统等效转化为仅含执行器故障虚拟系统,简化了容错控制器设计.其次采用凸组合法对执行器饱和非线性进行描述,确保控制输入始终在幅值范围以内.在此基础上,设计了集自适应估计律与控制器于一体的主动容错控制器,并将控制器增益解算方法,转化线性矩阵不等式约束下的优化问题.最后通过飞机数值算例验证了设计方法的有效性.     

不确定时滞系统基于观测器的鲁棒控制器设计

研究了不确定线性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，其中不确定性是时变的，通过构造增广系统，利用线性矩阵不等式方法，获得了该不确定系统存在状态观测器和基于观测器的鲁棒控制器的充分条件，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，所给示例说明了本文方法的设计步骤和有效性。     

基于LMI方法的不确定连续系统容错控制器设计

本文针对参数不确定系统,将执行器失效情况下闭环系统的二次稳定性容错器控制设计问题,转化为一个基于LMI约束的凸优化问题,通过判定此LMI问题的可行性从而可以得知该系统在执行器失效的情况下是否可以实现容错控制.若可以实现容错控制,则给出了控制器的一个可行解域.进而,还可以考虑系统的其他性能指标,实现多指标控制.     

Auxiliary signal design for robust active fault detection of linear discrete-time systems

In this paper, algorithms are proposed to design auxiliary signals for active fault detection based on a multi-model formulation of discrete-time systems. Two different scenarios are considered for this problem; the first one assumes there is no a priori information on initial conditions and no exogenous input signal, while the second allows for having a priori information and the possibility of having a known input in addition to the test signal. Approaches are proposed for solving these two types of problems which are capable of solving the problems efficiently. This is achieved by using a recursive approach based on the use of special Riccati equations. These algorithms can be used for systems of higher dimension and on longer time horizons than the existing methods.     

A robust fractional-order PID controller design based on active queue management for TCP network

In this paper, a robust fractional-order controller is designed to control the congestion in transmission control protocol (TCP) networks with time-varying parameters. Fractional controllers can increase the stability and robustness. Regardless of advantages of fractional controllers, they are still not common in congestion control in TCP networks. The network parameters are time-varying, so the robust stability is important in congestion controller design. Therefore, we focused on the robust controller design. The fractional PID controller is developed based on active queue management (AQM). D-partition technique is used. The most important property of designed controller is the robustness to the time-varying parameters of the TCP network. The vertex quasi-polynomials of the closed-loop characteristic equation are obtained, and the stability boundaries are calculated for each vertex quasi-polynomial. The intersection of all stability regions is insensitive to network parameter variations, and results in robust stability of TCP/AQM system. NS-2 simulations show that the proposed algorithm provides a stable queue length. Moreover, simulations show smaller oscillations of the queue length and less packet drop probability for FPID compared to PI and PID controllers. We can conclude from NS-2 simulations that the average packet loss probability variations are negligible when the network parameters change.     

LMI based stability analysis and robust controller design for discrete linear repetitive processes

Discrete linear repetitive processes are a distinct class of 2D linear systems with applications in areas ranging from long‐wall coal cutting through to iterative learning control schemes. The main feature which makes them distinct from other classes of 2D linear systems is that information propagation in one of the two independent directions only occurs over a finite duration. This, in turn, means that a distinct systems theory must be developed for them. In this paper, the major new development is that an LMI based re‐formulation of the stability conditions can used to enable the design of a family of control laws which have a well defined physical basis. It is also noted that this setting can be used to investigate robustness aspects. Copyright © 2003 John Wiley & Sons, Ltd.     

基于高阶控制器设计的线性自抗扰控制参数调整

将反馈控制器/扩张状态观测器闭环极点配置在同一位置是线性自抗扰控制器(linear active disturbance rejection control,LADRC)最常用的整定方法.该方法只需调整两个参数,在工程应用上极为方便.但是,由于极点配置在同一位置的限制,整定的LADRC可能达不到期望的性能.本文提出以现有控制器参数为基础的LADRC调参方法.该方法以现有控制器参数为基础,通过降阶及逼近,保证LADRC控制能接近现有控制系统的性能.仿真设计表明采用高阶控制器设计的LADRC可以取得与原有控制系统相当的控制性能.该方法不受带宽法调参的需使反馈控制器及扩张观测器极点配置在同一位置的限制,因此可以期望获得比带宽法更好的性能.同时,该方法为已经熟悉掌握其他控制器设计方法的工程控制人员提供了一种便捷的调整线性自抗扰控制参数的方案,具有较好的应用价值.     

Parameterized linear matrix inequality techniques in fuzzy controlsystem design

This paper proposes different parameterized linear matrix inequality (PLMI) characterizations for fuzzy control systems. These PLMI characterizations are, in turn, relaxed into pure LMI programs, which provides tractable and effective techniques for the design of suboptimal fuzzy control systems. The advantages of the proposed methods over earlier ones are then discussed and illustrated through numerical examples and simulations     

Sensor‐fault tolerance using robust MPC with set‐based state estimation and active fault isolation

In this paper, a sensor fault‐tolerant control scheme using robust model predictive control (MPC) and set‐theoretic fault detection and isolation (FDI) is proposed. The robust MPC controller is used to control the plant in the presence of process disturbances and measurement noises while implementing a mechanism to tolerate faults. In the proposed scheme, fault detection (FD) is passive based on interval observers, while fault isolation (FI) is active by means of MPC and set manipulations. The basic idea is that for a healthy or faulty mode, one can construct the corresponding output set. The size and location of the output set can be manipulated by adjusting the size and center of the set of plant inputs. Furthermore, the inputs can be adjusted on‐line by changing the input‐constraint set of the MPC controller. In this way, one can design an input set able to separate all output sets corresponding to all considered healthy and faulty modes from each other. Consequently, all the considered healthy and faulty modes can be isolated after detecting a mode changing while preserving feasibility of MPC controller. As a case study, an electric circuit is used to illustrate the effectiveness of the proposed scheme. Copyright © 2016 John Wiley & Sons, Ltd.     

LMI-based robust iterative learning controller design for discrete linear uncertain systems

This paper addresses the design problem of robust iterative learning controllers for a class of linear discrete-time systems with norm-bounded parameter uncertainties. An iterative learning algorithm with current cycle feedback is proposed to achieve both robust convergence and robust stability. The synthesis problem of the proposed iterative learmng control （ILC） system is reformulated as a γ-suboptimal H-infinity control problem via the linear fractional transformation （LFT）. A sufficient condition for the convergence of the ILC algorithm is presented in terms of linear matrix inequalities （LMIs）. Furthermore, the linear wansfer operators of the ILC algorithm with high convergence speed are obtained by using existing convex optimization techniques. The simulation results demonstrate the effectiveness of the proposed method.