一类非线性时滞系统的模糊预测控制

利用模糊T-S模型对一类输入受限的非线性时滞系统进行建模;在此基础上,提出了模糊预测控制,推导了预测性能指标上界,将稳定性约束,输入约束变换成容易求解的线性矩阵不等式形式。采用了并行分布补偿预测控制器,基于李雅普诺夫函数和线性矩阵不等式方法给出滚动时域优化的充分条件,证明了闭环系统的稳定性,仿真结果验证了所提方法的有效性。     

一类模糊跳变系统的采样控制器设计

针对含有马尔可夫跳变参数的模糊系统,采用多李亚普诺夫函数方法,设计采样控制器,保证模糊跳变系统指数均方稳定和随机稳定。为便于工程应用,考虑到控制系统多为数字控制系统,计算机的输入、输出控制信号是数字信号,而被控对象常为连续时间系统,文中采用离散的控制器控制连续的被控对象。系统模型中的每个跳变模态对应的子系统均是T-S模糊系统,对每个模糊子系统采用平行分布补偿的控制方法,保证子系统渐近稳定。控制器的求解等效为线性矩阵不等式的可解性问题,便于求解。数值仿真结果验证了方法的可行性和有效性。     

Robust generalized H2 control:time-delay case

Generalized H2 control problem is considered for a class of linear time-delay systems covering linear timeinvariant (LTI) case and time-varying but norm-bounded linear differential inclusion (NLDI) case. The issues focus on the synthesis of so-called generalized H2 controller, which guarantees internal/robust stability and a certain performance level of generalized H2 norm of resulting closed-loop system. By using Lyapunov functional technique, sufficient conditions for the existence of such a kind of controllers are obtained in terms of two linear matrix inequalities (LMIs).In the state space, for memoryless state feedback case, we treat the controller design in a unified framework for both LTI and NLDI. The presented results are illustrated by numerical examples.     

Delay-dependent passive control of linear systems with nonlinear perturbation

The problem of delay-dependent passive control of a class of linear systems with nonlinear perturbation and time-varying delay in states is studied. The main idea aims at designing a state-feedback controller such that for a time-varying delay in states, the linear system with nonlinear perturbation remains robustly stable and passive. In the system, the delay is time-varying. And the derivation of delay has the maximum and minimum value. The time-varying nonlinear perturbation is allowed to be norm-bounded. Using the effective linear matrix inequality methodology, the sufficient condition is primarily obtained for the system to have robust stability and passivity. Subsequently the existent condition of a state feedback controller is given, and the explicit expression of the controller is obtained by means of the solution of linear matrix inequalities （LMIs）. In the end, a numerical example is given to demonstrate the validity and applicability of the proposed approach.     

Finite-time stability and stabilization of Markovian switching stochastic systems with impulsive effects

Many practical systems in physics,biology,engineering and information science exhibit impulsive dynamical behaviors due to abrupt changes at certain instants during the dynamical processes.The problems of finite-time stability analysis are investigated for a class of Markovian switching stochastic systems,in which exist impulses at the switching instants.Multiple Lyapunov techniques are used to derive sufficient conditions for finite-time stochastic stability of the overall system.Furthermore,a state feedback controller,which stabilizes the closed loop systems in the finite-time sense,is then addressed.Moreover,the controller appears not only in the shift part but also in the diffusion part of the underlying stochastic subsystem.The results are reduced to feasibility problems involving linear matrix inequalities (LMIs).A numerical example is presented to illustrate the proposed methodology.     

Robust fault detection for a class of nonlinear network control system with communication delay

To investigate a class of nonlinear network control system, a robust fault diagnosis method is presented based on the robust state observer. To access the objective that the designed robust filter is maximally tolerant to disturbances and sensitive to fault, the robustness and stability properties of the fault diagnosis scheme are established rigorously. Using the residual vector, a fault tolerant controller is established in order to guarantee the stability of the closed-loop system, and the controller law can be obtained by solving a set of linear matrix inequalities. Then, some relevant sufficient conditions for the existence of a solution are given by applying Lyapunov stability theory. Finally, a simulation example is performed to show the effectiveness of the proposed approach.     

离散模糊时滞系统的鲁棒LQ/H∞非脆弱控制

针对一类由T-S模糊模型描述的不确定离散非线性时滞系统,讨论其在控制器存在可加性摄动情形下的鲁棒LQ/H_∞非脆弱控制问题。通过构造适当的Lyapunov函数,给出以线性矩阵不等式形式表示的系统时滞依赖稳定的充分条件以及相应的鲁棒LQ/H_∞非脆弱控制器设计方法。数值仿真表明,所构造的控制器不仅能够保证闭环模糊时滞系统的鲁棒渐近稳定性,还能使系统达到一定的H_∞干扰抑制水平。     

不确定切换系统基于切换时间的动态输出反馈鲁棒H∞控制

借助平均驻留时间方法，讨论了一类不确定切换系统的动态输出反馈鲁棒H_∞控制问题。利用多Lyapunov函数法，以线性矩阵不等式的形式给出了使得该类闭环系统的动态输出反馈控制器存在的充分条件。同时,构建了基于切换驻留时间的切换律。在综合考虑最优化干扰抑制性能指标γ和求解的简便性后，给出了动态输出反馈控制器的设计算法。进一步的，将所得结果推广到任意切换律的情况。     

一类参数不确定性混沌系统的T-S模糊控制

针对一类参数不确定性混沌系统,首次提出利用区间矩阵理论描述其不确定性,进而用T-S模糊模型对其进行精确描述的新方法.在此T-S模糊模型的基础上,给出一种基于并行分布补偿(PDC)技术的状态反馈控制器设计方法,并用Lyapunov稳定性理论证明了闭环系统的鲁棒稳定性.该方法充分考虑了模糊子系统之间的相互作用.状态反馈控制器增益矩阵可以通过求解一组线性矩阵不等式(LMIs)获得.仿真结果验证了所提方法的有效性.     

不确定离散广义时滞系统的静态输出反馈控制

针对一类不确定离散时滞广义系统,给出了静态输出反馈控制器的设计方法.首先基于标称离散广义时滞系统的稳定条件,以受限线性矩阵不等式形式,得到闭环离散广义时滞系统正则、因果且渐近稳定的充分条件,同时利用受限矩阵不等式的可行解给出静态输出反馈控制器的设计方法;然后采用矩阵的正交补,把求受限线性矩阵不等式的可行解问题转化为求严格线性矩阵不等式的可行解;最后的数值实例说明了所给方法的有效性和正确性.     

Delay-dependent robust H∞ control of convex polyhedral uncertain fuzzy systems

The robust H∞ control problem for a class of uncertain Takagi-Sugeno fuzzy systems with time-varying state delays is studied. The uncertain parameters are supposed to reside in a polytope. Based on the delay-dependent Lyapunov functional method, a new delay-dependent robust H∞ fuzzy controller, which depends on the size of the delays and the derivative of the delays, is presented in term of linear matrix inequalities (LMIs). For all admissible uncertainties and delays, the controller guarantees not only the asymptotic stability of the system but also the prescribed H∞ attenuation level. In addition, the effectiveness of the proposed design method is demonstrated by a numerical example.     

Stability and guaranteed cost control for uncertain time-delay Lur'e systems

The problem of delay-dependent stability and guaranteed cost control （GCC） for a class of uncertain time-delay Lur＇e systems are studied. By using an improved integral inequality,a less conservative delay-dependent stability criterion is formulated as the feasibility problem of the linear matrix inequality （LMI）. The criterion is proved theoretically to be less conservative than some existing results for linear time-delay systems. Because of the fact that the matrices in the LMI-based stability criteria usually have different dimensions, different structures, and different variables, the conservatism analysis of the criteria is difficult. This study brings about a new insight into the comparison of conservatism among different stability criteria, which are expressed in certain LMI forms. The existence of the guaranteed cost controller is given in terms of matrix inequalities. The condition can be solved by using an iterative procedure and does not need any parameter tuning. A numerical example is given to illustrate the effectiveness of the proposed method.     

离散模糊时滞系统的鲁棒LQ/H_∞非脆弱控制

针对一类由T-S模糊模型描述的不确定离散非线性时滞系统,讨论其在控制器存在可加性摄动情形下的鲁棒LQ/H_∞非脆弱控制问题.通过构造适当的Lyapunov函数,给出以线性矩阵不等式形式表示的系统时滞依赖稳定的充分条件以及相应的鲁棒LQ/H_∞非脆弱控制器设计方法.数值仿真表明,所构造的控制器不仅能够保证闭环模糊时滞系统的鲁棒渐近稳定性,还能使系统达到一定的H_∞干扰抑制水平.     

Robust H∞ controller design for a class of nonlinear fuzzy time-delay systems

The problem of fuzzy modeling for state and input time-delays systems with a class of nonlinear uncertainties by fuzzy T-S model is addressed. By using the linear matrix inequality (LMI) method, the problem of fuzzy robust H∞ controller design for the system is studied. Assuming that the nonlinear uncertain functions in the model considered are gain-bounded, a sufficient condition for the robustly asymptotic stability of the closed-loop system is obtained via Lyapunov stability theory. By solving the LMI, a feedback control law which guarantees the robustly asymptotic stability of the closed-loop system is constructed and the effect of the disturbance input on the controlled output is ruduced to a prescribed level.     

Delay-dependent robust passivity control for uncertain time-delay systems

The robust passivity control problem is addressed for a class of uncertain delayed systems with time-varying delay. The parameter uncertainties are norm-bounded. First, the delay-dependent stability sufficient condition is obtained for the nominal system, and then, based-on the former, the delay-dependent robust passivity criteria is provided and the corresponding controller is designed in terms of linear matrix inequalities. Finally, a numerical example is given to demonstrate the validity of the proposed approach.     

变体飞行器连续平滑切换LPV控制

针对一类翼展可变飞行器的控制问题,提出了一种连续平滑切换线性变参数(linear parameter varying, LPV)控制器的设计方法。将变体飞行器建模成以翼展变形率为时变参数的LPV系统,通过对时变参数进行具有重叠特性的区间划分,设计平滑切换控制器。结合参数依赖的多李雅普诺夫函数和平均驻留时间方法,给出了保证切换LPV系统指数稳定的充分条件。由于考虑了时变参数的渐变特性,使得系统的切换律没有平均驻留时间的限制,降低了结论的保守性。仿真结果表明,运用所设计的控制器,当翼展连续变化时,变体飞行器状态稳定且切换过程平滑,控制性能良好。     

基于二维混合模型的鲁棒迭代学习控制设计

针对一类正则线性不确定系统,提出一种基于连续/离散二维混合模型的迭代学习控制设计方法。首先,通过独立地考虑迭代学习控制系统连续的控制行为与离散的学习行为,建立迭代学习控制系统的连续/离散二维混合模型,将迭代学习控制器设计问题转化为一类连续/离散二维系统的状态反馈控制问题。然后应用二维连续/离散系统方法,获得迭代学习控制系统稳定性条件。最后根据稳定性条件,利用线性矩阵不等式方法,求得迭代学习控制器参数,它通过Matlab工具箱可以方便的获得。与现有方法相比,所提出的迭代学习控制器利用了输出误差以及状态变化的信息来修正当前的控制,因而设计方法更加符合其本质特征,具有简单实用、直观明了的特点。数值仿真实例验证了所提方法的有效性。     

Fuzzy Static Output Feedback <Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> Control for Nonlinear Systems Subject to Parameter Uncertainties

This study is concerned with the stabilization issue of nonlinear systems subject to parameter uncertainties. An interval type-2 T-S fuzzy model is used to represent the nonlinear systems subject to parameter uncertainties. An interval type-2 fuzzy static output feedback controller is designed to synthesize the interval type-2 T-S fuzzy systems. The membership-function-dependent stability conditions are derived by utilizing the information of upper and lower membership functions. The proposed stability conditions are presented in the form of linear matrix inequalities (LMIs). LMI-based stability conditions for interval type-2 fuzzy static output feedback H_∞ control synthesis are also developed. Several simulation examples are given to show the superiority of the proposed approach.     

一类不确定混合线性时滞系统鲁棒控制问题研究

讨论了一类不确定混合线性时滞系统在其Markov跳跃参数所处模态非精确可测得情况下的鲁棒控制问题。给出了非匹配条件下系统不确定部分范数上界已知时,使系统呈均方意义下指数稳定的保代价控制充分条件。并根据混合系统模式下的LaSalle稳定性定理,对匹配条件下系统不确定部分的未知范数上界给出了一种参数自适应估计方法,设计了相应的鲁棒自适应控制律以实现混合线性时滞系统以概率1渐近稳定。鲁棒自适应控制律的设计仅依赖于跳跃参数的非精确测量值。