Stabilization of discrete nonlinear systems based on control Lyapunov functions

The stabilization of discrete nonlinear systems is studied. Based on control Lyapunov functions, a sufficient and necessary condition for a quadratic function to be a control Lyapunov function is given. From this condition, a continuous state feedback law is constructed explicitly. It can globally asymptotically stabilize the equilibrium of the closed-loop system. A simulation example shows the effectiveness of the proposed method.     

Robust stabilization for multi-input polytopic nonlinear systems

This paper deals with the problem of the stabilization for multi-input polytopic nonlinear systems. Based on the robust control Lyapunov function, a sufficient condition for the existence of time-invariant, continuous, asymptotically stabilizing state feedback controller is derived. It is shown that the obtained sufficient condition is also necessary if there exists a state feedback controller such that the closed-loop system has a robust Lyapunov function for all possible uncertainties. Moreover, a universal formula for constructing stabilizing controller is proposed and the existence of the corresponding Lyapunov function is proven. Particularly, a Lyapunov function is constructed for the polytopic nonlinear system in canonical form. Finally, the feasibility of the proposed control law is verified by a numerical example.     

基于分段模糊Lyapunov方法的离散模糊控制系统设计

针对应用公共Lyapunov函数方法和模糊Lyapunov函数方法判定离散T-S模糊控制系统稳定性存在的保守性和难度，在定义离散型分段模糊Lyapunov函数的基础上，应用并行分布补偿方法（PDC）设计出使模糊系统全局渐近稳定的拉制器，并提出和证明了一个新的判定用环离散T-S模糊系统稳定的充分条件，该条件降低了上述方法的保守性和难度。通过一个仿真例子验证了方法的有效性。     

Robust Stabilization for Uncertain Control Systems Using Piecewise Quadratic Lyapunov Functions

The sufficient condition based on piecewise quadratic simultaneous Lyapunov functions for robust stabilization of uncertain control systems via a constant linear state feedback control law is obtained. The objective is to use a robust stability criterion that is less conservative than the usual quadratic stability criterion. Numerical example is given, showing the advanteges of the proposed method.     

On Stabilization of It Stochastic Time-Varying Systems

The stabilization with receding horizon control(RHC) of It stochastic time-varying systems is studied in this paper. Based on monotonically non-increasing of optimal cost and stochastic Lyapunov stability theory, a necessary and sufficient stabilization condition on the terminal weighting matrix is proposed, which guarantees the mean-square stability of the closed-loop system. The explicit receding horizon controller is obtained by employing stochastic maximum principle. Simulations demonstrate the effectiveness of the proposed method.     

Convergence and stability of the Newton-Like algorithm with estimation error in optimization flow control

The Newton-Like algorithm with price estimation error in optimization flow control in network is analyzed.The estimation error is treated as inexactness of the gradient and the inexact descent direction is analyzed.Based on the optimization theory,a sufficient condition for convergence of this algorithm with bounded price estimation error is obtained.Furthermore,even when this sufficient condition doesn't hold,this algorithm can also converge,provided a modified step size,and an attraction region is obtained.Based on Lasalle's invariance principle applied to a suitable Lyapunov function,the dynamic system described by this algorithm is proved to be global stability if the error is zero.And the Newton-Like algorithm with bounded price estimation error is also globally stable if the error satisfies the sufficient condition for convergence.All trajectories ultimately converge to the equilibrium point.     

非线性中立型控制系统的鲁棒稳定与鲁棒镇定

研究了一类不确定性的非线性中立型动态系统,系统具有多重时不变状态时滞。其不确定性满足范数有界条件。采用LyapunovV泛函的方法。建立了一类Lyapunov泛函。通过对控制系统(B,D,C)的分析,得出只要矩阵对(B,D)是完全可控的,或者是可稳定的,则在相应的条件下便得出相应的非线性中立型动态控制系统及滞后型动态系统可镇定的充分条件。建立了非线性中立型微分系统的时滞无关的渐近稳定性判别条件,以及非线性中立型动态控制系统的时滞无关鲁棒镇定的判据。同时,给出了相应的非线性滞后微分系统的时滞无关鲁棒稳定性的判据,以及非线性滞后动态控制系统的时滞无关鲁棒镇定性的代数判据。     

不确定时滞系统的指数稳定保代价可靠控制

针对一类含有时变时滞的不确定参数系统,研究了在执行器发生故障情况下系统指数稳定保代价可靠控制器设计问题。系统的性能函数是含有指数项和故障输入项的积分二次型函数。经过适当的状态变换,将原系统的指数稳定保代价可靠控制问题转化为另一个等价系统的保代价可靠控制问题。根据Lyapunov稳定性理论,得到了系统存在指数稳定保代价可靠控制器应满足的一个矩阵不等式,进一步将这个矩阵不等式转化为线性矩阵不等式(LMI),并给出了系统的保代价表达式。利用论文方法设计的控制器能够使得时滞系统对于任意允许的不确定量以及执行器故障都保持鲁棒可靠指数稳定,并且使系统具有保代价的性能指标。仿真结果表明了该控制器设计方法的有效性。     

反馈可线性化系统全局跟踪控制器的设计

研究反馈可线性化的非线性系统全局跟踪参考信号的问题,将全局跟踪问题转化为误差系统的全局镇定问题。由Riccati方程获得了反馈可线性化系统的控制Lyapunov函数,证明了所得到的控制Lyapunov函数正是误差系统的控制Lyapunov函数。应用Sontag的通用公式,设计了全局跟踪控制器,并应用于单关节机器手跟踪参考信号的控制,仿真说明了所提出方法的有效性。     

一类切换系统的鲁棒状态反馈控制

考虑了一类非线性不确定切换系统的鲁棒状态反馈稳定问题，不确定项包含了系统矩阵的摄动以及满足匹配条件和不满足匹配条件三部分．对于给定的不确定切换系统，研究了其二次稳定和渐近稳定问题．基于公共李雅普诺夫函数方法，以矩阵不等式的形式给出了非线性切换系统鲁棒状态反馈稳定的若干充分条件．仿真结果验证了文中结论的正确有效性。     

Finite time stability and stabilization of hybrid dynamic systems

Finite time stability and stabilization are studied for hybrid dynamic systems. By combining multiple Lyapunov function and finite time Lyapunov function, a sufficient condition of finite time stability is given for the system. Compared with the previous works, our results have less conservativeness. Furthermore, based on the state partition of continuous and resetting parts of system, a hybrid feedback controller is constructed, which stabilizes the closed-loop systems in finite time. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed method.     

T-S模糊系统的一种新型PDC鲁棒模糊控制器设计

针对一类模有界的参数不确定Takagi-Sugeno(T-S)模糊系统,在分析模糊系统前提规则结构的基础上,设计了一种新的并行分配补偿(PDC)控制器,研究了其鲁棒控制问题。基于分段Lyapunov稳定性理论,导出了线性矩阵不等式(LMI)形式的鲁棒控制器设计方法。该方法充分利用了模糊系统隶属度函数的结构信息,降低了采用线性矩阵不等式方法求解的难度。仿真实验证明,通过该方法设计的模糊控制系统,具有良好的鲁棒性能,控制效果良好。     

T-S模糊系统的鲁棒局部稳定

研究一类不确定T-S模糊系统的鲁棒局部稳定及鲁棒局部镇定问题。首先给出T-S模糊系统局部稳定的定义,并利用一种非二次Lyapunov函数得到T-S模糊系统鲁棒局部稳定的充分条件,然后给出一种新的非PDC控制器,进而利用非二次Lyapunov函数得到基于这种非PDC控制器的局部鲁棒镇定控制器设计方法。该方法基于线性矩阵不等式(LMI),结构简单,且具有较低的保守性。仿真算例证明了所提方法的可行性。     

Improved forwarding control design method and its application

1.INTRODUCTIONThis paper addresses the problemof global stabilization ofthe feed-forword nonlinear system.The stabilization ofsystems withthisstructure has been widelyinvestigatedinthe recent years[1,2].The key way of dealing withsuchaproblemistofindthe solutionfor theintegral.However,in many cases,tofindsuch a solutionis not easy,or theintegral may not be solvable.According to this problem,we propose a design methodandshowthatindeedtheideaproposedin Ref.[1]can befurther developed.Moreov…     

基于T-S模糊模型的非线性时滞系统的变结构控制

基于T-S模糊模型和变结构控制策略,研究了一类带有参数不确定项的非线性时滞系统的变结构控制问题。首先,利用变结构控制理论选择滑模面,根据可达条件提出了一种变结构控制方法,该方法确保系统的运动轨迹在有限时间内到达滑模面并一直保持在滑模面上。当不确定项不满足匹配条件时,根据Lyapunov稳定性理论和线性矩阵不等式(LMI)的方法得到了系统状态全局稳定的充分条件。最后给出了一个仿真加以说明该设计方法的有效性。     

高阶随机非线性系统状态反馈镇定

针对一类高阶下三角随机非线性系统,提出一种新的镇定方案,采用增加一个幂积分的工具构建了一个全局稳定的光滑状态反馈控制律。通过反馈占有设计方法和Young不等式处理随机系统的非线性项,取消了对随机非线性系统反馈线性化和控制输入呈线性的要求,基于Lyapunov方法,证明了闭环系统依概率全局渐近稳定。最后,仿真实例说明了算法的可行性。     

时延通信网络的新型指数稳定跟踪控制器设计

针对一个具有单瓶颈和多用户的高速通信网络,提出了一个新的指数稳定跟踪控制器的设计方法。将闭环数据率控制系统描述为一个连续时间时变时滞系统,基于线性矩阵不等式(LMI)技术和Lyapunov方法给出了闭环系统时滞依赖的指数稳定充分条件。导出了状态反馈控制器的设计方法,使得实际网络带宽分配率和实际队列长度在该控制器的作用下分别以指数速度跟踪上给定的参考值,从而有效降低了数据包丢失率,提高了网络利用率。通过在闭环系统指数稳定条件的导出过程中引入自由变量的方法使得得到的时滞依赖条件具有更小的保守性,并且闭环系统具有更快的指数稳定跟踪速度。仿真算例验证了本文方法的有效性和优越性.     

Asymptotic controllability of a class of discrete-time systems with disturbances

This article deals with the uniformly globally asymptotic controllability of discrete nonlinear systems with disturbances. It is shown that the system is uniformly globally asymptotic controllability with respect to a closed set if and only if there exists a smooth control Lyapunov function. Further, it is obtained that the control Lyapunov function may be used to construct a feedback law to stabilize the closed-loop system. In addition, it is proved that for periodic discrete systems, the resulted control Lyapunov functions are also time periodic.     

基于分段模糊Lyapunov函数的模糊系统分析与设计

在分析模糊系统前提规则结构信息的基础上,将模糊Lyapunov函数和分段Lyapunov函数结合,构造出一类连续模糊系统的分段模糊Lyapunov函数。采用并行分配补偿(PDC)结构,利用分段模糊Lyapunov函数进行了稳定性分析与控制律设计,得到了线性矩阵不等式(LMI)形式的连续系统镇定方法。该方法减少了模糊Lyapunov函数与分段Lyapunov函数的局限性,继承两者的优点,所得稳定性判据更为宽松,控制系统具有良好的控制性能。仿真实例表明了该方法的有效性。     

一类线性时滞系统的未知输入观测器设计

以一类线性时滞系统为研究对象,研究了当观测误差与未知输入完全解耦时的未知输入观测器设计问题。基于时滞系统Lyapunov稳定性方法,给出了指数稳定未知输入观测器的存在条件。基于这一条件,提出了含有内部时滞与不含有内部时滞两种观测器的设计问题。通过求解线性矩阵不等式给出了所提观测器的设计方法。给出了两种情形下的观测器设计算法。数值例子说明了提出的设计方法的有效性。