Delay-dependent robust exponential stabilization foruncertain systems with interval time-varying delays

New robust exponential stabilization criteria for interval time-varying delay systems with norm-bounded uncertainties are proposed. Based on the free-weighting matrices and new Lyapunov-Krasovskii functionals, such criteria are obtained by dealing with system model directly and designing memoryless state feedback controllers and expressed in terms of linear matrix inequalities （LMIs）. Moreover, the criteria are applicable to the case whether the derivative of the time-varying delay is bounded or not. The state decay rate is estimated by the corresponding LMIs. Numerical examples are given to illustrate the effectiveness of the proposed method.     

Guaranteed cost control for T-S fuzzy systems with time-varying delays

This paper deals with the problem of guaranteed cost control for nonlinear systems with time-varying delays which is represented by Takagi-Sugeno (T-S) fuzzy models with time-varying delays. The derivatives of timevarying delay are not necessary to be bounded. Based on the free weighting matrix method, sufficient conditions for the existence of fuzzy guaranteed cost controller via state feedback are given in terms of linear matrix inequalities (LMIs). A minimizing method is also proposed to search the suboptimal upper bound of the guaranteed cost function. The results are delay-dependent but contain delay-independent criteria as a special case. A numerical example is presented to demonstrate the effectiveness and less conservativeness of our work.     

Static output feedback stabilization for systems with time-varying delay based on a matrix transformation method

This paper is concerned with the problem of static output feedback stabilization for linear systems with time-varying delay. A novel controller design is proposed based on a matrix transformation method with a new equation condition, which can solve the controller gain more easily and avoid complicated calculations of the non-linear matrix inequality. Then, the corresponding criteria can be obtained by combining the matrix transformation method and the ideas of non-uniformly dividing delay interval, which can guarantee the asymptotic stability of the closed-loop systems and calculate the satisfactory controller gain. Finally, two numerical examples are provided to verify the effectiveness of the proposed design scheme.     

Further control synthesis for time-delay systems with actuator saturation

This paper is concerned with the control synthesis problem for systems with time-varying delay and actuator saturation. A new controller design method is proposed in which auxiliary feedback matrix method is adopted to handle the saturation term in the system. The improvement of the proposed method lies in the application of delay partitioning idea to further enlarge the estimated domain of attraction. All the results are given in terms of linear matrix inequalities. Finally, a numerical example is provided to demonstrate the effectiveness and superiority of our obtained results.     

Delay-dependent robust stabilization and H ∞ control for uncertain stochastic T-S fuzzy systems with discrete interval and distributed time-varying delays

In this paper, delay-dependent robust stabilization and H∞ control for uncertain stochastic Takagi-Sugeno (T-S) fuzzy systems with discrete interval and distributed time-varying delays are discussed. The purpose of the robust stochastic stabilization problem is to design a memoryless state feedback controller such that the closed-loop system is mean-square asymptotically stable for all admissible uncertainties. In the robust H∞ control problem, in addition to the mean-square asymptotic stability requirement, a prescribed H∞ performance is required to be achieved. Sufficient conditions for the solvability of these problems are proposed in terms of a set of linear matrix inequalities (LMIs) and solving these LMIs, a desired controller can be obtained. Finally, two numerical examples are given to illustrate the effectiveness and less conservativeness of our results over the existing ones.     

Controller Design for Networked Control System with Uncertain Parameters

This paper deals with the problem of controller design for NCSs （networked control systems） with uncertain parameters and network induced time-delays. In the case of long time delay constraint and data package loss, the closed-loop model of a class of NCSs is presented for controlled objects with uncertain parameters. Based on Lyapunov stability theory combined with LMIs （linear matrix inequalities） techniques, the design method of state feedback controller for NCSs with asymptotic stability is given in the form of LMIs. Numerical example and simulation suggest that the results are effective and are an improvement over previous ones.     

Observer design and output feedback stabilization for linear singular time-delay systems with unknown inputs

The design of a functional observer and reduced-order observer with internal delay for linear singular timedelay systems with unknown inputs is discussed. The sufficient conditions of the existence of observers, which are normal linear time-delay systems, and the corresponding design steps are presented via linear matrix inequality（LMI）. Moreover, the observer-based feedback stabilizing controller is obtained. Three examples are given to show the effectiveness of the proposed methods.     

Robust H-infinity control for discrete-time T-S fuzzy systems with input delay

Delay-dependent robust H-infinity control for discrete-time Takagi-Sugeno (T-S) fuzzy systems with interval time-varying input delay is considered.By constructing a new Lyapunov-Krasovskii functional and using convex combination method,a delay-dependent condition is established,under which the resulted closed-loop systems via a fuzzy state feedback are robust asymptotically stable with given H-infinity norm bound.Then,an iterative algorithm based on the modified SLPMM algorithm is proposed to solve the fuzz...     

Output Feedback Tracking Control for a Class of Switched Nonlinear Systems with Time-varying Delay

This paper studies the problem of tracking control for a class of switched nonlinear systems with time-varying delay. Based on the average dwell-time and piecewise Lyapunov functional methods, a new exponential stability criterion is obtained for the switched nonlinear systems. The designed output feedback H∞controller can be obtained by solving a set of linear matrix inequalities(LMIs).Moreover, the proposed method does not need that a common Lyapunov function exists for the switched systems, and the switching signal just depends on time. A simulation example is provided to demonstrate the effectiveness of the proposed design scheme.     

New results on robust H-infinity control for discrete-time systems with interval time-varying delays

This paper deals with delay-dependent robust H-infinity control for uncertain discrete-time systems with interval time-varying delay. By using a new Lyapunov functional and the convex combination method, a new delay-dependent stability criterion is established. Some redundant variable matrices are removed in the new conditions, which makes the obtained results more efficient. Then, an iterative algorithm based on the cone complementarity Linearization method is proposed to obtain the delay-dependent robust H-infinity controller. Numerical examples are given to show the effectiveness of the proposed method.     

线性时滞不确定系统的记忆与无记忆复合控制器设计

研究了一类时变滞后的不确定线性系统的控制综合问题。基于Lyapunov方法提出了一种含滞后补偿的鲁棒控制设计方法,给出了一个使得系统鲁棒稳定的包含无记忆和有记忆的状态反馈控制器。提出一种新的凸优化算法用于复合控制器设计,能保证在给定的不确定性范围内求得一个使系统镇定的次优解。     

改进的时延丢包网络控制系统的分析和控制

将网络控制系统建模为时变时滞系统模型,考虑有界、时变时延和丢包的网络控制系统的稳定性分析和控制器设计问题。首先构造一个新的分段Lyapunov-Krasovskii泛函,充分利用时延上下界信息,然后结合更紧的有限和不等式处理时滞区间,得到具有较小保守性的稳定性准则,基于一种改进的锥补线性化迭代算法给出状态反馈器设计方法,证明中没有引进模型变换和自由矩阵,减少了计算上的复杂性。通过实例表明上述方法的有效性。     

区间变时滞不确定线性系统带记忆H∞状态反馈控制

一类存在范数有界不确定性的线性时变时滞系统, 其时变时滞仅给出时滞变化的上下界, 而对时滞变化率未作任何约束. 对于这类区间时变时滞系统, 给出了一种新型的 Lyapunov-Krasovskii 泛函讨论其稳定性, 通过分割平均时滞的方法减小保守性, 得到以线性矩阵不等式(LMI)形式给出的稳定性判据. 最后分析并给出了一种带记忆的 H∞ 状态反馈控制器. 数值实例表明了本文方法的有效性.     

Robust control for a class of T-S fuzzy systems with interval time-varying delay

The problem of delay-dependent stability analysis and controller design for a class of T-S fuzzy systems with interval state time-varying delay is considered. Based on Lyapunov stability theory, defining a new Lyapunov-Krasovskii functional and introducing some free-weighting matrices, a new delay-dependent criterion is given to ensure the systems asymptotically stable. The merit of the proposed conditions lies in the less conservativeness than the existing ones, which is achieved by considering the mean of time-delay interval and the introduction of the free variables. By the concept of parallel distributed compensation (PDC), a delay-dependent condition for the existence of a fuzzy state feedback control law with memory is proposed. Another merit is the consideration of the memory of the controller. All conditions are shown in terms of linear matrix inequalities (LMIs), which can be solved efficiently by using the LMI optimization techniques. Two numerical examples are given to illustrate the feasibility and validity of the proposed approach.     

Exponential stabilisation for time-varying delay system with actuator faults: an average dwell time method

The issue of exponential stabilisation for a class of special time-varying delay switched systems resulting from actuator faults is considered in this article. The time-varying delay is assumed to belong to an interval and can be a slow or fast time-varying function. A hybrid state feedback strategy is redesigned to guarantee the system stable since the original controller is unavailable for some actuators failures. A class of switching laws incorporating the average dwell time method is proposed so that the special switched system with interval time-varying delay is exponentially stable. New delay-range-dependent stabilisation conditions using state feedback controllers are formulated in terms of linear matrix inequalities (LMIs) by choosing appropriate Lyapunov–Krasovskii functional without neglecting some useful knowledge on system states. Parameterised characterisations of the controllers are given in terms of the feasibility solutions to the LMIs. Two numeral examples are given to demonstrate the applicability and the effectiveness of the proposed method.     

具有时变不确定性的线性时滞系统的鲁棒H∞控制

研究具有一般形式的不确定线性时滞系统的鲁棒H∞状态反馈控制器设计问题.基 于二次H∞性能概念,首先证明了若存在鲁棒H∞动态状态反馈控制器,则必存在鲁棒H∞静 态状态反馈控制器,然后利用线性矩阵不等式给出了鲁棒H∞静态状态反馈控制器存在的充 分条件和构造方法,最后给出一个算例验证本文方法的有效性.     

Observer-based output feedback control of networked control systems with non-uniform sampling and time-varying delay

This paper investigates the problem of observer-based output feedback control for networked control systems with non-uniform sampling and time-varying transmission delay. The sampling intervals are assumed to vary within a given interval. The transmission delay belongs to a known interval. A discrete-time model is first established, which contains time-varying delay and norm-bounded uncertainties coming from non-uniform sampling intervals. It is then converted to an interconnection of two subsystems in which the forward channel is delay-free. The scaled small gain theorem is used to derive the stability condition for the closed-loop system. Moreover, the observer-based output feedback controller design method is proposed by utilising a modified cone complementary linearisation algorithm. Finally, numerical examples illustrate the validity and superiority of the proposed method.     

基于Razumikhin 方法的随机时变时滞非线性系统的状态反馈

采用Razumikhin 方法研究一类随机时变时滞非线性系统的状态反馈镇定问题. 利用随机系统的Razumikhin-Mao 理论和反推设计方法, 设计系统的状态反馈控制器, 所设计的控制器能保证闭环系统的平衡点为依概率全局渐近稳定的. 所提出的方法能够彻底地去掉关于随机时变时滞非线性系统传统结果中所要求的时滞导数的限制. 仿真示例验证了所提出状态反馈控制器的有效性.

     

一类具有连续分布时滞的分布参数系统的反馈控制

针对一类同时具有变时滞和连续分布时滞的分布参数系统的状态反馈控制问题进行了研究,通过选择适当的Lyapunov-Krasovskii函数,采用线性矩阵不等式(LMI)方法,得到了变时滞闭环系统渐近稳定的一个充分条件.设计了无记忆的状态反馈控制器,使得在一个正定矩阵存在的条件下,闭环系统是可镇定的,从而得到了常时滞分布参数系统可镇定的一个推论.最后,通过一个数值仿真例子说明了所给出设计方法的可行性和有效性.     

一种改进的网络控制系统控制器设计方法

讨论网络控制系统的状态反馈控制器设计问题。针对具有未知时变时延的网络控制系统,应用自由权矩阵方法得到系统的稳定性条件,并应用到具有时变结构不确定性的网络控制系统,在此基础上提出状态反馈控制器设计方法。数值实例表明该方法的有效性,与已有方法相比,具有较低的保守性。