New noise‐to‐state stability and instability criteria for random nonlinear systems

This paper investigates the noise‐to‐state stability and instability criteria for random nonlinear affine systems. Firstly, some new noise‐to‐state stability theorems, which weaken the sufficient conditions in the existing stability criteria on random nonlinear systems, are given by means of the uniformly asymptotically stable function. Secondly, the noise‐to‐state instability definitions are introduced and the sufficient conditions of noise‐to‐state instability are provided based on a new established lemma and the uniformly asymptotically stable function. Finally, some examples show the feasibility of theoretical findings.     

Operator‐Based Robust Right Coprime Factorization and a Nonlinear Control Scheme for Nonlinear Plant with Unknown Perturbations

This paper is concerned with operator‐based robust right coprime factorization for nonlinear plants with unknown perturbations. Firstly, the right factorization for by nonlinear plant with unknown perturbations is realized using isomorphism and some sufficient conditions are proposed to guarantee the robust stability of the obtained nonlinear feedback control system as well as the plant output asymptotically tracking to the reference input. Secondly, a quantitative control scheme is designed to satisfy the sufficient conditions. Finally, the effectiveness of the proposal is demonstrated by the simulation results.     

Global output feedback sampled‐data stabilization for upper‐triangular nonlinear systems with improved maximum allowable transmission delay

This paper addresses the problem of output feedback sampled‐data stabilization for upper‐triangular nonlinear systems with improved maximum allowable transmission delay. A class of hybrid systems are firstly introduced. The transmission delay may be larger than the sampling period. Then, sufficient conditions are proposed to guarantee global exponential stability of the hybrid systems. Based on these sufficient conditions and a linear continuous‐discrete observer, an output feedback control law is presented to globally exponentially stabilize the feedforward nonlinear system. The improved maximum allowable transmission delay is also given. The results are also extended to output feedback sampled‐data stabilization for lower‐triangular nonlinear systems. Finally, illustrative examples are used to verify the effectiveness of the proposed design methods. Copyright © 2016 John Wiley & Sons, Ltd.     

非线性时滞系统的稳定性分析及鲁棒稳定性条件

研究非线性时滞系统的稳定性.应用Lyapunov函数,分别讨论确定性和不确定性 非线性时滞系统.对于确定性系统,给出其零解渐近稳定的充分条件;对于不确定性系统,给 出其零解鲁棒稳定的充分条件.最后通过两个实例说明所给方法的有效性.     

非线性时滞系统的稳定性分析及 鲁棒稳定性条件1)

研究非线性时滞系统的稳定性.应用Lyapunov函数,分别讨论确定性和不确定性非线性时滞系统.对于确定性系统,给出其零解渐近稳定的充分条件;对于不确定性系统,给出其零解鲁棒稳定的充分条件.最后通过两个实例说明所给方法的有效性.     

NECESSARY AND SUFFICIENT CONDITIONS FOR DELAY‐DEPENDENT ASYMPTOTIC STABILITY OF LINEAR COTINUOUS LARGE SCALE TIME DELAY AUTONOMOUS SYSTEMS

This paper offers new necessary and sufficient conditions for delay‐dependent asymptotic stability of the linear continuous large scale time delay systems. The obtained conditions of stability are expressed by nonlinear system of matrix equations and the Lyapunov matrix equation for an ordinary linear continuous system without delay.     

On graphs, conic relations, and input-output stability of nonlinearfeedback systems

This paper presents necessary and sufficient conditions for the stability of general interconnected dynamical systems. The results are expressed in terms of the graphs of the interconnection's subsystems. Conditions for robustness of stability for an interconnection with additive disturbances are also provided. Finally, the paper gives sufficient conditions for stability using conic sector conditions that generalize earlier conditions and that incorporate a recent nonlinear small gain idea     

Robust Exponential Stability and Stabilization of a Class of Nonlinear Stochastic Time‐Delay Systems

This paper presents new exponential stability and delayed‐state‐feedback stabilization criteria for a class of nonlinear uncertain stochastic time‐delay systems. By choosing the delay fraction number as two, applying the Jensen inequality to every sub‐interval of the time delay interval and avoiding using any free weighting matrix, the method proposed can reduce the computational complexity and conservativeness of results. Based on Lyapunov stability theory, exponential stability and delayed‐state‐feedback stabilization conditions of nonlinear uncertain stochastic systems with the state delay are obtained. In the sequence, the delayed‐state‐feedback stabilization problem for a nonlinear uncertain stochastic time‐delay system is investigated and some sufficient conditions are given in the form of nonlinear inequalities. In order to solve the nonlinear problem, a cone complementarity linearization algorithm is offered. Mathematical and/or numerical comparisons between the proposed method and existing ones are demonstrated, which show the effectiveness and less conservativeness of the proposed method.     

On the exponential stability of switching diffusion processes

In this note, we investigate almost sure exponential stability for a class of switching diffusion processes. Lyapunov type sufficient conditions to ensure this type of stability for nonlinear switching diffusions are derived. The conditions are an improvement over related results in the literature, since they do not rely on the moment stability of the system. These conditions are then specialized to case of linear switching diffusion processes, to provide easily checkable sufficient criteria for exponential stabilization and robust stability.     

Sliding mode control design using canonical homogeneous norm

The problem of sliding mode control design for a nonlinear plant is studied. The necessary and sufficient conditions of quadratic‐like stability (stabilizability) for a nonlinear homogeneous (control) system are obtained. Sufficient conditions of robust stability/stabilizability are deduced. The results are supported with academic examples of sliding mode control design.     

Observers for Lipschitz nonlinear systems

This paper presents some fundamental insights into observer design for the class of Lipschitz nonlinear systems. The stability of the nonlinear observer for such systems is not determined purely by the eigenvalues of the linear stability matrix. The correct necessary and sufficient conditions on the stability matrix that ensure asymptotic stability of the observer are presented. These conditions are then reformulated to obtain a sufficient condition for stability in terms of the eigenvalues and the eigenvectors of the linear stability matrix. The eigenvalues have to be located sufficiently far out into the left half-plane, and the eigenvectors also have to be sufficiently well-conditioned for ensuring asymptotic stability. Based on these results, a systematic computational algorithm is then presented for obtaining the observer gain matrix so as to achieve the objective of asymptotic stability     

Robust nonlinear dynamic systems — The old question with a new answer

In this paper several upper bounds for parameter variations of a class of nonlinear (feedback) dynamic systems are presented. These sufficient conditions are used iteratively in a computer-aided algorithm to reach to the largest upper bounds or the stability robustness measure of such systems.     

Decentralized robust output feedback control for control affine nonlinear interconnected systems

In this paper, a scheme for decentralized robust control for control affine nonlinear interconnected systems using linear matrix inequalities (LMIs) is presented. Based on the Lyapunov theory, sufficient conditions for closed-loop stability of a nonlinear system, reference input tracking, and disturbance attenuation over its operating-range are obtained. Then, achieving these sufficient conditions are formulated as local LMI optimization problems. By solving the appropriately defined local problems, provided the obtained sufficient conditions are satisfied, the closed-loop stability, input tracking, and disturbance attenuation over the operating-range of the system are guaranteed. The designed controller is linear whose implementation is straightforward. An example is given to illustrate the proposed methodology.     

Stability and control of nonlinear systems described by retarded functional equations: a review of recent results

This paper reports on recent results in a series of the work of the authors on the stability and nonlinear control for general dynamical systems described by retarded functional differential and difference equations. Both internal and external stability properties are studied. The corresponding Lyapunov and Razuminkhin characterizations for input-to-state and input-to-output stabilities are proposed. Necessary and sufficient Lyapunov-like conditions are derived for robust nonlinear stabilization. In particular, an explicit controller design procedure is developed for a new class of nonlinear time-delay systems. Lastly, sufficient assumptions, including a small-gain condition, are presented for guaranteeing the input-to-output stability of coupled systems comprised of retarded functional differential and difference equations.     

Full‐Order and Reduced‐order Observer Design for a Class of Fractional‐order Nonlinear Systems

The paper is concerned with problem of the full‐order and reduced‐order observer design for a class of fractional‐order one‐sided Lipschitz nonlinear systems. By introducing a continuous frequency distributed equivalent model and using indirect Lyapunov approach, the sufficient condition for asymptotic stability of the full‐order observer error dynamic system is presented. Furthermore, the proposed design method was extended to reduced‐order observer design for fractional‐order nonlinear systems. All the stability conditions are obtained in terms of LMI, which are less conservative than some existing ones. Finally, a numerical example demonstrates the validity of this approach.     

Geometrically (Q,S, R)‐Incremental Dissipativity and Incremental Stability for Switched Time‐Varying Nonlinear Discrete‐Time Systems

This paper investigates geometrically (Q,S,R)‐incremental dissipativity and incremental stability for switched time‐varying nonlinear discrete‐time systems. A geometrically (Q,S,R)‐incremental dissipativity concept is proposed for switched nonlinear discrete‐time systems by using multiple storage functions and multiple incremental supply rate. Furthermore, the sufficient conditions of geometrically (Q,S,R)‐incremental dissipativity are given under the design of state‐dependent switching law. The incremental stability conditions are derived for geometrically (Q,S,R)‐incrementally dissipative switched systems. By designing of a composite state‐dependent switching law, the feedback interconnected switched systems are ensured to be geometrically (Q,S,R)‐incrementally dissipative. A numerical example is given to illustrate the validity of the proposed approach.     

基于模式运动的一类复杂生产过程的状态反馈渐近稳定性

针对基于模式运动描述的一类复杂生产过程的稳定性,给出了系统稳定的定义,提出了分析与判断系统渐近稳定的方法和充分条件.首先,介绍了基于模式运动的控制系统动力学描述方法.针对描述方法中的强非线性的分类、度量映射难以采用可运算函数描述的问题,推导并建立了相应的控制系统非线性状态空间模型.然后,利用李雅普诺夫稳定性理论研究了在状态反馈控制下时间离散、状态离散的非线性系统渐近稳定的充分条件,建立了系统输出的类别划分、状态空间模型的线性部分系统矩阵与系统渐近稳定的关系.最后,采用烧结机实际生产数据与非线性数值算例对该方法进行了仿真实验,结果验证了所提条件的有效性.     

Input‐to‐state stability of nonlinear stochastic time‐varying systems with impulsive effects

This paper considers the input‐to‐state stability, integral‐ISS, and stochastic‐ISS for impulsive nonlinear stochastic systems. The Lyapunov function considered in this paper is indefinite, that is, the rate coefficient of the Lyapunov function is time‐varying, which can be positive or negative along time evolution. Lyapunov‐based sufficient conditions are established for ensuring ISS of impulsive nonlinear stochastic systems. Three examples involving one from networked control systems are provided to illustrate the effectiveness of theoretical results obtained. Copyright © 2016 John Wiley & Sons, Ltd.     

Analysis and design of impulsive control systems

Some sufficient conditions for asymptotic stability of impulsive control systems with impulses at fixed times have recently been presented. In this paper, we derive some less conservative conditions for asymptotic stability of such impulsive control systems and the results are used to design impulsive control for a class of nonlinear systems. The class of nonlinear systems considered is also extended