Purpose This paper is concerned with non-fragile robust H∞ control problems for nonlinear networked control systems (NCSs) with time-varying delay and unknown actuator failures. The paper aims to discuss these issues. Design/methodology/approach The system parameters are allowed to have time-varying uncertainties and the actuator faults are unknown but whose upper and lower bounds are known. By using some lemmas, uncertainties can be replaces with the known values. By taking the exogenous disturbance and network transmission delay into consideration, a delay nonlinear system model is constructed. Findings Based on Lyapunov stability theory, linear matrix inequalities (LMIs) and free weighting matrix methods, the sufficient conditions for the existence of the non-fragile robust H∞ controller gain are derived and which can obtained by solving the LMIs. Finally, a numerical example is provided to illustrate the effectiveness of the proposed methods. Originality/value The introduced approach is interesting for NCSs with time-varying delay and unknown actuator failures.

The problem of non-fragile fault-tolerant guaranteed cost control is studied for a class of nonlinear networked control systems with time delays and packet dropouts. The system parameters are allowed to have time-varying uncertainties, and the actuator faults are assumed to occur in a random way. By utilizing Lyapunov stability theory and linear matrix inequality (LMI) methods, a sufficient condition for the existence of the H8 guaranteed cost fault-tolerant controller is derived, and then the desired non-fragile controller gain is obtained by solving the LMIs. Finally, a numerical example is provided to illustrate the effectiveness of the proposed method.

针对存在未知扰动、不确定性参数和时延的网络化控制系统,研究了执行器发生随机故障情况下系统的非脆弱容错镇定问题.通过引入范数有界不确定性参数描述控制器实现过程中的时变误差.利用Lyapunov稳定性理论和线性矩阵不等式分析方法,得到容错控制器存在的充分条件,求解线性矩阵不等式得到非脆弱容错控制器增益的参数表达式,数值仿真例子验证了控制器设计方法的有效性.