Time delays exist in various types of systems that may cause system instability.The study of linear systems with time delays is of great significance.In order to study whether the time-delay systems are stable,stability criteria for such systems have been studied a lot.This article mainly studies the criteria for a class of time-delay systems.The specific contents are as follows:In the first part,this paper is concerned with the stability analysis problem of a linear system with time-varying delays.We use an improved triple-integral inequality and the reciprocally convex inequality to discuss sufficient conditions of asymptotical stability of a class of linear system with time-varying delays.A modified triple inequality is proposed first;then based on a newly introduced Lyapunov-Krasovskii functional,a stability criterion for the time-delay system is derived using the reciprocally convex inequality and the proposed triple-integral inequality.A numerical example shows that the proposed criterion is more conservative than some existing ones.In the second part,two cases of the time-varying delay are discussed,that is,the time-varying delay is either differentiable or just uniformly continuous,according to the linear systems with time-varying delay.First,an improved triple-integral inequality is proposed to estimate triple-integrals tightly.Then,by introducing two novel Lyapunov-Krasovskii functionals catering for two cases of time-varying delay,two sufficient conditions on stability,respectively,for the system under two cases of time-varying delay are derived using the improved triple-integral inequality and a necessary and sufficient condition on quadratic matrix inequalities reported recently.Finally,three numerical examples show that the obtained results outperform some existing ones. |