I. Introduction
Switched systems, a special class of hybrid systems, are composed of several subsystems and a switching law that decides when and which subsystem will be activated [1]. Switched systems have been a hotspot research recently on one hand for their various applications in the automotive industry, power train system [2], modern fermentation industry [3], switched-capacitor DC/DC power converter [4], traffic and aircraft control [5], and so on. On the other hand, some advanced theoretical results obtained from switched systems can be available in analyzing nonlinear systems [6]–[8]. So far, there have been many excellent results for stability of switched systems presented in [9]–[14].