Asynchronous Filtering for Discrete-Time Switched T-S Fuzzy Systems

In this paper, asynchronous H-infinity filtering is studied for discrete-time switched Takagi-Sugeno (T-S) fuzzy systems. New Lyapunov functions are constructed for switched systems with asynchronous switching between subsystems and candidate filters. These improved Lyapunov functions are dependent on the mode of filters instead of subsystems, which are more consistent with the switching mechanism of switched systems with asynchronous switching. Meanwhile, they are quasi-time-dependent, which are effective in achieving more general results than traditional time-independent Lyapunov functions. Based on the new Lyapunov functions, a stability and l(2)-gain criterion is deduced for switched T-S fuzzy systems. Then, switched fuzzy filters are designed to guarantee that the filtering error system is globally uniformly asymptotically stable and has a prescribed H-infinity performance. At last, an illustrative example is provided to demonstrate the potentials and advantages of the proposed filtering scheme.