Robust estimator design for switched systems with unknown switching time: An LMI-based approach

In this paper, a novel method for the design of a robust estimator for a class of switched linear systems subject to unknown inputs is presented. To consider a more general case compared to the literature, the switching sequence is assumed to be minimum average-dwell time but not available for measurement. To deal with this issue, the proposed estimator structure is divided into two blocks: mode-estimator and continuous-estimator. Based on this structure, a bank of robust estimators is designed for each block that is able to simultaneously estimate the active mode of the switched system and states. Using a common Lyapunov function, a sufficient condition in terms of linear matrix inequalities is derived, which guarantees the exponential stability of the estimation error dynamics. Simulation results illustrate the performance of the proposed robust estimator.