Switched observer design for a class of locally unobservable time-varying systems

Abstract We consider the problem of state estimation for a parameter-varying system that is unobservable for some values of time-varying parameters. The set of parameter values is divided into a finite number of subsets for which the system is observable, and a switched observer is proposed. A dwell-time condition is defined that ensures exponential convergence. The conditions of stability are formulated in the form of matrix inequalities, which can be used for gains tuning. The obtained theoretical results are supported with an illustrative example and experimental studies for a reaction-wheel pendulum testbench.