Unknown input observer of a class of switched control systems

For a class of linear switched control systems (LSCSs) with unknown inputs, we study in this paper the unknown input observer (UIO) design problem. To design a full (reduced) order UIO, we first design for each subsystem a full (reduced) order UIO, and then we construct a full (reduced) order UIO for the whole system via picking the corresponding full (reduced) order UIO of the active subsystem according to the switching rule. Sufficient conditions for the existence of both full order and reduced order UIOs are derived. The design procedures of full order UIOs and reduced order UIOs are presented. Several stability results regarding to the state estimation error dynamics are established. Examples are given to show how to design UIOs for particular switched systems, and simulation results are given to show the effect of the designed UIOs.