On a sufficient condition for observability of nonlinear switched systems and observer design strategy

This paper presents a sufficient condition for observability of switched systems that involve state jumps and comprise nonlinear dynamical subsystems affine in control. Without assuming observability of individual modes, the sufficient condition is based on gathering partial information from each mode so that the state is recovered completely after some time. Using this result, an observer is designed which employs a novel ´back-and-forth´ technique to generate state estimates. Under the assumption of persistent switching, analysis shows that the estimate converges asymptotically to the actual state of the system.