Interval state observer for nonlinear switched systems with average dwell time

State estimation based on interval state observer is firstly considered for nonlinear switched systems with average dwell time (ADT) scheme, where the nonlinear vector functions are assumed to satisfy Lipschitz conditions. Then, based on the monotone system theory, an interval observer is designed to estimate state of nonlinear switched systems using the upper and lower observer variables. Finally, efficiency of the proposed approach is illustrated through a simple numerical example.