Sliding mode control design for mismatched uncertain systems using output feedback

For linear MIMO systems with mismatched parameter uncertainties along with disturbances and matched nonlinear perturbations, we consider the problem of designing an output feedback sliding mode control algorithm in this paper. The proposed output-dependent sliding variable can guarantee robust stability of the closed-loop system and obtain the property of disturbance attenuation once the system is in the sliding mode. The existence condition of the sliding variable is determined by solving the coupled algebraic Riccati equations which is involved with the original system parameters. The developed adaptive control law can guarantee that the system globally reaches and is finally maintained on the sliding variable in finite time. Finally, the feasibility of the proposed method is illustrated by a numerical example.