SOSM Controller Design for Output Constrained Systems Subject to Disturbances With Unknown Magnitudes

This brief aims to develop a new second-order sliding mode (SOSM) control method for nonlinear systems subject to output constraints and disturbances with unknown magnitudes. First of all, the problem of output constraint can be solved by proposing a novel barrier Lyapunov function. Then, in order to handle disturbances with unknown magnitudes, we establish an integral dynamics. Based on these, the SOSM control algorithm can be constructed by using the technique of adding a power integrator step by step. The proposed SOSM controller can not only guarantee that the output variable keeps staying within the preset boundary but also deal with disturbances with unknown magnitudes. Finally, the validity of the control scheme is verified through an academic example.