Robust Dynamic Integral Sliding Mode for MIMO Nonlinear Systems Operating Under Matched and Unmatched Uncertainties

In this research, a class of output feedback linearizable MIMO nonlinear systems is considered to be affected by both matched and unmatched uncertainties. The design of output feedback control law relies on an integral manifold, which permits subdivision of the control design architecture into two steps. In the first step, pole placement based continuous control component is designed, which regulates the system output when sliding mode is established. In the next step, a discontinuous control component is designed to cope with the uncertainties. In the proposed approach, the control input is applied to the actual system after passing through a chain of integrators. Consequently, the well-known chattering phenomenon, being caused by high frequency oscillations against the sliding manifold, is reduced and thus a continuous control input is fed into the system. This is a clear benefit in many applications, such as those of mechanical nature where a discontinuous control action could be inappropriate. The proposed control law is theoretically analysed and its performance in term of output regulation to zero is witnessed by the simulation results of two illustrative examples.