MIMO sliding fuzzy type-2 control with manipulating approaching phase

A sliding fuzzy type-2 controller scheme for multi-input multi-output (MIMO) nonlinear uncertain perturbed systems is proposed in the paper. To overcome the constraint on the knowledge of the system model, local models related to some operating points were used to synthesize a nominal fuzzy type-2 global model. The controller uses integral sliding mode concept and contains two parts. The first one leads to achieve finite time stabilization of the higher order input output dynamics without uncertainties. The second part has the object to reject bounded uncertainties throughout the entire response of the system. In order to eliminate the chattering effect, the sign functions in this part control are substituted by a smooth variation functions. Their structures retain the characteristics of the original functions. The sliding sub-surfaces are computed using a generalized Slotine equation, this choice leads to reduce the relative degree of the system to one, which simplifies the design of the proposed method. The advantages of the controller are that its implementation is easy, the convergence time is chosen in advance and the robustness is ensured. Simulation results of two link robot manipulator are presented to illustrate the tracking performances of the method.