A model-reference variable structure controller based on a high gain observer (HGO) is proposed and analyzed. For single-input-single-output plants with relative degree larger than one, the switching law is generated using the observed state while the modulation function in the control law is generated using signals from state variable filters. With this scheme, global exponential stability with respect to an arbitrarily small residual set is achieved. Moreover, the closed loop system shows no peaking phenomena which could degrade the performance. Experimental results illustrate the good performance obtained with the algorithm in actual conditions.
Sliding mode; Variable structure; High gain observer; Reference-Model
