1994 Volume 7 Issue 5 Pages 185-191
A two-degree-of-freedom model following servosystem is proposed. First, a model following control system with no integral compensator is designed for a nominal plant, a given reference model, and a specified performance index. The obtained control system is augmented with an integral compensator. Then, additional feedforward and feedback are introduced at the output of the integrator to cancel the integral action for reference signals under the assumptions that there is no modeling error of the plant and no disturbance input to the plant. When the modeling error or the disturbance input exists, the integral effect appears so that the steady state error in the control output is eliminated.