A robust internal model controller for nonlinear systems

A redesign of a control algorithm for nonlinear systems having the structure called internal model controller is proposed. This new controller, based on a Lyapunov stability technique, displays a better robust performance than the classical IMC structure. The controller is continuous, so it does not present chattering. Furthermore, a saturated, high gain observer is included to overcome the problem of needing full access to the plant state. Some experimental results obtained for the control of electric motors used as drivers of astronomical telescopes show the performance of the proposed control strategy.