An Effective Fuzzy PD Control for High Precision Servo Mechanisms

This paper addresses the design of a fuzzy PD control in the presence of hard nonlinearities for high precision servo mechanisms. Its effectiveness relies on the practical success of popular fuzzy PD control and robust control design techniques. The proposed control consists of a conventional fuzzy PD and a robust compensation component. The fuzzy PD control uses the tracking error and its derivative to generate a control action according to an expert experience. The design of this fuzzy control also gives a linear parametrization that allows the design a "plug-in" robust control component aimed at increasing the tracking performance. Instead of assuming a model for nonlinearities or a bound on their effects, this robust fuzzy PD control is designed relying on the fact that PD-type controls can yield an acceptable tracking performance, a compensation is required only for the purpose of improving the tracking accuracy. Simulation and experiment results are included to illustrate the proposed control