Fuzzy control of a nonlinear pointing testbed with backlash and friction

The pointing testbed is an experimental apparatus which can be used to examine the effects of nonlinearities, such as backlash and Coulomb friction, on the control performance. In this paper, a fuzzy controller is proposed to carry out high accuracy and fast positioning of the testbed. A reference model is utilized to obtain a smooth transient response and avoid undesirable overshoots. Through off-line simulation and on-line real-time implementation and test, the fuzzy controller is found to be capable of achieving an extremely high accuracy, a fast response and a good robustness against backlash and Coulomb friction