H∞ adaptive fuzzy control for high performance brushless drives

A new design method for a high performance brushless drive system employing both H-infinity optimal control design and fuzzy control design is described in this paper, The fuzzy control design is equipped with an adaptive learning algorithm to achieve H-infinity tracking performance with external disturbances. It gives elevation to the selection of optimal performance weights without any trial and error attempt. The objective is to establish a link between H-infinity optimal control design and fuzzy control design, so as to provide H-infinity tracking design with more intelligence and achieve better performance with fuzzy control design. In this study, the effect of both fuzzy logic approximation error and external disturbance on the tracking error is attenuated to an assigned level. The control strategy does not require explicit knowledge of the motor/load dynamics which is a useful feature when dealing with parameter and load uncertainties, The robustness of the proposed methodology is displayed for different types of trajectories. Simulation results suggest that the effect of both the fuzzy approximation error and external disturbance on the tracking error can be attenuated efficiently by the H-infinity adaptive fuzzy control. Accordingly, the proposed design method is suitable for the robust tracking control of the uncertain nonlinear drive systems and is an attractive control design philosophy. To the best of the author's knowledge, however, this control design represents the first such attempt for high performance drive systems.