Direct adaptive fuzzy control design achieving H/sup ∞/ tracking for high performance servo drives

Abstract

This paper proposes a direct adaptive fuzzy control technique to achieve H/sup /spl infin// tracking for high performance servo drives with external disturbances. The proposed methodology combines: the attenuation technique; fuzzy logic approximation method; and adaptive control algorithm for the robust tracking control design of the nonlinear servo drives with unknown parameter variations and structures. The adaptive fuzzy approximation technique is used as rough tuning and the H/sup /spl infin// disturbance attenuation technique is considered as fine tuning. Selection of suitable performance weights is the main problem in design of a robust H/sup /spl infin// controller. In this paper, a systematic and automated approach based on adaptive fuzzy logic algorithm is proposed. It gives elevation the selection of optimal performance weights without any trial and error effort. Computer simulations show the effect of both the fuzzy approximation error and the external disturbance on the tracking error can be attenuated efficiently by the proposed method. The results illustrate desired upgrade on both H/sup /spl infin// and fuzzy control design. Thus, the proposed technique is suitable for the control of the uncertain nonlinear servo drive tracking applications. To the best knowledge of the author, however, the H/sup /spl infin// optimal control design has not yet been used for adaptive control or fuzzy control of high performance servo drives.