An adaptive fuzzy control for AC servo system

Abstract

An adaptive fuzzy controller is developed for AC servo system to guarantee both global stability and performance. AC motor dynamics under consideration may include large nonlinear uncertainties, such as nonlinear load variations. The controller output method (COEM) is introduced and applied to the design of adaptive fuzzy control system. The method employs a gradient descent algorithm to minimize a cost function that is based on the error of the controller output. The cost function can be minimized through adapting some or all of the parameters of fuzzy controller. The proposed adaptive fuzzy controller is applied to a AC servo control problem and compared with a standard fuzzy controller. The simulation results show that the proposed control is effective and yields superior performance.