Robust gain scheduling method based on fuzzy logic control and LMI methods

Abstract

In this paper, a practical gain-scheduling control law to consider robust stability and performance of systems with nonlinearity and uncertainty is presented. The method is based on Linear Parameter Varying(LPV) systems which result in a controller which is scheduled with time-varying parameter describing possible dynamics of the plant. The proposed method introduces LMI-based pole placement synthesis to consider the robust stability and performance with respect to structured uncertainties. For the robust stabilization of gain-scheduled controller, it also utilizes recently developed fuzzy control system which is based on Takagi-Sugeno’s fuzzy model. Then, the sufficient conditions for robust controller design of linearized local dynamics and robust stabilization of fuzzy control systems are reduced to solve a finite set of Linear Matrix Inequalities(LMIs), and they are solved in conjunction with co-evolutionary algorithm which is developed to solve saddle-point problems. For the validity and applicability of this method, this paper develops a gain-scheduled longitudinal controller for a high performance aircraft and demonstrates linear and nonlinear simulation results.