Comparison of classical PD and fuzzy PD controller performances of an aircraft pitch angle control system

Abstract

Aircraft dynamics are in general nonlinear, time varying, and uncertain. A control system (classical control systems) designed for a flight condition, may not provide the desired stability and performance characteristics in case of deviation from the equilibrium point. There are numerous studies regarding flight control in the literature. One of them is fuzzy flight control system Fuzzy Logic Controllers (FLCs) from their inception have demonstrated a vast range of applicability to processes where the plant transfer function is not defined but the control action can be described in terms of linguistic variables. FLCs are also being used with improved performance instead of "classical" controllers where the plant transfer function is known. Most of the applications about the design of fuzzy flight control are in simulation level. In this study, the design of classical and fuzzy PD controller for the pitch angle control system is analyzed and the results are compared for a very large, four-engine passenger jet aircraft.