Modeling, analysis and simulation of an electrohydraulic flight control actuation system including friction

Abstract

Electrohydraulic servosystems are commonly employed to actuate flight control surfaces in aircraft, particularly in military aircraft. They are increasingly used in commercial aircraft to minimize pilot effort and to provide easy interface to flight control computers. In many of the applications the servoactuator is connected to a flight surface (load) through a compliant member that introduces additional dynamics. This paper addresses some of the issues related to the modeling of these kinds of systems, particularly the effect of friction in the actuator, and its effects on system performance. This paper also outlines approaches that can be adopted to reduce the effect of friction on system performance.