Motion synchronization of HA/EHA system for a large civil aircraft by using adaptive control

Moving to more electric aircraft, a redundant configuration provide us an opportunity to introduce electro hydrostatic actuators into primary flight control system. Redundant mechanism produce a problem called force fighting (force difference b/w two actuators) that can damage aircraft control surface. This paper presents a model reference adaptive controller. Parameters of controller have been found with help of Lyapunov's stability theorem. Stability of controller is checked by using lyapunov's theory. Reference model is designed on the dynamics characteristics (rise time, settling time etc.) of hydraulic actuator. To assist the adaptive controller to improve synchronization and load rejection performance, a PID controller is used that takes force fighting as an input signal. This input signal is a measure of coupling effect. It is observed that adaptive controller not only completely removes initial force fighting but also it improves load rejection performance significantly. The whole design and experimental results have been done in MATLAB/Simulink.