Trajectory based motion synchronization in a dissimilar redundant actuation system for a large civil aircraft

With the passage of time, the aircraft industry is moving towards more electric aircraft. This creates an opportunity to introduce dissimilar redundant actuation system in the primary flight control system. The problem arises, such as a force fighting (force difference between the outputs of actuators) in using dissimilar redundant actuation system. This paper presents a strategy to reduce force fighting for redundant actuation system of hydraulic actuator (HA) and electro hydrostatic actuator (EHA). A trajectory is designed on the basis of dynamic characteristics of the EHA. The feedback controller is used to improve load rejection performance and the two feed forward controllers to remove the initial force fighting between HA and EHA.