A compound control scheme for aircraft nose wheel steering load system

Steering mechanism is a vital component of aircraft nose wheel steering system. In order to checkout its reliability and working period, repeated loading test is a necessity which is used to simulate friction between wheel and ground before putting it into application. In the test, for meeting the requirement of loading precision, high tracking performance of position servo system used for controlling of steering angle is also required, which increases the difficulty of controller design inevitably. Aiming at addressing this problem, a compound control scheme is proposed in this paper. On the one hand, backstepping nonlinear control method is employed to guarantee the tracking accuracy of steering angle. On the other hand, PID combined with feedforward controller is developed for assuring loading precision. Results of simulation show that the proposed approach is feasible which can meet fully requirements of testing system.