Abstract: In view of the problem that the interference and nonlinear friction sensitively effect on flight simulators, an improved approximation differential compound control strategy with Equivalent Input Disturbance (EID) estimator is presented. Moreover, the setting conditions based on given parameters was proposed. In the presented strategy, the EID estimator can compensate the equivalent input disturbance of the system. Furthermore, owing to the construction of the digital feedforward via the improved differentiator, the improved approximation differentiator is able to acquire accurately the velocity and the acceleration of the signal, and has an ability to inhibit the partial noise by use of the improved. It avoids the disadvantage of the traditional differential method, which causes the amplification of the noise. Thus, the presented compound control strategy can improve the tracking precision and robustness of the system effectively. The simulation results show the effectiveness of the proposed method.

Key words: compound control, digital feed forward, equivalent input disturbance, flight simulator