Dynamic hysteresis modeling and two-degree-freedom control with robust disturbance observer for piezoelectric rudder

Macro fiber composite(MFC)-driven rudder has advantage of low power,light weight and high reliability and has great application potential in UAVs.However,dynamic hysteresis nonlinearities in MFC reduce the control accuracy and stability.Flexible structure of MFC rudder is susceptible to external disturbance.In this article,a Hammerstein model is proposed to model the dynamic hysteresis nonlinearities of the MFC and the hysteresis inverse compensator is designed.Then,a 2 DOF controller with robust disturbance observer(DOB)is designed,which guarantees the robustness of the system under the external disturbance and model uncertainties.Finally,it is demonstrated by tracking control experiments of MFC rudder that the proposed controller has a good disturbance rejection and robustness and it improves significantly the control performance comparing with the conventional DOB. © 2019, Editorial Department of Control Theory & Applications South China University of Technology. All right reserved.