Flow pulsation compensation based composite adaptive active disturbance rejection control for electro-hydrostatic actuators.

Abstract

Due to the residual pressure accumulated during the reciprocating movement of the plunger pump, there is a deviation between the flow pulsation and the theoretical calculation value. Current nonlinear control methods for the electro-hydrostatic actuator (EHA) often oversimplify and compensate for flow pulsation linearly, neglecting its nonlinear characteristics and deviation effects. This approach increases matching uncertainties and amplifies noise due to higher control gains, thus limiting the improvement of control performance. To address this issue, this paper proposes a composite adaptive disturbance rejection control method based on flow pulsation compensation for the EHA. This method equates the flow pulsation model of the pump to a combination of a theoretical flow pulsation control input term and a bounded disturbance term (the difference between the theoretical and actual flow pulsation), followed by the design of a composite adaptive law to handle parameter uncertainties, and the design of the expanded state observers based on position and pressure signals to estimate and compensate for the uncertainties nonlinearly. Finally, the effectiveness of the proposed method is verified by comparing with other control methods through experiments.