Abstract:  Aiming at the serious resonance problem of the electro-hydrostatic actuator caused by nonlinear friction, the electro-hydrostatic actuator was modeled as a dual inertial system and a resonance ratio control method was designed. Firstly, the working principle of the electro-hydrostatic actuator was studied, and the electro-hydrostatic actuator was modeled as a dual inertial system by using two high-stiffness inertial bodies connected by a low-stiffness shaft. Then, a feedback modulator was used to compensate the static friction of the actuator, and a resonance ratio control method including a feedback controller and an interference observer was designed based on parameter identification, which effectively suppressed the vibration of the actuator. Finally, the frequency response and position response were tested on a single-link manipulator experimental device. The results show that the double resonance phenomenon observed in the frequency response curve of electro-hydrostatic actuator verifies the feasibility of the proposed dual inertial system modeling. In addition, compared with the other two conventional proportionalintegral control methods, the maximum overshoot of the proposed resonant ratio control method is only 0.035 rad, and the average response error is only 0.005 rad, thus obtaining high-precision position response control performance, which having good reference value and application prospect in the research field of hydraulic transmission.

Key words:  electric hydrostatic actuator (EHA); resonance suppression; dual inertial modeling; feedback modulator; friction compensation

ZHANG Xiao-na, HU Meng-qian, TIAN Shan-shan. Double inertia modeling and high precision position response of electro-hydrostatic actuator［J］.Journal of Mechanical & Electrical Engineering, 2022,39(1):71-76.