Backstepping adaptive control of dual-variable electro-hydraulic actuator with displacement-pressure regulation pump

Electro-hydraulic actuator(EHA) with variable rotational speed fixed displacement pump or fixed rotational speed variable displacement pump flow regulation has been very common. But these two kinds of EHA need to be improved in heating and response characteristics. The dual-variable EHA system with variable rotational speed motor and variable displacement pump regulated by pressure not only has a great advantage in reducing the heating problem, but also can effectively improve the dynamic characteristics of the system. In this paper, the displacement control method of this kind of EHA pump is studied, and the electro-hydraulic proportional pressure reducing valve is used to the pressure in displacement-controlled cylinder. When the EHA load is large, the load torque acted on the electric-motor shaft will be not increased because of the regulation of pressure-displacement variable pump, thereby reducing the current and heating of the motor. In this paper, the backstepping adaptive control method is used to overcome the uncertainty of the hydraulic system. The simulation results show the effectiveness of the control approaches.