A study on parallel force/position control applied to hybrid electro-hydrostatic actuators

Hydraulic power systems and actuators play an important role in modern industry. In order to improve the control performance of electro-hydrostatic actuator (EHA), the aim of this paper is to propose a novel parallel control strategy named parallel self tuning Quantitative Feedback Theory (PSTQFT) to apply to control force and position of a new kind of hydraulic experimental system named electro-hydrostatic load simulator (EHLS). The PSTQFT controller is designed based on QFT technique for both the force and position control of the EHLS. Then the parameters of the PSTQFT force and position controller are automatically tuned online to minimize the system error by using gradient descent method and speed up convergence. Experiments are carried out to evaluate the effectiveness of the proposed parallel force and position control method applied to the EHLS system.