Design and tracking control of an electro-hydrostatic actuator for a disc cutter replacement manipulator

Abstract

The development of the disc cutter replacement manipulator requires an actuator with high power density and excellent positioning precision, typically, electro-hydrostatic actuator (EHA). However, the EHA is a pump-controlled hydraulic system that has a slower response in comparison with conventional centralized hydraulics. In this paper, a position-pressure feedback control (PPFC) method is proposed to improve the system response and position accuracy. Experimental verifications showed that the suggested control method can shorten the time delay by 70.08% in the direction of positive-load movement when compared with traditional position feedback control methods, and the presented EHA can reach a precision of 0.001 mm while moving a load of 1.5 t. This enables the actuator to follow higher frequency target trajectories under heavy load with high positioning accuracy. In order to achieve better automatic control, the PPFC strategy could be combined with other controllers such as adaptive controllers.