Force and position control of the integrated electro-hydraulic servo-drive.

Modern integrated electro-hydraulic servo-drives due to the complex integration of the hydraulic actuator, control valve, controller and sensors put high demands on their design and optimization. The integrated electro-hydraulic servo-drive (IEHSD) consists of a hydraulic actuator with position and force sensors. The hydraulic actuator (HA) is directly connected to a 4/3-way high response proportional directional control valve (4WRSE) with integrated axis controller (IAC). Integrated electro-hydraulic servo drives enable separate control of position, force and speed, combined force and position control, as well as control of motion synchronization of multiple drives. By synchronized motion control of integrated electro-hydraulic servo-drives, the trajectory tracking control of multi-axis manipulators with parallel structures is realized.