Design of High Efficiency Bio-inspired Hydraulic Actuator for Wearable Robotic System

Inefficiency is a technical bottleneck that affects the widespread use of wearable robots. Inspired by the efficient motor mechanism of human muscles, we designed a high efficiency Bio-inspired Hydraulic Actuator (BHA) that combines pump, cylinder, valve and motor in a compact structure. By mimicking the structure of the multi-fiber motor unit and the power supply mode of human muscles, the new actuator adopts a two-stage energy supply mode and an innovative structure of two pumps and two cylinders. Through such a design, the output power and force of the BHA can precisely match the change of load, reducing the throttling loss in the traditional hydraulic system and greatly improving the system efficiency of the bionic wearable robot. The analysis and experiments in this paper show that the actuator of the integrated pump cylinder has good energy efficiency, and the prosthesis using BHA can achieve a gait consistent with human normal walking.