Design and Experiments of Electro-Hydrostatic Actuator for Wheel-Legged Robot with Fast Force Control Response

The wheel-legged robot combines the functions of wheeled vehicles and legged robots: high speed passability. However, limited performance existing joint actuators has always been bottleneck in actual applications large robots. This paper proposed a highly integrated electro-hydrostatic actuator (EHA) to enable high-dynamic giant robots (>200 kg). A prototype with force-to-weight ratio was developed by integrating micropump, miniature spring accumulator, micro-symmetrical cylinder. achieves output force more than 9400 N 2518 N/kg. Compared EHA-based robots, it higher can bear larger loads. detailed EHA model presented, controllers were designed based on sliding mode control PID methods position piston. model’s accuracy is improved identifying uncertain parameters such as friction leakage coefficient. Finally, both simulations experiments carried out. results verified fast response (step within 50 ms, tracking frequency about 6.7 Hz) EHA’s good potential for future