Impedance control of hydraulic series elastic actuation

The hydraulic system can provide a very large driving force and has high stiffness characteristics. System force control with high stiffness characteristics is very challenging. High-rigidity systems tend to oscillate when interacting with the environment and threaten the safety of the environment and the robot. The interaction between the robot and the environment is inevitable, so the problems of force control must be solved or improved. Obviously, reducing the stiffness of the system is a good solution. Series elastic actuation (SEA) can reduce the stiffness of the system. Therefore, choosing hydraulic SEA to achieve better force control. The dynamic response of the hydraulic system is rapidity and the dynamic response speed of the spring is slow. This article uses the method of impedance control. Through theoretical derivation and simulation verification, it is proved that the rigidity of hydraulic SEA is greatly reduced, and it has the ability of shock absorption and shock absorption.