The dynamic compliance composition of force-based impedance control and its experimental research

The bionic legged robot, driven by hydraulic, has a better ability to operate in different working environment. In order to prevent the robotic foot end from impact and collision during its contact with the ground, it is necessary to design the robotic joint with certain dynamic compliance. Generally speaking, the force based impedance control is a commonly adopted method for active dynamic compliance control in the legged robot's joints. The hydraulic drive unit(HDU), which actuates the joints' motion, is the research object in this paper. Thus, the dynamic compliance composition of force based impedance control is researched and analyzed. Then, aimed at the HDU, the theory of dynamic compliance serial-parallel connection is proposed through the mechanism modeling, equation derivation and theoretical analysis. Finally, the control effect of dynamic compliance control is verified experimentally on the HDU performance test platform. The experiment shows that the dynamic compliance control is capable of enhancing the system dynamic compliance for the HDU position control system and the theory of dynamic compliance serial-parallel connection is also proved. The experimental result contributes to improving the control performance of HDU force control inner loop.