Research on testing platform for hydraulic legged robot joint control system

In order to test the control performance of the hydraulic legged robot joint control system, a hydraulic legged robot joint control system testing platform was developed. The mechanical structure, hydraulic system, and measurement-and-control system of the testing platform were introduced. In order to improve the force control performance of the load simulation system, a damping hole was connected in parallel between the two chambers of the load simulation cylinder, and a force PID control strategy with a position control signal feed-forward compensation was used. The simulation model of the testing platform was established in MATLAB/Simulink, and the simulation results showed that the load simulation system had good loading performance, and the two-stage supply pressure energy-saving joint control system had good control performance and energy-saving performance. Finally, the testing platform was applied to carry out the experimental research, and the results showed that: (1)The testing platform could realize the load force loading, whose frequency width was 3.5 Hz; (2) The control strategy with damping hole and feed-forward compensation used in the load simulation system reduces the root-mean-square error concerning the reference force by 62.11% compared to PID when performing hip load force loading; (3)The joint control system adopted the two-stage supply pressure oil source (TSS) of 15 MPa + 9 MPa, which could save 37.56% and 25.82% of the energy in tracking the planning trajectory of the knee and hip joints respectively, in comparison with that of the single oil source of 15 MPa.