Development Of High Performance Hydraulic Joint Drive System For Walking Robot

Electro-hydraulic driving technology has the advantages of high power density, high control precision and fast response speed, which is suitable for the application in robot joint drive. The high speed walking robot which is being developed by our laboratory also uses the driving mode. Therefore, it is necessary to develop a high performance hydraulic drive system to meet the need of high speed walking.Firstly, this paper introduces the design of the hydraulic drive system of the robot, including the design and optimization of the hydraulic drive system and the swing hydraulic cylinder.Secondly, this paper builds the transfer function model of the valve-controlled of electro-hydraulic position servo system and the corresponding Simulink model by taking the knee joint of the robot as research object. With the Simulink modet, it finishes the PID controller design, analyzes influences of control parameters of the PID controller and nonlinearities on the system performance.Thirdly, the software and hardware design of the hydraulic drive system of the robot is completed, which makes the whole system have the functions of control, drive, sensing and so on. And the control algorithm of the system is based on the incremental digital PID control.Finally, the swinging hydraulic cylinder and hydraulic drive system performance testing and verification experiments are done. The dead zone, seal efficiency and bandwidth of the swing hydraulic cylinder are tested in the experiment. Through the analysis of experimental results, we find that, the performance of swinging hydraulic cylinder significantly improved compared to last generation and the hydraulic drive system has good control performance, which can satisfy the requirements of high-speed walking robot drive system.