Co-simulation of a quadruped robot's mechanical and hydraulic systems based on ADAMS and AMESim

In order to observe the change and fluctuation in flow and pressure of a hydraulic quadruped robot's hydraulic system when the robot walks on trot gait, a co-simulation method based on ADAMS and AMESim is proposed. Firstly, the change rule in each swing angle of the hydraulic quadruped robot's four legs is analyzed and converted to the displacement change of the hydraulic cylinder by calculating their geometric relationship. Secondly, the robot's dynamic model is built in ADAMS and its hydraulic and control system models are built in AMESim. The displacement change of the hydraulic cylinder in the hydraulic system is used as the driving function of the dynamics model in ADAMS, and the driving force of the dynamics model is used as the loads of the hydraulic system in AMESim. By introducing the PID closed-loop control in the control system, the co-simulation between hydraulic system and mechanical system is implemented. Finally, the curve of hydraulic cylinders' loads, flow and pressure are analyzed and the results show that they fluctuate highly in accordance with the real situation. The study provides data support for the development of a hydraulic quadruped robot's physical prototype.