Hydraulic Quadruped Robot Joint Force Control Based on Double Internal Model Controller

Abstract

In order to improve the servo accuracy of hydraulic quadruped robot electro-hydraulic servo actuators during operation, the load characteristic of equivalent model of electro-hydraulic servo actuators with swing phase and support phase was analyzed, respectively, the compound control strategy including flow compensator, velocity compensator, internal model controller, and improved internal model controller was proposed, the dynamic performance of system was guaranteed by internal model controller, the accuracy was further improvement by improved internal model controller. The composite control strategy was verified by robot single leg test platform, the experiment results show that the deviation and phase lag of response curve with flow compensation, velocity compensation and internal model controller was less than ±5% and 18°, respectively, the value of phase lag can be further reduced to 7°by the improved internal model controller, and the efficiency of the proposed control strategy was verified.