Hybrid Compliance Control for Locomotion of Electrically Actuated Quadruped Robot

Abstract

This paper presents a new hybrid compliance control system for a electrically powered quadruped robot leg composing both of active and variable passive compliance parts. The presented control system decouples the effects of each compliance type in a manner beneficial for the overall dynamics of the robot leg system. We investigate and demonstrate how the proposed hybrid compliance control of a mechanically stiff quadruped robot leg canimprove the performance of locomotion under moderate external disturbances. The observed robotic system integrates high gear ratio DC motors making the whole mechanism stiff and inconvenient for use when subjected to unknown disturbances, making this system a perfect candidate to implement compliance control. The variable passive compliance ensures the filtering of sudden impacts during locomotion while the active compliance allows lower bandwidth compliance control for locomotion purposes. Control system ensures that the joint effect of the active and variable passive compliance is fully controllable both in higher and lower frequency range. Mathematical modeling and simulation analysis is conducted in order to identify the performance of the proposed system. Finally, the system is experimentally validated from the single leg and quadruped robot perspective.