Autonomously clearing obstacles using the biological flexor reflex in a quadrupedal robot

Abstract

SUMMARY This paper suggests one possible mechanism for the biological flexor reflex by emulating a cat's behavior with its robotic counterpart, making it capable of walking around and clearing obstacles autonomously in various environments. A central pattern generator and a hip-to-knee mapping function are employed to realize basic rhythmic motion for a quadrupedal robot. When an input from a contact sensor on the robot's toe is detected, a patterned motion generated by the flexor reflex emerges depending on the location of the bumping phase, and replaces the ongoing rhythmic motion of that leg, causing it to be raised high enough to clear the obstacle. By restricting this reflex to within one cycle time of the walk and only to the bumping leg, rhythm and stability of motion are ensured. Numerical simulations and experimental implementation on a physical quadrupedal robot demonstrate the effectiveness of the proposed method.