Life Extending Minimum-Time Path Planning for Hexapod Robot

Abstract

This paper presents a minimum-time path planning scheme for life-extending operation of legged robots, illustrated with a six-legged walking robot (hexapod). The focus of this study is on extending the bearing fatigue life for leg joints. As a typical treatment, the minimum-time path planning is performed through a bisecting-plane (BP) algorithm with the constraints of maximum joint angular velocity and acceleration. Based on bearing fatigue life theory, its fatigue life increases while the dynamic radial force on the bearing decreases. By imposing more rigorous constraint on the dynamic radial force, the minimum-time path planning algorithm is thus revised by reinforcing the constraint of maximum radial force based on the expectation of life extension. A symmetric hexapod with 18 degree-of-freedom (DOF) is adopted as the illustrative example for simulation study. The simulation results validate the effectiveness of possible life extending with moderate compromise in transient performance.