Whole-Body Motion Planning for Walking Excavators

This article presents a trajectory planning framework for all-terrain vehicles with legs and wheels such as walking excavators. Our formulation takes into account the whole body of the robot while computing the plans for locomotion. Hence, we can produce motion plans over the rough terrain that would be hard to plan without considering all Degrees of Freedom (DoF) simultaneously. Our planner can also optimize over the contact schedule for all limbs, thereby finding the feasible motions even for the infeasible initial contact schedule. Furthermore, we introduce a novel formulation of the support area constraint. We generate plans for a Menzi Muck M545, a 31 DoF walking excavator with five limbs: four wheeled legs and an arm. We show motion plans for traversing a variety of terrains that require whole-body planning. To the best of our knowledge, this is the first work that addresses motion planning in rough terrain for vehicles with legs and wheels.