Dynamic Motion Planning Whole Arm Grasp Systems Based on Switching Contact Modes

We present motion planning for dexterous manipulation by whole arm grasp system based on switching contact modes. Motion planning for such a system should consider changing dynamics and kinematics according to the contact modes. We systematize the properties of the manipulation system by taking account of contact dynamics and kinematics, and derive the conditions to be satisfied in motion planning. The conditions give the restrictions of the feasible contact mode and the number of contact points. Noting that the manipulation system which involves continuous dynamics and discrete change of contact modes belongs to a class of hybrid system, we propose an algorithm of global motion planning based on a hybrid control perspective. We aim at finding a feasible joint torque trajectory and a sequence of contact modes to move the object to an object final state for given switching times and object state trajectory. The proposed planning algorithm mainly consists of planning the object trajectory by a randomized approach using an object nominal trajectory, and constructing subgoals which satisfy the proposed conditions by solving an inverse problem. We show the validity of the planner by simulating manipulation by whole arm grasp system.