Handling implicit and explicit constraints in manipulation planning

Abstract

This paper deals with manipulation planning. The problem consists in automatically computing paths for a system composed of one or several robots, with one or several grippers and one or several objects that can be grasped and moved by the robots. The problem gives rise to constraints that can be either explicit – an object is in a gripper – or implicit – an object is hold by two different grippers. This paper proposes an algorithm that handles such sets of constraints and solves them in an explicit way as much as possible. When all constraints cannot be made explicit, substitution is operated between variables to make the resulting implicit constraint with as few variables as possible. The manipulation planning problem is modelled as a constraint graph that stores all the constraints of the problem.