A task planner for a dual-arm robot: A geometric formulation

Abstract

A dual-arm manipulator is necessary for many tasks that only a pair of human arms can do. The task planning effort, however, requires determination of the task specific arm movements which need not be unique for any given task. For example - pouring water from a jug to a cup can be executed in a variety of ways depending, perhaps, on the height of the cup and amount of water in the jug. The challenge, therefore, lies in the correct identification of the critical moves that are instrumental in execution of the task. A general task planning cannot merely be a path from an initial position to a final destination - which is rather relevant for pick & place tasks. We present here an approach to find the task specific maneuvers using the concept of virtual links. We imagine the task to be nothing more than the movements of invisible revolute and prismatic joints of a virtual robot which is connected to the arms of an actual manipulator. Using this approach we can find complex path that the manipulators have to generate in order to smoothly transit from one position-orientation (p, R) pair to another.