On manipulating polygonal objects with three 2-DOF robots in the plane

Addresses the problem of grasping and manipulating a polygonal object with three disc-shaped robots in the plane. These robots may be the fingertips of a gripper or mobile platforms. The proposed approach is based on the characterization of the range of possible object motions when two of the effectors are fixed and the third one is allowed to move in the plane with two degrees of freedom. This technique does not assume that contact is maintained during the execution of the grasping/manipulation task, nor does it rely on detailed (and a priori unverifiable) models of friction or contact dynamics, but it allows the construction of manipulation plans guaranteed to succeed under the weaker assumption that jamming does not occur during the task execution. The proposed approach is validated by simulation examples and preliminary experiments with Nomadic Scout robots