Kinematic Design and Prototyping of a Gripper With Grasping and Scooping Capabilities Driven by the Redundant Degrees of Freedom of a Parallel Robot

Abstract

A gripper design is adapted to offer grasping and scooping capabilities to a parallel robot. This enables the parallel robot to manipulate not only large objects, but also thin objects lying on flat surfaces. Moreover, this gripper is driven directly by the redundant degrees of freedom of the parallel robot to which it is integrated. Thus, by eliminating actuators from the gripper, weight is drastically reduced, thereby making it possible to take advantage of the full payload of the parallel robot. The kinematic architecture of the gripper is first presented, notably, the kinematic implications of using an epicyclic mechanism. Then, the kinematic model developed to integrate the gripper to a (6 + 3)-degree-of-freedom robot is presented. Trajectory planning strategies for both grasping and scooping are then presented together with the parameters used. Finally, the experimental validation of these manipulation methods is discussed briefly to assess foreseeable improvements to the gripper itself as well as the trajectory planning aspect of the manipulation methods.