Devising a misalignment tolerant subsea grasping system

This paper addresses the problem of devising a subsea grasping system which tolerates significant pre-grasp misalignment between the gripper and its intended task object. We begin by discussing the desired characteristics and the required functions of such a system and use this information to select the most suitable approach for coping with misalignment. We present a 1-DOF gripper design and show that it accurately and repeatably locates cylinders of various diameters despite significant initial misalignment. We then present a handle design which, when grasped by a modified version of the gripper, also repeatably locates but requires no actuator torque to resist most manipulation loads. A suite of compatible, positively locating handles is presented, each imposing a different degree of constraint and each able to resist a different subset of manipulation loads. The paper concludes with a discussion of successful field testing of the system