Gripper Design with Rotation-Constrained Teeth for Mobile Manipulation of Hard, Plating Corals with Human-Portable ROVs

Abstract

A mechanism for gripping onto plating scleractinian mesophotic corals is designed, realized and tested, with the goal of collecting samples via human-portable ROVs. Rotation-constrained teeth are employed to grip onto these thin structures which are abundant with surface ridges and asperities. Anisotropic contact conditions allow for gripper positional error on initial approach and grasping; the device can increase grasp engagement passively, allowing plate-like objects to be easily pushed into the gripper with forces on the order of 1 N. Yet, the gripper can resist large pull-out forces, tested up to 57 N in the lab. The gripper design is integrated with an ROV, and its capabilities are qualitatively evaluated in field tests. These trials confirm overall expected performance given real-world disturbances and variability. This cheap, additive-manufactured technology is being developed in an effort to make the ocean more accessible for scientific research.