A Double-jaw Hand that Mimics A Mouth of the Moray Eel

Abstract

In this paper, we develop a gripper by mimicking the pharyngeal jaw of a moray eel to perform assembly tasks. A moray eel has two sets of jaws called the oral jaw (the main jaw) and the pharyngeal jaw (the smaller jaw). The pharyngeal jaw is mobile, which means it is able to go forward or backward relative to the oral jaw. By likening each jaw as a two-finger parallel gripper, we develop a bio-inspired robotic hand with similar structure, which we call a double jaw hand. The two parallel grippers in the double jaw hand are connected by a prismatic joint on a common approaching vector. Similar to moray eels, the double jaw hand is able to hold objects using the outer gripper and hand over them to the inner gripper (inspired by how a moray eel captures and swallows objects). Also, it is able to assemble and disassemble industrial parts (inspired by how a moray eel cuts its prey). Several experiments are performed to demonstrate the design and the abilities.