Grasping of Cylindrical Structures Using an Underwater Snake Robot Without Force/Torque Sensors and Actuator Waterproofing

Abstract

This paper presents an underwater snake robot composed of submersible actuators designed for minimal friction, a lubricant-free gear reducer, and no waterproof sealing. This makes it suitable for direct exposure to water. In particular, this paper focuses on underwater interactive tasks with an object. Static force analysis for straightforward tasks, such as the wrapping of a pole structure, is conducted. Experiments were performed to evaluate the snake robot outside a water environment. The results indicated that the static model was valid, although the errors were not negligible. The potential of executing various tasks with this sensorless underwater snake robot, such as wrapping around the pole and its collection or turning on/off a lever underwater, is presented.