Climbot-Ω: A Soft Robot with Novel Grippers and Rigid-compliantly Constrained Body for Climbing on Various Poles

Abstract

Soft climbing robots have been attracting increasing attention in soft robotics community, and a lot of prototypes been proposed with basic climbing function implemented. Climbing on poles is a challenge with soft robots, and the capability of current pole-climbing soft robots needs to be improved in terms of adaptability to various poles and deformation controllability or constraining of the soft body. In this paper, a rigid-compliant coupling or constraint method is proposed in design of pole climbing robots. Specifically, a novel gripper with inner expanding bubbles and a rigid-compliant belt is presented and designed, featured with excellent shape/size-adaptability and grip-reliability. To constrain undesired deformation of the soft body, rigid-compliant belts are also adopted. Three rigid-compliant constrained actuators are connected to implement an Ω-shaped deformation of the body for climbing motion. The kinematic feature of the body is established, and the two main features of the inner expanding gripper are analyzed. A series of experiments, where the robot climbs on poles with different shapes and sizes and in different poses, have verified the effectiveness of the presented rigid-compliant constraint and the shape/size adaptability and grip-reliability of the novel inner expanding grippers.