The design and development of Branch Bot: a branch-crawling, caterpillar-inspired, soft robot

Abstract

A soft climbing robot has the potential to access locations such as wiring ducts and tree canopies that are unreachable by humans and traditional rigid robots. In addition, a soft robot is robust and can fall without damaging itself or its environment. We present a soft, branch-crawling robot that is inspired by the passive gripping mechanisms used by caterpillars. The conformability of the robot’s soft body makes it uniquely suited to move in a complex 3D environment. A key innovation is that grip release is actively controlled and coordinated with propulsion generated by stored elastic energy. The robot is molded from silicone rubber and actuated using remote motor-tendons coupled to the structure through Bowden cables. Grip is achieved passively through an elastic flexure that pushes a compliant finger against the dowel. Experimental results show that the gripper is easily able to support the weight of the robot, and that the body structure allows the robot to crawl horizontally, vertically, and along branches. This robot demonstrates some key advantages of a soft robotic platform over traditional rigid robots.