Design of a Growing Robot Inspired by Plant Growth

A novel design concept of expandable robotic arm inspired by plant growth is presented. The robot can construct its own structure by converting a type of fluidized material into a rigid structure at its growing point. The robot can extend its structure in multiple directions, and move through a winding space to reach a point, which is otherwise difficult to access. The robot with the rigid structure can also bear a significant load, has a plate to attach an end-effector, and can transport an object. The robot satisfies three key functional requirements that are characteristic to plant growth. First, the robot is capable of transporting structural materials to its growing point. Second, the robot is capable of transforming the material into a rigid structure. Third, it is capable of steering its growing point so that it is expanded in a desired direction. A proof-of concept prototype is then presented that consists of a special sprocket chain that can be switched between flexible/fluidized and rigid states, a winch that can pull/transport the chain, and a steering system to direct the growing direction. Unlike plants, this growing robot can retract its extended body, and can extend in a different direction. The prototype demonstrates that it meets all the functional requirements, and that it can make sharp turns and move through obstacles.