Mobile Manipulation Using a Snake Robot in a Helical Gait
Belal A. Elsayed, Tatsuya Takemori, Motoyasu Tanaka, Fumitoshi Matsuno
Abstract
Snake robots have shown limited ability to perform manipulation tasks in comparison to their locomotion capabilities. In this article, we propose a mobile manipulation approach that increases the manipulation ability of snake robots by using their full-body motion. We consider a snake robot that moves along the outer surface of a pipe using the helical rolling gait. To perform a manipulation task, we extend the front links of the robot to form a manipulator-part, where the remaining links form a helical base that wraps around the pipe. In the proposed approach, the motion of the manipulator-part is combined with a rolling motion performed by the base-part. This results in enhanced rotational ability of the end-effector, without the need to install an additional rotary motor. The stability of the robot structure is also improved via the resulting tightening force between the helical base-part and the pipe. The kinematics of the proposed robot arrangement is represented considering a dynamically changing contact point between the links of the helical base and the pipe. To realize the proposed method, we introduce a two-level controller that enables the manipulator-part and the helical base to work simultaneously during manipulation. The experimental results showed the validity of the proposed method to track various trajectories and carry out manipulation tasks using a typical snake robot without extra actuators.