Motion planning of a snake robot that moves in crowded pipes

We propose two motions for a snake robot to move through crowded pipes. One motion is an S-shaped twisting motion performed by the snake robot as it moves around crowded pipes in parallel to the pipes. To develop the shape of the snake robot, the S-shaped twisting motion creates large and small semicircles alternately. In the S-shaped twisting motion, lateral rolling is used to generate the robot's twisting motion along its body to maneuver among crowded pipes. The other motion is an S-shaped traveling wave motion used by the snake robot to move among crowded pipes perpendicularly to the pipes. The S-shaped traveling wave motion adds a hyperbolic shape to the snake robot by utilizing a hyperbolic function. The shape of the hyperbolic function produces a little wave in the S-shaped traveling wave motion, and the wave is transferred from the tail to the head to move ahead. In this study, we describe the design of these two motions and exhibit the results of trials in simulation and with a real snake robot to validate the effectiveness of our proposed snake robot's motion.