Feedback control of a pipe cleaning snake robot with two helixes connected

In this study, we present a method for moving a snake robot in a pipe while generating slips between the robot and the pipe wall. This method is intended to be applied to pipe cleaning. The structure of the robot consists of a helix and reverse helix connected by a passive roll joint, and the rolling velocities of the two helixes are controlled differently to generate slips. We designed the target paths to ensure that the robot could clean the entire pipe wall even if the brushes were attached while spaced out. A feedback control that adjusted the rolling velocities of the two helixes to follow the target path was introduced. The position of the snake robot can be controlled to move independently in and around the pipe axis. We verify the effectiveness of the method using simulations and experiments. We confirmed that by using feedback control, the robot could roll according to the target path, but only in the backward direction of the robot. We also confirmed that applying this method to cleaning the entire pipe wall is difficult because of the different errors of each brush.