Remotely controlled prehensile locomotion of a two-module 3D pipe-climbing robot

Most safety inspections of large piping structures are performed by humans. However, this approach requires considerable time and money and does not guarantee the safety of the inspectors. The proposed pipe-climbing robot is designed to move on the outside of large pipe structures and perform non-destructive inspection in place of human inspectors. Required to negotiate external obstacles such as fixtures, flanges, and valves, as well as pipe components such as elbow and T-branch joints, the proposed pipe-climbing robot comprises two driving modules and an actuated connecting arm. By working together, the two driving modules overcome the various obstacle components in a pipeline network. The wheel-driven locomotion mechanisms of the system also enable it to move quickly along the pipeline. A strain gauge is attached to the climbing arm to confirm the grasping state of the robot on the pipe. The robot is designed to attach stably to a pipe, which features a very low backlash, by means of worm drive and ball screw mechanisms. Experiments show the ability of the robot to grasp stably on a pipeline and climb the pipeline at a speed of 18 cm/s.