Joint Angle Control of an 8-inch Gas Pipeline Inspection Robot to Pass through Bends

Pipelines have been spreading in city areas around the world and the needs for inspection robots is increasing. Although many pipe inspection robots have been invented so far, most of them are manually operated when passing through bends or T-branches. Some studies have proposed pipe inspection robots that can pass through bends and T-branches by recognizing bending direction and adjusting its posture. However, only few studies described a concrete movement when the robot passes through bends or T-branches. In our research and development, an articulated pipe inspection robot that can move inside 8-inch gas pipelines has been proposed. In this paper, joint angles trajectories while the robot passes through a bend are presented. The joint angles are derived by using a geometrical relationship of the robot and pipe. By mathematizing the joint angles, a control system for passing through bends is implemented. Finally, the efficiency of the proposed control method was verified by experiments.