A Multi-link In-pipe Inspection Robot Composed of Active and Passive Compliant Joints

AIRo-5.1 an in-pipe inspection robot comprised of two passive compliant joints and a single active compliant joint that is driven by a series elastic actuator (SEA) is presented in the course of this study. As an aid in pipeline maintenance, AIRo-5.1 controls joint angles and the torque of middle joints, to enable them to adapt to bend, branch, vertical pipes, and slippery surfaces. To sense the joint torques, an improved durable polyurethane rubber spring was installed. To smoothly pass through T-branches, the angle trajectory of middle joints was calculated based on the pipe geometry and thus, was interpolated using a cosine curve. Experiments to verify robot performance in bent and T-branch pipes, its joint angle and torque control was conducted.