Active screw-driven in-pipe robot for inspection

A novel active screw-driven in-pipe robot to inspect the condition of pipeline is proposed in this paper. The in-pipe robot consists of three parts, a suspension mechanism, four driving units and four electromagnetic brakes. Each driving unit includes a DC motor and a gear transmission train structure and the electromagnetic brake is used to switch the power transmission routine. Therefore, the DC motors can drive the wheels and also can steer the wheels with the help of the electromagnetic brake. Since the wheels have rolling motion and steering motion, the robot has translation motion, rotation and screw motion with respect to the axis of the pipe due to different position of the wheel steering angle. The robot can also overcome obstacles by using the screw motion mode and the compensation of the suspension mechanism. Furthermore, the relationship between the translation and rotation of the robot is investigated, simulation results shows that the steering angle can be treated as a regulator to adjust the moving speed of the robot besides its tuning the posture of the robot. Due the special moving principle, the robot can adapt circular and square tube without any change of the structure.