Abstract
This paper describes improvements to the mechanism and control of an in-pipe magnetic-wheeled robot. The robot has dual magnetic-wheels and can turn in a T-shaped iron pipe. However, the conditions for the turn are extremely restricted, that is, the robot must move within a certain tiny area of the pipe. To ease the conditions, a mechanism which allows the robot to twist in the middle has been successfully adopted. Meanwhile, it is very important to control the robot's movements in the area of the straight pipe before the turn. To guide the robot in the area, feedback controlling the angles of steering based on the angles of the steering and rolling is efficient. Futhermore, a Kalman filter is used to estimate the angle of steering. Sensing the angle of the twist is also an efficient way to compensate for the limitation of the sensor of the angle of rolling to improve robustness. An experimental robot has been successfully fabricated to confirm the efficiency of these ideas.
