Development of in-pipe operation micro robots

This paper describes a new in-pipe microrobot walking based on the principle of screw. The purpose to produce such a microrobot is to develop an in-pipe inspection working microrobot which can walk for more than 20 m in a pipe of 20 mm or less in diameter. The proposed robot is composed of several coil springs to connect the units; a unit has three twisted arms at every 120 degrees on the periphery, and a small rubber wheel is mounted on the outer end of each arm. Also, a small coil spring is set between the arm and the unit body to preload the wheel when the microrobot is placed in the pipe. When the robot is rotated in a small pipe by an external motor, it can walk about based on the principle of screw. The moving speed can be controlled by changing the rotational speed of the motor, and the moving direction can also be controlled by changing the rotational direction of the motor. The maximum moving speed is 100 mm/sec and the maximum traction load is 9.5 N