A micro mobile robot system for inspection between pipes

Industry inspection is an important emerging usage of microrobots. This paper presents the design, fabrication, control and performance of an omni-directional micro mobile robot, which is driven by three-phase electromagnetic micromotors. The microrobot has a volume of 9.5 mm x 9.5 mm x 9.5 mm, and includes three micromotors (5 mm in diameter) fabricated by micromachining and assembled manually. Two of them are used to actuate the wheels of micro robot. The other one controls the direction of wheels. In order to increase the torque and improve the rotational precision of direction micromotor, reduction gears, which have a reduction ratio of 3: 1, are assembled to change microrobot direction. And a novel closed control system of microrobot is described. The heart of drive circuit is MCU AT90S8515, which implements algorithm that allows the microrobot moves forward, backward and turns left, right or speeds up, slows down. Besides, control algorithm is designed to realize the microrobot performance. Experiments show that the microrobot can move successfully in the small spaces (15-20 mm) between pipes.