Locomotion System for a Mobile Robot on Magnetic Wheels With Both Axial and Circumferential Mobility and With Only an 8-mm Height for Generator Inspection With the Rotor Still Installed

This paper describes the locomotion system for a miniature climbing robot on magnetic wheels for inspecting large generator stators (> 1 m in diameter, > 10 MW, and installed in thermal power plants) with the rotor still installed. Due to its compact mechanical design, it is able to pass through narrow entrance gaps down to 9 mm. In comparison to previous designs, it is not only able to drive on axial paths on the stator but also switch to circumferential paths as well. This enhances the application scope to generators with internal obstacles and facilitates the future system integration toward fully autonomous scans. For the axial movement, the robot uses an adapted magnetic-wheeled drive unit from the previous generation. The circumferential paths are realized with inchworm locomotion (also called frame walking). This paper concludes with the test results and provides an outlook on future improvements and extensions toward a full robotic system.