Development of a Leg-wheel Mobile Robot using Switchable Permanent Magnetic Wheels for Bridge Inspection

In recent years, old bridges have increased and require inspection to detect any damaged parts and maintenance to decrease the risk of falling. Bridge inspection robots have developed rapidly to replace human labor. This paper presents a new development of an inspection robot using switchable permanent magnetic wheels rather than typical permanent magnetic wheels to control the adsorption force of each wheel, which can increase the maximum adsorption force of magnetic wheels compared to the previous design that needed to limit the adsorption force for successfully moving between surfaces. Furthermore, this robot has a total of six wheels that connect with leg structures to change its posture for moving to other surfaces on different paths. The movement process of the robot for changing the surface in each path is presented in this paper. As a result of the robot's performance, it can move and change to another surface in various paths and shows the potential to inspect the complex environment of the steel bridge.