Synchronous Position Control of Robotics System for Infrastructure Inspection Moving on Rope Tether

Most bridges, tunnels, dams, and other infrastructure facilities were constructed in the 1950s to 1960s. At present, aging in these facilities is a social problem. Most of the maintenance check-ups of these infrastructure facilities are manually conducted by close visual inspection, which has limitations. As a result, there have been many proposals on inspection systems for unmanned infrastructure facilities, such as drones and cable robots. However, there are also problems with the use of cable robots and drones, such as restrictions in places that they can be used and effects from the environment. Thus, this study proposes a robotics system for infrastructure inspection that solves such problems. Two robots move on parallel ropes stretching in an H shape, and one robot with a three-dimensional gimbal and camera moves on a rope stretching between those robots. At this time, the three robots are capable of efficient, highly accurate wide-ranging observation by carrying out synchronous position control using wireless communication. The control system has optimum synchronous position capabilities and uses a disturbance observer. Regarding this infrastructure inspection robotics system, this study discusses the development of three mobile robotics systems and the synchronous position control of two robots.