Development of Lifting System for High-Elevation Inspection Robot Targeting Hanger Ropes

Abstract

In this paper, we show the development of a lifting system and frame body for an inspection robot targeting hanger ropes of a suspension bridge. Infrastructure now requires regular inspection and such robots are expected to be used in places where manual inspection is difficult. The problems associated with the lifting system for the hanger-rope inspection robot studied in this paper include a long lifting distance (up to 100 m), postural stability against the influence of wind, and risk of falling. To solve these problems, we propose a lifting system with an alternating rotation mechanism, which takes advantage of the lifting mechanism of a climbing doll. In this paper, we explain the design and control methods of the lifting mechanism and alternating rotation hoist to realize the proposed lifting system. For the moving frame body, we designed and made a mechanism and frame structure to maintain stability of its posture. Performing an operation test in our laboratory and in the field with the proposed system incorporated into an actual unit, we checked the action of the proposed mechanism. In particular, we could confirm in the field test that the postural stability necessary for shooting inspection images could be ensured in an environment with wind speed of 5 m/s and that ascending and descending motions could be successfully performed with the current output of the alternating rotation hoist, even in an environment with a mean wind speed of 10 m/s.