3DCLIMBER: Climbing and manipulation over 3D structures

This paper describes the development of a novel pole climbing robot with the ability of climbing and manipulating across 3D structures, like petrochemical pipelines. The robot consists of a 4-DOF serial climbing mechanism and two grippers. Unlike many other developed pole climbing robots, 3DCLIMBER can overcome bends, T-junctions, flanges, and sharp changes on the pole’s diameter. With the current gripper, the robot can operate on circular profiles with diameters ranging from 200 mm to 350 mm and is able to scan the exterior surface of the pole. Existence of separate gripping and climbing modules allows application of various grippers for different profile shapes and sizes without any change on the climbing mechanism. In case of power failure the robot maintains its status without slipping on the structure. Furthermore, some nondestructive test operations require fine manipulation over the structure. Fine manipulation with an industrial arm encounters many well known difficulties. Such difficulties become even more problematic when the base of the robot’s arm is mobile. This problem was addressed by a robotic proprioception solution embedded into the robot by integration of inclinometers and range finder sensors as well as error compensation and self calibration algorithms. The proposed algorithms and sensors significantly improved the manipulation accuracy of the robot.

Research highlights
► Design and development of a pole climbing robot for inspection of 3D structures with bent section and T-junctions.
► Studying minimum degrees of freedom for the purpose.
► Climbing and manipulation over 3D structures with bends and branches.
► Increasing the manipulation accuracy by using interoceptive sensors: accelerometers and low cost IR range sensors.