CCRobot-IV: An Obstacle-Free Split-Type Quad-Ducted Propeller-Driven Bridge Stay Cable-Climbing Robot

This letter presents CCRobot-IV, the fourth version of a climbing robot designed for bridge cable-inspection tasks. CCRobot-IV inherits design features from the previous CCRobot series, and has improved capability for crossing cables with obstacles such as helical ribs, small metal accessories, and various other obstacles. CCRobot-IV consists of a quad-ducted propeller-driven climbing precursor and an affiliated payload-carrying body. Because a quad-ducted propeller does not depend on friction generated by mutual contact and extrusion, the precursor’s locomotion is decoupled from the surface of the bridge cable and the obstacles on it. When the precursor climbs up to reach the set position, it uses its gripper’s self-locking palms to grasp the bridge cable, which creates a fixed anchor point that allows the payload-carrying body to pull itself up using wires and two winches (which are a type of driving wheel that do not require extrusion force on the cable to produce adhesion and friction). Therefore, the robot’s payload capacity is also decoupled from adhesion to the cable surface, and thus the entire system has obstacle-free operation. Experimental tests and field tests have demonstrated CCRobot-IV’s climbing performance, payload capacity, and potential application utility.