PiROB: Vision-based pipe-climbing robot for spray-pipe inspection in nuclear plants

Abstract

Among many pipes in a nuclear power plant, the spray pipes in the reactor building are one of the most important pipes in view of their function and safety aspects. However, it is very difficult to manually reach and inspect the pipes for defects or damage, because these pipes are installed in very high places. To carry out this kind of inspection more easily, we developed a mobile robot to climb up and down and to cross over such pipes. A mobile robot should be small and light enough that it can be practically and safely operated in a nuclear power plant. Our robot is able to overcome obstacles such as valves, pipe flanges, and T-shaped branches, and it also meets the requirements of fail-safe, autonomous grasping, and self-power without the cables to the remote control station. The robot has a five-degree-of-freedom manipulator and two grippers and moves along the cylindrical pipes bypassing the obstacles. The robot should be able to grasp the next pipe autonomously, because the robot works in places high off the ground where the remote operator cannot see the next pipe for the robot to grasp. This article proposes a vision-based scheme for grasping a cylindrical pipe semiautonomously and describes its solution along with the forward kinematics and inverse kinematics of the mobile robot. The configuration of the pipe-climbing robot, including its hardware and software, is described, and the robot control with visual grasping is explained. The robot can be used practically for spray-pipe inspection as well as many potential other applications, such as inspection of the roof frame of a stadium consisting of pipes.

An Enhanced GRU Model With Application to Manipulator Trajectory Tracking

“…Hence introducing a high-efficiency and short latency solution for tracking robot manipulator motion is the burning issue [10,14]. Considerable approaches and technologies for tracking robot manipulator's motion have been comprehensively researched and introduced among the algorithms extended from general inverse kinematics [11], optimization theory [12], machine vision [13] as well as adaptive-control algorithms [10]. Traditional robot manipulator inverse kinematics solution has existed for several decades, but due to the multiple-solution and singular point, it could not perform well in continuous work.…”

Elastic Obstacle-Surmounting Pipeline-Climbing Robot with Composite Wheels

“…The robot could be adaptable to pipes with various diameters, radii of curvature, and inclinations. A pipe-climbing robot was proposed to inspect the reactor spray-piping system [17]. It had a five-DOF manipulator and two grippers and moved along cylindrical pipes like an inchworm, bypassing obstacles such as flanges and valves.…”

Development of a Mini Pole-Climbing Robot

“…Kim et al [5] proposed a robot that can climb up a spray-piping system located in a nuclear power plant's containment building. The robot has a five-DOF manipulator and two grippers and moves along cylindrical pipes like an inchworm, bypassing obstacles such as flanges and valves.…”

“…Based on the pole climbing robot's locomotion, the robot can be categorized into wheeled-based and grasping-based. The grasping-based climbing robot uses a claw or a gripper type mechanism to hold onto the surface; these include the works of [1,[3][4][5][6][7][8]. Meanwhile, the wheeled-based climbing robot uses wheels to contact the climbing surface; the robot moves when the wheels are rotating [2,[9][10][11][12][13][14].…”