Development of a climbing robot for inspection of long weld lines

Abstract

PurposeThe project Climbing Robot Cell for Fast and Flexible Manufacture of Large Scale Structures seeks to modernise and take into the future the technology of the manufacture of large fixed welded structures. It creates a transportable manufacturing cell consisting of a team of cooperating climbing robot work tools whose activities are coordinated and integrated through a central intelligence. The purpose of this paper is to present a wheeled robot, called NDT robot, designed for the real time inspection of long weld lines simultaneously with the welding process.Design/methodology/approachNeodymium permanent magnets are used for adhesion, which are capable of producing a maximum adhesion pressure of 4 × 104 Nm−2 at a 20 mm air gap. The strong neodymium magnets give the robot a high payload carrying capability. The arrangement of the magnet array increases its performance at large air gaps so that the robot has excellent capability to overcome obstacles, such as weld caps. The design of the wheeled robot with two sections jointed by a hinge joint has the advantage of high speed and good manoeuvrability, as well as working on curved surfaces and transferring between angled adjoining surfaces.FindingsThe NDT robot has been developed with the capability of climbing on steel walls carrying the specified payload and the ability to overcome the obstacles. The robot is also able to climb on curved surfaces with excellent manoeuvrability, and transfer between angled adjoining surfaces.Originality/valueThe arrangement of the magnet array enables the robot to retain a strong holding force at big air gap, so that the ability of the robot to overcome obstacles and work on curvatures is strengthened. The two‐section design improves the robot's performance on curvatures and enables it to transfer between angled adjoining surfaces.

Design of a climbing robot platform with protection device

“…The surface stiffness of airbag can be computed by solving equation (9). The pressure force distributed on the wheels can be solved by combining the surface stiffness of airbag with the negative pressure be measured to make quantitative processing to the pressure distribution and determine the distance between the airbag and the wheels.…”

“…The mechanical model of the surface stiffness of the airbag can be equivalent to the model of two springs in parallel according to equation (9), as demonstrated in Figure 15.…”

“…Equations (3) to (9) refer to the analysis of the surface stiffness of airbag. The surface stiffness of airbag can be computed by solving equation (9).…”

“…2,3 Therefore, climbing robots have been a very attractive research topic. There are a great number of potential applications to increase operational efficiency and protect human health and safety from hazardous tasks such as cleaning the facades of highrise buildings, [4][5][6] exploring natural and artificial environments, 7,8 inspection, 9 and so on. At present, many studies about techniques and applications of climbing robots at scientific research institutions have made significant achievements.…”

“…10 Unlike other robotic systems, the gravitational effect is so dominant that different approaches are required for the robot system to operate on the façade. 1 To overcome the gravitational effects, several studies have been conducted using various methods such as magnetic adsorption, 3,9,10,[11][12][13][14][15][16] biomimetic adsorption, 17,18 gripping type, 19 rail-guided type, 20 negative pressure adsorption, 21,22 and so on. Grieco et al developed a six-legged climbing robot prototype able to climb on ferromagnetic walls carrying high payloads available for inspection, maintenance, and intervention tasks in industrial environments.…”