Climbing robots for maintenance and inspections of vertical structures—A survey of design aspects and technologies

•Comprehensive state-of-the-art in climbing robots for maintenance and inspections.•Overview on locomotion and attraction principles for climbing robots.•Discussion and classification of requirements for commercial systems.•Schematics and design aspects of climbing robots.

The maintenance and inspection of large vertical structures with autonomous systems is still an unsolved problem. A large number of different robots exist which are able to navigate on buildings, ship hulls or other human-made structures. But, most of these systems are limited to special situations or applications. This paper deals with different locomotion and adhesion methods for climbing robots and presents characteristics, challenges and applications for these systems. Based on a given set of requirements these principles are examined and in terms of a comprehensive state-of-the-art more than hundred climbing robots are presented. Finally, this schematics is applied to design aspects of a wall-climbing robot which should be able to inspect large concrete buildings.