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The purpose of this paper is to describe the design and prototype implementation of a miniature climbing robot with magnetic adhesion, developed for the inspection of gas turbines and other environments that require vertical mobility along curved steel surfaces, but only offer very narrow access holes – in the case of turbines only Ø15 mm.

After a detailed description and analysis of the industrial environment where the robot is supposed to be used (inspection of gas turbines, housing not opened), the paper describes the basic mechanical concept which is based on two traction units on magnetic wheels and a folding mechanism which allows the robot for changing between two configurations – one for passing through the narrow access holes and one for climbing with 2D mobility on curved surfaces. A special focus is put on how the most difficult design challenges were solved – torque transmission at this very small size and the design of the folding mechanism.

The feasibility of the concept is proven with a prototype implementation and successful test results.

Discussions with field service engineers at ALSTOM showed that gas turbines are relatively easy to open thus do not require access through the narrow bore‐scope‐holes.

However, in the field of boiler drum inspection, there is a need for such robots. The final industrial version of this robot, which is currently under development at ALSTOM Inspection Robotics, is optimized for this type of environments (more space but higher requirements regarding the robustness against shocks).

The robot concept presented here allows for accessing environments with very narrow access holes and afterwards climb with 2D mobility – an ability which opens several new applications for compact mobile climbing robots, especially in the field of power plant inspection.

The purpose of this paper is to describe the design and prototype implementation of a compact climbing robot with magnetic adhesion, which is only 8 mm high and allows for moving in any direction on the stators or rotors of power generators.

After a brief description of the industrial environment where it is supposed to be used (inspection of generator stators with the rotor still installed), this paper describes the basic mechanical concept, pointing to the core innovation and the advantages towards previous designs. The paper concludes with a prototype implementation and some test results; and provides an outlook on future extensions in the final industrial version.

Thanks to a new locomotion system based on flexible magnetic rollers (= magnetic wheels fixed on motorized flexible shafts; patented technology), the robot is able to span over gaps and non‐magnetic zones, both in axial and circumferential direction, while still being flexible enough for adapting to the large curvature of the rotor/stator (∼0.5 m‐2 m).

With this new design, it is now possible, for the first time, to access all types of large power generators (>100 MW) with only one device – while still keeping the mechanical complexity at a level which allows for realizing the robot in a robust way and at reasonable cost.