GTT

Fast climbing robots for environments made out of thin metal sheets

The original purpose of this project was the inspection of gas tanks in oversea ships. These expensive tanks have to be inspected regularly for leaks. For doing this, helium gas in inserted from the back and a sniffer probe has to be carried to every point in the tank to find the leaks. The current method using a tethered blimp was too slow and imprecise. Thus, the goal was to access these areas with climbing robots that attach to the surface. Using a state-of-the-art climbing robot was not possible due to the following restrictions:
- Low allowed mass, need for high speed  --> suction cups are not possible, magnetic wheels seem the only promising solution

- Thin sheet material                             --> the magnetic force is limited by saturation in the ground

- Difficult obstacles                               --> need for mechanisms to carry the wheels over the obstacles

We now developed a new inspection system that can solve all the challenges in this application. The main innovative ideas within this system are

- Separation into two robots: A big robot with high obstacle-passing capabilities carries a second one over the obstacles. This second robot is very simple, lightweight and fast and can drive on the fragile surfaces.

- Magnetic wheels that are specially optimized for thin surfaces

- Active structure that allows for passing ridge-type obstacles

The actual results are a detailed robot design for the whole system and prototype of the small robot, but the project is in standby for the moment.

Publications

Fischer, W., Tâche, F. and Siegwart, R. (2007) Inspection System for Very Thin and Fragile Surfaces, Based on a Pair of Wall Climbing Robots with Magnetic Wheels. In Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems. [IROS'2007] [pdf]

Fischer, W., Tâche, F. and Siegwart, R. (2007) Magnetic Wall Climbing Robot for Thin Surfaces with Specific Obstacles. In Proceedings of the 6th International Conference on Field and Service Robotics. [FSR'07] [pdf]

The research was funded by

GAZTRANSPORT & TECHNIGAZ, 1, route de Versailles, 78470 Saint-Rémy-lès-Chevreuse, FRANCE, A. Charoy and A. Mangé.