A pneumatic servo-motor (especially designed and developed in house) successfully replaces the need for an electric motor. All presently existing climbing robots use electric motors and thus have difficulty in conforming to the legislation for intrinsic safety. The present climbing vehicle, after slight modification, can easily fulfill the requirements of legislation for NDT instrumentation and equipment being intrinsically safe in hazardous environments. The vehicle can also achieve a rotational precision of 2 degrees which enables the climbing vehicle to reach locations with high precision.

The 3rd prototype system, not previously reported, allows an industry standard arm (PUMA 260) to be transported to a height of 30 metres consistent with a safety factor of 2 (ratio of maximum payload/PUMA arm mass+service umbilical mass). The system has overall dimensions of 1, 000 mm (length) x 750 mm (width) x 450 mm (height) and a mass of 35 kg.

The system performance is illustrated by c-scans of corrosion thinning with both wet (5 MHz) and dry (2.5 MHz) contact ultrasonic probes and the relative merits of these contact methods are quantitatively compared for various end user requirements (i. e. specification of minimum acceptable defect size).

Different types of NDT sensor, e. g., ultrasonic, eddy current, radiological, gas and optical, etc., can be deployed by the system with the payload (including the service umbilical) constraint of 30 kg with a safety factor of 2. REFERENCES

1. S. Chen, T. Sattar, A. Khalid and B. Bridge, "Climbing Robots-off the Shelf", Industrial Robot, Vol. 21, No. 5, pp. 27-30, 1994.
2. A. Khalid, S. Chen, T. Sattar, and B. Bridge, "Development of a Climbing Robot for the Deployment of NDT sensors in Hazardous Environments", the British Institute of NDT Journal, INSIGHT, Vol. 36, No. 12, pp. 943-948, 1994.