Akademiet for De Tekniske Videnskaber, Svejsecentralen

Peter Krarup

Svend A Lund

Thorkild Kristensen

In an improved method for determining the position of a measuring sensor or probe (1), such as a probe for ultrasonic examination of an object (2), use is made of at least two mutually crossing bars (3a, 3b, 3c) of electrically conducting material in constant sliding, electrical contact with each other. At least one bar (3a) is kept fixed in relation to the object (2) to be examined, and at least one bar (3b, 3c) is kept fixed in relation to the probe (1). By measuring the electrical voltage drops in the bars, the positions of the crossing points (4ab, 4ac) between these bars and thereby the actual position of the probe in relation to a reference system (x, y) on the surface of the object are determined. By using at least three bars, it is possible to determine the position coordinates (x, y) as well as the angular direction (v) of a freely movable probe in relation to objects to be examined having plane, cylindrical or double-curved surfaces. Since the method can be carried out completely without use of movable and, thereby, vulnerable and complicated mechanical or electrical elements, scanning systems based on the method can be made considerably smaller, simpler, cheaper and more robust and reliable in operation than systems hitherto known.

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Naerum, Denmark

Peter Krarup