VISUAL CAD-BASED MEASUREMENT AND PATH PLANNING FOR FREE-FORM SHAPES

Iain Ainsworth, Mihailo Ristic and Djordje Brujic

Imperial College of Science, Technology and Medicine

Mechanical Engineering Department, Exhibition Road, London SW7 2BX, United Kingdom

Tel: (0171) 594-7048; Fax: (0171) 584-7239

(i.ainsworth, m.ristic, d.brujic)@ic.ac.uk

Abstract: Dimensional inspection of engineering components comprising free-form surfaces demands accurate measurement of a large number of discrete points, such that the actual shape may be fully characterised. This paper presents a methodology for measurement planning and collision-free probe path generation to perform measurement using a co-ordinate measuring machine. The measurement process involves the following main steps: registration, definition of measurement points, probe path generation, path optimisation and verification, and measurement. By employing the CAD model at every step, the implemented methodology maximises the measurement accuracy and achieves accurate control of the overall measurement process. In addition, the implemented tools for probe path simulation and verification provide a high level of confidence when dealing with complex engineering component geometry.