M. Chang et Pp. Lin, ONLINE FREE-FORM SURFACE MEASUREMENT VIA A FUZZY-LOGIC CONTROLLED SCANNING PROBE, International journal of machine tools & manufacture, 39(4), 1999, pp. 537-552
This paper presents a system and methodology for on-line free form sur
face measurement via a scanning contact probe installed on a CNC (comp
uter numerical control) machine. The scanning probe provides more samp
ling points than any traditional touch trigger type of probes used on
CNC machines, and better measuring accuracy than laser displacement se
nsing or structured lighting. The presented measuring system's main ad
vantage is that the number of measured points can vary with the change
of surface curvature. To improve the measuring stability and continui
ty, fuzzy logic control, in lieu of traditional PID control, is employ
ed. As a result, the system is capable of continuously detecting the b
oundaries of a measured object and measuring a relatively large comple
x surface. Based on the experimental results, the measuring accuracy i
s estimated between 20 and 30 mu m (micrometers). In addition to surfa
ce measurement, the reconstructed surface data can be fed to a CAD/CAM
system for component making or reproduction, which makes the reverse
engineering of models comprised of free form surfaces readily accessib
le. (C) 1998 Elsevier Science Ltd. All rights reserved.