Compensation for dynamic errors of coordinate measuring machines

• Published in: Measurement : journal of the International Measurement Confederation 1997-03, Vol.20 (3), p.197-209
• Main Authors: Weekers, W.G., Schellekens, P.H.J.
• Format: Article
• Language: English
• Subjects: Coordinate measuring machine; Dynamic errors; Error compensation; Error modelling; Exact sciences and technology; Fast probing; Inductive position sensors; Measurements common to several branches of physics and astronomy; Metrology, measurements and laboratory procedures; Physics; Spatial dimensions (e.g.: position, lengths, volume, angles, displacements, including nanometer-scale displacements); Spatial dimensions (eg, position, lengths, volume, angles, displacements, including nanometer-scale displacements)
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/S0263-2241(97)00032-8

Owing to the demand for shorter cycle times of measurement tasks, fast probing at coordinate measuring machines (CMMs) has become more important and therefore the influence of dynamic errors of CMMs will increase. This paper presents an assessment of dynamic errors owing to carriage motion, aimed at error compensation. In the adopted approach the major joint deflections as a result of accelerations are measured with position sensors. Other joint deflections are estimated based on analytical modelling of CMM components. Using a kinematic model of the CMM, the influences of the measured and estimated joint deflections on the probe position are calculated. The dynamic errors can be corrected by software compensation, based on the calculated values. The approach has been applied to an existing CMM, using inductive position sensors for on-line measurement of the major dynamic errors. Experiments show that the compensation method is very successful, enabling fast probing without serious degradation of measurement accuracy.