The modelling of the measuring point reproduction error for optical coordinate measuring machines

Abstract

Coordinate measuring machines (CMMs) are the most common measuring systems used for assessing the compliance of manufactured components with their geometrical specifications. Optical CMMs are currently gaining popularity as they enable fast and contactless measurement with accuracy almost as high as in case of tactile measurement. During the performing of measurement, the points at which the measurement is conducted are usually not exactly at the intended location, but due to different impacts (error sources), they are in the area surrounding this location. This paper presents a method for modelling the reproduction of point coordinates as probability ellipses geometrically limiting the area in which the actual measurement points may lie. Different mathematical algorithms for the description of these ellipses were examined and a discussion on the selection of the best method is presented in this paper.

Assessment of Background Illumination Influence on Accuracy of Measurements Performed on Optical Coordinate Measuring Machine Equipped with Video Probe

“…Works on development of a virtual model of optical CMM equipped with the video probe are now in the final stage in Laboratory of Coordinate Metrology. This model will be based on a description of the measurement uncertainty using multiple simulations of measuring points reproduction expressed as repeatability ellipses [ 24 ]. In order to make the virtual model fully functional, it is necessary to know two things: Values of task-specific error changes related to measurement of distances, positions and different form deviations under changing lighting conditions (needed for systematic error correction of single measurement result).…”