Sensors, Vol. 20, Pages 5592: A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System

Sensors, Vol. 20, Pages 5592: A CMM-Based Method of Control Point Position Calibration for Light Pen Coordinate Measuring System
Sensors doi: 10.3390/s20195592
Authors:
Sen Wang
Shugui Liu
Qing Mao

A light pen coordinate measuring system (LPCMS) is a kind of vision-based portable coordinate measuring technique. It implements coordinate measurement by analyzing the image of a light pen, which has several control points and a probe. The relative positions of control points need to be determined before measurement and serve as the measuring basis in LPCMS. How to accurately calibrate the relative positions of control points is the most important issue in system calibration. In this paper, a new method of control point position calibration based on a traditional coordinate measuring machine (CMM) is proposed. A light pen is fastened to the measuring arm of a CMM and performs accurate translational movement driven by the CMM. A camera is used to capture the images of control points at different positions, and the corresponding readings of the CMM are recorded at the same time. By establishing a separate coordinate system for each control point, the relative positions of the control points can be transformed to the differences of a series of translation vectors. Experiments show that the calibration repeatability of control point positions can reach 10 μm and the standard deviation of measurement of the whole LPCMS can reach 30 μm. A CMM is used to...

Source: Sensors - September 28, 2020 Category: Biotechnology Authors: Sen Wang Shugui Liu Qing Mao Tags: Article Source Type: research