System calibration method for measuring head of coordinate measuring machine

Abstract

The invention provides a system calibration method for a measuring head of a coordinate measuring machine based on a master ball. The system calibration method comprises the steps of a) putting the standard ball with known radius R on a working platform of the coordinate measuring machine; b) installing the measuring head at a movable end of the coordinate measuring machine, controlling the coordinate measuring machine to move the measuring head according to a proper movement trajectory and completing the point scanning of the master ball on the working platform within a measurement range, wherein the point scanning approximately and uniformly covers the surface of the entire master ball to obtain N groups of data, N is larger than or equal to 200 and each group of data comprises the measuring point numerical value of the measuring head, the three-coordinate position reading of the coordinate measuring machine and the rotating angle of a gyrator; c) on the basis of the operation in the previous step, selecting partial data of the N groups of data, performing coordinate conversion, bringing the data into a spherical constraint equation and solving an over-determined nonlinear equation set by using an improved nonlinear least square method to obtain parameters to be calibrated and complete the system calibration.

Description

technical field [0001] The invention relates to a system calibration method for a measuring head of a coordinate measuring machine. Background technique [0002] With the development of modern industry and the progress of science and technology, many parts are miniaturized in size and freely complicated in shape. Due to the need for three-dimensional measurement of the free-form surface, in the actual measurement, the contact needs to constantly change the spatial position to complete the scanning of the sampling points, which greatly increases the difficulty and accuracy requirements of measurement and detection. [0003] In practical applications, because the three-coordinate measuring machine has the advantages of large measurable space, high precision and strong versatility, the coordinate measuring machine is often used to obtain the spatial position of the contact, and then further obtain the measured point of the free-form surface through coordinate conversion. Space...

AI Technical Summary

Problems solved by technology

However, this special optical probe is expensive and has low measurement accuracy, while the general-purpose one-dimensional optical probe is extremely difficult to install and adjust. It is difficult to achieve micron-level accuracy only by mechanical adjustment, which limits the application of optical probes.

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