Measurement method for geometric errors of numerical control turntable based on four-station laser tracer system

US11543234B2 · kind B2 · utility

Assignee

• XI'AN JIAOTONG UNIVERSITY · CN

Inventors

• Jun Zha · Lo Wu, CN
• Yaolong Chen · Aalen, DE
• Lin Han · San Jose, US

Key dates

• Filing date: Aug 28, 2020
• Grant date: Jan 3, 2023
• Expiry date: Mar 4, 2041

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B23Q2220/004
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method for measuring geometric errors of a numerical control turntable based on a four-station laser tracer system includes: establishing a self-calibration coordinate system and calibrating positions of tracking interferometers; respectively placing each of target lenses at three non-coplanar points that are above the numerical control turntable and keep certain distances from the numerical control turntable, controlling the numerical control turntable to rotate at a certain angular interval θj, and based on positions of the tracking interferometers being known after calibration, solving coordinates of each of measurement points in the self-calibration coordinate system using a non-linear least square method; establishing a turntable coordinate system; perform a conversion between the turntable coordinate system and the self-calibration coordinate system; separating six geometric errors of the numerical control turntable using spatial position errors of the three points at a same position and using the linear least squares method.