Least Squares Evaluations for Form and Profile Errors of Ellipse Using Coordinate Data

作     者：LIU Fei XU Guanghua LIANG Lin ZHANG Qing LIU Dan 

作者机构：School of Mechanical Engineering Xi'an Jiaotong University State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing SystemXi'an Jiaotong University 

出 版 物：《Chinese Journal of Mechanical Engineering》 (中国机械工程学报（英文版）)

年 卷 期：2016年第29卷第5期

页      面：1020-1028页

核心收录：

学科分类：08[工学] 0804[工学-仪器科学与技术] 

基　　金：Supported by National Natural Science Foundation of China(Grant No.51575438) 

主　　题：ellipse form Error profile error least squares method piston 

摘      要：To improve the measurement and evaluation of form error of an elliptic section, an evaluation method based on least squares fitting is investigated to analyze the form and profile errors of an ellipse using coordinate data. Two error indicators for defining ellipticity are discussed, namely the form error and the profile error, and the difference between both is considered as the main parameter for evaluating machining quality of surface and profile. Because the form error and the profile error rely on different evaluation benchmarks, the major axis and the foci rather than the centre of an ellipse are used as the evaluation benchmarks and can accurately evaluate a tolerance range with the separated form error and profile error of workpiece. Additionally, an evaluation program based on the LS model is developed to extract the form error and the profile error of the elliptic section, which is well suited for separating the two errors by a standard program. Finally, the evaluation method about the form and profile errors of the ellipse is applied to the measurement of skirt line of the piston, and results indicate the effectiveness of the evaluation. This approach provides the new evaluation indicators for the measurement of form and profile errors of ellipse, which is found to have better accuracy and can thus be used to solve the difficult of the measurement and evaluation of the piston in industrial production.