Statistical Localization Variance Analysis for Localization Accuracy Consideration in 2D Precision Fixture System

摘要

This paper presents Root Sum of Square (RSS) statistical localization variance analysis and Monte Carlo simulation method for the characteristics of localization variance and localization accuracy of 2D precision fixture system. Prismatic workpiece with line or arc fixturing contact edges is located by three locators in deterministic localization of unique and accuracy position and orientation. The deterministic localization analysis is employed to verify the necessary fixturing condition of 3-points contact. According to the localization variances of fixturing contact points and the shapes of prismatic workpiece, the translational and rotational variance of a workpiece can be expressed by the normal and tangent localization variances of fixturing contact points by using RSS statistical localization variance analysis. Monte Carlo simulation is carried out to verified validation. The normal localization variances of fixturing contact points are more important than the tangent ones for the translational and rotational variance of a workpiece. The relative fixturing position of locators with minimum localization variance is the relative fixturing position of locators with the best localization accuracy. The results of two analyses are consistent with each other.