Error analysis of the articulated flexible arm CMM based on geometric method

Abstract

In order to overcome the disadvantage of traditional CMM (Coordinate Measuring Machine), a new type of CMM with rotational joints and flexible arms named articulated arm flexible CMM is developed, in which linear measurements are substituted by angular ones. Firstly a quasi-spherical coordinate system is put forward, the ideal mathematical model of articulated arm flexible CMM is established. On the base of full analysis on the factors affecting the measurement accuracy, ideal mathematical model is modified to error model according to structural parameters and geometric errors. A geometric method is proposed to verify feasibility of error model, and the results convincingly show its validity. Position errors caused by different type of error sources are analyzed, and a theoretic base for introducing error compensation and improving the accuracy of articulated arm flexible CMM is established.