Positional Accuracy Analysis of the Polishing Robot Based on Product-of-exponential Formulas

Abstract

In order to establish the relationship between error sources and the position errors of the polishing robot end-effector, this work has developed a kinematics model with geometric errors of the polishing robot based on product-of-exponential (POE) formulas. The error spinors can be obtained by determining the geometric relationship of error sources, which result in poor positional accuracy of the robot end-effector. The process of positional accuracy analysis was fully carried out by introducing error spinors into the kinematics model to resolve the two problems. According to the geometric tolerances, error spinors were established describing the geometric errors as one of the components in the actual kinematics model. Then, a significant impact on the end-effector position error is provided by the further positional accuracy analysis process to make a precision reference for the proposed optimization program. The results show that the structural errors and transmission errors are the main factors in the robot static positional accuracy, where the structural errors are systematic errors that can be reduced or compensated for by the precision design, and transmission errors can be resolved by the latter calibrate program.