機械手臂之關節間隙評估與運行精度提升之方法

Abstract

本論文以設計、分析的方法探討機器手臂的準度提昇方案，提出一套由機 械手臂運行軌跡推估關節間隙的方法。透過建立機械手臂結合關節間隙之動態模型，並探討關節間隙所導致的軌跡誤差，建立關節間隙與軌跡誤差間的關係式。當給定機械手臂軌跡誤差後藉由此關係式可推估出關節間隙之大小，再經由最佳化流程規劃出誤差較小之路徑，提升機械手臂之準度。本研究之方法可評估重複精度相同但間隙不同的機械手臂位於工作空間中的性能，並將一存在三個關節間隙（其值為0.328 mm、0.171 mm、0.483 mm）之機械手臂位於目標點的平均誤差由0.637 mm 降低至0.031 mm，準度改善了95.1%，結果顯示本研究方法能比較機械手臂間的性能，並有效提高機械手臂之準度。

This study presents a method to improve manipulator accuracy by predicting uncertainty from the trajectory of manipulators. We construct the dynamic of manipulators with clearances equations and use them to obtain the operation error of a given trajectory. We are able to predict the joint clearance and arrange a trajectory with smaller error through optimization technics using the proposed method. This study reduces the average error at target points from 0.637 mm to 0.031 mm for robot manipulator with joint clearance 0.328 mm, 0.171 mm, and 0.483 mm, that is a 95.1% improvement in accuracy over the same manipulator before optimization. Our method can not only compare the true manufacturing quality of two robot manipulators, but also provide a more accurate operation.