精密用機械手機構參數的評估與運動軌跡動態特性的研究

Abstract

機械臂由於加工、安裝及變形等種種因素將導致其機械參數的實際值與設計值的偏 差，連帶地影響了手端的定位精度。本研究的重點是針對精密定位的四個自由度之機器 手臂的設計製作為參考目標，對設計有關的誤差補償，參數敏感度分析，可操縱性分析 等方面進行研究、探討，並建立簡便實用的分析工具與程式。利用已知機構參數求出機 械臂各機構參數對定位點位置的敏感度，做為機械臂加工與組裝時誤差補償時的參考因 數，由可操控性指數的計算以判斷機械臂的靈活程度。最後採用3D雷射軌跡追蹤儀去量 測機械臂手端在空間座標的定位偏差量，並利用運動學的理論導出機械臂各機構參數的 誤差與手端定位精度的關連模式。再將此參數補償回饋機械手臂之控制系統，以改善機 械臂手端於空間定位中的精確性，同時也由路徑追蹤的軌跡座標中，分析歸納實際機械 手在精密定位工作任務中適用的工作軌跡，做為機械手臂操控與軌跡歸劃時的參考。

Because of the difference between of the design values and the real values resulting from manufacturing, installation and deflection of the robot arm, the influence to the positioning accuracy becomes more important. The focal point of this research is to aim directly at the design procedure of the robot with four degree freedom to error compensation, parameter sensitive analysis and manipulability for positioning accuracy, so as to establish an easy way to practical analysis and programming. The keen factor to the error compensation during manufacturing and assembly of the robot arm is made up from sensitivity of positioning accuracy to the kinematical parameters of the robot arm so as to lay out the robot arm sensitivity from the manipulability index. And then we can measure the different position of the robot arm in space coordinate by means of 3D laser tracker in order to set up a correlated model between the error to each kinematics parameters and the accuracy to the robot arm based on kinematics theory. The parameter compensation feeds back to the control system of the robot so that we can improve the positioning accuracy of the robot arm in space and we can figure out a reference to control and project a robot arm for suitable trajectory in a more accurate position at work by tracing the locus coordinate at the same time.