Precision Positioning Technology For End Of Industrial Robot

To solve the problem of low positioning accuracy of manual marking in aircraft assembly process,this paper builds a structural component assembly system based on industrial robot.In order to ensure the accuracy of aircraft structures positioning to meet the requirement,the influence factors of structure positioning accuracy are analyzed,therefore the influence factors are divided into two categories: the absolute positioning accuracy of robot and the accuracy of coordinate system.In order to improve the robot absolute positioning accuracy,two kinds of plan for title paving are proposed:(1)Plan based on robot kinematics parameters calibration(2)Plan based on on-line positioning compensation of robot.Based on the above analysis,the main content of this paper is decided as:(1)Establishment of coordinate systems and precision analysis of systems: First,the coordinate systems are established and unified.Then,the accuracy of the robot root coordinate system and the structure coordinate system are analyzed.As a result,the robot's root coordinate system and the structure coordinate system are calibrated.(2)Plan based on robot kinematics parameters calibration: The D-H model of KUKA robot is established first.Then by calculating the kinematics error model of robot,the average position error of the structure is reduced from 1.587 mm to 0.614 mm,increased by 61.3%.The average attitude error decreases from 0.084o to structure 0.032o,increased by 61.9%.(3)Plan based on on-line positioning compensation of robot: The positioning precision of the robot is improved by the error iterative compensation and the online error feedback.Thereby,the average position error of structure is reduced from 1.642 mm to 0.021 mm,increased by 98.7%.The average attitude error decreases from 0.084o to 0.008o,increased by 90.5%.