| Along with the development of intelligent manufacturing and assembly of high-end era,the application of industrial robots has been never seen before development,in which the robot absolute positioning accuracy is the key performance parameter that decides whether a robot can be put into the automatic production line,but the robot positioning accuracy is not so high to be able to meet the rapid development of modern industry.Robot calibration technology can improve the accuracy of robot to achieve different job demands.Therefore,the absolute positioning accuracy and calibration technology of robots have become extremely important topics.In this paper,the influence factors of the absolute positioning accuracy of the industrial robot and the robot calibration technology are introduced in detail and the experimental research is carried out in detail.LR20 with six degrees of freedom industrial robot as the research object,according to the robot kinematics calibration method,first use the classic D-H model parameters based on robot differential error model is used to identify the parameters using the mapping relationship between D-H parameters and end position error,finally correction parameter are imported into the robot control system.The robot joint angle deviation are caused by the main pre calibration from robot mechanical zero,reduction ratio and verticality of three aspects,the research was conducted from the theoretical modeling,Simulink system simulation and experimental verification of the above content,The influence on pre calibration of robot absolute positioning accuracy is analized but also provides reliable the data of experiment for robot kinematics calibration.and reliable data of experiment for robot kinematics calibration are providedThis paper adopts Leica AT930 laser tracker as a measuring instrument to build an experimental platform for robot kinematic calibration,the calibration test system TCP position matrix and coordinate transformation model is deduced,the design parameter identification method is simple and unique,which verify the robot absolute average positioning accuracy of up to 0.5 mm.The robot kinematic calibration system of variable load weight relative error are caused by the robot position at the end of X,Y and Z in three directions,through further analysis of parameter identification of system structure parameters and load mapping relationship between the use of Matlab function fitting two,mapping relationship between system structure parameters and load is analyzed through further parameter identification and the development of a robot under variable load parameter error correction based on interface.In this paper,we use high-precision detection equipment to carry out robot position error optimization experiment and accuracy verification,and the result is in good agreement with the robot's terminal error calculated by the model.By calibrating the coupling factors,the position error of robot is reduced step by step.it also lays a foundation for the subsequent robot's automatic accuracy adjustment,and has certain practical value. |
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