Research On Error Modeling And Accuracy Calibration Method Of Serial Robot

In order to improve the absolute positioning accuracy of the end-effector of the industrial robot under load,the modeling,identification,compensation of geometric error and calibration method of load deformation error are studied in this paper.The specific work is as follows:(1)The geometric error modeling method of serial robot.Based on the finiteinstantaneous screw(FIS)theory,a geometric error modeling method for serial robot is proposed.The mapping relationship between the joint axis error and the end pose error is analyzed in the case of single rotating joint and single moving joint,and the general error model of the n Do F serial robot in general is established.On this basis,a complete,continuous and non redundant error model of UR3 series robot is established,which shows the generation,accumulation and transmission process of geometric error of series robot;(2)The geometric error identification and compensation methods of serial robots.Based on the original error model,the complete error model(CEM)and the minimum error model(MEM)are constructed.The least square algorithm and hybrid genetic algorithm are used to identify the parameters of the two error models,and the accuracy of parameter identification in different cases is compared.A geometric error compensation method is proposed,which is used when the bottom control program of serial robot is not open.For UR3 series robot,the simulation and experimental are carried out to verify the correctness of the above method;(3)The load error calibration method of serial robot.The joint stiffness identification model of serial robot is constructed,and a supplementary stiffness matrix is proposed to improve the joint stiffness identification accuracy.On this basis,a simple and effective joint stiffness identification model of UR3 series robot is constructed and verified by experiments;In response to the practical processing application requirements of high precision and heavy load of serial robot,the positioning error of robot is caused by geometric error and load deformation error.In order to improve the positioning accuracy of robot,the geometric error calibration and load deformation error calibration are carried out respectively,and the UR3 series robot is taken as an example for experimental verification.