| In the context of the rapid development of industrial production automation,enterprise production is slowly developing from the initial manual to the direction of automation and informationization,and industrial robots are indispensable production machines in industrial automation.However,many robot manufacturers and researchers are troubled by the problem of low absolute positioning accuracy.In this paper,the IRB1200-5-0.9industrial robot is used as the research object,and two geometric parameter calibration methods are proposed to improve the absolute positioning accuracy through a low-cost and high-efficiency calibration method for the position errors at its end.This study is carried out in the following aspects:(1)The kinematic theory of industrial robots is investigated.Combining the geometrical structure parameters of the robot,the MD-H model is established.The kinematic equations of the industrial robot are introduced and the principles of solving forward and inverse kinematics are described.Finally,simulation experiments are conducted using MATLAB Robotics Toolbox to establish the MD-H model and complete the solution of forward and inverse kinematics to verify the correctness of the MD-H model.(2)Research on the end position accuracy detection method of industrial robots.Infrared vision detection system and laser range sensor detection system are proposed.The measurement methods of the two measurement systems are introduced in detail.For the infrared vision measurement system,the theoretical study of camera calibration and handeye-target calibration is conducted;For the laser distance sensor measurement system,the detection principle is introduced.Finally,pre-testing experiments are conducted for each of the two systems to lay the foundation and provide a method for the measurement of robot end position errors.(3)Research on the kinematic parameter identification and error compensation methods of industrial robots.Based on the error model of IRB1200 industrial robot,a calibration method combining least square method and N-R iterative algorithm is proposed,and the principles of the two algorithms are described respectively.Firstly,the least-squares method is used to identify the robot geometric parameters and obtain the corrected kinematic model,on the basis of which the N-R iterative algorithm is used to compensate the error in the joint space of the industrial robot and complete the calibration of the geometric parameters.(4)Set up an experimental platform for kinematic calibration experiments verification.Details the process of building the experimental platform of infrared vision measurement system and laser distance measurement sensor measurement system to complete the robot calibration experiments.By comparing the experimental results,it can be concluded that after the kinematic calibration of the robot by the infrared vision measurement system,the maximum value of the total spatial positioning error of the robot’s circular trajectory decreases from 0.9023 mm to 0.3986 mm,and the average value decreases from 0.6647 mm to 0.2927mm;The maximum value of the total positioning error of the linear trajectory decreases from 0.3650 mm to 0.1835 mm,and the average value decreases from 0.2546 mm to 0.0993 mm.After the kinematic calibration of the industrial robot by laser ranging sensor system,the maximum value of the total error of the robot’s spatial positioning decreases from 0.4212 mm to 0.2089 mm,and the average value decreases from 0.3331 mm to0.1791 mm.The experimental results verify that the two kinematic calibration systems proposed in this study can improve the absolute positioning accuracy of the robot,and both of them can be used in different robot calibration situations,which extends the idea of kinematic calibration. |
PDF Full Text Request