Research On The Kinematics Calibration Method Of Industrial Robot

In the context of the continuous complexity and precision development of industrial robot application scenarios,the existing absolute positioning accuracy of robots has been difficult to meet the technological requirements of many industries in the production and processing.Robot calibration is the most useful measure to improve the absolute positioning accuracy of industrial robots.This paper focuses on the kinematics calibration method of industrial robots,taking the five-degree-of-freedom spray robot as the research object,and carries out research from kinematics modeling,error measurement,parameter identification and compensation,etc.,and finally improves the absolute positioning accuracy of the industrial robot.The main research contents are as follows:Firstly,the kinematics model of the 5-DOF robot is established according to the standard D-H method,the forward and inverse kinematics equations of the robot are derived,and the simulation is carried out in the robotic toolbox.The MDH model is introduced for the sudden change of the connecting rod offset at the parallel axis of the robot.The position error model is established by using the idea of differential motion,and the correctness of the model is verified by the simulation of preset geometric parameters.A method of robot end pose measurement based on infrared target measurement system is proposed,and the system is redeveloped.The accuracy of the integrated system is verified by experiments,and the accuracy can meet the requirements of robot calibration.A robot and the target’s pose solution method is based on the Rodrigue matrix to realize the conversion between the measurement coordinate system and the robot coordinate system.The influence of each joint kinematics parameter on the end position error is analyzed,and the redundant parameters are studied according to the singularity of the parameter matrix.Using singular value decomposition least square method to identify kinematic parameters,and the mathematical software is used to separately perform geometric parameter errors before and after eliminating redundant parameters to verify the correctness of the identification algorithm.Aiming at the problem that the encoder parameters of the robot may not be directly modified,a compensation method for the joint rotation angle is proposed based on the Newton iteration method.Design calibration experiment.The parameter identification interface is compiled based on the GUI function of mathematical software,and the transformation between robot coordinate system and measurement coordinate system is realized.The teaching points are selected in the workspace to calibrate the spraying robot,and the compensated robot precision is tested according to the position accuracy measurement method in the industrial robot performance specification.The experimental results show that the position accuracy of the spray robot calibrated by this method can be guaranteed within 0.65 mm.