Mechanical arm DH parameter identification method based on least square method

Abstract

The invention discloses a mechanical arm DH parameter identification method based on a least square method. The method comprises the steps: determining the initial DH parameters of a mechanical arm according to the configuration and structural parameters of the mechanical arm, and constructing a mechanical arm error model according to a differential motion principle; based on the initial DH parameters of the mechanical arm, conducting self-calibration on the mechanical arm through a calibration plate, and recording encoder values of all joints, corresponding to all sets of points, of the mechanical arm; parameterizing the mechanical arm error model through the least square method in combination with the encoder values; according to the parameters of the mechanical arm error model and the initial DH parameters of the mechanical arm, obtaining the tail end position of each set of points, and calculating the difference value between each tail end position and the absolute position of a fixed point; and identifying the parameters of the mechanical arm error model by comparing the difference values with a set threshold value. According to the method, parameter identification is carried out by constructing the error model and through self-calibration of the calibration plate, the absolute positioning precision of the mechanical arm is effectively improved, and the cost can be reduced.

Description

technical field [0001] The invention relates to the technical field of robots, in particular to a method for identifying DH parameters of a manipulator based on the least square method. Background technique [0002] Robot accuracy mainly includes repeat positioning accuracy and absolute positioning accuracy. It is one of the important indicators to evaluate the comprehensive performance of robots. There are two main methods to improve absolute positioning accuracy: error prevention method and parameter calibration method. The error prevention method mainly ensures the positioning accuracy of the robot by improving the machining accuracy (assembly accuracy and control system accuracy). It is rarely used in practice; the parameter calibration method mainly uses advanced measurement technology to identify the actual kinematic parameters of the robot, and corrects the parameters in the controller or adds some control algorithms to improve the absolute positioning accuracy. [0...

AI Technical Summary

Problems solved by technology

[0003] Because the parameter calibration method is simple to operate, easy to implement, and can compensate positioning errors online, it has attracted extensive attention from domestic and foreign researchers, and has achieved a series of research results in the factors affecting absolute positioning accuracy errors, calibration measurement, and absolute positioning accuracy error compensation. results, but the absolute positioning accuracy is still not ideal

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