Calibration-target-free universal hand-eye calibration method based on 3D vision

Abstract

The invention discloses a calibration-target-free universal hand-eye calibration method based on 3D vision. The calibration-target-free universal hand-eye calibration method based on 3D vision is common for the eye-to-hand condition and the eye-in-hand condition. The calibration-target-free universal hand-eye calibration method based on 3D vision comprises the steps that firstly, the center position of a flange plate of an end executor of a mechanical arm is kept constant, the end executor is controlled to only rotate, and a 3D vision sensor is utilized to collect coordinates of at least fourfeature points F for sphere center fitting; then, the posture of the end executor of the mechanical arm is kept constant, the end executor is controlled to only conduct horizontal movement, the coordinates of at least three feature points F are collected by a 3D camera, and a controller of a robot is used for recording or calculating the corresponding center position of the flange plate so as to estimate the rigid transformation parameter. The calibration-target-free universal hand-eye calibration method based on 3D vision has the beneficial effects that space information of the 3D vision sensor are fully utilized, a high error generated when the posture of the calibration target is measured is avoided, it is not needed to solve a complicated high-dimensional nonlinear matrix equation, andtherefore the calibration precision and calibration efficiency are high.

Description

technical field [0001] The invention relates to the field of industrial robots and automation, in particular, a general hand-eye calibration method based on 3D vision without a calibration board. Background technique [0002] In the automation system of the industrial manipulator, how to correctly obtain and understand the information about the operating space is a very critical issue. In most robotic arm systems, the best way to perceive the environment is to use visual data, because visual data can be obtained in a contactless and safe manner. The prerequisite for analysis in machine vision is hand-eye calibration. The so-called hand-eye calibration is to measure the relative posture and position relationship between the camera and the manipulator, which is a basic problem in manipulators. What the robotic arm system needs to analyze is a three-dimensional world, and 3D visual data can best be used to describe a 3D scene. In addition, the cost of 3D visual sensors has be...

AI Technical Summary

Problems solved by technology

This hand-eye calibration method has the following three disadvantages: first, the nonlinear optimization problem makes solving the above equations more complicated and time-consuming, and cannot achieve online calibration; second, the process of determining the attitude of the calibration board will introduce large errors, As a result, the accuracy of the final hand-eye calibration is not high; third, it is inconvenient or even impossible to use an accurate calibration plate in some occasions, for example, the mobile robot arm cannot carry the calibration plate due to its limited load

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