Robot Coordinate Calibration for Four-DOF Hand-Eye Alignment

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Solution Overview

Problem

Existing hand-eye calibration methods for six-degree-of-freedom robots are not applicable to four-degree-of-freedom robots, as they cannot determine the necessary rotation and translation matrices for accurate coordinate system calibration.

Innovation Solution

A method involving a calibration board parallel to a world coordinate plane, where a robot's execution component performs translation and rotary movements to collect coordinate information, allowing for automated determination of rotation and translation matrices without manual adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If hand-eye calibration methods for six-degree-of-freedom robots are used, then calibration can be performed for six-DOF robots, but these methods are not applicable to four-degree-of-freedom robots

Engineering Contradiction:

Improveapplicability of calibration methodVSAvoidcalibration accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the calibration approach parameters specifically for four-DOF robots by determining rotation matrices through translation movements and translation matrices through rotatory movements, adapting the calibration methodology to match the reduced degrees of freedom while maintaining calibration accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The calibration process is segmented into distinct phases: first determining the rotation matrix through translation movements, then determining the translation matrix through rotatory movements. This segmentation allows each matrix to be calculated using movements appropriate to the four-DOF robot's capabilities

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If automated calibration is implemented, then calibration convenience is improved, but calibration precision may be compromised without manual adjustment

Engineering Contradiction:

Improvecalibration convenienceVSAvoidcalibration precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs self-calibration by automatically controlling the execution component to perform translation and rotatory movements, and automatically calculating the rotation and translation matrices from collected coordinate information, eliminating the need for manual adjustment while maintaining precision through algorithmic computation

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The calibration process uses feedback from the photographic apparatus's coordinate information collection to automatically adjust and determine the transformation matrices, creating a closed-loop system that ensures calibration accuracy without manual intervention

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12528194B2Coordinate system calibration method, apparatus and system for robot, and medium

Publication Date: 2026.01.20 BEIJING JINGDONG QIANSHITECHNOLOGY CO LTD

AI summary

The present disclosure provides a coordinate system calibration method, apparatus and system for a robot, and a storage medium, wherein the method includes controlling an execution component of a robot to perform translation movement, and acquiring first coordinate information of the execution component, and second coordinate information which is collected by a photographic apparatus regarding a calibration board, so as to determine a rotation matrix; and controlling the execution component to perform rotatory movement, and acquiring third coordinate information which is collected by the photographic apparatus regarding the calibration board, so as to determine a translation matrix.