Conveyor Coordinate Alignment Using Camera-Based Index Tracking
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Solution Overview
Problem
Existing methods for setting a transport device coordinate system in a robot coordinate system are cumbersome and require physical contact or visual calibration, which can be inefficient and inaccurate.
Innovation Solution
A method and device using a first index placed on a transport device, imaged by a camera to acquire position data, determining the transport direction, and setting the transport device coordinate system in the robot coordinate system based on these data without physical contact or visual calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If physical contact method (touching up robot front end to transport device) is used for calibration, then the calibration can be performed with simple equipment, but the process is cumbersome and time-consuming
Solution Approach 1:
The patent replaces the mechanical contact-based calibration method with an optical imaging system. A camera captures images of an index plate attached to the transport device, and a control unit calculates coordinate system relationships through image processing and geometric computations, eliminating the need for physical contact between the robot and transport device.
Solution Approach 2:
The patent creates a visual copy of the transport device's coordinate system through camera imaging. By capturing images of the index plate with known geometric features and processing these images to extract position and orientation data, the system establishes the transport device coordinate system without physical interaction.
2Ease of operation
If visual calibration method (camera imaging multiple marks) is used, then calibration can be performed without physical contact, but the process requires complex visual calibration procedures
Solution Approach 1:
The calibration process is divided into distinct sequential steps: attaching the index plate to the transport device, capturing images at multiple predetermined positions, extracting coordinate information from each image, and computing the final coordinate system relationship. This segmentation makes the complex calibration process more manageable and systematic.
Solution Approach 2:
The index plate with known geometric features is pre-attached to the transport device before calibration begins. The robot is programmed with predetermined positions for image capture in advance. These preliminary preparations simplify the actual calibration execution by eliminating the need for real-time complex positioning and marking procedures.
3Measurement precision
If multiple image captures at predetermined positions are performed, then accurate coordinate system setting is achieved, but the calibration process requires multiple steps and positions
Solution Approach 1:
The index plate serves as an intermediary object between the robot and the transport device. It contains known geometric features (such as circular patterns or fiducial markers) that the camera can easily detect and measure. By measuring the index plate at multiple positions, the system accurately determines the transport device's coordinate system without directly measuring the transport device itself.
Solution Approach 2:
The calibration process utilizes changes in the index plate's apparent position and orientation parameters as captured in successive images. By analyzing how these parameters change across multiple predetermined positions, the system computes the three-dimensional coordinate system relationship through geometric calculations and optimization.
Data Source
AI summary
A device includes: a first indicator; a camera that acquires first image data in which the first indicator is imaged and second image data in which the first indicator conveyed after the imaging by a conveyance device is imaged; a position data acquiring unit that acquires first position data that indicates a three-dimensional position with respect to the camera in a first indicator coordinate system expressed by the first indictor captured in the first image data, and second position data that indicates a three-dimensional position with respect to the camera in a first indicator coordinate system expressed by the first indictor captured in the second image data; a conveyance direction acquiring unit that derives the conveyance direction; and a coordinate system setting unit that sets the conveyance device coordinate system to the robot coordinate system on the basis of the conveyance direction.