Sewing System Needle Center Calibration via Image Processing
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Solution Overview
Problem
Existing sewing systems with robot arms face challenges in achieving precise needle center positioning, leading to suboptimal sewing quality due to inconsistencies between the set and actual needle center positions, which requires high-precision assembly and increases operational burden.
Innovation Solution
A sewing system equipped with a camera and a controller that captures images of stitch positions before and after rotating the sewing machine, allowing for calibration of the needle center position and acquisition of backlash data to accurately position the stitch, thereby reducing the operational burden and improving sewing quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sewing machine is precisely assembled to the robot arm to make the needle center position consistent, then the sewing quality is improved, but the burden of assembling work becomes very large
Solution Approach 1:
The system performs preliminary calibration actions by automatically capturing images of stitch positions and calculating the actual needle center position through image processing, eliminating the need for high-precision manual assembly while ensuring accurate needle center positioning
2Manufacturing precision
If the needle center position is precisely calibrated through manual assembly, then the sewing quality is improved, but the operational burden increases
Solution Approach 1:
The system performs self-calibration by automatically capturing images of stitch positions, processing the images to determine the actual needle center position, and updating the position data without requiring operator intervention, thereby improving accuracy while reducing operational burden
Solution Approach 2:
The system replaces manual mechanical calibration operations with an automated image-based calibration process, where the camera captures stitch positions and the controller calculates the needle center position through image processing, eliminating the need for manual measurement and adjustment
3Measurement precision
If image-based calibration is performed to recognize the actual needle center position, then the positioning accuracy is improved, but the system complexity increases
Solution Approach 1:
The camera serves multiple functions: it captures images for needle center calibration, acquires backlash data by capturing stitch positions before and after joint rotation, and can be used for general positioning tasks, thereby justifying the added system complexity through multiple useful applications
Data Source
AI summary
A sewing system comprises a sewing machine, a camera that captures an image of a reference position for sewing, a robot arm that holds the sewing machine and the camera, and a controller. The controller controls operations of forming a first stitch position that results from stitching of the sewing machine, and forming a second stitch position that results from stitching of the sewing machine after rotating the sewing machine at a prescribed angle about a rotation axis that passes through a needle center position stored by the controller. The controller further performs calibration processing that calibrates the needle center position stored by the controller, based on each position of the first stitch position and the second stitch position within image capture ranges of capture images that are obtained by capturing images of the first stitch position and the second stitch position using the camera.