Rolling Strip Flatness Detection Using Local Frequency Analysis
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Solution Overview
Problem
Existing methods for rolling metal materials face challenges in accurately identifying and correcting flatness errors, especially under harsh environmental conditions such as high temperatures, vibrations, and contamination, which can impede the operation of measuring devices and require high space requirements.
Innovation Solution
An operating method that uses a camera-based acquisition device to iteratively acquire two-dimensional data sets of the metal surface, determining error values based on intensities and spatial frequencies of local oscillations through Fourier transforms, and supplies these values to a control device for real-time feedback control, allowing for precise flatness correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contactless acquisition devices are used to measure flatness under harsh environmental conditions (high temperatures, vibrations, contamination), then measurement reliability is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent replaces mechanical contact-based measurement systems with optical acquisition devices that work contactlessly. The camera-based system captures images of the rolling material surface without physical contact, eliminating the problems of high temperatures, vibrations, and contamination that affect mechanical sensors. This substitution maintains measurement reliability while reducing device complexity and space requirements.
Solution Approach 2:
The patent creates a digital copy (image) of the rolling material surface instead of using physical sensors that must touch the material. The camera captures optical information and converts it into image data that can be processed digitally to determine flatness errors. This copying approach eliminates the need for complex mechanical measurement systems while maintaining accurate flatness detection.
2Manufacturing precision
If iterative repeated acquisition of two-dimensional data sets is performed to accurately identify flatness errors, then manufacturing precision is improved, but productivity decreases due to increased measurement time
Solution Approach 1:
The patent implements periodic iterative acquisition of two-dimensional data sets at fixed time intervals along the transport direction. Multiple images are captured at different positions and iteratively processed to identify flatness errors with high accuracy. This periodic sampling approach ensures comprehensive coverage of the rolling material surface while maintaining a systematic measurement process that balances precision with production speed.
Solution Approach 2:
The patent performs preliminary processing of acquired images by dividing them into strips and selecting representative images before final evaluation. This preliminary action reduces the computational burden of processing all acquired images in detail, allowing iterative repeated acquisition to maintain high manufacturing precision while reducing the time required for complete analysis, thus preserving productivity.
3Measurement precision
If comprehensive two-dimensional data sets are acquired over the entire width of the rolling material, then measurement precision is improved, but the space requirements and data processing complexity increase
Solution Approach 1:
The patent divides the rolling material width into multiple strips and processes each strip separately. By segmenting the wide two-dimensional data set into narrower strips, the system achieves comprehensive flatness measurement across the entire width while reducing the computational complexity and memory requirements compared to processing the complete wide image as a single unit. This segmentation allows accurate flatness identification without requiring excessive processing space.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables simple, reliable, and efficient identification and correction of flatness errors, improving the flatness and reducing internal stress in rolled metal materials while being robust and space-efficient.
Implementation Method 1
at least one two-dimensional data set of the surface of the planar rolling material is iteratively repeatedly acquired on the output side of the roll stand by means of an acquisition device which works contactlessly
Implementation Method 2
determining error values based on intensities and spatial frequencies of local oscillations through Fourier transforms
Data Source
AI summary
An evaluation device that determines, based on data acquired by an acquisition device, an error value (PF) relating to the flatness of a strip of a rolling material exiting a roll stand, and supplies the determined error values (PF) to a control device, which takes the error values (PF) into account when determining adjustment variables(S) for flatness control elements of the roll stand. The interaction of the acquisition device, the evaluation device, the control device and the roll stand results in a closed control loop working in real time. In order to determine the particular error value (PF) of the strip, the evaluation device performs a local frequency analysis of the data and determines the particular error value (PF) on the basis of the local frequency analysis.