Rolling Mill Stand Control for Strip Edge Wave Prevention
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Solution Overview
Problem
Current methods for controlling the rolling of metal strips in roll stands fail to effectively prevent waves in the rolled metal, which can disrupt the rolling process and lead to operational issues like strip doubling and high-speed problems, due to the influence of both measurable and non-measurable variables.
Innovation Solution
A control method that determines whether waves are forming at the strip edges by analyzing image data from cameras, adjusting the roll stand parameters to counteract or limit wave formation, and storing these parameters for future rolls with similar characteristics to prevent wave occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lateral position of the metal strip is adjusted by pivoting the rolls to track the target position, then the lateral position control is improved, but waves may form in the rolled metal strip causing disruptions
Solution Approach 1:
The control device determines variables indicating wave formation at strip edges and uses this feedback to dynamically adjust roll stand parameters. The system continuously monitors the rolling process and modifies pivot values based on detected wave conditions, creating a closed-loop control system that prevents waves while maintaining lateral position accuracy.
Solution Approach 2:
The system changes operational parameters of the roll stand, specifically adjusting the pivot value limits based on detected wave formation. When waves are detected, the control device modifies the maximum and minimum pivot values to counteract the wave formation, thereby resolving the contradiction between maintaining lateral position and preventing waves.
2Reliability
If the roll stand parameters are adjusted to prevent wave formation, then the reliability of the rolling process is improved, but the complexity of the control system increases
Solution Approach 1:
The control device automatically detects wave formation and adjusts roll stand parameters without external intervention. The system monitors its own operation through image analysis of the strip and self-corrects by modifying pivot values, eliminating the need for additional complex control mechanisms while maintaining reliability.
Solution Approach 2:
The system replaces complex mechanical adjustment mechanisms with an automated control algorithm that processes image data and calculates appropriate parameter adjustments. This substitution of mechanical complexity with computational logic simplifies the overall system while achieving wave prevention.
3Manufacturing precision
If image data is analyzed in real-time to detect wave formation, then the manufacturing precision is improved, but the processing time and complexity increase
Solution Approach 1:
The control device focuses image analysis specifically on detecting wave formation at strip edges rather than analyzing the entire strip. By concentrating computational resources on the critical detection of waves rather than comprehensive strip analysis, the system achieves high detection accuracy while minimizing processing time.
Data Source
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Figure 3
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AI summary
A control device (3b) for a rolling mill stand (1) receives measurement data for the lateral position of the metal strip (2) at the entry and/or exit side of the rolling mill stand (1) during the rolling of a metal strip (2) in the rolling mill stand (1). A stand controller (3a) of the control device (3b) determines a pivot value for the rolling mill stand (1) based on parameters (P) of the stand controller (3a) and the deviation of the lateral position from a target position, and controls the rolling mill stand (1) accordingly. The control device (3b) determines at least one parameter that indicates, for both edges of the metal strip (2), whether the metal strip (2) forms a wave in the region of the respective edge.As soon as the metal strip (2) forms a wave in the area of one of the strip edges, the control device (3b) varies at least one of the parameters (P) of the frame controller (3a), so that the frame controller (3a) determines the swivel value from the variation of the at least one parameter taking into account the changed parameter.