Tandem Rolling Mill Control System for Strip Thickness Accuracy
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Solution Overview
Problem
Existing tandem rolling mill control systems face challenges in accurately determining roll positions without special detectors, leading to inconsistencies in strip thickness and increased costs due to the need for inter-stand thickness gauges, which are not always available in hot strip rolling.
Innovation Solution
A control system that predicts roll force and position using target strip thickness, chemical composition, and rolling results, with sections for calculating roll position deviations and compensation amounts, allowing for accurate roll position adjustments without special detectors, thereby enhancing strip thickness accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an inter-stand thickness gauge is provided to correct roll position, then strip thickness accuracy is improved, but system cost and maintenance complexity increase
Solution Approach 1:
The patent replaces the mechanical inter-stand thickness gauge with a computational model that calculates strip thickness based on roll position, roll force, and material properties. The thickness calculation section computes predicted thickness using rolling theory equations, eliminating the need for physical thickness measurement devices between stands.
Solution Approach 2:
The system uses existing sensors and process data (roll position, roll force, material composition) to self-determine strip thickness without external measurement equipment. The control system leverages its own operational parameters and built-in computational capabilities to achieve thickness control.
2Manufacturing precision
If strip thickness charts are memorized and classified by steel grades, then head end thickness control is improved, but calculation amount and processing complexity increase
Solution Approach 1:
The patent transitions from storing complex thickness charts to using fundamental material parameters (chemical composition, density) and rolling parameters (roll force, roll position) in computational models. This parameter-based approach simplifies data storage while maintaining predictive accuracy through physics-based calculations.
Solution Approach 2:
The patent replaces the empirical chart-based system with a theoretical model based on rolling mechanics and material science. The thickness prediction is derived from first principles equations involving roll force, roll position, and material properties, eliminating the need for extensive data collation and chart memorization.
3Stability of the object's composition
If roll position is determined by prediction calculation, then rolling stabilization is improved, but accuracy of target thickness attainment deteriorates due to unmodeled variations
Solution Approach 1:
The patent implements feedback by comparing predicted strip thickness with actual thickness measurements from the delivery side. The thickness deviation is calculated and used to generate compensation amounts that adjust roll position predictions for subsequent strips, continuously improving accuracy while maintaining rolling stability.
Solution Approach 2:
The system performs preliminary roll position adjustment based on predicted thickness deviations before actual rolling occurs. Compensation amounts are calculated in advance for the next strip based on previous rolling results, allowing proactive correction of systematic errors while the mill operates stably.
Data Source
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AI summary
In addition to a control reference setup means calculating control reference for a roll position, an inter-stand strip thickness calculation means 111 predicting a strip thickness between stands 161, a roll position deviation calculation means predicting a roll position with using rolling results captured from a controlled object and calculating a deviation between the predicted roll position and an actual roll position, a strip thickness deviation calculation means 113 calculating a deviation between a target strip thickness, at a finish mill delivery side that is fetched from the control reference setup means, and an actual strip thickness obtained as a rolling result, and a roll position compensation amount calculation means 115 calculating a roll position compensation amount from a roll position deviation and a strip thickness deviation are provided, and the control reference setup means is configured to calculate the roll position using the calculated roll position compensation amount.