Tandem Rolling Thickness Scheduling Under Stand Parameter Limits
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Solution Overview
Problem
Conventional plate thickness schedule calculation methods for tandem rolling mills face stagnation issues when a large number of rolling stands or significant correction amounts are involved, leading to high calculation loads and difficulty in converging repeated calculations.
Innovation Solution
A method that selects between two derived functions based on parameter restrictions in rolling stands, using a matrix to modify delivery side plate thickness, and employs a process computer to calculate the plate thickness schedule, ensuring appropriate correction and preventing calculation stagnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plate thickness schedule correction method is used, then calculation can converge when small number of rolling stands require correction, but calculation becomes stagnant when large number of stands require correction
Solution Approach 1:
The patent dynamically switches between two different correction approaches based on the correction amount: when correction amount is small, it uses the conventional force ratio adjustment method; when correction amount is large, it switches to a direct thickness correction method. This dynamic adaptation prevents calculation stagnation while maintaining convergence reliability.
Solution Approach 2:
The patent changes the correction parameter strategy based on the magnitude of required correction. For small corrections, it adjusts force ratios gradually; for large corrections, it directly modifies thickness parameters. This parameter change approach allows the system to handle both small and large correction scenarios effectively without stagnation.
2Manufacturing precision
If conventional correction method reduces force ratio target value, then plate thickness can be corrected, but calculation load increases and convergence becomes difficult when correction amount is large
Solution Approach 1:
The patent segments the correction process into two distinct methods: one for small corrections (force ratio adjustment) and one for large corrections (direct thickness correction). This segmentation allows each method to be optimized for its specific range, reducing overall calculation complexity while maintaining precision.
Solution Approach 2:
The patent applies partial correction action by selecting the appropriate correction magnitude based on the situation. For small deviations, it uses gentle force ratio adjustments; for large deviations, it applies more direct thickness corrections. This partial action principle prevents excessive calculation iterations while achieving the required precision.
Data Source
AI summary
A plate thickness schedule calculation method includes a plurality of steps. One step acquires a rolling model expression including a roll force model or a motor power model. Another step determines whether or not a parameter restriction has occurred that restricts at least one parameter of roll force, motor power and a reduction rate in each rolling stand. Further another step is to select a first derived function when no parameter restriction occurs and to select a second derived function when the parameter restriction has occurred in accordance with a result of the determination for each rolling stand. Still another step modifies each delivery side plate thickness in each rolling stand using a matrix including the one derived function selected from the first derived function and the second derived function in accordance with the result of the determination.