Rolling Mill Control Switching for Stable AGC Across Speed Thresholds
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Solution Overview
Problem
Conventional rolling control systems face difficulties in continuing automatic gauge control (AGC) after switching from automatic tension regulator control (ATR) as the rolling speed increases, leading to potential conflicts with upper restrictions and tension fluctuations.
Innovation Solution
A rolling control system with a controller that selects between speed and tension control and roll gap and plate thickness control based on rolling speed, setting speed correction amounts to zero and calculating roll gap correction amounts to prevent conflicts and fluctuations, ensuring smooth transition and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the control method is switched from ATR to AGC as rolling speed increases, then the plate thickness control accuracy is improved, but the speed correction amount from before switching may conflict with upper restrictions and prevent continuous AGC operation
Solution Approach 1:
The patent applies preliminary action by resetting the speed correction amount to zero at the moment of control method switching. This prevents the carryover of speed correction amounts from ATR mode that could conflict with upper restrictions in AGC mode, ensuring smooth transition and continuous operation without exceeding speed limits
Solution Approach 2:
The patent changes the parameter state of the speed correction amount by resetting it to zero during mode switching. This parameter change eliminates the conflict between pre-switching speed corrections and post-switching speed restrictions, allowing reliable continuous AGC operation while maintaining high plate thickness control accuracy
2Stability of the object's composition
If the entry-side tension deviation is adjusted during switching, then the tension stability is improved, but the adjusted deviation may still lead to excessive AGC control amounts that conflict with restrictions
Solution Approach 1:
The patent extracts the problematic speed correction amount from the control calculation by resetting it to zero during switching. This separates the tension stabilization function (handled by entry-side tension deviation adjustment) from the speed correction function, preventing the combination from producing excessive control amounts that would conflict with system restrictions
Data Source
AI summary
A rolling controller executes speed and tension control, and roll gap and plate thickness control when rolling speed is less than a boundary value, while executing roll gap and plate tension control, and speed and plate thickness control when the rolling speed is equal to or greater than the boundary value. If the rolling speed rises across the boundary value, the rolling controller sets the rolling speed to zero such that a speed correction amount in the speed and tension control before the transboundary is not reflected to a calculation executed in the speed control amount of the rolling speed after the transboundary.