Cold Rolling Feedforward Control for Camber and Sheet Breakage
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Solution Overview
Problem
Existing cold rolling methods struggle to maintain stability and prevent sheet breakage during the processing of difficult-to-roll materials with high loads and small sheet thickness, as they fail to accurately measure and control sudden fluctuations in unilateral elongation or camber, leading to poor shape quality and frequent sheet breakage.
Innovation Solution
A cold rolling method and equipment that utilize a shape measurement device to measure out-of-plane deformation, a calculation device to calculate leveling amounts, and a control device to adjust the rolling mill based on these measurements, incorporating machine-learned programs to predict and prevent excessive deformation, thereby stabilizing the rolling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If automatic feedback control is used to control leveling and bender, then shape control is improved, but sudden fluctuations in camber and shape defects cannot be coped with
Solution Approach 1:
The patent applies feedforward control based on shape measurement data from the upstream side to predict and compensate for camber and unilateral elongation before they affect the rolling process. This preliminary action allows the system to prepare control adjustments in advance, enabling response to sudden fluctuations without waiting for feedback from downstream measurements.
2Device complexity
If difference tension is used to predict unilateral elongation or camber, then control is simplified, but accurate prediction fails when change is rapid
Solution Approach 1:
The patent introduces shape measurement data as an intermediary parameter that directly reflects the actual shape state of the rolled material. This intermediary measurement provides more accurate information about camber and unilateral elongation than difference tension, enabling precise prediction and control even during rapid changes, while still maintaining a relatively simple control structure through feedforward compensation.
3Measurement precision
If cross-sectional shape measurement is used to calculate twist and C-warping height, then partial shape information is obtained, but accurate unilateral elongation or camber cannot be calculated
Solution Approach 1:
The patent measures shape data at multiple positions along the width direction of the rolled material to capture out-of-plane deformation characteristics. By adding this dimensional measurement capability, the system can directly obtain unilateral elongation and camber information that cannot be derived from cross-sectional measurements alone, thereby recovering the lost information while maintaining measurement precision.
4Force
If hot rolling thinning is applied to reduce rolling load, then rolling load is suppressed, but shape defects remain in the material
Solution Approach 1:
The patent converts the harmful shape defects remaining from hot rolling thinning into controllable parameters by measuring them upstream and using feedforward control to compensate for their effects during cold rolling. This approach transforms the previously problematic residual camber and unilateral elongation into information that can be used to adjust rolling conditions and achieve good final shape quality despite the high load thinning process.
Data Source
AI summary
A cold rolling method includes: a calculation step of calculating a leveling amount of a rolling mill using an out-of-plane deformation amount of a steel sheet measured on an upstream side of the rolling mill; a control step of controlling leveling of the rolling mill on a basis of the leveling amount calculated in the calculation step; and a cold rolling step of applying cold rolling to the steel sheet using the rolling mill controlled by the control step.