Coating Weight Control Near Welding Points
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Solution Overview
Problem
In steel coating plants, the accuracy of coating weight control is compromised due to irregular strip shapes near welding points, leading to nozzle misalignment and degraded prediction models, resulting in inaccurate nozzle pressure calculations and reduced coating weight control precision.
Innovation Solution
A coating weight control apparatus that includes a preset control unit, tracking unit, stable value storage, feedback control unit, and switching unit to dynamically adjust nozzle pressure based on current strip speed, nozzle gap, and target coating weight, using a combination of absolute and relative preset values to maintain accurate control, especially near welding points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nozzle opening and closing control is performed near welding points, then nozzle contact with strip is avoided, but prediction accuracy of coating weight model is degraded
Solution Approach 1:
The system performs preliminary determination of welding point passage timing based on strip speed and nozzle position, and preemptively switches from relative preset calculation to absolute preset calculation before the welding point passes through the nozzle position. This prevents the model degradation that would occur if relative calculation were performed during nozzle opening/closing transitions.
Solution Approach 2:
The invention changes the calculation method parameter from relative preset (based on previous values) to absolute preset (based on current strip speed, nozzle gap, and target coating weight) when welding point passage is detected. This parameter switching ensures accurate coating weight prediction even when nozzle position changes dramatically near welding points.
2Speed
If relative preset calculation is used for nozzle pressure control, then control responsiveness is improved, but accuracy is degraded when nozzle pressure reaches saturated pressure
Solution Approach 1:
The system continuously monitors nozzle pressure to detect saturated pressure conditions, and uses this feedback information to switch from relative preset calculation to absolute preset calculation. The absolute calculation method recalculate nozzle pressure from first principles (strip speed, nozzle gap, target coating weight) rather than relying on previous values, thereby maintaining accuracy even when pressure saturation occurs.
3Measurement precision
If absolute preset calculation is used for coating weight control, then prediction accuracy is maintained, but calculation complexity increases
Solution Approach 1:
The invention implements a dynamic control system that automatically switches between relative preset and absolute preset calculation methods based on operating conditions (welding point passage detection, pressure saturation). This dynamic adaptation maintains high prediction accuracy when needed while using the simpler relative method during normal stable operation, thereby balancing accuracy requirements with system complexity.
Data Source
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AI summary
[Task] There is a problem in that a nozzle pressure control is performed with high accuracy in a coating weight control requiring nozzle opening and closing near a welding point 411. [Solving means] A tracking unit 102 which determines whether or not it is the stable condition, by determining whether or not a coating weight acquired from a steel coating plant 2 is a coating weight based on a current nozzle pressure, a nozzle gap, and a strip speed, based on positional information of a strip 401 based on a movement distance of the strip 401, a preset control unit 101 which calculates a preset value for controlling the nozzle 211 based on a stable coating weight, a stable strip speed, and a stable nozzle gap at a timing of determining whether or not it is the stable condition, and an addition output unit 106 which outputs a control signal of the nozzle 211 based on the preset value, are included.