Rolling Mill Gap Measurement Using External Camera Calibration
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Solution Overview
Problem
Existing methods for determining rolling or guiding gaps in multi-stand rolling mills are complex, particularly for central roll stands, and suffer from significant imaging inaccuracies due to the length of the rolling mills and the need for physical components and reference sensors.
Innovation Solution
A method involving a camera and background illumination arranged on opposite sides of the rolling mill, with offline or inline calibration using an information technology device, allows for precise determination of rolling or guiding gaps without physical intervention in the rolling mill, minimizing effort and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If template bodies are clamped between rolls and aligned by laser system, then measurement precision is improved, but device complexity and ease of operation deteriorate due to complex clamping and alignment procedures
Solution Approach 1:
The patent extracts the measurement function from the rolling mill interior by positioning the camera and illumination outside the rolling mill. The camera is arranged at one side and the illumination at the other side, allowing measurement without physical intervention inside the rolling mill. This eliminates the need for template bodies and laser alignment systems while maintaining measurement precision through the external optical arrangement.
Solution Approach 2:
The patent introduces an intermediary optical path through the rolling mill structure. Instead of direct measurement inside the rolling mill, the camera and illumination system create an indirect measurement path that passes through the rolling mill exterior. This intermediary approach allows precise measurement without requiring physical access to the interior roll stands.
2Ease of operation
If camera and illumination are arranged on one side with reflector on the other side, then ease of operation is improved, but measurement precision deteriorates due to significant imaging inaccuracies from long rolling mill lengths
Solution Approach 1:
The patent creates an optical copy of the gap region by using the camera to capture images of the gap area. The illumination system provides lighting that allows the camera to form an accurate optical copy of the gap geometry. This copying approach maintains measurement precision by capturing the actual gap dimensions through the optical path, avoiding the inaccuracies of indirect reflection methods.
3Measurement precision
If reference sensors are introduced into the rolling mill for each measurement, then measurement precision is improved, but productivity deteriorates due to time-consuming installation and removal
Solution Approach 1:
The patent performs preliminary positioning of the camera and illumination system outside the rolling mill before measurements are needed. The optical path is pre-configured to pass through the rolling mill structure, allowing immediate measurements without introducing reference sensors during operation. This preliminary setup maintains measurement precision while eliminating the time-consuming installation and removal of reference sensors.
Solution Approach 2:
The patent makes the rolling mill structure itself serve as the reference frame for measurements. By using the existing rolling mill geometry and structure as the measurement baseline, the system eliminates the need for separate reference sensors. The rolling mill's own structure provides the reference, allowing rapid measurements without external sensor installation while maintaining precision through the self-referential measurement approach.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables determination of rolling or guiding gaps with high precision and minimal effort, reducing downtime and maintaining operational efficiency by allowing calibration and measurement from both sides of the rolling mill.
Implementation Method 1
a camera is arranged at one of the input or output sides... the camera determines the rolling or guiding gaps inline
Implementation Method 2
a background illumination is arranged correspondingly on the other one of the input or output sides
Data Source
AI summary
In order to be able to determine the rolling or guiding gaps of the roll stands or guide stands in a multi-stand rolling mill, at a predetermined measurement precision, with the least possible effort, a master calibration and intermediate calibrations are carried out, wherein various calibration measures are refrained from, in a targeted manner. The targeted lack of recourse in the case of specific calibrations is also independently advantageous.