Rotational Body Misalignment Calculation via Error Minimization
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Solution Overview
Problem
Conventional methods for calculating misalignment in rotational bodies, such as gas turbine rotors, require extensive calculations and are prone to inaccuracies due to the inclusion of abnormal measurement values, making them complex and unreliable.
Innovation Solution
A method involving the selection of at least four measurement points to calculate radial displacement amounts, determining a 'most probable circle' by minimizing error values between calculated and measured displacement amounts, and identifying and replacing abnormal values to ensure accurate misalignment data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to calculate misalignment, then calculation is performed using all measurement points, but calculation complexity increases and accuracy decreases due to inclusion of abnormal values
Solution Approach 1:
The patent extracts and removes abnormal measurement values from the calculation process. By identifying measurement points where the difference between measured and calculated displacement amounts exceeds a threshold, these abnormal values are excluded from the misalignment calculation, thereby improving accuracy without significantly increasing complexity
Solution Approach 2:
The patent segments the measurement points into normal and abnormal categories based on error analysis. By dividing the measurement data and selectively using only normal measurement points for calculation, the method achieves more accurate results while keeping the calculation process manageable
2Reliability
If all measurement points are used in calculation, then more data is utilized, but abnormal values reduce calculation accuracy
Solution Approach 1:
The patent converts the potentially harmful effect of abnormal measurement values into a beneficial filtering process. By using the discrepancy between measured and calculated values as a criterion to identify and exclude abnormal data points, the method transforms data quality issues into a systematic refinement process that improves overall measurement accuracy
Data Source
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AI summary
There is provided a simple method for calculating misalignment of a rotational body. The method for calculating misalignment of a rotational body includes the steps of: deriving radial displacement amounts of the rotational body for at least four or more measurement points along an outer surface in a circumferential direction based on measured values measured by a displacement gage while rotating the rotational body; selecting three arbitrary points among all the measurement points to calculate a calculated circle from the radial displacement amounts and rotation angles; calculating calculated circle values for all the measurement points from the calculated circle; calculating differences between the calculated circle values and the radial displacement amounts as error amounts at the measurement points; summing the error amounts to derive a total error amount value; repeating calculation for combinations of three measurement points among all the measurement points to calculate each total error amount value; selecting a calculated circle with a minimum total error amount value among obtained total error amount values for all combinations as a most probable circle; and calculating deviation between the center of the most probable circle and the center of rotation of the rotational body as misalignment data of the most probable circle.