Bolt Axial Tension Measurement via Distance Sensor Rotation Compensation
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Solution Overview
Problem
Existing bolt axial tension measuring methods fail to accurately calculate axial tension due to the rotation of the bolt head during tightening, leading to inaccuracies in displacement measurements and subsequent axial tension calculations.
Innovation Solution
A bolt axial tension measuring apparatus and method that involves a distance sensor to capture distance images before and after tightening, with the image sensor's posture adjusted to match the initial orientation, allowing for accurate calculation of recess amounts and thus axial tension by compensating for the bolt's rotation angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the displacement amount of the bolt head is calculated from distance images acquired before and after tightening, then the axial tension can be measured, but the measurement precision deteriorates because the bolt head rotates during tightening causing different orientations in the distance images
Solution Approach 1:
The patent applies preliminary action by acquiring a reference distance image of the bolt head before tightening and storing its orientation information. This pre-acquired reference data allows the system to later compare against the post-tightening image, compensating for the rotation that occurs during tightening and enabling accurate displacement measurement despite the orientation change.
Solution Approach 2:
The patent implements feedback by detecting the rotation angle of the bolt head during tightening and using this information to adjust the measurement process. The system acquires the rotation angle, then uses it to properly orient or compensate for the post-tightening distance image, ensuring accurate displacement calculation by feedbacking the rotation information back into the measurement process.
2Productivity
If the distance sensor captures distance images at different orientations due to bolt rotation, then the tightening process is complete, but the measurement process becomes complex requiring additional orientation adjustment
Solution Approach 1:
The system uses feedback from the detected rotation angle to automatically adjust the measurement process. By knowing how much the bolt head rotated, the system can compensate for this in the image processing, eliminating the need for manual orientation adjustment and keeping the measurement process simple despite the dynamic tightening process.
Solution Approach 2:
The patent applies parameter changes by using the rotation angle as a corrective parameter in the measurement calculation. Instead of trying to maintain fixed orientation, the system changes the measurement approach by incorporating the rotation angle parameter to adjust the displacement calculation, simplifying the overall process while maintaining accuracy.
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
Enables precise measurement of axial tension by ensuring consistent image orientations, simplifying the measurement process and allowing for automatic tension calculation after final tightening.
Implementation Method 1
a distance sensor configured to measure a distance to a head of the bolt and to acquire a distance image in which the distance thus measured is indicated by a pixel value
Data Source
AI summary
At a first timing when a tightening machine temporarily tightens a bolt, a distance sensor acquires a first distance image. A distance sensor controller measures a first recess amount of the head of the bolt at the first timing by the first distance image. A manipulator controller is configured to change a relative posture of an image sensor relative to the head of the bolt in accordance with a rotation angle by which the bolt is rotated from the first timing to a second timing. The distance sensor acquires a second distance image at the second timing, and the distance sensor controller measures a second recess amount of the head of the bolt at the second timing by the second distance image, so as to measure an axial tension of the bolt by use of a difference between the first recess amount and the second recess amount.