Displacement Measuring Device Using Pattern Circulation
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Solution Overview
Problem
Conventional displacement and deflection angle measurement methods require high precision patterns and systems with low distortion, making them costly and complex to implement effectively.
Innovation Solution
A displacement measuring device with a pattern projecting unit and a pattern image pickup unit that circulates and updates a displacement detecting pattern, allowing for precise measurement of displacement by dividing the displacement amount by the number of circulations, while reducing the influence of distortion through controlled image rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high precision pattern and low distortion optical system are used for displacement measurement, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The measurement process is segmented into multiple circulation cycles, where the total displacement is divided into N incremental measurements. Each cycle measures a portion of the total displacement, allowing the system to achieve high precision through accumulation rather than requiring a single high-precision measurement setup.
Solution Approach 2:
The pattern is circulated periodically N times through the measurement system. This periodic circulation allows the displacement measurement to be accumulated across multiple cycles, enabling fine displacement measurement while using a simpler optical system that doesn't require extremely low distortion specifications.
2Measurement precision
If a high precision pattern is used for displacement measurement, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The measurement precision is achieved through segmentation of the measurement process into N circulation cycles rather than requiring a single high-precision pattern. This allows the use of a simpler, easier-to-manufacture pattern that is circulated multiple times to accumulate measurement data.
Solution Approach 2:
The pattern is copied and circulated N times through the measurement system. Instead of requiring a single high-precision master pattern, the system uses a simpler pattern that is repeatedly circulated and measured, accumulating displacement information across multiple cycles to achieve high measurement precision.
3Measurement precision
If the image pickup and projection systems have low distortion, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The pattern circulation is performed periodically N times, allowing the measurement system to accumulate displacement data across multiple cycles. This periodic action enables the use of optical systems with higher acceptable distortion levels, as the cumulative measurement across N cycles compensates for individual measurement errors.
Solution Approach 2:
The system changes the parameter of number of circulation cycles from 1 to N, transforming the measurement approach from a single high-precision measurement to multiple accumulated measurements. This parameter change allows the optical system to have higher distortion tolerance while maintaining high measurement precision through mathematical accumulation.
Data Source
AI summary
A displacement measuring device, comprising a pattern projecting unit, a pattern image pickup unit capable of relatively displacing with respect to the pattern projecting unit and a control unit, wherein the pattern projecting unit projects a displacement detecting pattern to the pattern image pickup unit, the pattern image pickup unit picks up the displacement detecting pattern as projected, the control unit circulates image of the displacement detecting pattern picked up by the pattern image pickup unit to the pattern projecting unit, updates the displacement detecting pattern projected by the pattern projecting unit to the displacement detecting pattern as circulated, and projects the displacement detecting pattern as updated to the pattern image pickup unit, wherein relative displacement between the pattern projecting unit and the pattern image pickup unit is obtained by dividing a displacement amount of the displacement detecting pattern in the image acquired by circulation by the number of circulations.