Workpiece Position Sensing With Multi-Angle Illumination
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Solution Overview
Problem
Existing methods for determining the position and alignment of workpieces in industrial processing face challenges due to shadowing effects caused by workpiece geometry, which can lead to inaccurate detection and alignment, especially when using a single radiation source for structured illumination.
Innovation Solution
A device and method utilizing a pair of radiation sources or a beam splitter to direct electromagnetic radiation from different directions onto overlapping areas of the workpiece surface, reducing or avoiding shadowing effects, and employing a sensor unit with a mirror arrangement to detect radiation from different perspectives, allowing for more accurate triangulation-based position determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single radiation source is used for structured illumination, then the device complexity is reduced, but shadowing effects occur leading to reduced measurement precision
Solution Approach 1:
The single radiation source is segmented into multiple radiation sources (first radiation source and second radiation source) positioned at different locations. Each source illuminates the workpiece from a different direction, which eliminates shadowing effects while maintaining manageable device complexity through modular configuration.
Solution Approach 2:
The illumination approach transitions from a single-point source to a multi-dimensional arrangement with radiation sources positioned at different spatial coordinates. This dimensional expansion allows radiation to reach previously shadowed areas from alternative angles, improving measurement precision without excessive complexity increase.
2Measurement precision
If radiation sources are positioned to illuminate from different directions, then shadowing effects are reduced, but the device complexity increases
Solution Approach 1:
Multiple radiation sources and their associated optical components are merged into an integrated measuring unit that moves together. This combining approach consolidates the complexity management while maintaining the beneficial multi-directional illumination geometry for reduced shadowing and improved precision.
Solution Approach 2:
The measuring unit incorporating multiple radiation sources is designed to perform multiple functions: position determination, alignment verification, and shadowing compensation. This multi-functionality justifies the increased device complexity by delivering comprehensive measurement capabilities from a single integrated system.
3Device complexity
If a single sensor position is used for detection, then the device complexity is reduced, but detection accuracy is limited due to shadowing
Solution Approach 1:
The detection system is segmented into multiple sensors (first sensor and second sensor) positioned at different locations relative to the workpiece. Each sensor detects reflected radiation from its specific viewpoint, and the processing unit combines these multiple detection signals to reconstruct accurate position and alignment information, overcoming the limitations of single-point detection.
4Measurement precision
If alignment verification is performed with multiple reflection tracks, then measurement precision is improved, but processing complexity increases
Solution Approach 1:
The processing unit implements a feedback mechanism that compares the detected reflection tracks against expected geometric relationships. When deviation exceeds a threshold, the system generates an error signal that feeds back to the positioning system for correction. This closed-loop feedback approach manages processing complexity by focusing computational effort only on correcting identified deviations rather than processing all data exhaustively.
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 more precise detection of workpiece position and alignment, reducing errors and allowing for direction-independent processing by generating a beam curtain with multiple measuring units, which simplifies alignment and maintains consistent distance between the processing unit and workpiece.
Implementation Method 1
detect electromagnetic radiation emitted by the radiation source or sources and reflected on a surface of the workpiece
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a
AI summary
The invention also relates to a device and a method for determining a position and/or orientation of a workpiece relative to a machining unit.