2D Code Pattern Position Sensor Deviation Detection
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Solution Overview
Problem
Existing systems for determining positions along a direction of advance face challenges in accurately determining absolute positions and deviations from ideal positions, particularly when there are unintentional movements or orientations of sensors relative to patterns, leading to reduced measurement accuracy and increased design complexity.
Innovation Solution
A system utilizing a two-dimensional pattern scanned by a line sensor with code words that encode both absolute positions and deviations, allowing for precise determination of positions and discrepancies in multiple degrees of freedom without requiring additional position finding means or complex calibration methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If incremental position finding systems are used, then the system can determine position changes, but the system requires restart from zero position and cannot determine absolute position
Solution Approach 1:
The patent combines incremental position encoding (pattern elements at regular intervals) with absolute position encoding (unique pattern sequences) into a single integrated pattern structure. This allows the sensor to simultaneously determine both position changes and absolute position without requiring system restart, resolving the contradiction between measurement precision and ease of operation.
Solution Approach 2:
The pattern design enables the same pattern structure to serve multiple functions: it provides incremental position information for measuring position changes and absolute position information for determining exact location. This multi-functionality eliminates the need for separate systems and allows operation without restart from zero position.
2Measurement precision
If absolute position finding systems are used, then the system can determine absolute position immediately, but the system cannot determine deviations from ideal sensor position
Solution Approach 1:
The pattern is segmented into multiple functional regions: some pattern elements encode absolute position information while other elements encode sensor orientation and position deviation information. This segmentation allows simultaneous determination of both absolute position and sensor deviation without information loss.
3Measurement precision
If complex calibration methods are used to compensate for sensor deviations, then measurement accuracy can be maintained, but device complexity increases
Solution Approach 1:
The pattern enables the system to self-calibrate by encoding deviation information directly in the pattern structure. The sensor determines its own deviation from ideal position by analyzing the scanned pattern, eliminating the need for external calibration equipment or complex calibration procedures while maintaining measurement accuracy.
4Measurement precision
If additional position finding means are added to determine sensor deviation, then measurement accuracy is maintained, but device complexity and cost increase
Solution Approach 1:
The single pattern structure serves multiple functions: it provides absolute position encoding, incremental position encoding, and sensor deviation encoding. This eliminates the need for additional position finding means or separate calibration patterns, reducing device complexity and cost while maintaining the ability to determine both position and sensor deviation accurately.
Data Source
AI summary
System for determining positions along a direction of advance, having a first sensor, particularly a line sensor, having a scanning length (L) for scanning a first 2D pattern and producing a scan signal. The first 2D pattern has pattern elements that each form a first code word on at least one portion of the scanning length (L), which first code word codes a position along the direction of advance absolutely. In addition, the first code word can be taken as a basis for determining a deviation from an ideal position for the first sensor in relation to the first 2D pattern.