Position Measuring Device Complementary Code Elements
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Solution Overview
Problem
Existing absolute position measuring devices have a low degree of modulation and complex evaluation due to their design, making it difficult to generate a correct absolute position with high reliability.
Innovation Solution
A position measuring device with a code carrier featuring code elements composed of complementary sub-areas, where detectors scan these elements and a periodic incremental graduation to generate scanning signals that are combined to form a periodic incremental signal, enhancing modulation and simplifying evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single detector scans the code track and incremental scale, then the device structure is simple, but the modulation level is low and evaluation is complex
Solution Approach 1:
The code elements are divided into two complementary sub-sections (first and second sub-sections) that are scanned by separate detectors. This segmentation allows each detector to focus on specific signal characteristics, improving the modulation level of the sampled signals while maintaining a relatively simple overall device structure.
Solution Approach 2:
The evaluation unit combines the sampling signals from both detectors to generate the final evaluation result. By merging the signals from the two complementary sub-sections, the system achieves higher modulation levels and more reliable position determination compared to using a single detector.
2Reliability
If complementary sub-sections are used in code elements, then the modulation level increases, but the code track complexity increases
Solution Approach 1:
Different regions of the code track (first and second sub-sections of each code element) are designed with complementary local properties. This local differentiation increases the modulation level for position detection while keeping the overall code track structure systematic and manageable.
Solution Approach 2:
The code elements use asymmetric complementary sub-sections with inverse properties rather than symmetric patterns. This asymmetry enhances the modulation characteristics of the scanned signals, improving reliability while the repetitive pattern across code elements maintains structural regularity.
3Measurement precision
If multiple detectors scan complementary sub-sections, then the sampling signal quality improves, but the device complexity increases
Solution Approach 1:
The scanning function is segmented between two detectors, each responsible for scanning one of the complementary sub-sections of code elements. This segmentation improves sampling signal quality by allowing each detector to optimize for its specific sub-section while the evaluation unit integrates both signals.
Solution Approach 2:
Both detectors perform the same basic scanning function but on different complementary sub-sections, creating a universal detector design that can be easily replicated and integrated. The evaluation unit universally processes both signals through the same combination logic, simplifying the overall system architecture despite using multiple detectors.
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 allows for precise absolute position measurement with improved reliability and increased modulation, enabling accurate interpolation and code information formation.
Implementation Method 1
For particularly advantageous optical scanning, the two sub-areas of a code element each have complementary optical properties, thus transparent and non-transparent sub-areas in transmitted light scanning, and reflective and non-reflective sub-areas in reflected light scanning.
Data Source
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AI summary
The device has a code carrier (1) with a sequence of code elements including portions (C1A-C4A) and other portions (C1B-C4B) with complementary characteristics relative to each other. A sampling device includes detectors (D1, D2) for common sampling of the respective portions (C1A, C1B) of one of the code elements and incremental division such that respective sampling signals (A1, A2) are produced. An evaluating unit (3) is associated to the sampling signals, and forms a code information for one of the code elements and a periodical incremental signal (I1).