Inductive Position Measurement Device Using Beating Principle
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Solution Overview
Problem
Existing inductive position measuring devices are costly and lack flexibility in determining precise absolute positions, particularly in applications requiring incremental and absolute position measurements.
Innovation Solution
The design incorporates a scale with multiple graduation tracks of slightly differing periods, paired with receiver coils of corresponding periods, utilizing the beating principle to determine absolute position through phase angle comparison, allowing for flexible use and cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the period of receiver coils is matched to the graduation period of the associated graduation track, then precise position measurement is achieved, but the device lacks flexibility and requires expensive customization for different measurement ranges
Solution Approach 1:
The patent makes the receiver coils universally applicable by designing them with a standard period that can scan multiple graduation tracks with different graduation periods. The evaluation unit adapts to different track configurations through software configuration rather than hardware customization, enabling one scanning unit to serve multiple measurement ranges and applications.
Solution Approach 2:
The patent changes the parameter matching approach from fixed (receiver coil period exactly matching graduation track period) to flexible (receiver coil period slightly different from graduation track period). This parameter deviation is compensated through evaluation algorithms that calculate absolute position based on phase angle comparisons, maintaining measurement precision while enabling versatility.
2Adaptability or versatility
If multiple graduation tracks with different graduation periods are used to extend measurement range, then adaptability is improved, but device complexity and production cost increase
Solution Approach 1:
The patent creates a universal scanning unit with receiver coils that can scan any graduation track regardless of its specific graduation period. This eliminates the need for custom-matched receiver coils for each track, simplifying the overall device structure while maintaining the capability to handle multiple measurement ranges through software configuration.
Solution Approach 2:
The patent extracts the customization requirement from the hardware level and moves it to the software evaluation level. The physical hardware (receiver coils) is standardized and simplified, while the adaptation to different measurement ranges is achieved through the evaluation unit's algorithms that process signals from any graduation track configuration.
3Loss of energy
If receiver coils with periods matching their associated graduation tracks are used, then amplitude loss is minimized, but the scanning unit cannot be flexibly assigned to different graduation tracks
Solution Approach 1:
The patent deliberately changes the parameter relationship from exact matching to slight mismatch between receiver coil period and graduation track period. This allows universal assignment of scanning units to any graduation track while the evaluation unit compensates for the parameter difference through phase angle-based absolute position calculation, maintaining measurement accuracy despite the parameter deviation.
Solution Approach 2:
The evaluation unit acts as an intermediary that bridges the parameter mismatch between receiver coils and graduation tracks. It processes the scanning signals from receiver coils with standard periods and correctly interprets them for graduation tracks with different periods by calculating phase angles and determining absolute positions through algorithmic compensation.
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 precise and flexible absolute position measurement with reduced amplitude loss due to period mismatches, supporting both length and angle measurements across various configurations.
Implementation Method 1
an excitation current impressed on the excitation coil generates an alternating electromagnetic excitation field that is influenced by the arrangement of the markings as a function of the position, as a result of which a position-dependent scanning signal is induced in the receiver coil
Data Source
Figure 1~2
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Figure 5
AI summary
PROBLEM TO BE SOLVED: To provide an induction type encoder that includes a plurality of scale tracks (11 and 12) having a plurality of electromagnetic induction type scannable marks.SOLUTION: The marks of a plurality of scale tracks (11 and 12) are arranged periodically along a measuring direction X, and a plurality of scale tracks (T1 and T2) of the plurality of scale tracks (11 and 12) are slightly different from each other. In order to generate scan signals (A1 and A2) having a signal period corresponding to periods of the scales (T1 and T2), the plurality of scale tracks (11 and 12) are scanned by a scan device (2). In this case, one reception coil (21 and 22) corresponds to each of the scale tracks (11 and 12) and periods (P1 and P2) of a plurality of reception coils (21 and 22) are identical.