Inductive Angle Measurement with Multi-Track Redundant Signals

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Solution Overview

Problem

Existing inductive angle measuring devices are not sufficiently accurate, compact, and cost-effective, particularly in determining the angular position of machine parts that can rotate relative to one another.

Innovation Solution

The device incorporates a scanning element with multiple receiver tracks and excitation tracks on a circuit board, featuring different period lengths and phase offsets to enhance angular position measurement accuracy and compactness, utilizing a design with fewer electrically conductive layers and a configuration that allows for high-resolution and redundant position value acquisition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple receiver tracks with different period lengths are used to achieve high-resolution angular position determination, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveangular position determination accuracyVSAvoidscanning element structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The receiver tracks are segmented into different types (first receiver track with shorter period length for high-resolution measurement, second receiver track with longer period length for coarse measurement). This segmentation allows each track to specialize in a specific measurement range, achieving high overall precision without requiring a single overly complex track design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a radial dimension by positioning receiver tracks at different radii from the rotation axis. The first receiver track is positioned at a smaller radius while the second receiver track is positioned at a larger radius. This radial arrangement allows multiple measurement functions to coexist in a compact circular footprint, reducing device complexity compared to linear arrangements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If redundant signal processing is implemented for safety-relevant applications, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsignal processing structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Different receiver tracks provide different qualities of position information: the first receiver track provides high-resolution local position data, while the second receiver track provides coarse position data with larger measurement range. The evaluation electronics selectively process signals from appropriate tracks based on the required measurement precision, optimizing reliability without uniformly increasing complexity across all signal paths.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements redundant measurement capability through multiple receiver tracks, but the evaluation electronics selectively activate and process only the necessary tracks based on the current measurement requirements. This partial action approach provides reliability through redundancy while avoiding the complexity of continuously processing all available signals.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of manufacture

If the scanning element is designed with fewer electrically conductive layers, then ease of manufacture is improved, but measurement precision may deteriorate

Engineering Contradiction:
Improvecircuit board fabricationVSAvoidangular position accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

Multiple functional elements (excitation tracks, first receiver track, second receiver track) are merged into fewer electrically conductive layers on the circuit board. This consolidation simplifies the manufacturing process and reduces fabrication complexity while the careful spatial arrangement and routing within these layers maintain the electrical performance and measurement precision required for accurate angular position determination.

Inventive Principle:
Principle #5Merging (Combining)

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

The solution provides a compact and cost-effective inductive angle measuring device with high-resolution angular position determination, ensuring accurate and reliable measurement through redundant signal processing, suitable for safety-relevant applications.

Implementation Method 1

When a temporally varying electrical excitation current is applied to the excitation tracks, position-dependent signals are generated in the receiver tracks during the relative movement between the scale element and the scanning element.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4484897B1Inductive angle measuring device
Publication Date: 2025.08.06 DR JOHANNES HEIDENHAIN GMBH
  • EP4484897B1 patent drawingFigure 1~2
  • EP4484897B1 patent drawingFigure 3~4
  • EP4484897B1 patent drawingFigure 5~7

AI summary

The invention relates to an inductive angle measuring device comprising a scanning element (1) and a scale element (2) rotatable relative to it. The scanning element (1) comprises in a first receiver track (1.1) a first receiver conductor track (1.11) and a second receiver conductor track (1.12) by which a first signal (S1.11) and a second signal (S1.12) can be generated, wherein the first and the second signal (S1.11, S1.12) have a first phase offset (PH1) to each other. The scanning element (1) further comprises a fifth receiver conductor (1.21), a sixth receiver conductor (1.22), a seventh receiver conductor (1.23), and an eighth receiver conductor (1.24), wherein the fifth and sixth receiver conductors (1.21, 1.22) are connected in series, such that a first overall signal (SU1) can be generated by the fifth and sixth receiver conductors (1.21, 1.22). Furthermore, the seventh and eighth receiver conductors (1.23, 1.24) are connected in series.24) are also connected in series, so that a second total signal (SU2) can be generated via the seventh and eighth receiver conductors (1.23, 1.24). The first total signal (SU1) and the second total signal (SU2) have a second phase offset (PH2) from each other.