Inductive Angle Sensor Error Compensation via Multi-Period Signal Segmentation

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Solution Overview

Problem

Inductive rotation angle sensors face challenges in achieving high signal quality and precise measurement results due to manufacturing and mounting tolerances, which can cause wobbling movements and misalignment between the rotor and stator, leading to measurement errors.

Innovation Solution

The design includes a printed circuit board with multiple receiver conductor tracks and a rotating dividing element with differently radiused tracks, allowing for the generation of signals with varying numbers of periods, which are combined to reduce errors from wobbling and misalignment, using an electronic circuit for signal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If receiver coils with large outside diameter are used, then sensitivity is improved, but manufacturing tolerances must be comparatively small to avoid erroneous signals

Engineering Contradiction:
Improvesignal qualityVSAvoidmounting tolerances
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent divides the single receiver coil into multiple receiver coils arranged in a specific geometric pattern. Each receiver coil processes signals from the graduation track, and their combined output provides error compensation. This segmentation allows each individual coil to have relaxed tolerance requirements while maintaining high overall measurement precision through the collective signal processing of multiple coils.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the geometric parameters of the receiver coil arrangement, specifically positioning multiple receiver coils at different radial distances from the rotation axis and at specific angular positions. By optimizing these geometric parameters, the system achieves error compensation that reduces sensitivity to manufacturing tolerances while maintaining high measurement precision.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the dividing element is positioned at different distances from the axis of rotation, then error compensation is improved, but device complexity increases

Engineering Contradiction:
Improveerror reductionVSAvoidsignal processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the signals from multiple receiver coils positioned at different radial distances through electronic addition or subtraction. This merging of signals from coils at different positions creates an error-compensated output without requiring complex mechanical adjustments. The electronic signal processing integrates information from multiple sources to achieve error reduction while maintaining relatively simple device architecture.

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

This configuration significantly improves measurement accuracy by reducing the impact of manufacturing and assembly tolerances, resulting in high signal quality and precise angular position determination.

Implementation Method 1

When a time-varying electric exciter field is applied to the excitation coils, signals dependent on the relative angular position between rotor and stator are generated in the receiver coils

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2265902B1Inductive rotational angle sensor and method for operating an inductive rotational angle sensor
Publication Date: 2014.05.07 DR JOHANNES HEIDENHAIN GMBH
  • EP2265902B1 patent drawingFigure 1
  • EP2265902B1 patent drawingFigure 2
  • EP2265902B1 patent drawingFigure 3

AI summary

The invention relates to an inductive rotational angle sensor comprising a circuit board (1) with an excitation conduction path (1.4) and a first, second and third receiver conduction path (1.1 1, 1.12, 1.21, 1.22, 1.31, 1.32) attached thereto. The rotational angle sensor further comprises a partitioning element (2) with a first and second partitioning track (2.2). The first and second partitioning track (2.1, 2.2) and the first and second receiver conduction path (1.1 1, 1.12; 1.21, 1.22) are configured such that signals (S1.1 1, S1.12) with a first period number (n1) can be produced by the first receiver conduction path (1.1 1, 1.12) and signals (S1.21, S1.22) with a second period number (n2) can be produced by the second receiver conduction path (1.21, 1.22). The partitioning element (2) further comprises a third partitioning track (2.3) so that signals (S1.31, S1.32) with the first period number (n1) can be produced by the third receiver conduction path (1.31, 1.32). The invention also comprises a method for operating a rotational angle sensor (Figure 1).