Magnetic Angle Sensor Error Detection via Signal Path Segmentation

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Solution Overview

Problem

Magnetic sensors in automotive steering systems face challenges due to changing sensitivity levels and nonlinearity errors caused by temperature changes, leading to inaccurate angle measurements, which can result in incorrect motor torque output and potentially hazardous steering issues.

Innovation Solution

A magnetic angle measurement system with multiple independent signal processing paths and fault detection circuitry is implemented, using a combination of anisotropic magnetoresistive and tunneling magnetoresistive sensors to determine discrepancies in angle measurements and flag errors, ensuring accurate motor control by selecting reliable angle data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple independent signal processing paths are implemented, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesensor error detection capabilityVSAvoidsignal processing paths
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system divides the sensing function into multiple independent signal processing paths (first, second, and third paths), each processing signals from different sensor combinations. This segmentation allows independent error detection for each path while maintaining overall system reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A processor acts as an intermediary that receives data from multiple signal processing paths, compares the results, and determines the final angle measurement. This intermediary component coordinates the multiple paths and resolves discrepancies between them.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple sensors and signal processing paths are used, then measurement precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveangle measurement accuracyVSAvoidsensor system assembly
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Multiple signal processing paths are designed to process signals from different sensor combinations using similar processing logic. This multi-functionality allows the system to achieve higher measurement precision through redundancy while using standardized processing approaches that simplify manufacturing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If fault detection circuitry is implemented, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidcircuitry
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The processor continuously compares angle measurements from multiple signal processing paths and provides feedback on discrepancies. When faults are detected in certain paths, the system automatically adjusts by relying on healthy paths, creating a self-monitoring feedback mechanism that improves reliability without requiring complex additional circuitry.

Inventive Principle:
Principle #23Feedback

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 system effectively detects and flags sensor errors, ensuring accurate motor control and maintaining steering functionality by determining the correct angle measurement, even in the presence of faults, thus enhancing the reliability and safety of the automotive steering system.

Implementation Method 1

A first sensor has a first plurality of outputs and a second sensor has a second plurality of outputs. The first sensor may be an anisotropic magnetoresistive sensor and the second sensor may be a tunneling magnetoresistive sensor.

Methodology Applied
Scientific EffectMagnetoresistance: Magnetoresistance

Data Source

PatentEP4182636B1Apparatus for detecting sensor error
Publication Date: 2024.06.19 ANALOG DEVICES INT UNLTD CO
  • EP4182636B1 patent drawingFigure 1A~1B
  • EP4182636B1 patent drawingFigure 2A
  • EP4182636B1 patent drawingFigure 3

AI summary

A magnetic angle measurement system having magnetic angle sensors, signal processing circuitry and a processor is disclosed. First signal processing circuitry receives a first subset of outputs of a first plurality of outputs from a first magnetic angle sensor and determines first magnetic angle data based on the received first subset of outputs. Second signal processing circuitry receives a second subset of the outputs from the first magnetic angle sensor and determines second magnetic angle data based on the received second subset of outputs. Third signal processing circuitry receives a second plurality of outputs from the second magnetic sensor and determines third magnetic angle data based on the received second plurality of outputs. The processor compares the magnetic angle data and determines a processing result based on the comparison, where fault tolerance resolution of the magnetic angle measurement system is based at least in part on the processing result.