Hall Sensor Torque Detection Circuit Redundancy

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Solution Overview

Problem

Existing sensor devices for vehicle power steering systems face challenges in determining abnormality in steering torque signals due to power supply circuit issues, leading to incomplete abnormality determination and potential safety risks.

Innovation Solution

A sensor device with a configuration of four detecting units and two power supply circuits, where a control device compares output signals from pairs of detecting units to determine abnormality, ensuring continued abnormality determination even if one power supply circuit fails, using processor cores and signal transmission units to specify and manage abnormal signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If all detecting units are operated by power from one power supply circuit, then device complexity is reduced, but reliability deteriorates because abnormality determination cannot be correctly performed when the power supply circuit fails

Engineering Contradiction:

Improvepower supply circuit configurationVSAvoidabnormality determination accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The power supply system is segmented into multiple independent power supply circuits (first power supply circuit and second power supply circuit), each supplying power to different detecting units. This segmentation ensures that a failure in one power supply circuit does not affect the operation of detecting units powered by other circuits, thereby maintaining abnormality determination capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different detecting units are assigned to different power supply circuits based on their function and location in the abnormality determination process. The first and second detecting units are powered by the first power supply circuit, while the third and fourth detecting units are powered by the second power supply circuit, creating local quality differences that enhance overall system reliability.

Inventive Principle:

Principle #3Local quality

2Reliability

If detecting units are divided into groups powered by different power supply circuits, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveabnormality determination continuityVSAvoidpower supply circuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Each power supply circuit is designed to supply power to multiple detecting units (first power supply circuit supplies to first and second detecting units, second power supply circuit supplies to third and fourth detecting units), making each power supply circuit multi-functional and reducing the need for additional dedicated power supply components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses multiple detecting units that are essentially copies of the same detection mechanism, each powered by different power supply circuits. This copying approach allows redundancy without requiring fundamentally different components, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #26Copying

3Device complexity

If only two detecting units are used for abnormality determination, then device complexity is reduced, but reliability deteriorates because continuous abnormality determination cannot be ensured when one power supply circuit fails

Engineering Contradiction:

Improvenumber of detecting unitsVSAvoidcontinuous abnormality determination capability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The abnormality determination process uses an asymmetric configuration where the first abnormality determining unit compares outputs from detecting units powered by the first power supply circuit, while the second abnormality determining unit compares outputs from detecting units powered by the second power supply circuit. This asymmetric design ensures that each determination path has independent power supply protection.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The system prepares multiple detecting units and power supply circuits in advance, so that when one power supply circuit fails, the other detecting units already in place can immediately take over the abnormality determination function without interruption, providing beforehand cushioning against power supply failures.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS10933907B2Sensor device

Publication Date: 2021.03.02 ASTEMO LTD

AI summary

The present invention includes: first to fourth Hall elements for detecting steering torque; a first power supply circuit for supplying power to the first and second Hall elements; a second power supply circuit for supplying power to the second and third Hall elements; and a control device including a first abnormality determining unit for determining whether first and fourth torque signals are abnormal by preparing the first torque signal output from the first Hall element with the fourth torque signal output from the fourth Hall element and a second abnormality determining unit for determining whether second and third torque signals are abnormal by comparing the second torque signal output from the second Hall element with the third torque signal output from the third Hall element. With this, even when abnormality occurs in one of the first and second power supply circuits, the abnormality determination of an output signal can be continued.