Sensor Device Signal Segmentation for Steering Abnormality Detection

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Solution Overview

Problem

Existing sensor systems for electric power steering apparatuses lack effective methods to determine abnormality in sensor devices and communication line short-circuits, making it difficult to identify faulty sensors and communication issues.

Innovation Solution

A sensor device with a first and second sensor part, each comprising a main and sub sensor element, generates output signals that include both main and sub signals, allowing a controller to determine abnormality by comparing these signals, and includes a signal obtainer and abnormality determiner to identify faulty sensors and communication line issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two torque sensors are provided with one monitoring the other, then sensor redundancy is improved, but the ability to determine which sensor has abnormality or detect communication line short-circuits deteriorates

Engineering Contradiction:

Improvesensor redundancyVSAvoidabnormality determination

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

Each sensor part is segmented into a main sensor element and a sub sensor element, with each element having its own output circuit. The output signals are further segmented into main signals and sub signals arranged in specific sequences, allowing the controller to analyze individual signal components to determine abnormalities in specific sensors or communication lines.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first and second sensor parts are configured with asymmetric signal arrangements where one sensor outputs main signal then sub signal, while the other outputs sub signal then main signal. This asymmetric configuration allows the controller to distinguish between sensor failures and communication line short-circuits by comparing the signal patterns from each sensor part.

Inventive Principle:

Principle #4Asymmetry

2Measurement precision

If four sensor elements are used with separate output circuits, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvesensor detection accuracyVSAvoidsensor device structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Each sensor part contains both a main sensor element and a sub sensor element that detect the same physical quantity, making them universally functional for the same measurement purpose. This multi-functionality allows the system to achieve high measurement precision through comparison while maintaining a relatively compact device structure by using identical sensor types in different configurations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10300944B2Sensor device and electric power steering apparatus using same

Publication Date: 2019.05.28 DENSO CORP

AI summary

A sensor device including a first output circuit generating and outputting a first output signal that is generated as a signal sequence from a first main signal based on a detection value of a first main sensor element to a first sub signal based on a detection value of a first sub sensor element, a second output circuit generating and outputting a second output signal that is generated as a signal sequence from a second main signal based on a detection value of a second main sensor element to a second sub signal based on a detection value of a second sub sensor element, and an abnormality determiner determining abnormality of the device based on the first output signal and the second output signal.