Power Steering Abnormality Detection via Torque Frequency Analysis

Solution Overview

Problem

Existing power steering devices require an additional water drop sensor to detect abnormalities, increasing costs and complexity in the abnormality detection circuit configuration.

Innovation Solution

A power steering device uses steering torque, command signal for an electric motor, or electric current as steering force information to detect abnormalities based on periodic changes within specific frequency ranges, eliminating the need for an additional water drop sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a water drop sensor is additionally provided to detect abnormalities, then the detection accuracy is improved, but the device cost and circuit configuration complexity increase

Engineering Contradiction:

Improveabnormality detection accuracyVSAvoidcircuit configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes existing components (torque sensor, motor controller) perform multiple functions. The torque sensor not only measures steering torque for normal operation but also detects abnormal vibrations through frequency analysis. The motor controller not only controls motor current but also analyzes current fluctuations to detect water drop entry. This eliminates the need for dedicated water drop sensors and reduces circuit complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own operational parameters (steering torque, motor current) to detect abnormalities. By analyzing the frequency characteristics of these self-generated signals, the system can identify water drop entry without requiring external detection devices. The power steering device monitors itself using existing sensors and control circuits.

Inventive Principle:

Principle #25Self-service

2Measurement precision

If a water drop sensor is additionally provided to detect abnormalities, then the detection accuracy is improved, but the device cost increases

Engineering Contradiction:

Improveabnormality detection accuracyVSAvoiddevice cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent makes existing components (torque sensor, motor controller) perform multiple functions. The torque sensor not only measures steering torque for normal operation but also detects abnormal vibrations through frequency analysis. The motor controller not only controls motor current but also analyzes current fluctuations to detect water drop entry. This eliminates the need for dedicated water drop sensors and reduces circuit complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own operational parameters (steering torque, motor current) to detect abnormalities. By analyzing the frequency characteristics of these self-generated signals, the system can identify water drop entry without requiring external detection devices. The power steering device monitors itself using existing sensors and control circuits.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10392048B2Power steering device and control device therefor

Publication Date: 2019.08.27 ASTEMO LTD

AI summary

Disclosed is a power steering device 1 having a control unit 33 equipped with an abnormality detection circuit 50. The abnormality detection circuit 50 is configured to judge the occurrence of an abnormality in the power steering device when a peak level Trp of a frequency component of a steering torque Tr etc. that periodically changes in a frequency range of 20 to 25 Hz becomes higher than a predetermined value.