Brake Fluid Pressure Control Device with Dynamic Threshold Adjustment

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Solution Overview

Problem

Existing brake fluid pressure control systems lack precision in determining bad road conditions due to constant determination conditions, which can lead to suboptimal braking control.

Innovation Solution

A brake fluid pressure control device that includes wheel speed acquisition, slippage amount calculation, and bad road determination means, which adjusts the bad road determination threshold value based on wheel slippage to improve precision, using the deviation between estimated vehicle body speed and wheel speed to detect road surface conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If constant determination conditions are used for bad road detection, then the device complexity is reduced, but the measurement precision of road surface state deteriorates

Engineering Contradiction:
Improvedetermination condition complexityVSAvoidroad surface state detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the determination threshold dynamic rather than constant. The threshold is adjusted in real-time based on the detected wheel slippage amount, allowing the system to adapt to varying braking conditions and road surfaces, thereby improving detection precision without requiring overly complex fixed thresholds for every possible condition

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the determination threshold based on the slippage amount. By modifying the threshold value according to actual wheel behavior (slippage), the system achieves more accurate bad road detection across different braking scenarios without increasing overall device complexity

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the bad road determination threshold value is increased to reduce false positives, then the reliability of normal braking is improved, but the measurement precision of actual bad roads deteriorates

Engineering Contradiction:
Improvenormal braking reliabilityVSAvoidbad road detection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent dynamically adjusts the determination threshold parameter based on slippage amount. During normal braking with low slippage, a higher threshold prevents false positives. During actual bad road conditions with high slippage, the threshold automatically lowers to detect the true condition, thus resolving the contradiction between reliability and precision

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the bad road determination threshold value is decreased to improve detection sensitivity, then the measurement precision of bad roads is improved, but false positives increase reducing normal braking reliability

Engineering Contradiction:
Improvebad road detection precisionVSAvoidnormal braking reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses slippage amount as a basis for dynamically changing the threshold parameter. This ensures that low thresholds (high sensitivity) are only applied when slippage indicates actual bad road conditions, while normal braking with low slippage maintains higher thresholds, preventing false positives

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If constant determination conditions are used, then the ease of operation is improved, but the adaptability to different braking powers and road conditions deteriorates

Engineering Contradiction:
Improvedetermination condition simplicityVSAvoidadaptability to braking conditions
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements self-service by having the system automatically adjust its own determination threshold based on detected slippage. The system serves itself by using its own operational data (wheel speed, slippage) to adaptively change its determination conditions, eliminating the need for complex external configuration while improving adaptability

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3446937B1Brake fluid pressure control device for vehicle
Publication Date: 2022.11.02 ASTEMO LTD
  • EP3446937B1 patent drawingFigure 1
  • EP3446937B1 patent drawingFigure 2~3
  • EP3446937B1 patent drawingFigure 4

AI summary

The invention relates to a brake fluid pressure control device for a vehicle capable of performing fluid pressure control of a brake fluid pressure applied to a wheel brake, the brake fluid pressure control device comprising: wheel speed acquisition means that acquires a wheel speed; slippage amount calculation means that calculates a slippage amount of a wheel; and bad road determination means that determines whether a state of a traveling road surface is bad, wherein the bad road determination means determines whether the state of the traveling road surface is bad using a value related to wheel behavior calculated based on at least the wheel speed and a bad road determination threshold value, and changes the bad road determination threshold value according to the slippage amount of the wheel.