Vehicle Wheel Speed Sensor Abnormality Detection Using Brake Force
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Solution Overview
Problem
Existing vehicle wheel speed sensor abnormality detection methods are inadequate, particularly when wheel slip occurs, leading to reduced accuracy in determining sensor abnormalities, especially when sensor values approach zero, causing normal values to be misinterpreted.
Innovation Solution
An abnormality information generating apparatus that determines sensor rationality by applying brake force and monitoring vehicle body speed, identifying if only one wheel speed sensor value is below a threshold, while others are not, using a processing device to generate information representing sensor rationality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wheel speed sensor abnormality is determined based on the difference between first vehicle speed (from wheel speed sensors) and second vehicle speed (from transmission output shaft rotation speed), then abnormality detection is provided, but detection accuracy is reduced when wheel slip occurs causing large speed differences even with normal sensors
Solution Approach 1:
The patent changes the detection parameters by introducing multiple comparison thresholds (first threshold and second threshold) instead of a single threshold. The first threshold compares the absolute difference between first and second vehicle speeds, while the second threshold compares the difference between left and right wheel speeds. This multi-parameter approach allows the system to distinguish between speed differences caused by wheel slip versus those caused by sensor abnormalities, thereby resolving the contradiction between detection reliability and measurement precision.
2Difficulty of detecting and measuring
If vehicle speed information is used to determine sensor abnormality, then sensor monitoring is achieved, but false abnormality detection occurs when wheel slip causes speed differences even with normal sensors
Solution Approach 1:
The patent segments the abnormality detection process into two distinct comparison stages: first comparing the overall vehicle speed difference (first vehicle speed vs. second vehicle speed) against a first threshold, and then comparing the individual wheel speed difference (left wheel speed vs. right wheel speed) against a second threshold. This segmentation allows the system to systematically eliminate false positives by requiring both conditions to be satisfied, thereby improving detection accuracy while maintaining detection capability.
3Measurement precision
If only vehicle stopped state is used for abnormality detection, then wheel slip interference is avoided, but abnormality detection in moving state is lost and sensor values near zero are misinterpreted as normal
Solution Approach 1:
The patent implements a dynamic detection system that adapts to different vehicle operating states. By continuously monitoring both speed difference parameters (first threshold for vehicle speed and second threshold for wheel speed) during vehicle operation, the system can dynamically identify sensor abnormalities regardless of whether the vehicle is stopped or moving. This dynamic approach replaces the static vehicle-stopped-only condition, maintaining measurement precision while significantly improving adaptability to various operating conditions.
Data Source
AI summary
An abnormality information generating apparatus is disclosed that generates information representing a rationality related to a plurality of vehicle wheel speed sensors that are installed at wheels of a vehicle, respectively. The abnormality information generating apparatus includes a processing device configured to generate the information when (1) a brake force is applied to the wheels, (2) a vehicle body speed based on a rpm of a rotation member is greater than a first threshold, the rotation member being common to drive wheels and being configured to transmit drive force to the drive wheels, and (3) only arbitrary one of the vehicle wheel speed sensors has a detected value smaller than a second threshold, the second threshold being smaller than the first threshold.