EMB Brake Control Under Wheel Speed Sensor Failure
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Solution Overview
Problem
Conventional brake systems fail to operate ABS control when at least one wheel speed sensor fails, leading to instability on Split_mu road surfaces.
Innovation Solution
A brake system that utilizes Electro Mechanical Brakes (EMBs) and a processor to control braking forces in response to sensor failures, including identifying failed wheel speed sensors and adjusting braking forces accordingly to maintain stability on various road surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ABS control is used with wheel speed sensors, then ABS control operates normally on uniform road surfaces, but the system fails to operate when wheel speed sensors fail
Solution Approach 1:
The processor identifies sensor failures in advance and switches to alternative control strategies using data from functional sensors. By detecting sensor status beforehand and preparing backup control logic, the system maintains ABS functionality even when some wheel speed sensors fail, resolving the contradiction between normal operation reliability and adaptability to sensor failure.
2Productivity
If braking force is increased rapidly to prevent wheel lockup, then braking effectiveness improves, but stability deteriorates on Split_mu road surfaces
Solution Approach 1:
The system applies different braking control strategies to different wheels based on their individual sensor status and detected road conditions. When a sensor fails, the processor adjusts braking force distribution locally at affected wheels while maintaining appropriate braking at other wheels, preventing overall vehicle instability while preserving braking effectiveness through localized adaptation.
Solution Approach 2:
The braking control system dynamically adjusts braking force based on real-time sensor data and detected wheel slip conditions. The processor continuously monitors wheel speed changes and modulates braking force accordingly, increasing or decreasing pressure as needed to maintain both braking effectiveness and vehicle stability on varying road surfaces including Split_mu conditions.
3Device complexity
If ABS control is disabled when sensors fail, then system complexity is reduced, but braking performance and stability are compromised
Solution Approach 1:
The brake system performs self-diagnosis by monitoring sensor functionality and automatically switches to alternative control modes when sensor failures are detected. The processor uses data from functional sensors to infer wheel speed information for failed sensors and maintains ABS control without requiring manual intervention or system shutdown, thus maintaining braking performance without significantly increasing system complexity.
Data Source
AI summary
A brake system may include: a first electro mechanical brake configured to brake a first wheel of a vehicle; a second electro mechanical brake configured to brake a second wheel of the vehicle; and a processor configured to output a signal for controlling the first electro mechanical brake and the second electro mechanical brake to brake the first wheel and the second wheel, in response to reception of a signal output from a pedal sensor of a brake pedal of the vehicle, wherein the processor may be configured to output, as a result of identifying that a first wheel speed sensor provided in the first wheel has failed, a signal for controlling the first electro mechanical brake to brake the first wheel in response to an elapse of a preset time after the reception of the signal output from the pedal sensor.