ESC Brake Control Under Wheel Speed Sensor Failure
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Solution Overview
Problem
Existing Electronic Stability Control (ESC) systems in vehicles lose their attitude control function when one or more wheel speed sensors fail, compromising driving stability.
Innovation Solution
A vehicle brake system with an electronic control unit that identifies failures in wheel speed sensors and adjusts operation modes to maintain ESC functionality, including ESC available, disable, and normal modes, and provides targeted braking signals to individual wheels based on sensor availability and driving conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wheel speed sensors are used to detect wheel speed for ESC control, then the ESC function can be implemented, but the system reliability deteriorates when sensors fail
Solution Approach 1:
The system dynamically adjusts the ESC operation mode based on sensor availability. When all sensors are available, the system operates in normal mode using all wheel speed data. When one or two sensors fail, it transitions to available mode with degraded functionality. When three or more sensors fail, it switches to disable mode. This dynamic adaptation resolves the contradiction by maintaining system functionality across varying reliability conditions.
Solution Approach 2:
The system changes operational parameters (operation mode) based on sensor failure conditions. By monitoring sensor status and adjusting the operation mode accordingly, the system maintains ESC functionality when possible while safely disabling it when sensor reliability is insufficient, thus resolving the conflict between maintaining function and ensuring reliability.
2Reliability
If the ESC system deactivates attitude control function when sensors fail, then system safety is maintained, but the driving stability deteriorates
Solution Approach 1:
When one or two sensors fail, the system applies partial action by deactivating only the attitude control function while maintaining other ESC functions. This allows the system to preserve driving stability through available sensor data for basic ESC operations, while sacrificing advanced attitude control that would require all sensors to ensure safety.
Solution Approach 2:
The system dynamically adjusts the level of ESC functionality based on sensor availability. Instead of a binary on/off approach, it provides degraded functionality that maintains essential driving stability while ensuring safety by disabling functions that require complete sensor input, thus resolving the contradiction between safety and stability.
3Measurement precision
If the ESC system operates in normal mode with all sensors, then the attitude control precision is maximized, but the device complexity increases to handle multiple failure scenarios
Solution Approach 1:
The control system is segmented into distinct operation modes (normal, available, disable) based on sensor availability. Each mode has simplified control logic tailored to the specific sensor configuration, reducing the overall complexity compared to a single complex system that must handle all failure scenarios simultaneously. This segmentation allows precise attitude control in normal mode while managing complexity through mode-specific simplifications.
Data Source
AI summary
Disclosed is a brake system. The brake system includes: an electronic control unit configured to perform an attitude control function based on a wheel speed sensor value received from each of a plurality of wheel speed sensors installed in a plurality of wheels of a vehicle, identify a failure of the attitude control function, and provide a braking signal to perform the attitude control function according to the identified result; and a brake configured to perform a braking control on a corresponding wheel based on the braking signal, wherein the electronic control unit is configured to identify a failure of at least one of the plurality of wheel speed sensors while performing the attitude control function, and set an operation mode of an Electronic Stability Control (ESC) according to the identified result.