Brake Control Continuity After Wheel Speed Sensor Failure
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Solution Overview
Problem
Existing vehicle braking systems face challenges in maintaining effective brake control functions when wheel speed sensors fail, leading to deactivation of critical safety features like post-crash braking, which compromises vehicle safety and stability.
Innovation Solution
A method that continues brake control functions for a defined period after detecting a wheel speed sensor failure, allowing for continued deceleration and informing the driver, with optional partial release of the affected wheel brake to prevent blocking, and deactivation only when the function completes or no further control is needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brake control functions are deactivated upon sensor failure, then system reliability is improved by preventing unsafe operation, but availability of brake control functions deteriorates
Solution Approach 1:
The system dynamically adjusts its operational state based on the timing and context of sensor failure. When a sensor fails during active brake control function execution, the system transitions to a degraded mode that allows continued operation. When failure occurs during idle periods, the system deactivates the function. This dynamic response resolves the contradiction by adapting system behavior to operational context.
Solution Approach 2:
The system changes the operational parameter of brake control function availability based on the system state (active vs. idle). During active braking operations, the parameter is set to allow continued function execution despite sensor failure. During idle periods, the parameter is set to deactivate the function. This parameter-based approach enables the system to maintain reliability while preserving functionality when appropriate.
2Object-affected harmful factors
If the affected wheel is excluded from brake control, then wheel blocking is prevented, but deceleration power is reduced
Solution Approach 1:
Instead of completely excluding the affected wheel from brake control, the system applies partial braking force to the wheel with sensor failure. This partial action is sufficient to prevent wheel blocking while maintaining overall deceleration power. The compromise allows the system to address the harmful effect (blocking) without fully sacrificing the beneficial effect (deceleration power).
3Adaptability or versatility
If brake control function continues after sensor failure, then availability is improved, but system complexity increases
Solution Approach 1:
The system performs preliminary assessment of the operational context when sensor failure occurs. By evaluating whether a brake control function is currently active or idle before deciding whether to continue or deactivate the function, the system avoids complex continuous monitoring and decision-making logic. This preliminary action simplifies the overall control structure while maintaining functionality.
Data Source
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AI summary
The invention relates to a method for controlling a vehicle's braking system, wherein the braking system has at least one wheel brake for each vehicle wheel. Sensors are provided for the wheel brakes to determine the wheel speeds of the vehicle wheels. The braking system is configured to execute brake control functions based on the wheel speeds determined by the sensors. The method includes detecting a failure of the sensors for at least one of the vehicle wheels and checking whether a brake control function is being executed by the braking system at the time of the failure. If a brake control function is being executed by the braking system at the time of the failure, the method includes continuing the brake control function and deactivating the brake control function when its execution is complete.If no brake control function is executed by the brake system at the time of the failure, the procedure includes checking whether a brake control function is triggered within a defined time period after the time of the failure. If a brake control function is triggered within the defined time period after the time of the failure, the procedure provides for the execution of the brake control function. Furthermore, the procedure includes deactivating the brake control function when the execution of the brake control function is complete and the time period has expired, or if no brake control function has been triggered within the defined time period after the time of the failure.