Vehicle Brake Controller Limit Control Timing Optimization
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Solution Overview
Problem
Existing vehicle brake control methods face challenges in accurately determining the onset and duration of rear-wheel lift-up during sudden braking, leading to unnecessary limit control executions that decrease vehicle deceleration and increase the risk of rear-wheel lift-up, due to disturbances from road surface variations and sensor placement issues.
Innovation Solution
A vehicle brake controller that initiates limit control based on deceleration thresholds and time periods, using a front-back direction acceleration sensor, with adjustable start and end determination values to optimize the timing of limit control and prevent unnecessary executions, while considering road gradients and braking scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the start determination value is set to a relatively small value to avoid delay in starting limit control, then the response speed of limit control is improved, but unnecessary limit control may be triggered by disturbance signals
Solution Approach 1:
The patent introduces a determination time period as a preliminary time window before actually triggering limit control. During this period, the system monitors whether deceleration continues to exceed the start determination value. Only if the condition persists throughout this period does the limit control actually start. This preliminary monitoring period filters out transient disturbance signals while maintaining sensitivity to genuine sudden braking events.
Solution Approach 2:
The patent dynamically adjusts the triggering mechanism by combining a fixed start determination value with a time-based verification process. The system adapts to different braking scenarios by requiring the deceleration condition to be sustained throughout the determination time period, effectively creating a dynamic threshold that responds differently to transient versus sustained deceleration events.
2Reliability
If the start determination value is set to a relatively large value to reduce unnecessary limit control executions, then the reliability of limit control triggering is improved, but the starting of limit control may be delayed
Solution Approach 1:
The determination time period serves as a preliminary verification window that allows the system to use a relatively large start determination value without excessive delay. By monitoring whether the deceleration condition persists throughout this period, the system can confidently trigger control when it does activate, reducing false negatives while maintaining high specificity.
3Stability of the object's composition
If limit control is executed to prevent rear-wheel lift-up, then vehicle stability is improved, but vehicle deceleration decreases due to reduced braking force on front wheels
Solution Approach 1:
The patent implements dynamic end determination by comparing current deceleration against the end determination value (which is greater than the start determination value) after the determination time period has elapsed. This dynamic approach allows limit control to be activated during genuine sudden braking events while automatically deactivating during transient disturbances, thereby minimizing the impact on overall deceleration performance while maintaining stability when truly needed.
Solution Approach 2:
The system continuously monitors deceleration signals and uses feedback from the determination time period to dynamically adjust limit control activation and deactivation. This feedback mechanism ensures that limit control is applied only when necessary, reducing unnecessary interventions that would degrade deceleration performance while maintaining vehicle stability during actual rear-wheel lift-up risks.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the decrease in vehicle deceleration caused by unnecessary limit control executions, effectively limiting rear-wheel lift-up by optimizing the timing of braking force adjustments and preventing false starts due to sensor disturbances, while ensuring proper control on varying road gradients.
Implementation Method 1
a vehicle brake controller that initiates limit control based on deceleration thresholds and time periods, using a front-back direction acceleration sensor
Data Source
AI summary
A vehicle brake controller is capable of executing limit control for limiting increase in braking force applied to front wheels by using a deceleration of a vehicle. The vehicle brake controller is configured to start the limit control when the deceleration of the vehicle becomes greater than or equal to a start determination value before a start determination time period elapses after a deceleration starting point in time, at which the deceleration of the vehicle is started by application of braking force at least to the front wheels. The vehicle brake controller is configured to end the limit control if the deceleration of the vehicle is less than an end determination value, which is greater than the start determination value, at a point in time when an end determination time period, which is longer than the start determination time period, has elapsed from the deceleration starting point in time.