Braking Control Device for Low Friction Regions
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Solution Overview
Problem
Existing braking control systems, such as ABS, often intervene unnecessarily in low friction coefficient regions, leading to abrupt deceleration changes and discomfort for occupants, especially during automated driving.
Innovation Solution
A braking control device that includes a target vehicle speed setting unit, a braking power control unit, and a low friction coefficient region recognition unit, which adjusts the start of braking and deceleration rate to prevent ABS intervention by delaying or reducing braking power in low friction areas, ensuring smooth deceleration and reducing discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ABS control is applied during braking in low friction coefficient regions, then wheel locking is prevented, but abrupt deceleration changes occur causing occupant discomfort
Solution Approach 1:
The low friction coefficient region recognition unit detects low friction regions ahead of the vehicle before braking occurs. The system proactively adjusts braking control parameters in advance when entering such regions, preventing ABS intervention by reducing braking power before wheel locking symptoms appear, thereby avoiding abrupt deceleration changes and occupant discomfort while maintaining wheel locking prevention capability
Solution Approach 2:
The braking control system dynamically adjusts braking power based on real-time recognition of low friction coefficient regions. When such regions are detected, the system reduces braking power and modifies deceleration rate profiles adaptively, allowing smooth deceleration that prevents ABS activation while maintaining effective braking control in varying road conditions
2Speed
If braking power is increased to achieve faster deceleration, then stopping distance is reduced, but wheel locking occurs causing loss of steering control
Solution Approach 1:
The system detects low friction coefficient regions in advance and proactively reduces braking power before the vehicle enters these regions. This preliminary adjustment prevents wheel locking by ensuring braking force remains below the reduced friction threshold, maintaining steering control while still achieving effective deceleration through optimized braking profiles
Solution Approach 2:
The braking control device changes braking power parameters dynamically based on recognized low friction regions. By adjusting braking power to be lower in low friction areas and modifying deceleration rate profiles, the system achieves optimal balance between deceleration performance and preventing wheel locking, thereby maintaining steering control throughout the braking process
3Object-affected harmful factors
If braking starts earlier to account for low friction regions, then stopping distance increases, but deceleration smoothness is improved
Solution Approach 1:
The low friction coefficient region recognition unit identifies low friction regions ahead of the vehicle. The braking control device uses this advance information to optimally time the reduction of braking power, starting the adjustment at the precise moment of entry into the low friction region. This timing optimization achieves smooth deceleration without unnecessarily extending stopping distance, as braking power is reduced only when and where needed
Data Source
AI summary
A braking control device includes a target vehicle speed setting unit, a braking power control unit, and a low friction coefficient region recognition unit. The low friction coefficient region recognition unit recognizes a low friction coefficient region of a road surface between a current position of an own vehicle and a target position. The braking power control unit estimates a maximum deceleration rate assuming braking to be started after passage through the low friction coefficient region to cause deceleration to a target vehicle speed at the target position. On the condition that the maximum deceleration rate is smaller than a predetermined upper limit on a deceleration rate, the braking power control unit causes a start of generation of braking power after the passage through the low friction coefficient region.