Dynamic Slip Rate Threshold ABS Control for Vehicle Stability
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Solution Overview
Problem
Existing vehicle ABS control systems fail to fully utilize ground braking force and often result in wheel lockup during turns due to the use of constant slip rate thresholds and a two-wheel vehicle model, which does not account for varying sideslip angles between wheels.
Innovation Solution
A vehicle ABS control system and method that sets real-time slip rate thresholds based on individual wheel sideslip angles, using a four-wheel vehicle model to apply separate ABS control to each wheel, ensuring optimal braking force distribution and preventing wheel lockup by comparing calculated slip rates with dynamically set thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant slip rate threshold is used for ABS control, then the control system is simple to implement, but the wheels cannot take full advantage of ground braking force and wheel lockup occurs during turning
Solution Approach 1:
The patent applies dynamics by transitioning from a constant slip rate threshold to a dynamic, variable threshold that adapts to real-time driving conditions. The system calculates individual wheel sideslip angles and adjusts each wheel's slip rate threshold accordingly, enabling the ABS control to respond to varying road adhesion and vehicle motion states, thereby preventing wheel lockup while maximizing braking force utilization.
Solution Approach 2:
The patent implements parameter changes by modifying the slip rate threshold from a fixed constant to a variable parameter that changes based on measured sideslip angles and calculated adhesion coefficients. This allows the control system to optimize braking performance across different driving scenarios, including straight-line braking and turning maneuvers, where optimal slip rates differ significantly.
2Device complexity
If a two-wheel vehicle model is used for ABS control, then the control system is simpler, but it cannot account for different sideslip angles between wheels during turning
Solution Approach 1:
The patent applies segmentation by dividing the vehicle into four independent wheel units, each with its own sideslip angle calculation and ABS control parameters. Instead of treating the vehicle as a single two-wheel unit, the system individually processes data for each wheel, allowing precise control that accounts for the different kinematic conditions experienced by inner and outer wheels during turning maneuvers.
Solution Approach 2:
The patent implements local quality by assigning unique control parameters to each wheel based on its specific operating conditions. Each wheel receives a customized slip rate threshold derived from its individual sideslip angle and measured adhesion coefficient, rather than applying a uniform threshold across all wheels. This localized control optimizes braking performance for each wheel's specific contact patch conditions.
3Reliability
If real-time variable slip rate thresholds are set based on individual wheel sideslip angles, then wheel lockup is prevented and braking force is optimized, but the control system complexity increases
Solution Approach 1:
The patent applies self-service by enabling the ABS system to automatically calculate and adjust its own control parameters without external intervention. The system continuously measures wheel speeds and vehicle motion, computes individual wheel sideslip angles and adhesion coefficients, and autonomously determines optimal slip rate thresholds for each wheel, making the complexity management self-contained.
Solution Approach 2:
The patent implements feedback by continuously monitoring wheel speed, calculating sideslip angles, measuring adhesion coefficients, and using this information to dynamically adjust slip rate thresholds. This closed-loop control ensures that the system responds to changing road conditions and vehicle states in real-time, maintaining optimal braking performance while adapting to varying friction conditions.
Data Source
AI summary
An anti-skid brake control system and its control method for vehicle has a signal collection unit and an electronic control unit. The electronic control unit includes a data receiving module, a data processing module and a data control module. The data receiving module receives the data collected by the signal collection unit. The data processing module calculates sideslip angles and slip rates for wheels. The data control module sets target slip rates based on the slip rates corresponding to the friction coefficient μ for different sideslip angles. The device emits control commands after comparing the calculated slip rate to the set target slip rate, so that the ABS control is real time.