Braking Pressure Differential Control for Vehicle Stability
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Solution Overview
Problem
Vehicle braking systems face challenges in maintaining driving stability while achieving a short braking distance on μ-split road surfaces, as existing systems limit differential braking pressure to prevent yaw moment and skidding, but this limits maximum braking force and increases braking distance.
Innovation Solution
A method that dynamically controls the maximum allowable braking pressure difference between wheels based on vehicle dynamics variables, such as yaw rate deviation and yaw acceleration, to maintain or reduce pressure difference when unstable behavior is detected, allowing for a compromise between stability and braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the maximum allowable braking pressure difference is limited to prevent yaw moment and skidding, then driving stability is improved, but braking distance is lengthened
Solution Approach 1:
The system dynamically adjusts the maximum allowable braking pressure difference based on real-time vehicle dynamics parameters (yaw rate, steering angle, vehicle speed). Instead of using a fixed limit, the control unit continuously adapts the pressure difference threshold to current driving conditions, allowing the system to optimize between stability and braking performance moment by moment
Solution Approach 2:
The invention changes the parameter of maximum allowable braking pressure difference from a constant value to a variable that depends on vehicle dynamics parameters. By deriving this parameter dynamically from measured quantities (yaw rate deviation, steering angle, speed), the system can adapt the braking pressure distribution to achieve both stability and short braking distance under different conditions
2Stability of the object's composition
If the maximum allowable braking pressure difference is maintained to give driver time to countersteer, then vehicle stability is improved, but braking force is reduced
Solution Approach 1:
The system applies partial differential braking pressure when instability is detected, rather than completely limiting the pressure difference. By maintaining the maximum allowable pressure difference at levels that provide stability while still allowing some differential braking, the system achieves a compromise that provides both stabilizing effect and adequate braking force
Solution Approach 2:
The control unit continuously monitors vehicle dynamics parameters and adjusts the braking pressure difference in real-time based on feedback from yaw rate sensors and steering angle sensors. This closed-loop control allows the system to maintain stability while optimizing braking force application according to actual vehicle response
Data Source
AI summary
A method to improve the braking behavior of a vehicle is provided, in which it is not permitted to exceed a maximum allowable braking pressure difference between the braking pressures on the two wheels of one axle, and in which the maximum allowable braking pressure difference between the wheels of one axle is a function of at least one variable describing the vehicle dynamics. When an unstable behavior of the vehicle is recognized, the maximum allowable braking pressure difference between the wheels of the axle is maintained or reduced.