Brake Locking Pressure Estimation for Multi-Axle Vehicle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional brake systems in multi-axle vehicles face challenges in maintaining steerability during dynamic axle-load transfers, as the normal force change affects the coefficient of friction, leading to potential wheel locking and instability.
Innovation Solution
A method to estimate the locking pressure in the wheel brake device by determining it at a first point in time during the maximum coefficient of friction and using this information to extrapolate the locking pressure at a subsequent point in time, adjusting the brake pressure level to prevent wheel locking, utilizing wheel speed and ride-height sensors to monitor normal force changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If brake pressure is increased to improve braking effectiveness, then braking performance is improved, but wheel locking occurs causing loss of steerability
Solution Approach 1:
The system performs preliminary determination of locking pressure at a first point in time during the ABS pressure reduction phase, before the wheel actually locks. This advance knowledge allows the control system to predict and prevent wheel locking by adjusting brake pressure proactively, maintaining steerability while preserving braking effectiveness.
Solution Approach 2:
The system dynamically adapts brake pressure control by continuously monitoring wheel normal force changes during axle-load transfer and adjusting the locking pressure estimate accordingly. This dynamic adjustment allows the brake pressure to be optimized in real-time to prevent wheel locking while maintaining maximum braking effectiveness.
2Ease of operation
If brake pressure is reduced to prevent wheel locking, then steerability is maintained, but braking effectiveness decreases
Solution Approach 1:
The system uses feedback from wheel speed sensors and ride-height sensors to continuously monitor wheel normal force and slip conditions. This feedback loop allows the control system to determine the optimal brake pressure that maintains steerability while maximizing braking effectiveness, adjusting pressure dynamically based on actual wheel loading conditions.
Solution Approach 2:
The system changes the brake pressure parameter dynamically based on the determined locking pressure and current wheel normal force. By adjusting brake pressure to match the determined locking pressure threshold, the system maintains steerability while achieving maximum braking effectiveness without unnecessary pressure reduction.
3Adaptability or versatility
If locking pressure is determined dynamically during axle-load transfer, then adaptability to changing conditions is improved, but system complexity increases
Solution Approach 1:
The system determines locking pressure at a specific preliminary point in time during the ABS pressure reduction phase, rather than continuously. This approach provides adaptability to axle-load transfer while avoiding the complexity of continuous real-time determination, using discrete measurement points to capture essential dynamics.
Solution Approach 2:
The system uses a simplified model that copies the relationship between wheel normal force and locking pressure determined at the first point in time. This model allows the system to adapt to changing axle-load conditions without requiring complex real-time calculations, reducing control system complexity while maintaining adaptability.
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
Enables adaptive brake pressure control to prevent wheel locking, ensuring steerability and optimizing braking performance by accurately estimating locking pressure during dynamic axle-load transfers, reducing the risk of instability and allowing for high braking effectiveness.
Implementation Method 1
The longitudinal slip may be determined from the wheel speed, which may be detected via a wheel speed sensor
Implementation Method 2
The variables required for determining the locking pressure during the axle-load transfer may be detected sensorially. It is possible for example to ascertain the wheel normal force on the vehicle wheel with the aid of a ride-height sensor, which measures body movements
Implementation Method 3
The level of the transferable brake force depends on the current coefficient of friction between the wheel and the ground
Data Source
AI summary
In a method for estimating the locking pressure in the brake system of a multi-axle vehicle during a dynamic axle-load transfer, the locking pressure is ascertained during the axle-load transfer and the wheel normal force is ascertained at two points in time during the axle-load transfer and the locking pressure is ascertained therefrom at the later point in time.