Autonomous Emergency Braking Control System for Vehicle Stability
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Solution Overview
Problem
Autonomous emergency braking systems in vehicles may cause vehicles to skid off the road when applied in curves due to insufficient lateral tire force, especially under non-ideal road conditions such as wet or icy surfaces, as they assume ideal conditions like straight roads and high deceleration rates.
Innovation Solution
A control system that estimates friction and predicts lateral tire force based on road curvature, adapting the brake strategy to initiate braking earlier and with lower force in curves, using friction-estimating braking and adjusting for road conditions to prevent skidding, and providing assistance for steering maneuvers if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If standard autonomous emergency braking is applied with high deceleration rate (≥4 m/s²) in curves, then braking effectiveness is improved, but vehicle stability deteriorates causing skidding off the road
Solution Approach 1:
The brake strategy is dynamically adapted based on real-time road curvature information and predicted lateral tire force requirements. The system transitions from fixed deceleration rates to variable braking profiles that adjust according to road geometry and vehicle state, preventing skidding while maintaining braking effectiveness.
Solution Approach 2:
The system changes the braking parameters (deceleration rate, brake force distribution) based on road curvature and friction conditions. By modifying these parameters according to predicted lateral force requirements, the system resolves the contradiction between achieving high deceleration and maintaining vehicle stability in curves.
2Reliability
If autonomous emergency braking assumes ideal road conditions, then braking performance is improved, but adaptability to non-ideal conditions deteriorates
Solution Approach 1:
The system implements feedback mechanisms by continuously monitoring road curvature and estimating road friction conditions. This feedback loop allows the brake strategy to adapt to actual road conditions rather than assuming ideal scenarios, improving reliability across diverse operating environments.
Solution Approach 2:
The system performs preliminary estimation of road friction and prediction of lateral tire force requirements before applying brakes. This preliminary action allows the system to pre-adjust braking parameters based on predicted conditions, ensuring reliable performance whether roads are wet, icy, or dry.
3Length of moving object
If lateral tire force is reduced during emergency braking, then braking distance is improved, but vehicle control in curves deteriorates
Solution Approach 1:
The system dynamically changes braking parameters based on predicted lateral force requirements. By adjusting the longitudinal brake force profile according to road curvature and friction estimates, the system achieves optimal braking distance while preserving sufficient lateral tire force for curve negotiation.
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
Reduces the risk of accidents by maintaining vehicle stability and accuracy in stopping distance under non-ideal conditions, while minimizing fuel consumption and brake wear, and providing accurate warnings and assistance for drivers.
Implementation Method 1
a braking force is predicted which can be generated in cases where avoidance steering is carried out by the driver, in order to avoid an obstacle which has been detected, and an actual braking force actually applied to a longitudinal direction of the vehicle is limited in accordance with a braking force which can be applied in the longitudinal direction of the vehicle and which is calculated based on the lateral force thus predicted and on a friction of the vehicle with respect to a road surface
Data Source
AI summary
A control system is provided for a vehicle including an autonomous emergency braking system, characterized in that the control system includes: a brake control arrangement adapted to apply a friction-estimating braking when the autonomous emergency braking system has initiated a possible intervention; a brake force capacity estimation arrangement adapted to estimate the brake force capacity of the vehicle as a function of longitudinal wheel slip based on the applied friction-estimating braking; a road information arrangement adapted to obtain information about road curvature ahead of the vehicle; a lateral tyre force prediction arrangement adapted to predict lateral tyre force needed during autonomous emergency braking based on the obtained information about road curvature; and a brake strategy adaptation arrangement configured to adapt the brake strategy of the autonomous emergency braking system based on the estimated brake force capacity and the predicted lateral tyre force needed.