Vehicle Impact Avoidance Using Real-Time Tire-Road Friction
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Solution Overview
Problem
Existing vehicle control systems fail to effectively utilize the coefficient of friction between road and tire to avoid impacts with objects, particularly in situations where road friction is inadequate, leading to potential accidents.
Innovation Solution
A method and system that detects objects along the vehicle's path, determines the coefficient of friction in real-time, and commands appropriate control actions such as braking or steering to avoid impacts, using a controller and sensor system to estimate friction and plan evasive maneuvers based on friction thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle control system determines the coefficient of friction in real-time and uses it to select between braking and steering actions, then the reliability of impact avoidance is improved, but the device complexity increases due to additional sensors and processing requirements
Solution Approach 1:
The controller is designed to perform multiple functions: detecting objects, determining coefficient of friction, calculating time to impact, and selecting appropriate control actions (braking or steering). This multi-functionality consolidates what could be separate systems into a single controller, improving reliability while managing complexity through integration rather than multiplication of components.
Solution Approach 2:
The system continuously monitors the coefficient of friction between the road and tires and uses this feedback to dynamically adjust the control action selection. This real-time feedback mechanism ensures that the control system adapts to changing road conditions, improving the reliability of impact avoidance by selecting appropriate actions (braking on low-friction surfaces, steering on high-friction surfaces).
2Measurement precision
If the system applies braking load to determine the coefficient of friction, then the measurement precision of friction is improved, but the loss of time for the avoidance maneuver increases
Solution Approach 1:
The system applies a partial braking load specifically for the purpose of determining the coefficient of friction, rather than applying full braking immediately. This partial action is sufficient to generate the necessary friction data for accurate measurement while consuming minimal time. The controller uses this friction information to then select the optimal avoidance maneuver, effectively balancing the time spent on measurement with the need for rapid response.
Solution Approach 2:
The system performs the friction measurement action (applying braking load) in advance of the final avoidance maneuver selection. By determining the coefficient of friction before committing to a specific avoidance action, the system ensures that the subsequent braking or steering decision is based on accurate friction data, improving measurement precision without significantly delaying the overall response time.
3Productivity
If the vehicle steers to avoid the object on high-friction roads, then the productivity of the avoidance maneuver is improved, but the stability of the vehicle deteriorates due to lateral forces
Solution Approach 1:
The system changes the control parameter (selecting between braking and steering) based on the measured coefficient of friction. On high-friction roads, the system parameter changes to allow steering maneuvers, which are more efficient for avoidance. On low-friction roads, the parameter changes to prioritize braking actions, which maintain vehicle stability. This dynamic parameter selection based on friction conditions optimizes both avoidance efficiency and vehicle stability.
Solution Approach 2:
The control system dynamically adjusts the avoidance strategy based on real-time friction conditions. Rather than using a fixed approach, the system adapts its behavior: selecting steering maneuvers when friction is high (improving avoidance efficiency) and braking maneuvers when friction is low (maintaining stability). This dynamic adaptation allows the system to optimize the trade-off between avoidance productivity and vehicle stability according to current road conditions.
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
Enhances vehicle safety by enabling precise avoidance of objects through friction-aware control, optimizing braking and steering actions to mitigate collisions, especially in low-friction conditions.
Implementation Method 1
A braking system is in communication with the wheel actuators and configured to apply a braking force to at least one wheel of the vehicle
Implementation Method 2
The coefficient of friction between the road surface and the vehicle tires
Data Source
AI summary
A method controlling a vehicle includes detecting that an object is along a path of the vehicle and within a predetermined distance from the vehicle, in response to detecting the object that is along the path of the vehicle and within the predetermined distance from the vehicle, determining, in real time, a coefficient of friction between a road and a tire of the vehicle, and in respond to determining the coefficient of friction between the road and the tire of the vehicle, commanding the vehicle to perform a control action.