AWD Driving Force Distribution for Stability and Ride Comfort
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Solution Overview
Problem
Existing all-wheel drive systems face issues with driving stability and ride comfort when adjusting front-wheel and rear-wheel driving force distribution ratios, leading to oversteer, understeer, or excessive wheel slip during vehicle maneuvers.
Innovation Solution
A driving force adjusting device and method that includes an input unit for user-selected distribution ratios, a driving force determination unit to adjust distribution based on driving information and conditions like friction coefficient and stability indices, and a control unit to redistribute driving force between front and rear wheels to maintain stability and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the user-selected driving force distribution ratio is maintained during vehicle turning, then the user's selected ride comfort is preserved, but driving stability deteriorates due to oversteer, understeer, or excessive wheel slip
Solution Approach 1:
The driving force determination unit dynamically adjusts the driving force distribution ratio based on real-time driving information (vehicle speed, steering angle, yaw rate) while preserving the user-selected distribution ratio as the base. The system transitions from a static user-selected ratio to a dynamic adjusted ratio that responds to driving conditions, resolving the contradiction between maintaining user comfort and ensuring driving stability.
Solution Approach 2:
The receiving unit continuously acquires driving information including vehicle speed, steering angle, and yaw rate to monitor the actual driving state. This feedback loop enables the driving force determination unit to detect when stability issues arise and adjust the driving force distribution accordingly, allowing the system to maintain user comfort while preventing instability through real-time monitoring and adjustment.
2Reliability
If the driving force distribution ratio is adjusted for driving stability, then oversteer and understeer are reduced, but the user cannot feel the ride comfort selected by the user
Solution Approach 1:
The driving force determination unit applies only the necessary adjustment to the driving force distribution ratio rather than completely overriding the user selection. By making partial adjustments based on driving information, the system maintains most of the user-selected comfort characteristics while introducing just enough modification to prevent stability issues, thus balancing both requirements.
3Adaptability or versatility
If clutch control is used to distribute driving force in all-wheel drive systems, then driving force can be distributed between front and rear wheels, but maximum driving force cannot be applied to driving wheels not directly connected to the power source
Solution Approach 1:
The system determines the optimal driving force distribution ratio in advance based on driving information before actual power delivery occurs. By calculating the required distribution ratio beforehand considering vehicle dynamics and driving conditions, the clutch control system can prepare the appropriate torque distribution, ensuring maximum power is available to the driving wheels that need it most without losing the adaptability to distribute force as needed.
Data Source
AI summary
A driving force adjusting device includes an input unit configured for receiving an input of a selection distribution ratio, which is a ratio of driving force generation of front wheels and rear wheels selected by a user, a receiving unit configured for receiving driving information of a vehicle, a driving force determination unit configured for determining a driving force distribution ratio, which is a driving force generation ratio of the front wheels and the rear wheels, and determining driving force of the front wheels and the rear wheels using the driving force distribution ratio, and a driving control unit configured for controlling a driving unit generating driving force of the vehicle based on the driving force determined by the driving force determination unit.