Vehicle Drift Control Using Yaw Moment and Wheel Torque Vectoring
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Solution Overview
Problem
Existing vehicle systems, particularly those with all-wheel drive (AWD) and limited-slip differentials (LSD), struggle to facilitate optimal drift performance due to insufficient torque distribution between left and right wheels, leading to challenges in entering, maintaining, and transitioning drift behavior, especially in electric vehicles with motor-based drive systems.
Innovation Solution
A control method using a controller to determine the vehicle's driving situation and generate a drift index, adjusting target yaw moments and wheel torques based on driver inputs and vehicle states to enhance drift entry, maintenance, and transition, incorporating acceleration, steering, and yaw damping assistance controls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an all-wheel drive (AWD) system is provided, then vehicle stability and traction performance are improved, but the slip angle of rear wheels is reduced making drift driving difficult
Solution Approach 1:
The control method applies different torque distribution strategies to different wheels based on their functional requirements. Front wheels receive torque for stability and traction, while rear wheels receive controlled torque reduction to enable drift. This local differentiation of torque quality allows the AWD system to simultaneously maintain stability benefits while enabling drift capability.
Solution Approach 2:
The system dynamically adjusts torque distribution between front and rear wheels based on detected driving conditions and drift state. The controller continuously monitors vehicle state and modifies torque allocation in real-time, transitioning from stable AWD operation to drift-enabling torque reduction, thereby providing both stability during normal driving and adaptability for drift mode.
2Adaptability or versatility
If a limited-slip differential (LSD) is used, then torque distribution between left and right wheels is improved, but the system complexity increases
Solution Approach 1:
The patent replaces the mechanical LSD system with an electronic control-based torque vectoring system. Instead of using mechanical components to physically distribute torque, the system uses electronic sensors and controllers to calculate and command optimal torque distribution to each wheel. This substitution reduces mechanical complexity while maintaining or enhancing torque distribution capability.
Solution Approach 2:
The control system dynamically changes torque parameters distributed to each wheel based on real-time vehicle state and drift conditions. By electronically adjusting torque magnitude and direction to individual wheels, the system achieves adaptive torque distribution without the mechanical complexity of traditional LSD components, thereby improving versatility while managing system complexity.
3Stability of the object's composition
If torque is distributed to front wheels in AWD mode, then straightness and stability are improved, but the ability to enter and maintain drift is reduced
Solution Approach 1:
The control system implements periodic modulation of front wheel torque during drift operation. Rather than maintaining constant torque distribution, the system periodically adjusts front wheel torque levels to help initiate drift and then modulates them to maintain drift state. This periodic torque action enables drift entry and maintenance while preserving the stability benefits of AWD during transitions.
Solution Approach 2:
The system applies different torque qualities to front versus rear wheels. Front wheels receive controlled torque that maintains some stability while allowing drift, whereas rear wheels receive reduced torque to enable slip. This local differentiation of torque application allows the vehicle to simultaneously achieve reasonable straightness control and drift capability.
Data Source
AI summary
A method of controlling drift of a vehicle in which the vehicle more easily enters, maintains, releases, and transitions drift behavior, includes determining, by a controller, whether a current driving situation of the vehicle is a drift entry situation or a release situation based on vehicle driving information, and generating a drift index configured to indicate a current degree of drift from a determination result, determining, by the controller, a target yaw moment for left and right speed control depending on a driving situation or a braking situation of the vehicle and target yaw moments for drift assistance control depending on a driver input and a vehicle state in the drift entry situation, based on the vehicle driving information, and generating and outputting, by the controller, a target torque of a motor configured to drive each wheel of the vehicle based on the determined target yaw moments.