Electric Motor Torque Vectoring for Understeer Control
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Solution Overview
Problem
Conventional torque vectoring control methods in vehicles result in power loss and limitations in control response speed, precision, and linearity due to mechanical systems, making it difficult to effectively manage handling characteristics, especially in rear-wheel drive and front-wheel drive vehicles.
Innovation Solution
A control method that uses a controller to determine the vehicle's understeer or oversteer state and adjusts motor torque between the front and rear wheels based on the driver's acceleration willingness, allowing for precise control of motor torque distribution without power loss, utilizing characteristics like fast response and linearity of electric motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional torque vectoring control uses brake operation to control understeer or oversteer characteristics, then handling performance is improved, but power loss occurs and power efficiency decreases
Solution Approach 1:
The patent replaces the conventional mechanical brake-based torque vectoring system with an electric motor system. Each wheel is equipped with an independent motor that can directly control wheel torque without using brakes, thereby eliminating power loss associated with brake operation while maintaining or improving handling performance.
Solution Approach 2:
The patent extracts the torque control function from the brake system and assigns it to independent motor units at each wheel. This separation allows the brake system to focus solely on stopping functions while motors handle torque vectoring, eliminating the power loss that occurs when brakes are used for torque control.
2Force
If conventional torque vectoring uses mechanical systems with hydraulic pressure and brake friction, then torque control is achieved, but control response speed, precision, and linearity are limited
Solution Approach 1:
The patent replaces the multi-stage mechanical control system (hydraulic pressure → brake friction → actuation force) with direct electric motor control. This eliminates the mechanical transmission stages that limit response speed, precision, and linearity, allowing for rapid and precise torque adjustment at each wheel.
Solution Approach 2:
The patent divides the vehicle's drive system into four independent motor units, one for each wheel. This segmentation allows each wheel to be controlled independently with high precision and fast response, overcoming the limitations of centralized mechanical control systems that must manage all wheels through a single hydraulic system.
3Power
If power from one engine is distributed to front and rear wheels, then power delivery is achieved, but the power of the four wheels cannot be controlled independently
Solution Approach 1:
The patent segments the power delivery system into four independent motor units, one for each wheel. This allows each wheel to receive and control its own power independently, enabling precise torque vectoring and adaptive power distribution that cannot be achieved with a single engine distributing power through a mechanical transmission system.
Solution Approach 2:
The patent replaces the mechanical power distribution system (single engine → transmission → differential → wheels) with an electric power distribution system where each wheel has its own motor. This substitution enables independent control of each wheel's power output, providing superior adaptability for various driving conditions and handling scenarios.
Data Source
AI summary
A control method of vehicle handling includes determining that a driving state of a vehicle is an understeer state from an electronic stability control, determining a position of an accelerator from an accelerator position sensor in response to determining that the driving state of the vehicle is the understeer state, and controlling a motor torque of a front wheel side of the vehicle to be smaller than a motor torque of a rear wheel side of the vehicle according to the position of the accelerator.