Torque Vectoring Controller Yaw Rate Feedback
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Solution Overview
Problem
Existing torque vectoring mechanisms can exacerbate vehicle stability issues by overloading the lateral force capacity of rear or front axles, leading to worsened oversteer or understeer conditions when excessive torque is applied.
Innovation Solution
A method and system that control torque distribution between left and right wheels based on yaw rate, steering angle, and estimated lateral force capacities, adjusting torque control values to prevent overloading and maintain stability, using a controller to determine and apply torque control values to the torque vectoring mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque vectoring mechanism applies excessive torque to counteract understeer or oversteer, then vehicle stability is improved, but lateral force capacity of the axle saturates and stability deteriorates
Solution Approach 1:
The controller continuously monitors wheel speeds, vehicle yaw rate, and steering angle to calculate the actual yaw rate and compare it with the reference yaw rate. Based on this feedback and the determined lateral force capacities, the controller dynamically adjusts the torque control value to counteract understeer or oversteer conditions while preventing lateral force saturation, thus maintaining vehicle stability without exceeding the axle's lateral force capacity.
Solution Approach 2:
The system dynamically determines lateral force capacities of the wheels based on operating conditions such as wheel speed, yaw rate, and steering angle. The torque control value is continuously adjusted by changing parameters including the yaw rate error, lateral force capacities, and torque distribution ratios, allowing the system to optimize torque application while avoiding lateral force saturation across varying driving conditions.
2Reliability
If torque vectoring mechanism increases torque on outer rear wheel to counteract understeer, then understeer condition is improved, but lateral force capacity of rear axle decreases and oversteer may be aggravated
Solution Approach 1:
The controller calculates the torque control value by considering the yaw rate error, the lateral force capacities of both wheels, and the current operating conditions. This dynamic parameter adjustment ensures that torque is applied to counteract understeer while maintaining sufficient lateral force capacity to prevent oversteer, adapting the torque distribution to the specific driving situation.
Solution Approach 2:
The system uses feedback from wheel speed sensors, yaw rate sensors, and steering angle sensors to continuously monitor vehicle state. This feedback allows the controller to adjust torque distribution in real-time, ensuring that counteracting understeer does not push the rear axle into lateral force saturation that would cause oversteer, thereby maintaining overall vehicle stability.
3Reliability
If torque vectoring mechanism increases torque on inner rear wheel to counteract oversteer, then oversteer condition is improved, but lateral force capacity of rear axle decreases and oversteer condition may worsen
Solution Approach 1:
The controller dynamically adjusts the torque control value based on the yaw rate error (comparing actual yaw rate with reference yaw rate), the lateral force capacities of the wheels, and current operating conditions. This ensures that torque application to counteract oversteer is optimized to prevent lateral force saturation, avoiding the worsening of oversteer condition while maintaining vehicle stability.
Solution Approach 2:
The system continuously monitors vehicle yaw rate, wheel speeds, and steering angle to provide feedback to the controller. This feedback mechanism allows the controller to adjust torque distribution to counteract oversteer while preventing excessive torque application that would saturate the lateral force capacity and aggravate the oversteer condition, thereby maintaining vehicle stability.
Data Source
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AI summary
A method of controlling a torque vectoring mechanism that distributes torque between a left and a right wheel of a vehicle includes determining a reference yaw rate of the vehicle based on a speed and a steering angle of the vehicle and determining a first torque control value based on a yaw rate of the vehicle and the reference yaw rate. The method also includes: (i) determining longitudinal slip value for each of the left and right wheels, (ii) determining a combined slip value based on the longitudinal slip values, and (iii) determining a second torque control value based on the combined slip value. Further, the method includes determining a final torque control value based on the first torque control value and the second torque control value and distributing torque between the left and right wheels based on the final torque control value. A torque vectoring system is also provided.