Vehicle Torque Vectoring for Transient Handling
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Solution Overview
Problem
Heavier battery-powered vehicles exhibit sluggish transient handling due to increased weight, leading to a longer response time when torque is applied, which can result in instability if response time is simply accelerated.
Innovation Solution
A method and system for controlling vehicles by integrating actuator dynamics with vehicle dynamics to determine optimal torque and rear wheel angle commands using a cost function that balances agility and stability, employing a linear quadratic regulator and feedforward/feedback algorithms to minimize the objective function, thereby improving transient handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery-powered vehicles are made heavier to increase power, then power is improved, but transient handling becomes sluggish
Solution Approach 1:
The system dynamically changes control parameters (torque distribution, steering angles) based on vehicle state to optimize transient response. The controller adjusts torque vectoring and active rear steering parameters in real-time to compensate for the heavy mass, enabling faster response without modifying the vehicle's physical weight.
2Speed
If response time is accelerated to improve transient handling, then transient response speed is improved, but vehicle stability deteriorates
Solution Approach 1:
The system employs feedback control by continuously monitoring vehicle state (lateral acceleration, yaw rate) and adjusting torque vectoring and steering commands accordingly. This closed-loop control enables rapid response while maintaining stability through real-time correction of vehicle dynamics.
Solution Approach 2:
The control system dynamically adapts torque distribution and steering angles based on current vehicle conditions. The active rear steering and torque vectoring mechanisms adjust in real-time to achieve optimal balance between response speed and stability during transient maneuvers.
Data Source
AI summary
A method of controlling a vehicle includes obtaining a linear representation of a vehicle dynamics model that includes actuator dynamics u integrated with vehicle dynamics x. The actuator dynamics u include a road wheel angle at rear wheels δr and a torque Mz. The method also includes obtaining an objective function based on a function of the vehicle dynamics x and the actuator dynamics u and formulating a cost function to minimize the objective function. The actuator dynamics u including the torque Mz are determined for a next time sample based on minimizing the objective function. The vehicle is controlled to implement the torque Mz.