Steering and Torque Vectoring for Delay-Aware Emergency Path Control
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Solution Overview
Problem
Advanced driving assist systems (ADAS) face challenges in implementing effective emergency motion control for vehicles, particularly in scenarios requiring precise lateral movement to avoid obstacles, as existing technologies struggle to optimally combine steering and torque vectoring controls while considering actuator delays and vehicle limits.
Innovation Solution
A method and apparatus that identify a desired path for an ego vehicle, determining the application of steering and torque vectoring controls based on actuator delays and vehicle limits to create lateral movement, using processing devices to apply these controls and manage weights for optimal path tracking, thereby enhancing emergency maneuver performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steering control and torque vectoring control are applied to create lateral movement for emergency avoidance, then the vehicle can follow the desired path and avoid obstacles, but actuator delays cause unstable vehicle motion and reduce control precision
Solution Approach 1:
The controller predicts future vehicle states and calculates control commands in advance to compensate for actuator delays. By performing preliminary calculations of the required steering and torque vectoring commands based on predicted future states, the system ensures that the actual actuator actions occur at the optimal moments, maintaining path tracking precision despite delays in the mechanical response of the steering and drive actuators.
Solution Approach 2:
The controller continuously monitors actual vehicle states (lateral position, yaw rate, lateral acceleration) and compares them with desired states to calculate correction commands. This closed-loop feedback mechanism adjusts the steering and torque vectoring commands in real-time to compensate for actuator delays and maintain stable vehicle motion during emergency avoidance maneuvers, ensuring the vehicle follows the desired path accurately.
2Speed
If aggressive steering control is applied to achieve rapid lateral movement, then the vehicle can respond quickly to obstacles, but vehicle stability deteriorates and tire limits are exceeded
Solution Approach 1:
The controller merges steering control and torque vectoring control into a coordinated system that achieves rapid lateral response while maintaining stability. By combining the quick directional response of steering with the stable lateral movement capability of torque vectoring (which applies differential torque to wheels), the system achieves fast lateral acceleration without exceeding tire friction limits or causing vehicle instability, as torque vectoring provides controlled force application through the tire-road interface.
Solution Approach 2:
The controller dynamically adjusts control parameters (steering angle, torque distribution to individual wheels) based on current vehicle state and desired path. By changing these parameters optimally in real-time - applying larger steering angles when needed while simultaneously adjusting torque vectoring to maintain lateral acceleration within tire adhesion limits - the system achieves rapid lateral response while preserving vehicle stability and avoiding tire saturation.
3Stability of the object's composition
If torque vectoring control is used to provide lateral acceleration, then the vehicle can achieve smooth path following, but actuator delays reduce the effectiveness of emergency maneuvers
Solution Approach 1:
The controller calculates torque vectoring commands in advance based on predicted future vehicle states, compensating for actuator delays. By performing preliminary calculations and issuing commands that account for the delayed mechanical response of the drive actuators, the system ensures that torque vectoring begins at the optimal moment to provide lateral acceleration, reducing the effective response time loss and maintaining emergency maneuver effectiveness while preserving motion stability.
Data Source
AI summary
A method includes identifying a desired path for an ego vehicle. The method also includes determining how to apply steering control and torque vectoring control to cause the ego vehicle to follow the desired path. The determination is based on actuator delays associated with the steering control and the torque vectoring control and one or more limits of the ego vehicle. The method further includes applying at least one of the steering control and the torque vectoring control to create lateral movement of the ego vehicle during travel. Determining how to apply the steering control and the torque vectoring control may include using a state-space model that incorporates first-order time delays associated with the steering control and the torque vectoring control and using a linear quadratic regulator to determine how to control the ego vehicle based on the state-space model and the one or more limits of the ego vehicle.