Steer-by-Wire Emergency Steering with Torque Vectoring Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steer-by-wire steering systems fail to accurately reproduce the original driving behavior during emergency steering mode without mechanical aids, impairing vehicle performance and functionality.
Innovation Solution
A method for controlling a steer-by-wire steering system that utilizes a torque vectoring system to distribute drive and braking torques to the front and rear wheels, enabling precise steering control by determining corrective steering angles and torques to maintain the original vehicle behavior, even in the event of a fault.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical auxiliary systems are provided to enable emergency steering, then the steering function is maintained during faults, but the installation space increases and the advantages of steer-by-wire are impaired
Solution Approach 1:
The patent replaces mechanical auxiliary steering systems with an electrical torque vectoring system. The control device uses the torque vectoring system to generate corrective yaw moments that compensate for steering failures, eliminating the need for mechanical backup systems and their associated space requirements.
Solution Approach 2:
The control device acts as an intermediary between the steering system and torque vectoring system. It detects steering failures and coordinates the torque vectoring system's response to maintain vehicle controllability, providing a bridge between the failed steering function and the compensatory torque distribution.
2Reliability
If mechanical auxiliary systems are used for emergency steering, then steering functionality is maintained, but the mounting complexity and variants increase
Solution Approach 1:
The torque vectoring system, originally designed for performance enhancement, is made multi-functional by enabling it to perform both its primary torque distribution function and emergency steering compensation. This eliminates the need for separate emergency steering mechanisms and reduces overall system complexity.
Solution Approach 2:
The patent substitutes mechanical emergency steering systems with an electronically controlled torque vectoring approach, reducing mounting complexity and enabling easier adaptation to different vehicle configurations including left- and right-hand drive variants.
3Reliability
If mechanical auxiliary systems are provided for emergency steering, then steering function is maintained, but crash performance is impaired
Solution Approach 1:
The patent replaces mechanical auxiliary steering systems with an electrical torque vectoring system that has no moving mechanical parts in the steering path. This eliminates potential failure points and mechanical interference during crash events, improving crash performance while maintaining steering functionality.
4Measurement precision
If torque vectoring system is used to reproduce original vehicle behavior, then steering precision is improved, but the control complexity increases
Solution Approach 1:
The control device continuously monitors steering wheel position, vehicle state, and torque vectoring system performance, using this feedback to dynamically adjust torque distribution and maintain accurate reproduction of original steering behavior despite the increased control complexity.
Solution Approach 2:
The control device pre-calculates the torque distribution required to achieve desired steering responses and prepares compensation strategies in advance, reducing the real-time control complexity while maintaining high steering precision during emergency operations.
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling a steer-by-wire steering system for a motor vehicle (1) with steerable front and rear wheels in an emergency steering mode, comprising the following steps: - checking the steering system (2) for the presence of a fault condition, - performing the emergency steering mode to maintain the original vehicle behavior when a fault condition is detected, wherein the following steps are performed in the emergency steering mode: - determining the target lateral acceleration based on the actual steering wheel position and the actual vehicle speed, - determining the yaw moment and from this a general wheel steering angle δg for the original vehicle behavior,where the general wheel steering angle δg is given by δg = δf − δr δg - general wheel steering angle δf - front wheel steering angle δr - rear wheel steering angle - Determining a correction front wheel steering angle Δδf and a correction rear wheel steering angle Δδr and - Determining the drive torques and/or braking torques for the front wheels (FL, FR) and the rear wheels (RL, RR), which are distributed accordingly by the torque vectoring system.