Steer-by-Wire Feedback Torque Control for Failure Signaling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Steer-by-wire steering systems in motor vehicles face challenges in providing feedback to drivers of system failures or degradation without risking further degradation or failure, particularly when one component fails, leading to potential overheating issues.
Innovation Solution
The method involves increasing the feedback torque provided by the feedback actuator in case of detected failures, with the option to switch off the failing component and maintain higher torque until the vehicle reaches a safe location, using redundant power packs without additional components, and gradually reducing torque to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If feedback torque is increased to signal system restriction to the driver, then feedback effectiveness is improved, but system degradation accelerates over time
Solution Approach 1:
The feedback torque is made dynamically adjustable based on system state. The control unit modifies the feedback torque magnitude according to detected failures or restrictions, allowing the system to adapt torque levels to current operational conditions rather than using fixed torque values
Solution Approach 2:
The feedback torque parameter is changed based on detected system states. When a failure or restriction is detected, the control unit adjusts the feedback torque parameter to provide appropriate feedback to the driver while considering the degraded system state, thereby balancing feedback effectiveness with system protection
2Loss of information
If feedback torque is increased to signal failure to the driver, then failure detection is improved, but thermal overload risk increases
Solution Approach 1:
The feedback torque application is made dynamic and conditional. The control unit continuously monitors system state and only increases feedback torque when specific failure conditions are detected, rather than maintaining continuously high torque levels, thereby reducing overall thermal stress on the system
Solution Approach 2:
The system replaces continuous mechanical torque application with controlled, conditional torque application based on electronic detection and control logic. The control unit uses electronic monitoring to determine when feedback torque should be applied, substituting intelligent control for continuous mechanical stress
Data Source
AI summary
A method to control a steer-by-wire steering system of a road vehicle, the steer-by-wire steering system including a feedback actuator to apply a feedback torque to a steering wheel and a road wheel actuator to turn steerable road wheels with two redundant power packs each, the method including, if a failure in the road wheel actuator is detected, increasing the feedback torque provided by the feedback actuator to a value higher than a calculated feedback torque, and if a failure in one power pack of the feedback actuator is detected, increasing the feedback torque provided by a functioning power pack of the feedback actuator to a value higher than the calculated feedback torque.