Active Steering Fallback Mode for Roll Control Faults
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Solution Overview
Problem
Active roll control systems in motor vehicles can malfunction, leading to undesirable roll and yaw responses that compromise vehicle dynamics, comfort, and safety, especially during cornering maneuvers.
Innovation Solution
A method that operates an active steering system in a fallback mode when a malfunction in the active roll control system is detected, adjusting the steering response to reduce lateral acceleration and prevent oversteer by superposing a corrective angle on the driver's steering input, thereby maintaining dynamic stability and alerting the driver through acoustic and visual signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the active roll control system operates in normal mode, then the vehicle provides optimal roll control and steering response, but the system may malfunction and cause undesirable roll and yaw responses
Solution Approach 1:
The steering system dynamically switches between normal operating mode and fallback operating mode based on the functional status of the active roll control system. In normal mode, the system provides optimal steering response. When a malfunction is detected, it automatically transitions to fallback mode with modified steering characteristics to maintain stability, thus adapting the system behavior to current operational conditions without requiring permanent complexity
Solution Approach 2:
The system prepares a fallback steering mode in advance that can be activated when the active roll control system malfunctions. This pre-prepared alternative steering characteristics (with reduced lateral acceleration and dampened yaw response) acts as a cushion against the potential harmful effects of system failure, ensuring continuous safe operation without requiring immediate complex diagnostic or repair actions
2Reliability
If the active roll control system malfunctions, then vehicle stability is compromised, but switching to fallback mode reduces lateral acceleration and prevents oversteer
Solution Approach 1:
When the active roll control system malfunctions, the fallback steering mode converts the potentially harmful situation (system failure causing instability) into a beneficial outcome by automatically modifying steering characteristics to reduce lateral acceleration and prevent oversteer. The malfunction itself triggers a protective response that uses the altered steering behavior to maintain vehicle control and safety
Solution Approach 2:
The system continuously monitors the operational status of the active roll control system and provides feedback to the steering control. When a malfunction is detected, this feedback triggers the transition to fallback mode, creating a closed-loop control system that automatically adjusts steering characteristics based on real-time system conditions to maintain stability
Data Source
AI summary
A method for operating a motor vehicle having an active roll control and an active steering system designed to map a steering-wheel setting angle predetermined by a driver of the motor vehicle in accordance with a predetermined steer response onto a steer angle of the motor vehicle. The method includes operating the active steering system in a normal operating mode having a normal steer response and upon determining an active roll control fault operating the active steering system in a fallback operating mode in accordance with an fallback steer response, the fallback steer response different from the normal steer response.