Steer-by-Wire Steering Ratio Adjustment for Feedback Actuator Failure
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Solution Overview
Problem
Conventional steer-by-wire steering systems face challenges in maintaining consistent steering behavior and operational safety when the feedback actuator fails, leading to unintended steering movements and undesirable vehicle responses.
Innovation Solution
The method involves monitoring the operation of the feedback actuator and modifying the steering ratio between the operating unit and the wheel steering angle control element to change the steering characteristic, ensuring a consistent steering behavior even when the feedback actuator transitions to a passive state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the feedback actuator is designed to provide active feedback torque in a steer-by-wire steering system, then the steering feel and driver feedback are improved, but if the feedback actuator fails, unintended steering movements occur leading to undesirable vehicle responses
Solution Approach 1:
The steering ratio is made dynamically adjustable based on the operational state of the feedback actuator. When the feedback actuator is functioning normally, a first steering ratio is used to provide appropriate steering feel. When the feedback actuator fails or transitions to a passive state, the system switches to a second steering ratio that is smaller than the first, thereby compensating for the loss of active feedback torque and preventing unintended steering movements.
Solution Approach 2:
The system changes the steering ratio parameter depending on the operational state of the feedback actuator. By monitoring whether the feedback actuator is in an active state (providing feedback torque) or a passive state (not providing feedback torque), the control system adjusts the steering ratio accordingly to maintain stable steering behavior and prevent harmful steering movements during fault conditions.
2Reliability
If the steering ratio is reduced to compensate for feedback actuator failure, then unintended steering movements are prevented, but the steering characteristic changes may affect normal steering performance
Solution Approach 1:
The steering ratio is dynamically adjusted based on the operational state of the feedback actuator. When the feedback actuator is functioning normally, a first steering ratio is used to provide appropriate steering feel. When the feedback actuator fails or transitions to a passive state, the system switches to a second steering ratio that is smaller than the first, thereby compensating for the loss of active feedback torque and preventing unintended steering movements.
Solution Approach 2:
The system continuously monitors the operational state of the feedback actuator and adjusts the steering ratio accordingly. By detecting whether the feedback actuator is in an active state (providing feedback torque) or a passive state (not providing feedback torque), the control system adapts the steering characteristic to maintain stability and prevent harmful steering movements during fault conditions.
Data Source
AI summary
The disclosure relates to a method for operating a steering system of a vehicle, in particular a motor vehicle. The steering system is designed as a steer-by-wire steering system and includes an operating unit, which has at least one steering handle and at least one feedback actuator that interacts with the steering handle, and at least one wheel steering angle control element, which is operatively connected to the operating unit, for changing the steering angle of at least one vehicle wheel. An operation of the feedback actuator is monitored using a monitoring function, and in at least one operating state in which a disturbance and/or a failure of the feedback actuator is ascertained using the monitoring function, a steering characteristic of the steering system is modified. A steering ratio between the operating unit and the wheel steering angle control element is modified in order to change the steering characteristic.