Steer-by-Wire Steering Lock Control Using Feedback Counter-Torque
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Solution Overview
Problem
Steer-by-wire steering systems lack an effective steering lock mechanism that provides a comfortable and secure parking experience, as the steering wheel moves freely between locking positions, making it uncomfortable for drivers to use the steering wheel as a handle when entering or exiting the vehicle.
Innovation Solution
A method for controlling steering locking in steer-by-wire systems using a feedback actuator with an electric motor connected to the steering shaft, which applies counter-torque to the steering shaft when the ignition is off, engaging the locking element with the latching element at discrete positions, mimicking the feel of electromechanical systems and ensuring the steering wheel is locked, even when power is switched off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steering lock unit with latching element and locking element is used to secure the parked vehicle, then the steering shaft is locked at discrete locking positions, but the steering wheel moves freely between locking positions making it uncomfortable for drivers
Solution Approach 1:
The feedback actuator serves as an intermediary between the driver's steering input and the steering shaft. It generates counter-torque to simulate mechanical feedback, filling the gap between the discrete mechanical locking positions and providing continuous resistance to steering wheel movement, thereby making the steering wheel comfortable to move even when not at a locking position.
Solution Approach 2:
The patent replaces the traditional mechanical continuous resistance mechanism with an electric feedback actuator that uses electromagnetic force to generate counter-torque. This substitution allows for precise control of the steering feel and enables the system to provide appropriate resistance whether the steering wheel is at a locking position or between locking positions.
2Ease of operation
If the feedback actuator applies counter-torque to simulate steering feel, then the steering wheel becomes difficult to move, but excessive torque may prevent proper locking engagement
Solution Approach 1:
The feedback actuator dynamically adjusts its counter-torque output based on the steering shaft's position and movement. The control unit monitors the steering shaft position and modulates the actuator's torque to provide appropriate resistance during normal operation while reducing or eliminating torque near locking positions to ensure smooth and reliable locking engagement.
Solution Approach 2:
The system uses feedback from position sensors to continuously monitor the steering shaft position and adjust the feedback actuator's counter-torque accordingly. This feedback mechanism ensures that the actuator provides appropriate resistance during steering operations while automatically reducing torque when approaching locking positions, enabling reliable locking engagement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enhances the steering lock mechanism by making the steering wheel difficult to turn until locked, providing a secure and comfortable experience for drivers, similar to conventional systems, by applying counter-torque based on the distance to the next locking position and maintaining feedback actuator activity until the driver is secure inside the vehicle.
Implementation Method 1
a feedback actuator with an electric motor (9) having a motor shaft connected to the steering shaft (6) to be able to transmit a torque
Implementation Method 2
The locking element (12) is spring-loaded in such a way that the locking element (12) can be moved into the locking position against the action of the spring element (11)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method for controlling steering locking of a steer-by-wire steering system (1) of a motor vehicle, the steer-by-wire steering system (1) comprising a feedback actuator (4) to simulate a steering feel to a steering device (5), wherein said feedback actuator (4) has an electric motor (9) with a motor shaft connected to a steering shaft (6) to be able to transmit a torque, and a steering lock unit (10) with a latching element (11) connected to the steering shaft (6) in a torsion-resistant manner and a locking element (12) that is configured to engage with the latching element (11) at discrete locking positions (L1,L2,L3) to block a rotation of the steering shaft (6), wherein the method comprises the following steps: - If the ignition is switched-off and a movement of the steering device (5) is detected, determining the position of the steering shaft (6) and the distance between the locking element (11) and the next locking position (L1,L2,L3) of the latching element (12) in direction of the movement of the steering device (5); - If the distance is greater than a predefined value, transmitting a counter-torque (TFBA) to the steering shaft (6) by the feedback-actuator (4) with opposite direction to the movement of the steering device (6) until the locking position (L1,L2,L3) reaches the locking element (12) and the locking element (12) can engage with the latching element (11).