Steering Torque Transition for Smooth Manual Control
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Solution Overview
Problem
Existing vehicle steering systems with closed-loop electronic control experience a jolting reduction in steering torque when automatic steering transitions to manual control, leading to an unexpected change in the vehicle's curvature trajectory, which can be unsettling for the driver.
Innovation Solution
A method where the vehicle operates in an automatic phase with calculated torque, senses driver intervention, and maintains or compensates torque during an intervention phase until a defined threshold is exceeded, ensuring smooth transition to manual control by gradually reducing automatic torque, providing haptic feedback and preventing sudden changes in steering torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If automatic steering intervention is ended immediately when driver intervention is detected, then the steering control transfers quickly to manual mode, but the steering torque decreases suddenly causing a jolting sensation and unexpected trajectory change
Solution Approach 1:
The system performs preliminary action by gradually reducing the automatic steering torque before complete transfer to manual mode. The control unit decreases the automatic steering torque in predefined steps over a specified time period, preparing the steering system for smooth transition before the driver fully takes over control.
Solution Approach 2:
The system applies dynamics by making the steering torque reduction adaptive and time-dependent. The automatic steering torque is reduced dynamically over a specified time period rather than abruptly, creating a smooth transition profile that adapts to the driver's intervention while maintaining operational smoothness.
2Ease of operation
If automatic steering torque is reduced gradually to prevent jolting, then the transition to manual control becomes smooth, but the transfer of steering control takes longer time
Solution Approach 1:
The system applies partial action by reducing the automatic steering torque in predefined steps rather than completely eliminating it at once. This gradual reduction in steps allows the transition to proceed smoothly while limiting the total time required, balancing smoothness with acceptable transfer duration.
Solution Approach 2:
The system maintains continuity of useful action by keeping the automatic steering torque active during the transition period, gradually reducing it rather than switching it off abruptly. This continuous torque application ensures smooth transition while the process is optimized to complete within an acceptable time frame.
3Stability of the object's composition
If the steering actuator compensates for manual torque during driver intervention, then the vehicle maintains the automatically set trajectory, but the driver experiences reduced haptic feedback about steering status
Solution Approach 1:
The system changes parameters by adjusting the automatic steering torque in predefined steps rather than maintaining it constant. This parameter change approach allows the trajectory to remain relatively stable while providing the driver with progressive haptic feedback through the changing torque levels, informing the driver of the transition process.
Data Source
AI summary
A method for steering a vehicle, wherein forces for steering wheels are generated by a steering torque. The steering torque is applied by a mechanical steering system and/or a steering actuator. The method includes in the automatic phase: automatic steering of the vehicle, where a control unit calculates an automatic torque and actuates the steering actuator so that the steering torque corresponds to the automatic torque. During the engagement phase when a manual torque applied to the steering wheel by the driver is detected, the method includes maintaining the calculated automatic torque as a steering torque by ignoring or compensating the manual torque until the manual torque has exceeded a defined threshold torque greater than zero. During a transfer phase, the method includes reducing the automatic torque after exceeding the threshold torque, wherein the steering torque corresponds to the sum of the manual torque and automatic torque.