Steer-by-Wire Stability Control with Disturbance Decoupling
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Solution Overview
Problem
Conventional steer-by-wire steering systems cause driver discomfort due to the application of steering reaction forces that encourage turning to suppress disturbances, leading to variations in steering reaction force that discomfort the driver.
Innovation Solution
A stability control device that controls the turning amount of a turning unit based on a steer-by-wire turning amount and a suppression turning amount to counteract yaw moments generated by disturbances, with a camera detecting yaw moments based on the angle formed by a white line and the vehicle's travel direction, and sets a dead zone where the suppression turning amount is zero when the detected yaw moment is below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If steering reaction force component is applied to suppress disturbance, then vehicle stability is improved, but driver comfort deteriorates
Solution Approach 1:
The patent segments the steering system into two independent control loops: one for disturbance suppression (controlling turning wheel to counteract yaw moment) and one for steering reaction force (controlling steering wheel to provide feedback to driver). This separation allows each loop to operate independently without interfering with the other, resolving the contradiction between vehicle stability and driver comfort.
Solution Approach 2:
The patent introduces an intermediary control mechanism where the steering reaction force is generated based on the steering wheel angle rather than being directly coupled to the disturbance suppression torque. This intermediary approach allows the system to provide stable steering feedback to the driver while the disturbance suppression operates separately through the turning wheel, eliminating the discomfort caused by direct coupling.
2Stability of the object's composition
If steering reaction force is changed to suppress disturbance, then disturbance suppression effectiveness is improved, but steering feel consistency deteriorates
Solution Approach 1:
The patent divides the control system into separate modules: the disturbance suppression module adjusts the turning wheel angle to counteract detected yaw moments, while the steering reaction force module independently controls the steering wheel position based on steering angle feedback. This segmentation ensures that disturbance suppression actions do not directly alter the steering reaction force, maintaining consistent steering feel while effectively suppressing disturbances.
Data Source
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AI summary
The turning angle of the left and right front wheels (5L, 5R) is controlled based on an SBW command turning angle corresponding to the steering angle of a steering wheel (6) mechanically uncoupled from the left and right front wheels (5L, 5R) and a disturbance suppression command turning angle to suppress the yaw angle generated in the vehicle by disturbance, and the steering reaction force to be applied to a column shaft (7) is controlled based on the steering angle of the steering wheel (6).