Steer-by-Wire Neutral Position Correction During Straight Driving
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Solution Overview
Problem
In steer-by-wire steering systems, deviations in the neutral steering position can occur due to adjustments in the toe angle of the steerable wheel or external forces, leading to improper steering and an unnatural driving experience, especially when driving support controls like lane departure prevention and vehicle stabilization are required.
Innovation Solution
A steer-by-wire steering system with a controller that executes a neutral position deviation elimination process, gradually adjusting the stored neutral position to match the actual neutral position while maintaining straight driving, allowing safety-oriented driving support controls to function even with some deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the neutral steering position is set using target travel line following control, then the neutral steering position can be set with high accuracy, but the control method becomes complicated and cannot be executed before high accuracy is acquired
Solution Approach 1:
The system uses the driver's own straight driving operation to automatically detect and correct the neutral steering position deviation. The driver maintains straight driving while the system autonomously executes the correction process by adjusting the stored neutral steering position based on the detected deviation, eliminating the need for complex external calibration procedures.
Solution Approach 2:
The system continuously monitors the steering angle sensor output during straight driving and compares it with the expected neutral position. When a deviation is detected, the system provides feedback by automatically adjusting the stored neutral steering position to eliminate the deviation, creating a closed-loop correction mechanism that simplifies the overall control process.
2Reliability
If the neutral steering position is not accurately set, then driving support controls cannot be executed, but setting it requires complicated learning processes
Solution Approach 1:
The system enables driving support controls to become available through the driver's own straight driving operation. The neutral steering position is automatically corrected in the background without requiring the driver to perform complex calibration procedures or the system to execute complicated learning processes, thus improving reliability while maintaining simplicity.
Solution Approach 2:
The system performs preliminary correction of the neutral steering position automatically during normal straight driving operations before driving support controls are needed. This preliminary action ensures that the neutral position is accurate and ready for driving support control execution without requiring complex setup procedures at the time of control activation.
3Ease of operation
If the stored neutral position deviates from the actual neutral position, then the wheel is not appropriately steered and the driver feels unnatural, but frequent recalibration disrupts driving
Solution Approach 1:
The system continuously monitors the steering angle during straight driving operations and maintains accurate neutral position calibration through ongoing detection and correction. This continuous action eliminates the need for frequent discrete recalibration events, ensuring steering naturalness while minimizing disruption to the driver's workflow.
Solution Approach 2:
The system implements continuous feedback monitoring of the steering angle sensor during normal driving operations. When neutral position deviation is detected, automatic correction is triggered to restore steering naturalness, eliminating the need for frequent manual recalibration and maintaining ease of operation throughout the vehicle's usage.
Data Source
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AI summary
A steer-by-wire steering system mounted on a vehicle, including: an operation member (10) operable by a driver; a steering actuator (16) having a drive source (38) and configured to steer a wheel (14) by a force of the drive source; a controller (42) configured to control the steering actuator so as to cause the wheel to be steered in accordance with an operation of the operation member, wherein, when a stored neutral position, which is a neutral steering position stored for controlling the steering actuator, deviates from an actual neutral position, which is an actual neutral steering position, the controller executes, in a state in which the operation of the operation member to cause the vehicle to travel straight by the driver of the vehicle is maintained, a neutral position deviation elimination process in which the stored neutral position is brought closer to the actual neutral position.