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 that includes a controller to execute a neutral position deviation elimination process, adjusting the stored neutral position closer to the actual neutral position while maintaining straight driving, using a combination of steering and reaction force actuators to ensure accurate steering without sudden changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the neutral steering position is adjusted to compensate for deviations, then the steering accuracy is improved, but the system complexity increases due to additional correction mechanisms
Solution Approach 1:
The system continuously monitors the actual neutral steering position and compares it with the stored neutral position. When a deviation is detected, the controller automatically executes a correction process that adjusts the stored neutral position to match the actual position, eliminating the need for complex manual calibration mechanisms while maintaining high steering accuracy
Solution Approach 2:
The neutral position correction is performed automatically by the system itself without requiring external intervention or complex calibration equipment. The controller uses the steering angle sensor data to self-correct the stored neutral position, making the system self-maintaining and reducing overall complexity
2Measurement precision
If the stored neutral position is gradually adjusted during straight driving, then the neutral position deviation is eliminated, but the time required for correction increases
Solution Approach 1:
The correction process is designed to be dynamic and adaptive, adjusting the stored neutral position incrementally during straight driving conditions. The system monitors driving state and only performs corrections when the vehicle is traveling straight, making the correction process efficient and context-dependent rather than requiring dedicated calibration time
Solution Approach 2:
The system performs neutral position correction during normal straight driving operations, utilizing existing driving conditions rather than requiring separate calibration sessions. This approach integrates the correction process into regular vehicle operation, eliminating dedicated correction time while maintaining accuracy
3Productivity
If driving support controls are executed during neutral position correction, then the system remains operational, but control accuracy may be compromised due to position deviations
Solution Approach 1:
The system selectively applies neutral position correction only when specific conditions are met (vehicle traveling straight), while allowing driving support controls to operate continuously. This partial correction approach maintains system availability for safety-critical functions while progressively improving accuracy without compromising overall control performance
Data Source
AI summary
A steer-by-wire steering system mounted on a vehicle, including: an operation member operable by a driver; a steering actuator having a drive source and configured to steer a wheel by a force of the drive source; a controller 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.