Steering Control Device Abnormal Speed Torque Adjustment
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Solution Overview
Problem
In steer-by-wire steering systems, erroneous vehicle speed detection due to sensor abnormalities can lead to inappropriate target steering reaction forces, affecting the vehicle's traveling state.
Innovation Solution
A steering control device with a target torque generator that calculates a target torque based on pre-adjustment, first, and second axial forces, adjusting their proportions and limits to prevent abnormal values, and includes a post-adjustment axial force calculator that reduces the contribution of vehicle speed-adjusted forces when the vehicle speed is abnormal, ensuring the target torque remains appropriate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target steering reaction force is calculated using vehicle speed, then the steering performance is optimized, but the system becomes vulnerable to sensor abnormalities causing erroneous values
Solution Approach 1:
The system performs preliminary validation of the vehicle speed signal before using it for target torque calculation. The abnormality determination unit checks whether the detected vehicle speed is within a predetermined valid range, and only allows calculation proceeds when the speed is confirmed normal, preventing erroneous values from affecting steering performance
Solution Approach 2:
The invention introduces an intermediary validation mechanism (abnormality determination unit) between the vehicle speed sensor and the target torque calculation. This intermediary layer filters out abnormal values by comparing them against predetermined ranges, allowing the system to use valid speed data for optimization while blocking erroneous data from causing harmful effects
2Object-affected harmful factors
If the target steering reaction force is calculated without considering vehicle speed, then the system is immune to speed sensor abnormalities, but the steering performance deteriorates
Solution Approach 1:
The system performs preliminary validation of the vehicle speed signal before using it for target torque calculation. The abnormality determination unit checks whether the detected vehicle speed is within a predetermined valid range, and only allows calculation proceeds when the speed is confirmed normal, preventing erroneous values from affecting steering performance
Solution Approach 2:
The invention introduces an intermediary validation mechanism (abnormality determination unit) between the vehicle speed sensor and the target torque calculation. This intermediary layer filters out abnormal values by comparing them against predetermined ranges, allowing the system to use valid speed data for optimization while blocking erroneous data from causing harmful effects
Data Source
AI summary
A steering control device includes a target torque generator configured to generate a target torque which is a target value of the motor torque and a control signal generator configured to generate a control signal for controlling the motor such that the motor torque corresponding to the target torque is generated. The target torque generator includes a pre-adjustment axial force calculator, a first axial force calculator, a second axial force calculator, a post-adjustment axial force calculator, and a target torque calculator. The post-adjustment axial force calculator is configured to set a proportion of a first axial force contributing to a post-adjustment axial force to be smaller when a state of a vehicle speed is abnormal than when the state of the vehicle speed is normal.