Steering Control Device Torque Offset Strategy
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Solution Overview
Problem
Steering control devices face challenges in providing a consistent and comfortable steering feel for drivers when the host control device intervenes in steering control, leading to discomfort due to varying torque levels when turning the steering wheel forward or backward during automated driving.
Innovation Solution
A steering control device that calculates additional control amounts to offset deviations in the actual angle from the target angle, ensuring a balanced and restricted motor output to maintain a consistent steering feel by summing and restricting control amounts, and adjusting gains for proportional, integral, and differential operations to reduce feedback performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the second control amount is increased to eliminate the deviation of the actual angle from the target angle during driver intervention, then the tracking performance is improved, but the steering torque becomes excessive and hinders the driver's steering operation
Solution Approach 1:
The control amount is segmented into three distinct components: first control amount (based on turning state), second control amount (for adapting actual angle to target angle), and third control amount (for offsetting the second control amount during intervention). This segmentation allows each component to be optimized independently, with the third control amount specifically designed to counterbalance the excessive torque from the second control amount during driver intervention, thereby resolving the contradiction between tracking performance and ease of operation.
Solution Approach 2:
The system dynamically changes the control parameters by calculating the third control amount based on the turning state to offset the second control amount. This parameter adjustment ensures that when the driver intervenes in steering control, the excessive torque generated by the second control amount is counterbalanced, maintaining both accurate angle tracking and smooth steering operation.
2Extent of automation
If the host control device intervenes in steering control, then automated driving functionality is improved, but the steering feel becomes inconsistent and uncomfortable for the driver
Solution Approach 1:
The third control amount is calculated in advance to offset the second control amount before the driver completes their steering intervention. This preliminary anti-action prevents the excessive torque from the second control amount from hindering the driver's steering operation, thereby maintaining consistent and comfortable steering feel during automated driving intervention while preserving automated driving functionality.
3Ease of operation
If the steering control device calculates additional control amounts to maintain consistent steering feel, then driver comfort is improved, but the device complexity increases
Solution Approach 1:
The first control amount (based on turning state), second control amount (for angle adaptation), and third control amount (for offsetting during intervention) are merged into a unified control strategy. This integration allows the system to maintain consistent steering feel during driver intervention while managing complexity through a cohesive control architecture rather than separate independent systems.
Data Source
AI summary
A steering control device includes: a first calculator configured to calculate, according to a turning state, a first control amount for causing a motor to generate an assistance force; a second calculator configured to calculate a second control amount for adapting an actual angle to a target angle that is convertible into a turning angle of a steering wheel and generated when a host control device intervenes in steering control; and a third calculator configured to calculate, according to the turning state, a third control amount for offsetting the second control amount when the host control device intervenes in steering control.