Steering Assist Torque Control for Smooth Mode Transition
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Solution Overview
Problem
Existing driver assistance systems cause discomfort to drivers and passengers when switching from manual to automatic steering mode due to sudden changes in steering wheel rotation and vehicle behavior, as the steering speed is not adequately controlled when the driver is holding the wheel.
Innovation Solution
A vehicle driver assistance system that includes a steering assist torque generation device and a control device capable of determining whether the driver is holding the steering wheel, adjusting the rate of change in automatic steering torque to reduce discomfort by limiting the steering speed change when the driver is holding the wheel, and ensuring effective steering angle control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the maximum value of steering speed of automatic steering is limited when the driver is holding the steering wheel, then the possibility of driver and passenger discomfort is reduced, but the steering speed becomes excessively limited and the steering angle cannot be quickly controlled to the desired value
Solution Approach 1:
The patent applies dynamics by making the steering speed limit value variable rather than fixed. The control device dynamically adjusts the limit value based on whether the driver is holding the steering wheel or not. When the driver is not holding the wheel, a higher limit value is applied for quick response. When the driver is holding the wheel, a lower limit value is applied to reduce discomfort. This dynamic adjustment resolves the contradiction between comfort and speed responsiveness.
Solution Approach 2:
The patent changes the parameter of steering speed limit value based on driver input state. By detecting whether the driver is holding the steering wheel, the system changes the parameter (limit value) to appropriately balance comfort and responsiveness. This parameter change allows the system to adapt to different driving situations and resolve the contradiction between limiting steering speed for comfort and maintaining high steering speed for effective control.
2Productivity
If a large limit value is set for steering speed, then the steering angle can be quickly controlled to the desired value, but the driver and passenger may feel discomfort due to large rotational speed and vehicle behavior changes
Solution Approach 1:
The system dynamically adjusts the limit value based on real-time detection of driver steering wheel holding state. When the driver is not holding the wheel, the system applies a larger limit value for fast steering angle control. When the driver is holding the wheel, the system applies a smaller limit value to reduce discomfort from sudden vehicle behavior changes. This dynamic adaptation resolves the contradiction between productivity and comfort.
Solution Approach 2:
The patent implements feedback by detecting the driver's steering wheel holding state and using this information to adjust the steering speed limit value. The control device continuously monitors driver input and adjusts the limit value accordingly, creating a closed-loop system that balances steering angle control speed with driver and passenger comfort based on actual driving conditions.
3Object-affected harmful factors
If a small limit value is set for steering speed, then driver and passenger discomfort is reduced, but the steering angle cannot be quickly controlled to the desired steering angle and driver assistance is not provided effectively
Solution Approach 1:
The patent resolves this contradiction by making the limit value dynamic rather than fixed. The system detects whether the driver is holding the steering wheel and adjusts the limit value accordingly. When the driver is not holding the wheel, a larger limit value is applied to reduce the time needed to control the steering angle. When the driver is holding the wheel, a smaller limit value is applied to reduce discomfort. This dynamic adjustment eliminates the need to choose between comfort and responsiveness.
Solution Approach 2:
The system changes the parameter (limit value) based on the driver's steering wheel holding state. By detecting driver input, the system appropriately changes the parameter to balance comfort and steering angle control time. This parameter change strategy allows the system to provide effective driver assistance when needed while minimizing discomfort when the driver is actively steering.
Data Source
AI summary
A vehicle driver assistance system includes: a steering assist torque generation device configured to generate steering assist torque; a control device configured to control the steering assist torque generation device; and a switch configured to switch a steering mode between a manual steering mode and an automatic steering mode. The manual steering mode is a mode in which steered wheels are steered as a driver operates a steering wheel. The automatic steering mode is a mode in which the steered wheels are steered by the steering assist torque generated by the steering assist torque generation device.