Vehicle Steering Assist Control for Lower Avoidance Steering Force
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Solution Overview
Problem
Existing steering assist devices require higher steering force during avoidance maneuvers to prevent collisions with obstacles, as they encourage drivers to maintain an optimum steering angle through controlled reaction forces.
Innovation Solution
A vehicle steering assist device that includes a steering input member, a steering device, a control torque generating device, and a control unit. The control unit determines the need for avoidance steering and adjusts the control torque to reduce the ratio of return torque change to steering operation amount change, thereby reducing the required steering force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the steering assist device controls the steering reaction force to encourage the driver to steer toward the optimum steering angle, then the driver is guided to maintain proper lane position, but the steering force required for avoidance steering increases when an obstacle is present
Solution Approach 1:
The steering reaction force control is made dynamic by detecting obstacles and changing the control torque characteristics in real-time. When an obstacle is detected, the system transitions from encouraging optimum steering angle to reducing resistance against driver's avoidance steering input, allowing the steering assist force to adapt to different driving situations.
Solution Approach 2:
The control torque parameters are changed based on obstacle detection. The system modifies the relationship between steering operation amount and control torque, specifically reducing the ratio of change amount of control torque to change amount of steering operation amount when avoidance steering is needed, thereby reducing the steering force required for obstacle avoidance.
2Measurement precision
If the control torque is maintained at normal levels during avoidance steering, then the steering precision is maintained, but the driver experiences higher steering effort and reduced maneuverability
Solution Approach 1:
The system performs preliminary detection of obstacles and prepares the steering assist control in advance. When an obstacle is detected, the control unit proactively changes the control torque characteristics before the driver needs to perform avoidance steering, ensuring the steering system is already optimized for easy maneuverability when needed.
Solution Approach 2:
The system continuously monitors the steering operation amount and obstacle position, providing feedback to the control unit. Based on this feedback, the control torque is dynamically adjusted to match the driver's intended maneuver, reducing steering effort while maintaining precision through continuous adaptation to the driver's inputs.
Data Source
AI summary
In a vehicle steering assist device that includes an electric power steering device that generates a control torque that modifies a return torque for urging a steering wheel to a neutral position, a steering assist ECU that controls the control torque, and a surrounding information detecting device (camera sensor, radar sensor) that detects at least information in front of a vehicle, the control torque is controlled such that a ratio of a change amount of the modified return torque to a change amount of a steering operation amount at the start of avoidance steering decreases when an obstacle is detected in front of the vehicle by the surrounding information detecting device and the avoidance steering for the vehicle to avoid collision with the obstacle is determined to be required.