Electric Power Steering Torque Correction for Driver Intention
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Solution Overview
Problem
Existing driving support devices for vehicles struggle to accurately determine and respond to a driver's intention to deviate from a target course without unnecessarily correcting the course, leading to delayed lane changes and unsatisfied driver intentions.
Innovation Solution
A driving support device that includes a steering angle detection system, a steering torque detection system, and an electric power steering control system, which calculates a target steering angle and adjusts the driving support torque based on the driver's steering intention by analyzing the difference between the actual steering angle and the target angle, using products of the steering angle and torque to determine the driver's intention and correct the torque accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the predetermined reference value for steering operation is set to a large value to prevent unnecessary target course correction, then the target course stability is improved, but the lane change responsiveness deteriorates
Solution Approach 1:
The system dynamically changes the reference value threshold based on the product of steering angle and steering torque. When the product exceeds the threshold, the system determines driver intention to change lanes and adjusts the reference steering angle accordingly. This parameter-based dynamic adjustment resolves the contradiction by enabling responsive lane changes only when genuine driver intention is detected, while maintaining stability during normal driving.
Solution Approach 2:
The system continuously monitors the product of steering angle and steering torque, comparing it against the reference value threshold. This feedback mechanism enables the system to detect when the driver intends to change lanes and responds by adjusting the reference steering angle. The feedback loop ensures that lane changes are initiated only when the driver's intention is clearly indicated, resolving the contradiction between stability and responsiveness.
2Measurement precision
If the driving support torque actively returns the steering angle to the target steering angle, then the target course tracking precision is improved, but the driver intention recognition accuracy deteriorates
Solution Approach 1:
The system performs preliminary detection of driver intention by monitoring the product of steering angle and steering torque before executing course correction. When the product exceeds the reference value threshold, the system identifies this as genuine driver intention to deviate from the target course. This preliminary action prevents the driving support torque from incorrectly counteracting legitimate lane change intentions, resolving the contradiction between tracking precision and intention recognition.
Solution Approach 2:
The system changes the control parameter (reference steering angle) based on the detected driver intention. When the steering angle and steering torque product exceeds the threshold, the reference steering angle is adjusted to allow the vehicle to deviate from the original target course. This parameter adaptation enables the system to maintain tracking precision for genuine target course following while recognizing and accommodating driver-initiated lane changes.
Data Source
AI summary
A driving support device may be configured to calculate a target steering angle for allowing a vehicle to travel along a target course; set, as a reference steering angle, a steering angle when a difference between the steering angle and the target steering angle is small; calculate an indication value indicating intention of a driver's steering operation as a sum of a first product of a corrected steering angle and a steering torque, a second product of a derivative of the corrected steering angle and the steering torque, and a third product of the corrected steering angle and a derivative of the steering torque; and correct the target steering angle based on the indication value so that a target driving support torque is corrected in accordance with the intention of the driver's steering operation.