Vehicle Steering Torque Feedback for Grip Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle steering devices fail to promptly notify drivers of tire grip force loss due to decreased road surface friction, leading to delayed emergency avoidance operations.
Innovation Solution
A vehicle steering device that generates a target steering torque based on the difference between the real self-aligning torque and the physical quantity of tire slipping, using a predetermined proportionality coefficient to inform the driver of tire grip force loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If target steering torque is controlled to follow real steering torque to avoid influence of road surface state, then steering stability is improved, but driver awareness of tire grip force loss is delayed
Solution Approach 1:
The patent introduces a feedback mechanism that compares the torque signal (based on steering angle and vehicle speed) with the self-aligning torque (physical quantity from tire slipping). When their difference exceeds a threshold, the system generates a warning signal to notify the driver of tire grip force loss. This feedback loop allows the system to maintain stable steering control while simultaneously providing timely information to the driver about road surface conditions.
2Ease of operation
If target steering torque follows real steering torque on low-friction roads, then steering control is smoothed, but emergency avoidance response time is increased
Solution Approach 1:
The patent introduces an intermediary warning signal mechanism that mediates between the smoothed steering control and the driver's need for timely information. The warning signal acts as an intermediary notification system that informs the driver of tire grip force loss without interfering with the smooth steering control, enabling the driver to take appropriate emergency actions while maintaining comfortable steering operation.
3Loss of information
If target steering torque is adjusted to reflect tire slipping conditions, then driver feedback of grip force loss is improved, but calculation complexity increases
Solution Approach 1:
The patent extracts only the essential comparison between torque signal and self-aligning torque to detect tire grip force loss. Instead of implementing complex analysis of all steering parameters, the system focuses on extracting and comparing these two key quantities. When their difference exceeds a predetermined threshold, a warning is generated. This extraction approach provides effective driver feedback while keeping the calculation complexity minimal.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vehicle steering device configured to assist and control a steering system of a vehicle by driving and controlling a motor configured to assist steering force. A target steering torque generation unit 200 configured to generate target steering torque Tref of the motor is included. The target steering torque generation unit 200 generates the target steering torque Tref in accordance with the difference value of a torque signal Tref_a0 in accordance with a steering angle and a vehicle speed from a value obtained by multiplying a physical quantity generated through tire slipping by a predetermined proportionality coefficient.