Steering Wheel Torque Signal Frequency Analysis for Hand Detection
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Solution Overview
Problem
Conventional detection systems for determining if a vehicle operator's hands are positioned on a hand wheel require additional sensors, increasing cost and complexity.
Innovation Solution
A method and control system that generate frequency content from hand wheel torque signals to estimate whether hands are on the wheel, using a combination of low and high frequency content to produce a hands on wheel estimate signal, which is used to operate vehicle systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors are placed on the hand wheel to detect hand position, then the accuracy of hand-on-wheel detection is improved, but the cost and complexity of the steering system increase
Solution Approach 1:
The existing hand wheel torque sensor performs dual functions: measuring torque for steering control and detecting hand-on-wheel status through frequency analysis. The sensor serves itself by analyzing its own output signal characteristics rather than requiring separate detection sensors.
Solution Approach 2:
The system detects hand-on-wheel status by analyzing changes in frequency parameters of the torque signal. When hands are on the wheel, characteristic frequency components appear in the torque signal, which are detected through spectral analysis rather than by additional physical sensors.
2Reliability
If additional sensors are placed on the hand wheel to detect hand position, then the reliability of hand detection is improved, but the manufacturing cost increases
Solution Approach 1:
The torque sensor is designed to perform multiple functions: primary steering torque measurement and secondary hand-on-wheel detection. This multi-functionality eliminates the need for additional dedicated detection sensors, reducing component count and manufacturing cost while maintaining detection reliability.
Solution Approach 2:
The torque sensor system analyzes its own operational characteristics to detect hand presence. By monitoring frequency content of its own output signal, the system achieves reliable detection without requiring separate sensing components, thereby reducing manufacturing expenses.
Data Source
AI summary
A method for determining whether hands of an operator of a vehicle are positioned on a hand wheel of the vehicle is provided. The method generates a first frequency content below a first frequency from a hand wheel torque signal. The method generates a second frequency content above a second frequency from the first frequency content of the hand wheel torque signal. The method generates a hands on wheel (HOW) estimate signal based on the first frequency content and the second frequency content by determining a first contribution of the first frequency content to the HOW estimate signal, determining a second contribution of the second frequency content to the HOW estimate signal, and combining the first contribution and the second contribution to generate the HOW estimate signal. The method causes a system in a vehicle to operate based on the HOW estimate signal.