Steering Wheel Optical Finger Detection for Zero-Contact Monitoring
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Solution Overview
Problem
Existing systems for detecting the presence and number of fingers on a steering wheel are not precise, as they cannot differentiate between hands and other body parts, nor can they accurately determine when the steering wheel is not being held, leading to unreliable information for driver monitoring and assisted driving systems.
Innovation Solution
A method using optical sensors with infrared diodes and photodiodes arranged on the steering wheel rim to capture light intensity under natural and artificial illumination, providing real-time composite information on the number of hands and fingers, including the 'zero fingers' condition, and a system that discriminates between hands and other objects, ensuring accurate detection regardless of lighting conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque sensors are used to detect driver input on the steering wheel, then the system can measure the force applied, but it cannot distinguish whether the torque comes from hands or other body parts like knees
Solution Approach 1:
The steering wheel rim is divided into multiple sensing zones with individual optical sensors positioned at different locations. Each sensor independently detects finger presence in its specific zone, allowing the system to segment the detection task and identify which specific fingers are contacting the wheel, thereby distinguishing hand presence from other body parts.
Solution Approach 2:
The patent replaces mechanical torque sensors with optical detection systems using infrared transmitting diodes and receiving photodiodes. This substitution enables non-contact detection of finger presence through light absorption changes, providing more precise information about which fingers are present without relying on force measurement that cannot distinguish body parts.
2Reliability
If pressure sensors are arranged inside the steering wheel rim to detect finger contact, then the system can detect strong pressure, but it cannot accurately determine when the steering wheel is not being held at all
Solution Approach 1:
The optical sensors continuously monitor the steering wheel rim surface, and the system uses the natural absence of light absorption signals to detect when no fingers are present. The sensors serve themselves by detecting the baseline light transmission condition and identifying deviations from this baseline, enabling reliable detection of both contact and non-contact states.
Solution Approach 2:
The system detects changes in light absorption properties when fingers contact the steering wheel rim. Fingers absorb infrared light, creating a detectable change in the optical signal. This optical property change provides reliable distinction between finger presence and absence, enabling accurate detection of the zero-contact state.
3Measurement precision
If optical sensors with infrared diodes are used to detect finger presence, then the system can provide precise information about number of fingers, but the system complexity increases
Solution Approach 1:
The patent combines the infrared transmitting diode and receiving photodiode into integrated sensor units positioned around the steering wheel rim. Multiple sensors work in parallel, each detecting finger presence in its zone. The system merges the detection function across multiple sensors to achieve accurate finger counting while managing complexity through functional integration and parallel operation.
Solution Approach 2:
The optical sensor system serves multiple functions: detecting finger presence, counting the number of fingers, determining their positions on the rim, and identifying when the steering wheel is not being held. This multi-functionality reduces the need for separate detection systems for each parameter, managing overall system complexity while providing comprehensive information.
4Measurement precision
If sensors are permanently positioned on the steering wheel rim, then the system can detect finger contact, but accessories or bands fixed to the rim could permanently occlude sensors and trick the monitoring system
Solution Approach 1:
The system dynamically evaluates sensor signals to detect patterns consistent with actual finger movement versus static occlusion. Fingers naturally move and change position during steering, creating dynamic detection patterns. The system uses this dynamic behavior to distinguish transient finger contact from permanent occlusion by accessories, maintaining reliability against fraud attempts.
Solution Approach 2:
The monitoring system continuously receives feedback from multiple optical sensors and analyzes the pattern of detections. When a sensor is permanently occluded, the feedback pattern differs from normal finger contact patterns. The system uses this feedback analysis to identify and flag potential fraud conditions, maintaining system reliability despite the presence of accessories.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides precise and reliable information to assisted driving or monitoring systems, enabling better driver monitoring and preventing potential misuse by ensuring accurate detection of finger presence and steering wheel engagement, even in varying lighting conditions.
Implementation Method 1
capturing the light intensity received by the receiving diodes under natural illumination, the transmitting diodes not being active
Implementation Method 2
outfitted with infrared transmitting diodes and receiving photodiodes
Data Source
AI summary
Disclosed is a system for a motor vehicle, including a steering wheel (2) connected to the steering system of the vehicle, the steering wheel including a plurality of optical sensors (7) arranged on the rim (25) of the steering wheel and designed to detect the presence of at least one finger (5) of at least one hand of the driver near or in contact with the rim of the steering wheel, by way of which the system is able to determine the number of fingers near or in contact with the rim of the steering wheel as well as their respective positions on the rim. Also disclosed is a method associated with the device.