Leaky Coaxial Cable Proximity Sensor for Steering Wheel
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Solution Overview
Problem
Current capacitive sensors for detecting a driver's hand on a steering wheel are sensitive to environmental conditions and fail when the driver is wearing gloves, and they have complex electronics with a large footprint, making them unsuitable for vehicle integration.
Innovation Solution
A proximity sensor using a leaky coaxial cable embedded in the steering wheel, which detects the presence and location of a driver's hand by measuring reflections of near-field electromagnetic waves, regardless of glove usage, with a simplified design that can be integrated into the steering wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitive sensor system is used to detect driver's hand, then the hand detection function is achieved, but the sensitivity varies with environmental conditions and glove usage
Solution Approach 1:
The patent replaces the capacitive sensing system with an electromagnetic wave-based leaky coaxial cable system. Instead of measuring capacitance changes affected by environmental factors, the system uses electromagnetic wave reflection characteristics that are insensitive to gloves and environmental conditions, achieving reliable hand detection across all scenarios
Solution Approach 2:
The patent changes the detection parameter from capacitance (which varies with environmental conditions) to electromagnetic wave reflection characteristics (which remain stable). By measuring the reflection coefficient and phase changes of electromagnetic waves along the leaky coaxial cable, the system achieves consistent performance regardless of temperature, humidity, or glove usage
2Reliability
If a capacitive sensor system is used, then hand detection is possible, but the electronics complexity and footprint are large
Solution Approach 1:
The patent replaces complex capacitive sensing electronics with a simpler electromagnetic wave transmission system. The leaky coaxial cable itself serves as both the transmission medium and the sensing element, eliminating the need for complex capacitive measurement circuits and reducing overall system complexity
Solution Approach 2:
The leaky coaxial cable performs multiple functions simultaneously: it serves as an electromagnetic wave transmission line, a sensing element for hand detection, and can be integrated into the steering wheel structure. This multi-functionality reduces the number of separate components needed, simplifying the overall system
3Reliability
If a capacitive sensor system is used, then hand presence detection is achieved, but the sensor footprint is large making vehicle integration difficult
Solution Approach 1:
The patent divides the sensing function into multiple segments along the leaky coaxial cable length. Different sections of the cable can detect hand presence at different positions on the steering wheel, allowing distributed sensing with minimal footprint. The cable can be routed throughout the steering wheel structure to provide comprehensive coverage
Solution Approach 2:
The leaky coaxial cable can be embedded within the steering wheel structure itself, nesting the sensing element within the existing mechanical components. This integration approach minimizes additional footprint while enabling hand detection across the steering wheel surface
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
The sensor effectively detects the presence and location of a driver's hand with improved robustness and reduced complexity, enabling reliable operation in various conditions and compact integration within the steering wheel.
Implementation Method 1
detects the presence and location of a driver's hand by measuring reflections of near-field electromagnetic waves
Implementation Method 2
The proximity sensor can include a transceiver unit and a leaky coaxial cable operably coupled to the transceiver unit
Data Source
AI summary
Example proximity sensors are described. The proximity sensor can include a transceiver unit, and a leaky coaxial cable operably coupled to the transceiver unit. The proximity sensor described herein can be used with a steering wheel. For example, the leaky coaxial cable can be embedded in the steering wheel.