Capacitive Sensor for Vehicle Entrapment Detection
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Solution Overview
Problem
Current vehicle safety systems lack effective methods to detect both conductive and non-conductive objects, particularly in the vicinity of closing vehicle parts, which can lead to entrapment hazards, especially for children or pets.
Innovation Solution
The integration of capacitive sensors mounted on movable panels and fascia panels within vehicle structures, which change capacitance in response to the presence of objects, allowing for real-time detection and prevention of closure when an object is detected, combined with a controller to manage the movement of vehicle parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional contact-based switches or non-contact optical sensors are used, then the detection mechanism is simple or cost-effective, but they cannot detect both conductive and non-conductive objects effectively
Solution Approach 1:
The capacitive sensor is designed to perform multiple detection functions - it can detect both conductive objects (through capacitance coupling) and non-conductive objects (through dielectric constant changes), replacing the need for separate sensor types and enabling a single sensor system to handle diverse detection requirements
2Reliability
If optical sensors are used for non-contact detection, then entrapment prevention is improved, but they cannot detect non-conductive objects effectively
Solution Approach 1:
The sensor utilizes changes in electrical parameters (capacitance and dielectric constant) to detect objects. Conductive objects change the capacitance coupling between sensor plates, while non-conductive objects alter the dielectric constant of the medium between plates, enabling detection across different object types through parameter-based detection
3Device complexity
If contact-based switches are used, then the detection mechanism is simple, but they require direct contact which delays response time
Solution Approach 1:
The mechanical contact-based switch system is replaced with a capacitive sensing system that detects objects through electrical field coupling. This substitution eliminates the need for physical contact while maintaining detection simplicity, enabling faster response times as the sensor can detect objects before they make contact with moving vehicle parts
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 enables the detection of both conductive and non-conductive objects, preventing entrapment by halting or reversing the movement of vehicle parts, thereby enhancing safety by ensuring objects can safely pass or be cleared before closure.
Implementation Method 1
The sensor capacitively couples to an electrically conductive object proximal to the closure of the vehicle body such that capacitance of the sensor changes
Data Source
AI summary
A bus includes a vehicle body, a plurality of capacitive sensors mounted along a perimeter of the vehicle body, wherein one of the capacitive sensors capacitively couples to an electrically conductive object proximal to the portion of the vehicle body such that the capacitance of the one of the capacitive sensors changes, and a controller coupled to the capacitive sensors, the controller being configured to alert an operator of the bus when the object is coupled to the at least one capacitive sensor.