Capacitive Fabric Sensor for Impact Detection
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Solution Overview
Problem
Current impact detection systems for ballistic and non-ballistic impacts on bodies are inadequate, as they either rely on indirect measurements with fragile mesh fabrics or require complex signal processing with peizo electric film sensors, failing to accurately measure impact characteristics like back face velocity and absorption energy.
Innovation Solution
A portable impact detection system incorporating capacitive fabric compression sensors integrated into impact surfaces, which detect changes in electrical characteristics due to impacts and process these into digital data for analysis, including a processing circuit, user interface, storage, and communication capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mesh fabric incorporating fibre optics is used to detect impact penetration, then impact detection capability is provided, but the system becomes very fragile and cannot accurately determine ballistic impact from fabric tears
Solution Approach 1:
The patent replaces the mechanical fibre optic sensing system with a capacitive sensor system that uses electrical field measurements. The capacitive sensors detect impact forces through changes in capacitance values, eliminating the need for physical fibre optics that are prone to breaking from fabric tears while maintaining reliable impact detection capability.
Solution Approach 2:
The patent integrates capacitive sensors directly into the armour fabric structure, creating a composite material system where the sensing elements are embedded within the fabric layers. This integration provides both structural integrity and sensing capability, preventing the fragility issue of separate fibre optic components while maintaining reliable impact detection.
2Reliability
If peizo electric film sensors are used to detect acoustic vibration patterns from impacts, then impact detection capability is provided, but the system requires complex signal processing and filtering to discriminate impact signatures from noise
Solution Approach 1:
The patent replaces piezoelectric acoustic vibration sensors with capacitive force sensors that directly measure impact forces. This substitution eliminates the need for complex acoustic signal processing and filtering, as the capacitive sensors provide direct electrical measurements of impact forces without requiring discrimination from background noise.
Solution Approach 2:
The patent extracts and eliminates the complex signal processing and filtering subsystem from the impact detection system. By using capacitive sensors that provide direct electrical measurements, the system removes the need for the complicated acoustic signature analysis infrastructure, simplifying the overall device while maintaining reliable impact detection.
3Reliability
If peizo film sensors with battery powered analogue or digital circuitry are used, then impact detection is enabled, but the system requires considerable signal processing and filtering infrastructure that must be carried by the user
Solution Approach 1:
The patent extracts and removes the heavy battery-powered analogue and digital circuitry infrastructure from the system. The capacitive sensor system requires minimal electronic components for operation, eliminating the need for substantial power supplies and complex signal processing hardware that would add significant weight to the wearable device.
Solution Approach 2:
The patent replaces the heavy piezoelectric sensor system with battery-powered circuitry with a lightweight capacitive sensing system that uses simple electrical measurements. This substitution dramatically reduces the weight of the detection system while maintaining reliable impact detection functionality through direct capacitance measurements.
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 system provides accurate and reliable detection and measurement of impact characteristics, such as ballistic and non-ballistic impacts, enabling rapid response and improved survivability by providing direct and precise data on impact forces and energies.
Implementation Method 1
at least one fabric compression sensor having an electrical characteristic attached to or integral with said impact surface and adapted to detect an impact event on said body
Implementation Method 2
Other ballistic impact detection systems incorporate peizo electric film sensor elements attached to body armour for example. The peizo film sensors detect acoustic vibration patterns caused by impacts and convert them into a voltage.
Data Source
AI summary
A garment may be used for detecting an impact. The garment may include a capacitive compression sensor attached to the garment having an inner and outer layer of conductive material as well as a compressible non-conductive material between the inner and outer layers. The outer layer of conductive material may include an electrical isolation region. The garment may further include an impact detection device electrically connected to the capacitive compression sensor via a conductor that traverses the electrical isolation region. The impact detection device may include a processing circuit configured to process a change in a capacitance of the capacitive compression sensor into a digital format representative of the impact. The outer layer of conductive material may enclose the inner layer of conductive material.