Miniaturized Wireless Piezoelectric Accelerometer with Hybrid Shielding
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Solution Overview
Problem
Current wireless piezoelectric accelerometers are bulky, interfere with machine operations, have unstable mounting, and limited dynamic frequency range due to their large size and high aspect ratio, and suffer from electromagnetic interference and restricted operation range due to design constraints.
Innovation Solution
A miniaturized wireless piezoelectric accelerometer with a metallic shielding chamber and a non-metallic portion for RF transmission, incorporating a piezoelectric MEMS bending-mode or shear-mode sensor, signal processing, and wireless modules in a compact casing, which minimizes interference and resonances, and includes a power supply module with batteries for extended operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wireless piezoelectric accelerometers use bulky piezoelectric ceramic materials as the sensing element, then the sensing capability is achieved, but the overall package becomes bulky resulting in substantial interference to machine operation and inability to monitor small machines
Solution Approach 1:
The patent changes the material parameter from bulky piezoelectric ceramic materials to miniaturized piezoelectric MEMS sensors, transforming the sensing element from a bulk ceramic component to a micro-scale device that maintains piezoelectric functionality while dramatically reducing volume and mass
Solution Approach 2:
The patent replaces the traditional mechanical ceramic piezoelectric element with a micro-electromechanical system (MEMS)-based piezoelectric sensor, substituting the bulk mechanical sensing approach with a miniaturized version that integrates sensing and signal processing functions
2Shape
If wireless piezoelectric accelerometers have high aspect ratio and protrude out of the machine, then the sensing element can be accommodated, but the structure becomes unstable with highly elevated weight centres and hard to steadily mount
Solution Approach 1:
The patent changes the dimensional configuration from a high aspect ratio protruding structure to a low aspect ratio compact package, transitioning from a vertically extended geometry to a horizontally compact form that maintains sensing capability while improving mounting stability
Solution Approach 2:
The patent addresses the elevated weight center issue by redistributing the mass of the accelerometer components to lower the center of gravity within the compact package, counteracting the instability caused by protruding structures
3Object-affected harmful factors
If wireless piezoelectric accelerometers are packaged within a metal casing, then electromagnetic interference protection is provided, but noise in the accelerometer is significantly higher due to RF transmission requirements
Solution Approach 1:
The patent segments the casing into metallic and non-metallic portions, creating a hybrid structure where the metallic portion provides EMI shielding for the sensing element while the non-metallic portion allows RF transmission, thereby resolving the conflict between protection and communication
Solution Approach 2:
The non-metallic portion of the casing acts as an intermediary that allows RF signals to pass through while the metallic portion maintains EMI shielding, mediating between the conflicting requirements of electromagnetic protection and wireless communication
4Volume of moving object
If wireless piezoelectric accelerometers use small batteries for power supply, then the device can be miniaturized, but the operation range is limited due to energy constraints and regulatory restrictions on RF transmission power
Solution Approach 1:
The patent implements continuous monitoring capability through an always-listening receiver architecture that maintains constant communication readiness, ensuring uninterrupted data transmission and extended operational duration without requiring large power reserves
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 solution provides a compact, stable, and efficient wireless accelerometer system with reduced electromagnetic interference, extended operation range, and improved dynamic frequency range, enabling effective vibration monitoring of small machines without disrupting their operation.
Implementation Method 1
a piezoelectric sensing element configured to sense mechanical acceleration and produce an electrical charge signal in response of the sensed mechanical acceleration
Data Source
AI summary
Wireless piezoelectric accelerometers and systems are provided. A wireless piezoelectric accelerometer may comprise a piezoelectric sensing element configured to sense mechanical acceleration and produce an electrical charge signal in response of the sensed mechanical acceleration, a signal processing module (SPM) configured to convert the electrical charge signal into a voltage signal, and process and digitize the voltage signal, and a wireless module configured to modulate and transmit the digitized voltage signal as wireless signals. The piezoelectric sensing element, the SPM and the wireless module are packaged in a casing. The casing comprises a metallic shielding chamber configured to enclose the piezoelectric sensing element. The casing further comprises a non-metallic portion located in relative to the wireless module to allow transmission of the wireless signals. Corresponding wireless piezoelectric accelerometer systems are also provided.