Influence of the Flexure Position and a Thick Gold Film on the Performance of Beam-Mass Structures
TL;DR: In this article, a miniaturized piezoresistive accelerometer with high magnitude of prime-axis signal and a very low crossaxis signal was realized. Numerical simulations are performed to investi...
Abstract: In the present work, we realize a miniaturized piezoresistive accelerometer with high magnitude of prime-axis signal and a very low cross-axis signal. Numerical simulations are performed to investi...
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01 Jan 2021
TL;DR: Wearable devices are no longer simple passive systems providing the user limited information, but rather they are multifunctional, powerful, and intelligent devices which make use of complex sensing and signal processing elements along with cloud computing and data analytics to provide real-time data interpretation.
Abstract: In the last decade or so, the wearable electronics technology has seen an unprecedented growth which is expected to reach around USD 51.60 billion by the year 2022 with a CAGR of 15.51%. Intelligent wearable electronics is a combination of wide range of technologies like computation, communication, sensors, cloud computing, and display to cite a few. Integration of various technologies result in systems which are multifunctional along with higher complexity of design presenting a unique challenge for the technologists. With Internet of Things (IoTs) becoming ubiquitous and 5G technologies around the corner, the wearable devices are no longer simple passive systems providing the user limited information, but rather they are multifunctional, powerful, and intelligent devices which make use of complex sensing and signal processing elements along with cloud computing and data analytics to provide real-time data interpretation.
4 citations
Journal Article•
TL;DR: In this paper, a triaxial MEMS accelerometer measurements of static acceleration (angles relative to gravity) and dynamic accelerations are used to obtain 3D ground acceleration and permanent deformation profiles up to a depth of one hundred meters.
Abstract: The use of Micro-Electro-Mechanical Systems (MEMS) accelerometers in geotechnical instrumentation is relatively new but on the rise. This paper describes a new MEMS-based system for in situ deformation and vibration monitoring. The system has been developed in an effort to combine recent advances in the miniaturization of sensors and electronics with an established wireless infrastructure for on-line geotechnical monitoring. The concept is based on triaxial MEMS accelerometer measurements of static acceleration (angles relative to gravity) and dynamic accelerations. The dynamic acceleration sensitivity range provides signals proportional to vibration during earthquakes or construction activities. This MEMS-based in-place inclinometer system utilizes the measurements to obtain three-dimensional (3D) ground acceleration and permanent deformation profiles up to a depth of one hundred meters. Each sensor array or group of arrays can be connected to a wireless earth station to enable real-time monitoring as well as remote sensor configuration. This paper provides a technical assessment of MEMS-based in-place inclinometer systems for geotechnical instrumentation applications by reviewing the sensor characteristics and providing small- and full-scale laboratory calibration tests. A description and validation of recorded field data from an instrumented unstable slope in California is also presented.
3 citations
TL;DR: In this paper, the experimental, analytical and numerical dynamic analysis of SU-8 polymer MEMS mass-spring systems using two different attachment beams, dual and quad, was presented.
Abstract: This paper presents the experimental, analytical and numerical dynamic analysis of SU-8 polymer MEMS mass-spring systems using two different attachment beams, dual and quad. Beam thicknesses of $4.48~\mu \text{m}$ and $8.21~\mu \text{m}$ produce two different sets of prototypes using dual-beam attachments. Those using quad-beam are only $8.21~\mu \text{m}$ thick. Using Lazer Doppler Vibrometer (LDV), dynamic characterization is performed to measure respective resonance frequencies of 1325 Hz and 1813 Hz for dual and quad-beam attachments having a thickness of $8.21~\mu \text{m}$ . Numerical and analytical dynamic analysis are performed to investigate the frequency response of systems using both attachment structures. Using measured key geometric dimensions, numerical and analytical resonance frequencies are evaluated. Theoretical and experimental values are in good agreement with maximum errors of 16% and 12% for dual and quad-beam structures, respectively. The low-cost microfabrication process can be used to incorporate a piezoresistive material/nanomaterial in locations of maximum stress on the beams producing dual and quad-beam MEMS piezoresistive sensors. Numerical analysis is performed to show that the resonance frequency is not affected which proves that the developed dynamic analysis stays valid.
1 citations
Additional excerpts
...weight, of the proof-mass [23]–[25]....
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References
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TL;DR: This work introduces a large area, flexible piezoelectric material that consists of sheets of electrospun fibres of the polymer poly[(vinylidenefluoride-co-trifluoroethylene] in order to enable ultra-high sensitivity for measuring pressure, even at exceptionally small values (0.1 Pa).
Abstract: Multifunctional capability, flexible design, rugged lightweight construction and self-powered operation are desired attributes for electronics that directly interface with the human body or with advanced robotic systems. For these applications, piezoelectric materials, in forms that offer the ability to bend and stretch, are attractive for pressure/force sensors and mechanical energy harvesters. Here, we introduce a large area, flexible piezoelectric material that consists of sheets of electrospun fibres of the polymer poly[(vinylidenefluoride-co-trifluoroethylene]. The flow and mechanical conditions associated with the spinning process yield free-standing, three-dimensional architectures of aligned arrangements of such fibres, in which the polymer chains adopt strongly preferential orientations. The resulting material offers exceptional piezoelectric characteristics, to enable ultra-high sensitivity for measuring pressure, even at exceptionally small values (0.1 Pa). Quantitative analysis provides detailed insights into the pressure sensing mechanisms, and establishes engineering design rules. Potential applications range from self-powered micro-mechanical elements, to self-balancing robots and sensitive impact detectors.
1,004 citations
TL;DR: In this paper, an optomechanical accelerometer that makes use of ultrasensitive displacement readout using a photonic-crystal nanocavity monolithically integrated with a nanotethered test mass of high mechanical Q-factor is presented.
Abstract: The monitoring of acceleration is essential for a variety of applications ranging from inertial navigation to consumer electronics. Typical accelerometer operation involves the sensitive displacement measurement of a flexibly mounted test mass, which can be realized using capacitive, piezo-electric, tunnel-current or optical methods. Although optical detection provides superior displacement resolution, resilience to electromagnetic interference and long-range readout, current optical accelerometers either do not allow for chip-scale integration or utilize relatively bulky test mass sensors of low bandwidth. Here, we demonstrate an optomechanical accelerometer that makes use of ultrasensitive displacement readout using a photonic-crystal nanocavity monolithically integrated with a nanotethered test mass of high mechanical Q-factor This device achieves an acceleration resolution of 10 µg Hz^(−1/2) with submilliwatt optical power, bandwidth greater than 20 kHz and a dynamic range of greater than 40 dB. Moreover, the nanogram test masses used here allow for strong optomechanical backaction, setting the stage for a new class of motional sensors.
590 citations
TL;DR: The results of the flight and ground experimentation are presented and the challenges for using these strapdown devices on rolling projectiles are described.
Abstract: Low-cost micromachined, inertial measurement sensors have steadily emerged into the commercial marketplace. Some of these sensors were evaluated through ground and flight experiments for their insertion potential into military applications like operational test and evaluation and smart munition guidance. Performance requirements for navigation and time space position information (TSPI) are fast approaching those needed, especially when integrated with a Global Positioning System (GPS). Artillery and rockets, instrumented with "automobile grade" microelectromechanical (MEMS) accelerometers and telemetry units, were recently part of a flight experiment which resulted in good success. The results of a high-g shock study suggest that some of these sensors are rugged enough to survive both low-g and high-g launch. Analyzes of the accelerometer data show good comparison to radar-based acceleration measurements and 6-degree-of-freedom trajectory simulations. Flight simulated ground experimentation with gyroscopes have also been conducted that show promise for measuring projectile pitching and yawing behavior. Recent flight experiments may also be available for comparison to ground based measurement devices. This paper presents the results of the flight and ground experimentation and describe the challenges for using these strapdown devices on rolling projectiles.
118 citations
TL;DR: In this paper, a hybrid polymer concrete bed composed of welded steel structure faces and polymer concrete core was designed and manufactured for a high-speed gantry type milling machine through static and dynamic analyses using finite element method.
Abstract: To maximize the productivity of precision products such as molds and dies, machine tools should be operated at high speeds without vibration. As the operation speeds of machine tools are increased, the vibration problem has become a major constraint of manufacturing of precision products. The two important functional requirements of machine tool bed for precision machine tools are high structural stiffness and high damping, which cannot be satisfied simultaneously if conventional metallic materials are used for bed structure because conventional high stiffness metals have low damping and vice versa. This paper presents the application of hybrid polymer concrete for precision machine tool beds. The hybrid polymer concrete bed composed of welded steel structure faces and polymer concrete core was designed and manufactured for a high-speed gantry type milling machine through static and dynamic analyses using finite element method. The developed hybrid machine tool bed showed good damping characteristics over wide range of frequency (η = 2.93–5.69%) and was stable during high speed machining process when the spindle angular speed and acceleration of slide were 35,000 rpm and 30 m/s2, respectively.
88 citations
TL;DR: The CMOS compatible bulk micromachined piezoresistive accelerometer presented in this paper consists of four flexures supporting a proof mass, and dual-doped TMAH solution is used for wet anisotropic etching and exhibits good linearity over 0–10 g.
61 citations