Design Of Accelerometer Research Articles

Broadband optical antireflection metasurface design for F-P micro-optical accelerometers

The micro-optical accelerometer has the advantages of high sensitivity, miniaturization, and integration, which has attracted much attention. Its performance is closely related to parameters such as the intensity and bandwidth of the transmitted light of the optical resonator. Therefore, a novel, to our knowledge, single-layer all-dielectric antireflection structure based on metasurfaces is proposed. According to the quantitative relationship between the reflectivity and the diffraction component of the structure, the antireflection mechanism of the structure is explored. Then, by optimizing the structural parameters of the silicon surface unit, a broadband antireflection range from 415 to 3200 nm is realized, and the transmittance at 1550 nm can reach 99.8%. Finally, the designed metasurface structure is applied to the Fabry–Perot (F-P) micro-optical accelerometer, and the sensitivity is three times higher than that of the Al2O3 antireflection film. This provides what we believe is a new idea for the integrated design of micro-optical accelerometer based on all-dielectric metasurfaces.

Nanoscale dual-axis accelerometer based on a cross-shaped MIM waveguide structure.

This paper details the design and simulation of a dual-axis accelerometer based on the cross-shaped MIM waveguide structure, in which mass blocks are set in the middle of metal sheets inside the resonant cavities as acceleration-sensitive elements. To maintain the balance between the sensitivity and accuracy of the accelerometer, the optimal surface plasmon resonances (SPRs) are discussed to determine the relationship between resonance wavelength and acceleration. Firstly, the performances of two single-axis accelerometers are evaluated within the range of -20 g to 20 g, and the fitting results indicate that the wavelengths of specific SPRs are linearly related to the acceleration. The maximum sensitivities of the x-axis and y-axis accelerometers are 0.15 nm/g and 0.31 nm/g, respectively. After that, a dual-axis accelerometer is designed based on the structural features of the two single-axis accelerometers, achieving the maximum acceleration sensitivity Sa and FOM of 0.16 nm/g and 0.0015g-1 along the x-axis, and 0.30 nm/g and 0.0077g-1 along the y-axis. As a result, this design implements high-precision independent dual-axis acceleration sensing and presents substantial potential for application in diverse nano-scale acceleration sensing fields.

A Micromachined Silicon-on-Glass Accelerometer with an Optimized Comb Finger Gap Arrangement.

This paper reports the design, fabrication, and characterization of a MEMS capacitive accelerometer with an asymmetrical comb finger arrangement. By optimizing the ratio of the gaps of a rotor finger to its two adjacent stator fingers, the sensitivity of the accelerometer is maximized for the same comb finger area. With the fingers' length, width, and depth at 120 μm, 4 μm, and 45 μm, respectively, the optimized finger gap ratio is 2.5. The area of the proof mass is 750 μm × 560 μm, which leads to a theoretical thermomechanical noise of 9 μg/√Hz. The accelerometer has been fabricated using a modified silicon-on-glass (SOG) process, in which a groove is pre-etched into the glass to hold the metal electrode. This SOG process greatly improves the silicon-to-glass bonding yield. The measurement results show that the resonant frequency of the accelerometer is about 2.05 kHz, the noise floor is 28 μg/√Hz, and the nonlinearity is less than 0.5%.

A novel design of a MEMS resonant accelerometer with adjustable sensitivity

This paper presents the design and experimental evaluation of a silicon micro-machined resonant accelerometer featuring adjustable sensitivity. By integrating an electrostatic tuning module into the fundamental accelerometer structure, dynamic sensitivity adjustment becomes feasible, leveraging the softening effect of electrostatic negative stiffness to optimize range, noise, and bandwidth. Notably, the electrostatic tuning module integrates seamlessly with the core accelerometer structure, minimizing structural alterations. Through theoretical analysis and finite element simulation of the electrostatic negative stiffness principle, we have designed a novel accelerometer with adjustable sensitivity, which can enhance the sensitivity and reduces the bias-instability of the accelerometer with a relatively small adjustment voltage, without increasing structural complexity. The performance of the accelerometer was assessed through open-loop, closed-loop, and dynamic experiments, revealing that sensitivity increased from 843 Hz/g to 2611 Hz/g within a linear range of ±1 g when employing a sensitivity-enhancing bias voltage of 9 V. Moreover, the bias-instability is lowered down from 17.3 μg to 6.8 μg. This design offers a promising avenue for sensitivity tuning in MEMS resonant accelerometers.

Polymeric piezoelectric accelerometers with high sensitivity, broad bandwidth, and low noise density for organic electronics and wearable microsystems

Piezoelectric accelerometers excel in vibration sensing. In the emerging trend of fully organic electronic microsystems, polymeric piezoelectric accelerometers can be used as vital front-end components to capture dynamic signals, such as vocal vibrations in wearable speaking assistants for those with speaking difficulties. However, high-performance polymeric piezoelectric accelerometers suitable for such applications are rare. Piezoelectric organic compounds such as PVDF have inferior properties to their inorganic counterparts such as PZT. Consequently, most existing polymeric piezoelectric accelerometers have very unbalanced performance metrics. They often sacrifice resonance frequency and bandwidth for a flat-band sensitivity comparable to those of PZT-based accelerometers, leading to increased noise density and limited application potentials. In this study, a new polymeric piezoelectric accelerometer design to overcome the material limitations of PVDF is introduced. This new design aims to simultaneously achieve high sensitivity, broad bandwidth, and low noise. Five samples were manufactured and characterized, demonstrating an average sensitivity of 29.45 pC/g within a ± 10 g input range, a 5% flat band of 160 Hz, and an in-band noise density of 1.4 µg/Hz\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sqrt{{Hz}}$$\\end{document}. These results surpass those of many PZT-based piezoelectric accelerometers, showing the feasibility of achieving comprehensively high performance in polymeric piezoelectric accelerometers to increase their potential in novel applications such as organic microsystems.

Designs of Optomechanical Acceleration Sensors with the Natural Frequency from 5 Hz to 50 kHz

In many applications, such as space navigation, metrology, testing, and geodesy, it is necessary to measure accelerations with frequencies ranging from fractions of a hertz to several kilohertz. For this purpose, optomechanical sensors are used. The natural frequency of such sensors should be approximately ten times greater than the frequency of the measured acceleration. In the case of triaxial acceleration measurements, a planar design with two sensors that measure accelerations in two perpendicular in-plane directions and a third sensor that measures out-of-plane acceleration is effective. The mechanical characteristics of the existing designs of both in-plane and out-of-plane types of sensors were analyzed, and the improved designs were elaborated. Using numerical simulation, the dependencies of the natural frequency level in the range from several hertz to tens of kilohertz on the designs and geometric parameters of opto-mechanical accelerometers were modeled. This allows one to select the accelerometer design and its parameters to measure the acceleration at the assigned frequency. It is shown that the opto-mechanical accelerometers of the proposed designs have reduced dissipation losses and crosstalk.

High-sensitivity fiber optic graphene resonant accelerometer.

This study proposes a high-sensitivity resonant graphene accelerometer based on a pressure-induced sensing mechanism. The accelerometer design encompasses an optical fiber and a vacuum-sealed graphene resonator affixed to a silicon sensitive film, incorporating a proof mass. This indirect sensing mechanism effectively mitigates the vibration mode aliasing of graphene and the proof mass while ensuring a minimal energy loss in the operating resonator. The mechanical vibration of graphene is excited and detected through an all-fiber optical system. Notably, the proposed sensor demonstrates a sensitivity of 34.3 kHz/g within the range of 0-3.5 g, which is eight times higher than comparable accelerometers utilizing a proof mass on a graphene membrane. This work exhibits a novel, to the best of our knowledge, approach to an acceleration measurement using 2D resonators, exhibiting distinct advantages in terms of compact size and heightened sensitivity.

Design and Sensitivity Analysis of a Micro-Resonant Accelerometer With Adjustable Stiffness

Design and Sensitivity Analysis of a Micro-Resonant Accelerometer With Adjustable Stiffness

Design and simulation of a novel MEMS-based single proof mass three-axis piezo-capacitive accelerometer

Design and simulation of a novel MEMS-based single proof mass three-axis piezo-capacitive accelerometer

The Design, Modeling and Experimental Investigation of a Micro-G Microoptoelectromechanical Accelerometer with an Optical Tunneling Measuring Transducer

This treatise studies a microoptoelectromechanical accelerometer (MOEMA) with an optical measuring transducer built according to the optical tunneling principle (evanescent coupling). The work discusses the design of the accelerometer’s microelectromechanical sensing element (MSE) and states the requirements for the design to achieve a sensitivity threshold of 1 µg m/s2 at a calculated eigenvalue of the MSE. The studies cover the selection of the dimensions, mass, eigenfrequency and corresponding stiffness of the spring suspension, gravity-induced cross-displacements. The authors propose and experimentally test an optical transducer positioning system represented by a capacitive actuator. This approach allows avoiding the restrictions in the fabrication of the transducer conditioned by the extremely high aspect ratio of deep silicon etching (more than 100). The designed MOEMA is tested on three manufactured prototypes. The experiments show that the sensitivity threshold of the accelerometers is 2 µg. For the dynamic range from minus 0.01 g to plus 0.01 g, the average nonlinearity of the accelerometers’ characteristics ranges from 0.7% to 1.62%. For the maximum dynamic range from minus 0.015 g to plus 0.05 g, the nonlinearity ranges from 2.34% to 2.9%, having the maximum deviation at the edges of the regions. The power gain of the three prototypes of accelerometers varies from 12.321 mW/g to 26.472 mW/g. The results provide broad prospects for the application of the proposed solutions in integrated inertial devices.

Sensors, standards and analysis techniques for road transport vibration: A systematic review

This comprehensive review paper analyzes 20 published articles focused on the instrumentation and analysis of road transport vibrations. The study encompasses the distribution of articles based on databases, journals, and publication years, revealing trends in research sources. The examination of sensors and standards emphasizes the critical role of vibration sensor selection and the application of standards, with a focus on accelerometer designs and the prevalence of ASTM D4169-16. The paper delves into various analytical methods, highlighting the frequent use of power spectral density (PSD) and the application of these methods in understanding vibration frequencies and their effects on different transportation conditions. The review identifies key areas for future research, emphasizing the need for refined instrumentation methodologies, standardized standards, and exploration of advanced analytical techniques, considering the dynamic nature of real-world vibrations and emerging technologies in the road transport landscape. Additionally, the review suggests future investigations into optimizing packaging designs and developing innovative materials with vibration-damping properties to enhance the safety and efficiency of road transportation systems.

MEMS capacitive accelerometer: A review

Micro-electro-mechanical systems sensors are integrated systems used in many fields such as consumer electronics, the automobile industry, and biomedical, and their dimensions change between micrometers and millimeters. MEMS capacitive accelerometers are the most widely used sensor type among MEMS accelerometer sensors. As a result of the external force applied to the capacitive accelerometer sensor, the proof mass inside the sensor moves, and the capacitive change is measured as an electrical signal using reading circuits. In this review paper, general information about MEMS sensors is given, and a comprehensive review is made of MEMS capacitive accelerometers. In the study, the dynamic circuit of the MEMS capacitive accelerometer is given, and the calculation of the important values for the mechanical and electronic structure during the design of the capacitive MEMS accelerometer is explained. In addition, information about the readout circuits used to convert the capacitive change to voltage is given. Finally, the fabrication processes used to produce the final product are explained, and the studies on sample fabrication processes found in the literature are mentioned.

IoT Integrated Accelerometer Design and Simulation for Smart Helmets

This article delves into the transformative potential of micro-electromechanical systems (MEMS) accelerometers, particularly their role in revolutionizing helmet safety. Accelerometers, ubiquitous in vehicle manufacturing, computer technology, and audio-video systems, play a crucial role in measuring acceleration. This work focuses on the design and simulation of a rotating accelerometer integrated into football helmets. The introduction of rotational acceleration addresses specific challenges in detecting and mitigating brain injuries that linear accelerometers may encounter. Additionally, the article explores the concept of piezoresistive football helmets, designed to resist force and reduce the impact of concussions. Piezoresistive helmets, designed to resist force and minimize the impact of concussions, when augmented with Internet of Things (IoT) capabilities can create a comprehensive smart safety solution. The incorporation of IoT sensors and connectivity into piezoresistive helmets enables real-time monitoring and data analysis of impact forces. This integration not only enhances player safety by providing immediate insights into potential risks but also opens avenues for injury prevention strategies. Leveraging COMSOL simulation software, this research not only conceives but also realizes the innovative integration of rotational accelerometers and piezoresistive materials in football helmet design, advancing safety standards in sports technology.

A polymeric piezoelectric MEMS accelerometer with high sensitivity, low noise density, and an innovative manufacturing approach

The piezoelectric coupling principle is widely used (along with capacitive coupling and piezoresistive coupling) for MEMS accelerometers. Piezoelectric MEMS accelerometers are used primarily for vibration monitoring. Polymer piezoelectric MEMS accelerometers offer the merits of heavy-metal-free structure material and simple microfabrication flow. More importantly, polymeric piezoelectric MEMS accelerometers may be the basis of novel applications, such as fully organic inertial sensing microsystems using polymer sensors and organic integrated circuits. This paper presents a novel polymer piezoelectric MEMS accelerometer design using PVDF films. A simple and rapid microfabrication flow based on laser micromachining of thin films and 3D stereolithography was developed to fabricate three samples of this design. During proof-of-concept experiments, the design achieved a sensitivity of 21.82 pC/g (equivalent open-circuit voltage sensitivity: 126.32 mV/g), a 5% flat band of 58.5 Hz, and a noise density of 6.02 µg/√Hz. Thus, this design rivals state-of-the-art PZT-based counterparts in charge sensitivity and noise density, and it surpasses the performance capabilities of several commercial MEMS accelerometers. Moreover, this design has a 10-times smaller device area and a 4-times larger flat band than previous state-of-the-art organic piezoelectric MEMS accelerometers. These experimentally validated performance metrics demonstrate the promising application potential of the polymeric piezoelectric MEMS accelerometer design presented in this article.

Equal-strength beam design of acoustic wave accelerometers

Abstract Surface acoustic wave (SAW) based accelerometers have received significant attention due to their digital output, low cost, mass production and easy implementation of wireless passive function. However, conventionally rectangular cantilever-beam based SAW accelerometers often have non-uniform strains generated along the beams, which cause emergence of parasitic wave modes and measurement errors. In this paper, a simulation platform was developed to analyze and optimize designs of SAW accelerometers and variable-thickness and equal-strength beams were designed to solve the critical issue of non-uniform strain distribution along the beam. Frequency responses of SAW accelerometers under the acceleration were successfully obtained using the simulation platform, with the visualized strain/stress distribution and particle displacement field. The accuracy of this simulation platform was verified using the experimental result reported in literature. A highly sensitive and equal-strength beam SAW accelerometer was achieved with a sensitivity up to 1.40 kHz g−1, a linearity coefficient of ∼1, and a measurement range of 0∼15 g. Furthermore, a high-G accelerometer was designed, with the capability of enduring large shocks up to 11,500 g and a sensitivity of 6.96 Hz g−1.

A novel design of capacitive MEMS multi-range accelerometer; FEM and numerical approach

Sensing the acceleration with high dynamic range follows space and size limitations and many errors and inconveniences caused by using multiple accelerometers on a single structure. A novel MEMS capacitive accelerometer with a dual-spring system has been proposed to address this issue. Such a design is a single device with two sensitivities in different sensing ranges. It increases the dynamic range of the sensing by incorporating the supporting springs at high accelerations. Therefore, the sensor can sense a more comprehensive dynamic range while maintaining the required resolution in different ranges. The design parameters of the sensor, such as the thickness of the structural layer, the size of the sensor, and the width of the spring beams, have been investigated. The mechanical sensitivity in the first range is 0.082 μm g−1. For the second range, it is 0.0015 to 0.0091 μm g−1 depending on the supportive springs’ width. Moreover, the natural frequency of the device is 1740 Hz. The capacitance change of the proposed sensor is 7 fF g−1 on average for the first range and 0.08 to 0. 48 fF g−1 for different configurations in the second range. Utilizing such sensors with changeable stiffness in different ranges can reduce the sensor footprint and fabrication cost and increase reliability.

Ultra-high-sensitivity micro-accelerometer achieved by pure axial deformation of piezoresistive beams

Microfabricated piezoresistive accelerometers with purely axially deformed piezoresistive beams have demonstrated high performance. However, the conventional design of such accelerometers requires complex theoretical calculations and specific dimensional conditions to achieve purely axial deformation, which inevitably increases the difficulty and cost of the design and manufacturing. We propose an innovative structure that can simply realize pure axial deformation of piezoresistive beams by eliminating the transverse displacement at both ends without tedious calculations. An accelerometer based on the structure was fabricated; both static and dynamic performances were tested. The results showed that the accelerometer had high sensitivity (2.44 mV g−1 with 5 V bias, without circuit amplification), low cross-axis sensitivity (1.56% and 0.49 %, respectively), and high natural frequency (11.4 kHz), with a measurement range of 0–100 g. This design method provides an easy approach for designing high-performance piezoresistive sensors.

Design of Piezoelectric Dual-Bandwidth Accelerometers for Completely Implantable Auditory Prostheses.

For the last 20 years, researchers have developed accelerometers to function as ossicular vibration sensors in order to eliminate the external components of hearing aid and cochlear implant systems. To date, no accelerometer has met all of the stringent performance requirements necessary to function in this capacity. In this work, we present an accelerometer design with an equivalent noise floor less than 20 phon equal-loudness-level over a 0.1-8 kHz bandwidth in a package small enough to be implanted in the middle ear. Our approach uses a dual-bandwidth (two sensing elements) microelectromechanical systems piezoelectric accelerometer, sized using an area-minimization process based on an experimentally-validated analytical model of the sensor. The resulting bandwidth of the low-frequency sensing element is 0.1-1.25 kHz and that of the high-frequency sensing element is 1.25-8 kHz. These sensing elements fit within a silicon frame that is 795 μm × 778 μm, which can reasonably be housed along with a required integrated circuit in a 2.2 mm × 2.7 mm × 1 mm package. The estimated total mass of the packaged system is approximately 14 mg. This dual-bandwidth MEMS sensor fills a technological gap in current completely implantable auditory prosthesis research and development by enabling a device capable of meeting physical and performance specifications needed for use in the middle ear.

A Double Differential Torsional Accelerometer With Higher Than 10-kHz Measurement Bandwidth for Vibration Monitoring

This paper reports the design, fabrication, ASIC, package, and characterization of a z-axis accelerometer with double differential torsional configuration. Compared with typical comb structures, diagonally large depth non-penetrating quad-mass has a simple structure with a large feature size. Compared with traditional unbalanced proof mass structures, the fully differential sensitive configuration theoretically eliminates the influence of common mode errors such as interference force and temperature variations. Thus a high performance structure with high sensitivity and good stability was obtained. Meanwhile, the anchor was arranged internally to make the structure more compact and less stress sensitive. The sensitive structure has a size of 2.4mm×1.8mm. An optimization of kinetic properties was done to get large bandwidth and small mechanical thermal noise. The ASIC of the double differential torsional structure was implemented, which adopted single-cycle clock double-edge multiplexing to improve C/V conversion efficiency and reduce circuit noise. At the same time, the error compensation technology used on the ASIC makes the accelerometer sensitivity error less than 1% and zero bias error less than ±0.02V. The resonance frequency is about 16kHz, the ±5% bandwidth is larger than 10kHz, the cross-axis sensitivities of the x-axis and y-axis are less than 1.5% and 1%, respectively, the bias instability is less than 700μg, the noise spectral density is better than 30μg/√ Hz above 10Hz, the normalized drift over the full temperature range (-40 °C to 60 °C ) is less than 1.78g under uncompensated conditions.

Design and simulation of dual-axis MEMS accelerometer

Micro electro Mechanical systems (MEMS) are integrated electro-mechanical systems with microscale features. These devices are effective and low power consumers, making them one of the prospective technologies for use in a variety of industries and fields, including as the automotive, consumer, industrial, optical, robotic, biotechnology, medical engineering, and military sectors. MEMS accelerometer is one of the prominent inertial sensor allied in different applications.The proposed work is intended on design, modelling and simulation of a dual axis crab-legged suspension system. By using the SOI MUMPs fabrication process flow formulated by MEMSCAP Foundry a capacitive-based MEMS accelerometer is designed. Natural frequency, cross axis sensitivity, frequency response, and static capacitance analysis are the main design characteristics.Sensor is designed for a low frequency applicatons by assuming a natural frequency of 4KHz, he actual bandwidth vs sensitiviy is about 2KHz and 0.088um/g respectively. The measured stiffness along × and y are kx = 176.089 N/m ky = 176.089 N/m respectively.The proposed design of the capacities sensing comb drive structure is capable of producing linear change of the displacement for applied accelerations between 1 and 1000 g (1 g = 9.8 m/s2), over which the stress values exceed the tensile strength of the silicon material. By using stationary,frequency domain studies and electro-mechanics physics, the simulation is carried out in the COMSOL Multiphysics tool.