Advances in Piezoelectric/Ultrasonic Sensors and Actuators

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Actuators actuators	2.2	3.9	2012	17.7 Days	CHF 2400
Materials materials	3.1	5.8	2008	13.9 Days	CHF 2600
Micromachines micromachines	3.0	5.2	2010	16.2 Days	CHF 2100
Sensors sensors	3.4	7.3	2001	18.6 Days	CHF 2600
Vibration vibration	1.9	3.2	2018	29.3 Days	CHF 1600

15 pages, 12424 KiB

Open AccessArticle

The Frequency-Variable Rotor-Blade-Based Two-Degree-of-Freedom Actuation Principle for Linear and Rotary Motion

by Xiaotao Li, Shengjiang Wang, Xiangyou Peng, Guan Xu, Jingshi Dong, Fengjun Tian and Qiuyu Zhang

Sensors 2023, 23(19), 8314; https://doi.org/10.3390/s23198314 - 8 Oct 2023

Cited by 1 | Viewed by 1380

Abstract

Piezoelectric accurate actuation plays an important role in industrial applications. The intrinsic frequency of previous actuators is invariable. However, variable frequency can approach the range near the low-intrinsic-frequency and realize a high actuation capability. The frequency-variable linear and rotary motion (FVLRM) principle is [...] Read more.

Piezoelectric accurate actuation plays an important role in industrial applications. The intrinsic frequency of previous actuators is invariable. However, variable frequency can approach the range near the low-intrinsic-frequency and realize a high actuation capability. The frequency-variable linear and rotary motion (FVLRM) principle is proposed for rotor-blade-based two-degree-of-freedom driving. Inertial force is generated by frequency-variable piezoelectric oscillators (FVPO), the base frequency and vibration modes of which are adjustable by the changeable mass and position of the mass block. The variable-frequency principle of FVPO and the FVLRM are recognized and verified by the simulations and experiments, respectively. The experiments show that the FVLRM prototype moves the fastest when the mass block is placed at the farthest position and the prototype is at the second-order intrinsic frequencies of 42 Hz and 43 Hz, achieving a linear motion of 3.52 mm/s and a rotary motion of 286.9 mrad/s. The actuator adopts a lower operating frequency of less than 60 Hz and has the function of adjusting the natural frequency. It can achieve linear and rotational motion with a larger working stroke with 140 mm linear movement and 360° rotation. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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11 pages, 2466 KiB

Open AccessArticle

Ultrasonic Signal Time-Expansion Using DAC Frequency Modulation

by Massimiliano Rossi and Marco Frasca

Vibration 2023, 6(3), 466-476; https://doi.org/10.3390/vibration6030029 - 27 Jun 2023

Viewed by 1466

Abstract

Ultrasonic signals can be conveniently recorded using modern high-speed analog-to-digital converters and analyzed through digital signal processing algorithms. Sometimes, in some applications, such as in bioacoustics, it is necessary to convert digital data to analog signals with a special transformation that allows compressing [...] Read more.

Ultrasonic signals can be conveniently recorded using modern high-speed analog-to-digital converters and analyzed through digital signal processing algorithms. Sometimes, in some applications, such as in bioacoustics, it is necessary to convert digital data to analog signals with a special transformation that allows compressing and translating the spectrum toward audible frequencies. The process is called time expansion and can be conveniently achieved by slowing down the frequency clock of a digital-to-analog converter. This paper analyzes in detail the spectral characteristics of a time-expanded signal. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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17 pages, 9084 KiB

Open AccessArticle

A Driving Power Supply for Piezoelectric Transducers Based on an Improved LC Matching Network

by Ye Feng, Yang Zhao, Hao Yan and Huafeng Cai

Sensors 2023, 23(12), 5745; https://doi.org/10.3390/s23125745 - 20 Jun 2023

Cited by 4 | Viewed by 2435

Abstract

In the ultrasonic welding system, the ultrasonic power supply drives the piezoelectric transducer to work in the resonant state to realize the conversion of electrical energy into mechanical energy. In order to obtain stable ultrasonic energy and ensure welding quality, this paper designs [...] Read more.

In the ultrasonic welding system, the ultrasonic power supply drives the piezoelectric transducer to work in the resonant state to realize the conversion of electrical energy into mechanical energy. In order to obtain stable ultrasonic energy and ensure welding quality, this paper designs a driving power supply based on an improved LC matching network with two functions, frequency tracking and power regulation. First, in order to analyze the dynamic branch of the piezoelectric transducer, we propose an improved LC matching network, in which three voltage RMS values are used to analyze the dynamic branch and discriminate the series resonant frequency. Further, the driving power system is designed using the three RMS voltage values as feedback. A fuzzy control method is used for frequency tracking. The double closed-loop control method of the power outer loop and the current inner loop is used for power regulation. Through MATLAB software simulation and experimental testing, it is verified that the power supply can effectively track the series resonant frequency and control the power while being continuously adjustable. This study has promising applications in ultrasonic welding technology with complex loads. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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21 pages, 10551 KiB

Open AccessArticle

Squeeze Film Effect in Surface Micromachined Nano Ultrasonic Sensor for Different Diaphragm Displacement Profiles

by Avik Ghosh Dastidar, Reshmi Maity, Ramesh Chandra Tiwari, Dejan Vidojevic, Tijana S. Kevkic, Vojkan Nikolic, Subhajit Das and Niladri Pratap Maity

Sensors 2023, 23(10), 4665; https://doi.org/10.3390/s23104665 - 11 May 2023

Cited by 8 | Viewed by 2013

Abstract

In the present paper, we have analytically explored the small variations of the local pressure in the trapped air film of both sides of the clamped circular capacitive micromachined ultrasonic transducer (CMUT), which consists of a thin movable membrane of silicon nitride (Si [...] Read more.

In the present paper, we have analytically explored the small variations of the local pressure in the trapped air film of both sides of the clamped circular capacitive micromachined ultrasonic transducer (CMUT), which consists of a thin movable membrane of silicon nitride (Si₃N₄). This time-independent pressure profile has been investigated thoroughly by solving the associated linear Reynold’s equation in the framework of three analytical models, viz. membrane model, plate model, and non-local plate model. The solution involves Bessel functions of the first kind. The Landau–Lifschitz fringing technique has been assimilated to engrave the edge effects in estimation of the capacitance of CMUT, which should be considered in the micrometer or lesser dimension. To divulge the dimension-based efficacy of the considered analytical models, various statistical methods have been employed. Our use of contour plots of absolute quadratic deviation revealed a very satisfactory solution in this direction. Though the analytical expression of the pressure profile is very cumbersome in various models, the analysis of these outputs exhibits that the pressure profile follows the displacement profile in all the cases indicating no viscous damping. A finite element model (FEM) has been used to validate the systematic analyses of displacement profiles for several radii and thicknesses of the CMUT’s diaphragm. The FEM result is further corroborated by published experimental results bearing excellent outcome. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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13 pages, 11223 KiB

Open AccessArticle

Biaxial Piezoelectric MEMS Mirrors with Low Absorption Coating for 1550 nm Long-Range LIDAR

by L. Mollard, J. Riu, S. Royo, C. Dieppedale, A. Hamelin, A. Koumela, T. Verdot, L. Frey, G. Le Rhun, G. Castellan and C. Licitra

Micromachines 2023, 14(5), 1019; https://doi.org/10.3390/mi14051019 - 9 May 2023

Cited by 7 | Viewed by 2397

Abstract

This paper presents the fabrication and characterization of a biaxial MEMS (MicroElectroMechanical System) scanner based on PZT (Lead Zirconate Titanate) which incorporates a low-absorption dielectric multilayer coating, i.e., a Bragg reflector. These 2 mm square MEMS mirrors, developed on 8-inch silicon wafers using [...] Read more.

This paper presents the fabrication and characterization of a biaxial MEMS (MicroElectroMechanical System) scanner based on PZT (Lead Zirconate Titanate) which incorporates a low-absorption dielectric multilayer coating, i.e., a Bragg reflector. These 2 mm square MEMS mirrors, developed on 8-inch silicon wafers using VLSI (Very Large Scale Integration) technology are intended for long-range (>100 m) LIDAR (LIght Detection And Ranging) applications using a 2 W (average power) pulsed laser at 1550 nm. For this laser power, the use of a standard metal reflector leads to damaging overheating. To solve this problem, we have developed and optimised a physical sputtering (PVD) Bragg reflector deposition process compatible with our sol-gel piezoelectric motor. Experimental absorption measurements, performed at 1550 nm and show up to 24 times lower incident power absorption than the best metallic reflective coating (Au). Furthermore, we validated that the characteristics of the PZT, as well as the performance of the Bragg mirrors in terms of optical scanning angles, were identical to those of the Au reflector. These results open up the possibility of increasing the laser power beyond 2W for LIDAR applications or other applications requiring high optical power. Finally, a packaged 2D scanner was integrated into a LIDAR system and three-dimensional point cloud images were obtained, demonstrating the scanning stability and operability of these 2D MEMS mirrors. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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12 pages, 3024 KiB

Open AccessArticle

Axial Load Measurement of Bolts with Different Clamping Lengths Based on High-Frequency Ultrasonic ZnO Film Sensor

by Xuechao Jing, Hongwei Dai, Wanli Xu, Yue Zhao, Jun Zhang and Bing Yang

Sensors 2023, 23(7), 3712; https://doi.org/10.3390/s23073712 - 3 Apr 2023

Cited by 2 | Viewed by 2649

Abstract

The ultrasonic testing method has been widely used for measuring the axial load of bolts. However, systematic calibrations are prerequisite if specific bolts have different clamping length configurations, which leads to low efficiency and measurement errors. The focus of this work was to [...] Read more.

The ultrasonic testing method has been widely used for measuring the axial load of bolts. However, systematic calibrations are prerequisite if specific bolts have different clamping length configurations, which leads to low efficiency and measurement errors. The focus of this work was to measure the axial load of bolts with different clamping lengths by proposing a method of clamping length correction based on piezoelectric films in order to avoid the complicated calibration steps. Firstly, the relationship between longitudinal wave time-of-flight (TOF) and axial load under different clamping lengths was studied to correct the difference between the effective stress length and the actual clamping length. Secondly, the high-frequency ZnO piezoelectric film sensor was fabricated on the bolts to improve the accuracy of longitudinal wave TOF measurement. The results showed that the center frequency of the fabricated ultrasonic sensor reached 25 MHz, which could realize the high precision measurement of TOF. The proposed correction model proved to be effective for decreasing the measurement error below 2.7% in this experiment. In conclusion, the proposed method simplified the calibration procedure for different application configurations of the same bolt and realized the efficient measurement of bolt axial load. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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16 pages, 6535 KiB

Open AccessArticle

Development of a Low-Frequency Piezoelectric Ultrasonic Transducer for Biological Tissue Sonication

by Vytautas Ostasevicius, Vytautas Jurenas, Sandra Mikuckyte, Joris Vezys, Edgaras Stankevicius, Algimantas Bubulis, Mantas Venslauskas and Laura Kizauskiene

Sensors 2023, 23(7), 3608; https://doi.org/10.3390/s23073608 - 30 Mar 2023

Cited by 5 | Viewed by 4242

Abstract

The safety of ultrasound exposure is very important for a patient’s well-being. High-frequency (1–10 MHz) ultrasound waves are highly absorbed by biological tissue and have limited therapeutic effects on internal organs. This article presents the results of the development and application of a [...] Read more.

The safety of ultrasound exposure is very important for a patient’s well-being. High-frequency (1–10 MHz) ultrasound waves are highly absorbed by biological tissue and have limited therapeutic effects on internal organs. This article presents the results of the development and application of a low-frequency (20–100 kHz) ultrasonic transducer for sonication of biological tissues. Using the methodology of digital twins, consisting of virtual and physical twins, an ultrasonic transducer has been developed that emits a focused ultrasound signal that penetrates into deeper biological tissues. For this purpose, the ring-shaped end surface of this transducer is excited not only by the main longitudinal vibrational mode, which is typical of the flat end surface transducers used to date, but also by higher mode radial vibrations. The virtual twin simulation shows that the acoustic signal emitted by the ring-shaped transducer, which is excited by a higher vibrational mode, is concentrated into a narrower and more precise acoustic wave that penetrates deeper into the biological tissue and affects only the part of the body to be treated, but not the whole body. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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14 pages, 4490 KiB

Open AccessArticle

Theoretical and Experimental Studies on Sensitivity and Bandwidth of Thickness-Mode Driving Hydrophone Utilizing A 2-2 Piezoelectric Single Crystal Composite

by Yub Je, Minseop Sim, Yohan Cho, Sang-Goo Lee and Hee-Seon Seo

Sensors 2023, 23(7), 3445; https://doi.org/10.3390/s23073445 - 24 Mar 2023

Cited by 6 | Viewed by 2877

Abstract

Piezoelectric composites, which consist of a piezoelectric material and a polymer, have been extensively studied for the applications of underwater sonar sensors and medical diagnostic ultrasonic transducers. Acoustic sensors utilizing piezoelectric composites can have a high sensitivity and wide bandwidth because of their [...] Read more.

Piezoelectric composites, which consist of a piezoelectric material and a polymer, have been extensively studied for the applications of underwater sonar sensors and medical diagnostic ultrasonic transducers. Acoustic sensors utilizing piezoelectric composites can have a high sensitivity and wide bandwidth because of their high piezoelectric coefficient and low acoustic impedance compared to single-phase piezoelectric materials. In this study, a thickness-mode driving hydrophone utilizing a 2-2 piezoelectric single crystal composite was examined. From the theoretical and numerical analysis, material properties that determine the bandwidth and sensitivity of the thickness-mode piezoelectric plate were derived, and the voltage sensitivity of piezoelectric plates with various configurations was compared. It was shown that the 2-2 composite with [011] poled single crystals and epoxy polymers can provide high sensitivity and wide bandwidth when used for hydrophones with a thickness resonance mode. The hydrophone element was designed and fabricated to have a thickness mode at a frequency around 220 kHz by attaching a composite plate of quarter-wavelength thickness to a hard baffle. The fabricated hydrophone demonstrated an open circuit voltage sensitivity of more than −180 dB re 1 V/μPa at the resonance frequency and a −3 dB bandwidth of more than 55 kHz. The theoretical and experimental studies show that the 2-2 single crystal composite can have a high sensitivity and wide bandwidth compared to other configurations of piezoelectric elements when they are used for thickness-mode hydrophones. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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10 pages, 6101 KiB

Open AccessArticle

Design and Analysis of Lithium–Niobate-Based Laterally Excited Bulk Acoustic Wave Resonator with Pentagon Spiral Electrodes

by Ying Xie, Wenjuan Liu, Yao Cai, Zhiwei Wen, Tiancheng Luo, Yan Liu and Chengliang Sun

Micromachines 2023, 14(3), 552; https://doi.org/10.3390/mi14030552 - 26 Feb 2023

Cited by 3 | Viewed by 2580

Abstract

In this paper, we present a comprehensive study on the propagation and dispersion characteristics of A₁ mode propagating in Z-cut LiNbO₃ membrane. The A₁ mode resonators with pentagon spiral electrodes utilizing Z-cut lithium niobate (LiNbO₃) thin film are [...] Read more.

In this paper, we present a comprehensive study on the propagation and dispersion characteristics of A₁ mode propagating in Z-cut LiNbO₃ membrane. The A₁ mode resonators with pentagon spiral electrodes utilizing Z-cut lithium niobate (LiNbO₃) thin film are designed and fabricated. The proposed structure excites the A₁ mode waves in both x- and y-direction by utilizing both the piezoelectric constants e₂₄ and e₁₅ due to applying voltage along both the x- and y-direction by arranging pentagon spiral electrode. The fabricated resonator operates at 5.43 GHz with no spurious mode and effective electromechanical coupling coefficient (

K_{e f f}^{2}

) of 21.3%, when the width of electrode is 1 µm and the pitch is 5 µm. Moreover, we present a comprehensive study of the effect of different structure parameters on resonance frequency and

K_{e f f}^{2}

of XBAR. The

K_{e f f}^{2}

keeps a constant with varied thickness of LiNbO₃ thin film and different electrode rotation angles, while it declines with the increase of p from 5 to 20 µm. The proposed XBAR with pentagon spiral electrodes realize high frequency response with no spurious mode and tunable

K_{e f f}^{2}

, which shows promising prospects to satisfy the needs of various 5 G high-band application. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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11 pages, 2748 KiB

Open AccessArticle

ScAlN Film-Based Piezoelectric Micromechanical Ultrasonic Transducers with Dual-Ring Structure for Distance Sensing

by Yuchao Zhang, Bin Miao, Guanghua Wang, Hongyu Zhou, Shiqin Zhang, Yimin Hu, Junfeng Wu, Xuechao Yu and Jiadong Li

Micromachines 2023, 14(3), 516; https://doi.org/10.3390/mi14030516 - 23 Feb 2023

Cited by 7 | Viewed by 3041

Abstract

Piezoelectric micromechanical ultrasonic transducers (pMUTs) are new types of distance sensors with great potential for applications in automotive, unmanned aerial vehicle, robotics, and smart homes. However, previously reported pMUTs are limited by a short sensing distance due to lower output sound pressure. In [...] Read more.

Piezoelectric micromechanical ultrasonic transducers (pMUTs) are new types of distance sensors with great potential for applications in automotive, unmanned aerial vehicle, robotics, and smart homes. However, previously reported pMUTs are limited by a short sensing distance due to lower output sound pressure. In this work, a pMUT with a special dual-ring structure based on scandium-doped aluminum nitride (ScAlN) is proposed. The combination of a dual-ring structure with pinned boundary conditions and a high piezoelectric performance ScAlN film allows the pMUT to achieve a large dynamic displacement of 2.87 μm/V and a high electromechanical coupling coefficient (

k_{t}^{2}

) of 8.92%. The results of ranging experiments show that a single pMUT achieves a distance sensing of 6 m at a resonant frequency of 91 kHz, the farthest distance sensing registered to date. This pMUT provides surprisingly fertile ground for various distance sensing applications. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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18 pages, 5421 KiB

Open AccessArticle

Design and Manufacture of an Optimised Side-Shifted PPM EMAT Array for Use in Mobile Robotic Localisation

by Ross McMillan, Rory Hampson, Morteza Tabatabaeipour, William Jackson, Dayi Zhang, Konstantinos Tzaferis and Gordon Dobie

Sensors 2023, 23(4), 2012; https://doi.org/10.3390/s23042012 - 10 Feb 2023

Cited by 5 | Viewed by 2237

Abstract

Guided wave Electro Magnetic Acoustic Transducers (EMATs) offer an elegant method for structural inspection and localisation relative to geometric features, such as welds. This paper presents a Lorentz force EMAT construction framework, where a numerical model has been developed for optimising Printed Circuit [...] Read more.

Guided wave Electro Magnetic Acoustic Transducers (EMATs) offer an elegant method for structural inspection and localisation relative to geometric features, such as welds. This paper presents a Lorentz force EMAT construction framework, where a numerical model has been developed for optimising Printed Circuit Board (PCB) coil parameters as well as a methodology for optimising magnet array parameters to a user’s needs. This framework was validated experimentally to show its effectiveness through comparison to an industry built EMAT. The framework was then used to design and manufacture a Side-Shifted Unidirectional Periodic Permanent Magnet (PPM) EMAT for use on a mobile robotic system, which uses guided waves for ranging to build internal maps of a given subject, identifying welded sections, defects and other structural elements. The unidirectional transducer setup was shown to operate in simulation and was then manufactured to compare to the bidirectional transmitter and two-receiver configurations on a localisation system. The unidirectional setup was shown to have clear benefits over the bidirectional setup for mapping an unknown environment using guided waves as there were no dead spots of mapping where signal direction could not be interpreted. Additionally, overall package size was significantly reduced, which in turn allows more measurements to be taken within confined spaces and increases robotic crawler mobility. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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13 pages, 2408 KiB

Open AccessArticle

Evaluation of the Cell Concentration in Suspensions of Human Leukocytes by Ultrasound Imaging: The Influence of Size Dispersion and Cell Type

by Luis Elvira, Alba Fernández, Lucía León, Alberto Ibáñez, Montserrat Parrilla, Óscar Martínez and Javier Jiménez

Sensors 2023, 23(2), 977; https://doi.org/10.3390/s23020977 - 14 Jan 2023

Cited by 3 | Viewed by 1972

Abstract

This work focuses on the use of ultrasound imaging to evaluate the cell concentration of dilute leukocyte suspensions in the range of 10–3000 cells/µL. First, numerical simulations were used to study the influence of the size dispersion and the leukocyte type on the [...] Read more.

This work focuses on the use of ultrasound imaging to evaluate the cell concentration of dilute leukocyte suspensions in the range of 10–3000 cells/µL. First, numerical simulations were used to study the influence of the size dispersion and the leukocyte type on the performance of the concentration estimation algorithms, which were developed in previous works assuming single-sized scatterers. From this analysis, corrections to the mentioned algorithms were proposed and then the performance of these corrections was evaluated from experiments. For this, ultrasound images were captured from suspensions of lymphocytes, granulocytes, and their mixtures. These images were obtained using a 20 MHz single-channel scanning system. Results confirmed that concentration estimates provided by conventional algorithms were affected by the size dispersion of cells, leading to a remarkable underestimation of results. The proposed correction to compensate for cell size dispersion obtained from simulations improved the concentration estimation of these algorithms, for the cell suspensions tested, approaching the results to the reference optical characterization. Moreover, it was shown that these models provided a total leukocyte concentration from the ultrasound images which was independent of the relative populations of different white blood cell types. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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14 pages, 758 KiB

Open AccessArticle

Linear Matrix Inequality Approach to Designing Damping and Tracking Control for Nanopositioning Application

by Adedayo K. Babarinde and Sumeet S. Aphale

Vibration 2022, 5(4), 846-859; https://doi.org/10.3390/vibration5040050 - 29 Nov 2022

Viewed by 1894

Abstract

This paper presents a method to extend the eigenstructure assignment based design of the Positive Position Feedback (PPF) damping controller to the family of well-known second-order Positive Feedback Controllers (PFC) namely: (i) the Positive Velocity and Position Feedback (PVPF) and (ii) the Positive [...] Read more.

This paper presents a method to extend the eigenstructure assignment based design of the Positive Position Feedback (PPF) damping controller to the family of well-known second-order Positive Feedback Controllers (PFC) namely: (i) the Positive Velocity and Position Feedback (PVPF) and (ii) the Positive Acceleration Velocity and Position Feedback (PAVPF) using appropriate eigenstructure assignment. This design problem entails solving a set of linear equations in the controller parameters using Linear Matrix Inequalities (LMI) to specify a convex design constraint. These damping controllers are popularly used in tandem with a tracking controller (typically an integrator) to deliver high-bandwidth nanopositioning performance. Consequently, the closed-loop performance of all three controllers (PPF, PVPF and PAVPF) employed in tandem with suitably gained integral tracking loops is thoroughly quantified via relevant performance metrics, using measured frequency response data from one axis of a piezo-stack actuated x-y nanopositioner. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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9 pages, 2802 KiB

Open AccessArticle

Demonstration of Thin Film Bulk Acoustic Resonator Based on AlN/AlScN Composite Film with a Feasible

K_{e f f}^{2}

by Laixia Nian, Yang Zou, Chao Gao, Yu Zhou, Yuchen Fan, Jian Wang, Wenjuan Liu, Yan Liu, Jeffrey Bowoon Soon, Yao Cai and Chengliang Sun

Micromachines 2022, 13(12), 2044; https://doi.org/10.3390/mi13122044 - 22 Nov 2022

Cited by 7 | Viewed by 3462

Abstract

Film bulk acoustic resonators (FBARs) with a desired effective electromechanical coupling coefficient (

K_{e f f}^{2}

) are essential for designing filter devices. Using AlN/AlScN composite film with the adjustable thickness ratio can be a feasible approach to obtain the required [...] Read more.

Film bulk acoustic resonators (FBARs) with a desired effective electromechanical coupling coefficient (

K_{e f f}^{2}

) are essential for designing filter devices. Using AlN/AlScN composite film with the adjustable thickness ratio can be a feasible approach to obtain the required

K_{e f f}^{2}

. In this work, we research the resonant characteristics of FBARs based on AlN/AlScN composite films with different thickness ratios by finite element method and fabricate FBAR devices in a micro-electromechanical systems process. Benefiting from the large piezoelectric constants, with a 1 μm-thick Al_0.8Sc_0.2N film,

K_{e f f}^{2}

can be twice compared with that of FBAR based on pure AlN films. For the composite films with different thickness ratios,

K_{e f f}^{2}

can be adjusted in a relatively wide range. In this case, a filter with the specific N77 sub-band is demonstrated using AlN/Al_0.8Sc_0.2N composite film, which verifies the enormous potential for AlN/AlScN composite film in design filters. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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16 pages, 6004 KiB

Open AccessArticle

Modeling and Design Optimization of a New Piezoelectric Inchworm Actuator with Screw Clamping Mechanisms

by Haichao Sun, Yunlai Shi, Qiang Wang, Xing Li and Junhan Wang

Micromachines 2022, 13(12), 2038; https://doi.org/10.3390/mi13122038 - 22 Nov 2022

Cited by 3 | Viewed by 2189

Abstract

A new piezoelectric inchworm actuator with screw clamping mechanisms has been developed recently for the wing folding mechanism of a small unmanned aircraft where the actuator power density is a great concern. Considering that the prototype actuator was designed just with engineering intuition [...] Read more.

A new piezoelectric inchworm actuator with screw clamping mechanisms has been developed recently for the wing folding mechanism of a small unmanned aircraft where the actuator power density is a great concern. Considering that the prototype actuator was designed just with engineering intuition and the performance optimization through experimental developments would take a vast amount of cost and time, a mathematical model was developed to investigate the actuator’s critical design parameters and optimize its presently undesirable performance. Based on the lumped parameter method reported previously, and taking full account of the detailed modeling of the complex actuator housing and the actual nonlinear behaviors from the high-force contact and friction occurring at the screw-nut interface, as well as the output performance of the main drive elements including the piezoelectric stack and hollow ultrasonic motors (HUSMs), this model was built and then was experimentally verified for its accuracy and availability. Finally, nine design parameters were studied for their individual effect on the actuator’s output using the proposed model. The simulation results indicate that the performance can be considerably improved by performing a slight modification to the prototype, and the dynamic modeling and parameter optimization methods used in this study can also serve as a useful reference for the design of similar piezoelectric inchworm actuators with intermittent clamping behaviors. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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15 pages, 3668 KiB

Open AccessArticle

Design of Piezopolymer Interdigital Transducers with Scaled Electrode Geometries Based on FEM Analysis

by Lorenzo Capineri, Luca Bergamaschi and Andrea Bulletti

Actuators 2022, 11(11), 326; https://doi.org/10.3390/act11110326 - 8 Nov 2022

Cited by 1 | Viewed by 2223

Abstract

The design of interdigital transducers (IDT) for active structural health monitoring (SHM) systems often requires a tuning of their characteristics for specific applications. IDTs are generally preferred for the selectivity of Lamb’s guided modes, but the directivity of the radiation pattern is a [...] Read more.

The design of interdigital transducers (IDT) for active structural health monitoring (SHM) systems often requires a tuning of their characteristics for specific applications. IDTs are generally preferred for the selectivity of Lamb’s guided modes, but the directivity of the radiation pattern is a design parameter that is often difficult to customize for complex mechanical structures. This work proposes a comprehensive experimental study of the IDT with regular geometry, highlighting the dimensional parameters that can optimize the overall performance. From this study, a scaled electrode geometry emerged as a possible solution to shape the directivity diagram while maintaining the selectivity of the guided wave modes. This study based on FEM simulators led to a more versatile design of IDTs built with piezopolymer films of polyvinylidene fluoride (PVDF). The experimental validation showed the directivity diagrams and the ultrasonic guided mode selection were in very good agreement with the simulations. Another outcome of the investigation was the off axis propagation due to the contribution of the bus bars for connecting the IDT fingers to the excitation electronic circuit. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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16 pages, 8727 KiB

Open AccessArticle

Flow Pattern Identification of Oil–Water Two-Phase Flow Based on SVM Using Ultrasonic Testing Method

by Qian Su, Jie Li and Zhenxing Liu

Sensors 2022, 22(16), 6128; https://doi.org/10.3390/s22166128 - 16 Aug 2022

Cited by 8 | Viewed by 3079

Abstract

A flow pattern identification method combining ultrasonic transmission attenuation with an ultrasonic reflection echo is proposed for oil–water two-phase flow in horizontal pipelines. Based on the finite element method, two-dimensional geometric simulation models of typical oil–water two-phase flow patterns are established, using multiphysics [...] Read more.

A flow pattern identification method combining ultrasonic transmission attenuation with an ultrasonic reflection echo is proposed for oil–water two-phase flow in horizontal pipelines. Based on the finite element method, two-dimensional geometric simulation models of typical oil–water two-phase flow patterns are established, using multiphysics coupling simulation technology. An ultrasonic transducer test system of a horizontal pipeline with an inner 50 mm diameter was built, and flow pattern simulation experiments of oil–water two-phase flow were carried out in the tested field area. The simulation results show that the ultrasonic attenuation coefficient is extracted to identify the W/O&O/W dispersion flow using the ultrasonic transmission attenuation method, and the identification accuracy is 100%. By comparison, using the ultrasonic reflection echo method, the echo duration is extracted as an input feature vector of support vector machine (SVM), and the identification accuracy of the stratified flow and dispersed flow is 95.45%. It was proven that the method of the ultrasonic transmission attenuation principle combined with the ultrasonic reflection echo principle can identify oil–water two-phase flow patterns accurately and effectively, which provides a theoretical basis for the flow pattern identification of liquid–liquid multiphase flow. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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18 pages, 1976 KiB

Open AccessArticle

Relation between Mass Sensitivity and Complex Power Flow in Love Wave Sensors

by Piotr Kiełczyński

Sensors 2022, 22(16), 6100; https://doi.org/10.3390/s22166100 - 15 Aug 2022

Viewed by 1575

Abstract

In this paper, we investigate the connection between average power flows in Love wave waveguides with the mass sensitivity of Love wave sensors. In fact, loading with a Newtonian liquid gives rise to two extra power flows, in the transverse direction towards the [...] Read more.

In this paper, we investigate the connection between average power flows in Love wave waveguides with the mass sensitivity of Love wave sensors. In fact, loading with a Newtonian liquid gives rise to two extra power flows, in the transverse direction towards the loading Newtonian liquid. The first is an active power flow feeding viscous losses in the Newtonian liquid and the second is a reactive power flow that is responsible for the phase delay of the Love wave and consequently for the changes in phase velocity of the Love wave. Since loading with a lossless mass also leads to changes in the phase velocity, we assert that mass sensitivity

S_{σ}^{v_{p}}

of Love wave sensors is connected to the average reactive power flow, in the transverse direction

x_{2}

, bouncing back and forth, between the interior of the waveguide and the loading Newtonian liquid. Subsequently, we found the thickness of the effective surface layer of mass that is equivalent to loading with a semi-infinite Newtonian liquid. The analytical formulas developed in this paper are illustrated by the results of numerical calculations performed for an exemplary Love wave waveguide composed of a PMMA surface layer deposited on an ST-Quartz substrate. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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14 pages, 4544 KiB

Open AccessArticle

Design and Fabrication of High-Frequency Piezoelectric Micromachined Ultrasonic Transducer Based on an AlN Thin Film

by Junbin Zang, Zheng Fan, Penglu Li, Xiaoya Duan, Chunsheng Wu, Danfeng Cui and Chenyang Xue

Micromachines 2022, 13(8), 1317; https://doi.org/10.3390/mi13081317 - 14 Aug 2022

Cited by 13 | Viewed by 3744

Abstract

A piezoelectric micromachined ultrasonic transducer (PMUT) is a microelectromechanical system (MEMS) device that can transmit and receive ultrasonic waves. Given its advantages of high-frequency ultrasound with good directionality and high resolution, PMUT can be used in application scenarios with low power supply, such [...] Read more.

A piezoelectric micromachined ultrasonic transducer (PMUT) is a microelectromechanical system (MEMS) device that can transmit and receive ultrasonic waves. Given its advantages of high-frequency ultrasound with good directionality and high resolution, PMUT can be used in application scenarios with low power supply, such as fingerprint recognition, nondestructive testing, and medical diagnosis. Here, a PMUT based on an aluminum nitride thin-film material is designed and fabricated. First, the eigenfrequencies of the PMUT are studied with multiphysics coupling simulation software, and the relationship between eigenfrequencies and vibration layer parameters is determined. The transmission performance of the PMUT is obtained via simulation. The PMUT device is fabricated in accordance with the designed simple MEMS processing process. The topography of the PMUT vibration layer is determined via scanning electron microscopy, and the resonant frequency of the PMUT device is 7.43 MHz. The electromechanical coupling coefficient is 2.21% via an LCR tester. Full article

(This article belongs to the Topic Advances in Piezoelectric/Ultrasonic Sensors and Actuators)

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