Ultrasonic Transducer Research Papers - Academia.edu (original) (raw)

2025, The Annals of Thoracic Surgery

ments, which provide six degrees of freedom, enabling suturing and knot tying to be performed with relative ease and allowing the surgeon to be ambidextrous, whereas the standard VATS instruments only provide four degrees of freedom. In our case this facilitated the dissection of an avascular plane and ensured there was no communication with the pericardium. Second, computer technology eliminates tremor and provides scaling of motion that enhances tissue manipulation. Third, the computer-enhanced three-dimensional vision system allows direct hand-eye coordination while always maintaining orientational alignment. In our case this improved our ability to identify the phrenic nerve and other critical mediastinal structures. By performing this procedure using robotic technology, the duration of dissection was limited to 15 minutes, which is shorter than our experience using VATS. Despite many advantages over VATS, robotic technology may have some disadvantages. Robotic technology is very expensive when compared with conventional VATS equipment, rendering it unavailable in many centers at the present time. Also, despite the major advances in dexterity and three-dimensional optics with the robotic technology, there is still the lack of tactile feedback that affects the ability to palpate tissue. Lastly, like any new technology, the setup of equipment for robotically assisted procedures may be more time-consuming than either open or VATS procedures, particularly early on in the learning curve. Improvements in computer-enhanced robotic technology are anticipated such as newer-generation systems that are smaller, easier to set up, and more competitively priced. Further refinements such as tactile feedback, which will further enhance tissue handling, knot tying, and suturing, are anticipated. In addition, a fourth robotic arm to simulate an assistant will be necessary to perform more complex cases. The advantages of robotic pericardial cyst resection as demonstrated in this case and the anticipated improvements in robotic technology support the continued use of robotic technology in general thoracic surgery.

2025

Guided wave ultrasonic testing is gaining widespread acceptance as a non-destructive testing tool for rapid screening of process piping and pipelines. The technology detects changes in cross-sectional area and is not currently capable of measuring remaining wall thickness. As a result, anomalies identified by guided wave UT must be quantified by a secondary NDT technique, to provide data suitable for input to a fitness-for-service assessment. This paper describes a philosophy for inspecting piping and pipelines as part of an integrity management programme. The following aspects are covered: Review of the system(s) to be inspected to determine potential corrosion mechanisms; Selection of components for guided wave UT; Ultrasonic based techniques for components unsuitable for guided wave UT, and for confirmation and quantification of anomalies identified by guided wave UT; NDT reporting to ensure data is presented in a suitable format for immediate assessment at API 5791/ASME FFS-1 Le...

2025, Sensors and Actuators A: Physical

2025, Procedia Computer Science

2025, International Journal of Automation and Control

Present research and development in the area of mobile robots mainly aims at study of various techniques, methods and sensors being used for navigation of mobile robots. Different techniques have been discussed for the navigation of mobile robots in the first part. These techniques can be subdivided as (1) fuzzy logic technique, (2) neural network technique and (3) genetic algorithm technique. In the second part, five methods are being discussed for navigation of mobile robots. These methods are (1) potential field method, (2) grid-type method, (3) heuristic method, (4) adaptive navigation method and (v) Virtual Impedance method. The last segment focuses on different sensors being used for navigation of mobile robots. The sensors discussed are (1) ultrasonic sensor, (2) laser sensor, (3) magnetic compass disk sensor, (4) infrared sensor and (5) vision (camera) sensor. Keeping the above strategies in forefront, a comprehensive discussion has been made and is described methodologically in the current paper.

2025, Diagnosis

Ultrasound diagnostics is a non-invasive imaging technique that uses sound waves to create real-time images of internal structures. It is widely used across medical specialties for assessing organs, tissues, and blood flow. Advancements like AI integration, contrast-enhanced ultrasound (CEUS), portable devices, and elastography have improved image quality, accessibility, and diagnostic accuracy. Ultrasound remains a vital tool in modern medicine, enhancing patient care and treatment outcomes.

2025, Polymers

There is a growing interest in multifunctional composites and in the identification of novel applications for recycled materials. In this work, the design and fabrication of multiple particle-loaded polymer composites, including micronized rubber from end-of-life tires, is studied. The integration of these composites as part of ultrasonic transducers can further expand the functionality of the piezoelectric material in the transducer in terms of sensitivity, bandwidth, ringing and axial resolution and help to facilitate the fabrication and use of phantoms for echography. The adopted approach is a multiphase and multiscale one, based on a polymeric matrix with a load of recycled rubber and tungsten powders. A fabrication procedure, compatible with transducer manufacturing, is proposed and successfully used. We also proposed a modelling approach to calculate the complex elastic modulus, the ultrasonic damping and to evaluate the relative influence of particle scattering. It is concluded that it is possible to obtain materials with acoustic impedance in the range 2.35-15.6 MRayl, ultrasound velocity in the range 790-2570 m/s, attenuation at 3 MHz, from 0.96 up to 27 dB/mm with a variation of the attenuation with the frequency following a power law with exponent in the range 1.2-3.2. These ranges of values permit us to obtain most of the material properties demanded in ultrasonic engineering.

2025

Polyvinilidene fluoride (PVDF) single-element transducers for high-frequency (>30 MHz) ultrasound imaging applications have been developed using MEMS (Micro-electro-Mechanical Systems) compatible techniques. Performance of these transducers has been investigated by analyzing the sources and effects of on-chip parasitic capacitances on the insertion-loss of the transducers. Modeling and experimental studies showed that on-chip parasitic capacitances degraded the performance of the transducers and an improved method of fabrication was suggested and new devices were built. New devices developed with minimal parasitic effects were shown to improve the performance significantly. A 1-mm aperture PVDF device developed with minimal parasitic effects has resulted in a reduction of insertion loss of 21 dB compared with devices fabricated using a previous method.

2024, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control

We report on a new operation regime for capacitive micromachined ultrasonic transducers (cMUTs). Traditionally, cMUTs are operated at a bias voltage lower than the collapse voltage of their membranes. In the new proposed operation regime, first the cMUT is biased past the collapse voltage. Second, the bias voltage applied to the collapsed membrane is reduced without releasing the membrane. Third, the cMUT is excited with an ac signal at the bias point, keeping the total applied voltage between the collapse and snapback voltages. In this operation regime, the center of the membrane is always in contact with the substrate. Our finite element methods (FEM) calculations reveal that a cMUT operating in this new regime, between collapse and snapback voltages, possesses a coupling efficiency (k 2 T) higher than a cMUT operating in the conventional regime below its collapse voltage. This paper compares the simulation results of the coupling efficiencies of cMUTs operating in conventional and new operation regimes.

2024

Increasingly, electroactive materials are used to produce actuators, sensors, displays and other elements of mechanisms and devices. In recognition of the potential of these materials, research at the JPL s NDEAA Lab have led to many novel space and terrestrial applications. This effort involves mostly the use of piezoelectric and electroactive polymers (EAP). The piezoelectric based devices and mechanisms that were developed include ultrasonic motors, piezopump, ultrasonic/sonic driller/corer (USDC), and ferrosource. Further, the electroactive polymers were used to demonstrate a gripper, wiper, lifter and haptic interfaces. The research and development tasks consist of analytical modeling, experimental tests and corroboration, material characterization as well as device and mechanisms design, construction and demonstration. This effort is multidisciplinary requiring expertise that is complemented by cooperation with researchers and engineers in the USA and internationally. Some of the innovation has been inspired by nature and biomimetic devices, such as the ultrasonic/sonic gopher, were developed. In this manuscript the research and development activity of the JPL's NDEAA Lab will be reviewed.

2024, International Journal of Metalcasting

Alloy melt treatment by ultrasonic vibration is a physical processing technique that has been gathering the support of the scientific community. The use of metallic sonotrodes for this purpose has been proven very efficient; however, it promotes melt inclusion by sonotrode erosion. Such an issue is being addressed by the use of ceramic sonotrodes in low-amplitude resonance. Given that these novel sonotrodes generally have complex shapes and low displacements, this study shows an innovative approach for their characterization. Based on scanning laser Doppler vibrometry, the signal processing Python-based script was used to map the overall resonant behavior of a tubular SiAlON sonotrode, and this route is able to characterize the complex shapes in low-amplitude and high-frequency radial resonance in resonant ceramic sonotrodes. Velocity time-domain profiles are shown to be dependent on the position, and even though the radial natural frequencies of ceramic sonotrodes have low amplitudes, they are proposed as an efficient tool for melt treatment. While characterizing the radial natural mode in ceramic sonotrodes, this study proves that their low-amplitude Lamb waves are responsible for the refinement of a-grains and secondary phases in light alloys.

2024

This work is about the determination of a parameter of slope of a 6 dof robot. This geometrical parameter of design is related to the singularity of the mechanism. To move away from this singularity we propose a better alternative of this parameter, as being the total maximum of a function, which definite the manipulability expression, the latter which is a big factor for the kinematics performance evaluation of the robot. The parameter founded minimizes the effects of the singularity on the whole of the configurations and softened as well as possible the movements of the articulations of the robot.

2024, Fractals

Piezoelectric ultrasonic transducers have the ability to act both as a receiver and a transmitter of ultrasound. Standard designs have a regular structure and therefore operate effectively over narrow bandwidths due to their single length scale. Naturally occurring transducers benefit from a wide range of length scales giving rise to increased bandwidths. It is therefore of interest to investigate structures which incorporate a range of length scales, such as fractals. This paper applies an adaptation of the Green function renormalization method to analyze the propagation of an ultrasonic wave in a series of pre-fractal structures. The structure being investigated here is the Sierpinski carpet. Novel expressions for the non-dimensionalized electrical impedance and the transmission and reception sensitivities as a function of the operating frequency are presented. Comparisons of metrics between three new designs alongside the standard design (Euclidean structure) and the previously i...

2024, Sensors (Basel, Switzerland)

Piezoelectric ultrasonic transducers have the potential to operate as both a sensor and as an actuator of ultrasonic waves. Currently, manufactured transducers operate effectively over narrow bandwidths as a result of their regular structures which incorporate a single length scale. To increase the operational bandwidth of these devices, consideration has been given in the literature to the implementation of designs which contain a range of length scales. In this paper, a mathematical model of a novel Sierpinski tetrix fractal-inspired transducer for sensor applications is presented. To accompany the growing body of research based on fractal-inspired transducers, this paper offers the first sensor design based on a three-dimensional fractal. The three-dimensional model reduces to an effective one-dimensional model by allowing for a number of assumptions of the propagating wave in the fractal lattice. The reception sensitivity of the sensor is investigated. Comparisons of reception f...

2024

Introduction: A miniature CHEMIN XRD/XRF instrument is currently being developed for definitive mineralogic analysis of soils and rocks on Mars [1]. One of the technical issues that must be addressed in order to enable XRD analysis on an extraterrestrial body is how best to obtain a representative sample powder for analysis. For XRD powder diffraction analyses, it is beneficial to have a fine-grained sample to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the Xray beam [2]. Although a 2-dimensional detector as used in the CHEMIN instrument will produce good results with poorly prepared powders [3], the quality of the data will improve if the sample is fine-grained and randomly oriented. An Ultrasonic/Sonic Driller/Corer (USDC) currently being developed at JPL (Figure 1) is an effective mechanism of sampling rock to produce cores and powdered cuttings. It requires low axial load (< 5N) and thus offers significant advantages for operation from lightweight platforms and in low gravity environments. The USDC is lightweight (<0.5kg), and can be driven at low power (<5W) using duty cycling. It consists of an actuator with a piezoelectric stack, ultrasonic horn, free-mass, and drill bit. The stack is driven with a 20 kHz AC voltage at resonance. The strain generated by the piezoelectric is amplified by the horn by a factor of up to 10 times the displacement amplitude. The tip impacts the free-mass and drives it into the drill bit in a hammering action. The freemass rebounds to interact with the horn tip leading to a cyclic rebound at frequencies in the range of 60-1000 Hz. It does not require lubricants, drilling fluid or bit sharpening and it has the potential to operate at high and low temperatures using a suitable choice of piezoelectric material. To assess whether the powder from an ultrasonic drill would be adequate for analyses by an XRD/XRF spectrometer such as CHEMIN, powders obtained from the JPL ultrasonic drill were analyzed and the results were compared to carefully prepared powders obtained using a laboratory bench scale Retsch mill. Methods: Eight samples representing potential target rocks for a Mars lander were prepared for this study. The samples include igneous volcanic rocks (basalt and andesite), sandstone, and evaporite/spring

2024, Journal of Mechanical Science and Technology

The concept of Time Reversal Acoustics (TRA) provides an elegant possibility of both temporal and spatial concentrating of acoustic energy in highly inhomogeneous media. We explored the possibility of generating acoustical signals with arbitrary waveforms using the TRA Focusing System (TRA FS). A method has been developed to predict TRAfocused ultrasound waveforms and spatial distribution by using the measurements of transfer function of transfer function relating the signal at the TRA transmitter to that at the focusing point. The developed approach for TRA-focused signal waveform prediction from the results of direct signal measurements was tested on ten-channel TRA FS based on aluminum resonator with glued piezotransducers. The TRA FS operated in the frequency band of 100-1000 kHz. The formation of ultrasonic signals with various envelopes was demonstrated experimentally. The calculated and experimentally measured waveforms and spatial distributions were practically identical. We formed triangular, rectangular, and amplitude modulated tone burst signals with different modulation frequencies in the focal region. The level of side lobes in the generated signals was much lower than that for standard TRA focusing.

2024, Smart Structures and Materials 2002: Smart Structures and Integrated Systems

An ultrasonic/sonic driller/corer (USDC) was developed to address the challenges to the NASA objective of planetary in-situ rock sampling and analysis. The USDC uses a novel drive mechanism, transferring ultrasonic vibration into impacts on a drill stem at sonic frequency using a free-flying mass block (free-mass). The main parts of the device and the interactions between them were analyzed and numerically modeled to understand the drive mechanism and allow design of effective drilling mechanism. A computer program was developed to simulate the operation of the USDC and successfully predicted the characteristic behavior of the new device. This paper covers the theory, the analytical models and the algorithms that were developed and the predicted results.

2024, 2001 IEEE Ultrasonics Symposium. Proceedings. An International Symposium (Cat. No.01CH37263)

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2024, Sensors

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

2024, Journal de Physique III

2024, IEEE Transactions on Instrumentation and Measurement

Analyses of threshold-detection and phase-difference techniques for wind-speed measurement using ultrasonic transducers are presented. The influence of uncertainties that are associated with additive noise and attenuation of the ultrasonic signal on the wind-speed measurement uncertainty is analyzed. A data-fusion procedure based on the maximum-likelihood estimation (MLE) algorithm is developed for the determination of wind speed, with data gathered through threshold-detection and phase-difference techniques. The data-fusion procedure provides a lower measurement uncertainty than those obtained with the above techniques when taken separately. Practical design issues are considered, and an application example is shown to illustrate the proposed procedure.

2024

A capacitive micromachined ultrasonic transducer (CMUT) with substrate-embedded springs, called post-CMUT (PCMUT), decouples the spring constant and the mass of the system by realizing the former using relatively long and narrow posts. The PCMUT improves on the fill factor and average volume displacement of the conventional CMUT as shown in our previous work using 3-D finite element analysis (FEA). This work reports on second-generation PCMUT devices designed according to our 3-D FEA simulation results and manufactured using an improved fabrication process flow. This improved fabrication process is composed of three critical steps: wafer bonding of two silicon-on-insulator (SOI) wafers, deep reactiveion etching (DRIE) of posts (i.e. springs), and precision wafer polishing. The improved fabrication process results in a flexible platform for 82-element 1-D arrays, a single element device for high-intensity focused ultrasound (HIFU), and test PCMUT element structures. The new fabrication process also provides better post high uniformity as well as a clear path toward making 2-D arrays.

2024, 2013 IEEE International Ultrasonics Symposium (IUS)

The design of ultrasonic gas flowmeters requires a thorough three dimensional characterization of the acoustic sound field. For large pipe flowmeters, such as used for flare gas metering, the transducers are operated at frequencies ranging from 20 kHz up to 150 kHz. Thus, in this work we use a commercially available calibrated 1/8-inch microphone, mounted on a 3D positioning system for performing volumetric measurements in a volume of up to 1x1x1 m. By using proper corrections in terms of angular and free-field response of the microphone, the measurement system is efficient and delivers around 30000 measurements in about only eight hours. The data then is visualized in form of 3D figures or various slices to extract all relevant information. The system has been used to identify non-uniform velocity profiles in capacitive micromachined ultrasonic transducers (CMUTs), operating in permanent contact mode. Further, the system can be used to investigate the effect of various acoustic boundary conditions the transducers are facing when mounted inside transducer port cavities and it can be used for general model validation purpose.

2024, HAL (Le Centre pour la Communication Scientifique Directe)

In this paper, we compare the movement of two serial robots which are used as probe-holder for the application of tele-echography. The first one is a serial spherical wrist with four degree-of-freedom and the structure of the second one is based on a similar mechanical structure, which is inclined with an angle from the normal direction to the patient's skin. The goal is to compare their trajectories on the plane tangential to the skin and the inclination of the end effector axis.

2024

The friction modulation produced by ultrasonic vibrations is one of the methods which produces the tactile stimulation. The vibration amplitude is modulated depending on the finger position to give the illusion of touching a texture. This thesis aims at developing a tactile device able to simulate the sensation of touching complex textures such as textile fabrics. For this aim, we modelled first the vibration behaviour and proposed a new strategy to track the resonance frequency of the tactile device and to improve the robustness of the control. On the other hand, the relationship between the tribological aspects of interaction finger / stimulator and the perception of stimuli is assessed to define the most perceived tribological criteria. The tribological parameter named "friction contrast" is introduced. Following this tribological study, we developed a new tactile device called SmartTac integrating new force sensors to measure and control directly the coefficient of friction and to make it adaptive to the user's finger. Last, a method for extracting the tribological properties of three various textile fabrics is applied to simulate them. Our method is validated by conducting a psychophysical experiment with a success rate of 78%, matching the simulated surfaces to real surfaces.

2024, Transportation Research Procedia

2024, Ferroelectrics

As widely used sensors and actuators, piezoelectric materials have received great attention. Development of the smart structures can offer a great deal potential for use in advanced industry. This paper discuss the feasibility and efficiency of shape control of piezolaminated composite in antifouling process. The idea is to design an intelligent structural system that is able to protect itself against the fouling.

2024, Ultrasonics

This work describes the use of a large-aperture PVDF receiver in the measurement of liquid density and composite material elastic constants. The density measurement of several liquids is obtained with accuracy of 0.2% using a conventional NDE emitter transducer and a 70-mm-diameter, 52-lm P(VDF-TrFE) membrane with gold electrodes. The determination of the elastic constants is based on the phase velocity measurement. Diffraction can lead to errors around 1% in velocity measurement when using alternatively the conventional pair of ultrasonic transducers (1-MHz frequency and 19-mm-diameter) operating in through-transmission mode, separated by a distance of 100 mm. This effect is negligible when using a pair of 10-MHz, 19-mm-diameter transducers. Nevertheless, the dispersion at 10 MHz can result in errors of about 0.5%, when measuring the velocity in composite materials. The use of an 80-mm diameter, 52-lm-thick PVDF membrane receiver practically eliminates the diffraction effects in phase velocity measurement. The elastic constants of a carbon fiber reinforced polymer were determined and compared with the values obtained by a tensile test.

2024, Journal of the Brazilian Society of Mechanical Sciences and Engineering

The impulse response of the velocity potential and the discrete representation methods were used in order to model the acoustic field radiated by ultrasonic transducers and arrays. The first method deals with the calculation of the exact impulse response, in which solutions are possible only for simple geometries, such as the circular piston. The second method is an approximated solution based on the discretization of the acoustic aperture in small elementary areas, each of them radiating a spherical wave. By using circular transducers, which can be considered circular pistons, many simulations comparing the methods were carried out. The relation between the computational cost and the precision was analyzed, thus establishing the time and space discretization levels. The simulations were made using the Matlab software and the results were compared to experimental measurements showing good agreement. The experimental results were obtained using a scanning system. The acoustic field radiated from a 1 MHz circular transducer was measured as well as a 3.5 MHz array of 16 elements both immersed in water. The acoustic field radiated by the array was simulated and measured with focalization on a radius of 30 mm with deflections of 0° and 20°.

2024, Fractals

2024, Sensors (Basel, Switzerland)

2023

The use of power ultrasound together with supercritical CO 2 is a non-conventional promising technique for extraction processes in food industries. Extraction of almond oil, adlay seed oil, pungent from ginger are good examples of the potential use of this novel technology. In fact, power ultrasound represents an efficient manner of producing agitation in the media enhancing mass transfer on supercritical fluids extraction processes. A prototype for the use of ultrasound in supercritical media is presented in this paper. Special attention has been given to the transducer and its behaviour as a function of power and time during operation. Specific software to control and monitoring the parameters involved in the process has been developed. This tool will allow the best conditions for the operation process to be selected.

2023

In this paper we present a mechanical structure with revolute joints which can be used eventually on a robot and which allows the independent functioning of the positioning and the orientation of the terminal organ.

2023, SPIE Proceedings

Sample return and in-situ sampling and analysis is one of the major objectives of future NASA exploration missions. Existing drilling techniques are limited by the need for large axial forces, holding torques, and high power consumption. Lightweight robots and rovers have difficulties accommodating these requirements. To address these key challenges to the NASA objective of planetary in-situ rock sampling and analysis, a drilling technology called ultrasonic/sonic driller/corer (USDC) was developed. The USDC uses a novel driving mechanism, transferring ultrasonic vibration to sonic frequency impacts with the aid of a free-flying mass block (free-mass). The free mass then drives the drill bit. The actuator consists of a stack of piezoelectric disks with a horn that amplifies the induced vibration amplitudes. The standard USDC is a slender device, and some times its length is too long for specific NASA missions. It is of current interest to have novel designs that reduce the length of the device. For this purpose, two novel horn designs were examined analytically. One is the flipped horn, the other is the planar folded horn. The new designs of the horn were analyzed using finite element modeling and the results allow for the determination of the control parameters that can optimize the performance of the ultrasonic horn in terms of the tip displacement and velocity. The results of the modeling are described and discussed in this paper.

2023

2023, IEEE Access

This work explores the potential applications of biometric recognition in 3D medical imaging data. We investigate various 3D imaging techniques commonly used in the medical domain, including 3D ultrasound imaging, magnetic resonance imaging (MRI), computer tomography (CT) scans, and 3D nearinfrared (NIR) imaging. For each technique, we provide an overview of its working principle and discuss the advantages of integrating biometrics into 3D medical imaging data. Major advantage of using biometrics in this context is motivated by the research that using biometrics could not only increase data security but, more importantly, decrease the mix-up errors in patient's medical data and thus improving patient safety and patient care. Our analysis uncovers certain weaknesses in current algorithms and limitations in existing research. Possible reasons include insufficient data availability, the under-utilization of deep-learning-based approaches to enhance accuracy and performance, and the absence of standardized benchmarking databases to support research. Our survey frames existing works and lead to practical recommendations and motivates efforts to improve the current state of research. Beyond exploring the utilization of biometrics in 3D medical imaging data, our study touches on further potential interactions between them, such as extracting health information from biometric captures. This work is thus the first work to survey and present an overview on works proposing the use of medical images for biometric recognition.

2023, International Journal of Cardiology

We report a patient who initially presented with hoarseness and was admitted to our hospital with chest pain, caused by a saccular aneurysm of the thoracic aortic arch. The initial diagnosis was made by cross-sectional echocardiography, the extension and morphology of the saccular aneurysm being detected by transesophageal echocardiography. Magnetic resonance imaging confirmed the measurements of the aneurysm and clearly showed the anatomic relation with surrounding structures and arch vessels. The patient refused operation and died during in-hospital stay. A rupture of the thoracic aneurysm was the cause of death.

2023

In this paper, we propose a novel redundant robotic forceps system with a modular architecture. We also provide a kinematic solution for the control of the proposed system as well as similar redundant and modular systems. Robots used in laparoscopic surgery usually require 6-7 axes for the positioning of the tool tips of laparoscopic surgery instruments within the patient body. These are cartesian x, y, z, roll, pitch, yaw and grasping axes. The cartesian positioning is achieved by an external Remote Center of Motion (RCM or RCoM) mechanism that can control the position of the instrument tip with a spherical motion at the incision-trocar entry point. While tip cartesian positions are controlled by the external mechanism, the intra-corporeal bending motions are achieved by 3-4 DOF wrist mechanisms which are usually articulated to the RCM mechanisms in macro-micro form. In this paper, we propose a kinematic control method for achieving RCM motion with general 6-7 axis robot arms, as well as a macro-micro architecture that utilizes such 6 axis robot arms and 3-4 DOF wrist mechanisms. Here, we use a novel backdrivable wrist mechanism that can achieve 90 degree pitch, yaw, and gripping motions. The obtained design and equations are also validated with experiments on a prototype that we have built. Experiment results show that an operator unilaterally controls the motion of the forceps, through a haptic interface, as desired.

2023, Physical Review E

A vector propagation scheme for describing electromagnetic nondiffracting beams (X waves͒ is introduced. In particular we show that, from the knowledge of the transverse field components on a given transverse plane and at a fixed instant, it is possible to predict the whole electric field everywhere which in particular allows us to investigate the imaging properties of nondiffracting beam. Furthermore, we show that the longitudinal field component crucially depends on the pulse velocity and that it can be neglected only if the velocity is slightly greater than c. The proposed formalism is tested by means of two examples, the vector fundamental and Gaussian X waves which admit analytical treatment. As an application of the propagation scheme, we derive in closed form the expressions for the field propagator showing that its transverse component formally coincides with one of the scalar fundamental X wave.

2023, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control

A finite element analysis and a parametric optimization of single-axis acoustic levitators are presented. The finite element method is used to simulate a levitator consisting of a Langevin ultrasonic transducer with a plane radiating surface and a plane reflector. The transducer electrical impedance, the transducer face displacement, and the acoustic radiation potential that acts on small spheres are determined by the finite element method. The numerical electrical impedance is compared with that acquired experimentally by an impedance analyzer, and the predicted displacement is compared with that obtained by a fiber-optic vibration sensor. The numerical acoustic radiation potential is verified experimentally by placing small spheres in the levitator. The same procedure is used to optimize a levitator consisting of a curved reflector and a concave-faced transducer. The numerical results show that the acoustic radiation force in the new levitator is enhanced 604 times compared with the levitator consisting of a plane transducer and a plane reflector. The optimized levitator is able to levitate 3, 2.5-mm diameter steel spheres with a power consumption of only 0.9 W.

2023, 2012 Fifth International Conference on Emerging Trends in Engineering and Technology

To realize extremely low-power consuming sensor systems, a SOHI (Silicon on Honeycomb Insulator) wafer, which has ultra-small parasitic capacitance, is proposed and an accelerometer is fabricated to demonstrate use of the technique. In case of using a low-power-consumption switched capacitor measurement circuit, parasitic capacitance decreases sensor sensitivity dramatically. The concept of the SOHI wafer is a special SOI (Silicon on Insulator) wafer with the buried SiO 2 layer replaced with a honeycomb-shaped SiO 2 thick layer (20 P Pm thick) to reduce the parasitic capacitance. In this paper, two types of SOHI wafer, which could reduce the parasitic capacitance to about 21% and 2% of typical SOI wafers, respectively are proposed. On a trial production, the structure of a prototype three-dimensional accelerometer is fabricated. By demonstrating the application of sensor fabrication, the SOHI wafer is shown as a useable material as the base substrate. Also, the ability to realize the accelerometer with low parasitic capacitance by using the SOHI wafer is demonstrated.

2023, Sensors and Actuators A: Physical

A prototype of an ultrasonic transducer based on electromechanical film (EMFi) is presented, as well as its electronic driving and receiving blocks. The electromechanical film provides a wide bandwidth response, showing enough of a level of sensitivity to allow echo-pulse measurement in the most frequency ranges for robotics applications. Emission patterns are obtained, verifying the correspondence between experimental data and the theoretical piston model. Experimental results show that the EMFi-based transducer can be used as a broadband ultrasonic transducer, allowing transmission from 20 to 200 kHz. The wide bandwidth provided by the transducer is a remarkable advantage for sensor systems using encoded ultrasonic signals with wideband modulation schemes, which require considerably more bandwidth than what conventional transducers allow. In this way, main lobes can be discriminated more easily from sidelobes and crosstalk interference can be reduced.