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Thèses sur le sujet « Ultrasonic system »

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Publié le 10 mars 2023

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1

Albuquerque, Daniel Filipe. « Ultrasonic location system ». Doctoral thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11508.

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Doutoramento em Engenharia Electrotécnica
Esta tese apresenta um sistema de localização baseado exclusivamente em ultrassons, não necessitando de recorrer a qualquer outra tecnologia. Este sistema de localização foi concebido para poder operar em ambientes onde qualquer outra tecnologia não pode ser utilizada ou o seu uso está condicionado, como são exemplo aplicações subaquáticas ou ambientes hospitalares. O sistema de localização proposto faz uso de uma rede de faróis fixos permitindo que estações móveis se localizem. Devido à necessidade de transmissão de dados e medição de distâncias foi desenvolvido um pulso de ultrassons robusto a ecos que permite realizar ambas as tarefas com sucesso. O sistema de localização permite que as estações móveis se localizem escutando apenas a informação em pulsos de ultrassons enviados pelos faróis usando para tal um algoritmo baseado em diferenças de tempo de chegada. Desta forma a privacidade dos utilizadores é garantida e o sistema torna-se completamente independente do número de utilizadores. Por forma a facilitar a implementação da rede de faróis apenas será necessário determinar manualmente a posição de alguns dos faróis, designados por faróis âncora. Estes irão permitir que os restantes faróis, completamente autónomos, se possam localizar através de um algoritmo iterativo de localização baseado na minimização de uma função de custo. Para que este sistema possa funcionar como previsto será necessário que os faróis possam sincronizar os seus relógios e medir a distância entre eles. Para tal, esta tese propõe um protocolo de sincronização de relógio que permite também obter as medidas de distância entre os faróis trocando somente três mensagens de ultrassons. Adicionalmente, o sistema de localização permite que faróis danificados possam ser substituídos sem comprometer a operabilidade da rede reduzindo a complexidade na manutenção. Para além do mencionado, foi igualmente implementado um simulador de ultrassons para ambientes fechados, o qual provou ser bastante preciso e uma ferramenta de elevado valor para simular o comportamento do sistema de localização sobre condições controladas.
This thesis presents a location system based exclusively on ultrasonic signals, without using any other technology. This location system was designed to operate in environments where the use of other technologies is not possible or the use of them is limited, such as underwater applications or hospital environments. The proposed location system uses a network of fixed beacons allowing the mobile stations to locate. Due to the necessity of data transmission and distance measurement an ultrasonic pulse robust to echoes was developed that allows to perform both tasks with success. The location system allows that mobiles locate themselves only listening to the information in the ultrasonic pulse sent by the beacons, for that an algorithm based on time difference of arrival is used. Therefore, the user privacy is guaranteed as well as the complete independence of the system number of users. To simplify the network implementation it is only necessary to manually define the position of some of the beacons, called anchor beacons. These will allow the remaining autonomous beacons to locate themselves by an iterative location algorithm based on a local cost function minimization. For this system to work properly the beacons must synchronize their clocks and measure the distance between them. Therefore, this thesis proposes a clock synchronization protocol which also allows to measure the distance between the beacons by exchanging only three ultrasonic messages. Additionally, the location system permits that damaged beacons may be replaced without compromising the network operability reducing the maintenance complexity. Additionally, a simplified ultrasonic simulator for indoor environments was developed, which has proved to be very accurate and a valuable tool to simulate the location system behavior under controlled conditions.
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2

Al, Homsi Mustafa. « Ultrasonic timer system ». Connect to this title online, 2005. http://hdl.handle.net/1811/272.

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Senior Honors Thesis (Electrical and Computer Engineering)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains 29 p.; also includes graphics (some col.). Available online via Ohio State University's Knowledge Bank.
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3

Wu, Chung Hao. « DETERMINATION OF BLADDER VOLUMES BY MICROPROCESSOR BASED ULTRASONIC SYSTEM ». Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275392.

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4

Goode, Ashley Harford. « High resolution ultrasonic imaging system ». Thesis, University of Portsmouth, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329278.

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5

Wylie, Stephen Robert. « An underwater ultrasonic imaging system ». Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266220.

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6

Redd, Justin D. « An Ultrasonic Angular Measurement System ». International Foundation for Telemetering, 1993. http://hdl.handle.net/10150/611880.

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International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada
An original design is presented for a system capable of measuring the relative angle of a flat surface using reflected ultrasonic wave pulses. No physical contact with the surface is necessary. The measurement range is from 0 to 54 degrees. Theoretical resolution is 5 minutes of arc, with actual measured resolution of approximately 20 minutes of arc. The system has performed successfully in limited flight tests, is capable of rates up to 80 angle measurements per second, and has a solid-state memory recording capacity of 24,000 bytes. The measurements are time-tagged as they are recorded and may be transferred to a personal computer at a later time over a standard RS-232 serial communications link. The system is small (approx. 6 by 4 by 1.5 inches) and uses two standard 9-volt batteries as its power source.
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7

Nadkarni, Aditya. « Reflector geometry specific modeling of an annular array based ultrasound pulse-echo system ». Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-091207-114218/.

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8

Salido, Monzú David, et Sánchez Oliver Roldán. « Robot Positioning System : Underwater Ultrasonic Measurement ». Thesis, Mälardalen University, School of Innovation, Design and Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-5817.

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This document provides a description about how the problem of the detection of thecenter of a defined geometry object was solved.This named object has been placed in an experimental environment surrounded bywater to be explored using microwaves under the water, to try to find a possibletumor. The receiver antenna is fixed in the tip of the tool of an ABB robot.Due to this working method, it was necessary to locate the center of this object tomake correctly the microwave scanning turning always around the actual center. Thiswork not only consist in give a hypothetic solution to the people who gave us theresponsibility of solve their problem, it is also to actually develop a system whichcarries out the function explained before.For the task of measuring the distance between the tip of the tool where themicrowave antenna is, ultrasonic sensors has been used, as a complement of acomplete system of communication between the sensor and finally the robot handler,using Matlab as the main controller of the whole system.One of these sensors will work out of water, measuring the zone of the object which isout of the water. In the other hand, as the researching side of the thesis, a completeultrasonic sensor will be developed to work under water, and the results obtained willbe shown as the conclusion of our investigation.The document provides a description about how the hardware and software necessaryto implement the system mentioned and some equipment more which were essentialto the final implementation was developed step by step.

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9

Thyagaraj, Suraj. « Dynamic System Analysis of 3D Ultrasonic Neuro-Navigation System ». Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1967797551&sid=3&Fmt=2&clientId=1509&RQT=309&VName=PQD.

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10

York, George W. P. « Architecture and algorithms for a fully programmable ultrasound system / ». Thesis, Connect to this title online ; UW restricted, 1999. http://hdl.handle.net/1773/5931.

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11

Godfrey, Martin William. « Optical detection system for ultrasonic surface displacements ». Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/28001.

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The work was carried out with the aim of developing an optical interferometric detection system. This was to be applied to the quantative measurement of low amplitude, high frequency surface displacements (< 1nm at several MHz). Two forms of interferometric detector are investigated. The performance and limitations in particular measurement situations are assessed for both types of interferometer. The first type of detector investigated is a miniature stabilised interferometer. The design of a stabilisation system is given, along with ways in which it can be optimised for a particular environment. The second type of detector studied is a quadrature interferometer. Various methods of processing the two channels of information from this device are discussed. The design of a new method of processing the signals is given, and its performance determined. The interferometric sensor is combined with a waveform digitiser and microcomputer to form an integrated detection system. Analysis of the waveforms obtained is performed by a system of Pascal programs developed for this purpose. The detection system is applied to tasks such as the calibration of other forms of transducer and the characterisation of artificial sources of acoustic emission. The results of experimental studies are given and the applications of such a system discussed.
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12

Wybrow, M. « An ultrasonic recognition system for flexible manufacturing ». Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381070.

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13

Ronghong, Xiao, et Wang Hai. « Car Automatic Braking System : based on original reverse warning system ». Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-11643.

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An original ultrasonic reverse warning system is a new system that can assist drivers while car is braking. It is includes ultrasonic emitter and receiver that can producing and receiving the ultrasonic waves to determine the distance between car and obstacle. But it is not good enough for the safety of cars, in this paper, we are meant to design a system that can help drivers stop the car automatically, an electronic circuit was constructed. According to this circuit we design, a signal was produced to the braking system of car based on the distance between car and obstacle for a safe braking purpose. Error is also discussed and during the experiment, the improvement for the original system has also achieved.
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14

Henderson, Harold Paulk Bevly David M. « Relative positioning of unmanned ground vehicles using ultrasonic sensors ». Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Mechanical_Engineering/Thesis/Henderson_Harold_55.pdf.

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15

Chan, Chi Kit. « An ultrasonic self-localized automated guided vehicle system / ». View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?IELM%202006%20CHAN.

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16

Mireault, Alfred Norman. « Mechanical design of an ultrasonic tomographic imaging system ». Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105689.

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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 42-44).
The paper presents the design and fabrication of a prototype for limb imaging aimed at tackling several of the issues. The design of the a US probe positioning system is intended to augment a system for motion measurement as well as a framework for the integration of motion and US data. The design of the imaging system below represents early steps towards a full-volume imaging technique for use in computer-aided prosthetic socket design.
by Alfred Norman Mireault.
S.B.
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17

Pan, Lin. « Pharmaceutical powder dispensing by ultrasonic vibration dosing system ». Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/386902/.

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Powder technology is one of the most important parts in manufacturing industry when materials applied in large quantities of solid particles. Dispensing technology for powders can significantly improve operation efficiency in manufacturing processes. The powder dispensing technologies have a broad range of applications. The powders exhibit different flow behaviours due to different physical properties. This project aims to reveal the dispensing mechanism and pharmaceutical powder flow behaviour in a designed dispensing hopper under the ultrasonic mechanical vibration, and to develop a powder dosing system to achieve the precise dispensing of pharmaceutical powders. The experimental work focuses on the dispensing device design and pharmaceutical powder dispensing tests by using ultrasonic vibration dosing system. The experimental results indicate that the ultrasonic vibration dosing system is capable of fast (less than one second) and precise (RSD < 5%) pharmaceutical powder dispensing in small-dose (milligram scale) and large-dose (gram scale). A dome-control mechanism is identified in the ultrasonic vibration dispensing process. Powder dome formed in the dispensing hopper as a “valve” of powder flow under the ultrasonic vibration. The dispensing results represent that the parameters of dispensing hopper, i.e. orifice size, hopper angle, and working voltage signal, i.e. vibration duration, are the critical factors for the powder flow rate and dosage uniformity of the dispensing. Additionally, the working voltage signal properties and mechanical vibration performance are investigated in the ultrasonic vibration dispensing device by using the digital oscilloscope and the 3D scanning vibrometer.
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18

Sebastian, Dalys. « Development of a field-deployable voice-controlled ultrasound scanner system ». Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0625104-170951/.

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19

Bergh, Charles Ferguson. « Development of an interferometric system for process monitoring ». Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19281.

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20

Ocklind, Henrik. « Driver Circuit for an Ultrasonic Motor ». Thesis, Linköpings universitet, Elektroniksystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-101013.

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To make a camera more user friendly or let it operate without an user the camera objective needs to be able to put thecamera lens in focus. This functionality requires a motor of some sort, due to its many benefits the ultrasonic motor is apreferred choice. The motor requires a driving circuit to produce the appropriate signals and this is what this thesis is about.Themain difficulty that needs to be considered is the fact that the ultrasonic motor is highly non-linear.This paper will give a brief walk through of how the ultrasonic motor works,its pros and cons and how to control it. How thedriving circuit is designed and what role the various components fills. The regulator is implemented in C-code and runs on amicro processor while the actual signal generation is done on a CPLD. The report ends with a few suggestions of how toimprove the system should the presented solution not perform at a satisfactory level.
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Faltpihl, Peter. « Ultrasonic sensing design and implementation for detecting and interacting with human beings in an AI system ». Thesis, Linköpings universitet, Fysik och elektroteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-78429.

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This thesis covers the work performed to implement a Sonar sensor solution to detect human beings on a robotic lamp. A previously available solution was evaluated, but had to be redesigned due to faulty electronics. New hardware was developed, together with software to control this hardware. A software implementation of this new Sonar sensor system was also developed, on the robotic lamp itself. The nature of this thesis was very practical, so this report will focus on describing the different design stages that were performed, together with a wide discussion about future improvements and work, in order to achieve a robotic lamp that interacts with a human in an interesting manner.
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22

Lu, Yicheng. « Real time defect detection in welds by ultrasonic means ». Thesis, Brunel University, 1992. http://bura.brunel.ac.uk/handle/2438/4966.

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A computer controlled weld quality assurance system has been developed to detect weld defects ultrasonically whilst welding is in progress. This system, including a flash analogue to digital converter and built-in memories to store sampled data, a peak characters extractor and a welding process controller, enabled welding processes to be controlled automatically and welding defects to be detected concurrently with welding. In this way, the weld quality could be satisfactorily assured if no defect was detected and the welding cost was minimised either through avoiding similar defects to occur or by stopping the welding process if repair was necessary. This work demonstrated that the high temperature field around the weld pool was the major source of difficulties and unreliabilities in defect detection during welding and, had to be taken into account in welding control by ultrasonic means. The high temperatures not only influence ultrasonic characteristic parameters which are the defect judgement and assessment criterion, but also introduce noise into signals. The signal averaging technique and statistical analysis based on B-scan data have proved their feasibility to increase 'signal to noise ratio' effectively and to judge or assess weld defects. The hardware and the software for the system is explained in this work. By using this system, real-time 'A-scan' signals on screen display, and, A-scan, B-scan or three dimensional results can be printed on paper, or stored on disks, and, as a result, weld quality could be fully computerized.
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Managuli, Ravi A. « Programmable ultrasound color flow system / ». Thesis, Connect to this title online ; UW restricted, 2000. http://hdl.handle.net/1773/6064.

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Boongsood, Wanwanut. « Design and modelling of a miniaturised ultrasonic machining system ». Thesis, University of Liverpool, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.617031.

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Ultrasonic Machining (USM) is the outstanding manufacturing process for producing complex cavities for all materials subjected to brittle fracture without the requirements of electrical/thermal conductivity or chemical reactivity. As a result, a wide range of materials can be fabricated efficiently. Even though the process benefits a variety of applications, the use of this method is not widespread because of the complexity of a large number of interacting parameters affecting the machining operation. Additionally, commercial machines available in the market tend to be rather large. In an age of micro. manufacturing and nanotechnology, as well as sustainable development, it is wasteful to machine hard and brittle materials in meso/micro scale geometries with the large equipment currently available. This research developed a miniaturised USM system. The effects of each of the different design parameters were considered and organised effectively using the Axiomatic Design approach to understanding the behaviour of a complex system. The system components were designed, modelled and then simulated with Finite Element Analysis software to characterise their responses, and were also optimised using a Design and Experiments method for a robust design. Prototypes were built and tested to validate the design. The dynamic characteristics based on prototype testing did not agree well with the computer simulation results. It was believed that this was the result of non-linearity behaviour caused by electrical impedance mismatching. Glass ceramic machining was investigated. A prediction equation of machining rates was proposed in a simple form. Through the novel miniature design, the material removal rates were comparatively superior compared with conventional systems while the size of the proposed transducer and horn assembly was reduced to half that of typical horn shapes.
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Gunarathne, Gunti P. P. « A new real-time high speed ultrasonic imaging system ». Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/32232.

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An ultrasonic imaging technique was to be developed for sizing and characterization of defects in thick sections of steel. The problems generally found with the existing techniques in such applications are low speed, inadequate image quality, large size and high cost.
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Moya, Jorge A. Salcedo. « Ultrasonic inspection of underwater piping system with thick coatings ». Connect to resource, 1994. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1260632892.

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Arya, Ishan, et Viswanaath Sundaram. « A System Study Of Ultrasonic Transceivers For Haptic Applications ». Thesis, Linköpings universitet, Elektroniska Kretsar och System, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-152346.

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We are investigating the use of ultrasound in Haptic applications. Initially abrief background of ultrasonic transducers and its characteristics were presented.Then a theoretical research was documented to understand the concepts that govern haptics. This section also discusses the algorithm adopted by various researches to implement haptics in the professional world. Then investigations were made to understand the behavior of ultrasonic transducers and conduct soft-ware simulations to obtain various results. At first simulations were conducted on Field II software. This simulations involved the creation of elements in trans-ducers, transducer’s spatial impulse responses, transducer’s impulse responsein time and frequency domain, effect of adding apodization to the transducers,pulse echo response of the transducers, beam profile variation along the focallength of the transducers. Then a Matlab based GUI was used to study the relationship between number of elements in transducers, the frequency of the input signal and duty cycle variation of the input wave. A concept of phase shift, which explains the time delay generation was also coded in Matlab.
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Lefley, Paul W. « A sensing system for two dimensional acoustical imaging ». Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328408.

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29

Jeffery, Roland. « Diagnostic ultrasound imaging and its role within musculoskeletal medicine a dissertation submitted in partial fulfilment for the degree of Master of Health Science, Auckland University of Technology, March 2003 ». Full thesis, 2003.

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30

Johnson, Charles Alan 1957. « A CONTROL SYSTEM FOR THE APPLICATION OF SCANNED, FOCUSSED ULTRASOUND IN HYPERTHERMIA CANCER THERAPY ». Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276438.

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Anhalt, Dennis Paul 1960. « MODIFICATION OF A DIAGNOSTIC ULTRASOUND UNIT'S MOVEMENT SYSTEM TO PERFORM SCANNING DURING FOCUSSED, ULTRASOUND HYPERTHERMIA ». Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/275546.

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White, John D. H. « A random signal ultrasonic test system for highly attenuating media ». Thesis, Keele University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315234.

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33

Chan, Lok-sang, et 陳樂生. « Adaptive flow detector and estimator for ultrasound high frame rate vector flow imaging ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47753043.

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Cardiovascular diseases is a leading cause of death worldwide and improvement of the corresponding screening tool is the best way to deal with this clinical problem. In this thesis we attempted to develop a framework of ultrasound high frame rate vector flow imaging (VFI) by emphasizing on the design of corresponding flow detector and flow estimator. We believe that the high temporal resolution and the complex blood flow visualization ability of high frame rate VFI enables it to be further developed as a reliable flow imaging modality for cardiological examination. In order to achieve high temporal resolution, fast data acquisition algorithm was applied in the framework. Doppler signals acquired using this acquisition algorithm have two unique characteristics comparing with conventional data acquisition algorithm: (1) widen spectral bandwidth and (2) greater clutter to blood signal ratio. These signal characteristics give rise to unique signal processing. In addition, complex blood flow pattern, which is common in cardiological examination, induces extra challenges in implementing high frame rate VFI. In this thesis, flow detector which is adaptive to different flow scenarios and high dynamic range 2D flow estimator were presented. The proposed flow detector employes K-means++ clustering algorithm to classify clutter components from acquired Doppler signals. As a performance analysis, Field II simulation studies were performed by a parabolic flow phantom (flow velocity: 10mm/s to 200mm/s; tissue motion: 10mm/s; beam-flow angle: 60?). The post-filtered Doppler power map and BCR were used as qualitative and quantitativemeasures of detectors performance. Analyzed result has indicated that, as compared with clutter downmixing detector and eigen-based detector, the proposed flow detector could classify and suppress clutter component more effectively. Results also suggested that the proposed flow detector is more adaptive to slow flow scenarios where existing flow detectors failed to distinguish between blood and clutter components. For the proposed flow estimator, it was characterized by the interpolation of speckle tracking results in Lagrangian reference frame. The estimation bias and RMS error were calculated for different flow scenarios (flow velocity: 100mm/s to 500mm/s; beam-flow angle: 15? to 60?). It was found that the proposed flow estimator provides higher dynamic range than conventional speckle tracking-based flow estimator. Nonetheless, it is also observed that the estimation variances and errors increases in slow flow scenarios. In order to demonstrate the medical potential of the proposed high frame rate VFI framework. A carotid bifurcation simulation model with realistic blood flow pattern calculated using computational fluid dynamic software was applied in the performance evaluation study. In the VFI image obtained, complex blood flow pattern was readily visualized. In contrast, conventional ultrasound flow imaging was only able to estimate axial velocity map and thus lead to many ambiguities in analyzing the complex blood flow pattern. It proved that ultrasound high frame rate VFI has the potential to be further developed into a new cardiological examination technique.
published_or_final_version
Electrical and Electronic Engineering
Master
Master of Philosophy
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34

Yang, Chuan-Hao. « A person-tracking mobile robot using an ultrasonic positioning system ». Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Dec%5FYang.pdf.

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Thesis (M.S. in Electrical and Computer Engineering)--Naval Postgraduate School, December 2005.
Thesis Advisor(s): Xiaoping Yun. Includes bibliographical references (p.49-51). Also available online.
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Robinson, Robert James. « An expert system to aid ultrasonic flaw modelling results interpretation ». Thesis, University of Strathclyde, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428856.

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Kiernan, Michael T. « An acousto-ultrasonic system for the evaluation of composite materials ». Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/76441.

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A presentation is given of an acousto-ultrasonic system for the evaluation of composite materials. First, a brief statement will be made on the acousto-ultrasonic technique and its relative worth compared to other nondestructive testing techniques as applied to composite materials. The following two chapters describe the system instrumentation and system software, respectively. Next, comments are given regarding the implementation of the system for research on graphite/epoxy laminates, with additional remarks concerning efforts to evaluate aluminum/graphite tubes with the system. This includes physical descriptions of the composite systems. Subsequently, results are presented comparing parameters and forms of presentation which can be employed to relate results. Finally, conclusions are made on the application of the acousto-ultrasonic system to nondestructive testing of composite materials, with specific results on its application to graphite/epoxy plates. More specifically, comments are made on the variation of SWF factors with azimuthal angle on the graphite/epoxy plates, the identification of specific frequency peaks, and the relationships these may have to certain modes of vibration and material properties. For example, a low frequency mode was found to vary in a manner reminiscent of Ex and to show characteristics of an extensional Lamb wave. In general, results are presented and discussed in order to show how the system can be implemented to gain physical information on composite materials, such as the property of anisotropy.
Master of Science
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37

Williams, Lauren M. « Fast Chirped Signals for a TDMA Ultrasonic Indoor Positioning System ». DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2150.

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In this paper, a new concept for ultrasonic indoor positioning based on instantaneous frequency of ultrasonic signals is presented. Nonlinear phase characteristics of ultrasonic transducers introduce a frequency deviation in ultrasonic signals. By sweeping at very fast rates, a large spike in the deviation is introduced. The artefacts observable in instantaneous frequency estimations are highly localized and present an opportunity for accurate frequency detection. In order to be useful, the artefacts need to take place within the pulse and have sufficient magnitude for accurate processing. The system consists of a transducer transmitter and receiver pair, which have a center frequency of 40kHz and a bandwidth of 460Hz. In order to incorporate more transmitters, a time-division multiple access (TDMA) scheme is applied to ensure orthogonality of signals. The concept includes four ultrasonic transmitters and a single receiver, which can uniquely identify each transmitter by a distinct signal sweep. Linear chirp signals are used to form narrow pulses and ensure no interference in the TDMA scheme. The received signal is amplified and passed through a phase-locked loop (PLL) to detect the chirp signals. Accurate instantaneous frequency detection can be done on the voltage-controlled oscillator (VCO) of the PLL, which has a narrower bandwidth than the overall signal sweep. The instantaneous frequency estimation methods are largely explored in this work and consider two methods: the Hilbert transform and a zero-crossings method. This work highlights some of the advantages and disadvantages of both methods. Time of flight (ToF) in this system can ultimately be obtained by considering the instantaneous frequency estimations and the time for one particular frequency to be transmitted and received.
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38

Karuturi, Hemanth Surya, et Megha Sanjeev Reddy Karri. « Raspberry Pi Based IoT System for Bats Detection at Wind Farms ». Thesis, Blekinge Tekniska Högskola, Institutionen för matematik och naturvetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20899.

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Context: Large numbers of bats are killed by collisions with wind turbines and there is at present no accepted method of reducing or preventing this mortality. We designed a system, which detects and records any bats’ activity in and around the surroundings of wind turbines. The system can help to study bats by identifying the species that are present in that particular locality. Objectives: The main objective of this thesis is to design an ultrasound-based IoT system, which detects the bats to prevent them from clashing with wind turbines. The design is based on a study of bats’ behaviors. Methods: The system has been developed using User-Driven Design, UDD, approach. The required functionalities have been embedded into IoT based system. An ultrasonic technology along with other sensors are used. The sensors are intended to activate monitoring during favorable conditions for bat activity. Results: A model of a system has been developed. The model was implemented into a prototype. Recorded bats’ activities are uploaded to a server by employing a suitable app, which informs the user about the activities of bats' various sub-species. Conclusions: A surveillance for bats approaching the wind farms within 80 m has been developed. The monitoring system is activated when the weather conditions are favorable for bat activities.
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39

Johnson, Wesley Byron. « Design and Testing of a Laboratory Ultrasonic Data Acquisition System for Tomography ». Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/30938.

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Geophysical tomography allows for the measurement of stress-induced density changes inside of a rock mass or sample by non-invasive means. Tomography is a non-destructive testing method by which sensors are placed around a sample and energy is introduced into the sample at one sensor while the other sensors receive the energy. This process is repeated around the sample to obtain the desired resolution. The received information is converted by a mathematical transform to obtain a tomogram. This tomogram shows a pixelated distribution of the density within the sample. Each pixel represents an average value at that point. The project discussed in this paper takes the principle of ultrasonic tomography and applies it to geomechanics. A new instrumentation system was designed to allow rapid data collection through varying sample geometries and rock types with a low initial investment. The system is composed of sensors, an ultrasonic pulser, a source switchbox, and analog to digital converters; it is tied together using a LabVIEW virtual instrument. LabVIEW is a graphical development environment for creating test, measurement, and other control applications. Using LabVIEW, virtual instruments (VIs) are created to control or measure a process. In this application LabVIEW was used to create a virtual instrument that was automated to collect the data required to construct a tomogram. Experiments were conducted to calibrate and validate the system for ultrasonic velocity determination and stress redistribution tomography. Calibration was conducted using polymethylmethacrylate (PMMA or Plexiglas) plates. Uniaxial loads were placed on limestone and sandstone samples. The stress-induced density contrasts were then imaged using the acquisition system. The resolution and accuracy of the system is described. The acquisition system presented is a low-cost solution to laboratory geophysical tomography. The ultimate goal of the project is to further the ability to non-invasively image relative stress redistribution in a rock mass, thereby improving the engineerâ s ability to predict failure.
Master of Science
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40

Lopez-Sanchez, Ana Lilia. « Ultrasonic system models and measurements / ». 2005.

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41

Chang, Chi-Lon, et 張慶龍. « Ultrasonic Motor Positioning Assistive System ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/24047564978262569459.

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碩士
國立成功大學
電機工程學系碩博士班
94
In recent few years, the traffic and the fortuitous accidents result in paralytic events frequently, these disabled persons urgently need assistive device to support their daily activities. The purpose of this thesis is to use ultrasonic sensor components as a phase shift detector to help disabled persons who want to use mouth -control Text Input system as the input device of the computer by themselves. They can only slightly turn their head and utilize ultrasonic components to detect their shifting behavior, it will produce a signal to microprocessor to control the DC motor with accurating precision positioning by coding. DC motor controls a robot arm to bring the mouth-control switch back to the disabled person’s mouth when the switch leaves his or her mouth. As such, they can not only use computer conveniently by themselves but also reduce the dependence on families in daily activities.
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42

Ho, Tsuo-Ming, et 何祚明. « High Frequency Ultrasonic Imaging System ». Thesis, 2002. http://ndltd.ncl.edu.tw/handle/57645816658374046599.

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碩士
國立臺灣大學
電機工程學研究所
90
Ultrasound imaging is a well-established imaging modality that provides diagnostic information in the form of cross-sectional images of soft tissue. However, for many clinical applications involving subtle tissue structure, the resolution of the conventional ultrasound imaging system that operates between 2 and 10 MHz is inadequate. Recent developments have taken advantage of the fact that resolution increases linearly with frequency. In this paper, a high frequency ultrasonic imaging system with high resolution and multi-format imaging has been developed for noninvasive imaging of small scale superficial structures such as the skin, the anterior chamber of the eye, and mouse embryos for studies in developmental biology. The major design problem concerning medical high frequency ultrasonic imaging systems is caused by the strong attenuation of the tissue, which limits the maximum depth of penetration and the achievable signal to noise ratio (SNR). In this paper, the coded excitation and pulse compression techniques, which can increase the average transmitted power, are utilized to increase both the depth of penetration and SNR. In addition, since array transducers with dynamic focusing are not available for high frequency system, the image quality is significantly deteriorated in the out-of-focused region. Hence, a filter-based synthetic aperture focusing technique is employed here to improve the degraded beam quality. Such a filter is designed in the LMSE sense and is also known as the optimal filter. Moreover, depth scan technique is also applied to increase the depth of field for this high frequency system. The experimental results demonstrate that the 50 MHz ultrasonic imaging system developed in this paper has resolution on the order of 100 mm and a 55-dB SNR. Implementation issues of optimal filter to increase the depth of field for a single crystal transducer system are also discussed. Based on the high frequency ultrasonic imaging system constructed in this paper, advanced high frequency ultrasound research on high frequency tissue harmonics, perfusion blood estimation and contrast agent characteristics could be performed. In addition, combined with other medical imaging systems, this system might be able to provide much more valuable information on clinical diagnostics and biomedical research in the future.
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43

Chang, Bo-Wun, et 張博文. « Deviation analysis of ultrasonic positioning system ». Thesis, 2006. http://ndltd.ncl.edu.tw/handle/81220140568927441883.

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碩士
清雲科技大學
電子工程研究所
94
An ultrasonic positioning system is introduced in this thesis. The system has three sensors. These sensors are located at different apex of the equilateral triangle. An ultrasonic emitter is arranged at center of the equilateral triangle. With the emitter and the sensors, obstacles in front of the blind can be detected by using time-of-flight of the ultrasonic wave. Because amplitude recession, temperature and humidity can influence the measurement accuracy, deviation analysis is very important for the ultrasonic positioning system. An area of ±15°, 1 meter to 2 meters in front of the sensors has been evaluated. Some simulation results and conclusions are also given in this thesis.
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Yeh, Yung-An, et 葉永安. « Circuit Design of Ultrasonic Guiding System ». Thesis, 2010. http://ndltd.ncl.edu.tw/handle/10242727409915758432.

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碩士
清雲科技大學
電機工程研究所
98
A circuit design of ultrasound guiding system is introduced. The system has one ultrasonic emitter and three sensors. These sensors are located at different apex of an equilateral triangle. The emitter is arranged at center of the equilateral triangle. With the emitter and the sensors, obstacles in front of the blind can be detected by using time-of-flight of the ultrasonic wave. Because amplitude recession, temperature and humidity may influence the measurement accuracy, a small area of 20 to 140 centimeters in front of the sensors has been considered and evaluated. Some experiment results and conclusions are also given in this thesis.
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Kao, Kuang-Chien, et 高光前. « Automatic Ultrasonic System for Flaw Inspection ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/49636931409597561039.

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碩士
國立屏東商業技術學院
資訊管理系
92
Ultrasound has many important applications in nondestructive testing. Since ultrasonic signal can penetrate many materials, it is widely used for detection of flaws. The evaluations of welding are the main purpose of this paper. The use of ultrasound is limited by several interferences, such as geometric inter-face, coarse grain, mode conversion and ringing. It will be practically difficult to perform evaluation if the originally received ultrasonic signal is used directly as false judgment may be obtained. This paper will use the methods of signal processing and wavelet transform to reject noisy signal and detect the position and relative information of flaws. Owing to effect that the sound beam will diverge in far field, the flaw information will be distorted in 2-D or 3-D ultrasonic images. Synthetic aperture focusing technique (SAFT) uses the methods similar to sensor fusion to reduce the distortion and increase the accuracy for evaluation. The appraisal of the size of the flaw utilizes the distance between the flaw and transducer. The size of flaw can then be measured according to a proportionally transfer function. We also performed measurement on various types of side-drilled holes and cracks. Simulations show that our method provides very effective results.
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46

Chao-HungTseng et 曾兆弘. « Design of ultrasonic distance measurement system ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/81133627966694429428.

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碩士
中華大學
機械與航太工程研究所
93
The advantages of the Ultrasonic Ranger Finder(URF) are simple hardware, easy to obtain the components and the components are inexpensive. Our researches are to investigate the performances of the single frequency ultrasonic range finder to the best accuracy for high precision measurement. The time of flight ranging algorithm is the typical method for the range measure. But in this TOF method, the specific returned signal must have sufficient amplitude and the pulse shape, otherwise, there will have accuracy errors. We have used the software as well to compensate the errors and to increase to a satisfactory accuracy of measurement.
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Tien, Y. F., et 田亦凡. « High Speed Ultrasonic Image Inspection System ». Thesis, 2001. http://ndltd.ncl.edu.tw/handle/49369719312725345137.

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碩士
國立成功大學
機械工程學系
89
Ultrasound is a very important tool which has many applications in biological, medical and engineering practices. One can use ultrasound to measure the wave velocity and find the physical properties including Young’s modulus, shear modulus, etc. Ultrasound is also used for detecting cracks and voids in materials in a non-destructive way, so that the defects can be found out and characterized in advance. This thesis introduce a ultrasonic scanning system which consists of a transducer, a peak detector, a water tank, a motorized X-Y axis scanning frame, a servo-motion control card, and a personal computer. The transducer is used to excite and receive ultrasonic waves at a frequency of 5 MHz. The sample is placed in a tank filled with water, which couples the ultrasound transmitted by the transducer to the sample under investigation. The X-Y axis motors are controlled by a PC-based motion control card. An ultrasonic image of the sample, which contains useful material information, can be obtained by an analog-digital data acquisition card which is also PC-based. The goal of this work is to promote the scanning speed and the performance of the ultrasound image scanning system so that it can meet the industrial standards and even compete with existing commercial products. In this thesis, Microsoft Visual C++ 6.0 has been chosen to develop the software and all other functions. The reason is that it has the properties of both high-level and low-level programming capability, and it is also an Object-Oriented Programming language which is easy to develop in a Windows system. Furthermore, Visual C++ program develop tool are widely used in industry.
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Huang, Yu-Ya, et 黃郁雅. « Velocity Measurement by Ultrasonic Doppler System ». Thesis, 2012. http://ndltd.ncl.edu.tw/handle/96605762763682191332.

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碩士
國立臺灣大學
工程科學及海洋工程學研究所
100
The velocity measurement is an important item in various engineering field. Ultrasound is non-invasive, non- destroyed, high security, and attenuated lower than optical methods, so it is frequently applied to underwater measurement. This work establishes a pulsed ultrasonic Doppler system, which is based on scattering and Doppler-effect, consists of burst signal generator, power amplifier, transducer, pre- amplifier, oscilloscope, and digital signal processing software, Matlab. The measurement was conducted in a cavitation tank of uniform velocity distribution and the measured velocities were compared with a calibrated Pitot probe. By extracting the Doppler frequency shift, six flow velocities with three ultrasound projection angles were measured and the results of both velocities and flow directions matched very well with those of Pittot probe.
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Chi-TseKuo et 郭奇澤. « An FPGA-Based Ultrasonic Image Scanning System and Non-immersed Ultrasonic Inspection ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/94422215381460325358.

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碩士
國立成功大學
機械工程學系
102
This study constructs a Field Programmable Gate Array (FPGA) based non-destructive inspection system and a non-immersion ultrasonic scanning device. The inspection system exploits the high integration and flexibility of FPGA for real-time motion monitoring, acoustic trigger, data acquisition and signal analysis and reduces the host system loading by sending shortest data. Furthermore a concise concept of non-immersion ultrasonic scanning device is designed for non-destructive testing specimen that is apt to rust. This scanning system realizes a multiple profile and flatness correction ultrasonic signal measurement with FPGA chip. The FPGA programs use 100 multiple gates to split signal for realizing multiple profiles and two-step analysis to fix the sample’s flatness problem. The available scanning modes include A-scan, B-scan, P-scan, C-scan, X-scan, G-scan, and S-scan. A horizontal deviation less than 0.23 mm or 5.2 degree can be fixed by the surface detection function in the FPGA. The maximum scanning speed reaches 2000 mm/s. The vertical and horizontal scanning resolution of simple specimen is 3 μm and 20 μm respectively and the horizontal scanning resolution of complex large curvature specimen is 50 μm. The nominal sampling rate is 22 kHz and the average sampling rate is 8 kHz. Its performance is compatible with some commercial models of ultrasonic inspection systems. For non-immersion scanning, a special device is developed in order to couple the specimen surface with very little water for scanning over a 220 mm × 220 mm large area. The results of non-immersion and immersion resolution and image quality are quite the same. However, if the specimen is not well leveled over a wide range, the signals will show vertical deviations.
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Jhang, You-Jyun, et 張宥駿. « Hardware of Ultrasonic Doppler System for Velocity Measurement and Ultrasonic Measurment System for Concentration of Suspended Sediment ». Thesis, 2014. http://ndltd.ncl.edu.tw/handle/18263379973222199937.

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碩士
國立臺灣大學
工程科學及海洋工程學研究所
102
Suspension systems are used extensively in hydrology, biochemistry, and the food industry. The Ultrasonic for concentration measurement has several advantages, such as its non-intrusive, no moving parts. It can penetrate the non-transparent fluid, paring with a complete set of calibration and rating curve in the laboratory. It will be able to overcome all kinds of particle size, temperature, water, the error caused by the bubble fluid. This systems will be extensively used in hydrology, biochemistry, and the food industry in the future. The method for the measurement is to detect the energy attenuation between a transmitter-receiver pair transducer. To increase the accuracy of data analysis, received electric signals are compressed and enveloped as square waves by a logarithmic amplifier AD8310 to avoid the noise effect. The novel signal processing method is evaluated by experimental data in a laboratory environment to provide linear results for kaolin (0 ~ 100,000 ppm) and slurry samples (0 ~ 390,000 ppm) from the Tseng Wen reservoir in Taiwan. The velocity measurement is an important item in various engineering field. This work establishes a pulsed ultrasonic Doppler system, which is based on scattering and Doppler-effect, consists of power amplifier, transducer , oscilloscope, and digital signal processing software Matlab. And with self-designed circuits, such as transmitter circuit, receive isolation circuit and pre-amplifier second order band-pass filter. This study is conducted using transducer from four directions to output sound beams generated via converse piezoelectric effect, receiving echoes, and obtaining the relative speed of measurement system and water flows by means of signal processing and calculation of Doppler shift.
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