Thesis (M.S.)--Rochester Institute of Technology, 1994. / Typescript. Includes bibliographical references (leaf 91).

Active integrated antennas (AIAs) are divided into oscillator type AIAs, amplifier type AIAs and frequency-conversion type AIAs. The AIAs designed in this master thesis are oscillator type. Instead of using lumped component like inductors and capacitors, I use a half-wavelength antenna as resonator. In this design, antenna is also treat as a radiated loading. According to reciprocity, antenna receives the reflection signal affected by human body movement and vital sign at the same time. This behavior is regarded as a self-injection locking oscillator. In this master thesis, active antenna is used in monitoring and contacting measurement. In monitoring measurement, active antenna and subject keep their distance. Subject random body movement affects the measured result. Contacting measurement means active antenna pastes on the subject, thus there is no relative displacement between active antenna and subject. Random body movement affect iscancelled in theory. In contacting measurement design some different body motions to test the tolerance of this measurement structure, and use correlation to cancel random body movement. The sensitivity of active antenna structure is enough to detect the vocal vibration in contacting measurement.

Unmanned Aerial Vehicles (UAVs) are quite successful in maintaining steady flight operations, but propeller failure that exists causes them to experience a possible crash. The objective of this thesis project is to propose a UAV failure detection model as part of the developing framework of an autonomous emergency landing system for UAVs. Health monitoring is integrated where the quadcopter is flown for three cases of propeller faults. Vibration signals are measured during each flight, where a hardware system is designed with Arduino Uno and an Inertial Measurement Unit (IMU) sensor that contains a 3-axis accelerometer and a 3-axis gyroscope, and vibration graphs are made. Once the data is extracted, different parameters (aX, aY, aZ, gX, gY, and gZ) are selected with dimension n ∈ {1,2,3,4,5,6}, and 750 data points are chosen for the K-Means Clustering algorithm. Quadcopter Failure Detection Cluster (QFDC) plots and confusion matrices are created, and three different health states are classified as clusters – normal state, faulty state, and failure state. The parameter set gZ-aZ has the best performance metrics with an accuracy of 92.1%, which is chosen for the decision-making step that involves a Light Emitting Diode (LED) subsystem. Boundary conditions are set from the gZ-aZ QFDC plot where three LEDs turn on based on the specified health state to validate the model. The accuracies of the LED system range between 89% and 95%. Successful failure detection for UAVs would make UAVs safer and more reliable to fly with less imposed restrictions.

Submitted by PEDRO DE OLIVEIRA CONCEIÇÃO JUNIOR null (pedroliveira931@hotmail.com) on 2016-03-23T18:59:49Z No. of bitstreams: 1 dissertação_exemplar_final.pdf: 5761621 bytes, checksum: 84b8fff3fe34ccd2b227c3763843a3c9 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-23T20:05:17Z (GMT) No. of bitstreams: 1 conceicaojunior_po_me_bauru.pdf: 5761621 bytes, checksum: 84b8fff3fe34ccd2b227c3763843a3c9 (MD5) / Made available in DSpace on 2016-03-23T20:05:17Z (GMT). No. of bitstreams: 1 conceicaojunior_po_me_bauru.pdf: 5761621 bytes, checksum: 84b8fff3fe34ccd2b227c3763843a3c9 (MD5) Previous issue date: 2016-02-17 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / As cerâmicas estruturais avançadas, tais como o óxido de alumínio, nitreto de silício, alumina e a zircônia estão sendo cada vez mais utilizadas na engenharia e na medicina. No entanto, muitas destas características que fazem a cerâmica tão atrativa também dificultam a sua fabri-cação por métodos tradicionais de usinagem. Para obter a forma desejada na usinagem de ma-teriais é necessário o uso do processo de retificação. As características da retificação cerâmicas avançadas são muito diferentes das características dos metais. Portanto, é necessário efetuar outros estudos para alcançar uma compreensão mais abrangente e um melhor controle dos parâmetros. Novas alternativas para o monitoramento do processo de retificação de cerâmicas têm sido estudadas. O monitoramento por sinais de vibração é um dos métodos bem-sucedidos utilizados no processo de retificação, pois algumas características que descrevem o comportamento e a influência do processo nas peças retificadas somente são perceptíveis no estudo deste sinal. O presente trabalho tem como objetivo estudar o sinal de vibração, de for-ma a extrair características relacionadas com o acabamento de cerâmicas avançadas no pro-cesso de retificação plana. Foi utilizada uma máquina retificadora tangencial plana com rebolo diamantado e corpos de prova de cerâmica alumina. O sinal de vibração foi medido por um acelerômetro e coletado por um osciloscópio à taxa de amostragem de 2 MHz. Os ensaios foram realizados em diferentes profundidades de corte, adotando duas velocidades da peça (vw), obtendo condições de usinagem brandas às mais severas. Medições de microscopia con-focal foram realizadas após a retificação das peças com objetivo de caracterizá-las. A rugosi-dade Ra das peças usinadas foi medida em quatro pontos ao longo das mesmas, por meio de um rogosímetro portátil. O processamento digital do sinal de vibração foi realizado, aplicando ferramentas computacionais e estatísticas de análise em cada passada de usinagem, compa-rando com os valores da rugosidade medidos. A faixa de frequência entre 800 Hz e 2 kHz foi a mais interessante para o estudo, e que melhor se relacionou com a condição da cerâmica após a retificação. Foi encontrada uma correlação entre a vibração e a integridade da peça cerâmica, pois o aumento da vibração é diretamente proporcional à rugosidade em cada profundidade de corte utilizada. Infere-se que a vibração pode ser utilizada para monitorar a retificação de cerâmica, devido à sua relação com a condição das peças. / Advanced structural ceramics such as aluminum oxide, silicon, nitride, alumina and zirconia are increasingly being used in engineering and medicine. However, many of these features that make ceramics so attractive also make them difficult to manufacture by traditional machining methods. To obtain the desired shape in the machining of these materials is necessary to use grinding process. The characteristics of the grinding of advanced ceramics are very different from those of metals. Therefore, it is necessary to perform other studies to gain a broader understanding and better control of the parameters. New alternatives for monitoring of ceramic grinding process have been studied. Monitoring vibration signals is one of the successful methods used in the grinding process, as some characteristics that describe the behavior and influence the process in parts ground only are noticeable in the study of this signal. This research aims to study the vibration signal, searching for the extraction of features that best relate to the characterization of machined parts. A surface grinding machine with diamond grinding wheel and alumina ceramic workpieces was used. The vibration signal was measured by an accelerometer and collected by the oscilloscope, using 2 MHz of sample rate. Tests were conducted at different depths of cut, adopting two different feed speeds (vw), which ranged from low to severe grinding conditions. Confocal microscopy was performed after the grinded of the workpieces in order to characterized them. The surface roughness Ra of each finished workpiece was measured at four areas along its surface, using a portable roughness measurer. The vibration digital signal processing was performed by applying computational tools on each pass machining. The frequency range between 800 Hz and 2 kHz was the most interesting for the study, and which better was related to the condition of the ceramic after the grinding process. A correlation between the vibration and the integrity of the ceramic workpiece was found, because the increased vibration is directly proportional to the surface roughness at each depth of cut used. It is inferred that the vibration can be used to monitor the grinding process of ceramic because of its relationship with the condition of the workipiece.

Dans les dernières décennies, la surveillance vibratoire des machines tournantes a acquis un intérêt particulier fournissant une aide efficace pour la maintenance dans l'industrie. Aujourd'hui, de nombreuses techniques efficaces sont bien établies, ancrées sur des outils puissants offerts notamment par la théorie des processus cyclostationnaires. Cependant, toutes ces techniques reposent sur l'hypothèse d’un régime de fonctionnement (c.à.d. vitesse et/ou charge) constant ou éventuellement fluctuant d’une façon stationnaire. Malheureusement, la plupart des machines surveillées dans l'industrie opèrent sous des régimes non stationnaires afin de remplir les tâches pour lesquelles elles ont été conçues. Dans ce cas, ces techniques ne parviennent pas à analyser les signaux vibratoires produits. Ce problème a occupé la communauté scientifique dans la dernière décennie et des techniques sophistiquées de traitement du signal ont été conçues pour faire face à la variabilité du régime. Mais ces tentatives restent limitées, dispersées et généralement peu soutenues par un cadre théorique. Le principal objectif de cette thèse est de combler partiellement cette lacune sur la base d'une formalisation théorique du sujet et d’un développement systématique de nouveaux outils de traitement du signal. Dans ce travail, la non-stationnarité du régime est limitée à celle de la vitesse— c.à.d. vitesse variable et charge constante— supposée connue a priori. Afin d'atteindre cet objectif, la méthodologie adoptée consiste à étendre le cadre cyclostationnaire avec ses outils dédiés. Nous avons élaboré cette stratégie en distinguant deux types de signatures. Le premier type comprend des signaux déterministes connus comme cyclostationnaires au premier ordre. La solution proposée consiste à généraliser la classe cyclostationnaire au premier ordre à la classe cyclo-non-stationnaire au premier ordre qui comprend des signaux déterministes en vitesse variable. Le second type comprend des signaux aléatoires périodiquement corrélés connus comme cyclostationnaires au deuxième ordre. Trois visions différentes mais complémentaires ont été proposées pour traiter les variations induites par la non-stationnarité de la vitesse de fonctionnement. La première adopte une approche cyclostationnaire angle\temps, la seconde une solution basée sur l'enveloppe et la troisième une approche cyclo-non-stationnaire (au second ordre). De nombreux outils ont été conçus dont les performances ont été testées avec succès sur des signaux vibratoires réels et simulés. / In the last decades, vibration-based condition monitoring of rotating machine has gained special interest providing an efficient aid for maintenance in the industry. Nowadays, many efficient techniques are well-established, rooted on powerful tools offered in particular by the theory of cyclostationary processes. However, all these techniques rely on the assump-tion of constant— or possibly fluctuating but stationary— operating regime (i.e. speed and/or load). Unfortunately, most monitored machines used in the industry operate under nonstationary regimes in order to fulfill the task for which they have been designed. In this case, these techniques fail in analyzing the produced vibration signals. This issue, therefore, has occupied the scientific committee in the last decade and some sophisticated signal processing techniques have been conceived to deal with regime variability. But these works remain limited, dispersed and generally not supported by theoretical frameworks. The principal goal of this thesis is to partially fill in this gap on the basis of a theoretical formalization of the subject and a systematic development of new dedicated signal processing tools. In this work, the nonstationarity of the regime is confined to that of the speed— i.e. variable speed and constant load, assumed to be known a priori. In order to reach this goal, the adopted methodology consists in extending the cyclostationary framework together with its dedicated tools. We have elaborated this strategy by distinguishing two types of signatures. The first type includes deterministic waveforms known as first-order cyclostationary. The proposed solution consists in generalizing the first-order cyclostationary class to the more general first-order cyclo-non-stationary class which enfolds speed-varying deterministic signals. The second type includes random periodically-correlated waveforms known as second-order cyclostationary. Three different but complementary visions have been proposed to deal with the changes induced by the nonstationarity of the operating speed. The first one adopts an angle\time cyclostationary approach, the second one adopts an envelope-based solution and the third one adopts a (second-order) cyclo-non-stationary approach. Many tools have been conceived whose performances have been successfully tested on simulated and real vibration signals.