12 research outputs found

    INPUT SHAPING CONTROL TO REDUCE RESIDUAL VIBRATION OF A FLEXIBLE BEAM

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    In this paper, three control algorithms based on input shaping method are developed to suppress the residual vibration of a flexible beam. The flexible beam is modeled as an under-damped system. Three input shapers, ZV, ZVD, and ZVDD, are used to control the flexible beam. The three control algorithms are implemented by using the Mechatrolink-III motion system. The experiments are performed to verify the effectiveness of the three control algorithms

    Design and development of an industrial network laboratory

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    This paper presents the first developments of an industrial network laboratory prototype. In the Automation Laboratory several kits have been implemented for local and remote control tests. The approach includes the design and implementation of an industrial network where the common communications protocols can be tested: the Automation Network Locker (ANL). To facilitate the monitoring and control of the network, WALC (Web Assisted Laboratory for Control Engineering on-line Education) interface platform was developed. This allows the remote monitoring and control of the pedagogic kits to complement the teaching/learning automation to undergraduate engineering students. The security of network access is also taken into account in order to limit and control the number of users that can access it. An on-line questionnaire accessed at the end of each semester, allows an actualization and to follow the students’ feedbackFundação para a Ciência e a Tecnologia (FCT

    Desarrollo e implantación de un sistema de medida de antenas en cámara anecoica

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    En esta tesis se presenta el desarrollo e implantación de una instalación de medida para caracterizar el patrón de radiación de determinadas antenas. Este tipo de instalación, denominada cámara anecoica, está formada por un recinto cerrado con un recubrimiento metálico y que junto con el material absorbente adherido a paredes, techo y suelo, permite realizar mediciones en ausencia de interferencias electromagnéticas externas así como de contribuciones de la propia antena provocadas por reflexiones. Aparte de los elementos mencionados, la instalación está compuesta por otros elementos de carácter electromecánico y electromagnético, y aunque hoy día existe multitud de información sobre cada uno de estos elementos, no es fácil encontrar información sobre el proceso de diseǫ, desarrollo y puesta a punto de este tipo de instalaciones en su conjunto. El presente trabajo pretende realizar un estudio completo de cada uno de los elementos por los que está formada la cámara anecoica, así como desarrollar nuevas técnicas para el proceso de movimiento, control y medición electromagnética de una antena. Para ello se ha hecho uso de la tecnología Trajexia de Omron, mediante la cual han sido desarrollados diferentes tipos de movimientos con los que se permiten realizar exploraciones en una superficie plana, cilíndrica y esférica. El diseǫ de la cámara permite realizar mediciones en campo cercano para los sistemas de exploración plano y cilíndrico, y campo cercano y lejano de hasta 5 metros para el sistema de exploración esférico. También han sido implementados algoritmos de corrección de la posición para los diferentes ejes de movimiento que han permitido mejorar de forma considerable la precisión del sistema. Las técnicas implementadas permiten realizar mediciones electromagnéticas de antenas hasta 40 GHz. Para facilitar la interacción entre el usuario y el sistema se ha diseądo una interfaz gráfica que actúa como nexo de unión entre todos los elementos instalados, permitiendo gestionar el proceso de una medida de una manera sencilla y precisa. La interfaz ha sido desarrollada con el programa VEE de Agilent Technologies, y que entre otras tareas se encarga de virtualizar los instrumentos, configurar la medida que se pretende realizar, sincronizar todos los elementos del sistema y gestionar las mediciones de los instrumentos implantados. Para completar la instalación ha sido implementado un software de post-procesado basado en métodos numéricos que procesan los campos medidos en situación de campo cercano y obtienen la transformación a campo lejano. Para llevar a cabo estos procesos matemáticos se ha hecho uso de los lenguajes de programación Matlab y Fortran, que facilitan el trabajo a la hora de trabajar con grandes matrices de datos. Los algoritmos son ejecutados a través de una interfaz gráfica desarrollada en Java y que gestiona la visualización de resultados. Utilizando la interfaz es posible visualizar el patrón de radiación de la antena, directividad, ganancia y parámetros-S entre otros. La instalación de medida ha sido verificada con múltiples medidas de una gran variedad de antenas y con diferentes frecuencias de operación. Los resultados han sido comparados con resultados obtenidos de simulaciones electromagnéticas y con los obtenidos de otras cámaras anecoicas confirmando el correcto funcionamiento de la instalación. Previa presentación de este trabajo, la instalación ha formado parte de un gran proyecto a nivel nacional en la que se ha tenido que caracterizar el patrón de radiación de la antena de un satélite de observación de la Tierra, demostrando que la instalación desarrollada e implantada se encuentra en situación de llevar a cabo mediciones para los proyectos más sofisticados

    From Open CNC systems to Cyber-Physical machine tools: a case study

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    The aim of next-generation Computer Numerical Control (CNC) is shifting from an open architecture, which has better flexibility, adaptability, versatility and expansibility, to a cyber-physical model, which offers real-time monitoring and control of the machining processes. This paper introduces a real case study to demonstrate such tendency from Open CNC systems to Cyber-Physical Machine Tools (CPMT) based on a low-power embedded platform. Firstly, a new open CNC architecture is presented, which is able to achieve high-precision, high-efficiency, and low-power consumption. Secondly, the open CNC architecture is extended to a CPMT by using Wireless Sensor Networks (WSN), where WSN is utilized to enable monitor and control the machining processes, and the integrated development platform is termed as CPMT. Finally, a case of health monitoring system for CPMT is designed and its system testing is carried out

    Real-time condition monitoring of Ethernet based automation networks

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    Automaatiojärjestelmien nopeasti kasvava tiedonsiirtotarve luo yhä suurempia haasteita automaation tietoverkoille sekä niiden ylläpidolle. Näiden haasteiden vähentämiseksi verkkoa tulee valvoa sekä hallita verkkoympäristön vaatimalla laajuudella. Tämän tutkimuksen painopiste on verkonvalvonnassa ja sen soveltamisessa automaatiojärjestelmien Ethernet-pohjaisiin tietoliikenneverkkoihin. Verkonvalvonnan tulee olla jokapäiväinen työkalu yrityksen verkkoympäristön toiminnan tukena. Valvontajärjestelmän avulla varmistetaan verkon oikea toiminta sekä vähennetään suunnittelemattomia tuotantoa häiritseviä katkoksia. Tässä diplomityössä tutkittiin kirjallisuusselvityksen avulla verkonvalvonnan menetelmiä ja käytäntöjä perinteisen informaatioteknologian näkökulmasta. Työssä pohdittiin näiden menetelmien ja käytäntöjen soveltuvuutta Ethernet-pohjaisiin automaatioverkkoihin. Aluksi perehdyttiin automaatioverkkoihin ja näiden verkkojen vaatimuksiin. Vaatimusten pohjalta ymmärrettiin verkon toimintaan vaikuttavat tekijät sekä toiminnan varmistamisen kriittisyys. Tiedonsiirtoprotokollien standardiviitemallien avulla luotiin teoriapohja automaatioverkon profiileille sekä verkonvalvontaan soveltuville protokollille. Tutkimuksessa perehdyttiin myös virtausteknologioihin sekä näiden teknologioiden hyödyntämiseen automaation verkonvalvonnan tarkoituksissa. Verkonhallinnan viitemallit tarjoavat ohjeistuksen verkonhallinnan ja -valvonnan osa-alueiden toteuttamiseksi sekä liittämiseksi osaksi yrityksen jokapäiväistä liiketoimintaa. Tämän diplomityön tavoitteena oli toteuttaa teoriapohjan perusteella verkonvalvontakokokonaisuus, joka soveltuu työn tilaajan tarpeisiin. Verkonvalvontakokonaisuus toteutettiin avoimen lähdekoodin sovelluksilla. Näiden sovellusten avulla vastattiin vikojenvalvonnan sekä suorituskyvynvalvonnan osa-alueiden vaatimuksiin. Verkonvalvontajärjestelmän avulla voidaan vähentää verkon vikaantumista ja lyhentää vianselvityksen kestoa. Valvontajärjestelmän avulla toteutettiin verkon rakenteen visualisointi sekä lisättiin verkon läpinäkyvyyttä verkonylläpitäjälle

    Real-time condition monitoring of Ethernet based automation networks

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    Automaatiojärjestelmien nopeasti kasvava tiedonsiirtotarve luo yhä suurempia haasteita automaation tietoverkoille sekä niiden ylläpidolle. Näiden haasteiden vähentämiseksi verkkoa tulee valvoa sekä hallita verkkoympäristön vaatimalla laajuudella. Tämän tutkimuksen painopiste on verkonvalvonnassa ja sen soveltamisessa automaatiojärjestelmien Ethernet-pohjaisiin tietoliikenneverkkoihin. Verkonvalvonnan tulee olla jokapäiväinen työkalu yrityksen verkkoympäristön toiminnan tukena. Valvontajärjestelmän avulla varmistetaan verkon oikea toiminta sekä vähennetään suunnittelemattomia tuotantoa häiritseviä katkoksia. Tässä diplomityössä tutkittiin kirjallisuusselvityksen avulla verkonvalvonnan menetelmiä ja käytäntöjä perinteisen informaatioteknologian näkökulmasta. Työssä pohdittiin näiden menetelmien ja käytäntöjen soveltuvuutta Ethernet-pohjaisiin automaatioverkkoihin. Aluksi perehdyttiin automaatioverkkoihin ja näiden verkkojen vaatimuksiin. Vaatimusten pohjalta ymmärrettiin verkon toimintaan vaikuttavat tekijät sekä toiminnan varmistamisen kriittisyys. Tiedonsiirtoprotokollien standardiviitemallien avulla luotiin teoriapohja automaatioverkon profiileille sekä verkonvalvontaan soveltuville protokollille. Tutkimuksessa perehdyttiin myös virtausteknologioihin sekä näiden teknologioiden hyödyntämiseen automaation verkonvalvonnan tarkoituksissa. Verkonhallinnan viitemallit tarjoavat ohjeistuksen verkonhallinnan ja -valvonnan osa-alueiden toteuttamiseksi sekä liittämiseksi osaksi yrityksen jokapäiväistä liiketoimintaa. Tämän diplomityön tavoitteena oli toteuttaa teoriapohjan perusteella verkonvalvontakokokonaisuus, joka soveltuu työn tilaajan tarpeisiin. Verkonvalvontakokonaisuus toteutettiin avoimen lähdekoodin sovelluksilla. Näiden sovellusten avulla vastattiin vikojenvalvonnan sekä suorituskyvynvalvonnan osa-alueiden vaatimuksiin. Verkonvalvontajärjestelmän avulla voidaan vähentää verkon vikaantumista ja lyhentää vianselvityksen kestoa. Valvontajärjestelmän avulla toteutettiin verkon rakenteen visualisointi sekä lisättiin verkon läpinäkyvyyttä verkonylläpitäjälle

    Matraquilhos inclusivos : controlo inteligente de eixos

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    Mestrado em Engenharia Eletrónica e InformáticaExame público realizado em 14 de junho de 2023Nos dias de hoje, apesar de haver uma crescente consciencialização para uma melhor adaptação dos meios físicos de modo a permitir a interação de indivíduos com necessidades Específicas, existe ainda uma discrepância considerável na quantidade e qualidade de tarefas ou eventos em que podem participar. Uma atividade aparentemente simples como um jogo de matraquilhos fica vedada a indivíduos com Necessidades Específicas. Contudo, estas dificuldades podem ser atenuadas com a ajuda de meios eletrónicos e informáticos. Para ajudar estas pessoas em contexto terapêutico, o ponto central da dissertação é uma Mesa de Matraquilhos robotizada já presente na Universidade, na qual se definiu que o movimento autónomo dos eixos da mesa com a possibilidade de recolha dos dados para futura análise é o objetivo do projeto. Pretende-se que a base de dados seja boa o suficiente para que os seus dados sirvam para futuras análises de, por exemplo, terapias. Foram estudados os componentes da Mesa de Matraquilhos e projetaram-se novos comandos do tipo ‘joystick’, para permitir um maior controlo dos eixos por parte dos jogadores. A Mesa de Matraquilhos sofreu uma atualização para permitir que os eixos fossem autónomos. Os joysticks criados mereceram a aprovação de terapeutas. Utilizou-se um sistema de aquisição de dados que permitiu recolher os dados dos sensores da mesa. A estes dados aplicou-se um método de Inteligência Artificial (Naïve Bayes gaussiano). O campo de jogo foi dividido em áreas por onde a bola se move e passou-se essa representação para as memórias dos autómatos. Depois, colocaram-se os eixos a mover autonomamente. Os dados recolhidos da mesa ficam associados a um jogador. Caso se pretenda, os dados podem ser acrescentados ao ficheiro para se aplicar novamente o método de Inteligência Artificial, tornando mais robustas as decisões tomadas. O método de Inteligência Artificial acabou por prever 99,5% dos movimentos dos eixos e 96,7% dos estados de remate, culminando num acerto total de 96,2%, sendo considerado este um valor aceitável de acertos. O método de captação dos dados consegue exibir uma taxa de atualização de 50 ms sendo que o único fator negativo é o tamanho das áreas do campo para detetar a bola. Os resultados alcançados foram positivos e mostram que, enquanto prova de conceito, épossível utilizar uma Mesa de Matraquilhos robotizada para recolher informação sobre mobilidade e capacidade cognitiva, motivando a participação dos intervenientes utilizando aspetos lúdicos e inclusivos. Palavras-chave: Automação, Base de Dados, Aprendizagem Automática, Matraquilhos RobotizadosNowadays, although there is a growing awareness for a better adaptation of physical environments to allow the interaction of individuals with Special Needs, there is still a considerable discrepancy in the quantity and quality of tasks or events in which they can participate. A seemingly simple activity like a game of foosball is closed to individuals with Special Needs. However, these difficulties can be alleviated with the help of electronic and computer aids. To help these people in a therapeutic context, the central point of the dissertation is a robotic table soccer table already present at the University, in which it was defined that the autonomous movement of the axes of the table with the possibility of data collection for future analysis is the goal of the project. It is intended that the database be good enough for its data to be used for future analysis of, for example, therapies. The components of the Foosball Table were studied and new joystick type controls were designed to allow for greater control of the axes by the players. The table soccer table was upgraded to allow the axes to be autonomous. The joysticks created met with the approval of therapists. A data acquisition system was used to collect data from the table's sensors. An Artificial Intelligence method (Gaussian Naïve Bayes) was applied to this data. The playing field was divided into areas where the ball moves and this representation was passed to the automata's memories. Then, the axes were placed to move autonomously. The data collected from the table is associated with a player. If desired, the data can be added to the file to apply the Artificial Intelligence method again, making the decisions made more robust. The Artificial Intelligence method ended up predicting 99.5% of the axis movements and 96.7% of the shot states, culminating in a total accuracy of 96.2%, being considered an acceptable value of accuracy. The data capture method is able to display a 50 ms update rate, and the only negative factor is the size of the field areas to detect the ball. The results achieved were positive and show that, as a proof of concept, it is possible to use a robotic foosball table to collect information on mobility and cognitive ability, motivating the participation of the participants using playful and inclusive aspects. Keywords: Automation, Database, Machine Learning, Robotic Foosbal

    Design and fabrication of a system for the additive manufacturing of transparent glass

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    Despite glass\u27 prevalence in the scientific and engineering community, very little research has been conducted attempting to additively manufacture (AM) glass. Even less research has been done on optically transparent glass. Glass’ material properties make it ineligible for most AM processes if the end result is to be transparent. Even small gas inclusions can cause large amounts of scattering. Additively manufacturing transparent glass brings the advantages found in other AM processes with the added benefit of having optical properties better than those found in polymers. Additively manufacturing glass also allows the optical properties of transparent parts to vary arbitrarily. This thesis presents the design, manufacture, and control of a system to AM transparent glass. The system feeds glass wires, which are opaque in the near infrared, into a melt pool maintained by a CO₂ laser (10.6μm). The laser beam and melt pool remained fixed as the AM part is moved using a motion stage as the glass is deposited layer-by-layer. The stages are controlled using a PID controller, and the wire feeders are controlled using a PD controller. A spring damper model is also presented to model the deposition process along the feed direction, and perpendicular to the feed direction for control purposes. The Glass AM process is able to create morphologically accurate glass pieces more efficiently, and with fewer filament breakages than the prototype system. The glass produced with this system has optical properties as good as cast glass. The Glass AM system is also expandable and interchangeable so that more subsystems can be added and changed with minimal redesign --Abstract, page iii

    The Dynamics of Ventilated Partial Cavities over a Wide Range of Reynolds Numbers and Quantitative 2D X-ray Densitometry for Multiphase Flow.

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    Ventilated partial cavity drag reduction is a technique that could potentially enable reduction of a ship's frictional drag, leading to a 5 to 20% net fuel savings, and thus providing economic and environmental benefits. Ventilated partial cavity drag reduction experiments were conducted using two geometrically similar experimental setups. First, experiments were performed at the world's largest re-circulating water channel, the U.S. Navy's Large Cavitation Channel (LCC), at Reynolds numbers to 80 million. For these experiments the LCC was adapted to allow free surface testing, which in itself was a major effort. The effect of the cavity closure geometry, and the cavity's robustness in the presence of global flow perturbations mimicking the effect of ambient waves were studied. Next, the experiments were reproduced at 1:14th size scale at Reynolds numbers of the order of one million, and in these small scale experiments the effect of Weber number was also investigated by reducing the surface tension by a factor of two. Results from these two sets of experiments were compared, and a potential scaling of required ventilation gas flux discussed. In addition the energy economics of the partial cavity drag reduction technique were analyzed. We can note that for partial cavities, the air entrainment is dominated by the cavity closure dynamics. To gain a better understanding of these dynamics, knowing the void fraction distribution, both spatially and temporally, would be very useful. In the cavity's closure region, as well as in most cavitating flows, any intrusive probe would perturb the flow greatly. X-ray densitometry offers a way to obtain a two dimensional time-resolved projection of the void fraction distribution, and a quantitative measure of the void fraction along the beam paths. An x-ray densitometry system was developed for use with a pre-existing cavitation tunnel. The limitations of the x-ray system were investigated, methods to contend with the imaging artifacts found, and the measured void fraction profiles compared against those obtained employing dual fiber optical probes and high speed video.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91443/1/smakihar_1.pd
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