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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A study of self-tuning controllers and electrohydraulic cylinder drives

Finney, J. M. January 1982 (has links)
No description available.
2

Modelagem de um servomecanismo para acionamento da placa swashplate de uma bomba de pistões axiais de vazão variável

Bazarin, Felipe Yamane [UNESP] 20 December 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-20Bitstream added on 2014-06-13T20:18:23Z : No. of bitstreams: 1 bazarin_fy_me_guara.pdf: 3642303 bytes, checksum: 551fe75829a9029b155d49f78fdfa61e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O desenvolvimento do projeto e a manufatura de servocomandos hidráulicos é privilégio de poucas empresas no mundo. Uma pesquisa para obter informações sobre o projeto deste tipo de equipamento revelou pouquíssimas informações técnicas sobre este assunto. Talvez pela falta de uma literatura específica sobre o projeto deste tipo de equipamento, as empresas brasileiras ainda não conseguiram desenvolver este mecanismo totalmente nacional. Este tipo de mecanismo tem grande aplicação na área industrial, móbile e aeronáutica. A importância do desenvolvimento deste trabalho justifica-se pela conquista de uma tecnologia dominada apenas por empresas estrangeiras, causando nas indústrias brasileiras que utilizam este mecanismo uma dependência tecnológica. Calcular e desenhar um determinado mecanismo não garante o seu perfeito funcionamento e também não assegura um sucesso sob o ponto de vista mercadológico. Portanto, foi realizado um estudo minucioso, além de uma discussão sobre o assunto com técnicos e engenheiros da industria sobre a melhor forma de usinagem e montagem. Esta etapa precisa ser considerada tão importante quanto necessária para o projetista. No desenvolvimento deste trabalho há uma apresentação sobre as bombas hidrostáticas disponíveis no mercado assim como tipos de servomecanismos aplicados em outros equipamentos, tais como, as direções hidráulicas. É apresentado detalhadamente cada um dos seus componentes em desenhos em 2D e 3D para explicar o funcionamento e a montagem / Designing of servomechanism devices are activities that few companies have developed around the world. A research in order to obtain information about the design of this kind of mechanism has revealed only a small amount of technical bulletins. Maybe because of the lacking of a specific literature about designing and how this kind of mechanism works, brazilian industries have not yet developed a true national design. This mechanism has many application in the industrial, mobile and aeronautical area. How important this work is can be justified by the conquering of this technology in a world where only foreign industries have it. Calculating and drawing are not sufficient steps to have a machine running and are not a guarantee of success in the market too. That is why a detailed study, besides a discussing with machine operators and industry engineers, was conducted in order to obtain better machining and assembling processes. This step must be considered as important as necessary. Therefore in developing this work, at first, the pumps available in the market are described and so are the servomechanisms applied to other machines, such as the power steering ones. The work itself presents every component of the servo in detailed 2D and 3D drawings in order to explain the ways of running and assembling
3

Modelagem de um servomecanismo para acionamento da placa swashplate de uma bomba de pistões axiais de vazão variável /

Bazarin, Felipe Yamane. January 2010 (has links)
Orientador: João Zangrandi Filho / Banca: Mauro Pedro Peres / Banca: Anselmo Monteiro Ilkiu / Resumo: O desenvolvimento do projeto e a manufatura de servocomandos hidráulicos é privilégio de poucas empresas no mundo. Uma pesquisa para obter informações sobre o projeto deste tipo de equipamento revelou pouquíssimas informações técnicas sobre este assunto. Talvez pela falta de uma literatura específica sobre o projeto deste tipo de equipamento, as empresas brasileiras ainda não conseguiram desenvolver este mecanismo totalmente nacional. Este tipo de mecanismo tem grande aplicação na área industrial, móbile e aeronáutica. A importância do desenvolvimento deste trabalho justifica-se pela conquista de uma tecnologia dominada apenas por empresas estrangeiras, causando nas indústrias brasileiras que utilizam este mecanismo uma dependência tecnológica. Calcular e desenhar um determinado mecanismo não garante o seu perfeito funcionamento e também não assegura um sucesso sob o ponto de vista mercadológico. Portanto, foi realizado um estudo minucioso, além de uma discussão sobre o assunto com técnicos e engenheiros da industria sobre a melhor forma de usinagem e montagem. Esta etapa precisa ser considerada tão importante quanto necessária para o projetista. No desenvolvimento deste trabalho há uma apresentação sobre as bombas hidrostáticas disponíveis no mercado assim como tipos de servomecanismos aplicados em outros equipamentos, tais como, as direções hidráulicas. É apresentado detalhadamente cada um dos seus componentes em desenhos em 2D e 3D para explicar o funcionamento e a montagem / Abstract: Designing of servomechanism devices are activities that few companies have developed around the world. A research in order to obtain information about the design of this kind of mechanism has revealed only a small amount of technical bulletins. Maybe because of the lacking of a specific literature about designing and how this kind of mechanism works, brazilian industries have not yet developed a true national design. This mechanism has many application in the industrial, mobile and aeronautical area. How important this work is can be justified by the conquering of this technology in a world where only foreign industries have it. Calculating and drawing are not sufficient steps to have a machine running and are not a guarantee of success in the market too. That is why a detailed study, besides a discussing with machine operators and industry engineers, was conducted in order to obtain better machining and assembling processes. This step must be considered as important as necessary. Therefore in developing this work, at first, the pumps available in the market are described and so are the servomechanisms applied to other machines, such as the power steering ones. The work itself presents every component of the servo in detailed 2D and 3D drawings in order to explain the ways of running and assembling / Mestre
4

Water-Bath Temperature Controller

Noble, D. F., Pearce, D. 01 May 1978 (has links)
No description available.
5

A NEW PIEZOELECTRIC MICROACTUATOR WITH TRANSVERSE AND LATERAL CONTROL OF HEAD POSITIONING SYSTEMS FOR HIGH DENSITY HARD DISK DRIVES

Han, Younghee 01 January 2005 (has links)
In high density magnetic hard disk drives, both fast track seeking and extremely accurate positioning of the read/write head are required. A new piezoelectric microactuator with transverse and lateral control of the head positioning system for high density hard disk drives is proposed. First, the structure of the new piezoelectric microactuator is illustrated. Design of the new microactuator is based on the axial deformation of piezoelectric elements for lateral motion and the bimorph actuation of piezoelectric elements for transverse motion. Next, a mathematical model of the microactuator system is defined. Static properties associated with the displacement of the system are evaluated and then dynamic system equations of the system are evaluated. Frequency response of the system is studied based on the dynamic system equations of the actuator system. Dynamic properties of the system with a variety of system parameters are evaluated. Finally, the controller design for the actuator is presented. Simulation results show that the new actuator achieves a maximum stroke of displacement of more than 0.2m with servo bandwidth of more than 5 kHz in the lateral direction and the flying height is decreased to less than 6 nm with resonance frequency of more than 100 kHz under the 0.5 % damping assumption. The new piezoelectric microactuator improves performance of high density hard disk drives by increasing servo bandwidth and decreasing flying height.
6

Linear-time invariant Positive Systems: Stabilization and the Servomechanism Problem

Roszak, Bartek 17 January 2012 (has links)
Positive systems, which carry the well known property of confining the state, output, and/or input variables to the nonnegative orphant, are of great practical importance, as the nonnegative property occurs quite frequently in numerous applications and in nature. These type of systems frequently occur in hydrology where they are used to model natural and artificial networks of reservoirs; in biology where they are used to describe the transportation, accumulation, and drainage processes of elements and compounds like hormones, glucose, insulin, and metals; and in stocking, industrial, and engineering systems where chemical reactions, heat exchanges, and distillation processes take place. The interest of this dissertation is in two key problems: positive stabilization and the positive servomechanism problem. In particular, this thesis outlines the necessary and sufficient conditions for the stabilization of positive linear time-invariant (LTI) systems using state feedback control, along with providing an algorithm for constructing such a stabilizing regulator. Moreover, the results on stabilization also encompass the two problems of the positive separation principle and stabilization via observer design. The second, and most emphasized, problem of this dissertation considers the positive servomechanism problem for both single-input single-output (SISO) and multi-input multi-output (MIMO) stable positive LTI systems. The study of the positive servomechanism problem focuses on the tracking problem of nonnegative constant reference signals for unknown/known stable SISO/MIMO positive LTI systems with nonnegative unmeasurable/measurable constant disturbances via switching tuning clamping regulators (TcR), linear quadratic clamping regulators (LTQcR), and ending with MPC control. Finally, all theoretical results on the positive servomechanism problem are justified via numerous experimental results on a waterworks system.
7

Linear-time invariant Positive Systems: Stabilization and the Servomechanism Problem

Roszak, Bartek 17 January 2012 (has links)
Positive systems, which carry the well known property of confining the state, output, and/or input variables to the nonnegative orphant, are of great practical importance, as the nonnegative property occurs quite frequently in numerous applications and in nature. These type of systems frequently occur in hydrology where they are used to model natural and artificial networks of reservoirs; in biology where they are used to describe the transportation, accumulation, and drainage processes of elements and compounds like hormones, glucose, insulin, and metals; and in stocking, industrial, and engineering systems where chemical reactions, heat exchanges, and distillation processes take place. The interest of this dissertation is in two key problems: positive stabilization and the positive servomechanism problem. In particular, this thesis outlines the necessary and sufficient conditions for the stabilization of positive linear time-invariant (LTI) systems using state feedback control, along with providing an algorithm for constructing such a stabilizing regulator. Moreover, the results on stabilization also encompass the two problems of the positive separation principle and stabilization via observer design. The second, and most emphasized, problem of this dissertation considers the positive servomechanism problem for both single-input single-output (SISO) and multi-input multi-output (MIMO) stable positive LTI systems. The study of the positive servomechanism problem focuses on the tracking problem of nonnegative constant reference signals for unknown/known stable SISO/MIMO positive LTI systems with nonnegative unmeasurable/measurable constant disturbances via switching tuning clamping regulators (TcR), linear quadratic clamping regulators (LTQcR), and ending with MPC control. Finally, all theoretical results on the positive servomechanism problem are justified via numerous experimental results on a waterworks system.
8

Projeto e desenvolvimento de um sistema inteligente para alinhamento de uma antena parabólica receptora

Marcos César Rafael 25 November 2011 (has links)
O objetivo deste trabalho é projetar e desenvolver um sistema automatizado inteligente para o alinhamento de uma antena receptora com refletor parabólico aplicado a comunicação via satélite. Com base em procedimentos empíricos para o alinhamento manual de uma antena parabólica, foi concebida e desenvolvida uma solução tecnológica empregando hardware e software. O sistema concebido utiliza um GPS, para prover a localização espacial instantânea da antena receptora e um receptor digital, que fornece a relação portadora / ruído de recepção. A principal contribuição deste trabalho foi o projeto e desenvolvimento de um sistema computacional inteligente, denominado Sistema Inteligente de Alinhamento de Satélite que visa a automatizar o alinhamento de antena receptora. Para um determinado satélite, o sistema utiliza a informação sobre a qualidade do sinal recebido para acionar um servomecanismo responsável pelo alinhamento da antena. Verificou-se que quando a antena estiver na posição desejada, a relação portadora ruído deverá estar acima de 8 dB para uma boa qualidade de recepção. Foi desenvolvido um projeto de um sistema inteligente para uma varredura em torno do valor de referência de posição da antena, o qual se denominou ajuste fino da posição da antena. Nossa inédita abordagem para o ajuste fino projetou-se um controlador fuzzy do tipo Mandani, cujas regras foram geradas de acordo com o processo de posicionamento manual da antena parabólica. Nossa solução permitiu melhorar a relação portadora / ruído de recepção. / The objective of this work is to design and develop an intelligent automated system for the alignment of a receiving antenna with parabolic reflector applied to satellite communication. Based on empirical procedures manual for the manual alignment of a parabolic antenna, we designed and developed a technological solution using hardware and software. The system uses a GPS to provide the initial spatial location of the receiving antenna and a digital receiver to provide the carrier-to-noise ratio. The main contribution of this work was the design and development of an intelligent computational system which aims at automating the receiving antenna alignment. For a given satellite, through the dynamic handling of relocate the receiving antenna, the system uses information about the quality of the received signal to drive the servo responsible for aligning the antenna. We found that, the antenna is in the desired position, the carrier-to-noise ratio should be above 8 dB for a good reception quality. We developed the project of an intelligent system to scan around the reference antenna position value, which was called the antenna position fine tuning. Our new approach consisted in a fuzzy controller type Mandani, generated according to the manual process of maneuvering the dish. Our solution has improved the carrier-to-noise ratio by repositioning the antenna in the desired position.
9

Optimalizace hydraulického systému a jeho prvků pro malá dopravní letadla / Optimization of Hydraulic System and its Components for Commuter Category Airplanes

Kameník, Luboš January 2012 (has links)
The dissertation thesis deals with optimization of the selected areas of the hydraulic system for small and medium transport aircrafts. Newly developed small aircraft EV-55 is a representative in the category of the small aircrafts . The selected areas of the hydraulic systems , important and useful for domestic producers of the hydraulic devices and whole hydraulic systems for the airplane EV-55 , are subjected to optimization efforts in the dissertation thesis. Design parameters of the hydraulic system (type of hydraulic source, level of pressure, weight of connecting tube), hydraulic devices ( tribology, machining process), simulation of the servomechanism and areas of diagnostic of technical status of the hydraulic system are optimized in the dissertation thesis.
10

Optimalizace hydraulického systému a jeho prvků pro malá dopravní letadla / Optimization of Hydraulic System and its Components for Commuter Category Airplanes

Kameník, Luboš January 2012 (has links)
The dissertation thesis deals with optimization of the selected areas of the hydraulic system for small and medium transport aircrafts. Newly developed small aircraft EV-55 is a representative in the category of the small aircrafts . The selected areas of the hydraulic systems , important and useful for domestic producers of the hydraulic devices and whole hydraulic systems for the airplane EV-55 , are subjected to optimization efforts in the dissertation thesis. Design parameters of the hydraulic system (type of hydraulic source, level of pressure, weight of connecting tube), hydraulic devices ( tribology, machining process), simulation of the servomechanism and areas of diagnostic of technical status of the hydraulic system are optimized in the dissertation thesis.

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