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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

Modular production systems : a motion control scheme for actuators

Rogers, Graham George January 1990 (has links)
No description available.
2

Servo Tracking with Parallel Trinocular Cameras

Jiang, Jian-hung 30 June 2005 (has links)
none
3

Improvement of Stamping Operations by using Servo Press and Servo Hydraulic Cushions - Case Studies

Mehta, Pratik Nitin 07 December 2017 (has links)
No description available.
4

Self-tuning digital controllers for servo systems

Al-Sadigi, G. M. January 1987 (has links)
No description available.
5

Optically-powered normally-closed fail-safe hydraulic valves

Jackson, Philip Richard January 1996 (has links)
No description available.
6

On-line self-optimisation of an electro-hydraulic servo control system

Lu, C. January 1988 (has links)
No description available.
7

Control of hybrid machines

Bradshaw, William Kenneth January 1997 (has links)
No description available.
8

Wireless control of wall switches : A module that controls your existing wall switch with an application / Trådlös styrning av väggströmbrytare

Örjegård, Johan January 2017 (has links)
In this project a home-automation-solution is developed that wirelessly can control an existing wall switch with an application from a smart device. The purpose of the project is to develop a new solution that doesn’t require any electrical knowledge to mount the solution. Exiting solutions for controlling a switch require a module that is connected in series with the switch. The project will develop a module that can be mounted next to the selected wall switches to control them without electrical connection to the AC-voltage of the switch. Instead there is a servo that physically press the switch that is controlled. The servo motor is controlled wirelessly via Bluetooth Low Energy using an Android application, thus, a force is applied to the switch to turn on or off. A rechargeable lithium battery of 3.7 volts powers the whole module. Therefore, a "power-board" was developed that step up the voltage to 5 V. There are also components on the board that manage battery charging via microUSB. The Android application communicates via a Bluetooth Low Energy module that is mounted on a CPU board and has been developed and specifically manufactured to fit into the project. Both the power-board and processor-board is developed from own drawings and PCB layouts, and made with a manual etching method. The chassis has also been designed and manufactured with a 3D printer. The chassis holds all circuit boards, battery and a mount for the servo. The result is a working prototype that can be mounted on a switch and then operate the switch within the range of BLE. The prototype has a run time of each charging cycle of about 60 days under conditions that it is operated, on average, three times per day. / I detta projekt utvecklas en hemautomationslösning som kan styra befintliga väggströmbrytare trådlöst via en applikation från en smart enhet. Syftet med projektet är att utveckla en ny lösning där det inte krävs någon elinstallationskunskap för att montera lösningen. Dagens lösningar för att trådlöst styra en strömbrytare kräver att en modul kopplas in i serie med strömbrytaren. I projektet utvecklas en modul som kan monteras bredvid utvalda strömbrytare för styrning av dem utan att behöva ansluta sig galvaniskt till brytarens starkström. I stället sitter en servomotor i modulen som fysiskt trycker på den strömbrytare som skall styras. Servomotorn kan styras trådlöst via Bluetooth Low Energy med hjälp av en androidapplikation, på så sätt appliceras en kraft på brytarvippan och slå på eller av den. Hela modulen är strömförsörjd av ett laddningsbart litiumbatteri på 3,7 volt. Därför har ett spänningskort utvecklats som växlar upp spänningen till 5 V. På spänningskortet finns även komponenter som hanterar laddning av batteriet via microUSB. Applikationen kommunicerar via en BLE-modul som i sin tur sitter monterad på ett processorkort som har utvecklats och tillverkas speciellt för att passa in i detta projekt. Både spänningskortet och processorkortet är utvecklade ifrån egna ritningar och PCB-layouter samt tillverkade med en manuell etsningsmetod. Ett chassi har också konstruerats och tillverkats med en 3D-skrivare. Chassit rymmer alla kretskorten, batteriet och har ett motorfäste för montering av servomotorn. Resultat har blivit en fungerande prototyp som kan monteras på en strömbrytare och därefter manövrera brytaren inom den räckvidd som BLE klarar av. Prototypen har en drifttid på cirka 60 dagar under förutsättningar att den manövreras i genomsnitt vid tre tillfällen per dygn.
9

[en] LEARNING CONTROL OF HIGH FREQUENCY SERVO: HYDRAULIC SYSTEMS / [pt] CONTROLE POR APRENDIZADO DE SISTEMAS SERVO: HIDRÁULICOS DE ALTA FREQÜÊNCIA

JUAN GERARDO CASTILLO ALVA 28 October 2008 (has links)
[pt] Sistemas hidráulicos são usados onde se requerem forças e torques relativamente altos, alta velocidade de resposta para o início, parada e reversão da velocidade. Eles são usados em sistemas industriais, em robótica, simuladores de movimento, plantas automatizadas, exploração de minérios, prensas, e especialmente em sistemas de testes de fadiga de materiais. As máquinas de testes de fadiga baseadas em sistemas servo-hidráulicos têm como propósito fazer ensaios nos materiais para prever a vida útil em serviço. Os ensaios de fadiga são quase sempre independentes da freqüência de trabalho. Para uma dada resistência do material e magnitudes das tensões alternadas e médias aplicadas, a vida à fadiga depende essencialmente do número de ciclos de carga aplicados ao material testado. Por esse motivo, trabalhar com a máquina de ensaios de materiais a uma freqüência elevada traz vantagens de redução de tempo e custo dos ensaios, sem interferir nos resultados. A aplicação da carga pode ser repetida milhões de vezes, em freqüências típicas de até cem vezes por segundo para metais. Para se atingirem estas freqüências, relativamente altas para um teste de fadiga, é necessário um sistema de controle eficiente. Nesta dissertação, técnicas de controle por aprendizado são desenvolvidas e aplicadas a uma máquina de ensaios de materiais, permitindo a aplicação de carregamentos de amplitude variável em alta freqüência. A metodologia proposta consiste em fazer um controle do tipo bang-bang, restringindo à servo-válvula do sistema a trabalhar sempre nos seus limites extremos de operação, i.e., procurando mantê-la sempre completamente aberta em uma ou outra direção. Devido à dinâmica do sistema, os pontos de reversão devem ficar antes dos picos e vales de força ou tensão desejada. O instante de reversão é um parâmetro que depende de diversos fatores, como a amplitude e carga média da solicitação, e também é influenciado por zonas mortas causadas, e.g., por folgas na fixação dos corpos de prova. Para que a servo-válvula trabalhe no limite de seu funcionamento, o algoritmo de aprendizado obtém os instantes ótimos para as reversões, associados a variáveis adimensionais com valores entre 0 e 1, armazenados em tabelas específicas para cada tipo de carregamento. A lei de aprendizado preenche e atualiza constantemente os valores das tabelas durante a execução dos testes, melhorando a resposta do sistema a cada evento. Apresentam-se a modelagem dinâmica de uma máquina servohidráulica e de sua malha de controle, e simulações comparando o controle PID com o controle por aprendizado proposto. A validação experimental é feita em uma máquina servo-hidráulica de ensaios de fadiga. Para este fim, um software de controle em tempo real foi especialmente desenvolvido e implementado em um sistema computacional CompactRIO. Os resultados demonstram a eficiência da metodologia proposta. / [en] Hydraulic systems are used where relatively high forces and torques are required, or when high response speeds are necessary. They are used in industrial systems, robotics, movement simulators, automated plants, ore exploration, presses, and especially in fatigue testing systems. Fatigue tests are usually performed on servo-hydraulic systems, in order to predict the behavior of materials and their life in service. Fatigue tests are almost always independent of the loading frequency. For a given material and magnitudes of alternate and mean stresses, the fatigue life depends essentially on the number of applied load cycles on the tested material. For this reason, working with the material testing machine at high frequencies brings the advantages of reduction in time and cost, without altering the results. The application of the load can be repeated millions of times, in frequencies of up to one hundred times per second for metals, or even more. To achieve such frequencies, relatively high for a fatigue test, it is necessary to use an efficient control system. In this thesis, learning control techniques are developed and applied to a materials testing machine, allowing the application of constant or variable amplitude loads in high frequency. The proposed methodology consists of implementing a bang-bang type control, restricting the system servo-valve to always work at its extreme limits of operation, i.e., always keeping it completely open in one or the other direction. Due to the system dynamics, the reversion instant must happen before achieving the peaks and valleys of desired force (or stress, strain, etc.). The reversion instant is a parameter that depends on several factors, such as the alternate and mean loading components. It is also influenced by dead zones caused, e.g., by the slack in the mounting between a CTS specimen and the machine pins. As the servo-valve works in its limits of operation, the learning algorithm tries to obtain the optimal instants for the reversions, associating them to a non dimensional variable with values between 0 and 1, stored in specific tables. The learning law constantly updates the values of the table during the execution of the tests, improving the system response. In this work, the dynamic modeling of a servo-hydraulic machine is presented, together with its control scheme. Simulations are performed to compare results from PID and learning controls. The experimental validation is made using a servohydraulic testing machine. For this purpose, real time control software is developed and implemented in a CompactRIO computational system. The results demonstrate the efficiency of the proposed methodology.
10

Visual Servo of Underwater Pipeline Following

Jiang, Bor-tung 14 July 2008 (has links)
This thesis describes a vision-based method for ROV¡¦s underwater pipeline recognition task. In this research, we tried to overcome the poor image quality of the underwater circumstance and the condition when seaweed is in the scene. Edge information and line feature of the pipeline are used in this method. Edge image is obtained after preprocessing to extract line feature. In this thesis we focused on the recognition of pipeline, trying to provide useful navigation information for further development of the ROV¡¦s control system.

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