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Dissertations / Theses on the topic 'Displacement controlled'
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Lux, Jan, and Hubertus Murrenhoff. "Experimental loss analysis of displacement controlled pumps." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199825.
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Current efficiency measurements of variable hydraulic axial piston pumps are performed with the displacement system locked at maximum volume, thus without the controller. Therefore, the controller’s effect on the efficiency is not quantified at state of the art measurements. Former research on control systems mainly focused on the dynamic behaviour. This paper aims to quantify the losses in the displacement and control system and to research the dependencies of those. Therefore, a test rig is built up at IFAS to measure the control power of displacement controlled pumps. Furthermore, a simulation tool is developed to increase the understanding of the loss mechanisms of the investigated control systems. In conclusion, the paper shows the potential of efficiency improvements for displacement controlled pumps.
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Elton, Mark David. "An efficient haptic interface for a variable displacement pump controlled excavator." Thesis, Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/34653.
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Human-machine interfaces influence both operator effectiveness and machine efficiency. Further immersion of the operator into the machine’s working environment gives the operator a better feel for the status of the machine and its working conditions. With this knowledge, operators can more efficiently control machines. The use of multi-modal HMIs involving haptics, sound, and visual feedback can immerse the operator into the machine’s environment and provide assistive clues about the state of the machine. This thesis develops a realistic excavator model that mimics a mini-excavator’s dynamics and soil interaction during digging tasks. A realistic graphical interface is written that exceeds the quality of current academic simulators. The graphical interface and new HMI are placed together with a model of the excavator’s mechanical and hydraulic dynamics into an operator workstation. Two coordinated control schemes are developed on an haptic display for a mini-excavator and preliminary tests are run to measure increases in operator effectiveness and machine efficiency.
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Cierocka, Joanna, and Jiayue Tang. "Vibrational tests of preloaded rubber vibration isolators : A cam controlled displacement excitation." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-53703.
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Vibrations are very common phenomenon. It influences structures and generates acoustic noise which might be harmful to human beings. The vibration isolator was invented to reduce the effect from vibrations. However, the behavior of rubber material, which many vibration isolators are made of, is hard to predict. Consequently, vibration tests are needed to obtain the dynamic properties of rubber isolator.In this case, a six-year old LORD 2204-5 rubber isolator provided by Atlas Copco was tested. The aim of this paper is to obtain the FRF (Frequency Response Function) diagram which can describe the property of the rubber material. Moreover, the influence of aging of rubber material on the dynamic properties was studied.As the vibration test should simulate the working environment of the isolators that are both a static load from the structure and a dynamic force from the engine, a new excitation method was designed. The camshaft with the shape of an epitrochoid induced the sinusoidal signal of the isolator and the frame transferred the static load from the hydraulic machine. The artificial aging was performed in a hot air oven in 90°C for 42 hours, which according to Arrhenius equation should be equivalent to six years of natural aging. The vibration isolator was tested again after being aged.The obtained data showed that the aging process decreased the stiffness of the material. The results were corresponding with other studies regarding aging of rubber.
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Busquets, Enrique, and Monika Ivantysynova. "Toward Supervisory-Level Control for the Energy Consumption and Performance Optimization of Displacement-Controlled Hydraulic Hybrid Machines." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200450.
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Environmental awareness, production costs and operating expenses have provided a large incentive for the investigation of novel and more efficient fluid power technologies for decades. In the earth-moving sector, hydraulic hybrids have emerged as a highly efficient and affordable choice for the next generation hydraulic systems. Displacementcontrolled (DC) actuation has demonstrated that, when coupled with hydraulic hybrids, the engine power can be downsized by up to 50% leading to substantial savings. This concept has been realized by the authors‘ group on an excavator prototype where a secondary-controlled hydraulic hybrid drive was implemented on the swing. Actuatorlevel controls have been formulated by the authors‘ group but the challenge remains to effectively manage the system on the supervisory-level. In this paper, a power management controller is proposed to minimize fuel consumption while taking into account performance. The algorithm, a feedforward and cost-function combination considers operator commands, the DC actuators‘ power consumption and the power available from the engine and hydraulic hybrid as metrics. The developed strategy brings the technology closer to the predicted savings while achieving superior operability.
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Quick, Mark Eric. "A biomechanical analysis of growing rods used in the management of early onset scoliosis (EOS)." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/70333/1/Mark_Quick_Thesis.pdf.
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The use of dual growing rods is a fusionless surgical approach to the treatment of early onset scoliosis (EOS) which aims to harness potential growth in order to correct spinal deformity. This study compared through in-vitro experiments the biomechanical response of two different rod designs under axial rotation loading. The study showed that a new design of telescoping growing rod preserved the rotational flexibility of the spine in comparison with rigid rods indicating them to be a more physiological way to improve the spinal deformity.
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Gojuri, Arun. "Stability of End Notched Flexure Specimen." Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-4487.
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This paper deals with two-dimensional Finite Element Analysis of the End Notched Flexure (ENF) specimen. The specimen is known to be unstable if the crack length is shorter than some critical crack length acr. A geometric linear two-dimensional Finite Element (FE) analysis of the ENF specimen is performed to evaluate acr for isotropic and orthotropic elastic materials, respectively. Moreover, the Mode II Energy Release Rate (ERR) JII and the compliance of the specimen are calculated. The influence of anisotropy is studied. Comparisons are made with the results from beam theory. This work is an extension of previous work.
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Tufarelli, T. "Qubit-controlled displacements in Markovian environments." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1344094/.
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Dean, Patrick T. "Modern control design for a variable displacement hydraulic pump." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4647.
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Thesis (M.S.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 21, 2009) Includes bibliographical references.
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Schoemacker, Florian, Felix Fischer, and Katharina Schmitz. "Damping strategies for energy efficient pressure controllers of variable displacement pumps." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71108.
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In hydraulic-mechanically controlled variable displacement pumps, the actual pump controller produces additional power losses. Due to the low damping coefficients of all pump controller’s components, hydraulic-mechanically pressure controlled pumps use to oscillate while adjusting the pressure level in the hydraulic system. In several state-of-the-art variable pump controllers, a damping orifice connects the control actuator’s displacement chamber with the reservoir. This bypass dampens the movement of the control actuator but also leads to bypass losses during steady-state operation of the pump. A new concept for damping via feedback loops avoiding bypass losses is presented in t his paper.
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Alshammari, Awadh Tulaiahan. "An investigation into different types of controllers of variable displacement axial-piston pumps." Thesis, University of the West of England, Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415881.
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Foo, Jong Teck. "Selection of controller gains for an electromagnetic suspension system." Ohio : Ohio University, 1993. http://www.ohiolink.edu/etd/view.cgi?ohiou1175287253.
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Moreira, Attus Pereira. "Métodos de cálculo de coordenadas tridimensionais para o controle de obras de engenharia." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-01022018-153528/.
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O presente trabalho propõe duas novas metodologias para a determinação de coordenadas tridimensionais visando o emprego no controle de obras de engenharia. Os dois métodos propostos fundamentam-se na concepção de um ponto fixo, visível simultaneamente por todos os aparelhos envolvidos no processo e em uma direção de orientação. O primeiro método tem como princípio básico a minimização de uma função matemática, definida pelo somatório das distâncias entre as linhas de visadas dos aparelhos e o alvo. O segundo fundamenta-se no ajustamento pelo Método dos Mínimos Quadrados, aplicado às equações de erros, que são determinadas em função das coordenadas do centro ótico de cada aparelho e dos ângulos zenitais e azimutais medidos. Esse segundo método proporciona, ao mesmo tempo, que sejam estimadas as precisões dos elementos envolvidos no cálculo das coordenadas do alvo e, ainda, ajusta os valores iniciais das coordenadas do centro ótico dos aparelhos. Ambos os métodos podem ser empregados para a verificação de recalques ou deslocamentos estruturais nas provas de carga em obras de engenharia. Os resultados obtidos comprovam que os métodos propostos determinam coordenadas tridimensionais com maior precisão que os principais métodos apresentados na revisão da literatura e podem ser empregados no controle de obras de engenharia.The purpose of this work is to present new methodologies to determine 3-D coordinates to check engineer works. The two proposed methods are well-founded on a conception of a fixed point and a direction that are proposed. This fixed point must be visible by all surveying equipments envolved in the process to determine 3-D coordinates. The first method presented in this work is based on a mathematic function that must be minimized and this function is defined by the sum of the distances of the target and the sightlines from the surveying equipments directed to the target. The second method presented is based on the L.S.M. adjustment process. This method uses the errors equations that are functions of the 3-D coordinates of the optic center of the surveying equipments envolved in this process. It also uses the azimuth and zenith angles related to the target measured. This method provides at the same time, a way to estimate the precisions of ali elements envolved in 3-D coordinates determination calculus of the target and it also provides the adjustment of the 3-D coordinates of the optic centers of the surveying equipments used to measure the angles. The conception of the orientation point provides more flexibility in a performance of these two methods. The two methods can be employed to check structural displacements and pressing down in charge experiments in engineer works. The results presented in this work validate that these two proposed methods determine 3-D coordinates with more precision and accuracy than the main methods presented in literature revision and may be able to check engineer works.
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McBrayer, William Daniel. "Let There Be War: Competing Narratives and the Perpetuation of Violence in Georgia." Ohio : Ohio University, 2009. http://www.ohiolink.edu/etd/view.cgi?ohiou1230892552.
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Larocca, Ana Paula Camargo. "O uso do GPS como instrumento de controle de deslocamentos dinâmicos de obras civis - aplicação na área de transportes." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/18/18137/tde-29052006-170441/.
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Este trabalho apresenta o desenvolvimento de metodologia para avaliar a utilização do Sistema de Posicionamento Global (GPS) como ferramenta de pesquisa no estudo do comportamento dinâmico de obras viárias. Para ser caracterizado como um instrumento de medição, foi estudada a potencialidade de um método, que se fundamenta numa forma específica de coleta e processamento de dados GPS; análise dos resíduos resultantes do processamento da dupla diferença de fase e aplicação de análise espectral para filtragem de informações indesejáveis (multicaminhamento dos sinais GPS). A coleta envolve um oscilador eletro-mecânico, especialmente projetado, que permite calibrar as medidas de amplitude e freqüência das oscilações mensuráveis pela obra sob teste. Inúmeros experimentos foram realizados em ambientes de reflexões e difrações variáveis e com diversos tipos de receptores e antenas GPS. Alguns ensaios foram realizados utilizando, simultaneamente, equipamentos como transdutores de deslocamento, acelerômetros e estações totais. Comparando os resultados obtidos, mesmo com valores prescritos em normas e códigos, afirma-se que o GPS, sob o método de coleta de dados testado, é um instrumento confiável para detecção e caracterização do comportamento dinâmico de estruturas, apresentado confiabilidade para as medições realizadas, da ordem de décimos de milímetro. Quanto à detecção das freqüências, as mais baixas ficam comprometidas pela presença do multicaminhamento e as mais elevadas têm a detecção limitada pela máxima taxa de coleta dos receptores (Lei de Nyquist)This work presents the development of a methodology to appraise the use of Global Positioning System (GPS) as a tool for researching of dynamic behavior of road transport structures. To be characterized as an instrument for measuring it was studied the potentiality of one method which includes a specific mode of GPS data collection; analyses of double difference phase residuals and application of spectral analyses and filtering for excluding undesirable information (multipath). The GPS data collected applies an electro-mechanical oscillator, specially built for that, which permits to calibrate the measures of frequency and amplitude of structures oscillations under dynamic load test. Several field tests were carried out in vicinities with high and low capacity of causing signal reflections and diffractions and with different types of GPS receivers and GPS antennas. A couple of fields were carried out using, at the same time, transducers of displacement, accelerometers and total stations. Comparing these results obtained even with values of codes, it is affirmed that GPS, under the data collection method tested, it is a trustworthy instrument for detection and characterization of dynamic behavior of structures, presenting reliability of measures ranging around tenths of millimeters. The very low frequencies are highly degraded by multipath and very high frequencies have its detection limited by the receiver data rate (Theorems Nyquist)
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Nicolau, Francisca Edcarla de Araujo. "Raios de curvatura, larguras de bitola e comprimentos do cabeçalho influenciam na qualidade do paralelismo? /." Jaboticabal, 2020. http://hdl.handle.net/11449/192275.
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Orientador: Carlos Eduardo Angeli FurlaniResumo: As propriedades que atuam no deslizamento lateral de um equipamento de arrasto em áreas agrícolas, variam amplamente, indo desde as relacionadas ao solo até aos parâmetros envolvidos no sistema trator-equipamento que podem afetar o deslocamento lateral. O objetivo com o estudo foi mensurar o erro de paralelismo do conjunto trator-protótipo em função de diferentes raios de curvatura, larguras de bitola e comprimentos do cabeçalho de um protótipo de arrasto, além de avaliar a variabilidade do processo por meio do Controle Estatístico do Processo. Os testes foram realizados em área experimental da Universidade Estadual Paulista (Unesp), Faculdade de Ciências Agrárias e Veterinárias, Câmpus de Jaboticabal. Foi adaptado o chassi de uma semeadora-adubadora, que possibilitasse mudança no comprimento do cabeçalho e variação na largura da bitola do equipamento, o qual denominamos protótipo de arrasto. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 5x4x15, com cinco comprimentos do cabeçalho e quatro larguras de bitola do protótipo em quinze raios de curvatura médio. A medição do paralelismo entre as passadas do conjunto trator-protótipo foi obtida por meio de um instrumento desenvolvido que denominamos “pirulito” e com o auxílio de uma trena. Nos raios de 16,4 m e de 20 m os erros de paralelismo são maiores, em todas as bitolas e vão diminuindo à medida que se aumenta a circunferência do raio. O comprimento do cabeçalho de 2,40 m, quando comparado com ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The properties that act on the lateral sliding of a trailed equipment in agricultural areas, change widely, ranging from those related to the soil to the parameters involved in the tractor-equipment system that can affect lateral displacement. The objective of the study was to measure the parallelism error of the tractor-prototype set as a function of different curvature radius, the widths of the gauge and the lengths of the header of a drag prototype, in addition, the evaluating process of the variability through the Statistical Process Control. The tests were carried out in an experimental area at the São Paulo State University (Unesp), School of Agricultural and Veterinary Sciences, Campus of Jaboticabal. The chassis of a seeder-fertilizer was adopted, so that it would allow a change in the length of the header and a variation in the width of the gauge of the equipment, which we call the trailed prototype. The experimental design was entirely randomized, in a 5x4x15 factorial scheme, with five header lengths and four widths of gauge of the prototype in fifteen average curvature radius. The measurement of the parallelism between the steps of the tractor-prototype set was obtained by using an instrument that we call “lollipop” and with the help of a measuring tape. In the 16.4 m and 20 m radius the parallelism errors were greater than the other gauges, and it decreased as the radius circumference increased. The header length of 2.40 m, when compared to the others, obtained t... (Complete abstract click electronic access below)
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Gálvez, Límaco Ángel Manuel. "Demodulação digital usando sinais em quadratura e controle de fase óptica aplicada a um vibrômetro baseado em um interferômetro de Michelson modificado /." Ilha Solteira, 2020. http://hdl.handle.net/11449/192101.
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Orientador: Cláudio KitanoResumo: Nesta dissertação de mestrado é apresentado um vibrômetro para a medição de deslocamentos nanométricos. O vibrômetro proposto está baseado em um interferômetro de Michelson modificado, homódino e em malha fechada. A demodulação em tempo real é executada inteiramente em modo digital, utilizando uma plataforma embarcada que realiza a aquisição de dados, processamento dos sinais, controle PI (proporcional-integral) e a geração dos sinais que acionam o modulador de fase óptica (baseado em uma célula Pockels) e o atuador piezoelétrico sob estudo. Dois sinais em quadratura de fase são obtidos a partir de um único sinal interferométrico utilizando uma tensão de modulação principal e, em seguida, a conhecida técnica de multiplicação cruzada é aplicada para calcular a variação da fase óptica de interesse. A condição de quadratura é atingida pelo próprio controlador PI por meio da análise da figura de Lissajous dos sinais fora de fase. O novo vibrômetro óptico é capaz de medir deslocamentos nanométricos, e é simples, barato, exato, imune ao desvanecimento e auto-consistente. O controlador PI é robusto, uma vez que o método de demodulação é capaz de trabalhar com elevado ruído eletrônico, variações indesejáveis no ganho do amplificador e na tensão de meia-onda da célula Pockels com a temperatura e outras perturbações externas. O novo sistema foi utilizado para determinar a magnitude da resposta em frequência de dois protótipos de atuadores piezoelétricos flextensionais multiatuados. As ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: A vibrometer to measure nanometric displacements is presented in this work. The proposed vibrometer is based on a modified closed loop homodyne Michelson interferometer. Real-time phase demodulation is carried out entirely in a digital mode, using an embedded platform that performs data acquisition, signal processing, PI (proportional-integral) control and the generation of signals that drive the electrooptic Pockels cell phase shifter and the piezoelectric actuator under test. Two phase quadrature signals are generated from a single interferometric output, using the interleaving action, in alternation, of a digitally generated principal modulating signal, and then the well-known cross-multiplication technique is applied to perform the computation of the phase shift of interest. The quadrature condition is reached by the PI control itself, using the length difference between the major axis and the minor axis of the ellipse formed by the Lissajous figure associated with the out of phase signals as the controller error signal. The new optical vibrometer is capable of measuring nanometric displacements, and is simple, inexpensive, accurate, immune to fading and self-consistent. The PI controller is robust, since the demodulation method is able to work under high electronic noise, undesirable variations in Pockels cell half-wave voltage with temperature, amplifier gain and other external entrances. The new method was used to determine the displacement frequency response curves of... (Complete abstract click electronic access below)
Mestre
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Salvador, Renan Pícolo. "Análise comparativa de métodos de ensaio para caracterização do comportamento mecânico de concreto reforçado com fibras." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3146/tde-29072013-115851/.
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O emprego de fibras para reforço de concreto é uma técnica bastante conhecida e estudada mundialmente. As mais conhecidas e estudadas são as fibras de aço, embora utilização das macrofibras poliméricas esteja amplamente difundida no mercado brasileiro. Entretanto, a caracterização do comportamento mecânico de concretos reforçados com essas macrofibras ainda deve ser mais bem avaliada. Dentre os diversos métodos utilizados para essa finalidade, os ensaios realizados com sistema fechado de controle de velocidade de deslocamento fornecem resultados mais confiáveis. A principal vantagem conferida por esse sistema está na avaliação desses compósitos em baixo nível de fissuração com maior acurácia. O desempenho desses compósitos foi estudado segundo as normas ASTM C1609 (2010), ASTM C1399 (2010) e EN 14651 (2007) e o método JSE-SF4 (1984). Os quatro procedimentos prescrevem ensaios de flexão de corpos-de-prova prismáticos para determinação da resistência residual pós-fissuração e da tenacidade. Os procedimentos americanos e o método japonês prescrevem configuração de aplicação de carga por dois cutelos superiores, posicionados sobre o terço médio do corpo-de-prova. Já a configuração do método europeu é de aplicação de carga por apenas um cutelo superior, centralizado em relação ao vão de ensaio, com corpos-de-prova com entalhe na face inferior. Foram estudadas uma macrofibra de polipropileno, nas dosagens de 0,22, 0,33, 0,50, 0,66, 0,82 e 1,0% em volume em três matrizes de concreto, com resistências médias à compressão de 30, 35 e 40MPa, e uma fibra de aço, nas dosagens de 0,19, 0,32 e 0,45% em volume em uma matriz de resistência média à compressão de 35MPa. Foi observado que a utilização da velocidade de deslocamento do corpo-de-prova como parâmetro de controle do ensaio forneceu boas condições de avaliação do compósito, devido à redução da instabilidade pós-pico. Com isso, a determinação da resistência residual do compósito nos níveis iniciais de deslocamento e fissuração da matriz foi mais bem caracterizada. Pela análise e comparação dos resultados, foram formuladas equações para estabelecer correlações entre os diferentes métodos de ensaio. Com o modelo de regressão utilizado na análise estatística foi possível verificar que a resistência à compressão da matriz, o tipo e o teor de fibra são as variáveis independentes que mais influenciam os resultados de resistência residual. Foi necessário estabelecer correlações para cada tipo de fibra separadamente, pois o comportamento de slip-softening ou de slip-hardening influencia as funções obtidas.The use of fibers for concrete reinforcing is a very common practice, used all over the world. Steel fibers are the most common and studied, although synthetic macrofibers are in very common use in the Brazilian market. However, the evaluation of the mechanical behavior of concrete reinforced with this type of fiber must be evaluated. A broad range of tests is available for this purpose. Tests performed under closed-loop displacement control provide more reliable results. The main advantage of that system is in the evaluation of the composite at low levels of crack opening with higher accuracy. In this study, the performance of these composites was examined according to the standard test methods ASTM C1609 (2010), ASTM C1399 (2010), EN 14651 (2007) and JSCE-SF4 (1984). These four methods prescribe flexural tests in prismatic specimens for the determination of post-crack residual strength and toughness. The American and the Japanese test methods prescribe four-point bending tests, while the European test method prescribes three-point bending tests and specimens with a notch in the bottom face. Two fibers were analyzed: a polypropylene macrofiber, used in the dosages of 0.22, 0.33, 0.50, 0.66, 0.82 and 1.0 in volume percentage, in three concrete matrices with average compressive strengths of 30, 35 and 40MPa, and a steel fiber, in the dosages of 0.19, 0.32 and 0.45 in volume percentage, in one concrete matrix of average compressive strength of 35MPa. It was observed that the use of the net displacement of the specimen as the parameter to control the load application provided good conditions for the evaluation of the mechanical behavior of the composite, due to the reduction of post-peak instability. Therefore, the determination of the residual strength of the composite in the initial levels of displacement and cracking of the matrix was better achieved. From the comparative analysis of the results, equations were developed to establish a correlation among the test methods. Based on the model used in the statistical analysis, the main independent variables that influence the results of residual strength are the compressive strength of the concrete matrix, the type and the content of the fiber. The equations were obtained separately according to the fiber type, because the behavior of slip-hardening or slip-softening influence the correlations.
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Martins, Diego de Oliveira. "Determinação de coordenadas espaciais a partir do método das distâncias mínimas." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18143/tde-19022014-101241/.
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O monitoramento de grandes estruturas está diretamente ligado à segurança das mesmas, pois sendo elas naturais ou artificiais, estão sempre sujeitas a variações em suas dimensões e posições, no espaço e no tempo, o que pode representar riscos sociais, ambientais e econômicos. Dessa maneira, a presente pesquisa apresenta um estudo sobre métodos de determinação de coordenadas espaciais, disponíveis na literatura e empregados atualmente nos trabalhos práticos de engenharia, quanto aos aspectos de monitoração estrutural, tendo por finalidade simular e determinar deslocamentos controlados de alvos. A dissertação tem como principal objetivo testar as vantagens dos procedimentos automáticos realizados por meio de estações totais robóticas a partir do uso de métodos de medição em estudo no Laboratório de Mensuração do Departamento de Transportes da Escola de Engenharia de São Carlos (STT/EESC/USP), em comparação com o método polar, convencionalmente utilizado na maioria dos projetos de monitoração estrutural. O principal método aplicado nesta dissertação é denominado Método das Distâncias Mínimas, o qual se fundamenta no princípio da minimização de funções matemáticas definidas pelo somatório das distâncias entre os pontos de medição e os alvos definidos para o monitoramento. As distâncias, neste caso, são determinadas a partir das medições de ângulos zenitais e azimutais medidos com estações totais robóticas e automáticas. Com isso, pretende-se mostrar que o uso de equipamentos topográficos modernos com capacidade para desenvolver rotinas de automação de busca e medição de alvos permite realizar medidas com alto nível de automação, controle e qualidade. Mostra-se nesta dissertação que a tecnologia de busca automática de prismas permite automatizar os procedimentos de mensuração aplicados ao monitoramento de estruturas, possibilitando auscultar estruturas de maneira contínua sem a interferência do operador, o que aumenta sensivelmente a qualidade dos resultados.The monitoring of large structures is directly linked to their safety, because they are always subject to variations in their dimensions and positions in space and time, which can pose social, environmental and economic risks, being the structures natural or artificial. Thus, the following research presents a study about the methods to determine spatial coordinates, available in the literature and currently employed in practical engineering, and also includes the structural issues of monitoring, aiming to simulate and determine controlled displacements of targets. This paper has as main objective to test the advantages of automatic procedures performed using robotic total stations using measurement methods in a study at the Measurement Transport Department Laboratory of the São Carlos School of Engineering (STT/EESC/USP), in comparison to the polar method, conventionally used in most structural monitoring projects. The main method applied in this thesis is called Minimum Distances Method, which is based on the principle of mathematical functions minimization defined by the sum of the distances between the measurement points and the targets set for the monitoring. The distances, in this case, are determined from the measurements of azimuth and zenithal angles measured with automatic and total robotic stations. The main purpose is to show that the use of modern surveying equipment with capacity to develop automation routines of search and targets measurement allows performing measurements with high level of automation, control and quality. It is shown in this paper that the technology of prisms automatic search permit to automate the measurement procedures applied to the monitoring of structures, enabling to continuously auscultate the structures without the operator interference, which significantly improves the quality of results.
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Dainez, Paulo Sérgio. "Contribuições para o acionamento do compressor linear ressonante sem sensor de posição." Universidade do Estado de Santa Catarina, 2010. http://tede.udesc.br/handle/handle/1903.
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Previous issue date: 2010-06-25Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In the resonant linear compressor the piston is drive by a linear actuator and a resonant mechanical spring directly in the reciprocating motion, this is a mass spring resonant system, eliminating bearing and crank of the conventional reciprocating compressors, and the friction loss has a significant reduction. The maximum displacement of the piston is regulating by the equilibration between the power supply by the actuator and the power transfer to the gas compression process. This type of the compressor is design to work at the resonant frequency of the mass spring system, in this condition the efficiency is maximum. Then the control must drive the linear actuator in the maximum displacement of the piston and adjust the drive frequency at the system resonant frequency. For enable of this process is necessary that piston position is known with precision, however the installation of a sensor have same difficulty, since the refrigeration compressor is hermetic system, and it have high pressure and temperature, with wide range of variation. This work develop the implementation of a full order linear observer to estimate the displacement and the velocity of the piston of the resonant linear compressor, and a control system able to drive the compressor in the maximum piston displacement and in the resonant frequency, and only measured a current of the linear actuator, without sensor inside de compressor. For this a nonlinear model of the compressor and a linear model with variable coefficients for the observer are develop, also a simulator of the system is develop, where the compressor model is controlled by the displacement and the velocity signals calculate by observer, demonstrated the feasibility of the proposed technique in the present work.
Nos compressores lineares ressonantes o pistão é acionado por um atuador linear e molas diretamente no sentido do seu movimento alternativo, formando um sistema massa-mola ressonante, eliminando assim os mancais mecânicos e o sistema biela e manivela dos compressores convencionais, reduzindo de forma significativa as perdas por atrito. A amplitude do deslocamento do pistão é regulada pelo equilíbrio da potência fornecida pelo atuador e a potência transferida para o processo de compressão do gás. Estes compressores são projetados para funcionar na frequência de ressonância do sistema massa-mola, nesta condição a eficiência do sistema é máxima. Assim, o controle deve acionar o atuador linear na máxima amplitude de deslocamento do pistão e ajustar a frequência de acionamento na frequência de ressonância do sistema. Para viabilizar este processo é necessário que o curso do pistão seja conhecido com precisão, porém a instalação de um sensor apresenta dificuldades, pois os compressores de refrigeração são herméticos e estão sujeitos a pressões e temperaturas elevadas e com grande faixa de variação. Este trabalho propõe a implementação de um observador de estados de ordem plena, para estimar o deslocamento e a velocidade do pistão do compressor linear ressonante, e um sistema de controle capaz de acionar o compressor no deslocamento máximo e na frequência de ressonância, medindo somente a corrente no atuador linear, sem a necessidade de sensores instalados dentro do compressor. Para isto desenvolve-se um modelo não linear do compressor e um modelo linear equivalente de coeficientes variáveis para o projeto do observador, também é desenvolvido um simulador do sistema, onde o modelo do compressor é controlado pelos sinais de deslocamento e velocidade calculados pelo observador, demonstrando a viabilidade da técnica proposta no presente trabalho.
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Bhamare, Rupali S. "Displacement controlled behaviour of strength degraded structures." 2010. http://repository.unimelb.edu.au/10187/7396.
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This research study represents an important contribution towards fulfilling the long-term objective of the research program in terms of assessing and controlling seismic risks of building structures in low and moderate seismic regions such as Australia. The research outcome enables the existing building stock to be assessed in an inexpensive way. Post-disaster agencies and insurance agencies could then better assess risk exposure. The displacement controlled phenomenon associated with conditions in low and moderate seismic regions has become the basis of a new performance assessment methodology for strength degraded structures.In low and moderate seismic regions the kinetic energy demand generated by a small or medium magnitude earthquake (M<7) (at an epicentral distance consistence with Peak Ground Velocity (PGV) of up to 80 mm/s on rock) will generally subside when the structure has been displaced to the maximum limit. Current design guidelines in seismic design and assessment of structures has been based on trading-off strength with ductility demand to accommodate large displacement without significant strength degradation to ensure that structures have sufficient energy dissipation capacity. The drift capacity recommended for strength degraded structures is quite low as per the current guidelines which are developed for high seismic regions and it is considered that a structure is deemed unsafe when the lateral strength has degraded by more than 20%. An important investigation has been undertaken to determine if such structures are actually unsafe, should the displacement controlled phenomenon be taken into account.
Therefore, the research described in this thesis is aimed at capitalizing the displacement controlled concept (not to be confused with the displacement based design methods) which is particularly relevant for low and moderate seismic regions for investigating the seismic performance of strength degraded structures. If the peak displacement demand (PDD) and the displacement capacity of the structure are known then the displacement based approach can be applied directly for assessing the performance of the structure. The seismic displacement demand is then simply compared with the displacement capacity to ensure that its gravity load carrying capacity is not compromised in the projected earthquake scenario.
A full scale testing was carried out under quasi-static conditions on a soft-storey building which was representative of existing building stock in low-moderate seismic regions to investigate the force-deformation relationship and drift capacity of soft-storey buildings. Data obtained from the full-scale experimental field studies on the force displacement behaviour of the building has been used as input into the nonlinear time history analyses to study the seismic response behavioral trends of soft-storey buildings.
A new simple methodology for estimating the peak displacement demand of inelastic nonlinear systems, which is based on the elastic displacement response spectra, was introduced. The major findings from the parametric studies shows that highest point on the elastic displacement response spectra can provide a conservative prediction of the maximum displacement demand of non-linear inelastic systems.
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Harouche, Isabelle Pacheco-Fernandes. "Simulation of shaped comb actuator for controlled displacement applications." 2005. http://hdl.handle.net/1993/20164.
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(6194160), Amine Nhila. "Pump Displacement Control in Steering On-Highway Commercial Vehicles." Thesis, 2019.
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Due to recent advances in sensor technology and the exponential increase in computation power of electronic control units (ECUs) along with their increasing affordability, active safety and vehicle automation have become major trends in the commercial vehicle industry. New regulations for increased safety are also a major driver behind the industry's increased interest in that topic. As a result, being a crucial part of vehicle automation, steering systems had to be adapted to enable Active Steering. Consequently, commercial vehicle steering designers introduced the concept of torque and angle overlay using an electric motor in series with the conventional hydraulic steering system. However, despite the fact that these systems are becoming more prevalent in the market, they still suffer from inefficiencies intrinsic to the conventional hydraulic steering system still being used. These inefficiencies are a result of
flow metering losses due to the use of control valves to regulate the pump flow output, as well as inside the steering gear with the use control valves to build assistance pressure.
In this research project, we investigate the potential use of the proven pump Displacement Control (DC) technology in steering on-highway commercial vehicles. DC pumps have been shown to signicantly improve system efficiency as they allow the removal of control valves typically used to regulate
ow [1]. Instead, the displacement of the pump can be directly controlled to vary the pump's flow rate and direction,
and thus eliminating throttling losses. The DC technology has been successfully used in a steer-by-wire conguration for an articulated frame steering vehicle and has been shown to signicantly improve efficiency and productivity, as well as result in a reduction in fuel consumption [2].
In this work, we propose a steer-by-wire system, using DC pump technology, for on-highway commercial vehicles, and present the dierent possible congurations in which it can be implemented. Moreover, the benets and drawbacks of the steer-by-wire system are researched and identied. Subsequently, the system is designed and validated in simulation, on laboratory test setup, as well as on a test vehicle to prove its feasibility.
Chief among the drawbacks of the steer-by-wire system is potential failures that can lead to the complete loss of the steering function of the vehicle. As a result, different possible fail-safe mechanisms are researched from which the most suitable ones are proposed to allow the steer-by-wire system to fail safely. Moreover, two of the proposed fail-safe mechanism are implemented onto the test vehicle to prove and validate their feasibility.
Furthermore, an alternative way of using displacement controlled pumps for active steering is be proposed. For this concept, we investigate the possibility of actively controlling the driver's steering effort by varying the pump displacement while maintaining the mechanical link between the steering wheel and the road wheels. If successful, this method will allow for a more efficient way of providing steering assistance as it does away with the conventional control valves used to build pressure and regulate pump flow, and thus eliminating throttling losses. This method has also the advantage of having an intrinsic fail-safe mechanism with manual steering being always possible should the hydraulic or electric systems fail.
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Lee, Wen-Chuan, and 李文全. "The Study of Position Control on Variable Displacement Pump-controlled Hydraulic Cylinder Systems Using Fuzzy Sliding Model Control." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/39516839988137076345.
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碩士國立臺灣科技大學
自動化及控制研究所
93
This paper is the first results of the series research of high response high efficiency pump-controlled hydraulic servo systems. This thesis aims to develop position control in variable displacement pump-controlled servo systems. For that, fuzzy sliding mode control (FSMC), which has the advantage of simple rule base and less computing time, is used. The experimental results show that the position control using FSMC in the variable displacement pump-controlled hydraulic servo system can reach the accuracy of 40m for 300mm stroke.
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Jalayeri, Ehsan. "Design and experimental evaluations of a pump-controlled hydraulic circuit." 2016. http://hdl.handle.net/1993/31143.
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This thesis presents a novel, low cost, high precision , and efficient design for an electro-hydrostatic circuit for single rod hydraulic cylinders. The design is the main contribution of candidate to fulfill the regiments of PhD degree. The challenge of existing deigns of electro-hydrostatic circuits for single-rod cylinders is using one pump to control the cylinder under switching (resistive-assistive) loads. The proposed circuit utilizes off-the-shelf industrial elements. It uses two counterbalance valves to manage switching loads and one on/off solenoid valve to redirect the differential flow of the single rod cylinder to tank. A set of simulation studies is conducted using Simhydraulic tools of Matlab in order to study performances of the proposed circuit and compare it with existing designs. Pump-controlled hydraulic circuit for double rod cylinders was developed and is widely used by industry. It is used as the benchmark for simulation studies. As well, the proposed circuit and two major existing pump-controlled circuits for single rod cylinders are compared to the benchmark circuit. Evaluations are conducted by comparing chamber pressure responses as well as pressure vs position of the cylinder end-effector for each individual circuit. Results indicate that the proposed circuit performed as well as the benchmark circuit by controlling pressures to both sides of the cylinder at the same time. Moreover, the load in the proposed circuit is more controllable compared to the benchmark circuit. Experimental results, obtained from the developed test rig, validate accuracy of the simulation model. Maximum steady state position error of 0.06 mm applications is experimentally observed when the test rig is tested under different loading conditions with various amplitudes and frequencies. The circuit consumes up to 20% of the energy that is required by a valve controlled circuit given the same sinusoidal tracking signal. The relative efficiency of the proposed circuit over a valve
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controlled circuit depends on the pattern and frequency of the tracking signal. In all the experiments, a simple proportional controller, which uses readings of a linear position transducer, is employed. The use of the proportional controller makes the proposed circuit easy to implement and shows it is good candidate for industrial applications. The accuracy of the position response of the proposed circuit indicates, it is a good candidate for robotic applications too.May 2016
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Lee, Cheng-Ling, and 李承霖. "Displacement Controller Design of Quadrotor." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/17366732757740381100.
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碩士淡江大學
航空太空工程學系碩士班
102
There are three parts presented in this thesis: derivation of quadrotor’s equation of motion and linearization, displacement controller design. In displacement controller design, used PD controller to control whole system. Finally, the open source flight control program in APM flight control board is rewritten to implement the displacement controller.
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Lucier, Peter E. "Design of a digital servo-electric pump/motor displacement controller." 1995. http://catalog.hathitrust.org/api/volumes/oclc/34102780.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1995.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 67-68).
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Yue-LinGuo and 郭岳霖. "Study on Redesign Energy-saving Variable Displacement Hydraulic Motor and Apply Self-tuning Fuzzy Sliding Mode Controller on Velocity and Position Control System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/83633195102676001721.
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Lin, Wen Yi, and 林文翌. "In Situ Photoacoustic Imaging of Carbon Nanotube Displacements in a Strained Polymer Matrix/Large-Scale Production of Ferromagnetic Nanorings by a Modified Hole-Mask Colloidal Lithography: Controlled Creation of Flux-Closure Vortex State." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/3s3e9d.
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