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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.
11

Προηγμένος ευρετικός έλεγχος πλοίου

Φώτου, Φώτιος 04 December 2012 (has links)
Στο πλαίσιο αυτής της διπλωματικής εργασίας μελετήθηκε το σύστημα του πλοίου και η απόκρισή του σε διάφορες εισόδους και αναπτύχθηκε κατάλληλη μέθοδο ελέγχου σύμφωνα με τη δεδομένη πειραματική διάταξη. Ο στόχος του ελεγκτή είναι από ένα αρχικό τυχαίο σημείο με αρχικό τυχαίο προσανατολισμό το πλοίο να προσεγγίσει ένα τελικό επιθυμητό σημείο και να σταθεροποιηθεί σε όσο δυνατόν μικρότερη απόσταση από αυτό.Για την επίτευξη αυτού του στόχου υλοποιήθηκε εμπειρικός ελεγκτής πρόσω δράσης. / This thesis adresses the control of a ship vessel. To accomplish this goal, the response of a model vessel to several control actions was recorded and a control algorithm based on this response was developed. The final goal was to approach a desired point on the horizontal plane having started from a random point and having random orientation at the starting point .
12

Performance improvement for stochastic systems using state estimation

Zhou, Yuyang January 2018 (has links)
Recent developments in the practice control field have heightened the need for performance enhancement. The designed controller should not only guarantee the variables to follow their set point values, but also ought to focus on the performance of systems like quality, efficiency, etc. Hence, with the fact that the inevitable noises are widely existing during industry processes, the randomness of the tracking errors can be considered as a critical performance to improve further. In addition, due to the fact that some controllers for industrial processes cannot be changed once the parameters are designed, it is crucial to design a control algorithm to minimise the randomness of tracking error without changing the existing closed-loop control. In order to achieve the above objectives, a class of novel algorithms are proposed in this thesis for different types of systems with unmeasurable states. Without changing the existing closed-loop proportional integral(PI) controller, the compensative controller is extra added to reduce the randomness of tracking error. That means the PI controller can always guarantee the basic tracking property while the designed compensative signal can be removed any time without affecting the normal operation. Instead of just using the output information as PI controller, the compensative controller is designed to minimise the randomness of tracking error using estimated states information. Since most system states are unmeasurable, proper filters are employed to estimate the system states. Based on the stochastic system control theory, the criterion to characterise the system randomness are valid to different systems. Therefore a brief review about the basic concepts of stochastic system control contained in this thesis. More specifically, there are overshoot minimisation for linear deterministic systems, minimum variance control for linear Gaussian stochastic systems, and minimum entropy control for non-linear and non-Gaussian stochastic systems. Furthermore, the stability analysis of each system is discussed in mean-square sense. To illustrate the effectiveness of presented control methods, the simulation results are given. Finally, the works of this thesis are summarised and the future work towards to the limitations existed in the proposed algorithms are listed.
13

DESIGN OF A HYDRAULIC ACTUATOR TEST STAND FOR NON-LINEAR ANALYSIS OF HYDRAULIC ACTUATOR SYSTEM

KRUTZ, JILL E. 11 October 2001 (has links)
No description available.
14

Reasonable reasoner: The influence of intervention strategy, system parameters and their representation on causal understanding

Bullemer, Beth Cristina January 2015 (has links)
No description available.
15

Decentralized probabilistic density control of swarm of autonomous agents with conflict avoidance constraints

Demir, Nazlı 01 October 2014 (has links)
This report describes a method to control the density distribution of a large number of autonomous agents. The approach is based on the fact that there are a large number of agents in the system, and hence the time evolution of the probabilistic density distribution of agents can be described as a Markov chain. The main contribution of this paper is the synthesis of a Markov matrix which will guide the multi-agent system density to a desired steady-state density distribution, in a probabilistic sense, while satisfying some motion and safety constraints. Also, an adaptive density control method based on real time density feedback is introduced to synthesize a time-varying Markov ma- trix, which leads to better convergence to the desired density distribution. Finally, a decentralized density computation method is described. This method guarantees that all agents will have a best, and common, density estimate in a finite, with an explicit bound, number of communication updates. / text
16

Identificação neuroanatômica de áreas cerebrais relacionadas à produção do canto em uma espécie de pássaro Suboscine da Amazônia (Myiozetetes cayanensis) / Neuroanatomical identification of cerebral areas related to the song production in a suboscine amazonian bird (Myiozetetes cayanensis).

Brito, Muriele Lobato 27 February 2018 (has links)
A comunidade cientifica, ao longo dos anos, comprovou aprendizagem vocal em tres ordens de aves (papagaios, beija-flores e passeriformes oscines). Contudo, mais recentemente, estudos feitos em tres especies de Suboscines, Sayornis Phoebe, Procnias tricarunculata e Chiroxiphia linearis revelaram a existencia de um sistema rudimentar do canto e/ou extensivas variacoes vocais quantitativas e qualitativas entre as populacoes reprodutivas, sugerindo que estas especies sao capazes de aprender o seu canto. Esta evidencia incita a investigacao de outras especies de passaros Suboscines, visto que a distincao entre passaros aprendizes e nao-aprendizes vocais nao e tao obvia quanto se pensava. Uma especie de passaro Suboscines amazonica, Myiozetetes cayanensis, desperta o nosso interesse devido a complexidade estrutural do canto em dueto que pode inferir alguma aprendizagem do canto. Com o intuito de identificar as regioes de controle da producao do canto nestes animais nos utilizamos diferentes tecnicas de marcacao celular coloracao de Nissl, hibridizacao in situ radioativa e injecao de tracadores neuronais; ferramentas neuroanatomicas estas que nos forneceram pistas sobre a presenca de areas cerebrais potencialmente envolvidas no sistema de controle do canto. Dos tres nucleos envolvidos na producao do canto, conseguimos identificar apenas o nucleo hipoglosso - porcao traqueosiringeal (NXIIts) e somente atraves da injecao do tracador neuronal CTB. Identificamos o NXIIts tanto em macho quanto em femeas e ao quantificar os dados verificamos que o volume deste nucleo e 2 vezes maior nos machos do que nas femeas, inferindo um possivel dimorfismo sexual. Ao compararmos o volume total de NXIIts entre o nosso animal experimental e uma especie de passaro Oscine, Taeniopigia guttata, verificamos que este nucleo foi quase 2 vezes maior em Taeniopigia guttata machos e femeas. Nao foram identificados nucleos telencefalicos que se assemelhassem ao HVC e ao RA de Oscines por meio de nenhuma das tecnicas utilizadas, o que nos leva a concluir que, em Myiozetetes cayanensis, nao haja sistema de controle do canto e que seu canto seja inato / Along the years vocal learning has been repeatedly demonstrated in three bird orders (parrots, hummingbirds and the oscine songbirds). But recently some studies developed in three spicies of suboscine birds, Sayornis Phoebe, Procnias tricarunculata e Chiroxiphia linearis, demonstrated the existence of a rudmentary song system and/or extensive qualitative and quantitative vocal variations between reproductives populations suggesting that these species are capable of learning their songs. This evidence instigates the investigation of other suboscine songbirds spieces, since the distinction between learning and non-learning vocal birds is not that clear as thought. An amazon uboscine bird, Myiozetetes cayanensis, has attracted our attention due to the structural complexity of its duet song that may imply some vocal learning. Therefore, we tried to identificate the song control regions in this animals by means of different technics: Nissl staining, radioactive in situ hibridization and injections of neural tracers; neuroanatomical tools that provided important clues of cerebral areas implicated in the song system control. We identified only one of the three nuclei involved in the controlling of song production, the NXIIts and only by the injection of the neural tracer CTB. The NXIIts was identified both in males and females. When we quantified the data, we observed that the NXIIts was 2 times larger in males than in females, indicating a possible sexual dimorphism. We also compared the total volume of NXIIts between our experimental animal and a oscine species, Taeniopygia guttata. The volume of NXIIts was almost 2 times larger both in males and females of Taeniopigia guttata. We didint identified any nucleus that guards some resemblence to the oscine HVC or RA through none of the techniques that we tested. Therefore, we can assume that Myiozetetes cayanensis have no song control system and that their song are inate
17

"Projeto e montagem de equipamento para controle de sistema de análise não destrutiva usando Radiação Nuclear" / DEVELOPMENT AND ASSEMBLY OF EQUIPMENT FOR NON DESTRUCTIVE ASSAY SYSTEM CONTROL USING NUCLEAR RADIATION

Melo, José Altino Tupinambá 26 September 2006 (has links)
Os Ensaios Não Destrutivos (END), são aplicados em testes de qualidade de componentes e de máquinas. Estes elementos não teriam um bom desempenho se fossem concebidos alheios à qualidade do projeto, aos materiais envolvidos, aos processos de fabricação e à metodologia de inspeção e manutenção. Um alto nível de tecnologia é aplicado com um objetivo específico, ou seja, à garantia da qualidade dos componentes e do bom funcionamento dessas máquinas, seja na indústria e na geração e conversão de energia, incluindo a nuclear. A globalização nos diversos ramos da indústria leva a um aumento na quantidade de projetos e produtos contextualmente multinacionais. Surgem, as seguintes questões: como assegurar que os componentes e os processos utilizados se disponhem de alto índice na qualidade? Como otimizar os métodos e os rocessos de teste de materiais para assegurar a isenção de defeitos que possam afetar o esempenho dos componentes? As respostas para as questões se encontram notadamente na aplicação dos END. A análise de materiais complexos (não homogêneos) por meio de END requer um estudo detalhado dos sinais de resposta dos sensores. Um sistema de medidas e controle de processos não destrutivos usando radiação gama ou beta, em função do material a ser analisado foi desenvolvido. Esse sistema envolve: (a) Interface de entrada/saída (Hardware) e (b) Interface gráfica (Software). Na análise não destrutiva faz-se a comparação do sinal proveniente do sensor com um sinal preestabelecido (Set Point) ou sinal de referência, o qual é ajustado na Interface de entrada/saída. Após o processamento geral, o sistema tomará a decisão de rejeitar ou não o material analisado. A Interface de entrada/saída é implementada por um equipamento eletrônico constituído pelo MCS51, com a finalidade de fornecer um meio físico para troca de nformações, via de comunicação serial RS232, entre o sensor e o microcomputador . A Interface gráfica (programa computacional) foi escrita em linguagem C++ visual. / Nondestructive Assay (NDA) is applied to machines and components quality tests. These elements would not have a good performance if they were conceived without concern about the mechanical project quality, used materials, manufacture processes and inspection and maintenance methodology. There are constant developments in high level of technology with the objective of guaranteeing the components quality and the good functioning of these machines, in the mechanics, naval, aeronautical, petrochemical and steel industry, energy and nuclear generation as well. The globalization in the industry lines is a fact, leading to an increase in the multinational projects and products. The following questions arise: how to assure the high quality of components and processes? How to optimize the test methods to assure that the materials do not have defects affecting the performance of the components? The answers to the questions above are found in the application of NDA. The complex materials analysis (inhomogeneous) using NDA requires a detailed study of the sensors response signal. In this work, a measure and control system of non destructive processes was developed, using a radioactive source with a defined energy in function of the material to be analyzed. This system involves: (a) Interface of input/output (I/O) (the Hardware) and (b) graphical Interface (Software). In the non destructive analysis, it is made the comparison of the signal proceeding from the sensor with a signal preset (Set Point) or analogical signal of reference (Base Line), which is adjusted in the I/O Interface. Analyzed the signal, the system will make the decision: (a) to reject or (b) to accept the analyzed material. The I/O Interface is implemented by electronic equipment with a MCS51. The purpose of this interface is to supply conditions to exchange information, using serial RS232, between the sensor and the microcomputer. The graphical Interface (software) is written in visual C++ language.
18

Projeto de sistemas modulares de controle para sistemas produtivos. / Project of modular control systems for production systems.

Nakamoto, Francisco Yastami 10 September 2008 (has links)
A competição no mercado globalizado, do ponto de vista do consumidor, aumentou consideravelmente a oferta de produtos e serviços, permitindo a escolha pela qualidade, preço, prazos e/ou disponibilidade. Entretanto, do ponto de vista das empresas, o desafio de atuar em um mercado saturado, dinâmico, competitivo e com aumento da demanda de produção orientado ao consumidor altera consideravelmente toda a estrutura da empresa. Desta forma, a flexibilidade torna-se um pré-requisito fundamental para que as empresas possam atuar neste mercado. Considerando-se o contexto apresentado, o objeto de estudo do presente trabalho são os Sistemas Produtivos Flexíveis (SPFs). Os SPFs são sistemas concebidos para atender às necessidades de um mercado dinâmico e competitivo. Isto causa complexidade no comportamento global desses sistemas exigindo diferentes propostas para o projeto de Sistemas de Controle de SPFs. A complexidade advém do fato de se perder a informação quanto ao pré-determinismo da seqüência de eventos que ocorrem no sistema global, além do fato de não existir previamente a definição de todos os processos de transporte com a designação prévia de todas as ordens de transporte que os transportadores presentes na planta devem executar. Neste contexto, o objetivo deste trabalho é apresentar como resultado uma proposta de sistema de controle modular para SPFs que atenda os requisitos de fluxo de informações envolvendo hierarquia e colaboração simultânea entre os módulos, respeitando a diversidade semântica presente na arquitetura. Apresenta-se então uma sistematização de projeto dos diversos módulos de controle e uma proposta de implementação de um algoritmo de designação dos transportadores para ser utilizado em tempo real permitindo a realização eficiente das atividades de transporte. / The competition in the globalized market increased considerably the demand for products and services to the customer point of view. However, the consumer\'s driven demand change the whole structure of the company. Thus, flexibility becomes an essential pre-requisite for companies to compete in the market. Considering the context presented, the object of study of this work is the Flexible Production System (FPS). The FPS must fulfill the needs on a dynamic and competitive market. This situation causes complexity in the overall performance of these systems, requiring different proposals for the design of the control systems. The complexity arises due to the fact that loses the information about the sequence of events that occur in the global system. Besides there is no previous exist definition for all processes of transport and prior designation for it. In this context, the objective of this work is to present a proposal for modular control systems to FPS that fits the requirements of information flow involving hierarchy and simultaneous collaboration between the modules. It will be presented systematization for the modular design of control as well as an implementation of an algorithm for designation of transport in real time leading to an efficient management of these activities.
19

"Projeto e montagem de equipamento para controle de sistema de análise não destrutiva usando Radiação Nuclear" / DEVELOPMENT AND ASSEMBLY OF EQUIPMENT FOR NON DESTRUCTIVE ASSAY SYSTEM CONTROL USING NUCLEAR RADIATION

José Altino Tupinambá Melo 26 September 2006 (has links)
Os Ensaios Não Destrutivos (END), são aplicados em testes de qualidade de componentes e de máquinas. Estes elementos não teriam um bom desempenho se fossem concebidos alheios à qualidade do projeto, aos materiais envolvidos, aos processos de fabricação e à metodologia de inspeção e manutenção. Um alto nível de tecnologia é aplicado com um objetivo específico, ou seja, à garantia da qualidade dos componentes e do bom funcionamento dessas máquinas, seja na indústria e na geração e conversão de energia, incluindo a nuclear. A globalização nos diversos ramos da indústria leva a um aumento na quantidade de projetos e produtos contextualmente multinacionais. Surgem, as seguintes questões: como assegurar que os componentes e os processos utilizados se disponhem de alto índice na qualidade? Como otimizar os métodos e os rocessos de teste de materiais para assegurar a isenção de defeitos que possam afetar o esempenho dos componentes? As respostas para as questões se encontram notadamente na aplicação dos END. A análise de materiais complexos (não homogêneos) por meio de END requer um estudo detalhado dos sinais de resposta dos sensores. Um sistema de medidas e controle de processos não destrutivos usando radiação gama ou beta, em função do material a ser analisado foi desenvolvido. Esse sistema envolve: (a) Interface de entrada/saída (Hardware) e (b) Interface gráfica (Software). Na análise não destrutiva faz-se a comparação do sinal proveniente do sensor com um sinal preestabelecido (Set Point) ou sinal de referência, o qual é ajustado na Interface de entrada/saída. Após o processamento geral, o sistema tomará a decisão de rejeitar ou não o material analisado. A Interface de entrada/saída é implementada por um equipamento eletrônico constituído pelo MCS51, com a finalidade de fornecer um meio físico para troca de nformações, via de comunicação serial RS232, entre o sensor e o microcomputador . A Interface gráfica (programa computacional) foi escrita em linguagem C++ visual. / Nondestructive Assay (NDA) is applied to machines and components quality tests. These elements would not have a good performance if they were conceived without concern about the mechanical project quality, used materials, manufacture processes and inspection and maintenance methodology. There are constant developments in high level of technology with the objective of guaranteeing the components quality and the good functioning of these machines, in the mechanics, naval, aeronautical, petrochemical and steel industry, energy and nuclear generation as well. The globalization in the industry lines is a fact, leading to an increase in the multinational projects and products. The following questions arise: how to assure the high quality of components and processes? How to optimize the test methods to assure that the materials do not have defects affecting the performance of the components? The answers to the questions above are found in the application of NDA. The complex materials analysis (inhomogeneous) using NDA requires a detailed study of the sensors response signal. In this work, a measure and control system of non destructive processes was developed, using a radioactive source with a defined energy in function of the material to be analyzed. This system involves: (a) Interface of input/output (I/O) (the Hardware) and (b) graphical Interface (Software). In the non destructive analysis, it is made the comparison of the signal proceeding from the sensor with a signal preset (Set Point) or analogical signal of reference (Base Line), which is adjusted in the I/O Interface. Analyzed the signal, the system will make the decision: (a) to reject or (b) to accept the analyzed material. The I/O Interface is implemented by electronic equipment with a MCS51. The purpose of this interface is to supply conditions to exchange information, using serial RS232, between the sensor and the microcomputer. The graphical Interface (software) is written in visual C++ language.
20

Design, Control and Motion Planning for a Novel Modular Extendable Robotic Manipulator

Yi, Hak 1979- 14 March 2013 (has links)
This dissertation discusses an implementation of a design, control and motion planning for a novel extendable modular redundant robotic manipulator in space constraints, which robots may encounter for completing required tasks in small and constrained environment. The design intent is to facilitate the movement of the proposed robotic manipulator in constrained environments, such as rubble piles. The proposed robotic manipulator with multi Degree of Freedom (m-DOF) links is capable of elongating by 25% of its nominal length. In this context, a design optimization problem with multiple objectives is also considered. In order to identify the benefits of the proposed design strategy, the reachable workspace of the proposed manipulator is compared with that of the Jet Propulsion Laboratory (JPL) serpentine robot. The simulation results show that the proposed manipulator has a relatively efficient reachable workspace, needed in constrained environments. The singularity and manipulability of the designed manipulator are investigated. In this study, we investigate the number of links that produces the optimal design architecture of the proposed robotic manipulator. The total number of links decided by a design optimization can be useful distinction in practice. Also, we have considered a novel robust bio-inspired Sliding Mode Control (SMC) to achieve favorable tracking performance for a class of robotic manipulators with uncertainties. To eliminate the chattering problem of the conventional sliding mode control, we apply the Brain Emotional Learning Based Intelligent Control (BELBIC) to adaptively adjust the control input law in sliding mode control. The on-line computed parameters achieve favorable system robustness in process of parameter uncertainties and external disturbances. The simulation results demonstrate that our control strategy is effective in tracking high speed trajectories with less chattering, as compared to the conventional sliding mode control. The learning process of BLS is shown to enhance the performance of a new robust controller. Lastly, we consider the potential field methodology to generate a desired trajectory in small and constrained environments. Also, Obstacle Collision Avoidance (OCA) is applied to obtain an inverse kinematic solution of a redundant robotic manipulator.

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