Dissertations / Theses on the topic 'Pitch variance'

Small scale wind turbines operating in an urban environment produce dismal amounts of power when compared to their expected output [1-4]. This is largely due to the gusty wind conditions found in an urban environment, coupled with the fact that the wind turbines are not designed for these conditions. A new concept of a Segmented Variable Pitch (SVP) wind turbine has been proposed, which has a strong possibility to perform well in gusty and variable wind conditions. This dissertation explains the concept of a SVP wind turbine in more detail and shows analytical and experimental results relating to this concept. Also, the potential benefits of the proposed concept are mentioned. The results from this dissertation show that this concept has potential with promising results on possible turbine blade aerofoil configurations. Scaled model tests were completed and although further design optimisation is required, the tests showed good potential for the SVP concept. Lastly a proof-of-concept full scale model was manufactured and tested to prove scalability to full size from concept models. Along with the proof-of-concept full scale model, a wireless control system (to control the blade segments) was developed and tested.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012.
Cataloged from department-submitted PDF version of thesis. This electronic version was submitted and approved by the author's academic department as part of an electronic thesis pilot project. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 101-106).
The aerospace community, particularly in academia, has seen a recent rise in the popularity of fixed-pitch quadrotor helicopters. The fixed-pitch quadrotor is popular largely because of its mechanical simplicity relative to other hovering aircraft. This simplicity, however, places fundamental limits on the achievable actuator bandwidth and the types of maneuvers possible to fly. This thesis explores the extent to which the addition of variable-pitch propellers to a quadrotor helicopter overcomes these limitations. A detailed analysis of the potential benefits of variable-pitch propellers over fixed-pitch propellers for a quadrotor is presented. This analysis is supported with experimental testing to show that variable-pitch propellers, in addition to allowing for efficient generation of negative thrust, substantially increase the maximum rate of thrust change. A nonlinear, quaternion-based control algorithm is presented for controlling the quadrotor. An accompanying trajectory generation method is detailed with an optimization routine for finding minimum-time paths through waypoints. The control law and trajectory generation algorithms are implemented in simulation and on a custom variable-pitch quadrotor. The quadrotor attitude control is performed on the vehicle using a custom autopilot. Position and attitude measurements are made with an off-board motion capture system. Several flight tests are shown with a particular emphasis on the benefits of a variable-pitch qaudrotor over a standard fixed-pitch quadrotor for performing aggressive and aerobatics maneuvers. To the best of the author's knowledge, this work marks the first documented, autonomous variable-pitch quadrotor built for agile and aggressive flight.
by Mark Johnson Cutler.
S.M.

Vertical-axis wind turbines do not need to be oriented to the wind direction and offer direct rotary output to a ground-level load, making them particularly suitable for water pumping, heating, purification and aeration, as well as stand-alone electricity generation. The use of high-efficiency Darrieus turbines for such applications is virtually prohibited by their inherent inability to self-start. The provision of blade-articulation (variable-pitch blades) has been demonstrated by a number of researchers to make Darrieus turbines self-starting. One aim of this thesis is to evaluate the various concepts manifested in the numerous specific passive variable-pitch designs appearing in the literature, often without theoretical analysis. In the present work, two separate mathematical models have been produced to predict the performance of passive variable-pitch Darrieus-type turbines. A blade-element/momentum theory model has been used to investigate the relationships between the key parameter values and turbine steady-state performance. A strategy for parameter selection has been developed on the basis of these results. A free vortex wake model for passive variable-pitch turbines has been developed, allowing the study of unsteady performance. Significant reduction of average ef- ficiency in a turbulent wind is predicted for a Darrieus turbine. The improved low-speed torque of passive variable-pitch turbines is predicted to significantly improve turbulent wind performance. Two new design concepts for passive variable-pitch turbines are presented that are intended to allow greater control of blade pitch behaviour and improved turbulent wind performance. A prototype turbine featuring these design concepts has been designed, constructed and tested in the wind tunnel. As part of this testing, a technique has been developed for measuring the pitch angle response of one of the turbine blades in operation. This allows comparison of predicted and measured pitch histories and gives insight into the performance of turbines of this type. Results have demonstrated the usefulness of the mathematical models as design tools and have indicated the potential of one of the new design concepts in particular to make a vertical axis wind turbine self-starting.

The variable pitch quadrotor is not a new concept but has been largely ignored in small unmanned aircraft, unlike the fixed pitch quadcopter which is controlled only by changing the RPM of the motors and only has about 30 minutes of total flight time. The variable pitch quadrotor can be controlled either by the change of the motor RPM or rotor blade pitch angle or by the combination of both. This gives the variable pitch quadrotor potential advantages in payload, maneuverability and long endurance flight. This research is focused on the design methodology for a variable pitch quadrotor using a single motor with potential applications for a long endurance flight. This variable pitch quadcopter uses a single power plant to power all four rotors through a power transmission system. All four rotors have the same rpm but vary the blade pitch angle to control its attitude in the air. A proof of concept variable pitch quadcopter is developed for testing the drivetrain mechanism on the vehicle and evaluating performance of the vehicle through numbers of testing.

One approach to achieve non-mechanical beam steering is to use variable diffraction devices, whose intensity and direction of the outgoing diffractive orders can be actively (typically electronically) altered by modifying the optical properties of the device. Devices with sub-micron features are of particular interest when working with visible wavelengths, since such gratings can, when not activated, produce only an undeflected beam as the output and, when activated, produce diffractive orders at large deflection angles that appear and disappear entirely. Such sub-micron pitch variable diffraction gratings can be achieved by electrophoretically moving dye ions into and out of appropriately patterned transparent electrically-conductive nanoporous electrodes. This study aimed to explore their potential for use in practical devices. One significant technical hurdle associated with these devices has been the irreversible electrochemical reactions that can be induced with an applied voltage difference between the two electrodes exceeding a critical value on the order of 1 V. These reactions are undesirable as they limit the lifetime of the device. However, it was observed that when operating within such a voltage limit the optical response time is undesirably long - on the order of seconds. To better optimize the lifetime and response time of these devices, an electron tunneling model of the electrochemical reaction threshold was developed and verified. This enabled the use of a high speed drive circuit that was able to improve the response time by a factor of 50 without compromising the lifetime of the device. A prototype grating with nanoporous zinc antimonate electrodes and methylene blue dye-methanol solution was fabricated using focused ion beam milling. Modulation of a diffractive order was observed with this prototype, where the exit beam geometry was in good agreement with the model. The diffractive efficiency of the diffractive order was observed to be 3.9×10-3 when in the charged state and 7.9×10-4 when in the uncharged state with an optical switching time of 250 ms. These observations demonstrated the potential of this type of device to achieve large angular deflection and fast operating speed for non-mechanical beam steering applications.

In this study, a variable pitch axial flow fan is designed and analysed for Ankara Wind Tunnel (AWT). In order to determine the loss caharacteristics of AWT, an algorithm is developed and the results are validated. Also some pressure and velocity measurements are made at the fan section to find the losses experimentally. After completion of the fan design, analyses are made at different volumetric flowrates and blade angles including the design point and the performance characteristics of the fan are obtained and thereafter the operating range of the tunnel is deterimened.

This research work carried out to investigate the performance of variable helix and pitch cutting tools on the chatter vibration of Inconel 718. The results show that variable helix and pitch cutting tool are able to enhance the stability in the milling process of Inconel 718. In addition, it also revealed that tool corner geometry plays a significant role in reducing chatter vibration, improving surface roughness and conserving longer tool life.

A stall-regulated wind turbine with fixed-speed operation provides a configuration which is one of the cheapest and simplest forms of wind generation and configurations. This type of turbine, however, is non-optimal at low winds, stresses the component structure and gives rise to significant power peaks during early stall conditions at high wind speeds. These problems can be overcome by having a properly designed generator speed control. Therefore, to track the maximum power locus curve at low winds, suppress the power peaks at medium winds, limit the power at a rated level at high winds and obtain a satisfactory power-wind speed curve performance (that closely resembles the ideal power-wind speed curve) with minimum stress torque simultaneously over the whole range of the wind speed variations, the availability of active control is vital. The main purpose of this study is to develop an internal model control (IMC) design for the squirrel-cage induction generator (SCIG), coupled with a full-rated power converter of a small (25 kW), stall-regulated, variable-speed wind-turbine (SRVSWT) system, which is subject to variations in the generator speed, electromagnetic torque and rotor flux. The study was done using simulations only. The objective of the controller was to optimise the generator speed to maximise the active power generated during the partial load region and maintain or restrict the generator speed to reduce/control the torque stress and the power-peaking between the partial and full load regions, before power was limited at the rated value of 25 kW at the full load region. The considered investigation involved estimating the proportional-integral (PI) and integral-proportional (IP) controllers parameter values used to track the stator-current producing torque, the rotor flux and the angular mechanical generator speed, before being used in the indirect vector control (IVC) and the sensorless indirect vector control (SLIVC) model algorithms of the SCIG system. The design of the PI and IP controllers was based on the fourth-order model of the SCIG, which is directly coupled to the full-rated power converter through the machine stator, whereas the machine rotor is connected to the turbine rotor via a gearbox. Both step and realistic wind speed profiles were considered. The IMC-based PI and IP controllers (IMC-PI-IP) tuning rule was proven to have smoothened the power curve and shown to give better estimation results compared to the IMC-based PI controllers (IMC-PI), Ziegler-Nichols (ZN) and Tyreus-Luyben (ZN) tuning rules. The findings also showed that for the SRVSWT system that employed the IVC model algorithm with the IMC-PI-IP tuning rule, considering the application of a maintained/constant speed (CS) strategy at the intermediate load region is more profitable than utilizing SRVSWT with the modified power tracking (MoPT) strategy. Besides that, the finding also suggested that, for the IMC-PI-IP approach, the IVC does provide better power tracking performance than the SLIVC model algorithm.

This thesis focuses on the optimization of the electric aircraft propeller in order to increaseflight performance. Electric aircraft have limited energy, particularly the electricmotor torque compared to the fuel engine torque. For that, redesign of the propeller forelectric aircraft is important in order to improve the propeller efficiency. The airplanepropeller theory for Glauert is selected as a design method and incorporated with Brattimprovements of the theory. Glauert theory is a combination of the axial momentum andblade element theory. Pipistrel Alpha Electro airplane specifications have been chosen asa model for the design method. Utilization of variable pitch propeller and the influence ofnumber of blades has been investigated. The obtained design results show that the variablepitch propellers at cruise speed and altitude 3000 m reducing the power consumptionby 0.14 kWh and increase the propeller efficiency by 0.4% compared to the fixed pitchpropeller. Variable pitch propeller improvement was pretty good for electric aircraft. Theoptimum blade number for the design specifications is 3 blades.
Denna rapport har som fokus att optimera propellern på ett eldrivet flygplan för att förbättraflygprestationen. Eldrivna flygplan har begränsad energi, i synnerhet motorns vridmomenti jämförelse med bränslemotorns vridmoment. Därav behöver propellern designas om föratt uppnå en större verkningsgrad i propellern. Glauerts teori om flygplanspropellrar haranvänts som metod för designen där vissa modifieringar i teorin har tillämpats enligt Brattför att förbättra teorin. Glauerts teori är en kombination mellan axiell momentum- ochbladelement teori. Specifikationerna för Pipistrel Alpha Electro flygplan har använts sommodell i design metoden. Utnyttjande av propeller med justerbara bladvinklar samt antalblads påverkan har undersökts. De erhållna designresultaten visade att propellern medjusterbara bladvinklar vid planflykt på 3000 m höjd har sparat 0,14 kWh samt ökat propellernsverkningsgrad med 0,4% jämfört med propellern med icke justerbara bladvinklar.Propeller med justerbara stigning var lämplig för elflygplan. Det optimala antalet blad fördesignspecifikationerna är 3 blad.

Les études, menées en collaboration entre la société VALEOL et le laboratoire IMS, proposent des solutions pour optimiser la production et le fonctionnement d'une éolienne. Il s’agit de travailler sur les lois de commande du système ou des sous-systèmes en utilisant la commande CRONE, répondant à un besoin de robustesse. Chaque étude met en avant des aspects de modélisation, d’identification et de synthèse de lois de commande avant mises en application au travers de simulations ou d’essais sur modèles réduits et taille réelle.Le chapitre 1 donne une vision d’ensemble des problématiques traitées dans ce manuscrit, à l’aide d’états de l’art et de remise dans le contexte économique et industriel de 2013.Le chapitre 2 introduit la commande CRONE pour la synthèse de régulateurs robustes. Cette méthodologie est utilisée pour réaliser l’asservissement de la vitesse de rotation d’une éolienne à vitesse variable, présentant une architecture innovante avec un variateur de vitesse mécanique et génératrice synchrone.Le chapitre 3 établit la comparaison de trois nouveaux critères d’optimisation pour la méthodologie CRONE. Le but est de réduire sa complexité et de faciliter sa manipulation par tout utilisateur. Les résultats sur les différents critères sont obtenus par simulations sur un exemple académique, puis sur un modèle d’éolienne de type MADA.Le chapitre 4 porte sur la réduction des charges structurelles transmises par le vent à l’éolienne. Il est question d’une amélioration du contrôle de l’angle de pitch par action indépendante sur chaque pale en fonction de la position du rotor ou encore des perturbations liées au ventLe chapitre 5 est consacré à la conception d’un système d’antigivrage et dégivrage d’une pale dans le cadre d’un projet Aquitain. Après modélisation et identification du procédé, la commande CRONE est utilisée pour réguler la température d’une peinture polymère chauffante sous alimentation électrique disposée sur les pales. L’étude est complétée par la mise en place d’un observateur pour la détection de présence de givre
The research studies, in collaboration with VALEOL and IMS laboratory, propose several solutions to optimize the production and the efficiency of a wind turbine. The general theme of the work is based on control laws of the system or subsystems using the CRONE robust design. Each part highlights aspects of modeling, system identification and design before simulations or tests of scale and full size models. Chapter 1 provides an overview of the issues discussed in this manuscript, using states of the art and precisions on the industrial and economic context of 2013.Chapter 2 introduces the CRONE command for robust design. It is used to achieve the control of the rotation speed of a variable speed wind turbine, with an innovative architecture - mechanical variable speed solution and synchronous generator.Chapter 3 makes a comparison of three new optimization criteria for CRONE design. The aim is to reduce the methodology complexity and to facilitate handling by any user. The results are obtained through simulations on an academic example, then with a DFIG wind turbine model. Chapter 4 focuses on the reduction of structural loads transmitted by the wind on the turbine. It is about better control of the pitch angle by individual pitch control, depending on the rotor position or wind disturbances.Chapter 5 deals with the design of an anti-icing/de-icing system for blades. After the modeling and identification steps, the CRONE design is used to control the temperature of a heating coating disposed on the blades. An observer is finally designed to detect the presence of ice

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CNPq
Um controle para auxílio do controle de frequência é projetado utilizando um método baseado em lógica fuzzy e no controle do ângulo de passo de turbinas eólicas de velocidade variável. O controle visa que as turbinas eólicas operem abaixo do seu valor nominal, estando sempre prontas para aumentar sua geração no caso de evento na rede elétrica, contribuindo para o controle de frequência. Com os esforços para converter tanta energia quanto seja possível com o vento disponível, a potência desperdiçada pela maioria dos controles estudados para elaboração desta tese vale a pena em relação aos benefícios do controle de frequência em sistemas com grande penetração das usinas eólicas, proporcionando a participação da energia eólica nos serviços ancilares. Ressaltando que a introdução de qualquer nova tecnologia de geração no sistema deve ser feita de modo que seja compatível com os princípios operacionais do sistema existente. O controle fuzzy de potência foi desenvolvido no Matlab®/Simulink e permite o bom funcionamento da turbina eólica utilizando uma metodologia alternativa aos controles clássicos. Com isto foi desenvolvido o controle de frequência também baseado em lógica fuzzy. Como grande vantagem do controle fuzzy destaca-se sua fácil adaptação a outros modelos de turbina que utilizem o controle de pitch (turbinas eólicas de velocidade variável), uma vez que o algoritmo é o mesmo, havendo a necessidade apenas de fazer testes para adaptação das faixas de operação do controle.
A control to support the frequency control is designed using a method based on fuzzy logic and pitch angle control in variable speed wind turbines. The control aims that some wind turbines operate below their rated value (derated or deloaded), being always ready to increase their generation in case of some event in the power grid, contributing to the frequency control. With efforts to convert as much energy as possible with the available wind, the power wasted by most controls studied in this work worth of the benefits of frequency control in systems with high power plants penetration, providing wind power to participate on ancillary services. Recalling that the introduction of any new generation technology into the system must be made in a way that is compatible with the operating principles of the existing system. The fuzzy control developed in Matlab®/Simulink for power control enables a suitable operation of the wind turbine using an alternative methodology to the classic controls, it was developed the frequency control also based on fuzzy logic. The fuzzy control great advantage highlight is its easy adaptation to other turbine design which use pitch control (variable speed wind turbines), since the algorithm is the same, just by doing tests for adjustment of the control operation ranges.

Le travail de cette thèse s’inscrit dans la commande non linéaire des structures éoliennes. Le premier objectif de cette thèse est la commande d’une éolienne standard fonctionnant à vitesse et angle de calage variables. Les stratégies de commande proposées permettant de commander l’éolienne dans des zones de fonctionnement différentes (optimisation et limitation de la puissance produite). Le deuxième objectif consiste en la conception de commande d’une nouvelle structure d’éolienne à double rotor. L’originalité de cette structure réside dans le fait qu’elle peut pivoter face au vent sans actionneur dédié, et ce grâce à la rotation libre du bras portant les deux éoliennes. Deux architectures de commande sont proposées afin d’orienter la structure face au vent : l’une crée un différentiel des angles de calage des pales des deux éoliennes, l’autre agissant via la différence de puissance produite par les deux génératrices. Étant donné que l’environnement est incertain et fortement perturbé (variations du vent, erreurs de modélisation, bruits de mesure), des lois de commande non linéaires robustes sont proposées. L’efficacité des stratégies de commande a été vérifiée selon différents scénarios
This work deals the nonlinear control of wind turbine structures. The first objective is the design of control laws of a standard wind turbine with variable speed-variable pitch angle. The proposed control strategies allow controlling the wind turbine indifferent operating areas (optimization and powerlimitation).The second objective consists in controlling a new structure of twin wind turbines. The originality of this structure lies in the fact that it can rotate face the wind without using a dedicated actuator, thanks to the free rotation of the arm carrying the wind turbines. Two control architectures are proposed in order to ensure the structure face the wind : pitch angles differential and the produced power difference. Given that the environment is uncertain (windvariations, modeling errors, noise), robust nonlinear control laws are proposed for a multiple objectives. The efficiency of the control strategies have been carried out according to several scenarios

: Les travaux présentés dans cette thèse traitent du contrôle de systèmes dynamiques soumis à des excitations harmoniques et transitoires en utilisant des absorbeurs de type Nonlinear Energy Sink (NES). Plusieurs aspects ont été développés : la conception et la réalisation d'un nouveau design pour le NES cubique, l'étude de la location et du transfert irréversible d'énergie sur un NES bistable et le développement d'un critère de conception pour un NES à Vibro-Impact (VI). Dans un premier temps, un critère de conception est proposé pour le NES à raideur cubique. Le design proposé est basé sur des ressorts coniques ou des ressorts à pas variable. Un mécanisme à raideur négative est aussi introduit pour supprimer la partie linéaire et avoir une raideur cubique pure. Dans un deuxième temps, le concept du NES est validé expérimentalement par des essais statiques et des essais dynamiques. Une analyse de sensibilité est aussi menée sur la longueur des ressorts précontraints, elle dénote parfois un état bistable de l'oscillateur. Ensuite, le NES bistable ainsi obtenu est étudié plus en détail. Ce type d'absorbeur s'avère être très robuste pour différents types d’excitation. Des études expérimentales sont aussi menées afin d'explorer le comportement dynamique. Enfin, un critère de conception est proposé pour le NES à Vibro-Impact. Des calculs analytiques détaillés sont proposés pour contrôler les vibrations sous différentes excitations. L'étude expérimentale montre une bonne cohérence avec les résultats théoriques
The work presented in this thesis deals with the passive control of dynamics systems subjected to harmonic and transient excitations using a Nonlinear Energy Sink (NES). Several research aspects have been developed: design theory and experimental study of a novel NES, efficient Targeted Energy Transfer (TET) of bistable NES and design criteria for optimally tuned Vibro-Impact (VI) NES. Firstly, a design criterion intended to provide optimal nonlinear stiffness is proposed. Then a novel design of NES system yielding cubic stiffness with conical springs or variable pitch springs and negative stiffness mechanism is developed. Secondly, the experimental procedures for static and dynamic test are presented and applied to validate the concept of NES system. Then a sensitivity analysis is performed with respect to the pre-compressed length of springs. Thirdly, the optimal design of the above device with negative stiffness (termed as bistable NES) is studied. This type of NES is proved to work robustly for different types of excitation, and experimental study of semi-active control are explored. Finally, design criteria for optimally tuned VI NES are studied. Detailed analytical calculations of clearance to control the vibration under different excitations are proposed. A good correspondence between theoretical and experimental results is observed

L'amélioration des performances des chaînes de conversion dédiées à la récupération d'énergie par les hydroliennes est un point particulièrement important pour rendre cette ressource économiquement attractive. La minimisation du coût de l'énergie produite passe nécessairement par une amélioration des performances de la chaîne de conversion électromécanique et une réduction des coûts de maintenance et de production des éléments la constituant. Dans ce contexte particulier, les génératrices à aimants permanents apparaissent particulièrement intéressantes dans la mesure où elles sont bien adaptées à un fonctionnement à basse vitesse et à fort couple. Ceci permet d'éliminer des systèmes mécaniques très complexes, encombrants et exigeants en maintenance, tels que le multiplicateur de vitesse et/ou le système d'orientation des pales. L'objectif de cette thèse est d’explorer un certain nombre de pistes concernant les outils, les concepts et les règles de conception à mettre en oeuvre pour dimensionner une génératrice associée en entraînement direct à une turbine hydrolienne à pas fixe. Les outils mis au point dans ces travaux englobent des modèles multi-physiques intégrés dans une démarche de conception qui se veut la plus globale possible. Cette méthodologie tient compte de la caractéristique de la ressource (courants de marées), de celle de la turbine (hélice), des spécifications de la génératrice à aimants permanents, de la mise en oeuvre d’une stratégie de pilotage associant MPPT et limitation de puissance par défluxage à fort courants de marées, en plus des contraintes liées au convertisseur. L'environnement de conception développé est basé sur un couplage des modèles dans une procédure d'optimisation. Les résultats obtenus mettent en lumière les points clés associés au développement d’une telle génératrice pour un contexte hydrolien
The improvements of marine current turbines drive train are key features to ensure safe operation and to make tidal energy resource cost-attractive. In this context, eliminating mechanical systems that demand high-level of maintenance can be an interesting way to improve the global behavior of tidal turbines. For that purposes, the presented studies focus on design methodologies and concepts of direct-driven generators associated with fixed-pitch turbines. The proposed designs are based on multiphysics models of the generator that are integrated in an optimization process taking into account the drive train environment. For these reasons, several models have been integrated into a global design strategy in order to find solutions that improve marine current turbines performances. This strategy is based on the use of an optimization process that combines electromagnetic model, thermal model, turbine performances model, and tidal resource velocity profile. This methodology integrates also an efficient control strategy based on a maximum power point tracking (MPPT) approach at low tidal speed and a flux-weakening power limitation control at high tidal speed. This control at high tidal velocities is in this work achieved by considering only the generator electrical control without using blade pitching systems. The obtained results highlight trends that could lead to an improvement of the design and they help designers to set relevant technological choices in order to ensure significant cost reduction and highly improve the reliability of marine current turbines

This thesis addresses several shortcomings on the current state of the art methodologies in music information retrieval (MIR). In particular, it proposes several computational approaches to automatically analyze and describe music scores and audio recordings of Ottoman-Turkish makam music (OTMM). The main contributions of the thesis are the music corpus that has been created to carry out the research and the audio-score alignment methodology developed for the analysis of the corpus. In addition, several novel computational analysis methodologies are presented in the context of common MIR tasks of relevance for OTMM. Some example tasks are predominant melody extraction, tonic identification, tempo estimation, makam recognition, tuning analysis, structural analysis and melodic progression analysis. These methodologies become a part of a complete system called Dunya-makam for the exploration of large corpora of OTMM. The thesis starts by presenting the created CompMusic Ottoman- Turkish makam music corpus. The corpus includes 2200 music scores, more than 6500 audio recordings, and accompanying metadata. The data has been collected, annotated and curated with the help of music experts. Using criteria such as completeness, coverage and quality, we validate the corpus and show its research potential. In fact, our corpus is the largest and most representative resource of OTMM that can be used for computational research. Several test datasets have also been created from the corpus to develop and evaluate the specific methodologies proposed for different computational tasks addressed in the thesis. The part focusing on the analysis of music scores is centered on phrase and section level structural analysis. Phrase boundaries are automatically identified using an existing state-of-the-art segmentation methodology. Section boundaries are extracted using heuristics specific to the formatting of the music scores. Subsequently, a novel method based on graph analysis is used to establish similarities across these structural elements in terms of melody and lyrics, and to label the relations semiotically. The audio analysis section of the thesis reviews the state-of-the-art for analysing the melodic aspects of performances of OTMM. It proposes adaptations of existing predominant melody extraction methods tailored to OTMM. It also presents improvements over pitch-distribution-based tonic identification and makam recognition methodologies. The audio-score alignment methodology is the core of the thesis. It addresses the culture-specific challenges posed by the musical characteristics, music theory related representations and oral praxis of OTMM. Based on several techniques such as subsequence dynamic time warping, Hough transform and variable-length Markov models, the audio-score alignment methodology is designed to handle the structural differences between music scores and audio recordings. The method is robust to the presence of non-notated melodic expressions, tempo deviations within the music performances, and differences in tonic and tuning. The methodology utilizes the outputs of the score and audio analysis, and links the audio and the symbolic data. In addition, the alignment methodology is used to obtain score-informed description of audio recordings. The scoreinformed audio analysis not only simplifies the audio feature extraction steps that would require sophisticated audio processing approaches, but also substantially improves the performance compared with results obtained from the state-of-the-art methods solely relying on audio data. The analysis methodologies presented in the thesis are applied to the CompMusic Ottoman-Turkish makam music corpus and integrated into a web application aimed at culture-aware music discovery. Some of the methodologies have already been applied to other music traditions such as Hindustani, Carnatic and Greek music. Following open research best practices, all the created data, software tools and analysis results are openly available. The methodologies, the tools and the corpus itself provide vast opportunities for future research in many fields such as music information retrieval, computational musicology and music education.
Esta tesis aborda varias limitaciones de las metodologías más avanzadas en el campo de recuperación de información musical (MIR por sus siglas en inglés). En particular, propone varios métodos computacionales para el análisis y la descripción automáticas de partituras y grabaciones de audio de música de makam turco-otomana (MMTO). Las principales contribuciones de la tesis son el corpus de música que ha sido creado para el desarrollo de la investigación y la metodología para alineamiento de audio y partitura desarrollada para el análisis del corpus. Además, se presentan varias metodologías nuevas para análisis computacional en el contexto de las tareas comunes de MIR que son relevantes para MMTO. Algunas de estas tareas son, por ejemplo, extracción de la melodía predominante, identificación de la tónica, estimación de tempo, reconocimiento de makam, análisis de afinación, análisis estructural y análisis de progresión melódica. Estas metodologías constituyen las partes de un sistema completo para la exploración de grandes corpus de MMTO llamado Dunya-makam. La tesis comienza presentando el corpus de música de makam turcootomana de CompMusic. El corpus incluye 2200 partituras, más de 6500 grabaciones de audio, y los metadatos correspondientes. Los datos han sido recopilados, anotados y revisados con la ayuda de expertos. Utilizando criterios como compleción, cobertura y calidad, validamos el corpus y mostramos su potencial para investigación. De hecho, nuestro corpus constituye el recurso de mayor tamaño y representatividad disponible para la investigación computacional de MMTO. Varios conjuntos de datos para experimentación han sido igualmente creados a partir del corpus, con el fin de desarrollar y evaluar las metodologías específicas propuestas para las diferentes tareas computacionales abordadas en la tesis. La parte dedicada al análisis de las partituras se centra en el análisis estructural a nivel de sección y de frase. Los márgenes de frase son identificados automáticamente usando uno de los métodos de segmentación existentes más avanzados. Los márgenes de sección son extraídos usando una heurística específica al formato de las partituras. A continuación, se emplea un método de nueva creación basado en análisis gráfico para establecer similitudes a través de estos elementos estructurales en cuanto a melodía y letra, así como para etiquetar relaciones semióticamente. La sección de análisis de audio de la tesis repasa el estado de la cuestión en cuanto a análisis de los aspectos melódicos en grabaciones de MMTO. Se proponen modificaciones de métodos existentes para extracción de melodía predominante para ajustarlas a MMTO. También se presentan mejoras de metodologías tanto para identificación de tónica basadas en distribución de alturas, como para reconocimiento de makam. La metodología para alineación de audio y partitura constituye el grueso de la tesis. Aborda los retos específicos de esta cultura según vienen determinados por las características musicales, las representaciones relacionadas con la teoría musical y la praxis oral de MMTO. Basada en varias técnicas tales como deformaciones dinámicas de tiempo subsecuentes, transformada de Hough y modelos de Markov de longitud variable, la metodología de alineamiento de audio y partitura está diseñada para tratar las diferencias estructurales entre partituras y grabaciones de audio. El método es robusto a la presencia de expresiones melódicas no anotadas, desviaciones de tiempo en las grabaciones, y diferencias de tónica y afinación. La metodología utiliza los resultados del análisis de partitura y audio para enlazar el audio y los datos simbólicos. Además, la metodología de alineación se usa para obtener una descripción informada por partitura de las grabaciones de audio. El análisis de audio informado por partitura no sólo simplifica los pasos para la extracción de características de audio que de otro modo requerirían sofisticados métodos de procesado de audio, sino que también mejora sustancialmente su rendimiento en comparación con los resultados obtenidos por los métodos más avanzados basados únicamente en datos de audio. Las metodologías analíticas presentadas en la tesis son aplicadas al corpus de música de makam turco-otomana de CompMusic e integradas en una aplicación web dedicada al descubrimiento culturalmente específico de música. Algunas de las metodologías ya han sido aplicadas a otras tradiciones musicales, como música indostaní, carnática y griega. Siguiendo las mejores prácticas de investigación en abierto, todos los datos creados, las herramientas de software y los resultados de análisis está disponibles públicamente. Las metodologías, las herramientas y el corpus en sí mismo ofrecen grandes oportunidades para investigaciones futuras en muchos campos tales como recuperación de información musical, musicología computacional y educación musical.
Aquesta tesi adreça diverses deficiències en l’estat actual de les metodologies d’extracció d’informació de música (Music Information Retrieval o MIR). En particular, la tesi proposa diverses estratègies per analitzar i descriure automàticament partitures musicals i enregistraments d’actuacions musicals de música Makam Turca Otomana (OTMM en les seves sigles en anglès). Les contribucions principals de la tesi són els corpus musicals que s’han creat en el context de la tesi per tal de dur a terme la recerca i la metodologia de alineament d’àudio amb la partitura que s’ha desenvolupat per tal d’analitzar els corpus. A més la tesi presenta diverses noves metodologies d’anàlisi computacional d’OTMM per a les tasques més habituals en MIR. Alguns exemples d’aquestes tasques són la extracció de la melodia principal, la identificació del to musical, l’estimació de tempo, el reconeixement de Makam, l’anàlisi de la afinació, l’anàlisi de la estructura musical i l’anàlisi de la progressió melòdica. Aquest seguit de metodologies formen part del sistema Dunya-makam per a la exploració de grans corpus musicals d’OTMM. En primer lloc, la tesi presenta el corpus CompMusic Ottoman- Turkish makam music. Aquest inclou 2200 partitures musicals, més de 6500 enregistraments d’àudio i metadata complementària. Les dades han sigut recopilades i anotades amb ajuda d’experts en aquest repertori musical. El corpus ha estat validat en termes de d’exhaustivitat, cobertura i qualitat i mostrem aquí el seu potencial per a la recerca. De fet, aquest corpus és el la font més gran i representativa de OTMM que pot ser utilitzada per recerca computacional. També s’han desenvolupat diversos subconjunts de dades per al desenvolupament i evaluació de les metodologies específiques proposades per a les diverses tasques computacionals que es presenten en aquest tesi. La secció de la tesi que tracta de l’anàlisi de partitures musicals se centra en l’anàlisi estructural a nivell de secció i de frase musical. Els límits temporals de les frases musicals s’identifiquen automàticament gràcies a un metodologia de segmentació d’última generació. Els límits de les seccions s’extreuen utilitzant un seguit de regles heurístiques determinades pel format de les partitures musicals. Posteriorment s’utilitza un nou mètode basat en anàlisi gràfic per establir semblances entre aquest elements estructurals en termes de melodia i text. També s’utilitza aquest mètode per etiquetar les relacions semiòtiques existents. La següent secció de la tesi tracta sobre anàlisi d’àudio i en particular revisa les tecnologies d’avantguardia d’anàlisi dels aspectes melòdics en OTMM. S’hi proposen adaptacions dels mètodes d’extracció de melodia existents que s’ajusten a OTMM. També s’hi presenten millores en metodologies de reconeixement de makam i en identificació de tònica basats en distribució de to. La metodologia d’alineament d’àudio amb partitura és el nucli de la tesi. Aquesta aborda els reptes culturalment específics imposats per les característiques musicals, les representacions de la teoria musical i la pràctica oral particulars de l’OTMM. Utilitzant diverses tècniques tal i com Dynamic Time Warping, Hough Transform o models de Markov de durada variable, la metodologia d’alineament esta dissenyada per enfrontar les diferències estructurals entre partitures musicals i enregistraments d’àudio. El mètode és robust inclús en presència d’expressions musicals no anotades en la partitura, desviacions de tempo ocorregudes en les actuacions musicals i diferències de tònica i afinació. La metodologia aprofita els resultats de l’anàlisi de la partitura i l’àudio per enllaçar la informació simbòlica amb l’àudio. A més, la tècnica d’alineament s’utilitza per obtenir descripcions de l’àudio fonamentades en la partitura. L’anàlisi de l’àudio fonamentat en la partitura no només simplifica les fases d’extracció de característiques d’àudio que requeririen de mètodes de processament d’àudio sofisticats, sinó que a més millora substancialment els resultats comparat amb altres mètodes d´ultima generació que només depenen de contingut d’àudio. Les metodologies d’anàlisi presentades s’han utilitzat per analitzar el corpus CompMusic Ottoman-Turkish makam music i s’han integrat en una aplicació web destinada al descobriment musical de tradicions culturals específiques. Algunes de les metodologies ja han sigut també aplicades a altres tradicions musicals com la Hindustani, la Carnàtica i la Grega. Seguint els preceptes de la investigació oberta totes les dades creades, eines computacionals i resultats dels anàlisis estan disponibles obertament. Tant les metodologies, les eines i el corpus en si mateix proporcionen àmplies oportunitats per recerques futures en diversos camps de recerca tal i com la musicologia computacional, la extracció d’informació musical i la educació musical. Traducció d’anglès a català per Oriol Romaní Picas.

碩士
國立臺灣科技大學
資訊工程系
103
In this thesis, we propose an improved syllable pitch-contour generation method that combines ANN (artificial neural network), global variance and real-contour selection. This method not only alleviates the phenomenon of over-smoothed pitch-contour generated by ANN but also improves the naturalness level of the synthetic pitch contour. In the training stage, the automatically detected pitch contours are checked manually for some types of errors, and then corrected in terms of a program developed here. Next, each syllable pitch contour is transformed into DCT (discrete cosine transform) coefficients. Such DCT coefficients are then used to train ANN model and GV (global variance) parameters, and saved separately according to some context classification modes. In the generation stage, the ANN is used first to predict the DCT coefficients of each syllable pitch-contour according to the inputted contextual information items. Then, the generated DCT coefficients are adjusted by means of GV matching for each DCT vector dimension in order to alleviate the over-smoothing phenomenon mentioned above. Moreover, to promote the naturalness level of the synthetic pitch contours, we base on the DCT vector generated by ANN and adjusted by GV matching to select a real pitch contour from the saved contour pool corresponding to the requested context class. As for the objective assessment of our proposed method, we measure the VRs (variance ratio) under different option setting. It found that the higher VR value will be obtained if the larger weight for GV adjusting is used. In addition, the results of subjective listening tests demonstrate that an appropriate weight value for GV adjusting will improve the naturalness level of the generated pitch contour, and the processing step of real-contour selection will further improve the naturalness level.

碩士
中原大學
電機工程研究所
93
ABSTRACT The objective of this thesis is to study the pitch detection methods of speech signals. Pitch is a very important feature in voiced speech and it is widely used in speech applications. Most of the pitch detection methods are based on fixed-length frames. In 1996, Xiaohu Qian and Ramdas Kumaresan proposed a detection method which was based on variable-length frames. According to the author’s research, the proposed method can overcome some weaknesses of other methods based on fixed-length frames, and can get more accurate results. In this thesis, we study the Xiaohu Qian and Ramdas Kumaresan method and try to improve their algorithm. We also study the effects of applying single clipping techniques in the algorithm. In our simulations, we used speech samples from MAT-2000 and compare the results of different algorithms. From the simulation results, we see that the proposed method can further improve the performance.

碩士
國立高雄應用科技大學
電機工程系
99
This thesis presents the dynamic behavior simulation of fixed-speed variable-pitch wind energy conversion systems in SihMen and SihHu wind farms, operating under normal and abnormal conditions. The components of the system were developed using Simulink together with SimPowerSystems and then employed to cater for the dynamic behavior of the system, including wind turbine model, induction generator model, three-phase power transformer model, capacitor bank model, and static load model. The simulation results show that the system operated acceptably under those conditions and are coincident with practical operations. The dynamic behavior studies of fixed-speed variable-pitch wind energy conversion systems are essential for wind turbine power generation system planning,operation, and further expansion。

碩士
國立成功大學
機械工程研究所
83
In this thesis, two kinds of tool path generation methods areachining Variable Pitch Lead Screw with surface meshing elements (V.P.L.S.) on five-axisolled machine. The first method is by generating method employs the cuttere geometry of the cylin- drical roller which drives the envelope surface of V.P. L.S. .l settings is calculated and the tool path generated. A five-axis machine center is usedng of the screw profile. The second method is by combined generating and sculpturing-mill cutter. Through the coordinate transformation,the surface vector operation and theol-axis and tool offset is calculated, this new method combined surface generating withring for the V. P.L.S.surface. The mathematical error in u and v directions between the toolnufacture path has been ana -lyzed and used as a basis for the selection of tool path controlrference check for identifying overcut is also performed by comparing the radius ofe surface to the radius of the tool. Finally, the developed methods are verified with thecomputer graphics and solid cutting software. The NC program is also verified through a trial cutrial. The results showed that the mathematical errors of V.P.L.S. surface can bein tolerance by the proposed methods.

碩士
國立臺灣大學
工程科學及海洋工程學研究所
98
The thesis aims to develop a novel pitch control system of a large wind turbine driven by a variable-speed pump-controlled hydraulic servo system. In order to realize practical experiments of the pitch control, the full-scale test rig of the hydraulic pitch control system of a 2 MW wind turbine’s blade, including a novel mechanism of pitch control, a variable-speed pump-controlled hydraulic servo system, a disturbance system and a PC-Based control system, are designed and set up. The variable-speed pump-controlled hydraulic servo system, which contains an AC servo motor, a constant displacement hydraulic piston pump, two differential hydraulic cylinders and hydraulic circuits, performs high response and high energy efficiency, such that it is suitable for the applications in wind turbines. Besides, in order to implement the pitch control in the proposed novel pitch control system, the adaptive fuzzy controller with self-tuning fuzzy sliding-mode compensation (AFC-STFSMC) is developed to design the pitch controller. Finally, the developed variable-speed pump-controlled hydraulic servo system has been realized and verified for the path tracking control of the pitch control of the wind turbines by practical experiments in the full-scale test rig under different path profiles, load torques, and random wind speed. The simulation results of the hydrostatic transmission varable speed control system which is used on 2 MW wind turbines are implemented in this research. Through analyzing of the simulations, the hydrostatic transmission system can replace the gear box and has many advantages used in large wind turbines.

博士
國立成功大學
機械工程研究所
83
Based on curvature theory of differential geometry for spatial curves and surfaces, and curvature theory of conjugate surfaces, this research firstly derives the following curvature equations: principal curvatures, principal directions, normal curvatures along any tangent direction at any point of screw surfaces, induced principal curvatures, induced principal directions, induced radii of curvature, direction of contact line and the geodesic torsion along that direction, lubrication angle, and the condition for avoiding undercutting between the mated surfaces of the screw and the meshing elements. Then, analysis is carried out for various curvatures characteristic of variable pitch lead screws with cylindrical and conical meshing elements, respectively. Furthermore, based on the coordinate transformation and theory of conjugate surfaces, we derive the geometric equations of the variable pitch lead screws with hyperboloidical meshing elements. Then, principal curvatures, principal directions, and geometric characteristics of the hyperboloid of revolution are studied based on differential geometry and curvature theory of ruled surface. And, the curvature characteristic of variable pitch lead screws with hyperboloidical meshing elements are concluded. Finally, the effects on the curvatures of screws for four different motion curves and three angular parameters of the variable pitch lead screws with ruled- revolution surface are compared.

碩士
國立成功大學
機械工程研究所
83
The Variable pitch lead screw transmission mechanism is one of important units in shuttleless weaving looms. It plays a major role regarding the performance of shuttleless weaving looms. A variable pitch lead screw transmission mechanism consists of a slider-crank mechanism, a variable pitch lead screw, and four meshing elements adjacent to both the slider and the screw. The screw is driven by the power flow through the crank, the con- necting rod, the slider, and meshing elements. The purpose of this research is to study the effect of geometric parameters on the kinematic and dynamic performances of variable pitch lead screw transmission mechanisms and to obtain optimum designs. Variable pitch lead screws are generated based on specified meshing elements with special motion curves. Meshing elements of ruled-revolution-surface (cylinder, cone, and hyperboliod of one sheet) and involute-revolution-surface (concave involute- revolution-surface and convex involute- revolution-surface) are adopted. And, the corresponding motion curves are modified trapezoidal curve, modified constact velocity curve, modified sine curve, first type polynomial curve, and second type polynomical curve. A computer program is developed for analyzing kinematic and dynamic performances of designed variable pitch lead screw transmission mechanisms. Five different sets of geometric parameters are inputed into this program to obtaine kinematic and dynamic performances. The results are analyzed, and the effect of geometric parameters are sumarited. In con- clusion, this work provides a powerful tool for selecting geo- metric parameters, meshing elements, and motion curves in designing optimum kinematic and dynamic performances of variable pitch lead screw transmission mechanisms for shuttleless weaving looms.

碩士
長庚大學
機械工程學系
99
As the rise of environmental consciousness, renewable energy becomes increasingly more prevalent, and wind energy is being used extensively for generation of electricity. Small-sized horizontal-axis wind turbines (SHAWT) offer great advantages in off grid system in rural and remote areas. However, present designs of SHAWT have some defects, such as high startup speed, fixed pitch angle and additional safety device for strong wind, etc. In order to solve these problems, we build wind turbine blades with variable pitch angle mechanism that have high wind speed efficiency, stall control and low startup speed simultaneously. The purpose of this research was to examine the performance of newly developed mechanism. In theoretical analysis, we programmed algorithms based on the Blade Element Momentum (BEM) theory with C programming language to predict the blades performance. And we also development Equation for wind turbine blades with variable pitch angle mechanism, to obtain the relationship between the blades rotational speed,  and the pitch-angle variation, v. In experimental design, we establish a car-mounted experimental bench to gain performance data of the blades, which allows us to simulate variable wind conditions by controlling vehicle speed. A magnetic particle brake provides shaft load, and rotational torque sensor used for rotation speed and load measurement. An anemometer is used for wind speed measurement. All the data are recorded in a portable data logger for further analysis. The test result shows that the experimental bench is capable of measuring instantaneous wind speed, rotational speed, and shaft load of the turbine blades. Moving average method was applied to analog data for measure error reduction. The experimental data (Power-) are greatly consistent with the theoretical data, but due to the dynamic stall and the inevitable gust winds, the experiment data has circulatory phenomenon. Furthermore, current design of the safety pin and the pin hole may induce an unsteady turbine performance when Tip Speed Ratio (TSR) > 5. To solve this problem, we illustrate three feasible methods for future research.

碩士
國立虎尾科技大學
航空與電子科技研究所
100
In viewing that the Vertical Axis Wind Turbines (VAWT) have the advantages over the Horizontal Axis Wind Turbine (HAWT) in insensitive to changing wind directions, low noise and easy installation for buildings in urban and suburban areas, they are being favorably considered for current and future green living environment. On the other hand, the VAWTs are suffered from the inherent problems of no self-start, lower efficiency compared to HAWT, and structural vibration. These problems enlighten that more research efforts are needed, in order to improve the performance of the current commercial VAWT products. This study is intended to improve the performance a VAWT by controlling the pitch angles of the turbine blades while rotating. A single blade wind turbine simulation is performed firstly to investigate the unsteady aerodynamic characteristics and the relation between the tangent force corresponded to rotating angle. The NACA 0015 airfoil is chosen as the section of the rotor blade with chord length 9cm and the radius of the wind turbine is 45cm. The wind speed and tip speed ratio are 7m/s and 2.5. Several fixed and variable pitch angle models are applied to investigate the unsteady flow field of the wind turbine by the methods of computation fluid dynamics. Results show that these blade pitch control models reduced effectively the negative torque regime as well as increase the tangent force of the turbine blade about 8.18% comparing with the without pitch control model. A three blades model is proceeded to study the aerodynamic characteristics of the vertical axis wind turbine. The effects of turbine performance are carried out with varying design parameters including thickness, chord length and camber. Results show that, the average torque coefficient is increased at lower tip speed ratio for the blades of proper thickness. The camber airfoils have the potential to self-start; however, the average torque coefficient shows a reduction in peak efficiencies. The longer the chord length of the blade, the average torque coefficient is reduced. However the average torque is increased. And the point of maximum average torque occurs at lower tip speed ratio. For the pitch control consideration, the models of pitch control are related to tip speed ratio. An appropriate pitch control model can effectively decrease the range of negative torque and the vibration of the wind turbine. The average torque coefficient as well as the energy capture efficiency can be improved. Therefore, the efficiency of the wind turbines in power generation will be enhanced. The efficiency can be raised 243.16% with fixed pitch control. And the efficiency can be enhanced to 486.06% with variable pitch control.

碩士
國立成功大學
機械工程學系
86
This thesis investigate the influence of variablly spaced cutting teeth on milling and wheel grinding force. Based on the tooth sequence function which is composed of geometry of cutting edges, we combined it with elementary cutting function to get milling cutting force for a two tooth face milling cutter. For the purpose of analyzing the grinding geometry, it is convenient to liken the grinding wheel action to that of a milling cutter, with the cutting points corresponding to cutter teeth. We consider the randomness of the cutting edges on the grinding wheel face. Similarty, we model the variable distance between cutting points around the wheel periphery by using Gauss distribution. the dynamic wheel grinding force is derived with elementary cutting function by considering the characteristics of abrasive geometry and its convolution. Finally, milling and dynamic whell grinding forces models are verified with experiments and the results are discussed.

碩士
國立成功大學
機械工程研究所
83
This thesis presents an analytical methodology on the NC data eneration for automation measurement of variable pitch lead screw on coordinate measuring machine and mutli-axis machine tools.he desired probe location and the ability functions of 4-axisMM and two multiaxis machine tools are derived by a modified notation. NC data equations are obtained by solving the machine''sink variables through equations of its ability function and theesired probe location matrices.This methodlogy is a general onend is applicable for various mechanical element measuring. Itlso combines the activities of design and quality control, thusaking the production process more flexible, automatic and controllable.

碩士
國立成功大學
機械工程研究所
81
In this thesis , two kinds of tool path generation methods are developed for machining Variable Pitch Lead Screw with four cylindrical meshing elements (V.P.L.S.) on four-axis numerical control machine . The first method employs end-mill cutter , According to the geometry of V.P.L.S. mechanism , the machine tool settings is calculated and the tool path is generated , A 4-axis machine center with angle head attachment is used for the machining of the screw The second method employs ball-end mill cutter, Through the coordinate transformation , the surface normal vector operation and the tool offset calculation , this new method combined surface generating with surface sculpturing for the V.P.L.S. surface . Finally , an example for N C milling of Variable Pitch Lead Screw with four cylindrical meshing elements is presented . The results show that the mathematical errors of V.P.L.S. surface can be controlled within tolerance by the proposed methods .

博士
國立成功大學
航空太空工程學系
105
The goal of this dissertation is to construct a system that can use at outdoors and land quadrotors on a narrow (1.2 x 1.2 m) and fast moving (3 m/s) vehicle. In this dissertation, we propose solutions for two key issues related to this research 1. Positioning accuracy improvement We propose a visual positioning system to improve the accuracy of the original positioning system. Unlike most studies that place the system on an unmanned aerial vehicle (UAV), we place the system on a carrier vehicle. The advantage of this architecture is that it significantly reduces the equipment required for the unmanned aerial vehicles, thus it is suitable for UAVs of all sizes. In order to improve the success rate of recognition in cloudy or strong sunlight, we propose Adaptive Background Subtraction and Adaptive Background Threshold algorithms. The image moment of the extracted pattern is then compared to that of the target pattern to confirm the target. Then we calculate the relative position information according to the lens parameters. Benefit from the combination of GPS and inertial measurements is that the system can provide continuous position information when the visual positioning system is temporary unavailable. 2. Quadrotor robustness improvement A variable-pitch quadrotor is proposed to replace the traditional quadrotor as a carrier-based aircraft. Because of its high dynamic bandwidth and more complete control of the output, it is more suitable for operation in harsh environments. However, the variable-pitch quadrotor is completely different from the general quadrotor in the yaw equation; therefore, the traditional control allocation method cannot be applied to the variable-pitch quadrotor. In this paper, we analyze the force and moment equations under various conditions, and derive the control allocation method for the variable-pitch quadrotor. The design of the automatic landing and take-off control system is addressed in this dissertation. Various experiments are conducted to simulate the dynamic motions of the vessel, including up and down motions and moving forward motion. Finally, the quadrotor successfully lands automatically on a moving rover at the speed of 3 m/s in outdoor environment.

碩士
國立成功大學
機械工程學系碩博士班
98
The linear type blow-molding machine with a variable pitch lead screw consists of a heating system, a linear blow-station, a variable pitch lead screw transmission system, and an infeed-and-outlet system. The va-riable pitch lead screw (VPLS) transmission system consists of a slider, a fixed screw, a rotary screw, and a catch device. It transfers the bottle from the heating system to the blow-station. The design of the motion of VPLS transmission system affects the efficiency of blow-molding machine. This works presents a systematic analytical method to design the motion of VPLS transmission system to improve the performance of blow-molding machine. Firstly, the motion of the VPLS transmission system is analyzed. Based on the design requirements and constraints of the motion of trans-mission system, the curve of VPLS is synthesized by applying the cam motion curves (MT, MS, and MCV). According to Newton’s law and the definition of pressure angle, the pressure angle of the cam mechanisms and the kineotastatic analysis are evaluated. The kinematic and kinetos-tatic characteristics are improved based on the optimal theorem by using the Bezier and Fourier series curves as the design curves. As a result, the motion curve by using the optimum method approach improves the ki-nematic and kinetostatic characteristics of the transmission system of the blow-molding machine and decreases the pressure angle of the VPLS and the input force of the transmission device.

碩士
國立成功大學
機械工程研究所
82
In this thesis, two kinds of tool path generation methods are developed for machining of Variable Pitch Lead Screw with four oscillatory meshing elements (V.P.L.S.) on five-axis numerical controlled machine. The first one is by generating method with form-mill cutter, according to the geometry of V.P.L.S. mechanism. The machine tool settings is calculated and the tool path is generated. A five-axis machine center is used for the machining of the screw profile. The other method is by combined generating and sculpturing method with end-mill cutter. Through the coordinate transformation, the surface normal vector operation and the tool offset calculation, this new method combined surface generating with surface sc Finally, the developed tool path generationmethods are verified through computer graphic simulation and the trial cut with model material. The advantages of the proposed methods over the sculpturing method are discussed. The results show that the mathematical errors of V.P.L.S. surface can be controlled within tolerance by the proposed methods.

碩士
國立臺灣大學
工程科學及海洋工程學研究所
103
Most of the small wind turbines are designed with no control or passive control due to the cost consideration so that the electric generation performance is limited as the wind speed is over the rated wind speed. Thus, the objective of the paper is to improve the electric generation performance by developing a novel active pitch control system and a rotor constant rotational speed control for a 2kW small wind turbine. The study first developed a novel mechanism design for the active-controlled pitch control system. The novel mechanism is the DC servo motor-driving variable-pitch bevel mechanism. By using the PID controller, the one to three bevel gear chain driven by DC servo motor is applied to adjust the pitch angles of the three blades at the same time. Then, the dynamic simulation of the overall system of wind turbine was developed by combining softwares of FAST, ADAMS and MATLAB. After that, the proposed novel mechanism design of the active pitch control and the constant rotational speed control of rotor could be verified via dynamic simulation. For that, the controllers of pitch control and the constant rotor constant rotational speed control were developed by PID control and fuzzy sliding mode control. The experimental prototype system was modified according to the TECO 2kW small wind turbine which original type has no control. The novel mechanism for the active pitch control system and the required controller system were integrated and tested in the open wind tunnel. When the wind speed is above the rated wind speed, the DC servo motor-driving variable-pitch control system starts to work to regulate the pitch angle to keep the constant rotational speed of rotor. The one to three bevel gear chain driven by DC servo motor is applied to adjust the pitch angles of the three blades at the same time. Through the active pitch control system, the constant rotational speed control of rotor can be implemented.

碩士
國立屏東教育大學
體育學系碩士班
102
This research was according to the extension of schema theories, which based on variability of practice hypothesis. It compared with the constant practice, applying to sports schema of Tee-ball pitch and learning of the pitch skills. It also discussed the influence which were about different practices of tee ball accuracy pitch of primary school students. It adopted the involved model in this research. The fifth grade students of Yili primary school, Pingtung County, took part in this experiment. It divided 60 official participants into different layer clusters, whose ages were 11.38±0.21 years old, the heights were 142.02±5.57 cm, the weights were 41.93±6.03 kg. It represented the analysis of quantity. Before tests, the researcher conducted a 40 minutes class about the accuracy pitch of Tee-ball. Then gave a 7m pre-test to the participants. And according to the results of the pre-test, divided the 60 participants into 5 groups which were the variable practice group, 5m constant group, 6m constant group, 8m constant group and 9m constant group. 4 weeks later, when the researcher gave post-test, retention test and transfer test to the participants, the constant groups pitched 12 times in a fixed distance while the variable groups pitched in the distance of 5m, 6m, 8m and 9m. The participants pitched 3 times in each distance, 12 tims altogether, paused 5 seconds between each pitch. The independent variabilities in this research were based on different groups and tests. The accuracy pitch skills were the dependent variabilities tested in the Mixed design Two-way ANOVA to certify the differences. If the interaction in this way was significant, it would take the simple main-effect tests. The statistic significant level was α＝0.5. After discussing the results of the examining , the following were conclusions: A. Represented skill analyse : It had no difference of represented skill in different groups (variable and constant practice) and tests (pre-test and post-test). It had differences in pre-test and post-test. Results of post-test were better than pre-test means that after 4 weeks long practice, accuracy pitch skills were improved. There was a interaction between different groups and tests. The represented skill performances of post-tests both in variable and constant groups were superior than those of pre-tests. It meant that learning effects of the skill acquisition phase were equal in the variable and constant groups. B. Maintained skill analyse: Maintained skill performances did not differ in different groups and tests (pre-test, post-test, retention test). There were significant differences between the pre-test , the post-test and the retention test. Results of post-test and retention test were obviously superior than those of pre-test. Results from high to low were those of post-test, retention test and pre-test. An Interaction existed in maintained skill performances of different groups and tests. Retention test of maintained skill performance in variable group was better than in 9m constant group. After giving each kind of constant groups, results of post-test were better than those of retention test. In 5m and 6m constant groups, results of retention test were better than those of post-test. In variable groups, results of retention test were superior than those of pre-test and post-test. C. Transfer skill analysis: There was no significant difference of transfer skill performances in different groups and different tests (pre-test, post-test, transfer test 1, transfer test 2). significant differences existed in pre-test, post-test, transfer test 1 and transfer test 2 of different tests. Results of post-test were better than those of pre-test and 10m transfer test 2. Results of 4m transfer test 1 were better than those of pre-test, post-test and 10m transfer test 2. Results from high to low were 4m beyond transfer test 1, 7m within post-test and 10m beyond transfer test 2. There was an interaction effect of transfer skill performances between different groups and different tests. For skill performances, those of 4m transfer test 1 of each variable group and constant group were all better than those of pre-test, post-test and 10m transfer test 2. Post-tests of 5m and 6m costant groups were both better than 10m transfer test 2. 10 transfer test 2 of variable group was also better than pre-test.

Στο πρώτο κεφάλαιο αναφέρονται χαρακτηριστικά της αιολικής ενέργειας. Μελετάται η ισχύς του ανέμου όπου βλέπουμε στοιχεία όπως τον τρόπο που σχηματίζονται οι άνεμοι, και περιγράφονται τα στοιχεία τη ανεμογεννήτριας και τα χαρακτηριστικά της αιολικής απόδοσης. Παρουσιάζονται τέλος, συνοπτικά, μερικά εισαγωγικά στοιχεία για τις κατανεμημένες παραγωγές, για τις κατανεμημένες πηγές ενέργειας και τον τρόπο που διανέμεται η παραγωγή της ενέργειας. Στο δεύτερο κεφάλαιο της διπλωματικής εργασίας γίνεται περιγραφή των φορτίων που υπάρχουν στα ηλεκτρικά κινητήρια συστήματα. Μελετάμε τη δομή αυτών και τα κατηγοριοποιούμε με κριτήριο τη ροπή τους. Στο τρίτο κεφάλαιο μελετάμε το τριφασικό βραχυκύκλωμα και τον τριφασικό διακόπτη. Αναφέρουμε τις παραμέτρους που παίζουν ρόλο στο βραχυκύκλωμα, τον τρόπο που συμπεριφέρεται μία μηχανή σε αυτό και τις συνιστώσες συνεχούς μεταβαλλόμενου ρεύματος. Στο τέταρτο κεφάλαιο περιγράφουμε τον τριφασικό μετασχηματιστή. Μελετάμε τις συνθήκες σύνδεσης αυτών και τον τρόπο που συνδέονται. Στο πέμπτο κεφάλαιο μελετάμε τις ανεμογεννήτριες μεταβλητής ταχύτητας, τον έλεγχο που γίνεται στον ανεμοκινητήρα για την ισχύ , τα κατάλληλα ηλεκτρονικά που χρησιμοποιούμε στις ανεμογεννήτριες, τους μετατροπείς συχνότητας και τα είδη γεννητριών. Αναφέρονται οι συνδεσμολογίες τους και ο τρόπος που ελέγχουμε τάσεις, ενεργό και άεργο ισχύ μέσω συστημάτων αυτομάτου ελέγχου. Στο έκτο κεφάλαιο γίνεται ανάλυση του αιολικού συστήματος μεταβλητών στροφών , όπου βλέπουμε τον μετασχηματισμό Park για τη μετατροπή συστήματος αξόνων, αναλύουμε το μοντέλο της μηχανής σε άλλο πλαίσιο αναφοράς (d – q) και εφαρμόζουμε διανυσματικό έλεγχο. Στο έβδομο κεφάλαιο σχεδιάζουμε το σύστημα που μελετάμε με το πρόγραμμα MATLAB / Simulink, Γίνεται μία αναφορά στους ελέγχους που μελετήθηκαν στο πέμπτο κεφάλαιο, χρησιμοποιώντας τους για την εξομοίωση. Αναλύουμε τον τρόπο που αρχικοποιούμε το σύστημά μας και εξομοιώνουμε το σύστημα με τις ανεμογεννήτριες παραθέτοντας τις απαραίτητες κυματομορφές.
The first chapter indicates characteristics of wind energy. Studied the wind power, where we see how winds are formed, and we describe the elements of wind and the characteristics of wind performance. Presented finally, briefly, a few introductory information on distributed generation for distributed energy sources. In the second chapter, there is a description of the electric motor systems loads. We study their structure and categorize them according to their torque. In the third chapter we study the three-phase fault and three phase switch. We report the parameters that play a role in short and how it behaves a machine on it. The fourth chapter describes the three-phase transformer. We study the association of these conditions and it is connected. In the fifth chapter we study the variable wind speed control, in Wind Turbines, the power, electronics that we use, frequency inverters and types of generators. We specify the connections and the way we control voltages, active and reactive power through control systems. The sixth chapter is an analysis of the variable wind speed system, where we see Park transformation to convert the axis system, we analyze the model of the machine in another frame of reference (d - q) and apply vector control. In the seventh chapter we design the system with the program MATLAB / Simulink, simulating the system. We analyze the way that we do the initialization of our system in order to simulate in several wind speeds, giving the necessary waveforms.

Η παρούσα διπλωματική εργασία πραγματεύεται την μελέτη και ανάλυση ενός αιολικού συστήματος με ασύγχρονη μηχανή διπλής τροφοδοσίας. Αρχικά, γίνεται μία εισαγωγή στις ανανεώσιμες πηγές ενέργειας, με ιδιαίτερη αναφορά στην αιολική ενέργεια. Κατόπιν, περιγράφονται τα κυριότερα ανεμολογικά χαρακτηριστικά οι διάφοροι τρόποι ταξινόμησης των ανεμογεννητριών που υπάρχουν σήμερα, τα δομικά στοιχεία αυτών, καθώς και οι βασικές τεχνικές ελέγχου που εφαρμόζονται σ’ αυτές. Ακολουθεί η γενική παρουσίαση μίας διπλά τροφοδοτούμενης επαγωγικής γεννήτριας. Προκειμένου να γίνει μελέτη των μεταβατικών καταστάσεων, παρουσιάζεται το δυναμικό μοντέλο και ο διανυσματικός έλεγχος μίας διπλά τροφοδοτούμενης επαγωγικής γεννήτριας διπλής τροφοδοσίας. Τέλος, γίνεται η προσομοίωση ενός αιολικού πάρκου, που περιλαμβάνει ανεμογεννήτριες αυτού του τύπου και μελετώνται τα δεδομένα που προκύπτουν για τυχαίες μεταβολές του ανέμου.
The subject of this thesis is the study and analysis of a variable speed wind turbine equipped with a doubly-fed induction generator (DFIG). At first, an introduction is made of the renewable energy sources, with special mention of the wind energy. Then, there is the description of the different types of wind turbines than exist nowadays, their components and their aerodynamic conversion. A general presentation of a doubly-fed induction generator (DFIG) is made. After that, the dynamic model and the vector control doubly-fed induction generator are presented in order to study various transition phenomena. Finally, the simulation of a wind farm that includes wind turbines of this type, is made and we study the effects of sudden changes of the wind speed.