Made available in DSpace on 2014-10-09T12:54:14Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:14Z (GMT). No. of bitstreams: 1 12437.pdf: 4743815 bytes, checksum: 224eec9c107091a47a85eb64ff2540c5 (MD5) / Dissertacao (Mestrado) / IPEN/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

Abstract The aim of this research work is to develop a tool for condition monitoring of squirrel-cage motors using axial magnetic flux measurements, and to design a diagnostics system for electrical motors. The basic theory of the measurements and systems was found through literature reviews and was further developed from the experimental results of this research work. Fluxgate magnetometers and Hall effect sensors are not reliable enough for condition monitoring purposes, but measurements by flux coil sensors can reach adequate reliability. The useful frequency area of the flux coil sensor is from about 0.2 Hz to 15 kHz, an area is well applicable for condition monitoring of squirrel-cage motors. Output voltage is frequency dependent, increasing towards higher frequencies. Sufficient sensitivity is usually reached by a flux coil sensor having a diameter of about 30 cm and the number of turns of about 200. Sensitivity can be improved by increasing the diameter or number of turns of the coil. The sensor should be placed axially centred on the end of the motor, and measurements should be made with the loaded motor in steady operation. Output voltage is typically from the microvolt to millivolt level, however, installation inside the motor can increase it from tens of millivolts to some volts. The dynamic resolution requirement of measurement is about 70 dB and the highest line resolution needed for the spectrum analysis is about 3200 lines. Time base signal can be used to study rapid disturbances of flux caused by mechanical loading or switching of the frequency converter. Various motor failures cause specific variation to the frequency distribution of flux, so spectrum analysis is well applicable for condition monitoring. Reference measurement of each motor is required because stator winding factors, installation tolerances, operating conditions and mechanical load affect leakage flux. A broken rotor bar failure can be detected from the amplitude difference between the supply frequency and its rotor bar induced sideband. A broken rotor end ring failure can be detected by the amplitude difference between the slip frequency and the supply frequency. However, it was found that the stator current spectrum is a more reliable method of detecting both these rotor failures. The supply voltage asymmetry can also be evaluated by specific sidebands of axial flux. Turn to turn failure of the stator winding was most reliably detected by sidebands around the rotor slot pass frequencies. Equations for frequency converter supplied motors are the bases for similar equations, but the supply frequency is replaced by the output current frequency of the converter. The developed diagnostics system design for condition monitoring of ac motors includes stator current, flux coil, temperature, vibration, partial discharge, bearing current and voltage measurements. At the system diagnosis stage these measurable signals are divided to time base and frequency base signals and for each of them a fault indicator is determined. For flux coil measurements four fault indicators were found: rotor bar failure ratio, rotor end ring failure ratio, stator winding turn to turn ratio and supply voltage asymmetry operation ratio. With these failure indicators we determine failure location, state and cause. From this information a lifetime prediction of the motor is made. The results of this work are used to analyse flux coil measurements of squirrel-cage motors. In addition the research has led to a special application to monitor electric motors using an on-line condition monitoring system for paper machines and power plants.

M.Ing. / Shaft encoders, are devices generally used in speed and position control applications for sensing position of rotational and linearly moving objects. Most conventional shaft encoders operate on the principle of reading encoded information off a disk, which is fitted to the shaft or using resolver units. Problems are often experienced in fitting high-resolution encoder disks or resolvers to small motors or moving objects. The resolution of an encoder system, using an encoded disk, is a function of the maximum number of slots that are cut in the disk. If the disk itself has to be very small, physical constraints limit the accuracy of the encoder. However, any machined surface will have characteristic marks on it and it is believed that these marks can be used to obtain a unique analogue signature for the shaft. This analogue signature can then be used to gain further knowledge about the rotational speed and possibly the position of the shaft. This project was an investigation into the possibility of gaining accurate, absolute positional information for a rotating shaft. An optical source- and detector system is used in the process of observing the irregularities on the shaft surface. This signal data is gathered and processed using a technique, which compensates for variation in shaft speed during the period in which data is sampled. The entire algorithm, which calculates the absolute position of the shaft from the data gathered, was implemented on a digital signal processor board. Results were evaluated and the maximum non-linearity of the test system was found to vary between 1.8% and 3.7% of full-scale deflection. The resolution of the sensor was between 1.5 and 2.5 degrees with hysteresis between 1% and 1.5% of full scale deflection. The test system allows for rotation in any direction. Possible problems that might be encountered with this type of encoder system are pointed out in this report. Future developments and possible improvements are also discussed.

The microtubule cytoskeleton plays a vital role in the spatial-temporal organization of subcellular cargo required to maintain homeostasis and direct cell division. Cytoplasmic dynein and kinesin are opposite-polarity, microtubule-based motors that transport a wide variety of cargo throughout eukaryotic cells. While much is known about the stepping mechanism of kinesin from decades of study, cytoplasmic dynein's size and complexity has limited our understanding of its underlying motor mechanism. Here, a minimal, artificially-dimerized dynein motor was observed with two-color, near-simultaneous, high-precision, single-molecule imaging, which reveals the stepping pattern of each motor domain as dynein moves along the microtubule. Although the stepping behavior appeared highly irregular and erratic, with large variability in step sizes, side stepping behavior, and back stepping behavior, dynein did show evidence of tension-based, coordinated stepping. Furthermore, advances in DNA nanotechnology enabled us to engineer a synthetic motor-cargo system, referred to as a chassis, to investigate how multiple cytoskeletal motors work in teams to produce the myriad of motile behaviors observed in vivo. Specifically, the mechanisms that coordinate motor ensemble behavior was examined using three-dimensional DNA origami to which varying numbers of DNA oligonucleotide-linked motors could be attached, allowing control of motor type, number, spacing, and orientation in vitro. Ensembles of 1-7 identical-polarity motors displayed minimal interference with respect to directional velocity, while ensembles of opposite-polarity motors engaged in a tug-of-war resolvable by disengaging one motor species. This experimental system allowed us to test directly the tug-of-war proposed to occur during dynein's delivery to the microtubule plus-end by the kinesin Kip2. This work led to the mechanistic understanding that Lis1/Pac1, CLIP170/Bik1, and EB1/Bim1 proteins function to enhance kinesin's processivity, allowing it to win a tug-of-war and transport dynein toward the microtubule plus-end. Overall, this work elucidated mechanisms of ensemble motor function and dynein's stepping mechanism in addition to building significant tools to further pave the way for future studies to elucidate how cytoskeletal motors function to organize cellular cargos.

The modelling and control method of a vehicle climatronic system, based on MATLAB/SIMULINK, is presented. In order to achieve high modelling accuracy, a developed simulation model library is introduced. The modelling approach is described and the developed models are validated with some of experimental data obtained. The models are nonlinear, independent of fluid type and based on thermo-dynamic principles. Analysis of the cooling circuit modelling and empirical real-time control models are created by using Fuzzy logic controller and Stateflow. Both of control input and output are implemented essentially at original vehicle CAN-Bus system. Feasible digital automatic control strategy basic to fuzzy theory, hardware and software solution are given. The simulation experiment is achieved with the Hardware-in-Loop technology. This control methodology is easily operated and worth applying for any further studies or methods.

If the rotor of an induction motor is not concentric with the stator then an electromagnetic force is generated in a direction that will increase the eccentricity. This is called unbalanced magnetic pull (UMP). The first part of the work presented in this dissertation develops theoretical models which allow the calculation of the UMP in cage induction motors due to static rotor eccentricity. These account for any winding configuration including parallel stator winding connection. The second part of the work verifies the models experimentally using two different cage induction motors. The agreement between predicted and measured values of UMP and line current is found to be good. The investigation leads to several new aspects of the damping effects of parallel stator windings and the cage rotor being highlighted.

No description available.

Orientador: Ely Carneiro de Paiva / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T21:55:57Z (GMT). No. of bitstreams: 1 MartinezArias_RonaldRicardo_M.pdf: 6818308 bytes, checksum: d91e74cb8827b9ee03bcb0e84ccc9bd0 (MD5) Previous issue date: 2014 / Resumo: No presente trabalho, o modelo dinâmico do dirigível do Projeto AURORA (Gomes e Ramos, 1998), (Azinheira et al., 2001) e (Azinheira et al., 2008) é adaptado para considerar 4 motores ao invés de 2 apenas. Além disso, esses motores possuem acionamento elétrico (DC-Brushless) ao invés de propulsão por motor de combustão. Esses motores poderão trabalhar em acionamento diferencial, ou seja, motores frente-trás ou esquerda-direita com forças de propulsão diferentes, com a finalidade de gerar momentos e forças que complementem os demais atuadores do dirigível, como as superfícies de cauda ou leme. Duas inovações principais caracterizam esse novo sistema. O primeiro ponto é a utilização de quatro propulsores vetorizáveis ao invés de apenas dois como o usual. O segundo ponto é a angulação de 20 [graus] presente na fixação dos propulsores. Essa angulação faz com que, ao ser vetorizado para cima, cada propulsor gere uma componente de força lateral, além das componentes longitudinal e vertical. Se a intensidade da força gerada em cada propulsor for a mesma, obviamente as forças laterais geradas num par de propulsores se cancelam, e temos uma situação parecida com a atuação clássica de dirigíveis, gerando forças apenas para frente e para cima. Mas se, por outro lado, as intensidades de força nos propulsores de um dado par (dianteiro ou traseiro) forem diferentes, então forças resultantes laterais (bem como momentos) podem ser obtidos no CV (Centro de Volume) do dirigível. Assim, se o par de propulsores dianteiros gera uma componente lateral de forças para a direita, por exemplo, e o par traseiro gera uma componente lateral para a esquerda, então temos a geração de um momento de guinada positivo (horário), supondo obviamente que os motores encontram-se vetorizados. Essa é a chamada propulsão diferencial esquerda-direita que permite a geração de momentos de guinada em baixas velocidades, de tal forma compensar a baixa eficiência aerodinâmica da cauda com pouca incidência de ar (vento relativo). Outra possibilidade é a geração da propulsão diferencial dianteira-traseira, onde ambos propulsores dianteiros fornecem força de igual intensidade, mas de amplitude diferente daquela gerada pelos propulsores traseiros. As forças laterais são canceladas, mas um novo momento de arfagem pode ser gerado, e com um grau de liberdade a mais do que na situação onde se usava apenas dois propulsores vetorizáveis. Podemos obter inclusive um momento de arfagem no dirigível e ainda mantê-lo na posição "nivelada" de ângulo de arfagem (pitch) nulo. O uso da propulsão diferencial dianteira-traseira permite também obter uma mudança contínua e suave nas forças e momentos ao se variar a velocidade de operação do dirigível (airspeed). Evita-se assim a transição brusca de atuação que é observada quando o dirigível, na configuração clássica de apenas dois motores, passa das baixas velocidades (usando vetorização) para as altas velocidades (dispensando vetorização). Dessa forma, tanto a propulsão diferencial lateral (esquerda-direita), como a longitudinal (traseira-dianteira) obtida com essa configuração inédita, permite gerar momentos e forças que complementam os demais atuadores do dirigível, como as superfícies de cauda ou leme. Ressalta-se que as diferentes configurações de propulsão motora como essa proposta aqui considerada (de domínio do Projeto DRONI) poderão aumentar a eficiência e desempenho das abordagens de controle linear e não linear já desenvolvidas previamente no âmbito do Projeto AURORA / Abstract: In this paper masters, the dynamic model of AURORA Project airship (Gomes e Ramos, 1998), (Azinheira et al., 2001) and (Azinheira et al., 2008) is adapted to consider 4 engines instead of 2. Furthermore, those engines as electric start (DC-Brushless) instead of propulsion combustion engine. Engines can work with differential start, that is, front-back or left-right engines with different thrust forces. It has the purpose of generating forces and torques which complement other airship actuators, such as the tail and rudder surfaces. Two main innovations characterize this new system. First, it uses four thrusters with thrust vector control instead of just two as usual. Second, it is the 20 [degrees] angulation that is present in the thrusters setting. This angulation allows each thruster generates a lateral force component besides the longitudinal and vertical components when thrusters are vectorized upward. If the amount of force generated in each thruster is the same, obviously, the addition of lateral forces generated in a pair of thrusters will be zero, and we will have a similar situation with the classic airship performance, generating forces only forward and up. But if the amount of force on thrusters on a given pair (front or back) are different, then resulting lateral force (and torques) can be obtained on airship CV (Volume Center). Thus, if the front pair of thrusters generates a lateral force component to the right, for example, and the rear pair generates a lateral component to the left, we have a generation of yaw torque positive (clockwise), obviously assuming that the engines are vectorized. This is called the differential thrust left-right which allows the generation of yaw torques on low speeds, in order to compensate a low aerodynamic efficiency of tail with little air effect (relative wind). Another possibility is the generation of the differential thrust front-back, where both front thrusters provide equal amount of force, but with a different amplitude than the force generated by the rear thrusters. The lateral forces are canceled, but a new pitch torque can be generated, and with a degree of freedom more than in the situation where it was used only two thrusters with thrust vector control. We can get even a pitch torque on the airship and still keeping it on null pitch angle position. The use of diferential thrust front-back allows also getting a slight and continuous change on the forces and torques when is varied the airship operation speed (airspeed). It avoids the abrupt transition of performance that is observed when the airship, on classic configuration of only two engines, goes through from low speeds (using vectoring) to high speeds (dispensing vectorization). Thus, both the differential thrust lateral (left-right) as the longitudinal (front-back) obtained with this configuration unprecedented, it allows to generate torques and forces that complementing the other airship actuators, such as tail surfaces or rudder. It should be noted that different confiurations of thrust (Project DRONI) may increase the efficiency and performance of linear control approaches and nonlinear previously carried out under the AURORA Project / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Biomolecular motor based transport reconstituted in synthetic environment has been recently established as a promising component for the development of nanoscale devices. A minimal system consisting of microtubules propelled over a surface of immobilized kinesin motor proteins has been used to transport and manipulate cargo for molecular sorting, analyte detection, and other novel nanotechnological applications. Despite these achievements, further progress of the field and translation of the reported applications to a real-world setting require overcoming several key challenges, such as, development of effective cargo conjugation strategies and precise control of the transport directionality with the reconstituted biomolecular motor systems. The challenge of cargo conjugation is addressed in this thesis through the development of a robust bioorthogonal strategy to functionalize microtubules. The versatility of the developed method is demonstrated by covalently conjugating various types of cargos to microtubules. Further, the effect of the linker length on cargo attachment to microtubules is investigated by attaching cargo to microtubules via linkers of different lengths. By using kinesin-driven transport of microtubules that are covalently conjugated to antibodies, detection of various clinically relevant analytes is demonstrated as proof-of-principle applications for biosensing. Finally, the challenge of gaining control over transport directionality is addressed through topographical guiding of microtubules in nanostructures, and optimization of assay parameters to achieve successful guiding of microtubules. Spatio-temporal analyte concentration, using transport in these nanostructues, is also explored to make the biomolecular-motor based applications more suitable for use real-world point-of-care setting. Taken together, the experimental work in this thesis contributes to the field of nanotechnological applications of biomolecular motors. The developed microtubule functionalization method and understanding of the effect of cargo attachment via linkers provide useful design principles for efficient cargo loading to microtubules. Moreover, establishment of assay components for successful guiding of microtubules in nanostructures is a vital step forward for practical translation of future nanoscale devices.

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