Rotundus AB är ett världsledande företag inom området för sfäriska robotar som håller på att utveckla den markbundna farkosten GroundBot(tm). För att detektera robotens translations- och rotationsrörelser används accelerometrar och hastighetsgyron. Dessutom används sensorerna för tröghetsnavigering när GPS-täckning saknas. Målet med projektet innebär att ta fram en metod för att utvärdera precisionen hos sensorer för robotens tröghetsnavigeringsenhet. Metoden koncentrerar sig på fyra av sensorernas felkällor: Skalfaktor, bias, slumpvandring och biasinstabilitet. För att beräkna skalfaktorn och biasen används linjära minsta kvadratmetoden där utsignalen från sensorn anpassas mot ett teoretiskt värde. Slumpvandringen och biasinstabiliteten utvärderas med Allans varians.

In machining centers, with the increasing trends in high precision machining, chatter has become an important problem which results in poor surface finish and low material removal rate. Chatter can be avoided with stability diagrams which provide the stable regions in the machining process for the depth of cut and spindle speed combinations. In order to obtain stability diagrams, tool point frequency response function (FRF) of the system should be obtained. Throughout this study, contact parameters which are the most critical part of the analytical modeling of spindle-holder-tool assembly in order to obtain tool point FRF, are examined. For the accurate identification of the contact parameters, a recently suggested closed form approach based on measured FRFs is improved and applied to real structures by solving several application problems. In addition to the identification of contact parameters from experimental results, in order to eliminate the dependency on experiments, artificial neural networks are used to predict contact parameters for cases for which no experiments were carried out. By using trained neural network, contact parameters are predicted for the first seen combination of tool gauge length and diameter with a high accuracy. Such an application will have an important contribution to the machining stability studies since elimination of dependency on experiments will make it possible to predict stability diagrams for different combinations of spindle, holder and tool without performing any experiments. Additionally, since accurate identification of contact parameters, thus tool point FRFs and stability diagrams are highly dependent on accuracy of the performed experiments, possible errors due the mass of the accelerometers are also investigated. In order to compensate the mass effect of the accelerometers, a structural modification with matrix inversion method is applied to the accelerometer based results.

Micromachining technologies enabled the use of miniaturized transducers in many high technology sensing systems. These transducers have many advantages like small-size, low-cost and high-reliability. One of the applications micro-machined transducers are used is inertial navigation systems, where the exact position of a moving frame is continuously monitored by tracking the linear and angular motions of the frame. Other than navigation applications, inertial sensors are used in health and military applications as well as consumer electronics. Today accelerometers capable of measuring accelerations from 0.5g-1g range up to several thousand g&rsquo / s are commercially available in the market which have been fabricated using micromachining technologies. The aim of this research is to develop such a state-of-the-art micro-machined accelerometer system, whose performance is expected to reach tactical-grade level. In order to achieve these performance values a MATLAB algorithm is developed to optimize the accelerometer performances in the desired levels. Expected performance parameters of the designed accelerometer structures are extracted from the simulations done by both Coventorware finite element modeling tool and MATLAB. Designed structures are then fabricated with silicon-on-glass, dissolved wafer and dissolved epitaxial wafer processes. These fabrication results are compared and it is observed that highest yield accelerometers are fabricated with the SOG process. But these accelerometers could not be able to satisfy tactical grade performance parameters. Best performances are obtained with DWP, but due to high internal stress, yield of the sensors were very low. DEWP increased the yield of this process from 2-3% to 45-50% but the expected operation range of the designs dropped to &plusmn / 12.5g range. Using the fabricated accelerometers in DEWP a three axial accelerometer package is prepared and tests results proved that this three axial accelerometer system was satisfying the tactical grade requirements. In addition to these a three axial monolithic accelerometer fabrication technique is proposed and sensors are designed which are suitable for this process. Best performances achieved with single axis accelerometers were 153&micro / g/&radic / Hz noise floor, 50&micro / g bias drift, 0.38% non-linearity and a maximum operation range of 33.5g which has the higher dynamic range among its counterparts in the literature. Performance results achieved with the three axes accelerometer were ~150&micro / g bias drift, &lt / 200&micro / g/&radic / Hz noise density, ~0.4% non-linearity with higher than &plusmn / 10g operation range.

MEMS accelerometers are quickly approaching navigation grade performance and navigation market for MEMS accelerometer systems are expected to grow in the recent years. Compared to conventional accelerometers, these micromachined sensors are smaller and more durable but are generally worse in terms of noise and dynamic range performance. Since MEMS accelerometers are already dominant in the tactical and consumer electronics market, as they are in all modern smart phones today, there is significant demand for MEMS accelerometers that can reach navigation grade performance without significantly altering the developed process technologies. This research aims to improve the performance of previously fabricated and well-known MEMS capacitive closed loop &Sigma / &Delta / accelerometer systems to navigation grade performance levels. This goal will be achieved by reducing accelerometer noise level through significant changes in the system architecture and implementation of a new electronic interface readout ASIC. A flexible fourth order &Sigma / &Delta / modulator was chosen as the implementation of the electro-mechanical closed loop system, and the burden of noise shaping in the modulator was shifted from the mechanical sensor to the programmable electronic readout. A novel operational transconductance amplifier (OTA) was also designed for circuit implementation of the electronic interface readout. Design and fabrication of the readout was done in a standard 0.35 &micro / m CMOS technology. With the newly designed and fabricated readout, single-axis accelerometers were implemented and tested for performance levels in 1g range. The implemented system achieves 5.95 &micro / g/sqrt Hz, 6.4 &micro / g bias drift, 131.7 dB dynamic range and up to 37.2 g full scale range with previously fabricated dissolved epitaxial wafer process (DEWP) accelerometers in METU MEMS facilities. Compared to a previous implementation with the same accelerometer element reporting 153 &micro / g/sqrtHz, 50 &micro / g bias drift, 106.8 dB dynamic range and 33.5 g full scale range / this research reports a 25 fold improvement in noise, 24 dB improvement in dynamic range and removal of the deadzone region.

The Electrical Submersible Pump (ESP) manufactured by Baker Hughes, model no. WJE-1000 is designed for wells that are expected to have a high content of abrasive solids. It is a mixed flow, tandem compression type pump. Although the erosion of the pump diffuser and impeller stages are significant, the ESP study shows that the most sever failure is due to components that affect the pump’s rotor dynamics such as radial bearings and impeller seals when eroded with 100 mesh sand. Erosion of these seals will result in an internal leakage that can significantly affect stage pressure rise, efficiency, power consumption, vibration, pump life and running cost. The erosion study utilizing 100 mesh fracture sand at 0.2% concentration, with the pump operating at 3600 RPM, 40 PSI intake pressure, 1150 GPM for over 117 hours comparisons are made to the pump’s baseline performance. Measurements of the rotor bearings, impeller seals and their corresponding stators showed that the wear patterns generally increase with time and differ by location. Stage 1 bearings and seals suffered the least amount of erosion and stage 3 rotor components suffered the most erosion. The maximum change in stage 3 bearing clearances was 223% and the maximum change in stage 3 impeller seal clearances was 300%. Performance wise the total pump efficiency dropped by 6.77%, the total pressure rise dropped by 6.3%, the pump’s best efficiency point decreased by 0.78%, and the power consumption increased by 0.49%. Pump vibration patterns also changed with time and by location. The maximum shaft orbit diameter was at stage 3 and it grew 643% in diameter after 117 hours of erosion. The waterfall plots of the pump’s ramp up changed significantly with time. After 117 hours at 3600 RPM, sub-synchronous oscillations at 67% of the synchronous speed dominated the amplitude peaks showing that the rotor vibration locked with the rotor’s first natural frequency at around 2500 RPM. After 117 hours, another sub-synchronous started showing a peak at the rotor’s second natural frequency at 1500 RPM.

This thesis reports the development of micromachined accelerometers and gyroscopes that can be used for micromachined inertial measurement units (IMUs). Micromachined IMUs started to appear in the market in the past decade as low cost, moderate performance alternative in many inertial applications including military, industrial, medical, and consumer applications. In the framework of this thesis, a number of accelerometers and gyroscopes have been developed in three different fabrication processes, and the operation of these fabricated devices is verified with extensive tests. In addition, the fabricated accelerometers were combined with external readout electronics to obtain hybrid accelerometer systems, which were tested in industrial test facilities. The accelerometers and gyroscopes are designed and optimized using the MATLAB analytical simulator and COVENTORWARE finite element simulation tool. First set of devices is fabricated using a commercial foundry process called SOIMUMPs, while the second set of devices is fabricated using the electroplating processes developed at METU-MET facilities. The third set of devices is designed for a new advanced process based on DRIE, which is under development. Mechanical and electrical test results of the fabricated accelerometers and gyroscopes are in close agreement with the designed values. The testing of the SOI and nickel accelerometers is also performed in industrial test environments. In order to perform these tests, accelerometers are hybrid connected to commercially available capacitive readout circuits. These accelerometer systems require only two DC supply voltages for operation and provide an analog output voltage related to the input acceleration. The industrial tests show that the SOI accelerometer system yields a 799 &micro / g/&amp / #8730 / Hz average noise floor, a 1.8 mg/&amp / #8730 / Hz peak noise floor, a 22.2 mV/g sensitivity, and a 0.1 % nonlinearity, while the nickel accelerometer system yields a 228 &micro / g/&amp / #8730 / Hz average noise floor, a 375 &micro / g/&amp / #8730 / Hz peak noise floor, a 1.02 V/g sensitivity, and a 0.23 % nonlinearity. Long-term drift components of the accelerometers are determined to be smaller than 20 mg. These systems are the highest performance micromachined accelerometer systems developed in Turkey, and they can be used in implementation of a national inertial measurement unit.

A avaliação da atividade física com o uso do acelerômetro é um método quantitativo, não invasivo, sendo mais preciso que métodos subjetivos, como questionários com proprietários, que podem muitas vezes induzir a erros. Seu uso pode ser relevante na rotina clínica para avaliações de terapias medicamentosas e cirúrgicas além de comportamentais. O presente estudo teve como objetivo quantificar a atividade física de cães da raça Border Collie que vivem em diferentes ambientes, como apartamento (grupo I), casa (grupo II), campo (grupo III) e centro de treinamento (grupo IV). Foram coletados os dados de 54 animais, sendo oito de apartamento, 18 de casa, 11 de campo e 17 em centro de treinamento de pastoreio, durante 72h com o uso do acelerômetro. O tempo de atividade sedentária foi maior em cães do grupo I em relação aos do grupo II e aos do grupo III. Já os cães do grupo IV tiveram maior tempo em atividade sedentária em relação aos do grupo III. O tempo de atividade leve a moderada foi maior no grupo III comparado ao grupo I e ao grupo IV, enquanto que o tempo de atividade vigorosa em minutos foi maior entre os cães do grupo II em relação ao grupo I. O tempo em atividade leve a moderada e vigorosa somados do grupo I foi menor que dos grupos II e III, enquanto o tempo do grupo III foi maior que do grupo IV. Contagem dos áxis integrados por minuto do grupo I foi menor tanto em relação do grupo II quanto III. Sendo assim, cães tem sua atividade física alterada conforme o ambiente e com exceção da atividade leve a moderada, animais de apartamento tem menos atividade física do que os de casa. Cães de casa e campo não tiveram nenhuma diferença de atividade física, bem como cães de apartamento e centro de treinamento nos parâmetros analisados. / The use of subjective methods to evaluate levels of physical activity, as owner questionnaires, may led to misguided information. The use of the accelerometer allows physical activity to be measured quantitatively. Therefore, comparison between different published data is possible. The use of the accelerometer in the clinical practice allows evaluating the outcome of medical and surgical treatment, as so behavior changes. In this study, we report the use of the accelerometer to evaluate the level of activity of 54 Border Collie dogs. The animals were divided in four groups according to their living status: eight animals lived in an apartment (group I), 18 in a house (group II), 11 in a farm (group III) and 17 in a shepherd-training center (group IV). The accelerometer was attached to the animal’s collar for 72 hours. The group I presented longer sedentary behavior than groups II and III. Group IV presented longer sedentary behavior than group III. Group III showed longer period of light-moderate physical activity when compared to group I and IV. For vigorous intensity of physical activity, the time spent by group II was longer than group I. The total time of light-moderate and vigorous physical activity of group I was smaller than groups II and III, while group III was superior to group IV. Group I integrated axis mean counts per minute was smaller than group II and III. Therefore, dogs modify their physical activity according to their living status. Apartment subjects showed less physical activity than home subjects, except in the light-moderate category. There was no statistic difference comparing house and farm living animals, nor apartment and shepherd-training center housing.

Introdução: A tolerância ao exercício e os níveis de atividade física tendem a ser reduzidos em pacientes com fibrose cística (FC). Estudos trazem que o nível de atividade física pode estar associado com melhor estado nutricional e com um maiordeclínio da função pulmonar. Com a evolução da doença,o declínio da função pulmonar associado a distúrbios metabólicos e desnutrição, provocam alterações na mecânica respiratória, distúrbios musculoesqueléticos e deformidades torácicas, trazendo prejuízos na qualidade de vida destes indivíduos. Objetivo: Verificar a associação entre gravidade funcional pulmonar, nível de atividade física e variáveis de avaliação postural em adultos com FC. Secundariamente, verificar a correlação entre os parâmetros de atividade física observados pelo acelerômetro e pelo questionário internacional de atividade física (IPAQ) e, verificar a correlação entre os parâmetros de atividade física observados pelos dois instrumentos com a distância percorrida no teste de caminhada de seis minutos (DTC6M) e os parâmetros de avaliação postural.Métodos: Estudo de caráter transversal, aprovado pelo Comitê de Ética em Pesquisa do Hospital de Clínicas de Porto Alegre. Para a verificação de parâmetros de função pulmonar foi utilizado o exame de espirometria, para a verificação do nível de atividade física foi utilizado o questionário IPAQ e um acelerômetro, para avaliação postural foi utilizada a fotogrametria com auxílio do Software de avaliação postural (SAPO) e, para comparações complementares foi utilizado o teste de caminhada de seis minutos (TC6M). Resultados: Participaram do estudo 28 indivíduos adultos com FC, idade média de 25,1 anos e VEF1 (%) com média de 47,1. O VEF1 se associou com os parâmetros obtidos pelo acelerômetro, avaliação postural e TC6M, porém, não houve associação com os dados obtidos pelo IPAQ. Conclusão: Este estudo demonstrou que o declínio da função pulmonar dos pacientes adultos com FC está associado com maior cifose torácica, menor tempo em atividade física moderada e vigorosa e menor distância percorrida no TC6M. O acelerômetro demonstrou-se ser o melhor instrumento para avaliação da atividade física neste público. / Introduction: Exercise tolerance and levels of physical activity tend to be reduced in patients with cystic fibrosis (CF). Studies suggest that the level of physical activity may be associated with better nutritional status and with larger decline in lung function. With the evolution of the disease, the decline of lung function associated with metabolic disorders and malnutrition, causes alterations in respiratory mechanics, musculoskeletal disorders and thoracic deformities, bringing injury to the individual’s quality of life.Objective: To verify the association between pulmonary functional severity, physical activity level and postural evaluation variables in adults with CF. Secondly, to verify the correlation between the physical activity parameters observed by the accelerometer and the international physical activity questionnaire (IPAQ) and to verify the correlation between the parameters of physical activity observed by the two instruments with the six-minute walking distance (6MWD) and the parameters of postural evaluation. Methods:Cross-sectional study, approved by the Research Ethics Committee of the Hospital de Clínicas, Porto Alegre.The spirometry test was used to verify pulmonary function parameters. The IPAQ questionnaire and an accelerometer were used to assess the level of physical activity, for postural evaluation the photogrammetry was used with the aid of the Postural Evaluation Software (SAPO) and, for further comparisons, the six-minute walk test (6MWT) was used. Results: 28 adult subjects with CF, mean age of 25.1 years and FEV1 (%) with a mean of 47.1 participated in the study. FEV1 was associated with the parameters obtained by the accelerometer, postural evaluation and 6MWT, but there was no association with the data obtained by IPAQ. Conclusion: This study demonstrated that the decline in lung function in adult patients with CF is associated with higher thoracic kyphosis, shorter time in moderate and vigorous physical activity, and shorter distance walked on 6MWT. The accelerometer has been shown to be the best instrument for assessing physical activity in this public.

No description available.

Made available in DSpace on 2014-12-17T14:56:18Z (GMT). No. of bitstreams: 1 AndersonBNS_DISSERT.pdf: 1465627 bytes, checksum: c03d80fd5309916ed15fcc6c0a45c8a8 (MD5) Previous issue date: 2013-10-07 / No espa?o tridimensional, um corpo r?gido qualquer pode efetuar transla??es e ou rota??es em rela??o a cada um de seus eixos. Identificar com precis?o o deslocamento realizado por um corpo ? fundamental para alguns tipos de sistemas em engenharia. Em sistemas de navega??o inercial tradicionais, utilizam-se aceler?metros para reconhecer a acelera??o linear e girosc?pios para reconhecer a velocidade angular registrada durante o deslocamento. O girosc?pio, entretanto, ? um dispositivo de custo mais elevado e com alto consumo de energia quando comparado a um aceler?metro. Essa desvantagem deu origem a pesquisas a respeito de sistemas e unidades de medidas inerciais que n?o utilizam girosc?pios. A ideia de utilizar apenas aceler?metros para calcular o movimento linear e angular surgiu no in?cio da d?cada de 60 e vem se desenvolvendo atrav?s de modelos que variam no n?mero de sensores, na maneira como estes s?o organizados e no modelo matem?tico que ? utilizado para derivar o movimento do corpo. Esse trabalho prop?e um esquema de configura??o para constru??o de uma unidade de medida inercial que utiliza tr?s aceler?metros triaxiais. Para identificar o deslocamento de um corpo r?gido a partir deste esquema, foi utilizado um modelo matem?tico que utiliza apenas os nove sinais de acelera??o extra?dos dos tr?s sensores. A proposta sugere que os sensores sejam montados e distribu?dos em formato de L . Essa disposi??o permite a utiliza??o de um ?nico plano do sistema de coordenadas, facilitando assim a instala??o e configura??o destes dispositivos e possibilitando a implanta??o dos sensores em uma ?nica placa de circuito integrado. Os resultados encontrados a partir das simula??es iniciais demonstram a viabilidade da utiliza??o do esquema de configura??o proposto