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Zhao, Dongning. "A low-noise CMOS interface for capacitive microaccelerometers". Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31715.
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The high-performance accelerometers with micro-gravity resolution and large dynamic range at very low frequencies are not only used in GPS-augmented inertial navigation, monitoring of aircrafts and space station, but also used in monitoring wind turbines for green energy. This dissertation presents the design and development of a mixed-signal, low-noise, and fourth-order sigma-delta interface circuit for the MEMS capacitive micro-gravity accelerometer. A fully-differential switched-capacitor (SC) amplifier architecture is developed with the low-frequency noise reduction through the integration of chopper-stabilization technique with lateral BJT at input stage. The effectiveness of different noise reduction techniques is also compared and verified. The application of fourth-order SC sigma-delta modulation concept to the inertial-grade accelerometer is to achieve the benefits of the digitization of the accelerometer output without compromising the resolution of the analog front-end. This open-loop interface provides 1-bit digital output stream and has the versatility of interfacing sensors with different sensitivities while maintaining minimum power dissipation and maximum dynamic range. The micromechanical accelerometers are fabricated in thick silicon-on-insulator (SOI) substrates. The accelerometer operates in air and is designed for non-peaking response with a bandwidth of 500 Hz.
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Pember, Andrew. "A micromachined silicon accelerometer". Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294739.
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MORIKAWA, SERGIO RICARDO KOKAY. "TRIAXIAL BRAGG GRATING ACCELEROMETER". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5413@1.
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AGÊNCIA NACIONAL DE PETRÓLEOTRANSMISSÃO DE ENERGIA ELÉTRICA S.A
Desde o final da década de 80 a indústria de fibras óticas têm passado por avanços consideráveis. Através de técnicas controladas, as fibras ópticas podem gerar sinais associados a uma vasta gama de grandezas físicas funcionando como sensores denominados de Sensores a Fibra Óptica (SFO s). Diversas técnicas podem ser empregadas para tal, e entre as existentes a baseada em redes de Bragg é a que mais tem se destacado. O interesse por transdutores empregando esta técnica se justifica pelas vantagens proporcionadas pelo uso da luz, tais como sua capacidade de multiplexação, boa relação sinal/ruído, medições a longas distâncias, imunidade a campos eletromagnéticos, ausência de faísca, entre outras. Neste trabalho buscou-se desenvolver um transdutor e uma técnica de medição baseada em sensores a rede de Bragg para medição de vibrações mecânicas. Um acelerômetro óptico triaxial é projetado e construído. Diferentes modelos foram testados em busca das características de desempenho desejadas. Simulações numéricas empregando o método dos elementos finitos auxiliaram na decisão por melhores desenhos para o transdutor. Resultados de testes experimentais e calibrações empregando um sistema de aquisição de sinais desenvolvido são mostrados. Medições de longa duração para avaliação de estabilidade do sistema e efeitos de temperatura também são apresentados.
Since the end of the 1980s, the fiber optics industry has experienced considerable advances. Through a number of controlled techniques, fiber optics can generate signals associated with a vast array of physical measures, working as sensors denominated Optical Fiber Sensors (OFS s). Many different techniques can be employed to achieve this objective. Among these, the one based on Bragg networks has received the greatest amount of attention. The interest in transducers employing this technique is justified by the advantages of using light, such as its multiplexing capability, good signal-to-noise ratio, possibility of long distance measurements, immunity to electromagnetic fields, and absence of sparks. In the present work, a transducer and measurement technique based on Bragg network sensors vibration are developed, in order to measure mechanical vibrations. A triaxial optical accelerometer is designed and built. Different models are tested in the search for the desired performance characteristics. Numerical simulations employing the finite element method help the decision making process for better transducer designs. Results from experimental and calibration tests using a newly developed signal acquisition system are presented. Long duration measurements to evaluate system stability and temperature effects are also shown.
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Olcott, Joanne E. "Fiber-optic flexural disk accelerometer". Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26545.
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Lubratt, Mark Paul. "A voltage-tunable microfabricated accelerometer". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/37497.
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Gibbons, Kevin A. (Kevin Augustine). "A micromechanical silicon oscillating accelerometer". Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43330.
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Loh, Nin C. (Nin Chin) 1977. "High-resolution micromachined interferometric accelerometer". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/89324.
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Kampen, Robertus Petrus van. "Bulk-micromachined capacitive servo-accelerometer". [Delft] : Delft University Press, 1995. http://books.google.com/books?id=LHJTAAAAMAAJ.
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Baker, James. "Dead reckoning using an accelerometer". Thesis, Baker, James (2014) Dead reckoning using an accelerometer. Other thesis, Murdoch University, 2014. https://researchrepository.murdoch.edu.au/id/eprint/25673/.
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The project aim was to develop a technology that would provide a way of navigating when GPS signals could not be used. This includes tunnels, inside buildings and in the city. The proposed solution was to use a dead reckoning (an out dated method of navigating) to navigate using an accelerometer to detecting movement.
The accelerometer acceleration samples would be double integrated to work out distance travelled in each direction. That is up and down, left and right, forward and backwards. A microcontroller would be used to control the device as well as an LCD screen and memory (EEPROM). The controller would be able to store the data to memory allowing it to imported into Excel after an experiment where the data can be manipulated.
In the end a prototype was build but failed to produce accurate calculations. The accelerometer values were hard to calibrate and therefore small errors would encroach on the data. This caused huge problems when integrating and seemed to magnify the error. The prototype would then insist that it has travel vast distances when in fact it has barely moved or not moved at all.
At the end of this document there are future recommendations. First of foremost, the calibration needs to be more accurate if the prototype to work. The two keys ways this would happen is if more samples could be taken to calibrate the accelerometer and/or the calibration value could have more decimal places.
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Tidwell, Robert S. Jr. "An Accelerometer-based Gesture Recognition System for a Tactical Communications Application". Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc822779/.
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In modern society, computers are primarily interacted with via keyboards, touch screens, voice recognition, video analysis, and many others. For certain applications, these methods may be the most efficient interface. However, there are applications that we can conceive where a more natural interface could be convenient and connect humans and computers in a more intuitive and natural way. These applications are gesture recognition systems and range from the interpretation of sign language by a computer to virtual reality control. This Thesis proposes a gesture recognition system that primarily uses accelerometers to capture gestures from a tactical communications application. A segmentation algorithm is developed based on the accelerometer energy to segment these gestures from an input sequence. Using signal processing and machine learning techniques, the segments are reduced to mathematical features and classified with support vector machines. Experimental results show that the system achieves an overall gesture recognition accuracy of 98.9%. Additional methods, such as non-gesture recognition/suppression, are also proposed and tested.
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Mathie, Merryn Joy Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Monitoring and interpreting human movement patterns using a triaxial accelerometer". Awarded by:University of New South Wales. School of Electrical Engineering and Telecommunications, 2003. http://handle.unsw.edu.au/1959.4/27386.
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This thesis addresses the hypothesis that a single, waist-mounted triaxial accelerometer (TA) can be used to monitor human movement patterns in unsupervised, freeliving subjects over extended periods, and that it can be used to quantitatively measure parameters that can provide clinical insight into the health status of the subject. A rigorous theoretical and experimental understanding of the signals obtained from a TA is developed. The effect of the placement of the TA device on the waist is explored and a model relating device position to TA signal is developed for a range of postures and activities. A classification framework for movement identification using the signals from a waist-mounted TA is presented. This framework is based on a hierarchical binary processing tree and is designed for real time use. An implementation of this framework for monitoring housebound patients is presented. Algorithms for detecting falls, distinguishing between activity and rest, classifiying transitions between different postural orientations, and for identifying periods of standing, sitting, lying and walking are developed. In evaluation studies performed in controlled laboratory conditions, every algorithm performed with better than 90% accuracy. Once movements are identified, movement-specific parameters sensitive to changes in functional status are extracted from the signal. A two stage methodology for employing the accelerometry system in monitoring free-living subjects is introduced. The first stage involved monitoring specific movements through a directed routine. The second stage involved monitoring of free movement. Signals obtained from the directed routine are used to extract clinically relevant, movement-specific parameters. Signals obtained from the period of free movement are monitored for falls and other abnormal events. General parameters of movement, including energy expenditure, are also measured. The system was evaluated in a series of field studies in laboratory and home environments, in supervised and unsupervised settings, using cohorts of healthy subjects. A pilot trial was conducted in which six healthy elderly subjects wore the TA device for a period of up to three months. The technical performance and useability of the system were evaluated. Clinically significant parameters were measured and the effects of age and health status on the measured parameters were evaluated.
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Boga, Biter. "Modelling And Noise Analysis Of Closed-loop Capacitive Sigma-delta Mems Accelerometer". Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610772/index.pdf.
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This thesis presents a detailed SIMULINK model for a conventional capacitive Σ
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accelerometer system consisting of a MEMS accelerometer, closed-loop readout electronics, and signal processing units (e.g. decimation filters). By using this model, it is possible to estimate the performance of the full accelerometer system including individual noise components, operation range, open loop sensitivity, scale factor, etc. The developed model has been verified through test results using a capacitive MEMS accelerometer, full-custom designed readout electronics, and signal processing unit implemented on a FPGA. Conventional accelerometer system with force-feedback is used in this thesis. The sensor is a typical capacitive lateral accelerometer. The readout electronics form a 2nd order electromechanical &
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modulator together with the accelerometer, and provide a single-bit PDM output, which is decimated and filtered with a signal processing unit, software implemented on a FPGA. The whole system is modeled in MATLAB-SIMULINK since it has both mechanical and electrical parts. To verify the model, two accelerometer systems are implemented. Each accelerometer system is composed of a MEMS accelerometer, readout circuit, and decimation filters. These two different designs are implemented and simulation and test results are compared in terms of output noise, operational range, open loop sensitivity, and scale factor. The first design operates at 500 kHz sampling rate and has 0.48 V/g open-loop sensitivity, 58.7 µ
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Hz resolution, ±
12g operation range, and 0.97*10-6 g/(output units) scale factor, where these numbers are in close agreement with the estimated results found with simulations. Similarly, the second design operates at 500 kHz sampling rate and has 0.45 V/g open-loop sensitivity, 373.3 µ
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Hz resolution, ±
31g operation range, and 2.933*10-6 g/(output units) scale factor, where these numbers are also close to the estimated results found with simulations. Within this thesis study, an accelerometer sensing element design algorithm is also proposed which is based on the theoretical background obtained in accelerometer system SIMULINK model. This algorithm takes the requirements of the desired accelerometer as input and outputs the dimensions of the minimum noise accelerometer satisfying these requirements. The algorithm is extended to design three different accelerometer structures. An accelerometer sensing element is designed using the proposed design algorithm and tested in order to see performance matching of the algorithm. The designed accelerometer has ±
33.02g operational range and 155µ
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Hz noise where these numbers matches with the values found by the algorithm
13
Säll, Joel, i Johnny Merkel. "Indoor Navigation Using Accelerometer and Magnetometer". Thesis, Linköpings universitet, Institutionen för systemteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-71277.
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This project will create a navigation system based on dead reckoning using anaccelerometer and a magnetometer. There have previously been several studiesmade on navigation with accelerometers, magnetometers (electronic compass) andgyros. With these three components it is possible to do positioning and differentkinds of movement analyses. There are several methods for detection of movementand calculation of position. To achieve greater accuracy in these applications,gyros are often used. Compared to magnetometers and accelerometer gyrosconsumes a lot of power. In an embedded system with limited power suppliesfrom a battery this may be unacceptable. In this project a positioning system without a gyro have been developedand evaluated. Is this possible to do, and what accuracy is possible to achieve arequestions asked.Algorithms have been developed and tested in MATLAB. The project is based ona device called a BeeBadge, part of the project will be to transfer the developedalgorithms from MATLAB to C-code. Optimizations of the code will be performeddue to the constraints in the memory and speed of the microcontroller on theBeeBadge.
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Westerholm, Glenn. "Kadenssensor med en accelerometer och ANT+". Thesis, Linköpings universitet, Datorteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119070.
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Rapporten presenterar det examensarbetet som har gått ut på att undersöka möjligheterna att konstruera en sensor som mäter kadens med hjälp av en accelerometer. Implementation av kadensprofilen till ANT+ har gjorts för att möjliggöra synkronisering mellan en sportklocka och sensorn. Kadens är hur fort cyklisten trampar med pedalerna mätt i enheten Varv per minut vanligt förkortat RPM från engelskans Revolutions Per Minute. Hur fort en cyklist trampar påverkar kroppen på många olika sätt och ofta vill cyklisten veta vad aktuell kadens är för att optimera sin prestation. Den undersökta principen att använda en accelerometer för att mäta kadens syftar till att en eventuell prototyp skulle vara lämplig till inomhuscykling även kallad spinning. På en vanlig traditionell cykel har man oftast två hårdvarudelar för att mäta kadens, en monterad på pedalarmen och den andra på cykelramen. Cykelramen på en spinningcykel skiljer sig så pass mot en vanlig cykel att hårdvarudelen som ska sitta på cykelramen inte kan monteras med samma lätthet. Med en accelerometer behövs bara en hårdvarudel som lätt kan monteras på pedalarmen på cykeln. Programutvecklingen har skett med ett Arduino Uno som består av en ATmega328 mikrokontroller från Atmel. Sensorenheten som mäter kadensen består av Arduino Uno, accelerometern LSM303DLHC från STMicroelectronics och ANT-chippet nRF24AP2 från Nordic Semiconductor. Huvudenheten har bestått av en persondator som har agerat mottagare med programmet ANT+ Simulator. Det utvecklade programmet på mikrokontrollen upptäcker när det sker ett pedalvarv och skickar den totala varvtiden tillsammans med antal pedalvarv som totalt inträffat till nRF24AP2 vidare till huvudenheten. Kadensprofilen är den som räknar ut vad aktuell kadens är. Avslutningsvis presenteras ett minimumkrav av hårdvaran och ett förslag av en energisnål mikrokontroller för en eventuell prototyp.
15
Sjöström, Henrik. "DeepConvLSTM on single accelerometer locomotion recognition". Thesis, Umeå universitet, Institutionen för datavetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-142516.
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This project aims to evaluate the deep neural network architecture Deep-ConvLSTM to classify locomotive human activities using data from a single accelerometer. The evaluation involves comparisons to a simpler convolutional neural network and a hyperparameter evaluation in regards to the networks number of convolutional layers. The benchmark OPPORTUNITY dataset is used for training and evaluation from which triaxial accelerometer data from hips and legs are extracted. The results of the evaluation suggests that DeepConvLSTM outperforms simpler models on most locomotive activity recognition, especially at filtering out unclassified data. Further the results show that DeepConvLSTMs performance improves with a higher number of convolutional layer, but the number of limited by the architectures lack of padding and is compensated by longer training times.
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Kaiser, Todd Jeffrey. "A micromachined pendulous oscillating gyroscopic accelerometer". Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/13729.
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Ashburn, Michael Anthony. "A high precision fully integrated accelerometer". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/40585.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 193-196).
by Michael Anthony Ashburn, Jr.
M.S.
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Butts, David LaGrange. "Development of a light force accelerometer". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46568.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2008.Includes bibliographical references (p. 93-96).
In this work, the feasibility of a light force accelerometer was experimentally demonstrated. The light force accelerometer is an optical inertial sensor which uses focused laser light to levitate and trap glass microspheres as proof masses. Acceleration is measured by force rebalancing, which is exerted by radiation pressure from two counter-propagating laser beams. Proof mass displacements are measured by focusing light scattered by the proof mass on a position-sensitive photodetector. A simple model including laser relative intensity noise and shot noise from the measurement of the trapping beam powers estimates that the light force accelerometer could be capable of achieving a sensitivity of < 100 ng/Hz1/2. Essential components of this optical accelerometer, including the levitation of 10 pm glass microspheres in high vacuum and optical force rebalancing, were demonstrated with a single laser beam levitating a microsphere against gravity. Levitated particles are unstable in vacuum because of low viscous forces, so feedback stabilization is necessary for long term trapping. Preliminary performance diagnostics tested the short term sensitivity and bias stability of the apparatus for a constant 1 g acceleration. The factors currently limiting these performance parameters were determined to be bias instabilities associated with measurement of proof mass position and long term biases due to pressure-dependent radiometric effects. Proposed modifications to the current apparatus include the implementation of a two-beam light force accelerometer and a more precise particle position detection method which is less sensitive to proof mass irregularities. This two-beam configuration enables operation in any orientation and permits complete characterization of accelerometer performance. Steps to develop a compact light force sensor in the future are also suggested.
by David LaGrange Butts.
S.M.
19
Guo, Fei. "Micromachined capacitive accelerometer with crab-shape". Thesis, Cape Peninsula University of Technology, 2005. http://hdl.handle.net/20.500.11838/1282.
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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2005Perhaps more popular than the piezoresistive type are the capacitive type of micromachined accelerometers. The capacitive accelerometer has many fine characteristics, such as simple structure, high sensitivity, strong ability of resisting disturbance, fast dynamic response and so on. It can also work under abominable condition. So it is occupying an important status in the technology of electronical measurement and being used in many kinds of metrical systems. In this paper, the capacitive accelerometer (CA) we will introduce and design is a parallel plate CA with crab-shape. It will detect the acceleration signal by the change of distance between two electrode plates, and its design standard came from the industrial requirements ofKENTRON Company. The whole paper can be divided into four main phases-introduction, study, design and analysis. At first, we have introduced the purpose and background of this thesis, and then the study and the discussion of relative literature. The content of these articles is mainly about the basic principle, types and applications of micro-sensors and this information will be very helpful to the design and analysis ofmy own CA. The course of design is primarily structure design. The main structures of CA are parallel plate structure and cylinder structure. The parallel plate structure is chosen for our CA after we did the comparison of performance and technique of making between these two types of structures. We use the concentrative mass as the top electrode plate and four beams are connected on the two sides of the plate separately.
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Zhang, Rui. "Mechanics of micromachined bridge-type accelerometer". Thesis, Cape Peninsula University of Technology, 2005. http://hdl.handle.net/20.500.11838/1285.
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Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2005Having simple structure and high sensitivity, micro accelerometer is a type of popular transducer used to measure the acceleration in a great variety of conditions. The bridge-type micro accelerometer is a typical micro accelerometer and has many types. As one of research project of Kentron in South Africa, the thesis presented here analyzes the bridge-type capacitive nticro accelerometer (BTCMA) and the bridge-type micro accelerometer with two piezoelectric thin films read-out (BTPMA). In this thesis, the similar structures are used on BTCMA and BTPMA For proving the fundamental mode of the structure can measure acceleration and utilizing the structural and electric characteristic to avoid the effect of higher modes, the program CoventorWare for nticro-electric-mechanical system (MEMS) design and analysis is used here to analyze the modes of these two structures, The two group piezoelectric thin films of BTPMA can be connected in serial or parallel configurations. Integrating piezoelectric effect method, strength method and energy method, the analytical analysis of these two configurations has been done with particular emphasis on the elastic characteristics of the thin films. The analytical formulas of transducer, sensitivity, resonance frequency, noise, quality factor, ntinimum detectable signal and maximum detectable range are obtained. According to the comparison results between these two configurations, the charge output in parallel configuration is a little more than that in serial configuration and the sensitivity in serial configuration is much higher than that in parallel configuration. Finally, a calculation of certain practical nticro accelerometer size is used to prove the above conclusions. On the base of capacitance theory, strength method and energy method, the analytical analysis of the BTCMA has been done in this thesis.
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Young, Jonathan C. "Vibration analysis using a MEMS accelerometer". Thesis, Monterey California. Naval Postgraduate School, 2006. http://hdl.handle.net/10945/2409.
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The primary objective of this these was to study the feasibility of using a MEMS accelerometer to monitor vibration signatures of a machine to determine if the machine is operating properly. The secondary objective was to investigate the self test features of the accelerometer used in the vibration monitoring. An Efector Octavis accelerometer sensor was used in this study. It was used to monitor a small air pump and an air conditioning (AC) system. The sensor provided the amplitude for the frequency spectrum of the motor vibration. A reference signal was calculated by taking an average of the spectrum over 30 seconds. Two methods (a ratio of cross-correlation coefficients and a spectral distance) were used to compare the reference to the sensor data. The spectral distance method proved to be the better of the two. Using this method, the system could sense when the pump or the AC unit were malfunctioning. The self test feature involved exciting the Built in Self Test (BIST) pin of the accelerometer with a signal generator. Then the impulse response of the accelerometer was measured from the output pin using an oscilloscope.
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Alsaedi, Mohammed Abbas Soudai. "Development of 3D Accelerometer Testing System". PDXScholar, 2016. https://pdxscholar.library.pdx.edu/open_access_etds/3371.
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Accelerometers are used in numerous industries including aircrafts and missile navigations systems, rotary machines, and electronic devices such as tablets, cell phones, and cameras. Accelerometers of different purposes and specifications are being produced in large quantities. The large demand for accelerometers forces the need for accelerometer testing methodology that is more convenient and accurate. Inertial Micro-Electromechanical Systems Accelerometer (MEMS) require a series of tests that include physical stimuli. One of the key challenges is the cost associated with testing. Therefore, the accurate prediction of the sensor functions not only reduces the testing time but also more importantly contributes to reducing testing cost.
Shaker accelerometer calibrators are widely used to test accelerometers. Shakers use sinusoidal acceleration input, and their testing acceleration range could be as small as 0.1 g1 and as high as 20 g. These devices test accelerometers in one axis at a time. In this study, the 3-D MEMS accelerometer testing method and system have been developed to reduce the testing time cycle significantly by testing 3D axes simultaneously. The theoretical study shows that an acceleration sensor is rotating about a fixed axis experiences tangential and normal accelerations.
The objective of this project is to develop a testing methodology and equipment to test accelerometers along all three axes simultaneously over a range of ± 50 g while reducing testing time. These accelerations are related to the distance from the center of rotation and the angular velocity. The angular velocity can be controlled by the amount of the voltage that is given to the DC motor from the power supply which is adjusted by a speed controller. By varying either the angular velocity with the speed controller or varying the distance from the axis of rotation, it is possible to expose an accelerometer to the desired acceleration value.
The equipment uses a rotating turntable where the center of the table marks the axis of the rotation. The accelerometer being tested was mounted at a known distance from the center of the table. The resulted normal and tangential accelerations were calculated from the angular velocity of the turntable and the position of accelerometer from the axis of rotation. A high precision encoder was used to determine the angular velocity of the turntable. The range of the angular velocity that can be measured accurately by the encoder affects the range of acceleration amplitude the system can be used to test. The encoder used can sense an angular velocity as low as 0.0144º/s. This corresponds to the normal acceleration value of 2.32 x 10-9 g.
The accelerometer mounted on a turntable in a way that all three of its axes are exposed to the input acceleration to test an accelerometer in all three axes at the same time. A program written in LabVIEW operated the system and collected the test data. This program was able to collect acceleration readings along all three axes of the accelerometer with position and velocity information of the input motion. The collected data set were processed by MATLAB. This testing methodology provides a way to use multiple input accelerations unlike traditional accelerometer testing method. The test methodology developed in this study provides a way to use a constant acceleration input over a wide range (± 50 g). Its lowest acceleration range is 2.32 x 10-9 g. This reduces the time it takes to align the accelerometer in different axes and eliminates errors that may result during a manual repositioning of the accelerometer to align it in a different axis. Error models for MEMS accelerometer sensors have used Kalman filters to perform complete accelerometer sensor test.
The accelerometer error model must be constructed, and the coefficients in the error equations must be determined. Therefore, Kalman filter in the analysis of visual motion has been documented frequently. The filter is constructed as a mean squared error minimizer. The purpose of filtering is to extract the required information from a signal, ignoring everything else.
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Godhe, Manne, i Victor Stoltz. "GT3X - En valideringsstudie av en ny accelerometer". Thesis, Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:gih:diva-1158.
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Syfte och frågeställningar
Syftet med denna studie är att validera accelerometern GT3X. Utifrån detta syfte formulerades följande frågeställningar:
- Hur väl kan GT3X uppskatta energiutgift på olika intensiteter?
- Har kroppsplaceringen av GT3X någon betydelse för dess förmåga att uppskatta energiutgift?
- Vilka är gränsvärdena för GT3X-counts relaterat till METs?
Metod
9 kvinnor och 18 män (ålder: 22-36 år) gick och joggade på ett löpband (3 km/h, 4,9 km/h, 8 km/h och 10 km/h) och utförde ett steptest (180 BPM). GT3X bars på fem olika placeringar (höger överarm, ländrygg, höger fotled, höger handled samt höger sida på höften) samtidigt, i syfte att beräkna energiutgift, insamlades data om försökspersonens in- och utandningsluft med ett syreupptagningsmätningssystem. Korrelationen mellan vardera accelerometerplacering (överarm, ländrygg, fotled, handled, höft) och uppmätt energiutgift beräknades genom ett bivariat korrelationstest. Genom regressionsanalyser fastställdes den bästa prediktorn för total energiutgift, uppmätt med syreupptagningsmätningssystem. Detta gjordes för låga, höga samt blandade intensiteter. Regressionsanalyserna utfördes med hänsyn till accelerometervektorer, vikt, längd och isättningar. I samtliga regressionsanalyser plockades även puls med, i ett separat steg.
Resultat
Samtliga placeringar visade hög korrelation, mellan GT3X-counts och uppmätt energiutgift, på låga intensiteter (rö.arm= 0, 840, rländrygg= 0,832, rfotleden= 0,790, rhandled= 0,789, rhöft= 0,801) samt över hela intensitetsspannet sammantaget (rö.arm= 0,704 rländrygg= 0,749 rfotleden= 0,600 rhandled= 0,642 rhöft= 0,716). På höga intensiteter visades, för samtliga placeringar, ett svagt negativt samband (rö.arm= -0,109, rländrygg= -0,086, rfotleden= -0,122, rhandled= -0,189, rhöft= -0,074) mellan GT3X counts och uppmätt energiutgift. På samtliga intensiteter kunde GT3X, tillsammans med övrig data, förklara upptill 87,1 % av variationer av uppmätt energiutgift (R2=0, 871).
Slutsats
GT3X är ett valitt mätinstrument för uppskattning av energiutgift på låg- samt blandad intensitet. Vid måttlig till hög intensitet är GT3X beroende av puls, för att uppnå samma höga förklaringsgrad. Placeringen av GT3X har en marginell betydelse vid uppskattning av energiutgift, detta gäller oavsett intensitet. Gränsvärdena för GT3X counts relaterat till METs varierar beroende på placering.
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Jung, Changsu. "Measuring movement of golfers with an accelerometer". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105144.
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The purpose of this thesis is to analyze a golfer’s movement and provide the feedback related to the golfer’s skill with the simple and novel ways. A golfer can easily measure golf swings and get feedback based on his performance using an Android smart phone without expensive or complicated devices. In this thesis, we designed and implemented an Android application using an accelerometer sensor to analyze swing data for identifying critical points and to give various kinds of feedback based on the data. The feedback helps golfers to understand their swing patterns, timing and speed so it makes them improve their skills.
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Mui, Man Kit. "Development and characterization of PCB-based accelerometer /". View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?MECH%202007%20MUI.
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Kraft, Michael. "Closed loop digital accelerometer employing oversampling conversion". Thesis, Coventry University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361662.
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Sivapiragasam, Sanjivan. "Accelerometer calibration of shuttle-based experiment packages". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/42509.
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Needham, Richard Lee. "Calibration of strapdown system accelerometer dynamic errors". Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/47358.
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Majala, Jonas. "Frequency analysis of accelerometer measurements on trains". Thesis, Luleå tekniska universitet, Geoteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63930.
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Diaz, Jason McMurray Robert G. "Calibration of the Actical accelerometer in adults". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2201.
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Thesis (M.A.)--University of North Carolina at Chapel Hill, 2009.Title from electronic title page (viewed Jun. 26, 2009). "... in partial fulfillment of the requirements for the degree of Master of Arts in the Department of Exercise and Sport Science Exercise Physiology." Discipline: Exercise and Sports Science; Department/School: Exercise and Sport Science.
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Metcalf, Kristen M. "Accelerometer positioning issues and contemporary analysis methods". Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6210.
Pełny tekst źródłaStreszczenie:
Purpose: Accelerometry is commonly used to objectively measure physical activity (PA), however, differential data collection methods and analysis techniques yield dissimilar outcomes. The aims of this research were to (1) understand how accelerometer output varies among accelerometers worn on the non-dominant wrist (NDW), dominant wrist (DW), and hip; (2) develop site-specific algorithms to predict activity type classification, activity intensity classification, and estimates of metabolic intensity; and (3) compare the algorithms in a free-living setting.
Methods: Forty participants (16.8 – 64.2 yr) completed a sequence of sedentary and physical activities in a laboratory while wearing accelerometers on the NDW, DW, and hip. Participants also wore a portable metabolic analyzer to objectively measure oxygen consumption (VO2). One-second accelerometer output was compared across wear locations by activity type and intensity classifications (Aim 1). Accelerometer output data were transformed into variables related to the magnitude (ϒ), horizontal angle (φ), and inclination (θ) of acceleration, and used to develop algorithms for the NDW, DW, and hip. Random forest algorithms were developed to predict activity type classification (i.e., sedentary, lifestyle, and ambulatory) and activity intensity classification (i.e., sedentary, light, moderate, and vigorous), and regression models were built to predict VO2 (Aim 2). Following the laboratory visit, participants simultaneously wore an accelerometer at each of the three locations for three days of free-living data collection. The site-specific algorithms developed in Aim 2 were compared for equivalence (Aim 3).
Aim 1 Results: Analysis of variance indicated that accelerometer output differed between the NDW, DW, and hip for all activities completed, except for lying supine. Differences were expected; thus, Pearson correlation coefficients were calculated between the NDW, DW, and hip, and compared across activity type and intensity classifications. For activity type, the relationships between all wear locations were different for all activity types (i.e., sedentary, lifestyle PA, and ambulatory PA). For activity intensity, the relationships between the wrists were significantly different between sedentary and light activities. Additionally, relationships between the NDW, DW, and hip differed between light and moderate, and light and vigorous PA for all wear locations. The disparate correlations indicated that accelerometer signals do not just increase in magnitude as intensity increases; rather they increase differentially by wear location and activity type.
Aim 2 Results: Site-specific random forest algorithms were developed to predict activity type and intensity classification. The algorithms utilized 10-15 features of the accelerometer signal related to variability, location, and central tendency. The hip had prediction accuracies of 84.9% for activity type classification and 80.2% for activity intensity classification. The dominant wrist had activity type prediction accuracy of 83.6% and intensity prediction accuracy of 78.9%. The non-dominant wrist had prediction accuracies of 83.1% and 78.0% for activity type and intensity, respectively. The VO2 prediction algorithms had Mean Absolute Errors of 2.96 ml/kg/min for the hip, 3.34 ml/kg/min for the NDW, and 3.49 ml/kg/min for the DW. This equates to an average error of 0.93 metabolic equivalents (METs); algorithms currently used in practice yield errors of 0.89 to 2.00 METs.
Aim 3 Results: The site-specific prediction algorithms were applied to free-living data. Using the random forest algorithms, activity type classification estimates differed by 2 to 82 minutes/day, and activity intensity classification estimates differed by 0 to 83 minutes/day; however, these differences were not significantly different. The VO2 prediction models provided estimates of PA within 0 to 57 minutes/day of one another. The hip provided the lowest estimates of MVPA, while the NDW provided the highest estimates, however the VO2 estimates from all wear locations were statistically equivalent to one another.
Conclusion: The differential relationships among accelerometer outputs from the NDW, DW, and hip indicate that output differs based on activity type and intensity. This non-systematic error prevents scaling or comparing data collected at different wear locations and supports the need for site-specific analysis methods. Site-specific prediction algorithms provided comparable to improved performance over currently-utilized analysis methods in PA research, and the PA estimates were equivalent across wear locations. This research provides a more nuanced understanding of the impact of wear location on accelerometer output and alternative methods for analysis. Importantly, the algorithms created allow for comparisons to be made among data collected at the NDW, DW, and hip, which has not previously been possible.
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Mills, Euclid Weatley. "Mobile robotic design : robotic colour and accelerometer sensor". Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4436.
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This thesis investigates the problem of sensors used with mobile robots. Firstly, a colour sensor is considered, for its ability to detect objects having the three primary colours Red, Green and Blue (RGB). Secondly, an accelerometer was investigated, from which velocity was derived from the raw data using numerical integration. The purpose of the design and development of the sensors was to use them for robotic navigation and collision avoidance. This report presents the results of experiments carried out on the colour sensor and the accelerometer. A discussion of the results and some conclusions are also presented. It proved feasible to achieve the goal of detecting colours successfully but only for a limited distance. The accelerometer proved reliable but is not yet being applied in real time. Both the colour sensor and the accelerometer proved to be inexpensive. Some recommendations are made to improve both the colour sensor and the accelerometer sensors.
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Coultate, John. "Optimal and robust design of a MEMS accelerometer". Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438643.
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FORSS, ANTON. "Verifiering av accelerometer mätning i 16-bitars mikrokontroller". Thesis, KTH, Produkt- och tjänstedesign, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-249712.
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Denna rapport är ett examensarbete vid institutionen för mekatronik vid KTH. I arbetet jämförs två metoder för utveckling och verifiering av en algoritm för accelerationsanalys i en mikrokontroller (sedarmera förkortat µC). En µC av typ MSP430G2553 används som målsystem. Målet med algoritmen är att µCn skall kunna särskilja rekylacceleration från andra accelerationer som slag och mekanismrörelse i ett vapen. I arbetet presenteras två metoder för utveckling och verifiering. Alternativ 1 använder endast målsystemet och dess mjukvaruverktyg. Alternativ 2 använder målsystem och mjukvaruverktyg men också ett kombinationsinstrument med både oscilloskop-funktion och arbiträr-vågforms-generator. I rapporten undersöks också två olika accelerometrar samt två varianter av µC. Med hjälp av kombinationsinstrument kunde flertalet referensmätningar genomföras av vapnets acceleration vid rekyl. Kombinationsinstrumentet användes också för att simulera accelerationer mot målsystemet. Resultatet av arbetet är att verifiering och utveckling med kombinationsinstrument (alternativ 2) är fördelaktigt ur flera synpunkter. Men att alternativ 1 också besitter flera fördelar. Den främsta fördelen med alternativ 2 är att accelerationsdatat enkelt kunnat samlats in utan beroenden av µCs prestanda eller programmeringsfel. Instrumentet underlättar flera andra delar i utveckling som extern verifiering av programmets exekvering och möjligheten att reproducera tidigare samlad accelerationsdata mot målsystem. Vilket gör kombinationsinstrumentet till ett behändigt utvecklingssystem.This report is a final thesis report at the institution of Mechatronics at KTH (The Royal institute of Technology). In this report two methods for development and verification are compared for acceleration analysis in a weapon with a microcontroller (hence called µC). A µC of type MSP430G2553 is used as target system. The goal of the µC's program is to determine if an acceleration pattern is a recoil or not. In the report two methods are presented for verification and development. Alternative 1 is limited to using the target µC and software tools associated with it. Alternative 2 is using the target µC and software tools but also and additional combination instrument which includes both oscilloscope and arbitrary waveform generator. The combination instrument was used to measure several recoil acceleration patterns. These reference measurements were used to simulate accelerometer for the target system. The conclusion is that alternative 2's use of the combination instrument is of great benefit in several perspectives. Alternative 1's also has several benefits. Furthermore alternative 2 enables early identification of the acceleration data without the limits of the µC as memory constraints and program defects. The combination instrument is a useful tool for development, as it can be used as a small HIL-system
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St, Michel Nathan A. (Nathan Alan) 1975. "Force multiplier in a microelectromechanical silicon oscillating accelerometer". Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/31084.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.Includes bibliographical references (leaves 89-90).
This thesis describes the third generation design of a silicon oscillating accelerometer (SOA.) The device is a micromachined vibrating beam accelerometer consisting of two tuning fork oscillators attached to a large proof mass. When accelerated along the input axis, the proof mass exerts a force on the oscillators, causing their natural frequencies to shift in opposing directions. Taking the difference of these frequencies gives a measurement of the applied acceleration. A significant feature in the new design is a force multiplying lever arm which connects the oscillators to the proof mass. With this addition, the surface area of the proof mass is reduced by a factor of four, while the scale factor and axial resonant frequency of the previous design is retained. All vibration modes of the device are identified, and stiffness nonlinearity in the oscillators is investigated. A method to compensate for thermally induced acceleration errors is also introduced. Testing of the fabricated device is shown to agree with model predictions.
by Nathan St. Michel.
S.M.
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Brooks, Lane Gearle 1975. "Amplitude and frequency demodulation controller for MEMS accelerometer". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8938.
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Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 121-122).
Draper Laboratory is developing a high precision MEMS accelerometer. This thesis describes and analyzes the electronics which produce the acceleration estimate and control the actuators within the sensor. The Vector Readout method of amplitude and frequency demodulation is described and shown to be a high precision, environmentally stable method of demodulation. The Vector Readout method of demodulation uses a Hilbert Transform filter and the CORDIC algorithm to simultaneously estimate both the amplitude and phase of a signal. A feedback controller is designed to hold the oscillation of a mass resonator at a constant amplitude.
by Lane Gearle Brooks.
M.Eng.and S.B.
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Kotru, Krish. "Toward a demonstration of a Light Force Accelerometer". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62486.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 79-81).
The Light Force Accelerometer (LFA) is an optical inertial sensor in which radiation pressure from two counter-propagating laser beams optically confines a glass microsphere. Inertial acceleration of the device results in microsphere displacement along the sensitive axis, which is subsequently nulled by optical forces to provide an acceleration measurement. A simple calculation that takes into account fundamental noise processes in the LFA (i.e., shot noise and RIN in the laser beams) places the sensitivity limit of this accelerometer at < 100 ng. By incorporating widely available, inexpensive optical components into a simple design, a high-precision LFA could provide an appealing alternative to other sensors of comparable performance. Previous work on the LFA revealed instabilities in proof mass position detection caused by the asphericity of microspheres. In this thesis, an alternative method for position detection which was less sensitive to shape-irregularities in microspheres was investigated. Results indicated that resolution of microsphere motion was enhanced significantly when the new detection method was implemented. This improvement. however, did not eliminate the position instabilities observed previously. Capabilities for optical trapping with two counter-propagating beams in air were also developed in this work. Trapping with feedback position control in air was demonstrated for the first time, but long-term trapping in vacuum was prohibitively difficult due to destabilizing mechanical vibrations. For a microsphere in atmospheric pressure, the estimated bias stability was 318 jig after 300 seconds of averaging, and the approximate short-term sensitivity was 500 pg/v/ Hz. Stabilization of mechanical vibrations and precise calibration of power measurements to acceleration will allow this two-beam trap to probe the performance limits of the LFA.
by Krish Kotru.
S.M.
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Song, Wen. "Planetary navigation activity recognition using wearable accelerometer data". Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/15813.
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Master of ScienceDepartment of Electrical & Computer Engineering
Steve Warren
Activity recognition can be an important part of human health awareness. Many benefits can be generated from the recognition results, including knowledge of activity intensity as it relates to wellness over time. Various activity-recognition techniques have been presented in the literature, though most address simple activity-data collection and off-line analysis. More sophisticated real-time identification is less often addressed. Therefore, it is promising to consider the combination of current off-line, activity-detection methods with wearable, embedded tools in order to create a real-time wireless human activity recognition system with improved accuracy. Different from previous work on activity recognition, the goal of this effort is to focus on specific activities that an astronaut may encounter during a mission. Planetary navigation field test (PNFT) tasks are designed to meet this need. The approach used by the KSU team is to pre-record data on the ground in normal earth gravity and seek signal features that can be used to identify, and even predict, fatigue associated with these activities. The eventual goal is to then assess/predict the condition of an astronaut in a reduced-gravity environment using these predetermined rules. Several classic machine learning algorithms, including the k-Nearest Neighbor, Naïve Bayes, C4.5 Decision Tree, and Support Vector Machine approaches, were applied to these data to identify recognition algorithms suitable for real-time application. Graphical user interfaces (GUIs) were designed for both MATLAB and LabVIEW environments to facilitate recording and data analysis. Training data for the machine learning algorithms were recorded while subjects performed each activity, and then these identification approaches were applied to new data sets with an identification accuracy of around 86%. Early results indicate that a single three-axis accelerometer is sufficient to identify the occurrence of a given PNFT activity. A custom, embedded acceleration monitoring system employing ZigBee transmission is under development for future real-time activity recognition studies. A different GUI has been implemented for this system, which uses an on-line algorithm that will seek to identify activity at a refresh rate of 1 Hz.
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Zou, Xudong. "High resolution resonant accelerometer based on MEMS technology". Thesis, University of Cambridge, 2014. https://www.repository.cam.ac.uk/handle/1810/283942.
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羅智德. "MEMS Accelerometer Design". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/13434599323520473766.
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碩士中華大學
機械與航太工程研究所
88
Several kinds of MEMS accelerometers are proposed by using the UMC standard fabrication process. Firstly, the IntelliSuite software package is applied for the process simulation. Secondly, the ANSYS software package is used for the accelerometer proof mass displacement and structural strain and stress simulation. Thirdly, the layout is realized by using Tanner Tools Pro program. Finally, the masks are made by NDL and supported by CIC for fabrication. The proposed MEMS accelerometers are of two types; one is with single capacitor, and the other is with two capacitors for differential mode operation. The operating rang of the accelerometer is under 3 g’s, which can be used for the vertical navigation. The advantage of the differential mode is that the effects due to thermal, aging fatigue and noise can be reduced. By the way, one can further reduce the bias and thermal effects by using the proposed multi-accelerometers structure, one is based on the displacement of proof mass, and the other is made by piezo-resistive principle.
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"CNT-based thermal convective accelerometer". 2009. http://library.cuhk.edu.hk/record=b5894128.
Pełny tekst źródłaStreszczenie:
Zhang, Yu.Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.
Includes bibliographical references (leaves 55-60).
Abstract also in Chinese.
Abstract --- p.i
Acknowledgement --- p.iii
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Background --- p.1
Chapter 1.2 --- Aim of Research --- p.2
Chapter 1.3 --- Thesis Organization --- p.3
Chapter 2 --- Literature Review --- p.4
Chapter 2.1 --- Carbon Nanotubes in MEMS Devices --- p.4
Chapter 2.1.1 --- CNT Integration and CNT sensors --- p.4
Chapter 2.1.2 --- Prior Work in CMNS --- p.6
Chapter 2.2 --- Overview of Motion Sensors --- p.7
Chapter 2.2.1 --- Technology Overview --- p.7
Chapter 2.2.2 --- Categories and Working Principles --- p.9
Chapter 2.2.3 --- Application --- p.13
Chapter 2.3 --- Thermal Convective Motion Sensors --- p.14
Chapter 2.3.1 --- Micro Thermal Flow Sensors --- p.15
Chapter 2.3.2 --- Research on Thermal Convective Motion Sensors --- p.17
Chapter 2.3.3 --- Working Principle and Performances --- p.20
Chapter 3 --- Design and Setup --- p.25
Chapter 3.1 --- Methodology --- p.25
Chapter 3.1.1 --- Research Method --- p.25
Chapter 3.1.2 --- Critical Questions --- p.26
Chapter 3.2 --- Sensor Chip Design and Fabrication --- p.27
Chapter 3.2.1 --- Sensor Chip Mask Design --- p.27
Chapter 3.2.2 --- Fabrication of Sensor Chip --- p.29
Chapter 3.3 --- Sensor Prototyping --- p.30
Chapter 3.3.1 --- CNT Deposition --- p.30
Chapter 3.3.2 --- Sensor Building --- p.32
Chapter 3.4 --- Setup of Experiment --- p.34
Chapter 3.4.1 --- Source and Measure --- p.34
Chapter 3.4.2 --- Acceleration Production --- p.35
Chapter 4 --- Experiments and Results --- p.39
Chapter 4.1 --- Hypotheses Verification --- p.39
Chapter 4.1.1 --- Thermal Detection Using CNT --- p.39
Chapter 4.1.2 --- Local Heating & Sensing --- p.40
Chapter 4.2 --- Tilting Test --- p.42
Chapter 4.2.1 --- Test Result --- p.42
Chapter 4.2.2 --- Result Discussions --- p.43
Chapter 4.3 --- Vibration Test --- p.45
Chapter 4.3.1 --- Test Result --- p.45
Chapter 4.3.2 --- Result Discussions --- p.52
Chapter 5 --- Conclusion --- p.53
Bibliography --- p.55
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Dai, Hung-Da, i 戴宏達. "CMOS-MEMS z-axis accelerometer". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/60731307885686218511.
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Yang, Chih-Jen, i 楊智任. "Using Accelerometer in Vehicle Positioning". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/02247516448136932761.
Pełny tekst źródłaStreszczenie:
碩士國立臺灣海洋大學
機械與機電工程學系
95
In this thesis, the problem of vehicle position estimation using an accelerometer is investigated based on Kalman filtering theory, and a linear motion system is implemented in the experiment to test the performance. In generally, the position estimation problems using accelerometers without any filtering process will become divergent as time elapse. This is because the sensor’s signals inevitably contain a certain extent of noises, and the noises accumulate during the integration process. Hence in order to estimate the position more accurately, Kalman filtering algorithm is usually employed to derive a more reliable result. One of the prerequisites in using Kalman filter is that the information of the process noise covariance and measurement noise covariance should be known in advance in order to derive the best estimation result. The above mentioned noises are generally dependent variables with respect to the motion states. Hence in the thesis, we measured the optimal state noises versus a set of jerk values through the experiments, and then by feeding them into the neural network to memorize the relationship. Then Kalman filter would update the state noise values according to the current motion states during the position estimation experiments. From the experimental result, it showed that the proposed algorithm was proved to be a reliable estimation algorithm.
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Huang, Foo-tsung, i 黃復聰. "Integrated Accelerometer/GPS Heading Estimator". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/74788950055560428429.
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碩士國立臺灣大學
應用力學研究所
89
Based on the idea of Kalman filtering, the heading estimator of a baseline vector integrating accelerometer and Global Positioning System（GPS）is designed in this thesis. The accelerometers not only can provide the acceleration of a vehicle, but also can be used to obtain attitude information of the vehicle by suitable arrangement and integration. For the problem of heading estimation, we may place four sets of one axis accelerometers at both ends of the baseline. By measuring the tangential acceleration and the centripetal acceleration, an extended Kalman filter can be used to compute the heading angle of the baseline vector. On the other hand, using the GPS Carrier-Smoothed-Code（CSC） algorithm, the heading angle estimate can be obtain in the rate of 1Hz. Although the accelerometers can provide the attitude information at a higher sampling rate（e.g. 100Hz）, the accumulation errors due to integration make it necessary to perform adjustment periodically. On the contrary, although GPS estimation has lower sampling rate, it can be used to correct the drifting errors of the accelerometers. To integrate the two systems, a multi-rate filter is designed to obtain the optimal and real-time heading angle estimation. From the simulation results and the experimental results described in this thesis, it is observed that the 2nd order EKF can solve the singularity problem from the nonlinear measurement equation when the angular velocity is close to zero. Moreover, the proposed accelerometer/GPS integrated heading estimator can indeed eliminate the errors from the drift phenomenon, and provide the accurate heading angle estimate of the baseline vector in real time.
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Chang, Ming-Han, i 張銘漢. "Action Recognition with 3D Accelerometer". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/78718632121220097634.
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碩士義守大學
資訊工程學系
102
Mobile devices and human-computer interaction techniques have gained much attention in recent years. Many mobile phone manufacturers have also invested considerable human resources in establishing uniqueness of their own devices. In November 2006, Nintendo released a somatosensory game host, Wii. An unprecedented game mode with the Wii Remote is equipped with a three-dimensional accelerometer. This accelerometer can be used as an action recognition, and returns a message to the host. Three-dimensional accelerometer can be applied to different aspects including digital teaching, appliance control, home security monitoring, medical rehabilitation, etc. The purpose of this study is based on the remote control to analyze the composition of continuous signals. Signals are converted into strings, and then compared with a predefined codebook to achieve the action recognition.
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Zheng, Yonglei. "Predicting activity type from accelerometer data". Thesis, 2012. http://hdl.handle.net/1957/33727.
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The study of physical activity is important in improving people���s health as it can help people understand the relationship between physical activity and health. Accelerometers, due to its small size, low cost, convenience and its ability to provide objective information about the frequency, intensity, and duration of physical activity, has become the method of choice in measuring physical activity. Machine learning algorithms based on the featurized representation of accelerometer data have become the most widely used approaches in physical activity prediction. To improve the classification accuracy, this thesis first explored the impact of the choice of data (raw vs processed) as well as the choice of features on the performance of various classifiers. The empirical results showed that the machine learning algorithms with strong regularization capabilities always performed better if provided with the most comprehensive feature set extracted from raw accelerometer signal.
Based on the hypothesis that for some time series, the most discriminative information could be found at subwindows of various sizes, the Subwindow Ensemble Model (SWEM) was proposed. The SWEM was designed for the accelerometer-based physical activity data, and classified the time series based on the features extracted from subwindows. It was evaluated on six time series datasets. Three of them were accelerometer-based physical activity data, which the SWEM was designed for, and the rest were different types of time series data chosen from other domains. The empirical results indicated a strong advantage of the SWEM over baseline models on the accelerometerbased physical activity data. Further analysis confirmed the hypothesis that the most discriminative features could be extracted from subwindows of different sizes, and they were effectively used by the SWEM.Graduation date: 2013
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Long, Li. "Multi-Axis Fiber Bragg Grating Accelerometer". Thesis, 2010. http://hdl.handle.net/10222/12844.
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This thesis mainly focuses on sensor nodes design. A small two-axis and three-axis accelerometer using optic fiber with FBG written in the core as sensing element were originally designed due to the advantages of FBG mentioned above. The proposed design has a concentrated mass sitting in the middle of a rigid frame, and a glass fiber with a FBG written in the fiber core as a stiff spring is connected between each side of the frame and the mass. The two accelerometers can decouple the ground motion along different axes, resulting in virtually zero cross-sensitivity, which exceeds currently available seismometers. The accelerometer or seismometer has a working bandwidth below the structure’s natural frequency and linearly responds to ground movement. COMSOL Multiphysics by using Finite Element Method (FEM) was used to analyze and simulate the two devices.
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Lin, Chia-Wei, i 林佳暐. "CMOS MEMS Accelerometer With Variable Inductors". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/9qg5ea.
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碩士國立交通大學
電控工程研究所
103
In this thesis, an inductive sensing accelerometer was fabricated by CMOS MEMS process. This accelerometer use this spring as the oscillator inductors and MIM capacitors with the formation of an LC oscillator. The inductance value is changed due to the spring mass displacement and force causing by external acceleration. With changing in inductance value, LC oscillator frequency will also change. The change in the oscillator frequency will be proportional to the acceleration. It is capable for detecting acceleration by detecting different output frequencies. A 4/1000 change for inductance value is expected under 1g acceleration corresponding to oscillator frequency change of 3.3MHz. In this thesis, two device were designed and fabricated. Sample 1 was fabricated by 1P6M 0.18um process, and Sample 2 was 1P5M 0.18um process. Due to limited time and maintenance of facilities, post processes were not finished for Sample 2. Only part of the measurement for circuit have been done for Sample 2. For Sample 2, the circuit was working and an oscillator frequency of 2.7GHz was measured. The mixer output of Sample 2 was 33MHz. The mechanical properties measurement on Sample 1 has been done, the mechanical resonance frequency of 2.4kHz was measured. However, the circuit for Sample 1 was not working. A re-simulation for Sample 1 in later chapters has been done for discussing the failed reason.
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Charng, Jie-Yann, i 常嘉彥. "Analysis on Performance of Piezoelectric Accelerometer". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/77342756508756970797.
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碩士國立成功大學
機械工程研究所
84
Consider a piezoelectric beam. Based on the piezoelectricity with consideration for the coupling between the strain field and the electric field, a finite element formulation is developed. This study uses this code to analyze the response of the structure subjected to boundary vibration and the sensor electrical outputs as well as to determine the boundary condition from output voltage. Besides,this study also analyze performance limitations of the accelerometers as well as to determine the design parameter from some performance limitation.
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Li, Kun-Hong, i 李坤鴻. "Study on Accelerometer based Motion Classification". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/86891260402190392146.
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碩士國立臺灣科技大學
電機工程系
98
In this thesis, we reported our study of using a Wii Remote to capture the acceleration trajectories of motions, where those motions are considered as gestures for recognition. The aim of this study is to investigate the use of a Wii Remote in capturing motions made by a user so that those motions can be recognized to define some control commands for control electronic devices. A direct approach of motion classification with the use of some similarity measure used in Functional Artificial Neural Networks (FANN) will be proposed first. The second issue considered in our study is the use of the functional mapping characteristic of FANN for the motion classification problem. The original functions may not be easy to handle and then if the original function can be mapped by FANN to another functions which is easy to handle, the system may have more accurate classification for motions. Since two dimensional trajectories are considered in our experiments, a way of combining those two similarity measures is proposed. This measure fusion approach is based on the fuzzy concept and Gaussian functions are used to characterize the fuzzy membership functions. Our experiments show that the recognition rate of the proposed motion classification is about 96%. The use of FANN seems not helpful. A more subtle study is needed for this issue.