Дисертації з теми "High resolution displacement sensor"

L’objectif de la thèse est de réaliser un système de convoyage flexible permettant de déplacer des micro-objets. Ce système pourra être amené à être intégré dans une micro-usine ce qui nécessite une forte reconfigurabilité et une faible consommation d’énergie. Ces deux critères ont donc été considérés lors de la conception du système de convoyage. Ce dernier est basé sur un actionneur planaire électromagnétique, développé au sein du laboratoire Roberval, et sur une surface intelligente composée de 5 × 5 cellules élémentaires permettant chacune de déplacer la partie mobile dans les deux directions du plan et des rotations autour de l'axe perpendiculaire au plan. Un modèle analytique de l’actionneur a été développé afin de calculer les efforts électromagnétiques ainsi que le déplacement de la partie mobile. Ce modèle a été utilisé lors de la phase de conception du système de convoyage. Un prototype expérimental a ensuite été fabriqué et testé ce qui a permis de valider le principe de fonctionnement proposé. Des tests expérimentaux ont montré la possibilité de réaliser des déplacements de grande étendue dans les deux directions du plan. De multiples tests expérimentaux (pilotage en boucle ouverte, caractérisation des performances telles que rectitude de déplacement, répétabilité de positionnement, charge déplaçable, …) a été réalisée afin de qualifier les performances du système de convoyage. Les points sur la réalisation : - Une modélisation statique sous RADIA a été développée afin de concevoir la surface intelligente notamment la zone de transition entre deux cellules voisines. Une modélisation dynamique réalisée sous MATLAB a permis de simuler le comportement d’un moteur en boucle ouverte et en boucle fermée. - Un prototype de surface intelligente, composé d’un circuit imprimé multicouches (4 couches) de dimensions 130 mm x 130 mm, a été conçu sous EAGLE software. L’influence de la distance entre les deux premières couches a été étudiée à l’aide des modèles développés afin d'assurer un déplacement uniforme dans les deux directions. - Un test expérimental avec LABVIEW interface d'une cellule élémentaire de la surface intelligente avec une partie mobile composée de deux moteurs magnétiques orthogonaux a été réalisé et a permis de valider le fonctionnement du système de convoyage dans les deux directions du plan. - Une autre série de tests avec LABVIEW interface a été réalisée afin de valider expérimentalement le déplacement de la partie mobile avec la surface intelligente au niveau des zones de transition entre les cellules élémentaires. Ces tests expérimentaux ont montré des déplacements de grande étendue dans les deux directions du plan et de rotation autour de l'axe perpendiculaire au plan. Des déplacements de grande étendue et des rotations de la partie mobile ont été mesurés à l’aide d’une méthode de traitement d'image réalisée sous MATLAB. - Parallèlement, on a étudié un capteur à déplacement optique à haute résolution qui peut être intégré dans le convoyeur. Un algorithme robuste pour le traitement du signal de capteur à fibres optiques à haute résolution pour mesurer de déplacement est développé. Dans cet algorithme, la position optimale de la partie mobile est déterminée pour obtenir un basculement sans arrêt entre les sondes et l'algorithme est implémenté sous MATLAB et validée par la mise en œuvre des signaux expérimentaux. Ces travaux de thèse ont été publiés dans une revue internationale (Computers in Industry (COMIND)) et présentés dans des congrès internationaux (IEEE Sensors, REM Mechatronics, AIM, IWMF) pendant les années 2011 à 2016
The aim of the thesis is to provide a flexible conveyor system for moving micro-objects. The system may need to be integrated into a micro-factory which requires high reconfigurability and low power consumption. These two criteria have been considered in the design of the conveyor system. The conveyor is based on a planar electromagnetic actuator developed in the Laboratoire Roberval of the UTC, and on smart surface composed of 5 x 5 unit cells; each ceii moves th movable part in the two directions of the plane. An analytical model of the actuator has been developed in order to calculate the electromagnetic forces and the displacement of the mobile part. This modei has been used during the design phase of the conveying system. An experimental prototype is then manufactured and tested which has validated the proposed principle of operation. Experimental tests have shown the ability to perform wide area displacement in both directions of the plane. Numerous experimental tests (control in open loop and closed loop performance characterization as straightness of movement, position repeatability, coupled- decoupled analysis...) have been done to qualify the performance of the conveyor system. Experiments for rotations about the axis perpendicular to the olane have also been performed successfully. Work synthesis: - Static modeling under RADIA was developed in order to design the conveyor surface especially for the transitio zone between two neighboring cells. A dynamic modeling under MATLAB allowed to simulate the behavior of single axis motor in open loop and closed loop control. - A conveyor surface prototype, consisting of a multilayer printed circuit board (4 layers) of dimensions 130 mm x 130 mm, was designed under EAGLE software. The influence of the distance between the first two layers was studied using the developed models to ensure uniform displacement in both the directions. - The experimental tests (with LABVIEW interface) of an elementary cell of the intelligent surface with a moving part composed of two orthogonal magnetic motors has been carried out that allowed to validate the operation of the conveying system in both directions of the plane. - Another series of tests with LABVIEW interface were carried out in order to validate experimentally the displacement of the mobile part with the smart surface at the transition zones between the elementary cells. - These experimental tests showed displacements of great extent in the two directions of the plane and of rotation about the axis perpendicular to the plane. - Long displacements and rotations of the moving part were measured using image processing algorithm developed in MATLAB. - At the same time, a high resolution fiber optic displacement sensor was studied that can be integrated into the conveyor surface locally for the precise positioning. A robust signal processing algorithm for high resolution displacement measurement was developed. In this algorithm, - The optimum position of the movable part is determined in order to obtain a continuous switching betwee the two fiber optic probes ; - The usable parts of the signals obtained from two probes were then filtered to measure the displacement using interpolation method ; The algorithm is implemented under MATLAB and validated by the implementation of the experimental signals. The work have been published in an international journal (Computers in Industry (COMIND)) and presented at international congresses (IEEE Sensors, REM Mechatronics, AIM, IWMF) during the years 2011 to 2016

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.
Includes bibliographical references (leaves 125-126).
by Daniel Rea McMahill.
M.S.

As specialized materials are developed for various applications, it becomes desirable to test them under adverse conditions, such as at elevated temperatures and in harsh environments. It is increasingly important that sensors be developed to meet the growing needs of research and industry. The ability of sapphire to withstand elevated temperatures and many chemically harsh environments has long been recognized. However, currently available sapphire fiber possesses poor optical quality and is not available with a cladding. It has found use in a variety of temperature sensors, but the investigation of sapphire-based strain and displacement sensors has been limited.

The primary development of a white-light Michelson interferometer that utilizes a sapphire fiber sensing head is presented in this thesis. Development includes efforts to combat the poor optical quality of the sapphire fiber, minimize polarization mode fading, and preferentially excite the fundamental mode of the sapphire fiber. This thesis demonstrates the feasibility of fabricating a Michelson white-light interferometer capable of measuring displacements in environments ranging from room temperature to 800 degrees Celsius. The sensor developed in this work is capable of measuring displacements exceeding 6.4 millimeters at room temperature, and exceeding 1 millimeter at 800 degrees Celsius.

This thesis also presents the application of this sensor to the alignment of a sapphire-fiber based Fabry-Perot sensor. This technique allows the Fabry-Perot sensor to be aligned so that usable fringes are always obtained. Alignment of the sapphire-fiber based Fabry-Perot sensors has been considered prohibitively difficult.
Master of Science

The aim of this research is to investigate a novel Multiple-Input-Multiple-Output (MIMO) sensor system for automotive applications. Compared to traditional phased arrays, a MIMO array can achieve the same fine angular resolution, but with a drastically less amount of sensor elements. For example, a MIMO array of 10 elements can deliver the same resolution as a phased array of 25 elements. The other highlight of this technology is that it can operate at short ranges, which is physically impossible with a phased array. Therefore, a MIMO system can potentially provide very high angular resolutions at short ranges. These properties make such a system attractive for a number of automotive applications, including parking aids, short-range cruise control, speed-over-ground estimation, pedestrian detection etc. Research started with the verification of application of conventional MIMO techniques for radar context. MIMO techniques were tested with the existing RF equipment in laboratory environment. Beamforming capabilities were verified, range and angular resolutions were compared to equivalent phased arrays and multiple-target resolving capabilities were confirmed. Nearfield focusing algorithms for MIMO arrays were developed and verified via experiments in the anechoic chamber with the same equipment. A technology demonstrator based on ultrasonic equipment was built and then tested in an anechoic chamber and the findings were compared to computed performance parameters. Further performance optimisations via aperiodic MIMO configurations were explored via use of heuristic optimisation algorithms. An optimised configuration then was tested in anechoic chamber and its performance was confirmed in experimentally. Finally using radio equipment again, an initial study on MTI applications was done. Platform motion compensation methods were developed and tested in order to make up for vehicular motion and to compensate for its possible effects. Both stationary platforms and a moving platform was used to experimentally confirm the MTI capabilities on both in an indoor setup and an outdoor setup.

This dissertation presents the design and development of a high precision driver for an eddy current displacement sensor. The project was initiated to supplement the development of a low-cost PCB eddy current displacement sensor for active magnetic bearings (AMBs). The sensor driver will be implemented in AMB systems that will be used in various high-speed applications. The sensor driver is required to drive an eddy current PCB sensor, condition the output signals from the sensor, and send the conditioned position signals to an embedded digital controller. Circuit board design and development therefore constitute the main focus of this project. Research on the defining concepts of the project was imperative in gaining the necessary understanding of the project. AMB systems and the sensors used in these systems were investigated first. The eddycurrent type sensor used in this project, as well as the PCB sensor technology used were also researched. As analogue design constituted a main aspect of this project, the concepts of signal conditioning and sensor characteristics had to be comprehended. The sensor driver consists of several sub-systems, including a sensor excitation circuit to drive the sensor, a signal conditioning circuit to condition the output signals of the sensor, and a digital processing circuit for further processing of the position signals. A conceptual design was performed for each of these sub-systems, followed by a detail design, in which the conceptual designs of the sub-systems were realized. All the sub-systems were then integrated, and lastly evaluated. The evaluation of the sensor driver system included verification and validation of the system. The sensor driver design was verified, while the final sensor driver board was validated with regards to its specifications. Additional circuit characteristics such as signal-to-noise-ratio, sensitivity and resolution were also determined in order to characterize the sensor driver system. The overall outcome of the sensor driver project was successful, with all the characteristics of the sensor adhering to the requirements. It was determined that the sensor driver has a signal to noise ratio of 54 dB, a linearity of 9 %, a sensitivity of 26 .4 V/mm, and a resolution of 792.5 nm. Recommendations are made with regards to the sensor cables, heat distribution, and the low-pass filter on the field programmable gate array (FPGA). Future work will mainly focus on implementation of the sensor driver on a test bench and implementation of the linearization algorithm. Additional future work includes a study on EMC effects on the system and especially the cables, and further firmware enhancements of the sensor driver. These include input signal testing and temperature compensation. An investigation on the required excitation current for optimal sensor operation should also be done.
Thesis (M.Ing. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2010

Being able to predict the evolution of plastic deformation at the microstructural scale is of paramount importance in the engineering of materials for advanced applications. However, this is not straightforward because of the multiscale nature of deformation heterogeneity, both in space and time . The present thesis combines four related studies in a coherent work, which is aimed to develop experimental methods for studying crystal plasticity at the micro and mesoscale. A novel methodology for gold remodelling is initially proposed and used to apply high-density speckle patterns on the surface of stainless steel specimens. The unique proprieties of the speckle pattern enabled plastic deformation mapping with submicron resolution using digital image correlation (HDIC). It was therefore possible to study the concomitant evolution of microbands and transgranular deformation bands in such alloy. High-resolution deformation mapping also enabled comparison with high-resolution electron backscatter diffraction (EBSD) observations. The only partial correspondence of results proved the limits of EBSD in characterizing plastic deformation. The cause of such limitation is later identified in the reduced sensitivity to lattice slip of the EBSD technique. Hence, a novel method of HDIC data analysis is proposed to separate the contributions of lattice slip and lattice rotation from the deformation mapping. The method is adopted to characterize plasticity in austenitic stainless steel and at the plastic deformation zone (PDZ) around a silicon particle embedded in a softer aluminum matrix. Results show that the proposed experimental methodology has the unique capability of providing a complete description of the micro and mesoscale mechanics of crystal plasticity. HDIC therefore emerges as a key technique in the development of accurate physical-based multiscale crystal plasticity models.

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California
The U.S. Army Research Laboratory (ARL) is developing an onboard instrument and telemetry system to obtain measurements of the 30mm MK310 projectile's in-flight dynamics. The small size, high launch acceleration, and extremely high rates of this projectile create many design challenges. Particularly challenging is the high spin rate which can reach 1400 Hz at launch. The bandwidth required to continuously transmit solar data using the current method for such a rate would leave no room for data from other sensors. To solve this problem, a data compression scheme is implemented that retains the resolution of the solar sensor data while providing room in the telemetry frame for other measurements.

Optical fibre sensors have offered such unrivalled distributed sensing features that they continue to be successfully exploited in various industries for performing continuous measurements of the physical parameters, such as, temperature and strain. However, there arise certain conditions in engineering or materials manufacturing and characterisation environments, when the user seeks to extract the knowledge about a single physical parameter only, say strain, whilst the environment is also subject to temperature. This thesis explores techniques to offer solutions under such conditions by developing a high spatial resolution temperature compensated distributed strain sensor. The preliminary exploration involved exploiting the high spatial resolution Brillouin frequency based Brillouin optical correlation domain analysis technique in combination with the anti Stokes Raman intensity based optical time domain reflectometry technique. This work resulted in achieving a temperature compensated strain resolution of 46με with a spatial resolution of 24cms over a sensing length of 135m. Tackling the impact of modest pump depletion effects on the Raman backscattered signal, a beneficial normalisation protocol was identified. During discussions the possible limitation imposed by the weaker backscattered Raman signal towards achieving any better results on the strain and spatial resolution values, seemed to emerge. In order to enhance the performance of the sensor, anti Stokes Brillouin, which is a stronger back scattered signal, was exploited for the time domain reflectometry measurements. This resulted in 22με of temperature compensated strain resolution with a spatial resolution capability of 10cms. Although the combined performance of the Brillouin frequency in combination with Brillouin intensity proved better than the performance of the Brillouin frequency in combination with Raman intensity, but since the electronic detection system was changed together with pulse widths between the two techniques that it was unclear as to which combinatory technique was best suited for designing the sensor. It is with this view that a theoretical analysis on the performance of the R-OTDR and B-OTDR was carried under similar sensor parameters. B-OTDR is identified as a better technique compared to the R-OTDR towards providing high spatial resolution temperature compensation feature to the Brillouin frequency based distributed strain measurements. The exploration also gave an opportunity to experimentally study for the first time the impact of simultaneously varying temperature and strain on the four Brillouin coefficients. This study proved useful in identifying the corrections to the Brillouin coefficients in order to estimate the true value of strain and temperature in a temperature controlled variable strain environment. The thesis culminates with a summary of work, discussing the thresholds of various non linear effects together with means to improve the performance of the sensor. With the view of enhancing the sensor applicability, schemes of loss compensation are also discussed. In conclusion work for the future is highlighted.

An efficient and simple method has been developed to improve quality and accuracy of satellite-based VIS/IR images through cloud-top relief spatial displacements adjustment. The products of this algorithm, including cloud-top temperatures and heights, atmospheric temperature profiles for cloudy sky, and displacement-adjusted cloud images, can be useful for weather/climate and atmospheric studies, particularly for high-resolution hydrologic applications such as developing IR satellite-based rainfall estimates, which are urgently needed by mesoscale atmospheric modeling and studies, severe weather monitoring, and heavy precipitation and flash flood forecasting. Cloud-top height and displacement are estimated by applying stereoscopic analysis to a pair of corresponding scan-synchronous infrared images from geostationary satellites (GOES-east and GOES-west). A piecewise linear approximation relationship between cloud-top height and temperature, with a few (6 and 8) parameters is developed to simplify and speed-up the retrieval process. Optimal parameters are estimated using the Shuffled Complex Evolution (SCE-UA) algorithm to minimize the discrepancies between the brightness temperatures of the same location as registered by two satellites. The combination of the linear approximation and the fast optimization algorithm simplifies stereoscopic analysis and allows for its implementation on standard desktop computers. When compared to the standard isotherm matching approaches the proposed method yields higher correlation between simultaneous GOES-8 and GOES-9 images after parallax adjustment. The validity of the linear approximation was also tested against temperature profiles obtained from ground sounding measurements of the TRMM-TEFLUN experiments. This comparison demonstrated good fit between the optimized relationship and atmospheric sounding profile. The accuracy of cloud pixel geo-location was demonstrated through a spatial comparison between correlation of ground-based radar rainfall rate and corresponding both adjusted and original satellite IR images. Higher correlation was represented using displacement-adjusted IR images from both geostationary satellites (GOES) with high altitudes and low altitude satellite (TRMM). Higher correlation and lower RMSE between ground-based NEXRAD observations and estimated rainfall rates from spatial adjusted IR images, using an artificial neural networks algorithm (PERSIANN), present the rainfall retrieval improvement. The ability to differentiate ground surface particularly snow-covered areas from clouds in near-real-time is another useful application of estimated cloud-top height.

Conductive nanocomposites are finding many uses as multi-functional materials. One recent development involves the creation of high displacement strain gauges, which have potential applications in a variety of engineering roles. The piezoresistive nature of the gauges makes possible their strain sensing capability. The intent of this research is to show that specific High Displacement Strain Gauges can successfully be used in one human-machine interface application that will demonstrate their potential for a range of other human-machine interface applications. This will be shown in the development of these sensors to accomplish hand pose determination. The flexible and inexpensive gauges are attached to several locations on a glove. It is then shown that by linking this glove with software, the position of the hand can be interpreted into the letters of the American Sign Language alphabet. This use of this nanocomposite sensor establishes the potential for future applications. Issues such as accuracy of response, cyclability, recalibration and reliability are discussed. A design of experiments is accomplished in order to evaluate the effects of modification of the gauges in order to overcome these issues. This work develops the potential of these sensors for use in human-machine interface applications such as computer games, remote controls, robotics, prosthetics and virtual reality applications.

A systematic and detailed design, building and testing of a high-sensitivity real-time magnetovision imaging system for non-destructive testing (NDT) was the purpose of the research presented here. The magnetic imaging systems developed were all based on an ultra-high sensitivity Quantum Well Hall Effect (QWHE) sensors, denoted as the P2A, which is based on GaAs-InGaAs-AlGaAs 2DEG heterostructures. The research progressed from 0D (single sensor) to 1D (linear array) to 2D (two dimensional arrays) testing modalities. Firstly, the measurement of thermal and shot noises, drift, detection limit, and dynamic offset cancellation of the QWHE sensor were studied in detail to set the framework and limitations of the fundamental QWHE sensors before their eventual use in the imaging systems developed subsequently. The results indicate that the measured data agrees well with calculations for thermal and shot noise when the input bias current is < 3 mA. The measured drift voltages of various QWHE sensors (P2A and P3A) are less than 200 µV when the sensor bias voltage is less than or equal to 2 V. A 4-direction dynamic offset cancellation technique was developed and the results show that the offset equivalent magnetic field of the QWHE sensors can be reduced from ~ 1mT to readings equal to the Earth magnetic field (~ 50 µT). Secondly, a flexible 16 × 1 array and a 32 × 2 staggered array magnetic-field scanners were designed, built, and tested. The QWHE magnetometer had a field strength resolution of 100 nT, and a measurement dynamic range of 138 dB. The flexible 16 × 1 magnetic field scanner can be used to test uneven and/or curved surfaces. This gives the flexible magnetic field scanner better inspection capabilities in both welding hump and circular pipe samples. By the staggered arrangement of two sensor arrays, a 15.4 point per inch horizontal spatial resolution can be achieved for the staggered 32 × 2 magnetic field scanner. Both direct and alternating magnetic flux leakage (DC and AC MFL) tests with the QWHE magnetometer were accomplished to obtain graphical 2-dimensional magnetic field distributions. Both the shape and the location of defects can be identified. The results show that the sensor has high sensitivity and linearity in a wide frequency range which makes it an optimum choice for AC-MFL testing and both ferromagnetic and non-ferromagnetic materials can be investigated. Thirdly, real-time 8 × 8 and 16  16 QWHE array magnetic-field cameras were designed, built, and tested. These prototypes can measure static magnetic field strengths in a 2-dimensional plane. Different shapes of magnets and magnetic field polarities can all be identified by the 8 × 8 magnetic field camera. The camera has a resolution of 3.05 mT, and a dynamic range of 66 dB (the minimum and maximum fields measurable are 3.05 mT and 6.25 mT) and a real time magnetic field measurement rate of 13 frames per second (FPS). By contrast the1616 array magnetic field camera has an improved sampling rate of 600 frame per second and with the use of an interpolation technique, a spatial resolution of 40.6 point per inch can be achieved. The minimum and maximum detectable magnetic field for this magnetic field camera are 1.8 µT and 29.5 mT respectively leading to a record dynamic range of 84 dB for high quality imaging. Finally, a novel, hand held, magnetovision system based on the real-time 16 × 16 QWHE array magnetic-field camera was developed for improved DC and AC electromagnetic NDT testing. The system uses a new super heterodyne technique for data acquisition using the QWHE sensor as a multiplier. This is the first report of such a technique in Hall effect magnetometry. The experimental results of five case studies demonstrate that the defects location and shape can be successfully measured with MFL in DC and AC magnetic field configurations including depth profiling. The major advantages of this real-time magnetic-field camera are: (1) its ease to use as a MFL testing equipment in both DC and AC NDT testing, (2) its ability to provide 2D graphical images similar to Magnetic Particle Inspection (MPI) but without its inherent health and safety drawbacks, (3) its capability to test both ferromagnetic and non-ferromagnetic materials for deep defects below the surface using low frequency alternating magnetic fields, and (4) its ability to identify materials (metals) by alternating external magnetic field illuminations, which has considerable potential in several applications such as security checking and labelling, magnetic markers for analysis, bio-imaging detection, and medical treatments amongst others.

This thesis reports on two graphene-based structures that have been proposed and fabricated as possible prototypes for high-spatial-resolution Hall sensors with potential application in research on high-density magnetic recording technology such as bit patterned magnetic recording (BPMR) and other areas where the measurement of highly inhomogeneous fields is required. There is a direct graphene-metal contact in the first structure, which is named as TYPE I in this thesis, so that the anomalous Hall effect (AHE) in the ferromagnetic islands deposited on the graphene could be detected. Meanwhile, the graphene and the metal are isolated by an h-BN layer in the second structure which is named as TYPE II, so that only the stray field from the islands can be detected using the ordinary Hall effect (OHE).The transport measurements performed on TYPE I devices revealed there is no AHE or stray field signal detectable, and their Hall resistance relations are non-linear and do not pass through the origin point. A finite element simulation comparing the resistance of the empty graphene cross and the island-occupied cross indicates that the current in the graphene may not redistribute through the metallic islands due to interface current blocking, resulting in the non-appearance of the expected AHE signal. Moreover, an analysis on the data of the longitudinal magnetoresistance (MR) reveals that a two-fluid model and effective medium theory (EMT) model might be the major graphene MR mechanisms in the regime away from and near to the charge neutrality point (CNP) respectively. As a combined result of the above findings, a joint MR-Hall effect model under the condition of the presence of a pre-existing transverse offset current, is proposed to explain the unusual behaviour of the Hall measurement data of the TYPE I devices. The model gives qualitatively correct fitting for all longitudinal and transverse transport data of TYPE I devices. In addition, the nature of the graphene/metal contact is considered as the reason responsible for the non-appearance of the expected AHE and stray field signal, although further experimental work is needed, and suggested in the thesis, to clarify this issue. On the other hand, the TYPE II devices have shown their potential to be developed as a Hall sensor being able to detect a sub-micron magnetic island in the future, but there is still a large space for the performance of the devices to be improved. At the end of the thesis, future experimental work, which could lead to the eventual development of a high-sensitivity high-spatial-resolution Hall sensor on the basis of TYPE I and TYPE II structures, are suggested and described.

Les systèmes neuromusculaires et musculo-squelettique sont considérés comme un système de systèmes complexe. En effet, le mouvement du corps humain est contrôlé par le système nerveux central par l'activation des cellules musculaires squelettiques. L'activation du muscle produit deux phénomènes différents : mécanique et électrique. Ces deux activités possèdent des propriétés différentes, mais l'activité mécanique ne peut avoir lieu sans l'activité électrique et réciproquement. L'activité mécanique de la contraction du muscle squelettique est responsable du mouvement. Le mouvement étant primordial pour la vie humaine, il est crucial de comprendre son fonctionnement et sa génération qui pourront aider à détecter des déficiences dans les systèmes neuromusculaire et musculo-squelettique. Ce mouvement est décrit par les forces musculaires et les moments agissant sur une articulation particulière. En conséquence, les systèmes neuromusculaires et musculo-squelettique peuvent être évalués avec le diagnostic et le management des maladies neurologiques et orthopédiques à travers l'estimation de la force. Néanmoins, la force produite par un seul muscle ne peut être mesurée que par une technique très invasive. C'est pour cela, que l'estimation de cette force reste l'un des grands challenges de la biomécanique. De plus, comme dit précédemment, l'activation musculaire possède aussi une réponse électrique qui est corrélée à la réponse mécanique. Cette résultante électrique est appelée l'électromyogramme (EMG) et peut être mesurée d'une façon non invasive à l'aide d'électrodes de surface. L'EMG est la somme des trains de potentiel d'action d'unité motrice qui sont responsable de la contraction musculaire et de la génération du mouvement. Ce signal électrique peut être mesuré par des électrodes à la surface de la peau et est appelé I'EMG de surface {sEMG). Pour un muscle unique, en supposant que la relation entre l'amplitude du sEMG et la force est monotone, plusieurs études ont essayé d'estimer cette force en développant des modèles actionnés par ce signal. Toutefois, ces modèles contiennent plusieurs limites à cause des hypothèses irréalistes par rapport à l'activation neurale. Dans cette thèse, nous proposons un nouveau modèle de relation sEMG/force en intégrant ce qu'on appelle le sEMG haute définition (HD-sEMG), qui est une nouvelle technique d'enregistrement des signaux sEMG ayant démontré une meilleure estimation de la force en surmontant le problème de la position de l'électrode sur le muscle. Ce modèle de relation sEMG/force sera développé dans un contexte sans fatigue pour des contractions isométriques, isotoniques et anisotoniques du Biceps Brachii (BB) lors une flexion isométrique de l'articulation du coude à 90°
The neuromuscular and musculoskeletal systems are complex System of Systems (SoS) that perfectly interact to provide motion. This interaction is illustrated by the muscular force, generated by muscle activation driven by the Central Nervous System (CNS) which pilots joint motion. The knowledge of the force level is highly important in biomechanical and clinical applications. However, the recording of the force produced by a unique muscle is impossible using noninvasive procedures. Therefore, it is necessary to develop a way to estimate it. The muscle activation also generates another electric phenomenon, measured at the skin using electrodes, namely the surface electromyogram (sEMG). ln the biomechanics literature, several models of the sEMG/force relationship are provided. They are principally used to command musculoskeletal models. However, these models suffer from several important limitations such lacks of physiological realism, personalization, and representability when using single sEMG channel input. ln this work, we propose to construct a model of the sEMG/force relationship for the Biceps Brachii (BB) based on the data analysis of a High Density sEMG (HD-sEMG) sensor network. For this purpose, we first have to prepare the data for the processing stage by denoising the sEMG signals and removing the parasite signals. Therefore, we propose a HD-sEMG denoising procedure based on Canonical Correlation Analysis (CCA) that removes two types of noise that degrade the sEMG signals and a source separation method that combines CCA and image segmentation in order to separate the electrical activities of the BB and the Brachialis (BR). Second, we have to extract the information from an 8 X 8 HD-sEMG electrode grid in order to form the input of the sEMG/force model Thusly, we investigated different parameters that describe muscle activation and can affect the relationship shape then we applied data fusion through an image segmentation algorithm. Finally, we proposed a new HDsEMG/force relationship, using simulated data from a realistic HD-sEMG generation model of the BB and a Twitch based model to estimate a specific force profile corresponding to a specific sEMG sensor network and muscle configuration. Then, we tested this new relationship in force estimation using both machine learning and analytical approaches. This study is motivated by the impossibility of obtaining the intrinsic force from one muscle in experimentation

Chatter is an unstable forced vibration of the cutting tool during machining processes that can limit the productivity of high-speed machining. Chatter increases tool and machine wear rates, reduces tolerances, degrades surface finish, and can result in tool breakage. For these reasons, its avoidance is critical. Researchers at N.C. State University are focusing on the development of technologies to detect and avoid this dynamic instability. The primary objective of this project is to develop accurate, high bandwidth, low cost capacitive displacement sensors for use with a prototype electromechanically actuated chatter prediction device. These application-specific sensors are required to have at least 1.0 m resolution, 1.0 kHz bandwidth, and linearity over the desired measurement ranges. These sensors must output analog DC voltages proportional to the vertical and horizontal displacements of a specifically engineered machine tool. A simulation-based design process is utilized to optimize the mechanical and electrical aspects of these capacitive probes, the electrical circuits, and the mechanical mounting hardware. Performance and stability are simulated using MATLAB® and SPICE® modeling software and are validated experimentally using static and dynamic test rigs.

Thesis (Ph.D.)--University of Mississippi, 2008.
Typescript. Vita. "December 2008." Committee chair: Dr. Greg Easson Includes bibliographical references (leaves 126-134). Also available online via ProQuest to authorized users.

Aquesta tesi doctoral explora mètodes per augmentar tant l'eficiència energètica com la resolució de convertidors analògic-digital (ADCs) Delta-Sigma de condensadors commutats mitjançant innovadors circuits CMOS de baix consum. En aquest sentit, s'ha prioritzat un alt rendiment, fiabilitat i baixos costos de fabricació dels circuits, així com un flux de disseny simple per ser reutilitzat per la comunitat científica. S'ha escollit l'arquitectura Delta-Sigma per la seva simplicitat i la tolerància a les imperfeccions dels seus blocs bàsics. La recerca de circuits presentada utilitza tècniques de condensadors commutats per aconseguir un aparellament adequat entre els dispositius i per tenir dependència només de la fluctuació del rellotge extern. Les tècniques de disseny de circuits analògics de baix corrent desenvolupades tenen com a objectiu l'eficiència energètica, aprofitant les regions d'inversió feble i moderada d'operació del transistor MOS. També s'investiguen nous amplificadors operacionals Classe AB com a elements actius, tractant d'utilitzar energia només durant les transicions dinàmiques, el que redueix el consum de potència a nivell de circuit. Els circuits no utilitzats durant un determinat període de temps es desactiven, reduint així el consum de potència a nivell de sistema i minimitzant el nombre de dispositius de commutació en el camí de senyal. S'ha millorat la fiabilitat dels circuits proposats evitant els elevadors de tensió o altres tècniques que poden incrementar els voltatges d'operació més enllà del d'alimentació nominal de la tecnologia CMOS utilitzada. A més, per incrementar el rendiment de producció dels ADCs resultants, s'ha enfocat la recerca de disseny sobre noves topologies de circuits amb una baixa sensibilitat a les variacions tant del procés de fabricació com de la temperatura. Un modulador Delta-Sigma de 96.6 dB de SNDR, 50 kHz d'ample de banda, 1.8 V i 7.9 mW per a ADCs s'ha implementat en una tecnologia estàndard CMOS de 0.18 µm basat en les novetats proposades. Els resultats de les mesures indiquen la millora de l'estat de l'art d'ADCs d'alta resolució sense elevadors de tensió del senyal de rellotge, calibratge o compensació digital, fet que beneficia una àmplia gamma d'aplicacions de sensors intel·ligents. Una altra contribució en el marc d'aquest treball de recerca és la millora dels amplificadors operacionals de Classe AB d'una sola etapa exclusivament MOS. Els amplificadors commutats de mirall variable desenvolupats, amb la seva remarcable eficiència de corrent i compensació intrínseca de freqüència juntament amb un fons d'escala i un guany de llaç obert grans, són adequats per a un ample ventall d'aplicacions de baix consum i d'alta precisió més enllà de l'àmbit
This PhD thesis explores methods to increase both the power efficiency and the resolution of switched-capacitor Delta-Sigma analog-to-digital converters (ADCs) by employing novel CMOS low-power circuits. A high circuit performance, reliability, low manufacturing costs and a simple design flow to be reused by the scientific community are prioritized. The Delta-Sigma architecture is chosen because of its simplicity and tolerance for its basic block imperfections. The presented circuit research makes use of switched-capacitor techniques to achieve an appropriate matching between the devices and to be dependent only on the external clock jitter. The developed low-current analog circuit techniques target power efficiency, taking advantage of the weak- and moderate-inversion regions of the MOS transistor operation. Novel Class-AB operational amplifiers are also investigated as active elements, trying to use energy only for dynamic transitions, thus reducing power consumption at the circuit level. The circuits unused during a certain period of time are switched off, thus reducing power consumption at the system level and minimizing the number of signal-path switching devices. The circuit reliability is improved by avoiding bootstrapping or other techniques which may increase the operation voltages beyond the nominal supply of the target CMOS technology. Furthermore, the design research also focuses on new circuit topologies with a low sensitivity to both process and temperature deviations in order to increase the yield of the resulting ADCs. A 96.6-dB-SNDR 50-kHz-BW 1.8-V 7.9-mW Delta-Sigma modulator for ADCs is implemented in a standard 0.18-µm CMOS technology based on the proposed novelties. The measurement results indicate the improvement of the state of the art of high-resolution ADCs without clock bootstrapping, calibration or digital compensation, benefiting a wide range of smart sensing applications. Another contribution made in the scope of this research work is the improvement of MOS-only single-stage Class-AB operational amplifiers. The developed switched variable-mirror amplifiers, with their remarkable current efficiency and intrinsic frequency compensation together with high full-scale value and open-loop gain, are suitable for low-power high-precision applications extending beyond the specific area of ADCs, such as digital-to-analog converters (DACs), filters or generators.

Over the last several decades, electricity consumption and generation have continually grown. Investment in the Transmission and Distribution (T&D) infrastructure has been minimal and it has become increasingly difficult and expensive to permit and build new power lines. At the same time, a growing increase in the penetration of renewable energy resources is causing an unprecedented level of dynamics on the grid. Consequently, the power grid is congested and under stress. To compound the situation, the utilities do not possess detailed information on the status and operating margins on their assets in order to use them optimally. The task of monitoring asset status and optimizing asset utilization for the electric power industry seems particularly challenging, given millions of assets and hundreds of thousands of miles of power lines distributed geographically over millions of square miles. The lack of situational awareness compromises system reliability, and raises the possibility of power outages and even cascading blackouts. To address this problem, a conceptual Power Line Sensor Network (PLSN) is proposed in this research. The main objective of this research is to develop a distributed PLSN to provide continuous on-line monitoring of the geographically dispersed power grid by using hundreds of thousands of low-cost, autonomous, smart, and communication-enabled Power Line Sensor (PLS) modules thus to improve the utilization and reliability of the existing power system. The proposed PLSN specifically targets the use of passive sensing techniques, focusing on monitoring the real-time dynamic capacity of a specific span of a power line under present weather conditions by using computational intelligence technologies. An ancillary function is to detect the presence of incipient failures along overhead power lines via monitoring and characterizing the electromagnetic fields around overhead conductors. This research integrates detailed modeling of the power lines and the physical manifestations of the parameters being sensed, with pattern recognition technologies. Key issues of this research also include design of a prototype PLS module with integrated sensing, power and communication functions, and validation of the Wireless Sensor Network (WSN) technology integrated to this proposed PLSN.

[EN] Different electronic interfaces have been proposed to measure major parameters for the characterization of quartz crystal microbalance (QCM) during the last two decades. The measurement of the adequate parameters of the sensor for a specific application is very important, since an error in this measure can lead to an error in the interpretation of the results. The requirements of the system of characterization depend on the application. In this thesis we propose two characterization systems for two types of applications that involve the majority of sensor applications: 1) Characterization of materials under variable damping conditions and 2) Detection of substances with high measurement resolution. The proposed systems seek to solve the problems detected in the systems currently in use. For applications in which the sensor damping varies during the experiment, we propose a system based on a new configuration of the technique of automatic capacitance compensation (ACC). This new configuration provides the measure of the series resonance frequency, the motional resistance and the parallel capacitance of the sensor. Moreover, it allows an easy calibration of the system that improves the precision in the measurement. We show the experimental results for 9 and 10 MHz crystals in fluid media, with different capacitances in parallel, showing the effectiveness in the capacitance compensation. The system presents some deviation in frequency with respect to the series resonance frequency, as measured with an impedance analyser. These deviations are due to the non-ideal, specific behaviour of some of the components of the circuit. A new circuit is proposed as a possible solution to this problem. For high-resolution applications we propose an integrated platform to characterize high-frequency acoustic sensors. The proposed system is based on a new concept in which the sensor is interrogated by means of a very stable, low-noise external source at a constant frequency, while the changes provoked by the charge in the phase of the sensor are monitored. The use of high-frequency sensors enhances the sensitivity of the measure, whereas the design characterization system reduces the noise in the measurement. The result is an improvement in the limit of detection (LOD). This way, we achieve one of the challenges in the acoustic high-frequency devices. The validation of the platform is performed by means of an immunosensor based in high fundamental frequency QCM crystals (HFF-QCM) for the detection of two pesticides: carbaryl and thiabendazole. The results obtained for carbaryl are compared to the results obtained by another high-frequency acoustic technology based in Love sensors, with the optical technique based in surface plasmonic resonance and with the gold standard technique Enzyme Linked Immunoassay (ELISA). The LOD obtained with the acoustic sensors HFF-QCM and Love is similar to the one obtained with ELISA and improves by one order of magnitude the LOD obtained with SPR. The conceptual ease of the proposed system, its low cost and the possibility of miniaturization of the quartz resonator, allows the characterization of multiple sensors integrated in an array configuration, which will allow in the future to achieve the challenge of multianalyte detection for applications of High-Throughput Screening (HTS).
[ES] Durante las dos últimas décadas se han propuesto diferentes interfaces electrónicos para medir los parámetros más importantes de caracterización de los cristales de microbalanza de cuarzo (QCM). La medida de los parámetros adecuados del sensor para una aplicación específica es muy importante, ya que un error en la medida de dichos parámetros puede resultar en un error en la interpretación de los resultados. Los requerimientos del sistema de caracterización dependen de la aplicación. En esta tesis se proponen dos sistemas de caracterización para dos ámbitos de aplicación que comprenden la mayoría de las aplicaciones con sensores QCM: 1) Caracterización de materiales bajo condiciones de amortiguamiento variable y 2) detección de sustancias con alta resolución de medida. Los sistemas propuestos tratan de resolver la problemática detectada en los ya existentes. Para aplicaciones en las que el amortiguamiento del sensor varía durante el experimento, se propone un sistema basado en una nueva configuración de la técnica de compensación automática de capacidad (ACC). La nueva configuración proporciona la medida de la frecuencia de resonancia serie, la resistencia dinámica y la capacidad paralelo del sensor. Además, permite una fácil calibración del sistema que mejora la precisión en la medida. Se presentan resultados experimentales para cristales de 9 y 10MHz en medios fluidos, con diferentes capacidades en paralelo, demostrando la efectividad de la compensación de capacidad. El sistema presenta alguna desviación en frecuencia con respecto a la frecuencia resonancia serie, medida con un analizador de impedancias. Estas desviaciones son explicadas convenientemente, debidas al comportamiento no ideal específico de algunoscomponentes del circuito. Una nueva propuesta de circuito se presenta como posible solución a este problema. Para aplicaciones de alta resolución se propone una plataforma integrada para caracterizar sensores acústicos de alta frecuencia. El sistema propuesto se basa en un nuevo concepto en el que el sensor es interrogado, mediante una fuente externa muy estable y de muy bajo ruido, a una frecuencia constante mientras se monitorizan los cambios producidos por la carga en la fase del sensor. El uso de sensores de alta frecuencia aumenta la sensibilidad de la medida, por otro lado, el sistema de caracterización diseñado reduce el ruido en la misma. El resultado es una mejora del límite de detección (LOD). Se consigue con ello uno de los retos pendientes en los dispositivos acústicos de alta frecuencia. La validación de la plataforma desarrollada se realiza con una aplicación de un inmunosensor basado en cristales QCM de alta frecuencia fundamental (HFF-QCM) para la detección de dos pesticidas: carbaryl y tiabendazol. Los resultados obtenidos para el Carbaryl se comparan con los obtenidos con otra tecnología acústica de alta frecuencia basada en sensores Love, con la técnica óptica basada resonancia superficial de plasmones (SPR) y con la técnica de referencia Enzyme Linked Immuno Assay (ELISA). El LOD obtenido con los sensores acústicos HFFQCM y Love es similar al obtenido con las técnicas ELISA y mejora en un orden de magnitud al obtenido con SPR. La sencillez conceptual del sistema propuesto junto con su bajo coste, así como la capacidad de miniaturización del resonador de cuarzo hace posible la caracterización de múltiples sensores integrados en una configuración en array, esto permitirá en un futuro alcanzar el reto de la detección multianalito para aplicaciones High-Throughput Screening (HTS).
[CAT] Durant les dues últimes dècades s'han proposat diferents interfases electrònics per a mesurar els paràmetres més importants de caracterització dels cristalls de microbalança de quars (QCM). La mesura dels paràmetres adequats del sensor per a una aplicació específica és molt important, perquè un error en la interpretació dels resultats pot resultar en un error en la interpretació dels resultats. Els requeriments del sistema de caracterització depenen de l'aplicació. En aquesta tesi, es proposen dos sistemes de caracterització per a dos àmbits d'aplicació que comprenen la majoria de les aplicacions amb sensors QCM: 1) Caracterització de materials sota condicions d'amortiment variable i 2) detecció de substàncies amb alta resolució de mesura. Els sistemes proposats tracten de resoldre la problemàtica detectada en els ja existents. Per a aplicacions en les quals l'amortiment del sensor varia durant l'experiment, es proposa un sistema basat en una nova configuració de la tècnica de compensació automàtica de capacitat (ACC). La nova configuració proporciona la mesura de la freqüència de ressonància sèrie, la resistència dinàmica i la capacitat paral¿lel del sensor. A més, permet un calibratge fàcil del sistema que millora la precisió de la mesura. Es presenten els resultats experimentals per a cristalls de 9 i 10 MHz en mitjans fluids, amb diferents capacitats en paral¿lel, demostrant l'efectivitat de la compensació de capacitat. El sistema presenta alguna desviació en freqüència respecte a la freqüència ressonància sèrie, mesurada amb un analitzador d'impedàncies. Aquestes desviacions són explicades convenientment, degudes al comportament no ideal específic d'alguns components del circuit. Una nova proposta de circuit es presenta com a possible solució a aquest problema. Per a aplicacions d'alta resolució es proposa una plataforma integrada per a caracteritzar sensors acústics d'alta freqüència. El sistema proposat es basa en un nou concepte en el qual el sensor és interrogat mitjançant una font externa molt estable i de molt baix soroll, a una freqüència constant mentre es monitoritzen els canvis produïts per la càrrega en la fase del sensor. L'ús de sensors d'alta freqüència augmenta la sensibilitat de la mesura, per altra banda, el sistema de caracterització dissenyat redueix el soroll en la mateixa. El resultat és una millora en el límit de detecció (LOD). S'aconsegueix amb això un dels reptes pendents en els dispositius acústics d'alta freqüència. La validació de la plataforma desenvolupada es realitza amb una aplicació d'un immunosensor basat en cristalls QCM d'alta freqüència fonamental (HFF-QCM) per a la detecció de dos pesticides: carbaryl i tiabendazol. Els resultats obtinguts per al carbaryl es comparen amb els obtinguts amb altra tecnologia acústica d'alta freqüència basada en sensors Love, amb la tècnica òptica basada en ressonància superficial de plasmons (SPR) i amb la tècnica de referència Enzyme Linked Immuno Assay (ELISA). El LOD obtingut amb els sensors acústics HFF-QCM i Love és similar al obtingut amb les tècniques ELISA i millora en un ordre de magnitud el obtingut amb SPR. La senzillesa conceptual del sistema proposat junt amb el seu baix cost, així com la capacitat de miniaturització del ressonador de quars fa possible la caracterització de múltiples sensors integrats en una configuració en array, el que permetrà en un futur assolir el repte de la detecció multianalit per a aplicacions High-Throughput Screening (HTS).
García Narbón, JV. (2016). Improved characterization systems for quartz crystal microbalance sensors: parallel capacitance compensation for variable damping conditions and integrated platform for high frequency sensors in high resolution applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63249
TESIS

The uniquely predictable and controllable binding mechanism of DNA strands has been exploited to construct a vast range of synthetic nanodevices, capable of autonomous motion and computation. This thesis proposes novel ideas for the control and observation of such devices. The first of these proposals hinges on introducing mismatched base pairs into toehold-mediated strand displacement – a fundamental primitive in most dynamic DNA devices and reaction networks. Previous findings that such mismatches can impede strand displacement are extended insofar as it is shown that this impediment is highly dependent on mismatch position. This discovery is examined in detail, both experimentally and through simulations created with a coarse-grained model of DNA. It is shown that this effect allows for kinetic control of strand displacement decoupled from reaction thermodynamics. The second proposal improves upon a previously presented strand displacement scheme, in which two strands perform displacement cooperatively. This scheme is extended to be cascadable, so that the output of one such reaction serves as input to the next. This scheme is implemented in reaction networks capable of performing fundamental calculations on directed graphs. The third proposal is exclusively concerned with a novel observation methodology. This method is based on single-molecule fluorescence microscopy, and uses quantum dots, a fluorescent type of semiconductor nanocrystal, as a label. These quantum dots display a set of characteristics particularly promising for single-molecule studies on the time- and length scales most commonly encountered in DNA nanotechnology. This method is shown to allow for highly precise measurements on static DNA devices. Preliminary data for the observation of a complex dynamic device is also presented.

This thesis focuses upon automatic target recognition (ATR) with radar sensors. Recent advancements in ATR have included the processing of target signatures from multiple, spatially-diverse perspectives. The advantage of multiple perspectives in target classification results from the angular sensitivity of reflected radar transmissions. By viewing the target at different angles, the classifier has a better opportunity to distinguish between target classes. This dissertation extends recent advances in multi-perspective target classification by: 1) leveraging bistatic target reflectivity signatures observed from multiple, spatially-diverse radar sensors; and, 2) employing a statistical distance measure to identify radar sensor locations yielding improved classification rates. The algorithms provided in this thesis use high resolution range (HRR) profiles – formed by each participating radar sensor – as input to a multi-sensor classification algorithm derived using the fundamentals of statistical signal processing. Improvements to target classification rates are demonstrated for multiple configurations of transmitter, receiver, and target locations. These improvements are shown to emanate from the multi-static characteristics of a target class’ range profile and not merely from non-coherent gain. The significance of dominant scatterer reflections is revealed in both classification performance and the “statistical distance” between target classes. Numerous simulations have been performed to interrogate the robustness of the derived classifier. Errors in target pose angle and the inclusion of camouflage, concealment, and deception (CCD) effects are considered in assessing the validity of the classifier. Consideration of different transmitter and receiver combinations and low signal-to-noise ratios are analyzed in the context of deterministic, Gaussian, and uniform target pose uncertainty models. Performance metrics demonstrate increases in classification rates of up to 30% for multiple-transmit, multiple-receive platform configurations when compared to multi-sensor monostatic configurations. A distance measure between probable target classes is derived using information theoretic techniques pioneered by Kullback and Leibler. The derived measure is shown to suggest radar sensor placements yielding better target classification rates. The predicted placements consider two-platform and three-platform configurations in a single-transmit, multiple-receive environment. Significant improvements in classification rates are observed when compared to ad-hoc sensor placement. In one study, platform placements identified by the distance measure algorithm are shown to produce classification rates exceeding 98.8% of all possible platform placements.

Vision has always been one of the most important cognitive tools of human beings. In this regard, the development of image sensors opens up the potential to view objects that our eyes cannot see. One of the most promising capability in some image sensors is their single-photon sensitivity that provides information at the ultimate fundamental limit of light. Time-resolved single-photon avalanche diode (SPAD) image sensors bring a new dimension as they measure the arrival time of incident photons with a precision in the order of hundred picoseconds. In addition to this characteristic, they can be fabricated in complementary metal-oxide-semiconductor (CMOS) technology enabling the integration of complex signal processing blocks at the pixel level. These unique features made CMOS SPAD sensors a prime candidate for a broad spectrum of applications. This thesis is dedicated to the optimization and characterization of quantum imagers based on the SPADs as part of the E.U. funded SUPERTWIN project to surpass the fundamental diffraction limit known as the Rayleigh limit by exploiting the spatio-temporal correlation of entangled photons. The first characterized sensor is a 32×32-pixel SPAD array, named “SuperEllen”, with in-pixel time-to-digital converters (TDC) that measure the spatial cross-correlation functions of a flux of entangled photons. Each pixel features 19.48% fill-factor (FF) in 44.64-μm pitch fabricated in a 150-nm CMOS standard technology. The sensor is fully characterized in several electro-optical experiments, in order to be used in quantum imaging measurements. Moreover, the chip is calibrated in terms of coincidence detection achieving the minimal coincidence window determined by the SPAD jitter. The second developed sensor in the context of SUPERTWIN project is a 224×272-pixel SPAD-based array called “SuperAlice”, a multi-functional image sensor fabricated in a 110-nm CMOS image sensor technology. SuperAlice can operate in multiple modes (time-resolving or photon counting or binary imaging mode). Thanks to the digital intrinsic nature of SPAD imagers, they have an inherent capability to achieve a high frame rate. However, running at high frame rate means high I/O power consumption and thus inefficient handling of the generated data, as SPAD arrays are employed for low light applications in which data are very sparse over time and space. Here, we present three zero-suppression mechanisms to increase the frame rate without adversely affecting power consumption. A row-skipping mechanism that is implemented in both SuperEllen and SuperAlice detects the absence of SPAD activity in a row to increase the duty cycle. A current-based mechanism implemented in SuperEllen ignores reading out a full frame when the number of triggered pixels is less than a user-defined value. A different zero-suppression technique is developed in the SuperAlice chip that is based on jumping through the non-zero pixels within one row. The acquisition of TDC-based SPAD imagers can be speeded up further by storing and processing events inside the chip without the need to read out all data. An on-chip histogramming architecture based on analog counters is developed in a 150-nm CMOS standard technology. The test structure is a 16-bin histogram with 9 bit depth for each bin. SPAD technology demonstrates its capability in other applications such as automotive that demands high dynamic range (HDR) imaging. We proposed two methods based on processing photon arrival times to create HDR images. The proposed methods are validated experimentally with SuperEllen obtaining >130 dB dynamic range within 30 ms of integration time and can be further extended by using a timestamping mechanism with a higher resolution.

Orientadores: Antonio Carlos Bannwart, Oscar Mauricio Hernandez Rodriguez
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências
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Resumo: Neste trabalho, é apresentado o desenvolvimento de uma nova técnica para a medição da espessura do filme de água com alta resolução espacial e temporal em escoamento óleo-água. É proposto o uso de um sistema de medição de capacitância elétrica para medir filmes finos de água na proximidade da parede do tubo. O sistema conta com um sensor planar e foi necessário determinar a melhor geometria via simulações baseadas no Método de Elementos Finitos (FEM) para o caso de escoamento óleo-água. As características comparadas foram a profundidade de penetração do campo elétrico no filme de água, a sensibilidade, a resolução espacial mínima e a resposta quase-linear. Padrões de escoamento óleo-água disperso e anular instável foram estudados numa tubulação vertical de 12 m de comprimento, feita de vidro, com 50,8 milímetros de diâmetro interno. Os fluidos usados foram óleo mineral (com densidade 828 kg/m3 e viscosidade 220 mPas) e água da torneira. O trabalho experimental foi realizado nas instalações de escoamento multifásico do Laboratório de Engenharia Térmica e Fluidos (NETeF) da EESC-USP. Foi medida a espessura média do filme de água usando o sistema capacitivo e uma câmera de vídeo de alta velocidade. Para obter a espessura do filme de água a partir das imagens, foi proposto um algoritmo de pré-processamento e um algoritmo de segmentação que combina vários métodos disponíveis na literatura. Os resultados experimentais do sensor capacitivo mostraram que o sistema pode medir espessuras entre 400 µm e 2200 µm. O escoamento anular instável é caracterizado por grandes flutuações na no sentido do escoamento e na direção do perímetro, e estruturas interfaciais grandes (gotas). Por sua vez, o escoamento disperso tem flutuações menores no sentido do escoamento e na direção do perímetro, e estruturas interfaciais menores (gotículas). Uma estrutura interfacial média no espaço e no tempo é proposta para modelar a interface entre a região próxima à parede do tubo e a região do núcleo, e sua análise foi feita no domínio do tempo e da frequência. Foram estudadas a amplitude, velocidade e o comprimento da estrutura interfacial em cada par transmissor-receptor do sensor. Foi possível estabelecer correlações para a velocidade das estruturas em escoamento de óleo em água
Abstract: The development of a new technique for high spatial and temporal resolution film thickness measurement in oil-water flow is presented. A capacitance measurement system is proposed to measure thin water films near to the wall pipe. A planar sensor was chosen for sensing and some geometries were compared using finite elements method (FEM). The penetration depth, the sensitivity, the minimum spatial resolution (high spatial resolution) and the quasi-linear curve were the analyzed characteristics. Dispersed and unstable-annular oil-water flows patterns were studied in a 12-m long vertical glass pipe, with 50.8 mm of internal diameter, using mineral oil (828 kg/m3 of density and 220 mPa s of viscosity) and tap water. The experimental work was carried out in the multiphase-flow facilities of The Thermal-Fluids Engineering Laboratory (NETeF) of EESC-USP. Experiments with a high-speed video camera and the proposed capacitance system were performed to obtain images of the oil-water flow near the pipe wall. A pre-processing enhancement algorithm and a combined segmentation algorithm are proposed and allowed the measurement of characteristic space and time averaged water film thickness. Experimental results of the capacitive technique showed that the system could measure thickness between 400 µm and 2200 µm. It was possible to recognize and characterize typical behaviors of the two different flow patterns studied. Unstable-annular flow can be described by huge fluctuations on the flow direction and perimeter direction, and big interfacial structures (drops). On the other hand, dispersed flow has tiny fluctuations on the flow direction and perimeter direction, and smaller interfacial structures (droplets). An interfacial structure is suggested in order to model the interface between wall and core regions and it was analyzed in time and frequency domains; amplitude, velocity and wavelength at each pair transmitter-receiver of the sensor were studied. Correlations for the interfacial structure velocity were found for dispersed oil-in-water flow and unstable-annular flow
Doutorado
Explotação
Doutora em Ciências e Engenharia de Petróleo
CAPES

Le développement des capteurs de déplacement à hautes performances du point de vue de la limite de résolution et de l’étendue de mesure, est devenu une demande croissante pour les systèmes mécaniques et mécatroniques. Ce mémoire présente la modélisation, la conception et la fabrication d’un capteur innovant permettant la mesure in-situ et en temps réel du déplacement linéaire d’un axe en mouvement de rotation. Ce capteur est caractérisé par une grande étendue de mesure d’une dizaine de millimètres et par une résolution micrométrique. Après une étude bibliographique portant sur les applications industrielles de ce capteur, une modélisation géométrique de la réflexion de lumière par une surface convexe a été développée. Ce modèle calcule l’intensité lumineuse détectée par le capteur en fonction du rayon de courbure de la surface. Il a montré que la sensibilité augmente en fonction du rayon de courbure (Rc) et que la résolution est optimale pour (Rc=20 mm). Ce modèle géométrique a été validé par des essais expérimentaux dont les résultats ont montré une chute de la sensibilité pour des rayons inférieurs à (Rc= 15 mm). Pour cette raison, et afin de garantir le meilleur fonctionnement du capteur, le rayon de courbure choisi pour la fabrication du réseau de cônes imbriqués a été de 25 mm. Une fois le rayon de courbure optimal choisi, une modélisation géométrique de la mesure de déplacements linéaires sur une grande étendue de mesure par l’utilisation de deux sondes et d’un réseau à cônes imbriqués a été réalisée. La technique d’usinage de haute précision (UHP) a été présentée. Un premier prototype de ce réseau en alliage d’aluminium a été obtenu. Puis, le modèle géométrique a été optimisé pour mieux prendre en compte certaines contraintes de fabrication, ce qui a conduit à l’usinage d’un deuxième prototype ayant des paramètres géométriques légèrement modifiés et un meilleur état de surface pour mieux réfléchir la lumière. Enfin, la validation expérimentale du principe de mesure du capteur à fibres optiques (CFO) a été faite pour ces deux prototypes du réseau de cônes imbriqués, à l’aide d’un montage mécanique, ce qui a permis d’orienter au mieux les sondes du CFO en face du réseau. Cette validation a permis d’évaluer les performances du CFO. Pour le premier prototype, un recouvrement de 30 µm a été vérifié entre les deux signaux. Différentes vitesses de translation et de rotation on été appliquées ; où on a remarqué l’apparition des pics périodiques. Ces pics sont dus à un problème de balourd de l’axe de rotation de la broche ; en augmentant les valeurs de la vitesse de rotation, les pics s’atténuent, car l’inertie de la broche est supérieure. Pour cette raison, on a privilégié de travailler avec des vitesses de rotation élevées et une gamme de vitesse de translation tout en tenant compte de la fréquence d’acquisition. Pour le deuxième prototype, on a validé le principe de mesure avec deux sondes à fibres optiques. Un recouvrement suffisant a été mesuré entre les deux signaux. On a constaté qu’en acceptant davantage de non-linéarité, on augmente la largeur de la zone de recouvrement, ce qui facilite le basculement d’une sonde à l’autre et ainsi assure la continuité de la mesure sur une étendue millimétrique qui est fonction du nombre de cônes, mais l’exactitude de la mesure s’en trouve diminuée. En augmentant la vitesse de translation, on diminue le nombre des points acquis dans la zone de recouvrement, ce qui exige une fréquence d’acquisition plus élevée
The development of displacement sensors with high performances regarding the limit of resolution and the measurement range has become essential for different mechanical systems This Ph.D. presents the modeling, the design and the fabrication of an original fiber-optic sensor. lt is able to measure the linear displacement of a rotating axis. This sensor is characterized by a micrometric resolution on a measurement range of several millimeters. After a bibliography study related to the industrial applications of the sensor, a geometric model of the light reflection by a convex surface has been developed. This model calculates the light intensity detected by the sensor as a function of the radius of curvature (Re); the model shows that the sensitivity increases as a function of the radius of curvature of the reflector (Re) and the limit of resolution is optimal for (Re=20 mm). This geometric model had been experimentally validated; where it was found out that the sensitivity decreases for the radii of curvature less than 15 mm (Re= 15 mm). For that reason, and in order to ensure the best functionality of the sensor, the radius of curvature chosen for the fabrication of the canes assembled grating was 25 mm. Once the optimal radius of curvature fixed a geometric model for the linear displacement measurement on a long measurement range using two fiber-optic probes and one cones assembled grating has been developed. The first prototype of the cones assembled grating was obtained with a high precision turning machine on an aluminum alloy. Afterwards, a second prototype of the cones grating was fabricated; where several parameters have been optimized, such as: the non-inclusion of the fabrication constraints in the geometric model and a better surface roughness of the cones assembled grating. The high precision fabrication technique of the two prototypes was presented. Finally, the experimental validation of the sensor measurement principle with two fiber-optic probes with the help of a mechanical set-up was realized. The mechanical set-up is used to a better orientation of the probes in front of the grating. The experimental validation helped to evaluate the overall sensor performances. For the two prototypes, an overlap of 30 um was verified between two successive signals. Different translation and rotation speeds were applied; where periodical peaks were observed in the output signals. These peaks are due to an unbalanced rotation of the spindle axis of rotation; with high speed values, the peaks are attenuated due to the high inertia of the spindle. For this reason, it is preferred to work at high rotational speeds (20 tr./s) with a consideration of the sampling frequency. This sensor is characterized by a micrometric resolution, on a measurement range of about 10 mm

Le projet PLUME développe des échelles ultra-légères inspirées par le cahier des charges du détecteur de vertex pour le futur e+e- International Linear Collider (ILC). Nos travaux montrent que, pour une énergie de 350 GeV et une luminosité de 250 fb-1, l’ILC donnera accès à des états finals comme Hνν. Les modules PLUME exploitent le concept d’échelles double-face recouvertes de capteurs CMOS afin d’atteindre un budget de matière de 0,35 % en longueurs de radiation. Les tests effectués ont montré que les performances électriques des 12 capteurs intégrés sur ces échelles ne sont pas dégradées. La surface des échelles présente des déformations, mais nous avons mis au point un algorithme spécifique qui permet de corriger leurs effets lors du traitement des données. Finalement, une mesure de la longueur de radiation d’un prototype moins avancé a été réalisée avec un faisceau test au DESY. La valeur obtenue de 0,47±0,02 % en longueurs de radiation correspond au budget attendu
The PLUME project develops ultra-light pixelated layers with specifications driven by the design of a vertex detector at the future e+e- International Linear Collider (ILC). The ILC will give access to final states like Hνν, as this work demonstrates for centre-of-mass energy 350GeV and a luminosity of 250 fb-1. PLUME devices exploit the concept of double-sided ladder spaved with thinned CMOS pixel sensors in order to reach a material budget of 0.35 % of radiation length. The present study validated that simultaneous operation of the 12 CMOS sensors integrated on such light ladders do not impact their electrical behaviour. Surface deformations were observed but a specific algorithm during the off- line analysis was proposed and successfully tested to preserve the native sensor spatial resolution. Finally, a measurement of the material budget of a less advanced ladder prototype has been performedat DESY test beam and yield 0.47±0.02 % of radiation length, matching the expected value

Parmi les 3000 exoplanètes détectées à ce jour, seule une cinquantaine ont été observées par imagerie dont l’avantage est de donner accès à la lumière des exoplanètes, ce qui ouvre la voie aux études spectrales de leur atmosphère et de leur surface. L’imagerie est aussi la seule méthode permettant d’étudier des exoplanètes situées dans les parties externes des systèmes stellaires ainsi que les disques circumstellaires, ce qui est fondamental pour comprendre les différentes étapes de la formation planétaires. Cependant, ces techniques doivent relever deux défis : la faible séparation angulaire qui existe entre une exoplanète et son étoile, ainsi que le contraste entre ces deux objets qui est de l’ordre de 10-4 dans l'infrarouge proche pour des Jupiter jeunes et de l'ordre de 10-10 dans le visible pour des planètes matures telles la Terre et Jupiter. Les instruments actuels utilisent des coronographes pour filtrer la lumière de l'étoile hôte et observer son voisinage ténu. Ils utilisent également des techniques actives qui compensent les effets des aberrations de surface d’onde pour minimiser le niveau des tavelures dans l'image finale. Couplés à des techniques d'imagerie différentielle, ces instruments ont permis la découverte et l'étude d'exoplanètes jeunes et massives, et de disques circumstellaires. Cependant, pour détecter des exoplanètes moins lumineuses et plus proches de leur étoile, les techniques d’imagerie font aujourd’hui l’objet d'une recherche active en laboratoire. Par exemple, l’Observatoire de Paris a développé le banc très haute dynamique (THD) pour tester et optimiser l’association de plusieurs techniques d’imagerie haute dynamique comme le four quadrants phase masque (FQPM) ou la self-coherent camera (SCC) qui est une technique d’analyse de surface d’onde en plan focal.Au début de ma thèse, mes travaux se sont concentrés sur le développement et l’étude de coronographes et d’analyseurs en plan focal pouvant travailler en larges bandes spectrales (typiquement 12,5 % à 40 %). J’ai testé sur le banc THD deux coronographes, le multi four-quadrant phase-mask (MFQPM) et le dual-zone phase-mask (DZPM). J’ai prouvé que le DZPM peut atteindre des contrastes de l’ordre de 4 10-8 pour des séparations angulaires comprises entre 7 et 16 λ/D et une bande spectrale de 250 nm centrée à 640 nm. J’ai également développé et testé une version de la SCC moins sensible au chromatisme appelée multireference self-coherent camera (MRSCC). En la combinant au DZPM, j’ai réussi à atteindre en boucle fermée des contrastes de l’ordre de 4.5 10-8 entre 5 et 17 λ/D pour une bande spectrale de 80 nm centrée à 640 nm. Ces deux résultats sont importants, car ils montrent qu'il est possible de construire un instrument qui atténue la lumière et contrôle activement les aberrations optiques directement à partir de l'image scientifique en large bande spectrale. À la fin de ma thèse, nous avons mis en place une collaboration visant à tester la SCC sur le télescope Hale du mont Palomar. Lors de deux missions auxquelles j’ai participé, nous avons prouvé que la SCC pouvait être associée avec un coronographe de type vortex ce qui n’avait jamais était fait auparavant. De plus, suite aux résultats obtenus sur source interne, nous prévoyons une démonstration sur ciel à l'automne 2016
Among the 3000 exoplanets detected at this time, about 50 have been observed by direct imaging. The benefit of direct imaging is to give access to exoplanet light, paving the way for spectroscopic study of their atmospheres and surfaces. Moreover, direct imaging is also the only method that enables the study of exoplanets located in the outer parts of the stellar systems as well as circumstellar disks, which are fundamental to understand the different stages of planetary formation. However, there are two challenges : the small angular separation between an exoplanet and its star (less than a fraction of 1’’), and the contrast between the two objects which is of the order of 10-4 in near infrared for young Jupiter and of the order of 10-10 in visible light for Earth like planets. Existing instruments use coronagraphs to filter light from the host star and observe its tenuous neighborhood. They also use active techniques in order to minimize, in the final image, the brightness of speckles induced by wavefront aberrations. Coupled with differential imaging techniques, these instruments led to the discovery and study of young and massive exoplanets and circumstellar disks. However, to detect fainter exoplanets closer to their star, imaging techniques are now at the heart of an active research. For example, the Paris Observatory developed the banc très haute dynamique (THD bench) aiming at testing several high contrast imaging techniques and their associations as the four quadrants phase masque (FQPM) and the self-coherent camera (SCC) which is a focal plane wavefront sensor.At the beginning of my PHD, I mainly focused my work on the development and the study of coronagraphs and focal plane wavefront sensors able to work in broadband (between 12,5 % and 40 %). I tested on the THD bench two coronagraphs, the multi four-quadrant phase-mask (MFQPM) and the dual-zone phase-mask (DZPM). I proved that the DZPM is able to reach contrasts of 4 10-8 at angular separations ranging from 7 to 16 λ/D using a spectral bandwidth of 250 nm centered on 640 nm (40 %). I also developed and tested a new version of the SCC, less sensitive to chromatism, called the multireference self-coherent camera (MRSCC). By combining both DZPM and MRSCC, I reached in closed loop contrasts of 4.5 10-8 between 5 and 17 λ/D for a spectral bandwidth of 80 nm centered on 640 nm (12,5 %). These two results are important because they show that it is possible to build an instrument able to reduce the stellar light and actively control optical aberrations directly from a scientific image registered in a large spectral bandwidth which is requiered for the next generation of instruments. During my PHD, we also strated a collaboration to install the SCC at the Palomar Observatory. During two missions in which I took part, we proved, for the first time, that the SCC can be associated with a vortex coronagraph. Finally, based on these results, we plan to demonstrate the SCC concept on sky in the fall of this year

Tato práce se zabývá výběrem vhodného obrazového snímače pro použití v kameře snímající rostliny ve vysokém rozlišení a návrhem vhodného obvodu pro propojení vybraného snímače (SONY IMX253) s vývojovou deskou Avnet MicroZed. Tato práce pojednává o jednotlivých parametrech obrazových snímačů podle kterých je vybírán vhodný obrazový snímač. Je vysvětlen proces výběru vhodného obrazového snímače a podrobněji popsány parametry vybraného snímače. Je naznačena problematika návrhu elektroniky a plošných spojů z hlediska požadavků vysokorychlostních obvodů a citlivých a specifických součástek jako je obrazový snímač. Je nastíněna konfigurace a programování obvodu Xilinx Zynq a nakonec je provedeno zjednodušené teoretické ověření funkčnosti navrženého modulu.

The scope of the current research work was to evaluate the potential of the latest version of Microsoft Kinect sensor (Kinect v2) as an external tracking device for head motion during brain imaging with brain Positron Emission Tomography (PET). Head movements constitute a serious degradation factor in the acquired PET images. Although there are algorithms implementing motion correction using known motion data, the lack of effective and reliable motion tracking hardware has prevented their widespread adoption. Thus, the development of effective external tracking instrumentation is a necessity. Kinect was tested both for Siemens High-Resolution Research Tomograph (HRRT) and for Siemens ECAT HR PET system. The face Application Programming Interface (API) ’HD face’ released by Microsoft in June 2015 was modified and used in Matlab environment. Multiple experimental sessions took place examining the head tracking accuracy of kinect both in translational and rotational movements of the head. The results were analyzed statistically using one-sample Ttests with the significance level set to 5%. It was found that kinect v2 can track the head with a mean spatial accuracy of µ0 < 1 mm (SD = 0,8 mm) in the y-direction of the tomograph’s camera, µ0 < 3 mm (SD = 1,5 mm) in the z-direction of the tomograph’s camera and µ0 < 1 ◦ (SD < 1 ◦ ) for all the angles. However, further validation needs to take place. Modifications are needed in order for kinect to be used when acquiring PET data with the HRRT system. The small size of HRRT’s gantry (over 30 cm in diameter) makes kinect’s tracking unstable when the whole head is inside the gantry. On the other hand, Kinect could be used to track the motion of the head inside the gantry of the HR system.

Les travaux présentés dans cette thèse concernent l'utilisation de données de télédétection inédites pour le suivi des glaciers du massif du Mont Blanc : les images radar à synthèse d'ouverture Haute Résolution (HR) du satellite TerraSAR-X et les prises de vue HR d'un appareil photo numérique automatique. Cette thèse s'attache à montrer l'apport de ces sources d'informations hétérogènes pour mesurer le déplacement de surface des glaciers alpins. Dans cette optique, un examen des méthodes de mesure de déplacement spécifiques à chacun des deux types d'images est réalisé. Deux approches sont alors explorées : la mesure de déplacement monosource dans la géométrie propre à chaque capteur et la mesure de déplacement multisource via des combinaisons intra-capteur et inter-capteur. Alors que l'approche monosource fournit uniquement des mesures 2D du déplacement, les mesures multisources permettent pour la première fois d'estimer des champs de déplacement 3D de la surface des glaciers du Mont Blanc. Les mesures ont été réalisées sur plusieurs séries temporelles d'images couvrant la période 2008-2009 pour quatre glaciers du massif du Mont Blanc (Argentière, Mer de Glace/Leschaux, Bossons et Taconnaz). Dans le contexte du changement climatique, ces mesures de déplacement de surface fournissent une donnée intéressante en glaciologie pour contraindre les modèles numériques d'écoulement et d'évolution des glaciers.

En télédétection optique, les modèles de transfert radiatif (T-R) ont pour but de simuler la mesure radiométrique des capteurs spatiaux qui observent le système "Terre - Atmosphère". La modélisation des mesures de couverts végétaux est en général limitée au niveau de la représentation du paysage et du T-R associé. Cette thèse a permis de transformer le modèle 3-D de T-R DART (brevet : PCT/FR 02/01181) en un modèle multispectral simulant les images de télédétection optique (thermique inclus) de tout paysage urbain et naturel, avec relief et atmosphère, pour tout capteur spatial/aéroporté. Ce nouveau modèle a été validé par comparaison avec d'autres modèles (expérience RAMI-3, Centre Commun de Recherche, Italie) et avec des mesures in situ et aéroportées (République Tchèque). In fine, une méthode d'inversion a été développée. Elle a permis d'utiliser DART pour évaluer l'impact de la modélisation sur l'extraction du LAI d'une forêt de conifères avec des images hyperspectrales THR
In optical remote sensing, radiative transfer (R-T) models aim to simulate radiometric measurement of spatial sensors that spot “Landscape-Atmosphere” system. The modeling of vegetation canopies measurements is generally limited to landscape representation and R-T modeling. This thesis allowed transforming a 3-D R-T model DART (patent : PCT/FR 02/01181) to multispectral model simulating optical remote sensing images (thermal infrared included) of any natural and urban landscape with relief and atmosphere for any spatial/airborne sensor. This new model was validated by models intercomparison (RAMI-3 experience, Joint Research Centre, Italy) and with in situ and airborne measurements (Czech Republic). In fine, an inversion method was developed. It allowed using DART for evaluating the modeling impact on LAI estimation of coniferous forest using hyperspectral VHR images

Asservissement par ordinateur de la mise en coïncidence et du déplacement en synchronisme des fonctions d'appareil de deux éléments optiques conjugués: un interféromètre de Fabry-Pérot à balayage par variations d'indice et un monochromateur à réseau. Pour l'asservissement du Fabry-Pérot, développement d'un capteur d'indice à haute résolution à partir d'un interféromètre de Michelson du type Sanders

In the absence of a fusion neutron source, research on the structural integrity of materials in the fusion environment relies on current fission data and simulation methods. Through investigation of the Fe-Cr system, this detailed study explores the challenges and limitations in the use of currently available radiation sources for fusion materials research. An investigation of ion-irradiated Fe12%Cr using nanoindentation with a cube corner, Berkovich and spherical tip, and micro-cantilever testing with two different geometries, highlighted that the measurement of irradiation hardening was largely dependent on the type of test used. Selected methods were used for the comparison of Fe6%Cr irradiated by ions and neutrons to a dose of 1.7dpa at a temperature of 288°C. Micro-cantilever tests of the Fe6%Cr alloy with beam depths of 400 to 7000nm, identified that size effects may significantly obscure irradiation hardening and that these effects are dependent on radiation conditions. Irradiation hardening in the neutron-irradiated alloy was approximately double that of the ion-irradiated alloy and exhibited increased work hardening. Similar differences in hardening were observed in an Fe5%Cr alloy after ion-irradiation to a dose of 0.6dpa at 400°C and doses rates of 6 x 10^-4dpa/s and 3 x 10^-5dpa/s. Identified by APT, it was shown that increased irradiation hardening was likely to be caused by the enhanced segregation of Cr observed in the alloy irradiated with the lower dose rate. These observations have significant implications for future fusion materials research in terms of the simulation of fusion relevant radiation conditions and micro-mechanical testing.

Un microscope à force atomique (AFM) est utilisé pour caractériser des matériaux isolant ou semi-conducteur avec une résolution pouvant atteindre l'échelle atomique. Ce microscope est constitué d'un capteur de force couplé à une électronique de contrôle pour pouvoir correctement caractériser ces matériaux. Parmi les différents modes (statique et dynamique), nous nous focalisons essentiellement sur le mode dynamique et plus particulièrement sur le fonctionnement sans contact à modulation de fréquence (FM-AFM). Dans ce mode, le capteur de force est maintenu comme un oscillateur harmonique par le système d'asservissement. Le projet ANR Pnano2008 intitulé : ”Cantilevers en carbure de silicium à piézorésistivité métallique pour AFM dynamique à très haute fréquence" a pour objectif d'augmenter significativement les performances d'un FM-AFM en développant un nouveau capteur de force très haute fréquence. Le but est d'augmenter la sensibilité du capteur et de diminuer le temps nécessaire à l'obtention d'une image de la surface du matériau. Le système de contrôle associé doit être capable de détecter des variations de fréquence de 100mHz pour une fréquence de résonance de 50MHz. Etant donné que les systèmes présents dans l'état de l'art ne permettent pas d'atteindre ces performances, l'objectif de cette thèse fut de développer un nouveau système de contrôle. Celui-ci est entièrement numérique et il est implémenté sur une carte de prototypage basée sur un FPGA. Dans ce mémoire, nous présentons le fonctionnement global du système ainsi que ses caractéristiques principales. Elles portent sur la détection de l'écart de fréquence de résonance du capteur de force
An atomic force microscope (AFM) is used to characterize insulating materials or semiconductors with a resolution up to the atomic length scale. The microscope includes a force sensor linked to a control electronic in order to properly characterize these materials. Among the various modes (static and dynamic), we focus mainly on the dynamic mode and especially on the frequency modulation mode (FM-AFM). In this mode, the force sensor is maintained as a harmonic oscillator by the servo system. The research project ANR Pnano2008 entitled: "metal piezoresistivity silicon carbide cantilever for very high frequency dynamic AFM" aims to significantly increase the performance of a FM-AFM by developing new very high frequency force sensors. The goal is to increase the sensitivity of the sensor and to decrease the time necessary to obtain topography images of the material. The control system of this new sensor must be able to detect frequency variations as small as 100mHz for cantilevers with resonance frequencies up to 50MHz. Since the state-of-the-art systems doe not present these performances, the objective of this thesis was to develop a new control system. It is fully digital and it is implemented on a FPGA based prototyping board. In this report, we present the system overall functioning and its main features which are related to the cantilever resonant frequency detection. This detection is managed by a phase locked loop (PLL) which is the key element of the system

碩士
國立交通大學
機械工程系所
107
In this study, we used the common and low-cost optical flow sensor as the core of image processing. We simply adopted a set of designed discs with pattern sticker on it as a checkerboard disk to transfer the angle variation (rotation) to a linear motion. Angle variation is obtained using lower cost sensors. Therefore, significantly reduction of the manufacturing cost of the grating, which is inside the optical angle encoder could be made. Angle sensors can be used more widely and universally in a wide variety of designs in the foreseeable future.

碩士
國立雲林科技大學
電子與資訊工程研究所
99
This work presents a current mode linear temperature sensor through summing two temperature-dependent current sources driven in particular region with complementary temperature dependency. The nonlinear effects induced by carrier mobility and threshold voltage are therefore cancelled, indeed, not only improves linearity but also enhances driving capability. In addition, a window comparator is adopted to convert current quantity into representation of pulse width. To increase the conversion accuracy, we develop a differential calibration to reduce the unideal effect of comparator. The interlaced time-digital-converter which consists of two sub-converters with coarse and fine scale respectively is then used to quantify the converted representation of pulse width. By controlling sub-converters on and off alternately, the wide pulse width can be calculated effectively and the narrow pulse width can be precisely acquired as well. Under the temperature range from -55℃ to 125 ℃, the temperature resolution is 0.1℃ and the maximum error is within ± 0.4℃.

碩士
國立臺灣大學
機械工程學研究所
93
The study develops an integrated CMOS flow sensor applied in monitoring the flow condition in thermal module. The flow sensor has a high resolution in low speed air flow field. This sensor includes micro structures and mixed signal processor in 2 mm square chip die size fabricated by the standard CMOS process. The microstructures of sensor consist of a polysilicon micro heater and the thermopiles array. The center micro heater encircled by the temperature sensors generates the thermal plume. As the sensor is positioned against the flow, the thermal plume will be pushed towards to the temperature sensors array and the temperature difference can be converted into the voltage to determine the air flow speed. The flow sensors arrayed in four sides gives both output voltages in x-direction and y-direction, and the sensor makes splendid accomplishments as it is operated under impinging flow. Combining signal output from two perpendicular sensors, the module can make three components of velocity measurement. The sensitivity of the flow sensor can be indicated as 0.7 mV/ (m/s) under impinging flow and 0.001 m/s velocity measurement resolution is achieved. The air flow speed ranges from 0.1 to 3.6 m/s.

碩士
國立成功大學
機械工程學系碩博士班
100
Photonic crystals which possess the photonic bandgap due to their periodic structures have attracted intensive interests in science and technologies. Similar to electrons in solids, photons with some specific energy are forbidden within the photonic bandgap. In this study, we explore an ultrasensitive refractive index sensor using a magnetic photonic crystal (MPC) composed of a triangular lattice array of air holes with a Si background. Consider a microcavity created by altering the radius of an air hole in the middle of the photonic crystal. The defect filled with gyrotropic materials can serve as a refractive index sensor. By applying the external magnetic field in the y direction to the gyrotropic magnetic medium, we observe different refractive indices of the right-hand circular polarization mode and left-hand circular polarization mode. When the external magnetic field is applied in the y direction, the sensor has a better quality factor and the sensitivity. Furthermore we optimize the sensor by modulating the gyrotropic factor, which varies with the magnetic field applied in the y direction. Numerical results reveals that the proposed sensor has obtained the better quality factor, sensitivity and resolution of the sensor than preview ones. Finally, we show the characteristics of high resolution in the gyrotropic sensor by measuring the common gases.