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Développement de diodes laser à faible largeur de raie pour le pompage atomique et d'un MOPA (Master Oscillator Power Amplifier) à 780 nm pour le refroidissement d'atomes de Rubidium et la réalisation de capteurs inertiels / Development of laser diodes with narrow linewidth for atomic pumping and a MOPA (Master Oscillator Power Amplifier)at 780 nm for cooling Rubidium atoms and realization of inertial sensorsBebe Manga Lobe, Joseph Patient 24 April 2015 (has links)
Cette thèse de doctorat a été réalisée au sein du III-VLab, en partenariat avec l’Institut d’Electronique du Sud (IES). L’objectif de ce travail de thèse vise d’une part à l’optimisation des performances des diodes laser DFB émettant à 780 nm et le développement d’une source plus compacte (MOPA) à 780nm, intégrant de façon monolithique l’oscillateur maître (laser à rétro-action répartie ou DFB) et l’amplificateur de puissance, et d’autre part, à appréhender les phénomènes de bruit, permettant d’évaluer la qualité technologique des lasers. Les développements autour de la longueur d’onde 780 nm, se sont organisés en plusieurs thématiques : les lasers Fabry-Perot et DFB, les amplificateurs (SOA), les MOPA et l’étude du bruit des lasers. Nous avons étudié des structures de différentes épaisseurs de puits quantiques (160Å, 135 Å et 145 Å). La comparaison des performances globales des différentes structures de lasers larges, loin d’être évidente, nous a permis de choisir celle intégrant un puits quantique de 160 Å, pour la réalisation des lasers Fabry-Perot à ruban étroit (3µm à 4µm). Nous avons obtenu sur des lasers larges, de 3 mm de long, bruts de clivage, une puissance d’environ 5 watts par face pour un courant d’injection continu autour de 10 A. Les simulations et caractérisations électro-optiques menées sur des lasers ridge Fabry-Perot, ont servi à affiner le dessin des DFB à 780 nm, par rapport aux briques de base existantes du III-V Lab, et à proposer des structures à cavités optiques larges et super-large (LOC et SLOC) optimisées, en termes de puissance, qualités de faisceau et spectrale.Les mesures de bruits, appuyées d’un modèle de bruit électrique, ont permis d’extraire une valeur du paramètre de Hooge de 2,1.10^-3 pour les lasers ridge, en accord avec la littérature, et qui correspond à une bonne qualité de matériau et technologique des lasers. Différents types d’amplificateurs optiques évasés ont été dessinés, réalisés et caractérisés. Les caractérisations des diverses géométries de SOA, ont donné dans l’ensemble, des valeurs de gain comprises entre 19dB et 25dB. Nous avons obtenu respectivement pour les structures d’amplificateurs à guidages entièrement par l’indice (GI), entièrement par le gain (GG) et mixte (GM), des puissances de 500mW, 750mW et 1W. L’ensemble des résultats obtenus avec ces structures sont prometteurs pour l’intégration monolithique avec le DFB. En ce qui concerne le MOPA, trois approches ont été étudiées: MOPA droit, DFB et amplificateur tiltés de 7° (par rapport à la normale aux faces clivées), et la plus prometteuse mais plus complexe, intégrant le DFB droit et l’amplificateur tilté de 7°, avec une section courbe entre les deux. La prise en compte de l’ensemble des résultats lasers Fabry-Perot, DFB et des résultats d’amplificateurs, nous ont permis de proposer des dessins MOPA originaux. Le dessin du masque réalisé, intègre toutes ces configurations de MOPA, et en plus, des SOA et DFB, qui seront utilisés comme témoins de test lors des caractérisations. / This thesis has been realized in III-VLab in collaboration with the South Electronic Institute in Montpellier. The aim of this work focuses in one hand, on the performance improvement of DFB's diode lasers emitting at 780 nm, and the advanced design of a compact semiconductor laser diode (Master Oscillator Power Amplifier), integrating monolithically the master oscillator (DFB for Distributed Feedback laser); in the other hand, using the noise phenomenon’s studies as a tool, for validating of our laser technologies. The Developments round the 780 nm wavelength, have been divided into different thematic: Fabry-Perot and DFB, Semiconductor Optical Amplifiers (SOA), MOPA, and the lasers noise’s study. We have studied structures with different quantum well thickness (160Å, 135 Å and 145 Å). The comparison of global performances of broad area lasers from these different structures, far to being obvious, allowed us to choose the one that integrates the 160-Å-thickness of quantum-well, for the realization of ridge Fabry-Perot lasers of 3 to 4-µm-of width. We obtained with broad area lasers, as cleaved, with 3-mm cavity lengths, an output power around 5 watts per facet, in continuous bias current around 10 AModellings and electro-optics characterizations performed on ridge Fabry-Perot lasers, allowed to refine DFB lasers at 780 nm, in comparison of the existing building blocks in the lab; we proposed new optimized structures with Large and Super Large Optical Cavities(LOC and SLOC), in terms of optical output power, beam and spectral qualities.The noise measurements with electrical noise modelling, allowed us to extract a value of Hooge’s parameter of 2,1.10^-3, quite in agreement with literature for such lasers, which corresponds to a good material quality and laser technology.Different types of flared SOA have been designed, realized and characterized. The characterizations of various SOA geometries, have given in general, values of gain between 19 dB to 25 dB. With SOAs of types: fully Index Guiding (IG), fully Gain Guiding (GG) and Mixed Guiding (MG), we have respectively obtained 500 mW, 750 mW and 1 W. All the results obtained with these structures are promising for monolithic integration with DFB. Regarding the MOPA, three approaches have been studied. The straight MOPA, the approach of SOA and DFB with 7° tilt(relative to the normal to cleaved facets), and the most complex, but promising approach, integrating the SOA with 7° tilt, and straight DFB, with a bend section between them. By taking into account all the results obtained on Fabry-Perot lasers, DFB, and SOA results, we were able to propose original MOPA designs. The layout drawing has been realized, all the MOPA configurations and additional, DFB and SOA devices, have been included on it. They will be used as test structures for characterizations.
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Un sistema de navegación de alta integridad para vehículos en entornos desfavorablesToledo Moreo, Rafael 03 March 2006 (has links)
Algunas aplicaciones de carretera actuales, tales como los servicios de información al viajero, llamadas de emergencia automáticas, control de flotas o telepeaje eletrónico, requieren una solución de calidad al problema del posicionamiento de un vehículo terrestre, que funcione en cualquier entorno y a un coste razonable. Esta tesis presenta una solución a este problema, fusionando para ello la información procedente principalmente de sensores de navegación por satélite y sensores inerciales. Para ello emplea un nuevo filtro de fusion multisensorial IMM-EKF. El comportamiento del sistema ha sido analizado en entornos reales y controlados, y comparado con otras soluciones propuestas. Finalmente, su aplicabilidad al problema planteado ha sido verificada. / Road applications such as traveller information, automatic emergency calls, freight management or electronic fee, collection require a onboard equipment (OBE) capable to offer a high available accurate position, even in unfriendly environments with low satellite visibility at low cost. Specifically in life critical applications, users demand from the OBEs accurate continuous positioning and information of the reliability of this position. This thesis presents a solution based on the fusion of Global Navigation Satellite Systems (GNSS) and inertial sensors (GNSS/INS), running an Extended Kalman Filter combined with an Interactive Multi-Model method (IMM-EKF). The solution developed in this work supplies continuous positioning in marketable conditions, and a meaningful trust level of the given solution. A set of tests performed in controlled and real scenarios proves the suitability of the proposed IMM-EKF implementation, as compared with low cost GNSS based solutions, dead reckoning systems and single model extended Kalman filter (SM-EKF) solutions.
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Design Of Two-Axis Displacement-Amplifying Compliant Mechanisms Using Topology OptimizationDinesh, M 01 July 2008 (has links)
This thesis deals with the design of two-axis displacement-amplifying compliant mechanisms (DaCMs) using topology optimization. The two-axis compliant mechanisms considered here are XY positioners and two-axis inertial sensors. A building block approach, with several single-axis DaCMs as building blocks, is used to conceive designs of compliant platforms that provide two orthogonal and independent movement of a common platform. Spring-mass-lever (SML) models of these designs are developed to simplify the analysis and design of the complicated arrangements of building blocks.
The XY positioners designed in this work have perfectly de-coupled motion without compromising on the frequency; the best design of the stage has a displacement amplification of five resulting in the enhanced range of 4.2 % of the mechanism size–a significant improvement from the 1.67 %, the maximum range of the designs reported so far. Nearly 100% improvement is observed in the sensitivity of the two-axis accelerometer as compared with an existing design that occupied the same area.
Multiple prototypes of XY positioners were fabricated on polypropylene sheets using CNC machining; and on spring steel and aluminium using wire-cut electro discharge machining. Mask layouts for two-layer two-axis accelerometers are designed for micro-fabrication using reactive ion etching and wafer bonding.
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Telemetrie pro formuli Dragon IV / Telemetry for Dragon IV FormulaBezdíček, Jan January 2014 (has links)
The aim of this master's thesis was to design and construct complete telemetry system for the student formula Dragon IV constructed for international Formula Student competition. At first, the work deals with the measurement of the physical quantities, telemetry system and automotive sensors of the formula, their mutual communication and communication with the CAN bus. It also describes the procedure of hardware design including choosing right inertial sensors and a GPS module and their using in telemetry system. The work contains materials for production of two-layer printed circuit board extending the microcomputer BeagleBone Black on the inertial sensors and the GPS module. The bigger part of the telemetry system is the firmware for hardware and software for the computer user. Both written in programming language C++ and C# are included in this work as well. This user application serves for wireless receiving data from the hardware and their showing and logging. In addition this user application can be used for wireless hardware configuration. The final product is the complete telemetry system and it is suitable for selling to end customer.
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9DOF senzor pro měření orientace zbraně v prostoru / 9DOF sensor for weapon orientation measurementRůžička, Jiří January 2017 (has links)
This thesis deals with multi-axis position sensors, their nature and individual parts and types of these sensors. It is outlined their historical origin and the most used modern types, such as micro-electro-mechanical sensors. Further, the properties of these sensors, error sources and their compensation are discussed. Output data formats are also discussed here, such as Euler angles, their calculation and applications. The selected sensor is implemented in the simulator electronics, and the graphical application demonstrates its functions.
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Framework zur Innenraumpositionierung unter Verwendung freier, offener Innenraumkarten und InertialsensorikGraichen, Thomas, Weichold, Steffen, Bilda, Sebastian 07 February 2017 (has links)
In der vorliegenden Publikation wird ein Verfahren beschrieben, dass eine infrastrukturlose Positionierung im Inneren von Gebäuden ermöglicht. Unter infrastrukturlos wird in diesem Zusammenhang die autarke Positionierung eines Systems auf Basis seiner Inertialsensorik ohne den Einsatz von im Gebäude installierter Zusatzlösungen, wie Funksysteme, verstanden. Aufgrund der insbesondere über die Zeit erhöhten Fehlerbehaftung solcher Sensoren werden bei diesem Verfahren Innenraumkarten in den Lokalisierungsprozess einbezogen. Diese Kartendaten erlauben den Ausschluss invalider Positionen und Bewegungen, wie das Durchqueren von Wänden, und ermöglichen somit eine wesentliche Verbesserung der Ortungsgenauigkeit.
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Einfluss des Experimentalraums auf biomechanische Messungen beim Laufen in unterschiedlichen LaufschuhenZaumseil, Falk 16 August 2017 (has links)
Die Fortbewegung des Menschen – ob gehend oder laufend – war und ist bis zum heutigen Tag im Fokus des wissenschaftlichen Interesses. Dabei gehört die Durchführung von etwaigen Studien im Labor zu einer anerkannten methodischen Verfahrensweise. Durch die stete technologische Weiterentwicklung von Messsystemen, bestehen nunmehr veränderte Möglichkeiten, wodurch das Laufen des Menschen in seinem natürlichen Bewegungsraum quantifiziert werden kann.
Ziel dieser Arbeit war es, den Einfluss des Experimentalraums auf das Laufen zu untersuchen. Zusätzlich wurde dabei die Rolle von drei Laufschuhen unterschiedlicher Kategorien genauer betrachtet. Für die Erhebung der zum Vergleich notwendigen Messgrößen diente zum einen ein Inertialsensor-System, um die Kinematik der Läufer zu erfassen und zum anderen EMG-System, um Rückschlüsse auf deren muskulären Status ziehen zu können.
In den Ergebnissen zeigte sich, dass nicht nur der Laufschuh sondern auch der Experimentalraum mit seinen jeweiligen Gegebenheiten Einfluss auf den Laufstil der Probanden nahmen. Generell kann aus den Ergebnissen abgeleitet werden, dass auf Grund der besseren Laufrhythmik im Feld, die Läufer einen messbar effizienteren Laufstil aufwiesen.
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Exploration of Displacement Detection Mechanisms in MEMS SensorsThejas, * January 2015 (has links) (PDF)
MEMS Sensors are widely used for sensing inertial displacements. The displacements arising out of acceleration /Coriolis effect are typically in the range of 1 nm-1 m. This work investigates the realization of high resolution MEMS inertial sensors using novel displacement sensing mechanisms.
Capacitance sensing ASIC is developed as part of conventional electronics interface with MEMS sensor under the conventional CMOS-MEMS integration strategy. The capacitance sense ASIC based on Continuous Time Voltage scheme with coherent and non-coherent demodulation is prototyped on AMS 0.35 m technology. The ASIC was tested to sense C = 3.125 fF over a base of 2 pF using on-chip built-in test capacitors. Dynamic performance of this ASIC was validated by interfacing with a DaCM MEMS accelerometer. 200milli-g of acceleration (equivalent to a C = 2.8 fF) over an input frequency of 20Hz is measurable using the developed ASIC. The observed sensitivity is 90mV/g. The ASIC has several programmable features such as variation in trim capacitance (3.125 fF-12.5 pF), bandwidth selection (500 Hz-20 kHz) and variable gain options (2-100).
Capacitance detection, a dominant sensing principle in MEMs sensors, experiences inherent limitation due to the role of parasitics when the displacements of interest are below 5 nm range. The capacitive equivalence ( C) for the range of displacements of the order of 5 nm and below would vary in the range atto-to-zepto farad. Hence there is a need to explore alternative sensing schemes which preferably yield higher sensitivity (than those offered by the conventional integration schemes) and are based on the principle of built-in transduction to help overcome the influence of parasitics on sensitivity.
In this regard, 3 non-conventional architectures are explored which fall under the direct integration classification namely:
(a) Sub-threshold based sensing
(b) Fringe field based sensing and
(c) Tunneling current based sensing.
a) In Sub-threshold based sensing, FET with a suspended gate is used for displacement sensing. The FET is biased in the sub-threshold region of operation. The exponential modulation of drain current for a change in displacement of 1 nm is evaluated using TCAD, and the in uence of initial air-gap variation on the sensitivity factor ( ID=ID) is brought out.
For 1% change in air gap displacement (i.e., TGap/TGap, the gap variation resulting due to the inertial force / mass loading) nearly 1050% change in drain current( ID=ID) is observed (considering initial air gaps of the order 100 nm). This validates the high sensitivity offered by the device in this regime of operation. A comparison of sensitivity estimate using the capacitive equivalence model and TCAD simulated model for different initial air-gaps in a FD-SOI FET is brought out. The influence of FDSOI FET device parameters on sensitivity, namely the variation of TSi, TBox, NA and TGap are explored.
CMOS compatibility and fabrication feasibility of this architecture was looked into by resorting to the post processing approach used for validating the sub-threshold bias concept. The IMD layers of the Bulk FETs fabricated through AMS 0.35 technology were etched using BHF and IPA mixture to result in a free standing metal (Al) layers acting as the suspended gate. The performance estimate is carried out considering specific Equivalent Gap Thickness (EGT) of 573 nm and 235 nm, to help overcome the role of coupled electrostatics in influencing the sensitivity metric. The sensitivity observed by biasing this post processed bulk FET in sub-threshold is 114% ( ID=ID change) for a 59% ( d/d change). The equivalent C in this case is 370 aF.
b) In Fringe eld based sensing approach, a JunctionLess FET (JLFET) is used as a depletion mode device and an out-of-plane gate displacement would help modulate the device pinch-o voltage due to fringe field coupling. The resulting change in the gate fringe field due to this displacement modulates the drain current of the JunctionLess FET. The displacement induced fringe field change (relative to the FET channel) brings about a distinct shift in the ID-VG characteristics of the JLFET. For displacement
d = 2 nm, the JLFET with a channel doping of ND = 8X1018cm 3 and a bias point of VG = -47.7 V, 98% enhancement in sensitivity is observed in 3D TCAD simulations. The equivalent C in this case is 29 zF. The role of ground-planes in the device operation is explored.
c) In the tunneling current based sensing approach, the beams fabricated using the SOI-MUMPS process are FIB milled so as to create very ne air gaps of the order of nearly 85 nm. Under high electric fields of the order > 8 MV/cm, the lateral displacement based tunneling sensor offers enhanced change in sensitivity for an induced external force at a fixed DC bias. When integrated as an array with varying electrode overlap, this technique can track displacements over a wide range. With the initial beam overlap as 1.2 m, for a lateral displacement of 1.2 m, a 100% change in sensitivity ( ID=ID) is observed. The effect of fringe field can be completely neglected here unlike its capacitive beam equivalent.
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Měřicí zařízení pro sportovní analýzu využívající senzory inerciálních veličin / Measurement unit for sports analysis with inertial sensorsDugas, Martin January 2018 (has links)
Master's thesis is dealing with desgin of a measuring unit incorporating inertial sensors, used for analysis in canoe sprint. Data from a three-axis accelerometer and a three-axis gyroscope were combined using an extended Kalman filter, yielding speed, roll, pitch and yaw of the boat and stroke rate. Calculated values were verified by a GPS. Furthermore, parameters describing dynamic behaviour of the system were identified, allowing an inclusion of dynamic quantities like force and power into the analysis.
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Wearable Systems For Health Monitoring Towards Active AgingMajumder, Sumit January 2020 (has links)
Global rise in life expectancy has resulted in an increased demand for affordable healthcare and monitoring services. The advent of miniature and low–power sensor technologies coupled with the emergence of the Internet–of–Things has paved the way towards affordable health monitoring tools in wearable platforms. However, ensuring power–efficient operation, data accuracy and user comfort are critical for such wearable systems. This thesis focuses on the development of accurate and computationally efficient algorithms and low–cost, unobtrusive devices with potential predictive capability for monitoring mobility and cardiac health in a wearable platform.
A three–stage complementary filter–based approach is developed to realize a computationally efficient method to estimate sensor orientation in real–time. A gradient descent–based approach is used to estimate the gyroscope integration drift, which is subsequently subtracted from the integrated gyroscope data to get the sensor orientation. This predominantly gyroscope–based orientation estimation approach is least affected by external acceleration and magnetic disturbances.
A two–stage complementary filter–based efficient sensor fusion algorithm is developed for real–time monitoring of lower–limb joints that estimates the IMU inclinations in the first stage and uses a gradient descent–based approach in the second stage to estimate the joint angles. The proposed method estimates joint angles primarily from the gyroscope measurements without incorporating the magnetic field measurement, rendering the estimated angles least affected by any external acceleration and insensitive to magnetic disturbances.
An IMU–based simple, low–cost and computationally efficient gait–analyzer is developed to track the course of an individual's gait health in a continuous fashion. Continuous monitoring of gait patterns can potentially enable detecting musculoskeletal or neurodegenerative diseases at the early onset. The proposed gait analyzer identifies an anomalous gait with moderate to high accuracy by evaluating the gait features with respect to the baseline clusters corresponding to an individual’s healthy peer group. The adoption of a computationally efficient signal analysis technique renders the analyzer suitable for systems with limited processing capabilities.
A flexible dry capacitive electrode and a wireless ECG monitoring system with automatic anomaly detection capability are developed. The flexible capacitive electrode reduces motion artifacts and enables sensing bio–potential over a dielectric material such as cotton cloth. The virtual ground of the electrode allows for obtaining single–lead ECG using two electrodes only. ECG measurements obtained over different types of textile materials and in presence of body movements show comparable performance to other reported ECG monitoring systems. An algorithm is developed separately as a potential extension of the software to realize automatic identification of Atrial Fibrillation from short single–lead ECGs.
The association between human gait and cardiac activities is studied. The gait is measured using wearable IMUs and the cardiac activity is measured with a single–lead handheld ECG monitor. Some key cardiac parameters, such as heart rate and heart rate variability and physical parameters, such as age and BMI show good association with gait asymmetry and gait variation. These associations between gait and heart can be useful in realizing low–cost in–home personal monitoring tool for early detecting CVD–related changes in gait features before the CVD symptoms are manifested. / Thesis / Doctor of Philosophy (PhD) / Wearable health monitoring systems can be a viable solution to meet the increased demand for affordable healthcare and monitoring services. However, such systems need to be energy–efficient, accurate and ergonomic to enable long–term monitoring of health reliably while preserving user comfort.
In this thesis, we develop efficient algorithms to obtain real–time estimates of on–body sensors' orientation, gait parameters such as stride length, and gait velocity and lower–limb joint angles. Furthermore, we develop a simple, low–cost and computationally efficient gait–analyzer using miniature and low–power inertial motion units to track the health of human gait in a continuous fashion.
In addition, we design flexible, dry capacitive electrodes and use them to develop a portable single–lead electrocardiogram (ECG) device. The flexible design ensures better conformity of the electrode to the skin, resulting in better signal quality. The capacitive nature allows for obtaining ECG signals over insulating materials such as cloth, thereby potentially enabling a comfortable means of long–term cardiac health monitoring at home. Besides, we implement an automatic anomaly detection algorithm that detects Atrial Fibrillation with good accuracy from short single–lead ECGs.
Finally, we investigate the association between gait and cardiac activities. We observe that some important cardiac signs, such as heart rate and heart rate variability and physical parameters, such as age and BMI show good association with gait asymmetry and gait variation.
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