ROBEX is a unique research project combining Airbus Defence and Space’s robotics expertise with deep-sea exploration technology to discover more about the most extreme environments environments known to man. As a part of this project, a deep-sea glider called MOTH, is under development with the objective to determine whether gliders can be used as a platform for bathymetric and electromagnetic soundings of the seafloor as well as for new water column research. This master’s thesis aims to design and implement the MOTH glider’s control system. The glider will have an independent emergency system, a power unit, an on-board computer (OBC), actuators, navigation sensors and scientific measurement instruments which can be swopped between missions and are connected via remote terminal units. The selected OBC is a Linux embedded Axotec GX-6300 with RS232 and CAN bus interfaces, as selected in the electrical architecture, and the chosen operative system is Linux Debian. The glider communicates with GNS/Iridium antenna and also has an ethernet cable link for ground station operations and a future option of an acoustic transceiver. To control actuation, the glider is equipped with a rudder, a left and a right wing flap, a moveable mass and a buoyancy tank. It travels in sawtooth patterns and is therefore always descending, ascending or transitioning during operation and at times ascending all the way to the surface to transmit and receive data via satellite communication. A model based feedback controller for longitudinal control has been programmed based on the equations of motion described in this report. The modelled longitudinal trajectory is as desired until a transition point is reached, the model is, presumable because of the uncertainty of the model parameters, unstable as the actuators are unable to correct the pitch angle. An AHRS navigation sensor emulator and an OBC emulator have been programmed to simulate the communication between these two and the emulated system is well operating both as a continuous stream and for polling data. The emulator and the pitch controller, when updated parameter values are available, will be used for simulation and verification tests in the laboratory environment. The ROBEX alliance will, if the objectives with the MOTH glider are met, continue to design gliders with the aim to increase the maximum duration time and speed in order to reach greater depths of the oceans.

Music- and video consumption has rapidly changed during the last years and a growing number of consumers use different streaming services which allow for greater interaction with other users than was previously possible. Meanwhile a growing focus within the scientific world has been placed on consumers’ ability to co-create value with other users. A mixed method study was consequently conducted to investigate how streaming companies help consumers co-create value by facilitating customer-to-customer relationships. The qualitative approach showed that there was a clear ambition by streaming companies to utilize C2C relationships to market their products and help co-create value. The quantitative approach showed, however, that their efforts were not always effective and that focusing on other aspects of streaming services may provide more value for the consumer. / Video- och musikkonsumtion har snabbt förändrats de senaste åren och en växande andel konsumenter använder sig idag av streamingtjänster som erbjuder möjligheten att interagera med andra användare. Under samma period har ett växande fokus placerats på användares möjlighet att samskapa värde med andra konsumenter. En blandad metod användes för att undersöka hur olika streamingbolag främjar konsumentinteraktioner för att hjälpa samskapande-processen. Det kvalitativa tillvägagångssättet gjorde det tydligt att streamingbolag har en ambition att använda sig av C2C-interaktioner för att marknadsföra sina produkter och göra dem mer värdefulla för konsumenten. Det kvantitativa tillvägagångssättet visade däremot att deras strävan att skapa värde inte alltid var framgångsrik och att de sannolikt skulle kunna skapa mer värde på andra sätt.

Le travail de recherche présenté dans ce mémoire est dédié au filtrage des multiples de la tranche deau sur les données sismiques OBC (Ocean Bottom Cable).<br />Ces multiples générés par les réflexions successives entre la surface de l'eau et le fond marin détériorent considérablement la qualité des images sismiques.<br /><br /> Nous proposons dans ce document une méthode robuste de filtrage de ces multiples par "sommation PZ" dans le domaine (Tau,p).<br />Nous commençons par modéliser les enregistrements de l'hydrophone et du géophone en OBC dans le domaine des ondes planes harmoniques.<br />Nous montrons que ces modèles s'expriment en fonction des arrivées primaires et des multiples de la colonne d'eau.<br />Cette modélisation nous permet de proposer un algorithme de filtrage des multiples qui tient compte non seulement de la physique de propagation des ondes mais aussi des caractéristiques de l'acquisition: couplage et orientation des géophones, réponses impulsionnelles des capteurs, bruits.<br /><br /> Après la validation sur des données synthétiques, la nouvelle approche est appliquée sur des données réelles 2D dans le cadre d'une séquence de traitement.<br />Nous montrons que cette approche est robuste en présence de bruit et donne de meilleurs résultats en comparaison avec des séquences standards.<br /><br /> Nous généralisons à la fin de ce document la séquence de traitement au cas des acquisitions OBC 3D grâce à la transformation (Tau,p)3D.<br />Cette généralisation n'est pas immédiate et nécessite des étapes supplémentaires dans la séquence de traitement tel que l'interpolation des données en 3D.<br />La comparaison de la séquence 3D aux séquences standards révèle que la nouvelle approche améliore significativement les résultats

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / The Remote Unit (RU) for a decentralised on-board base-band telemetry system is designed for use in launch vehicle missions of the Indian Space Research Organisation (ISRO). This new design is a highly improved and miniaturised version of an earlier design. The major design highlights are as follows. Usage of CMOS Field Programmable Gate Array (FPGA) technology in place of LS TTL devices, the ability to acquire various types of data like high level single ended or differential analog, bi-level events and two channels of high speed asynchronous serial data from On-Board Computers (OBCs), usage of HMC technology for the reduction of discrete parts etc. The entire system is realised on a single 6 layer MLB and is packaged on a stackable modular frame. This paper discusses the design approach, tools used, simulations carried out, implementation details and the results of detailed qualification tests done on the realised qualification model.

Helicopters are versatile vehicles that can vertically take off and land, hover, and perform maneuver at very low forward speeds. These characteristics make them unique for a number of civilian and military applications. However, the radial and azimuthal variation of dynamic pressure causes rotors to experience adverse phenomena such as transonic shocks and 3-D dynamic stall. Adverse interactions such as blade vortex interaction and rotor-airframe interaction may also occur. These phenomena contribute to noise and vibrations. Finally, in the event of an engine failure, rotorcraft tends to descend at high vertical velocities causing structural damage and loss of lives. A variety of techniques have been proposed for reducing the noise and vibrations. These techniques include on-board control (OBC) devices, individual blade control (IBC), and higher harmonic control (HHC). Addition of these devices adds to the weight, cost, and complexity of the rotor system, and reduces the reliability of operations. Simpler OBC concepts will greatly alleviate these drawbacks and enhance the operating envelope of vehicles. In this study, the use of Gurney flaps is explored as an OBC concept using a physics based approach. A three dimensional Navier-Stokes solver developed by the present investigator is coupled to an existing free wake model of the wake structure. The method is further enhanced for modeling of Blade-Vortex-Interactions (BVI). Loose coupling with an existing comprehensive structural dynamics analysis solver (DYMORE) is implemented for the purpose of rotor trim and modeling of aeroelastic effects. Results are presented for Gurney flaps as an OBC concept for improvements in autorotation, rotor vibration reduction, and BVI characteristics. As a representative rotor, the HART-II model rotor is used. It is found that the Gurney flap increases propulsive force in the driving region while the drag force is increased in the driven region. It is concluded that the deployable Gurney flap may improve autorotation characteristics if deployed only over the driving region. Although the net effect of the increased propulsive and drag force results in a faster descent rate when the trim state is maintained for identical thrust, it is found that permanently deployed Gurney flaps with fixed control settings may be useful in flare operations before landing by increasing thrust and lowering the descent rate. The potential of deployable Gurney flap is demonstrated for rotor vibration reduction. The 4P harmonic of the vertical vibratory load is reduced by 80% or more, while maintaining the trim state. The 4P and 8P harmonic loads are successfully suppressed simultaneously using individually controlled multi-segmented flaps. Finally, simulations aimed at BVI avoidance using deployable Gurney flaps are also presented.

Orientador: Antonio Batocchio / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-11T07:20:48Z (GMT). No. of bitstreams: 1 Fagundes_RenatoAlexandre_M.pdf: 1173048 bytes, checksum: f9c42d8865a1d2718c308d673b82bd20 (MD5) Previous issue date: 2007 / Resumo: Este trabalho tem como objetivo a implementação de um processo cadenciador (ou puxador) na linha de produção de uma indústria fabricante de placas de circuito impresso rígidas, focando principalmente na implantação de um sistema cadenciador para que o fluxo de produção flua de uma maneira cadenciada e limpa para atender uma determinada família de produtos de placas de circuito impresso rígido (não metalizadas ¿simples face¿ e metalizadas ¿dupla face¿). A montagem da célula de produção para o estudo foi desenvolvida a partir da análise da técnica de mapeamento de fluxo estendido para se obter a melhor produtividade do sistema e atender as demandas do cliente final. A existência de algumas formas de variabilidades nos tempos takt, balanceamento de operadores, tempo para troca de modelos e dimensionamento do ciclo de máquinas foram estudadas e apresentadas buscando sempre uma otimização do fluxo contínuo dentro do processo cadenciador. Através das técnicas de mapeamento de fluxo de valor foi montado um mapa de estado atual e futuro o qual nos permite visualizar de uma maneira mais clara as correções propostas. Palavras chaves: Manufatura enxuta, Mapeamento de Fluxo de Valor, Tempo Takt, OBC / Abstract: This work has as objective the implementation of a pacemaker process in the line of production of an industry manufacturer of rigid printed circuit board, where the major is on the implantation of a pacemaker process allowing a production flow clean and smoth for one definitive product family of the printed circuit board (not metallized "single face" and metallized "double face"). The assembly of the cell of production for the study was developed from the analysis of the technique of Mapping Stream Value to get the best productivity of the system and to take care of the demands of the final customer. The existence of some forms of variabilities like : takt time, balancing of operators, time for exchange of models and sizing of the cycle of machines had been studied and presented searching always an optimization of the continuous flow inside of the pacemaker process. Through the techniques of Mapping Stream Value from the current state to future state was mounted which in allows them to visualize in a clear way of the corrections proposals. Key words- Lean Manufacturing, Value Stream Mapping, Takt Time, OBC / Mestrado / Planejamento e Gestão Estrategica da Manufatura / Mestre em Engenharia Mecânica

Bidirectional onboard chargers (OBCs) are becoming mainstream commercial charging equipment for electric vehicles (EVs) because of their compactness, flexibility, and demand-response capabilities for power backup. This thesis focuses on the novel phase shift (PS) modulation techniques for efficiency improvement for bidirectional OBCs, including two-stage onboard chargers (TSOBCs) and single-stage onboard chargers (SSOBCs). A comprehensive overview and investigation of the state-of-the-art solutions of bidirectional OBCs are presented. It reviews the current industrial status, industrial applications, and future trends and challenges. A detailed overview of the promising topologies for bidirectional OBCs, including two-stage and single-stage structures, is also discussed in this thesis. Traditional PS modulation has been widely used in the back-end DC/DC converters of the TSOBCs because of its simple implementation. However, it is challenging to keep high efficiency at boundary operating points within wide specifications. Therefore, to improve efficiency at the boundary point for TSOBCs, the hybrid multiple phase shift (HMPS) modulation technique with minimal peak current optimization is presented to maximize the zero-voltage switching (ZVS) range. Compared to traditional single phase shift (SPS) modulation, the experimental results verify that the presented HMPS modulation strategy provides 1%-2% higher efficiency at the boundary points. On the other hand, an improved compact SSOBC topology and novel PS modulation techniques are proposed. Since the traditional PS modulation is challenging for AC/DC converters to keep a unity power factor (PF), novel PS modulation techniques are presented for the proposed SSOBC. Firstly, a sinusoidal single phase shift (SSPS) modulation introduces a sinusoidal phase shift to maintain a high PF and high efficiency within a wide operating point. However, due to the high current at the zero-crossing point of the grid voltage of the SSPS modulation, the novel adaptive sinusoidal single phase shift (ASSPS) modulation is presented to address this issue, which reduces conduction loss and increases efficiency. Secondly, based on the ASSPS modulation, the adaptive sinusoidal extended phase shift (ASEPS) modulation with minimal peak current optimization is presented to introduce one more degree of freedom to extend the ZVS flexibility, which reduces switching loss. Moreover, the minimal peak current optimization reduces transformer current, further decreasing conduction losses. Therefore, the power loss is minimized. Finally, this thesis presents the general design guideline of a 6 kW Silicon Carbide (SiC)-based bidirectional SSOBC, contributing to the further development of bidirectional SSOBC application. Experimental results verify the operating principle and high PF of the proposed SSPS, ASSPS, and ASEPS modulation. 1 kW experimental testing has validated that the peak efficiency is 95.3% with ASSPS modulation and 95.9% with ASEPS modulation. Compared to the existing pulse width modulation (PWM), the ASSPS modulation increased efficiency by 1.1%, and ASEPS modulation further increased by 1.7%. / Thesis / Doctor of Philosophy (PhD)

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