Concepção Modular de Dispositivos Electrónicos

Ao longo deste trabalho são abordados temas relacionados com a concepção modular de dispositivos electrónicos. Esta temática tem sido alvo de diversos trabalhos de investigação a nível mundial, mas grande parte das conclusões são ainda muito dependentes do ponto de vista pessoal dos investigadores. Assim, numa primeira abordagem, são apresentadas algumas das classificações e características da concepção modular de produtos e as principais vantagens e desvantagens desta metodologia relativamente à concepção integral de produtos, isto do ponto de vista geral dos produtos e não restrito aos dispositivos electrónicos, apesar de estes serem usados regularmente nos exemplos devido à temática deste trabalho. Posteriormente é referida uma possível implementação de um dispositivo electrónico modular composto por três módulos diferentes, nomeadamente uma fonte de alimentação comutável, uma interface com o utilizador e um sistema de comunicação sem fios. Estes módulos são dimensionados e caracterizados de forma a serem algo genéricos na sua implementação, sendo igualmente destacadas temáticas de investigação relacionadas com as tecnologias utilizadas em cada um dos módulos ou os seus sistemas concorrentes. Algumas das funções possíveis dos dois últimos módulos são ainda demonstradas recorrendo a dispositivos de prototipagem rápida que incluem a plataforma mbed NXP LPC1768.Throughout this work themes related to the modular design of electronic devices are adressed. This theme has been the subject of several worldwide researches, but most of the findings are still very dependent on the personal standpoint of each researcher. In a first approach, some of the classifications and characteristics of the modular design of products and the main advantages and disadvantages of this method relative to the integral design of products are presented, although initially through a general view of products and not a view restricted to electronic devices, even though these are regularly used in the examples due to the theme of this work. Subsequently it is referred a possible implementation of a modular electronic device composed of three different modules, including a switch mode power supply, a user interface and a wireless communication system. These modules are designed and characterized in order to be something generic in its implementation and some research related with the technology in use in the modules or its competitors is presented in the correspondent chapters. Some possible functions of the last two modules are further demonstrated using rapid prototyping devices that include the mbed NXP LPC1768 platform

Viking '75 spacecraft design and test summary. Volume 2: Orbiter design

The design of the Viking orbiter spacecraft is described. System configuration, telecommunications, and guidance and control requirements are presented

Digital Control of LFSW HID Lamp Drivers with Soft Saturation Magnetic Materials and Integrated Resonant Lamp Ignition

Electronic HID ballasts provide many advantages over magnetic HID ballasts including size, weight, overall efficiency, and greater control of operating conditions. Electronic ballasts add complexity to the system, requiring a greater understanding of the operation of HID lamps. Electronic ballasts also introduce a host of issues for the HID ballast designer including possible acoustic resonances, arc stability issues, and operation across broad operating conditions. In this work, research of a Low-Frequency Square-Wave (LFSW) HID solution is performed that includes use of a non-linear soft saturation core material for the inductor. Modeling of the converter with this core is presented as well. Difficulties with operation of HID lamps are outlined, as well as the previous methods to overcome such obstacles. Ignition and steady-state operation of HID lamps occur with very different operating conditions. Ignition occurs with very little lamp current, but large lamp voltage, and steady-state operation is the opposite. Due to this mismatch, any single ignitor/ballast design requires the inductor to be able to handle both operating points. Use of a soft saturation material allows for a reduction in size and weight of the overall system due to the higher magnetic capacity of the material as compared to hard saturation alternatives. The downside to using this material is inductance varies with magnetizing force on the core. A resonant ignition approach with soft saturation material is presented, motivating the need for phase control of the system. A fast transition between resonant and LFSW mode operation is presented, which requires a large design space for possible lamp impedances. Transition times between LFSW modes are dependent on natural frequency and Q factor of a buck filter response, which is shaped beneficially by the soft saturation material. A design method for this is presented, along with considerations for core selection. A two loop control method is analyzed with an inner current loop that stabilizes the lamp arc and an outer power loop in order to obtain regulated light output. The current loop is able to monitor currents of a positive and negative buck mode operation using a single sense point. A system that uses input power sensing to ultimately control output power is analyzed and experimentation is presented

The 20th Aerospace Mechanisms Symposium

Numerous topics related to aerospace mechanisms were discussed. Deployable structures, electromagnetic devices, tribology, hydraulic actuators, positioning mechanisms, electric motors, communication satellite instruments, redundancy, lubricants, bearings, space stations, rotating joints, and teleoperators are among the topics covered