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@MastersThesis{Anselmo:2017:DeBaEm,
               author = "Anselmo, Marcelo Renato",
                title = "Desenvolvimento de uma balan{\c{c}}a de empuxo para propulsores 
                         el{\'e}tricos",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2017",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2017-03-30",
             keywords = "balan{\c{c}}a de empuxo, PPT, DCE, impulso, empuxo, thrust 
                         balance, PPT, DCE, impulse bit, thrust.",
             abstract = "Os testes de caracteriza{\c{c}}{\~a}o de propulsores buscam a 
                         obten{\c{c}}{\~a}o de par{\^a}metros de desempenho, tais como 
                         empuxo, impulso e impulso espec{\'{\i}}fico. Para isto, foi 
                         desenvolvida uma balan{\c{c}}a de empuxo para propulsores de 
                         plasma pulsado (PPTs, Pulsed Plasma Thrusters), com faixa de 
                         medi{\c{c}}{\~a}o de impulso entre 14 e 79 \$\mu\$NĚs e 
                         resolu{\c{c}}{\~a}o m{\'{\i}}nima de 0,05 e m{\'a}xima de 
                         0,10 \$\mu\$NĚs, necess{\'a}ria para a 
                         caracteriza{\c{c}}{\~a}o inequ{\'{\i}}voca destes propulsores 
                         el{\'e}tricos. A t{\'e}cnica de medi{\c{c}}{\~a}o direta, na 
                         qual o propulsor {\'e} montado sobre a balan{\c{c}}a de empuxo, 
                         {\'e} considerada a mais adequada e precisa para 
                         aplica{\c{c}}{\~o}es com PPTs, permitindo a medi{\c{c}}{\~a}o 
                         de baixos valores de empuxo (\$\sim\$ 1 \$\mu\$N). A 
                         balan{\c{c}}a de empuxo pode ter a configura{\c{c}}{\~a}o de um 
                         p{\^e}ndulo de suspens{\~a}o, p{\^e}ndulo invertido ou 
                         p{\^e}ndulo de tor{\c{c}}{\~a}o. A configura{\c{c}}{\~a}o de 
                         p{\^e}ndulo de tor{\c{c}}{\~a}o foi utilizada devido {\`a}s 
                         suas principais vantagens como relativa simplicidade de 
                         constru{\c{c}}{\~a}o e custo reduzido. Al{\'e}m disso, essa 
                         configura{\c{c}}{\~a}o permite que a for{\c{c}}a de 
                         restaura{\c{c}}{\~a}o da balan{\c{c}}a de empuxo seja 
                         independente da massa do propulsor, pois seu eixo de 
                         rota{\c{c}}{\~a}o {\'e} paralelo ao vetor da for{\c{c}}a 
                         gravitacional. O uso de piv{\^o}s de tor{\c{c}}{\~a}o de baixa 
                         rigidez fez com que a balan{\c{c}}a pudesse ser mais compacta, 
                         com um bra{\c{c}}o de tor{\c{c}}{\~a}o menor. Um dispositivo de 
                         calibra{\c{c}}{\~a}o eletrost{\'a}tica foi projetado e 
                         constru{\'{\i}}do para simular o empuxo de PPTs, calibrar a 
                         balan{\c{c}}a de empuxo e permitir futuros testes da 
                         balan{\c{c}}a com propulsores de plasma pulsado de dupla descarga 
                         (DD-PPT, Double Discharge Pulsed Plasma Thrusters), desenvolvidos 
                         no Laborat{\'o}rio Associado de Combust{\~a}o e Propuls{\~a}o 
                         do Instituto Nacional de Pesquisas Espaciais. A balan{\c{c}}a 
                         projetada apresentou um erro m{\'a}ximo na medi{\c{c}}{\~a}o de 
                         impulso de 10 \%, abaixo da faixa de valores de 12 a 15 \%, 
                         t{\'{\i}}picos para este tipo de balan{\c{c}}a de empuxo. 
                         ABSTRACT: The thrusters characterization tests seek to obtain the 
                         performance parameters such as thrust, impulse bit and specific 
                         impulse. For this, a thrust balance for pulsed plasma thrusters 
                         (PPTs) has been developed, able to measure impulse bit values 
                         between 14 and 79 \$\mu\$NĚs with a minimum resolution of 0.05 
                         and maximum of 0.10 \$\mu\$NĚs, necessary for the unambiguous 
                         characterization of these electric thrusters. The direct 
                         measurement technique, in which the thruster is mounted on the 
                         thrust balance, is considered the most suitable and accurate for 
                         applications with PPTs, allowing the measurement of low thrust 
                         values (\$\sim\$ 1 \$\mu\$N). The thrust balance can be 
                         configured as a hanging pendulum, inverted pendulum or torsional 
                         pendulum. The torsional pendulum configuration has as main 
                         advantages the relative construction simplicity and reduced cost. 
                         In addition, this configuration allows the thrust balance 
                         restoration force to be independent of the mass of the thruster, 
                         since its rotation axis is parallel to the gravitational force 
                         vector. The use of flexural pivots which have low stiffness makes 
                         the balance more compact, with a smaller torsional arm. An 
                         electrostatic calibration device was designed and built to 
                         simulate the thrust of PPTs, to calibrate the thrust balance and 
                         to allows forthcoming tests using double discharge pulsed plasma 
                         thrusters developed in the Associated Laboratory of Combustion and 
                         Propulsion of the Brazilian National Institute for Space Research. 
                         The maximum impulse bit measurement error provided by the balance 
                         designed was 10 \%, lower than the value range of 12 to 15 \%, 
                         typical for this type of thrust balance.",
            committee = "Marques, Rodrigo Intini (presidente) and Sandonato, Gilberto 
                         Marrega (orientador) and Costa, Fernando de Souza and Gessini, 
                         Paolo",
         englishtitle = "Development of a thrust balance for electric thrusters",
             language = "pt",
                pages = "177",
                  ibi = "8JMKD3MGPDW34P/3NMFQ4P",
                  url = "http://urlib.net/rep/8JMKD3MGPDW34P/3NMFQ4P",
           targetfile = "publicacao.pdf",
        urlaccessdate = "04 dez. 2020"
}


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