@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\$N·s e
resolu{\c{c}}{\~a}o m{\'{\i}}nima de 0,05 e m{\'a}xima de
0,10 \$\mu\$N·s, 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\$N·s with a minimum resolution of 0.05
and maximum of 0.10 \$\mu\$N·s, 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/ibi/8JMKD3MGPDW34P/3NMFQ4P",
targetfile = "publicacao.pdf",
urlaccessdate = "27 abr. 2024"
}