CC BY
14Малые космические аппараты: производство, эксплуатация и управление
UDK 669.713.7
ESTIMATION OF A MAGNETIC DISTURBANCE TORQUE CAUSED BY FERROMAGNETIC MATERIALS IN SMALL SATELLITES
Takaya Inamori, Phongsatorn Saisutjarit, Hiroyuki Ohsaki The University of Tokyo, Japan, Tokyo
This research analyses a magnetic disturbance torque caused by the interaction between the geomagnetic field and ferromagnetic materials in a satellite. This research also proposes a new method to estimate the magnetic disturbance caused by ferromagnetic materials for precise attitude control in small satellites.
Keywords: Low earth orbit satellites, Attitude disturbance, Magnetic substances, State estimation, Attitude estimation.
Small satellites attract interest as an easily achievable space application because of their relatively cheaper development cost and shorter development period. These small satellites are used in various mission applications such as remote sensing and astronomical observation that require precise attitude control. To achieve the precise attitude control, effects of attitude disturbances should be cancelled during the missions. Small-satellites in LEO suffer from various attitude disturbances such as magnetic disturbance, air pressure disturbance, solar disturbance, and gravity gradient disturbance. In standard-sized satellites, the effect of magnetic disturbance is insignificant and therefore not considered in previous researches. However, in small satellites, magnetic disturbance is the dominant attitude disturbance. This is because the magnetic moment has a relatively strong effect on such satellites owing to their small moment of inertia (Inamori et al., 2011). To satisfy the strict attitude requirements for small-satellites in LEO, the effect of magnetic disturbance should be mitigated to achieve precise attitude control. Figure 1 shows the effect of a magnetic disturbance in previous satellite missions. The horizontal and vertical axes show the satellite moment of inertia and the angular acceleration due to a magnetic field produced by magnetic disturbance, respectively. Figure shows that magnetic disturbance has a larger effect in smaller satellites. Therefore, this effect should be well understood in small satellites.
This research considers a disturbance torque caused by ferromagnetic materials in a satellite. In previous works, the effect of the ferromagnetic materials causing a
disturbance torque in the geomagnetic field is not considered for the precise attitude control.
Relationship between satellite mass and residual magnetic moment of a satellite. (Inamori et al., 2011)
The ferromagnetic materials such as iron cores of MTQs and a magnetic hysteresis damper for a passive attitude control system is used in various small satellite missions. These materials cause a disturbance torque which is almost the same magnitude of the dipole magnetic disturbance in the worst cases. This research proposes an estimation method of the disturbance torque caused by the ferromagnetic materials using the extended Kalman filter. The research concludes that the proposed method is useful for precise attitude control for small satellite missions from simulation results.
© Takaya Inamori, Phongsatorn Saisutjarit, Hiroyuki Ohsaki, 2013
УДК 629.7.054.847
МОДЕЛИРОВАНИЕ ДИНАМИКИ ЭЛЕКТРОДВИГАТЕЛЯ-МАХОВИКА С УЧЕТОМ ТЕХНОЛОГИЧЕСКИХ ПОГРЕШНОСТЕЙ
А. А. Васильцов
ОАО «Научно-производственный центр «Полюс» Россия, 634050, г. Томск, просп. Кирова, 56, в. E-mail: POLUS@ONLINE.TOMSK.NET
Рассмотрена методика определения возмущающих моментов, порождаемых технологическими погрешностями электродвигателя-маховика и действующих на космический аппарат. Выявлены конструктивные и технологические факторы, влияющие на значение данных моментов.
Ключевые слова: двигатель-маховик, возмущающие моменты.
