Attitude Control of High Area-to-mass Ratio (HAMR) Spacecrafts Considering the Eclipse by the Earth

In this work, we study the effects of solar radiation pressure (SRP) on the problem of changing the orbit of an asteroid to support planetary defense, scientific research, or exploitation of materials. This alternative considers a tethered reflective balloon (or a set of reflective balloons) attached to the asteroid, with a high area-to-mass ratio, to use the SRP to deflect a potentially hazardous asteroid (PHA) or to approximate the target asteroid to Earth. The tether is assumed to be inextensible and massless, and the motion is described only in the orbital plane of the asteroid around the Sun. The model is then used to study the effects that the tether length, the reflectivity coefficient, and the area-to-mass ratio have on the deviation of the trajectory of the asteroid.

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Implementation and Hardware-In-The-Loop Simulation of a Magnetic Detumbling and Pointing Control Based on Three-Axis Magnetometer Data

Aerospace ◽

10.3390/aerospace6120133 ◽

2019 ◽

Vol 6 (12) ◽

pp. 133 ◽

Cited By ~ 2

Author(s):

M. Salim Farissi ◽

Stefano Carletta ◽

Augusto Nascetti ◽

Paolo Teofilatto

Keyword(s):

Attitude Control ◽

Experimental Testing ◽

Hardware In The Loop ◽

Attitude Dynamics ◽

The Earth ◽

Earth Magnetic Field ◽

Magnetic Attitude Control ◽

Magnetometer Data ◽

The Subject ◽

Pointing Control

The subject of this work is the implementation and experimental testing of a purely magnetic attitude control strategy, which can provide stabilization after the deployment and pointing of the spacecraft without any attitude information. In particular, the control produces the detumbling of the satellite and leads it to a desired attitude with respect to the direction of the Earth magnetic field, based on the only information provided by a three-axis magnetometer. The system is meant to be used as a backup solution, in case of failure of the primary strategy and is designed considering the constraints set on time of operations, power consumption, and peak electric current for a typical CubeSat mission. The detumbling and pointing algorithms are implemented on the FPGA core of a CubeSat on-board computer and tested by Hardware-in-the-loop simulations. The simulation setup includes a Helmholtz cage, recreating the magnetic environment along the orbit, the on-board computer, a MEMS three-axis magnetometer and Simulink software, on which the attitude dynamics is propagated. Test on the real system can provide useful information to select the parameters of the control, such as the gains, to estimate the limits of the system, the time of operations and prevent failures.

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A New Fabrication Process for Microstructures With High Area-to-Mass Ratios by Stiffness Enhancement

Volume 4: 23rd Design for Manufacturing and the Life Cycle Conference; 12th International Conference on Micro- and Nanosystems ◽

10.1115/detc2018-86282 ◽

2018 ◽

Cited By ~ 5

Author(s):

Zhongjing Ren ◽

Jianping Yuan ◽

Xiaoyu Su ◽

Hao Sun ◽

Richard Galos ◽

...

Keyword(s):

Joule Heating ◽

Mechanical Systems ◽

Silicon Layer ◽

Fabrication Process ◽

Structural Parameter ◽

Mass Ratio ◽

Micro Electro Mechanical Systems ◽

Thickness Increase ◽

High Area ◽

Mass Ratios

A new fabrication process for stiffness-enhanced microstructures with high area-to-mass ratios is presented in this paper. In order to acquire an enhanced stiffness without ruining the structural parameter of area-to-mass ratio, multilayered metallic microstructures are proposed and fabricated by surface and bulk fabrication processes from Micro-Electro-Mechanical Systems (MEMS) technologies. Microstructures based on beams with symmetrically deposited metals are physically built and tested on wafers. A sacrificial silicon layer is used to form gaps between bimetal layers and the microstructures can be deployed vertically when heated due to the effect of thermal mismatch between different materials. The results show a dramatic thickness increase when actuated by Joule heating, and thus a great bending stiffness enhancement.

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Instrument observation strategy for a new generation of three-axis-stabilized geostationary meteorological satellites from China

Geoscientific Instrumentation Methods and Data Systems ◽

10.5194/gi-8-161-2019 ◽

2019 ◽

Vol 8 (2) ◽

pp. 161-175

Author(s):

Jian Shang ◽

Lei Yang ◽

Pan Huang ◽

Huizhi Yang ◽

Chengbao Liu ◽

...

Keyword(s):

Attitude Control ◽

Mode Design ◽

The Earth ◽

Observation Strategy ◽

Ground System ◽

Image Navigation ◽

Complicated Part ◽

New Generation ◽

Observation Strategies ◽

Instrument Observation

Abstract. The Fengyun-4 (FY-4) satellite series is a new generation of geostationary meteorological satellites from China. The newly adopted three-axis-stabilized attitude-control platform can increase observation efficiency and flexibility while bringing great challenges for image navigation as well as integrated observation mode design. Considering the requirements of earth observation, navigation and calibration as well as observation flexibility, instrument observation strategies are proposed. These include the earth, the moon, stars, cold space, blackbody and diffuser observations on which the instruments' in-orbit daily observations must be based. The most complicated part is the star observation strategy, while navigation precision is dependent on in-orbit star observations. A flexible, effective, stable and automatic star observation strategy directly influences star data acquisition and navigation precision. According to the requirement of navigation, two specific star observation strategies for the two main instruments on board FY-4A were proposed to be used in the operational ground system. The strategies have been successfully used in FY-4A in-orbit tests for more than a year. Both the simulation results and in-orbit application results are given, including instrument observation strategies, star observation strategies and moon observation tasks, to demonstrate the validity of the proposed observation strategies, which lay important foundations for the instruments' daily operation.

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Automatic control of the microaerial vehicles’ attitude and position

International Journal of Micro Air Vehicles ◽

10.1177/1756829316673847 ◽

2016 ◽

Vol 9 (1) ◽

pp. 61-73 ◽

Cited By ~ 1

Author(s):

Romulus Lungu ◽

Mihai Lungu

Keyword(s):

Attitude Control ◽

Lyapunov Theory ◽

Control Law ◽

Nonlinear Dynamic Model ◽

Damping Coefficients ◽

Microaerial Vehicles ◽

The Earth ◽

Dynamic Damping ◽

Dynamic Compensator ◽

Automatic Systems

The paper focuses on two automatic systems for the attitude and position’s control of the microaerial vehicles—insect type by using a nonlinear dynamic model, which describes the motion of microaerial vehicles with respect to the Earth tied frame. The attitude control is adaptive type, with the estimation of the inertia moments’ matrix and of the dynamic damping coefficients’ matrix in two variants: by means of the attitude vector or by using the quaternion vector. The new resulting control architectures use a vector for the control of the microaerial vehicles’ attitude, a proportional-derivative linear dynamic compensator, an error vector (whose elements are the estimated deviations of the inertia moments and dynamic damping coefficients with respect to the real ones), and the Lyapunov theory. In the two variants of the adaptive control, the control law is represented by the command aerodynamic moments and the wing rotation’s command vector, respectively; the control law for the microaerial vehicle position’s control is deduced in the same way. The two obtained control systems are validated by complex numerical simulations.

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