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

Aerospace ◽  
2019 ◽  
Vol 6 (12) ◽  
pp. 133 ◽  
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.

scholarly journals Modelling the attitude dynamics of small spacecraft with a magnetic attitude control system in three-axis stabilization mode

2019 ◽  
Vol 488 (4) ◽  
pp. 377-382
Author(s):  
V. M. Kulkov ◽  
Yu. G. Egorov ◽  
S. O. Firsyuk ◽  
V. V. Terentyev ◽  
A. O. Shemyakov
Keyword(s):  
Magnetic Field ◽  
Mathematical Model ◽  
Control System ◽  
Attitude Control ◽  
Control Law ◽  
Attitude Dynamics ◽  
Attitude Control System ◽  
Small Spacecraft ◽  
Magnetic Attitude Control ◽  
System Movement

The problem of modeling the attitude-control modes of small spacecraft with the use of electromagnetic systems, interacting with the Earths magnetic field is considered. A small spacecraft angular motion mathematical model is developed. A control law for magnetic attitude control system of small spacecraft is formulated. Results of satellite with magnetic attitude control system movement numerical modelling are presented.

“The heart above the ruins”: Miriam Waddington’s Poetry, the Spanish Civil War, and Jewish Canadian Literature

1969 ◽  
Vol 26 ◽  
Author(s):  
Emily Robins Sharpe
Keyword(s):  
Human Rights ◽  
World War Ii ◽  
Civil War ◽  
Spanish Civil War ◽  
World War ◽  
Canadian Literature ◽  
The Earth ◽  
The Holocaust ◽  
The Subject ◽  
War Consequences

The Jewish Canadian writer Miriam Waddington returned repeatedly to the subject of the Spanish Civil War, searching for hope amid the ruins of Spanish democracy. The conflict, a prelude to World War II, inspired an outpouring of literature and volunteerism. My paper argues for Waddington’s unique poetic perspective, in which she represents the Holocaust as the Spanish Civil War’s outgrowth while highlighting the deeply personal repercussions of the war – consequences for women, for the earth, and for community. Waddington’s poetry connects women’s rights to human rights, Canadian peace to European war, and Jewish persecution to Spanish carnage.

Two-timescale magnetic attitude control of Low-Earth-Orbit spacecraft

2021 ◽  
pp. 106884
Author(s):  
Giulio Avanzini ◽  
Emanuele L. de Angelis ◽  
Fabrizio Giulietti
Keyword(s):  
Attitude Control ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Magnetic Attitude Control

Boundary control design based on partial differential equation observer for vibration suppression and attitude control of flexible satellites with multi-section solar panels

2021 ◽  
pp. 107754632199015
Author(s):  
Mohammad Mahdi Ataei ◽  
Hassan Salarieh ◽  
Hossein Nejat Pishkenari ◽  
Hadi Jalili
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Attitude Control ◽  
Vibration Suppression ◽  
Equation System ◽  
Solar Panels ◽  
Attitude Dynamics ◽  
Partial Differential ◽  
Satellite Attitude ◽  
Element Technique

A novel partial differential equation observer is proposed to be used in boundary attitude and vibration control of flexible satellites. Solar panels’ vibrations and attitude dynamics form a coupled partial differential equation–ordinary differential equation system which is controlled directly without discretization. Few feedback signals from boundaries are required which are estimated via a partial differential equation observer. Consequently, just satellite attitude and angular velocity should be measured and still the control system benefits information from continuous part vibrations. The closed-loop system is proved to be asymptotically stable. Simulations with a finite element technique illustrate good performance of this observer-based boundary controller.

scholarly journals Fully magnetic attitude control subsystem for picosat platforms

2018 ◽  
Vol 62 (12) ◽  
pp. 3383-3397 ◽  
Author(s):  
Andrea Colagrossi ◽  
Michèle Lavagna
Keyword(s):  
Attitude Control ◽  
Control Subsystem ◽  
Magnetic Attitude Control

scholarly journals V.—Further Excavations at Lanuvium

Archaeologia ◽  
1892 ◽  
Vol 53 (1) ◽  
pp. 147-154
Author(s):  
Lord Savile
Keyword(s):  
The Earth ◽  
The Subject

Since the last communication on the subject of my excavations at Lanuvium, which the Society of Antiquaries did me the honour to publish in 1886, those excavations have been carried on continuously, but very slowly, in consequence of the difficulties arising from the necessity of devising some means for disposing of the earth extracted in the course of excavation.

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