Citation: Posani, M.; Pontani, M.;
Gasbarri, P. Nonlinear Slewing
Control of a Large Flexible Spacecraft
Using Reaction Wheels. Aerospace
2022, 9, 244. https://doi.org/
10.3390/aerospace9050244
Academic Editors: Mikhail
Ovchinnikov and Dmitry Roldugin
Received: 27 January 2022
Accepted: 21 April 2022
Published: 26 April 2022
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Article
Nonlinear Slewing Control of a Large Flexible Spacecraft Using
Reaction Wheels
Massimo Posani
1,
*, Mauro Pontani
2
and Paolo Gasbarri
3
1
Faculty of Civil and Industrial Engineering, Sapienza Università di Roma, Via Eudossiana 18,
00186 Rome, Italy
2
Department of Astronautical, Electrical, and Energy Engineering, Sapienza Università di Roma,
Via Salaria 851, 00138 Rome, Italy; mauro.pontani@uniroma1.it
3
School of Aerospace Engineering, Sapienza Università di Roma, Via Salaria 851, 00138 Rome, Italy;
paolo.gasbarri@uniroma1.it
* Correspondence: posani.1694020@studenti.uniroma1.it
Abstract:
Reorientation maneuvers represent a key task for large satellites. This work considers a
space vehicle with solar panels and reaction wheels as actuation devices. Solar panels are modeled
as flexural beams, using the modal decomposition technique. An inertia-free nonlinear attitude
control algorithm, which enjoys quasi-global stability properties, is employed for the numerical
simulation of a large reorientation maneuver. Preliminary analysis with ideal actuation allows sizing
the control system and identifying the expected elastic displacements. Then, the actuation dynamics
is included, and the actual torque transferred to the vehicle no longer coincides with the commanded
one, supplied by the nonlinear control algorithm. Moreover, the solar panels are designed to rotate,
in order to maximize the power storage during the maneuver. The numerical results prove that the
slewing maneuver is successfully completed in reasonable time and without any saturation of the
actuation devices, while the elastic displacements remain modest, in spite of the solar panel rotation
aimed at pursuing the Sun direction.
Keywords:
slewing maneuvers; multibody space systems; elastic dynamics; reaction wheels; nonlin-
ear attitude control; solar panel dynamics
1. Introduction
Attitude slewing maneuvers represent a common task for spacecraft that orbit the
Earth or other celestial bodies. Specifically, these maneuvers are continuously performed
by large satellites dedicated to the space observation, such as the Hubble Space Telescope.
The design, implementation, and testing of effective attitude control algorithms is an active
research area, with the final objective of identifying suitable feedback schemes, effective
and accurate for autonomous attitude control.
Different representations for attitude kinematics are available. Euler angles require
only three quantities to identify the spacecraft orientation in space. However, they are usu-
ally avoided due to the well-known singularity issues associated with this representation.
Euler parameters (quaternions) avoid these singularities and are suitable for describing
large reorientation maneuvers. Several contributions in the scientific literature employed
the Euler parameters (quaternions) as the kinematics variables [
1
–
3
]. The final goal was in
identifying fedback control laws that enjoy quasi-global stability properties. Their main
drawback is represented by the need for accurate knowledge of the spacecraft mass distribu-
tion, in particular its instantaneous inertia matrix. This information may not be sufficiently
accurate, and this circumstance can compromise the pointing maneuver or reduce its
precision. Recently, some inertia-free algorithms were proposed that do not require any
accurate knowledge of the spacecraft mass distribution [
4
,
5
]. In particular, Sanyal et al. [
4
]
Aerospace 2022, 9, 244. https://doi.org/10.3390/aerospace9050244 https://www.mdpi.com/journal/aerospace
