Περίληψη:
This paper addresses the problem of singularity avoidance in a cluster
of four Single-Gimbal Control Moment Gyroscopes (SGCMGs) in a pyramid
configuration when used for the attitude control of a satellite by
introducing a new gimballed control moment gyroscope (GCMG) cluster
scheme. Four SGCMGs were used in a pyramid configuration, along with an
additional small and simple stepper motor that was used to gimbal the
full cluster around its vertical (z) axis. Contrary to the use of four
variable-speed control moment gyroscopes (VSCMGs), where eight degrees
of freedom are available for singularity avoidance, the proposed GCMG
design uses only five degrees of freedom (DoFs), and a modified steering
law was designed for the new setup. The proposed design offers the
advantages of SGCMGs, such as a low weight, size, and reduced
complexity, with the additional benefit of overcoming the internal
elliptic singularities, which create a minor attitude error. A
comparison with the four-VSCMG cluster was conducted through numerical
simulations, and the results indicated that the GCMG design was
considerably more efficient in terms of power while achieving a better
gimbal configuration at the end of the simulation, which is essential
when it is desired for different manoeuvres to be consecutively
executed. Additionally, for a nano-satellite of a few kilograms, the
results prove that it is feasible to manufacture the GCMG concept by
using affordable and lightweight commercial off-the-shelf (COTS) stepper
motors.
Συγγραφείς:
Papakonstantinou, Charalampos
Lappas, Vaios
Kostopoulos,
Vassilis
