Design and Implementation of Attitude Control for 3-axes Magnetic Coil Stabilization of a Spacecraft
Spacecrafts, especially satellites, play an ever greater role
in our daily lives as we increasingly depend on the services they provide,
which in turn, more often than not, critically depend on maintaining
correct payload attitude. As smaller educational satellites pave
the way for organization, group and privately owned pico-satellites, we
explore the possibilities of attitude control through magnetic coil actuation.
We approach the whole problem, from control theory development
to first prototype actualization and control algorithm implementation,
presenting the steps taken in a user-friendly manner while pointing out
the pitfalls and drawbacks of different solutions. The control is based on
a dissipative detumbling controller which after the initial phase is overridden
by the reference controller attaining final desired payload attitude.
We find that a simple 8-bit, 16Mhz microcontroller unit has the su-
cient processing power to continuously compute the geomagnetic field
using the complex International Geomagnetic Reference Field model,
while simultaneously maintaining correct coil actuation. The power
consumed by the controllers during the <300 minute control phase,
from initial tumbling to desired attitude, given a typical tumbling velocity
of absolute magnitude 0.2[rad/sec], is found to be no more than 150
Joules across the randomly selected test scenarios. Thus we are able to
conclude that three perpendicular magnetic coils, together with constantly
present disturbances and complex geomagnetic field model preventing
it from remaining at an ill-aligned attitude where one actuating
degree of freedom is lost, provide sufficient actuation for reference control
of a spacecraft.
Place, publisher, year, edition, pages
Institutt for teknisk kybernetikk , 2011. , 144 p.
ntnudaim:5920, MTTK teknisk kybernetikk, Reguleringsteknikk
IdentifiersURN: urn:nbn:no:ntnu:diva-13273Local ID: ntnudaim:5920OAI: oai:DiVA.org:ntnu-13273DiVA: diva2:436730
Gravdahl, Jan Tommy, Professor