Slew maneuver control for spacecraft equipped with star camera and reaction wheels

A configuration consisting of a star camera, four reaction wheels and magnetorquers for momentum unloading has become standard for many spacecraft missions. This popularity has motivated numerous agencies and private companies to initiate work on the design of an imbedded attitude control system realized on an integrated circuit. This paper provides an easily implementable control algorithm for this type of configuration. The work considers two issues: slew maneuver with a feature of avoiding direct exposure of the camera's CCD chip to the Sun and optimal control torque distribution in a reaction wheel assembly. The attitude controller is synthesized applying the energy shaping technique, where the desired potential function is carefully designed using a physical insight into the nature of the problem. A detailed simulation study shows convincing results for the entire range of operation.