Investigating the “inverted attitude” problem in a spacecraft stabilisation system featuring non-linear sensors

Abstract

The paper shows that gravitational torque may cause an emergency “inverted attitude” mode in a relay spacecraft stabilisation system due to the fact that a field-of-view limit type sensor may be non-linear. We performed structural partitioning of the phase cylinder into regions with various trajectory types for the case of a simplified planar motion model. We demonstrate the synthesis routine for finding the boundaries separating the region marking the system transitioning into the regular attitude mode from the region signifying it entering the emergency mode. We derived analytical conditions under which emergency modes arise, which can serve as the basis for synthesising algorithms to prevent these modes from occurring.