Stochastic control of pitch motion of satellites using stabilizing flaps

The modelling, analysis and synthesis of an attitude control system for low orbit artificial satellites using stabilizing flaps are presented. The function of the system is to maintain the satellite aligned with the local vertical. The aerodynamic forces on the satellite are modelled assuming free molecular flow using the kinetic theory of gases. The control system development is considered through the application of stochastic control concepts. The satellite motion is described by the equations of motion based on Newtonian formulation. Starting from the separation principle, a sequential procedure is developed in which the state estimation and control problems are handled simultaneously. State estimate is provided by Kalman filter using the information about the position of the satellite and of the flaps. The controller acts on satellite in real time, and the stabilizing flaps are the only control elements.