Satellite control by stabilizing flaps

The modelling and analysis of the 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. For this purpose, the control system utilizes the aerodynamic forces acting on the flaps which create the restoring torques reorienting the satellite in line 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 contol concepts. The satellite motion is described by the equations of motion based on Newtonian formulation. Starting from 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 by using the information about the position of the satellite and of the flaps. The controller acts on the satellite in real time, and the stabilizing flaps being the only control elements.