Stabilization of the Solar Orientation Mode of an Artificial Earth Satellite by an Electromagnetic Control System

Resumo

The solar orientation mode of an artificial Earth satellite is investigated. Satellite parameters correspond to the parameters of the Bion M and Foton M-4 satellites. In this mode, the normal to the satellite solar cell plane is always directed to the Sun, the longitudinal axis lies in the plane of the orbit, and the satellite absolute angular velocity is very small. The mode is stabilized by electromagnets that interact with the Earth magnetic field and a rotating flywheel that generates a constant gyrostatic moment along the satellite longitudinal axis. Such a moment can be generated using a reaction wheel system. The constancy of the gyrostatic moment means that this system will operate without saturation. The satellite attitude control is implemented by changing the currents in the electromagnets. Two control laws that reduce the satellite angular velocity and stabilize the solar orientation are investigated. Their implementation does not require complex measurements. It is sufficient to have the readings of a solar sensor and a triaxial magnetometer and equipment for their processing. The effectiveness of control laws is confirmed by the mathematical modeling of the satellite motion with respect to the center of mass under the influence of gravitational and aerodynamic moments, as well as the moment generated by electromagnets.