Magnetocoulombic Attitude Control of Earth-Pointing Satellites

A magnetocoulombic satellite system is proposed and equations are developed to study the stability and control characteristics for a set of given initial conditions. An equation for charge required on coulomb shells is derived, which is used to find the available torque for actuating the satellite. It is shown that this system is similar to a satellite actuated by magnetic coils, except that the available torque vanishes for two different conditions. Controllability of the magnetocoulombic satellite rotating at a high angular velocity is proved. Moreover, stability is proved for a very high initial angular velocity, in addition to its exponential stability in the neighborhood of the origin. It is proved that the eigenvalues of the average control matrix, corresponding to different orientations and angular velocities of the satellite, in the body reference frame will converge to the same values as time tends to infinity. Moreover, it is proved that the eigenvalues of the average control matrix in the body reference frame will be equal to the corresponding eigenvalues in the orbital reference frame. Simulations are carried out for various initial orientations and angular velocities, to show the efficacy of the proposed magnetocoulombic system for controlling the global attitude and the angular velocity of the satellite. A comprehensive physical analysis of the system dynamics is presented.