Model predictive control of low earth orbiting spacecraft with magneto-torquers

The problem of attitude control using magnetic torque rods is addressed, in order to demonstrate predictive control as a suitable and effective technique of magnetic attitude control. The study addresses the key issues of magnetic field modeling, controller stability and implementation. Two controller designs are implemented, the first adopting an MPC approach with a constant magnetic field assumption, while the second method includes the true variation of the magnetic field within the control law. Both methods demonstrate significantly improved performance over PD control with the inclusion of the true magnetic field variation leading to the best results. Controller stability is considered with and without terminal penalty within the cost function. Floquet analysis demonstrates both methods to be stable, however the terminal penalty based method leads to a more stable controller.