Modeling of a stratospheric satellite and the orbit control based on hierarchical models

To implement the flight of stratospheric satellites along latitudinal orbits in atmospheric circulation, the longitudinal trajectories of the stratospheric satellite must be controlled. First, the 6-DOF dynamic model of a stratospheric satellite is established based on the Lagrange dynamic formulation for the longitudinal trajectory control design. Because the input/output linearization method is not applicable to this model, the whole system is decomposed into three cascaded subsystems based on the flight-control mechanism of the satellite, i.e. the rudder controls the stratosail, the stratosail supports the tether, and the tether drags the balloon; and then, three separate controllers are developed for each subsystems to achieve the trajectory control of the balloon via the rudder. Simulation results demonstrate the effectiveness of the proposed controllers.