Abstract:

As the initial flight phase of reusable launch vehicle (RLV), the ascending phase has its special characteristics, that is, fast changes during flight in the gravity center, the atmospheric density and the motion state. The control law should suit the fine stability and maneuverability in the whole flight envelope to make analysis easy. The entire flight is divided into four phases in this paper: drop, ignition, powered climb and unpowered climb. Different control strategies are used according to the characteristic of each phase. Trajectory linearization control (TLC) is involved for advanced nonlinear tracking and robust control, and the forward control and feedback control law are designed. Nonlinear simulation shows that the control scheme satisfies the ascent control requirements.

Key words: reusable launch vehicle, ascent, trajectory linearization, flight control, nonlinear simulation