Stability control for mass center mutation of a post-boost vehicle

For a post-boost vehicle, the mathematic model of attitude system was established using the unitary quaternions. The variations of the inertia matrix and the position of the mass center caused by the separation of the warehouse and warheads were characterized in detail. A nonlinear feedback controller, which can globally asymptotically stabilize the closed-loop system, was proposed based on the Lyapunov approach. Specially, the time-varying characteristic and uncertainties of the inertia matrix were taken into consideration and corresponding controllers were brought forward. The controller proposed was applied to a post-boost vehicle. Nonlinear simulations were carried out for the process of large angle maneuver and the separation of the warehouse and warheads. The results show that the controller designed can successfully stabilize the attitude system during the angle maneuver and separation process. The attitude variables change smoothly on the whole trajectory and the constraints on the control inputs are satisfied at the same time.