Switching robust control for a nanosatellite launch vehicle

The attitude control of a launch vehicle is a challenging task due to the dramatically varying vehicle dynamics along a flight path. The objective of this paper is to design a switching robust control strategy for launch vehicles, applied here to a notional nanosat launch vehicle. In order to control the rocket along a trajectory ascending through the Earth's atmosphere, a set of operating points at different times along the flight path are selected, the corresponding dynamics models of the rocket are obtained via linearization, and a robust H∞H∞ controller is designed for each operating point using the linear matrix inequality approach. These controllers are applied to the nonlinear plant model via a switching strategy when the rocket flies along the flight path. Both linear and nonlinear simulation results are given to show the performance of the closed-loop system.