  Atmospheric flight phase of a launch vehicle is utilized to evaluate the
performance of an H-infinity controller in the presence of disturbances.
Dynamics of the vehicle is linearly modeled using time-varying parameters. An
operating point was found to design a robust command tracker using H-infinity
control theory that guarantees a stable maneuver. At the end, the controller
was employed on the launch vehicle to assess the capability of control design
on the linearized aerospace vehicle. Experimental results illustrate the
excellent performance of the H-infinity controller and accurate tracking
implemented by the autopilot. Also the robustness of the entire system against
disturbances is demonstrated to be acceptable.
