Structured H-infinity and Linear Parameter Varying Control Design for the VEGA Launch Vehicle

This article describes the application of two robust control design techniques: the structured H-infinity and the linear parameter varying (LPV) synthesis techniques to the design of the rigid-body atmospheric phase control system of a launch vehicle. The structured H-infinity synthesis technique allows to perform a robust H-infinity-based design while keeping the same TVC controller architecture used by the launch vehicle. The LPV design approach can synthesize a scheduled controller by expressing the control problem in terms of time-varying parameters. The main goal is to explore the potentials for improvement by using a robust control design technique, which may reduce the tuning and design effort required for each mission, as well as, provide a more systematic and automated design approach. Both synthesis approaches are applied to the actual VEGA VV05 mission data. Finally, the two synthesized controllers are validated and compared with the VEGA baseline controller using a high-fidelity, nonlinear simulator.