Linear time-periodic control and analysis of helicopter air resonance

This dissertation presents the design and robust stability analysis of time-periodic control laws of the helicopter air resonance phenomenon. A modern technology based on piezo-actuated active blade trailing edge flaps is used to control the rotorblade motion. These actuators and the designed control laws are tested in several identification and closed-loop flight campaigns, flown as a world first for this purpose. Robustness analysis of the time-periodic closed-loop system is performed before the first closed-loop flight in order to ensure robust stability against model uncertainties. This work therefore focuses on three core aspects comprising the control of air resonance (from simulations and experimental data), the trailing edge flap actuators, and the robust stability analysis of linear time-periodic systems.