Robust control design based on identified model for autonomous flight system of an unmanned helicopter

Conventional unmanned helicopters are used to spray agricultural chemicals and take aerial photographs. In the near future, the aircrafts are expected to be used for a wide array of activities, such as rescuing and fire fighting. Then, an autonomous flight using several sensors typified by a global positioning system (GPS) is highly expected. In this paper, first, system identification experiments for a large-scale unmanned helicopter are carried out to obtain a numerical model of aircraft dynamics. The attitude error of the helicopter is compensated by a stability augmentation system that permits the experiments during the flight. System identification results are shown on the dynamics using the measured input and output data. Next, the position control systems based on the H_∞ control theory is constructed by using the identified model. Finally, the position control experiments suggest that the proposed modeling and design approach is effective enough for practical applications.