A gust-attenuation robust H∞ output-feedback control design for unmanned autonomous helicopters

This paper presents a hierarchical inner-outer loop-based approach to the longitudinal and lateral control of a small unmanned helicopter in the presence of parameter uncertainties and exogenous disturbances. The outer loop employs robust H_∞ output feedback to attenuate the wind disturbance and track the reference trajectory, while the inner loop controller is proposed to solve the parameter uncertainties problems using robust H_∞ static output feedback. The obtained control method takes advantage of the feature of hierarchical structure ensuring the stability of the flight attitude. Finally, the validity of the proposed control strategy is verified through simulation results.