Robust position control of a lab helicopter under wind disturbances

Flight performances of unmanned helicopters can be affected by wind gusts especially when they are carrying out aggressive mission. In this study, robust position control problem under aggressive manoeuvres is investigated in the presence of time-varying wind disturbances for a lab helicopter. A robust controller is designed in two steps: first, a nominal static linear feedback controller is applied to obtain desired tracking for the nominal system; then, a robust compensator is introduced to restrain the influences of parameter uncertainties, non-linear uncertainties and external wind disturbances. It is proven that the position tracking errors of the closed-loop system can be guaranteed to converge to a neighbourhood of the origin with designated boundary. Experimental results on the 3-degrees of freedom helicopter confirm the effectiveness of this method.