Robust control of helicopter with suspended load

A helicopter's vertical takeoff and landing as well as its ability to hover, make it ideal for carrying a suspended load, which facilitates several applications in military and in places that are inaccessible by humans. This paper considers a helicopter having a suspended load that leads to the degradation of the helicopter control due to the increase in work load, which in worst case may lead to instability or a serious accident. This work proposes an H-infinity controller for a helicopter-slung load system in hovering condition. The controller used in this paper robustly stabilizes the helicopter even in the presence of load oscillations. This work shows sufficient control action that must be given by the helicopter in order to reduce the load swing and the results also show in the response on the effect of load swing with and without the controller.