Robust Vertical/Lateral/Longitudinal Control of an Helicopter with Constant Yaw-Attitude

We consider the problem of controlling the vertical, lateral and longitudinal motion of a nonlinear model of a helicopter maintaining a constant yaw-attitude. Given arbitrary references with suitable restrictions on the time derivatives, we design a nonlinear controller which succeeds in enforcing the desired trajectories robustly with respect to uncertainties characterizing the physical and aerodynamical parameters of the helicopter. Engine dynamic of the main rotor is also taken into account in deriving the control law. Simulation results are finally given showing the effectiveness of the method and its ability to cope with uncertainties on the plant and actuator model.