A novel cascade controller for a helicopter UAV with Small Body Force compensation

Small helicopter control is a topic of wide interest. The generally accepted model includes the effect of so-called Small Body Forces (SBF) which couple the rotational inputs to the translational dynamics. The SBF include the tail rotor thrust and the lateral forces due to the main rotor flapping which are used to force the rotational dynamics. Since the SBF render the model non-minimum phase, it has become customary in the literature to neglect their effect in order to design a model-based control with rigorously defined performance guarantees. We present a control design which directly compensates the influence of the tail rotor component of the SBF on the translational dynamics.