Mathematical Modeling and Experimental Identification of a Model Helicopter

This paper presents a new mathematical model for a model-scale helicopter. Working from first principles and basic aerodynamics, the equations of motion for full six degree-of-freedom motion are derived. The control inputs considered are the four pilot commands from the radio transmitter: roll, pitch, yaw, and thrust. The model helicopter has a fast time-domain response due to its small size, and is inherently unstable. A flybar is used to augment the stability of a model helicopter to make it easier for a pilot to fly. The main contribution of this paper is to model the interaction between the flybar and the main rotor blade; it is shown how the flapping of the flybar increases the stability of the model helicopter as well as assists in its actuation. After the mathematical model is derived, some preliminary system identification experiments and results are presented. The paper ends with conclusions and a short description of future work.