HIGH-ORDER STATE-SPACE SIMULATION-MODELS OF HELICOPTER FLIGHT MECHANICS

This paper describes the formulation and validation of a high-order li nearized mathematical model of helicopter flight mechanics, which incl udes rotor flap and lag degrees of freedom as well as inflow dynamics. The model is extracted numerically from an existing nonlinear, blade element, real-time simulation model. Extensive modifications in the fo rmulation and solution process of the nonlinear model, required for a theoretically rigorous linearization, are described in detail. The val idation results show that the linearized model successfully captures t he coupled rotor-fuselage dynamics in the frequency band most critical for the design of advanced flight control systems. Additional results quantify the extent to which the order of the model can be reduced wi thout loss of fidelity.