System identification of small-size unmanned helicopter dynamics

Flight testing of a fully-instrumented model-scale unmanned helicopter (Yamaha R-50 with 10 ft. diameter rotor) was conducted for the purpose of dynamic model identification. This paper describes the application of CIFER system identification techniques, which have been developed for full size helicopters, to this aircraft. An accurate, high-bandwidth, linear state-space model was derived for the hover condition. The model structure includes the explicit representation of regressive rotor-flap dynamics, rigid-body fuselage dynamics, and the yaw damper. The R-50 configuration and identified dynamics are compared with those of a dynamically scaled UH-1H. The identified model shows excellent predictive capability and is well suited for flight control design and simulation applications.