Frequency domain system identification for a small, low-cost, fixed-wing UAV

This paper describes a practical and systematic procedure for modeling and identifying the flight dynamics of small, low-cost, fixed-wing uninhabited aerial vehicles (UAVs). The procedure is applied to the Ultra Stick 25e flight test vehicle of the University of Minnesota UAV flight control research group. The procedure hinges on a general model structure for fixed-wing UAV flight dynamics derived using first principles analysis. Wind tunnel tests and simplifying assumptions are applied to populate the model structure with an approximation of the Ultra Stick 25e flight dynamics. This baseline model is used to design informative flight experiments for the subsequent frequency domain system identification. The final identified model is validated against separately acquired time domain flight data.