Identification ofAttitude Flight Dynamics for

Theunconventional airframes usedbymany smallfixed-wing unmannedaerial vehicles (UAVs)pose difficulties in determining theirdynamicmodels accurately. Thisisfurther complicated by thelow Reynolds Numbersflight regimes encountered bythese aircraft. Thispaperstudies theattitude flight dynamics identification ofan unconventional model-scale UAV whichhasonlytwoindependently actuated elevon surfaces (norudder orelevators). Thestudy presents thefirst steps towards thedevelopment ofautopilots forthiskindof UAV. Utilizing thereal-time flight datacollected froma human-controlled testflight, thestandard identification approaches wereapplied toobtain aMIMO linear model withgiven configuration deduced fromatheoretical study. Thesimulation-based validation ofasimplified modelwas undertaken whichshowsacceptable modelling accuracy. Furtherflight tests controlled by an autopilot tuned according tothemodelarecurrently being undertaken. IndexTerms- UAV, roboticaircraft, system identification, autopilot, unconventional airframes.