Tuning of Airplane Flight Dynamic Model Using Flight Testing

Abstract

Airplane parameter identification is a crucial subject in aeronautics specially when there is a lack of information about airplane data such as aerodynamic coefficients, stability and control derivatives in addition to propulsion system data. In this paper, the longitudinal motion of a per-developed airplane flight dynamic model is verified and tuned using flight testing. The studied airplane is a small propeller driven RC airplane. Complete development, from cradle to grave, of flight test program to the studied airplane is conducted in order to estimate the airplane longitudinal aerodynamic and propulsion data. The flight test data is collected using available navigation onboard sensors and microcontroller then, data is recorded in both onboard flash memory and ground station PC through telemetry data link for further investigation. Flight dynamic model tuning is performed by altering the original dynamic model structure to include adjustable gains. Then, an optimization problem is formulated to find out the best values for these gains that make the results on both simulation model and flight testing as near as possible. The nonlinear least square method is used as an optimization technique. It is concluded that airplane parameter estimation from flight test data improves the accuracy of the developed flight simulation model since the results show that the simulation model outputs are more close to flight test data after model tuning.