System Identification and Controller Optimization of a Quadrotor UAV

Multi-rotor aircraft, such as the quadrotor, are increasingly popular for small-scaled VTOL UAVs. In order to develop an effective control system through simulation techniques, obtaining an accurate dynamic model of a given quadrotor is crucial. Moreover, given the anticipated stringent safety requirements, fault tolerance will be a crucial component of UAV certification. Accurate dynamic modeling and control of this class of UAV is an enabling technology and crucial for future commercial applications. In this paper, the extraction of the bare-airframe dynamic model of a quadrotor UAV in hover condition using frequency-domain system identification techniques and its simulation is presented. The model is verified in the time-domain using dissimilar flight test data not used in the identification. The dynamic model and onboard PID controller are simulated and verified in Simulink®. Then, the controller is optimized to achieve significantly improved performance in both simulation analysis and flight tests. This paper presents details of the quadrotor system design, model extraction techniques, dynamic model verifications, controller optimization and flight test results.