Model identification of a small-scale air vehicle for loitering control design

This paper aims to investigate theoretically and experimentally the dynamic behaviors of the pitch and roll motions of a small-scale unmanned air vehicle in loitering flight. Two fourth-order ARX (AutoRegressive with eXogenous input) models are successfully identified, and the performance analysis is carried out based on the flight test data. The validity of the identified model is verified by both time domain model prediction and frequency domain spectral analysis. With the proposed ARX models, two compensators are further designed using a frequency technique to improve the transient performance of the pitch and roll control channels. Simulations and experiments demonstrate that the proposed ARX model-based compensation control design strategy can improve the flight performance.