System Identification of Fixed-wing UAV with Multi-segment Control Surfaces

For a fixed-wing unmanned aerial vehicle flight in turbulent environments, distributing aerodynamic load of single aileron through multiple segments can provide rapid actuation, precise roll and heave control while also having the potential to improve yaw response for tail-less (flying wing) aircraft. This paper investigates identification of multi-segment unmanned aerial vehicle (SUAV) via aileron (two segments) instead of the conventional control. Only roll axis is considered in this paper given it represents the most sensitive axis to atmospheric disturbances. The multi-segment aileron is configured as a multi-input and single-output system and each segment is regarded a control input. Experiments are conducted in a wind tunnel to determine the frequency response of the system and the corresponding transfer functions. The experimental results and the mathematical models indicate that interaction between various aileron surfaces is nonlinear. An understanding of this non-linearity aids future development of precise maneuverability, energy efficient control and highly stable operation under severe air turbulence.