System Identification and Heuristic Control of Segmented Ailerons for Enhanced Stability of Fixed Wing UAVs

Abstract

Different from conventional aircraft, an investigation on system identification and control design has been carried out on a small fixed wing unmanned aerial vehicle (UAV) with a multi-segment ailerons. The multi-segment aileron setup is configured as a multi-input and single-output system and each segment is modeled as a control input. Experiments are conducted in a wind tunnel to determine the frequency responses of the system and the corresponding transfer functions. Multiple PID controllers are designed and implemented in a cascaded form for each control surface. Furthermore, a heuristic switching control strategy is implemented for the aircraft where the multi-segment ailerons perform as a single-segment aileron in a normal flight condition, and adapts to multi-segment control when encountering severe turbulence or a large angle reference change. Experimental results reveal that although each control surface has the capability for stabilization of the aircraft, the proposed control strategy by combining the multiple actuation surfaces reduces the mean squared errors for the roll angle up to $37$ percent in the highly turbulent environment providing superior disturbance rejection properties to the aircraft.