Air-Launch Stability Control of Small Folding-Wing UAV Against Airflow Disturbance

In the launch process of Small Folding-wing UAV (SFUAV), the wings deform from fully folded to fully deployed, resulting in significant variation in the aerodynamic and inertia characteristics. The launch stability is vulnerable to flow interference. To improve the launch safety and stability of air-launch SFUAV, the nonlinear block backstepping control method is adopted to design the active stabilizing controller, and the minimum quadratic programming method is used to allocate the redundant control surfaces. Furthermore, a new compensation term has been designed to improve traditional Dynamic Surface control (DSC) technology. The simulation results showed that the maximum roll angle was about 7° against 10m/s airflow disturbance during the launch phase, which was significantly improved compared to 23° achieved by the PID controller. The proposed nonlinear block backstepping controller made the launch attitude more stable, and the attitude tracking error further reduces.