Turbulence alleviation of unmanned aerial vehicle with fly wing configuration based on longitudinal direct force control

Unmanned aerial vehicle with fly wing configuration can suffer critical loading when flying through atmospheric turbulence. Restricted to the aerodynamic configuration and control surfaces distribution, traditional strategies for gust load alleviation cannot be applied to the fly wing configuration vehicle. Aerodynamic characteristics of control surfaces are contrasted and analyzed. According to the visible differences in force coefficient and moment coefficient of the control surfaces, an alleviation strategy is proposed for the unmanned aerial vehicle with fly wing configuration. In this strategy, all control surfaces cooperate in generating longitudinal direct force while keeping addition moment trimmed. A nonlinear controller is designed based on active disturbance rejection control techniques to compensate for system error and turbulence disturbance by online estimation. Simulation results and their analysis show preliminarily that the g-load response to atmospheric turbulence is improved after applying the longitudinal direct force control strategy and that the nonlinear controller, and the flight attitude and track can maintain stability besides.