关键词: 固定翼UCAV, 飞行控制, 扩张状态观测器, 超扭曲, 二阶滑模控制

Abstract: Aiming at uncertainties and external disturbances in fixed-wing UCAV systems, an adaptive super twisting sliding mode controller based on extended state observer is designed to suppress system’s disturbances in this paper, thus the control performance of UCAV has bean improved. A six-degree-of-freedom nonlinear model of fixed-wing UCAV is established, then the extended state observer for attitude control and velocity control is designed respectively to estimate states and external disturbances which are difficult to measure accurately in the model. According to the principle of singular perturbation, an adaptive super twisting sliding mode controller is designed for attitude and velocity respectively to achieve tracking control of UCAV’s attitude and velocity. To verify the controller designed in this paper, a certain type of nonlinear model of fixed-wing UCAV is used to simulate and compared with the traditional active disturbance rejection control based on sliding mode control method. The simulation results show that the adaptive super twisting sliding mode controller based on extended state observer designed in this paper has smaller overshoot and steady state error.

Key words: fixed-wing Unmanned Combat Aerial Vehicle（UCAV）, flight control, extended state observer, super twisting algorithm, second-order sliding mode control