针对未知扰动作用下的六旋翼无人机姿态稳定控制问题，提出一种非线性前馈补偿的六旋翼无人机姿态稳定反步控制方法。采用非线性未知输入观测器，估计无人机的未知外部扰动，再引入Sigmoid跟踪微分器前馈补偿该扰动估计，进而改进设计六旋翼无人机的姿态稳定反步控制器。进一步，建立姿态跟踪偏差闭环系统的稳定性结果。对比仿真实验验证了所提方法的有效性和优越性。

Aiming at the attitude stabilization control problem of hexacopters subject to unknown disturbance, a nonlinear feedforward compensation backstepping control method for attitude stabilization of hexacopter is proposed. The nonlinear unknown input observer is used to estimate the unknown external disturbance of the unmanned aerial vehicle. Then the Sigmoid tracking differentiator feedforward is introduced to compensate the estimated disturbance, which improves the attitude stabilization backstepping controller of the hexacopter. Furthermore, the stability results of the attitude tracking deviation closed-loop system are established. Some comparative simulation experiments verify the effectiveness and superiority of the proposed method.