Abstract: For Qball-X4 four-rotor unmanned aircraft with its own characteristics, creating nonlinear model of system and adopting double closed-loop control algorithm with inner and outer loop are controlled by attitude and position respectively. Linear quadratic regulator is easy to solve state feedback control rate quickly, and has good robustness, thus LQR is utilized to design attitude inner loop controller. Due to the PID control algorithm has simple structure, strong robustness, thus PID is utilized to design position loop controller. Utilize Matlab/Simulink and flight test to verify control algorithm, and the result shows that the control algorithm can successfully achieve the hovering control, and achieve good control effect.

Key words: four-rotor unmanned aircraft, nonlinear model, linear quadratic regulator, PID control algorithm

摘要： 针对Qball-X4四旋翼无人飞行器的自身特点，建立系统的非线性模型，采用姿态内环和位置外环的双闭环控制算法。线性二次型调节器（LQR）可以快速简便地求解出最优的状态反馈控制率，并且具有良好的鲁棒性，因而利用LQR控制算法来控制姿态内环。由于PID控制算法结构简单、鲁棒性强，因而控制位置外环。通过Matlab/Simulink和飞行试验对控制算法进行仿真和验证，结果表明，设计的控制算法能成功地实现飞行器的悬停控制，并达到较好的控制效果。

关键词: 四旋翼无人飞行器, 非线性模型, 线性二次型调节器, PID控制算法