集总干扰下六旋翼飞行器的轨迹跟踪控制

Trajectory tracking control for an unmanned hexrotor with lumped disturbance

  • 摘要: 针对复杂集总干扰下六旋翼飞行器轨迹跟踪控制问题,给出了混合积分反步法控制与线性自抗扰控制的控制算法. 首先,通过牛顿-欧拉方程建立六旋翼飞行器的非线性动力学模型,并剖析系统输入输出的数学关系. 其次,根据六旋翼飞行器动力学模型的特点,将其分为位置与姿态两个控制环. 位置环采用积分反步法控制理论设计控制器,通过引入积分项来提高系统的抗干扰能力,消除轨迹跟踪的静态误差;姿态环采用线性自抗扰控制技术设计控制器,通过线性扩张观测器估计和补偿集总干扰影响,提高系统的鲁棒性. 最后,通过2组仿真算例和1组飞行试验验证了本文所提飞行控制算法的有效性. 研究结果表明:该控制算法对集总干扰有较好的抑制作用,能够使六旋翼飞行器既快又稳地跟踪上参考轨迹,具有一定的工程应用价值.

     

    Abstract: In recent years, unmanned aerial vehicles (UAVs) have experienced an important growth both in research activities and industrial field. With the abilities to take off, land vertically, and hover along with natural agility and controllability, a hexrotor can extend the potential roles of UAVs. From the view of mechanical structure, hexrotors can be considered simpler than the helicopters because they do not have the swash-plate and do not need to eliminate the gyroscopic torques created by the spinning motors. However, hexrotors are not only extremely sensitive to control inputs and disturbances, they are also complex systems that are nonlinear, highly unstable and with multiple input-multiple output (MIMO) and a high degree of coupling characteristics. This study proposes a hybrid control algorithm combined integral backstepping control with linear active disturbance rejection control to solve the problem of trajectory tracking control for an unmanned hexrotor with lumped disturbance. First, the nonlinear dynamical model of the hexrotor was deduced with the Newton-Euler equation, and the mathematic relation of the input and the output was analyzed. Second, the hexrotor system was divided into the position loop and the attitude loop according to the characteristic of the dynamical model. In the position loop, an integral backstepping control algorithm was applied to design the controller by introducing an integral term to improve the disturbance resistance and eliminate the static error of the trajectory tracking. In the attitude loop, a linear active disturbance rejection control algorithm was used to design the controller by introducing a linear extended state observer to estimate and compensate for the lumped disturbance. Lastly, the effectiveness of the proposed control algorithm was verified through two simulation cases and a flight experiment. The research results show that the proposed algorithm has a strong ability to resist the lumped disturbance and make the hexrotor quickly and steadily track the referenced trajectory. Hence, the algorithm has an important engineering application value.

     

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