关于四旋翼无人机目标轨迹跟踪控制的研究

摘要

针对四旋翼无人机在飞行过程中易受外界干扰影响的问题,提出了利用干扰观测器的滑模控制方法,保证空间轨迹能够快速平滑地跟踪目标信号.首先,为了避免产生奇点,采用单位四元数描述系统姿态;其次,针对位置子系统的欠驱动特性,引入虚拟控制力,同时解算出实际输入升力和目标姿态;再次,考虑到位置和姿态子系统模型中干扰力和干扰力矩的存在,设计了干扰观测器对其进行在线估计,并利用滑模控制方法设计出输入控制律,保证对目标姿态和参考轨迹的跟踪.最后,仿真结果验证了上述系统控制器的有效性和稳定性.%An observer based sliding mode control method was proposed for the quadrotor UAV to track the desired trajectory speedily and smoothly in the presence of external disturbances.First of all,to avoid singularity,the attitude was described using unit-quaternions.Secondly,considering the under-actuated characteristic of position subsystem,the virtual control force was introduced to calculate the actual thrust and the desired attitude.Then,two disturbance observers were designed to estimate the disturbance force and moment.With the estimated values,the sliding mode controller was designed to track the desired attitude and the reference trajectory.Finally,the simulation shows the effectiveness of the proposed controller.