Abstract:

In this work, the inner and outer loop control strategy is adopted for the unmanned aerial vehicles (UAVs) formation system. Firstly, a sliding mode control method based on memory event?triggered mechanism (METM) is proposed for the position subsystem under delay and disturbance. The second?order model is established for each UAV, and the leader?follower framework is adopted to realize the desired flight formation. Secondly, an adaptive METM is proposed to alleviate the transmission burden, in which control input feedback is introduced. For the resulting communication delay of the control input in the proposed METM and the external disturbance to the system, a sliding mode controller is designed, which maintains desirable control performance and solves the influence of communication delay and bounded disturbance to a certain extent. Thirdly, the stability of the closed?loop system is proved by applying Lyapunov theory and H_∞ control theory, and a method that facilitates solving controller gain and triggering parameter through a series of linear matrix inequalities (LMIs) is proposed. Moreover, based on the obtained virtual control quantity, a tracking controller is designed for the attitude subsystem. Finally, a simulated example is exploited to verify the effectiveness of the proposed method.

Key words: UAVs formation, Communication delay, Bounded disturbance, Memory event?triggered mechanism, Sliding mode control

摘要：

针对多无人机编队系统，采用了内外环控制策略。首先，在考虑通讯时延和有界外部干扰的情况下，针对位置子系统提出了一种基于记忆事件触发机制的滑模控制方法。针对所建立的无人机二阶模型，采用领航?跟随法实现期望飞行编队。其次，为降低编队过程中的通讯负荷，设计了基于输入反馈和跟踪误差的新型自适应记忆事件触发机制，针对由此产生的输入通讯时延和系统所受的外部干扰问题，设计了滑模控制器，保证了控制性能并抑制了通讯时延和有界干扰的影响。再次，应用Lyapunov理论和 H_∞ 控制理论完成了闭环系统稳定性证明，并且给出了便于滑模控制器增益和触发参数求解的策略。从次，基于所获得的虚拟控制量，针对姿态子系统设计了跟踪控制器。最后，通过仿真验证了所提方法的有效性。

关键词: 多无人机编队, 通讯时延, 有界干扰, 记忆事件触发, 滑模控制