A Separation and Rendezvous Control Method for the UAV-USV System Based on Distributed NMPC

Most of the recent UAV-USV systems consist of only one USV and one UAV and they cannot operate uninterruptedly. And the information transmission among the USV and the UAV is usually unidirectional. Therefore, a conceptual UAV-USV system that includes one USV and some UAVs is constructed to take the different advantages of the UAV group and USV. To realize the uninterrupted operating, two groups of UAVs take turns to operate and rotate by a real-time energy-aware mechanism. To realize the cooperation between UAVs and the USV, the bidirectional communication topology is introduced and separated into two unidirectional independent communication topologies. To protect the actuator and prolong the durability of the system, the increment of the input vector is constrained. In addition, the unknown disturbances are dealt with the extended Kalman filter for each independent UAV or USV. These improvements are incorporated into a control method based on the Distributed NMPC (nonlinear model predictive control). Besides, the recursive feasibility and stability of this control method are proved. And the centralized NMPC method is introduced to confirm the superiority of this method. Numerical experiments are provided to demonstrate the effectiveness of the proposed method.