Formation control is a prerequisite for the formation to complete specified tasks safely and efficiently. Considering non-symmetrical communication interference and network congestion, this article aims to design a control protocol by studying the formation model with communication delay and switching topology. Based on the requirements during the flight and the features of the motion model, the three-degrees-of-freedom kinematics equation of the UAV is given by using the autopilot model of longitudinal and lateral decoupling. Acceleration, velocity, and angular velocity constraints in all directions are defined according to the requirements of flight performance and maneuverability. The control protocol is adjusted according to the constraints. The results show that the improved control protocol can quickly converge the UAV formation state to the specified value and maintain the specified formation with communication delay and switching topology.

This paper focuses on the application of a cross-flow fan (CFF) to generate propulsion for a submersible aircraft with a flying wing configuration. A numerical method is established to simulate the CFF operating both in the air and underwater. This paper then investigates the fluid dynamic characteristics of the CFF, including the velocity field, the pressure field, the cavitation distribution, the lift, and the thrust. It is concluded that proper lifts and thrusts can be obtained when the rotating speed and the angle of attack are reasonably designed. This work provides a valuable numerical methodology for studying the fluid dynamic characteristics of the CFF operating in different media and offers a technical basis for the selection of a motor system for submersible aircraft.

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