A Fluid Dynamic Based Coordination of a Wireless Sensor Network of Unmanned Aerial Vehicles: 3-D Simulation and Wireless Communication Characterization

A fluid dynamic algorithm based on smoothed particle hydrodynamics (SPH) is proposed for coordination of a team of unmanned aerial vehicles (UAVs) in a wireless sensor network. SPH is a Lagrangian particle method typically used to model compressible and quasi-incompressible fluid flows. In this study, SPH is used to develop a decentralized controller for a swarm of fixed-wing UAVs, which move in 3-D space under constraints of airspeed and turning radius. Vector field path-following is used to guide the swarm towards the goal. We investigate circular, racetrack and counter-rotating loiter patterns for the UAVs in the goal region. This fluid dynamics coordination treatment allows UAVs to avoid collisions with obstacles and other flying UAVs. 3-D simulations are used to test the SPH-based control algorithm. Simulations were used to explore special cases, such as the modeling of obstacles with virtual SPH particles, and the use of a variable kernel to control the inter-vehicle separation. Finally, an aerial mobile sensor network is set up using SPH as the control mechanism, and an experimental characterization of air-to-air and air-to-ground communications is conducted. The experiments use two ground stations and three Delta-wing UAVs with a wingspan of 32 inches as nodes. Each node has a IEEE 802.15.4 ZigBee radio operating in the 2.4 GHz band. The low computational costs involved in the distributed SPH-based control algorithm make it an attractive option for implementation on simple inexpensive microprocessors. The results of simulations and experiments demonstrate the viability of setting up a mobile sensor network of inexpensive UAVs based on SPH.