Path Planning of the Swarm Unmanned Aerial Vehicles in the Constrained Environment: A Survey

The path planning for the swarm unmanned aerial vehicles (UAVs) is one of the important directions in the practice. Compared to single UAV path planning, multi drone path planning considers spatial and temporal coordination constraints, flight safety, and other issues. First, the typical path planning methods are discussed with graph-based, mathematical model based and artificial intelligence based categories, where the advantages and disadvantages of each type methods are compared and summarized with adaptable scenarios. Then the swarm path planning methods of UAVs in the constrained environments, i.e. city streets, forests, low space among high ground buildings are discussed. A case study of path planning in the fire rescuing collaborated with ground vehicles and air drones for the large-scale patrolling is provided as well. A summary of the path planning direction with the combination of various algorithms can be drawn for better applications.