Persistent Environmental Monitoring with Distributed Online Assignment of Charging Stations

This paper investigates persistent environmental monitoring of a target area using a drone network. We first design control barrier functions (CBFs) to enforce drones to meet various specifications including battery charging. The combination of coverage control and CBF-based online optimization is shown to achieve persistent monitoring while meeting the specifications. However, the CBF for battery charging enforces each drone to return to a preassigned charging station before battery exhaustion, which may degrade efficiency for the operation. To address the issue, we incorporate a high-level control mechanism for online assignment of charging stations into the persistent coverage control. In order to design the high-level controller, we present a distributed solution to the assignment problem based on so-called alternating direction method of multipliers. The overall system is finally demonstrated through simulation.