  The application of autonomous UAVs to infrastructure inspection tasks
provides benefits in terms of operation time reduction, safety, and
cost-effectiveness. This paper presents trajectory planning for
three-dimensional autonomous multi-UAV volume coverage and visual inspection of
infrastructure based on the Heat Equation Driven Area Coverage (HEDAC)
algorithm. The method generates trajectories using a potential field and
implements distance fields to prevent collisions and to determine UAVs' camera
orientation. It successfully achieves coverage during the visual inspection of
complex structures such as a wind turbine and a bridge, outperforming a
state-of-the-art method by allowing more surface area to be inspected under the
same conditions. The presented trajectory planning method offers flexibility in
various setup parameters and is applicable to real-world inspection tasks.
Conclusively, the proposed methodology could potentially be applied to
different autonomous UAV tasks, or even utilized as a UAV motion control method
if its computational efficiency is improved.
