  This paper presents a formation control approach for contactless
gesture-based Human-Swarm Interaction (HSI) between a team of multi-rotor
Unmanned Aerial Vehicles (UAVs) and a human worker. The approach is intended
for monitoring the safety of human workers, especially those working at
heights. In the proposed dynamic formation scheme, one UAV acts as the leader
of the formation and is equipped with sensors for human worker detection and
gesture recognition. The follower UAVs maintain a predetermined formation
relative to the worker's position, thereby providing additional perspectives of
the monitored scene. Hand gestures allow the human worker to specify movements
and action commands for the UAV team and initiate other mission-related
commands without the need for an additional communication channel or specific
markers. Together with a novel unified human detection and tracking algorithm,
human pose estimation approach and gesture detection pipeline, the proposed
approach forms a first instance of an HSI system incorporating all these
modules onboard real-world UAVs. Simulations and field experiments with three
UAVs and a human worker in a mock-up scenario showcase the effectiveness and
responsiveness of the proposed approach.
