  Achieving safe and precise landings for a swarm of drones poses a significant
challenge, primarily attributed to conventional control and planning methods.
This paper presents the implementation of multi-agent deep reinforcement
learning (MADRL) techniques for the precise landing of a drone swarm at
relocated target locations. The system is trained in a realistic simulated
environment with a maximum velocity of 3 m/s in training spaces of 4 x 4 x 4 m
and deployed utilizing Crazyflie drones with a Vicon indoor localization
system. The experimental results revealed that the proposed approach achieved a
landing accuracy of 2.26 cm on stationary and 3.93 cm on moving platforms
surpassing a baseline method used with a Proportional-integral-derivative (PID)
controller with an Artificial Potential Field (APF). This research highlights
drone landing technologies that eliminate the need for analytical centralized
systems, potentially offering scalability and revolutionizing applications in
logistics, safety, and rescue missions.
