Collaborative Payload Transport using a Four-Quadcopter Swarm with RTK and MQTT-based Coordination

Abstract

This paper presents the design and experimental validation of a collaborative payload transport system using a swarm of four quadcopters in an outdoor environment. The system employs a leader-follower framework where the leader drone generates mission commands and trajectory setpoints, which are disseminated to follower drones using MQTT over a Wi-Fi mesh. High-precision positioning is enabled via a Real-Time Kinematic (RTK) GNSS system, with RTCM correction data routed through a cloud server and broadcasted within the swarm using telemetry radios. Each quadcopter is equipped with PX4 Autopilot and a Raspberry Pi Zero 2 W for mission control and inter-agent communication. The system successfully demonstrates stable transport of a 1 kg payload, maintaining formation during ascent, directional maneuvers, and descent. This work serves as a scalable platform for multi-agent cooperative aerial manipulation in GPS-available outdoor settings.