A Mobile Robot Platform for Wireless Charging of Agricultural Underground Sensor Networks

The deployment of large-scale buried sensor networks in agriculture and environmental monitoring is often constrained by the limited lifetime and accessibility of batteries. This work presents a mobile wireless power transfer (WPT) solution that leverages a ground robot to autonomously recharge buried receivers via electrodynamic wireless power transmission (EWPT). The recharging system features a rotating permanent magnet transmitter mounted on a mobile robotic platform, powered by the robot's onboard 24 V supply and controlled via an ESP32 microcontroller. The transmitter wirelessly powers compact rotating magnet receivers located up to 25 cm, enabling simultaneous power delivery to multiple receivers. At 18 cm, three 1.1 cm3 receivers collectively produced 405 mW at 467 Hz. To our knowledge, this is the first demonstration of an agricultural ground robot system for recharging underground sensor networks and represents a significant step towards scalable, maintenance-free power delivery for distributed sensing applications in agriculture and beyond.