A wireless recharging system for electrical agriculture robots with autonomous docking

In this work we present a system for the autonomous recharge of the batteries of an electric powered mobile robot, developed in the context of agricultural robotics. The system is composed of a wireless charging station at high power which can provide up to 4 kW and an autonomous docking algorithm exploiting a camera and a laser range nder. The wireless charging station consists of a power supply and two coils for the wireless power transfer, one attached to the docking station and one attached at the bottom of the robot. Since a mechanical plug is not used to establish the electrical connection a high precision alignment docking is not required. However, the better the two coils are aligned, the more power is transferred and the eciency of the recharging system increases. The robot navigation module is based on the standard navigation stack of Robot Operating System (ROS). This is used to get close to the docking station, while a ne grain motion planner was specically developed for the docking task. It generates a precise alignment of the robot's coil with the ground coil by fusing the sensory information from the camera and the laser range nder. A detailed description of the wireless charging station and of the motion planner is reported together experiments on a real robot showing the good performances of the complete system.