Robot Farmers: Autonomous Orchard Vehicles Help Tree Fruit Production

Abstract

This article presents perception and navigation systems for a family of autonomous orchard vehicles. The systems are customized to enable safe and reliable driving in modern planting environments. The perception system is based on a global positioning system (GPS)-free sensor suite composed of a twodimensional (2-D) laser scanner, wheel and steering encoders, and algorithms that process the sensor data and output the vehicle's location in the orchard and guidance commands for row following and turning. Localization is based on range data to premapped landmarks, currently one at the beginning and one at the end of each tree row. The navigation system takes as inputs the vehicle's current location and guidance commands, plans trajectories for row following and turning, and drives the motors to achieve fully autonomous block coverage. The navigation system also includes an obstacle detection subsystem that prevents the vehicle from colliding with people, trees, and bins. To date, the vehicles sporting the perception and navigation infrastructure have traversed over 350 km in research and commercial orchards and nurseries in several U.S. states. Time trials showed that the autonomous orchard vehicles enable efficiency gains of up to 58% for fruit production tasks conducted on the top part of trees when compared with the same task performed on ladders. Anecdotal evidence collected from growers and workers indicates that replacing ladders with autonomous vehicles will make orchard work safer and more comfortable.