Drones bring greater efficiency to inventory management

The use of drones to read radio frequency identification (RFID) tags for inventory management in large warehouses might at last make the tags as efficient as originally envisioned, saving retailers billions of dollars.

Researchers at the MIT Media Lab have developed a system that enables small unmanned aircraft systems (UAS) to read RFID tags from tens of yards away while identifying the tags’ locations with an average error of about 7.5 inches. They believe the system could be used in large warehouses for continuous monitoring—to prevent inventory mismatches—and to locate individual items, enabling employees to rapidly and reliably meet customer requests.

RFID tags were intended to revolutionize supply chain management. The cheap, battery-free tags receive power wirelessly from scanners and then broadcast identifying numbers. This helped warehouse managers log inventory more efficiently than manually reading and recording box numbers.

However, the scale of modern retail operations made RFID scanning inefficient. For example, Walmart reported in 2013 losing $3 billion in revenue because of mismatches between inventory records and stock. Even with RFID technology, it could take a large retail store three months to perform a complete inventory review. Mismatches often went undiscovered until exposed by a customer request.

“Between 2003 and 2011, the U.S. Army lost track of $5.8 billion of supplies among its warehouses,” said Fadel Adib, an MIT assistant professor of media arts and sciences. “In 2016, the U.S. National Retail Federation reported that shrinkage—loss of items in retail stores—averaged around $45.2 billion annually.”

By enabling drones to find and localize items and equipment, Adib said the research provides a fundamental technological advancement for solving the problem.

The greatest challenge MIT researchers faced in designing the system was using current autonomous navigation technology. Drones safe enough to fly in close proximity to humans had to be small, lightweight and have plastic rotors to avoid causing injuries. But these drones were too small to carry RFID readers with a range of more than an inch.

Researchers solved the problem by using the drones to relay signals emitted by a standard RFID reader. This not only solved the safety problem, but also meant drones could be deployed in conjunction with existing RFID inventory systems without the need for new tags, readers or reader software.

The MIT researchers described their system—dubbed RFly—in a paper presented at the annual conference of the Association for Computing Machinery's Special Interest Group on Data Communications.