Boston Dynamics' Stretch can move 800 heavy boxes per hour
As COVID-19 makes global supply chains especially important, the logistics industry is turning to automation to help keep workers safe and make them more productive. However, many warehouse operations resist traditional automation, namely tasks where the process inputs and outputs are not always clearly defined and cannot be fully controlled.
A new generation of robots with intelligence and flexibility, able to handle the diverse variations that people easily perceive, is appearing in warehouses. A prime example is Stretch, a new robot from Boston Dynamics that can move heavy boxes wherever they need to go, and do so as quickly as an experienced warehouse worker.
Stretch's design differs somewhat from the humanoid and quadruped robots for which Boston Dynamics is best known, such as Atlas and Spot. With its single massive arm, a sensor-equipped gripper with many suction cups, and an omnidirectional mobile base, Stretch can move boxes weighing up to 23 kg from the back of a truck onto a conveyor belt within seconds, at a rate of 800 boxes per hour.
An experienced human worker can move boxes at the same speed, but not all day, whereas Stretch can operate for 16 hours before recharging. This kind of work is punishing on the human body, especially when heavy boxes have to be lifted from the ceiling or floor of a trailer.
“Truck unloading is one of the hardest jobs in a warehouse, and that is one reason we are starting with Stretch. Typically, each truck is unloaded by two people. With Stretch, we want one person to unload four or five trucks at the same time, using Stretch as a tool”
According to him, Stretch is not meant to fully replace people. The idea is that several Stretch robots can make a person an order of magnitude more efficient.
All Stretch needs is to be shown the back of a trailer filled with boxes, and it will work autonomously, placing each box onto a conveyor belt one after another until the trailer is empty. People will still work to make sure everything runs smoothly, and they can step in if Stretch runs into something it cannot handle, but their ongoing work comes down to supervising robots instead of lifting heavy boxes all day.
Reaching this level of reliable autonomy with Stretch took Boston Dynamics years of work, building on its long experience developing strong, fast and agile robots. In addition to the challenge of creating a high-performance robotic arm, the company also had to solve problems that people find trivial but are hard for robots, such as looking at a wall of tightly packed brown boxes and being able to tell where one ends and another begins.
Safety is also a priority, and Stretch follows standards for mobile industrial robots set by the American National Standards Institute and the Association for Advancing Automation. The fact that the robot works inside a truck or trailer also helps protect Stretch from nearby people, and, at least for now, the trailer opening is fenced off while the robot is inside.
Stretch is optimized for moving boxes, a task required throughout the warehouse. Boston Dynamics hopes that in the long term the robot will be flexible enough to apply its box-handling experience wherever it is needed. Beyond unloading trucks, Stretch can unload boxes from pallets, place boxes on shelves, assemble multi-box orders from different locations in the warehouse and, eventually, load boxes onto trucks, which is a much harder problem than unloading because of the planning and precision required.
In the short term, trailer unloading (a part of warehouse work called "receiving") is the best place for a robot like Stretch, agrees Matt Bein, who studies robotics and artificial intelligence at the University of California, Santa Barbara: "Nobody wants to do receiving. It is dangerous, tiring and monotonous."
However, Bein, who for the past two years has led a group of field researchers in a nationwide study of warehouse automation, noted that the work may have important nuances that a robot like Stretch is likely to miss, such as interaction with people who work on other parts of the receiving process.
“It involves exchanging fine, high-speed information about boxes, which people use as key inputs to do their work effectively, and I will be especially impressed if Stretch can handle that”
Boston Dynamics spent most of 2021 turning Stretch from a prototype built largely from parts developed for Atlas and Spot into a production-ready system, with deliveries starting to a select group of customers in 2022 and broader sales expected in 2023. Blankespoor believes such robots could have a huge impact on logistics.
“Despite the success of automation in manufacturing, warehouses are still almost entirely run by hand. We are only beginning to see a new generation of robots that can cope with the variations you see in a warehouse, and that is what we like about Stretch”
