In a warehouse the size of three football fields, 3,000 robots move at 13 feet per second, sliding to avoid each other in a pleasant dance programmed by artificial intelligence. What do they hope to accomplish? The goal is to get your groceries in as little time as possible. The British online retailer Ocado runs the warehouse in southeast London, which is equipped with the most advanced automated equipment. The Ocado Smart Platform (OSP) was originally developed for the company’s usage, but it is now available to other supermarkets.

The bots, which look like washing machines on wheels, move like chess pieces over a grid. A stack of up to 21 containers is hidden beneath each tile. The containers hold some of Ocado’s 50,000 products, which are stored based on data that tells when they will be needed. When the warehouse receives an order, the bots wake up and run to the container they need, passing each other within five millimeters. Alex Harvey, Ocado Technology’s chief of advanced technologies, adds, “We basically play chicken with them: they go on a collision course only to divert at the last moment.” The bots aren’t independent; rather, they’re guided by a system that plans their routes for them, similar to air traffic control. Each bot includes a grasping mechanism that allows it to handle one container. For example, if a product is stored five containers down, four bots will remove the containers above it first, freeing up space for a “hero” bot who is completing an order.

When the “hero” bot has a container in its hands, it transports it to a picking station, where a person selects it and adds it to an order (or another robot, depending on the technology used in each warehouse). The completed order is then transferred to a van for final delivery. “Labor costs are one of the key driving factors in the cost of groceries,” says Harvey, “and our goal is to try to automate these very repetitive, not particularly exciting human operations in the warehouse.