In a warehouse the size of three football fields, 3,000 bots scuttle along at 13 feet per second swerving to avoid each other in a sophisticated dance guided by artificial intelligence. What do they want to achieve? To obtain your groceries as quickly as humanly possible. The British online retailer Ocado operates the warehouse in southeast London, which is equipped with the most advanced automation technologies. The Ocado Smart Platform (OSP) was originally developed for the company’s use, but it has proven to be so successful that it is now licensed to other supermarkets.

The bots, which resemble washing machines on wheels, move like chess pieces on top of a grid. Each square conceals a stack of up to 21 containers beneath the floor. The containers are stocked with some of Ocado’s 50,000 items, which are stored based on an algorithm that forecasts when they will be needed. When an order is issued to the warehouse, the bots awaken and race to the container they need, passing within five millimeters of each other. “We basically play chicken with them: they go on a collision course only to divert at the last moment,” says Alex Harvey, chief of advanced technology at Ocado Technology. The bots are not self-autonomous; instead, they are guided by a system that functions similarly to air traffic control, organizing their paths for them. The bots each have a gripping mechanism and can take up one container. For example, if a product is stored five containers down, four bots will remove the containers above it first, making room for a “hero” bot who is fulfilling an order.

When the “hero” bot has a container in its grasp, it transports it to a picking station, where a person (or another robot, depending on the technology deployed in each warehouse) will select the item and add it to an order. The completed order is subsequently transferred to a van for delivery by bots. “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.”