Autonomous mobile robots (AMR) are robots that find their own way around a warehouse or a factory floor, moving goods, bins and pallets with no tracks and no driver. Each robot builds a map of the building, works out where it is on that map, and plans its own route to its next job.
An older kind of robot, the automated guided vehicle (AGV), follows a fixed path. The path is a magnetic strip, a painted line or a wire under the floor. If a box is left in the path, the AGV stops and waits until someone moves it. If the factory changes its layout, the path must be laid again. An AMR has no fixed path. When it finds a box in its way, it plans a route around it.
An AMR senses its surroundings with lidar, a sensor that sends out laser light and measures how long the light takes to bounce back from walls, racks and people. Many AMRs also carry cameras. As the robot drives, it compares what its sensors see with its map, and so knows its position to within a few centimetres. This method is called SLAM, short for simultaneous localisation and mapping. The robot must decide in a fraction of a second whether to brake for a person who steps out. So it does these calculations on its own computer, not in a distant data centre. Computing done in the machine itself, close to the data, is called edge computing. A separate program, the fleet manager, runs on a server in the building. It gives each robot its next job and sends robots to charge their batteries in turn.
Consider a car-parts factory in Chakan, near Pune. Assembly line 3 uses a crate of 200 brake pads about every 40 minutes. A forklift used to bring the crates from the store, 300 metres away, whenever a worker phoned for one. Now, when the line is down to its last crate, the line's system sends a request to the fleet manager. The fleet manager sends the nearest free AMR. The robot collects a full crate from the store and crosses the factory along the aisle it shares with people and forklifts. It slows down near the workers at the line, drops the full crate and takes the empty one away. When its battery falls below 30 percent, it drives to a charger by itself.
In a warehouse, an AMR often works beside a picker. The warehouse management system sends the picks, the robot leads the picker from bin to bin, and it then carries the full totes to the packing area. Larger AMRs lift whole pallets, the work a forklift does.
An AMR moves goods from place to place, but it does not handle them. For picking up, placing or assembling parts, a factory uses an industrial robot or a cobot, and some AMRs carry a cobot arm on top. Goods-to-person robots are a special kind of AMR that carry shelves inside a grid closed to people.