Drives and Controls Magazine

Autonomous AGV needs no guides

05 October, 2010

Hitachi Plant Technologies has developed an autonomous AGV (automatic guided vehicle) which can estimate its position and guide itself along a path on an electronic map without needing fixed guides.

Conventional AGVs are usually guided using wires, magnetic tapes, markers, or mirrors. If changes are needed to the routing, considerable work is needed to move and reinstall these guides.

The new autonomous AGV (above) uses a laser distance sensor to acquire information about its position and uses an on-board PC to generate an electronic map of the route and recognise its location automatically. Any routing changes can be implemented rapidly, and it is easier to re-arrange production lines without having to worry about AGV tracks.

When conventional AGVs encounter obstacles, they stop until the obstacle is removed. When the autonomous AGV detects an obstacle, it sends an audio alert to remove the obstacle. If this does not happen within a certain time period, the vehicle can route itself around the obstacle.

Because guidance systems that use wires and magnetic tapes need to detect magnetic fields and issue control signals, they cannot be used in areas with steel plates or magnetic materials. Because the autonomous AGVs use information provided by an electronic map, they can move over floor gratings, even in areas such as clean rooms.

The new AGVs use laser distance sensors for guidance, combined with safety sensors that slow them down or stop them, depending on the distance to an obstacle. If the obstacle is far away, they can travel at high speeds and slow down as they approach it, leading to faster average speeds. Hitachi says speeds of up to 7.2km/h are possible in locations where no people are present.
The first order for an autonomous AGV has come from a glass manufacturer, which will use it to transport loads of up to four tonnes. Hitachi is aiming for sales worth 4 billion yen (£30m) by 2015.