[info] technologyreview: robotised, self-allocated warehouses

[Alejandro Dubrovsky]

(
http://www.technologyreview.com/printer_friendly_article.aspx?id=19687
)

Thursday, November 08, 2007
Random Access Warehouses
A company called Kiva Systems is speeding up Internet orders with
robotic systems that are modeled on random access computer memory.
By Kevin Bullis

Squat orange robots and a set of adaptive algorithms are making it
possible to deliver online orders faster. The system, so far installed
in two giant Staples warehouses, allows workers to fill two to three
times as many orders as they could with conventional methods. The
startup that developed the robots and software, Kiva Systems, based in
Woburn, MA, announced yesterday that it is rolling out a third system,
for the pharmacy giant Walgreens.

Kiva Systems' CEO and founder, Mick Mountz, likens the system to random
access memory chips. The warehouse is arranged in a memory-chip-like
grid composed of rows and columns of freestanding shelves. The grid
gives robots access to any product in the warehouse at any time. The
robots serve two basic functions. First, they deliver empty warehouse
shelving units to workers who stock them. The workers might stock one
unit with a mix of paper, various types of pens, and computer software,
all compiled from large pallets that had been delivered to the
warehouse. Then, when a consumer submits an order, robots deliver the
relevant shelving units to workers who pack the requested items in a box
and ship them off. "We turn the whole building into a random access,
dynamic storage and retrieval system," Mountz says.

If a consumer orders an item at 2 P.M. on a Thursday, he says, at 2:01,
a robot can be delivering that order to a worker to pack. If an order
has multiple items, robots will line up for workers as fast as the
workers can pack the items. Once the items are packed, robots can pick
up the boxes, storing them temporarily or delivering them to the
appropriate delivery truck.

Mountz says that the system allows workers to fill orders much faster
than conventional systems do because the robots can work in parallel,
allowing dozens of workers to fill dozens of orders simultaneously. In
one type of conventional system, workers have to walk from shelf to
shelf to fill orders, and all that walking takes time. With the Kiva
system, several robots can be dispatched to collect all the items in an
order at once. The robotic system is also more efficient than
conveyor-based systems, in which elaborate conveyors and chutes send
boxes past workers who pack them as they go by. In such a system, the
slowest part of the line, which could be the slowest worker, limits the
overall speed. With the help of the robots, each worker fills an entire
order, so one worker doesn't slow everyone else down.

The robotic system is also faster because the entire warehouse can
adapt, in real time, to changes in demand. Robots move shelves with
popular items closer to the workers, where the shelves can be quickly
retrieved. Items that aren't selling are gradually moved farther away.
More-conventional warehouses can also be adaptive, Mountz says, but it
takes much longer to rearrange items.

A schematic of a warehouse floor. Shelves with fast-selling items are
indicated in red. Blue squares show slow-selling items. Robots rearrange
the shelves to keep the fast-selling items at the perimeter, close to
packing stations.
Credit: Kiva Systems

Kiva's system can adapt in other ways as well. If someone orders red
pens that happen to be stored on the top shelf of a shelving unit, the
system software directs that unit to a tall worker who can easily reach
the pens. If red pens become hot sellers, the system will instruct
stockers to stop putting them on the top shelf and start putting them on
the middle shelf, where everyone can reach them. Also, the
"peanut-butter and jelly algorithm," as Mountz calls it, tells stockers
to place items that are frequently bought at the same time on the same
shelf. This can be changed as demand shifts from day to day, or between
the summer and Christmas. Around Christmastime, the system can also
direct robots to stations with the appropriate style of wrapping paper.

For Walgreens, the software will need to keep track of another
parameter: expiration dates. It will ensure that items that can go bad,
such as certain cosmetics, are sent out in the order that they're
stocked. (Walgreens will use the system to supply its store, not to fill
orders from consumers.)

Kiva's adaptive software is the key to the system. The hardware isn't
remarkable. The robots are small, wheeled boxes short enough to slip
under a shelving unit and lift it up. The navigation system is simple,
involving stickers on the floor, optical sensors, and Wi-Fi connections.
The software prevents the robots from running into each other, and it
keeps track of products on the ever-changing warehouse floor. Infrared
sensors warn the robots of unexpected objects in their path--such as a
box or a broken robot. Algorithms then kick in to reroute robots around
the obstacle. The shelves themselves have lights that tell workers where
to stock items, or where to find them in order to pack them. Bar-code
scanners register when workers have packed an item and signal the next
robot to move into position.

Kiva engineers are working on ways to improve the system. Right now, if
a robot breaks down and maintenance workers need to go out on the floor
to retrieve it, they virtually "rope off" the area in the warehouse,
telling the software to route robots around the area. Mountz says that
the engineers are developing a wireless device they call the Moses badge
that will allow workers to walk safely among the shelves. The badge will
signal the mass of robots to part and allow the workers through.

Rodney Brooks, professor of robotics at MIT, says that the Kiva system
is a "very interesting" application of robotics. "It is increasing the
productivity of people by having robots do the easy tasks and letting
people do the hard tasks," he says. "At the moment, it is incredibly
hard for robots to manipulate varying objects. So Kiva leaves that to
people and lets the robots do the relatively easy task of moving
something from one place to another." Eventually, Brooks says, robots
may be able to handle all the tasks involved: "Don't expect the current
hard tasks for robots to stay hard forever."
Copyright Technology Review 2007.