[Animats]

There are systems like that, but they're much more expensive than the Kiva system. Kiva just needs a standard, simple mobile robot base and a lot of sheet metal shelving units. It's reliable, because no one robot is essential; if one fails, another one takes over. All you need is a big warehouse with a flat floor; there's not a lot of custom mechanical engineering of conveyors and tracks.

The Kiva system is low-maintenance and low-skill. All you need on-site is someone to replace batteries and tires and clean the things; anything more than that, just ship the robots back to Kiva HQ in Massachusetts. No need for any on site engineering talent or on call maintenance.

Dispensing racks for picking systems are complex, expensive, and have single points of failure for each item. They're essentially huge vending machines. They do exist, though.[1]

Amazon has an R&D program under way to automate the picking process where the Kiva shelf unit reaches a human. They have a competition for robot picking.[2] The prize is $26,000 for a solution that will save Amazon billions.

[1] http://www.ssi-schaefer.de/en/conveying-and-picking/automati... [2] http://amazonpickingchallenge.org/