The manual system isn't that different from the Sears "schedule system" introduced in 1908.[1] Note the line "pickers don't necessarily pick items for a single or even complete order." That's crucial. Orders are split apart and combined pick lists generated. Picked items then flow towards order assembly stations, which Amazon calls "sort". At any one time, some maximum number of orders are in progress, limited by the number of output boxes at order assembly. Amazon does this with computers; Sears did it with clerks and pick slips, with Sears giving each order an assembly bin for a fixed number of minutes.
Separating picking from order assembly and inserting a sort phase reduces the order of the problem. Picking N orders from M items individually means O(N × M) cost, because as inventory becomes larger, the pickers travel more distance. With separate picking and assembly, performance is something like O(log(M) × N) cost, because each picker works in a limited area. That was Sears' big breakthrough.
[1] https://news.google.com/newspapers?nid=1734&dat=19721006&id=...
I think you're right that it would be more energy efficient -- since a human weighs less than a rack full of goods.
But energy, compared to the other costs, is a fairly small component of costs.
The bigger question is whether a person is cheaper than a machine.
A few years ago before Amazon bought Kiva, they would sell a complete setup for a large warehouse for $15-20m for 1000 robots. This included a lot of setup, but even if we assume it's just 20m/1000 robots = $20,000 each.
So for $20,000 you can get a robot that will work 24/7 for a few years. Lets pretend the kiva robots are completely junk after 3 years. That's under $7000/yr.
Obviously, that's going to be tough to beat with a human. But for comparison, lets assume a person gets paid federal minimum wage ($7.25/hr), there's no overhead, no management, healthcare, never gets sick, etc. That equals $15000/year. But that's only for 40 hours a week x 52 weeks/year. So really, we'll need 3 people.. so $45000/year. (EDIT: I forgot about weekends, which is another 48 hours. So really, we need 4 people, or $60,000/year.)
Considering that humans are so much more expensive than a kiva robot, the increased energy compared to segways doesn't really effect the outcome. It's clearly cheaper to use robots and simply pay for the increased energy usage.
(Any human fitting this definition is also spherical and frictionless, i.e., existing nowhere outside of physics textbooks.)
Bonus points: this remains true if one does not value money but one instead counts costs totally in carbon credits, which is one of those things that the environmental movement passionately believes and yet doesn't spend much time thinking of the implications of.
To fulfill an order with Kiva, a human stands at a ship station (boxes, label printing, tape) near a fast path (door, belt) to outbound. Shelves are brought, the human picks the item from the shelves and assembles the order. That's putting the humans in the loop where robotics is harder/more expensive. Your hard fulfillment rate limit is then the time it takes the human to pick and assemble the order, plus whatever time it takes the robots to bring the shelves over. This scales gracefully (install more robots until the hard latency of order fulfillment becomes robot travel time from the farthest shelf to the human, plus human time) -- robots scale with the number of shelves, humans scale with the number of fulfillment stations.
To fulfill via Segway, you tie up a human for the entire travel time between station and the traveling salesman problem of order picking and back. Or you do as Amazon was doing in this article, and split pick and pack and allow for subdividing orders between pickers, and so on. This works (obviously) and the segway approach would likely improve fulfillment speed for pickers. But it does not save operating expense (headcount).
The shelves could be modified to be like automatic wending machines. The robots could just go to the shelf and the shelf will dispose the correct item to that robot. Then the robot goes to the next shelf for that order and collect all the items required for the order from different shelves and return to the packer.
The packer need to only arrange the items in the final box.
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/
Sorta crazy they're using robots & still need to hire that many people.
http://www.chicagotribune.com/business/ct-amazon-joliet-0811...
And what is this pallet land ? what's the benefit?
Pallet land is the part of the FC for products we carry in large quantities (i.e. enough to fill a pallet, quarter pallet, or half pallet). Pallet land is just a nickname we give part of the pallet area. We also have a 3-story rack area full of pallets (at my FC). Some items we have on pallets include some Starbucks, Sonicare, and Darth Vader costumes (omg we have so many).
> Aside from a few exceptions, most items are randomly stowed. The stowers all have a rate, and because of that, will find whatever space fits their needs.
It was by far one of my favorite schedules. I rode my bike to work and that was about 45 minutes each way and when you add in the time it takes to get ready for work it was nice to only have to do that 50% of my days. And with four day breaks I was able to really get into projects or go camping for a long time.
FWIW, The Infrastructure Observatory is working on more tours like this one, mostly in the NYC area. If you want to get involved (or have an idea for a tour that we should organize), get in touch at http://infraobservatory.com or @NYInfraObserve on Twitter.
-Spencer
Bonus quote: "Our tour guide used an iPhone, but claimed he’d use a Fire if he wasn’t locked into his carrier."
I wished they would add a diagram, even if it's just hand-drawn. It's would have been much easier to visualize, especially the detailed parts.
Also the naming is sometimes inconsistent across the different authors. e.g. Sometimes folks are called "associates", sometimes "sorters". It got confusing quickly. Would be nice if the naming was clearer
So, you'd think there would be some logic to how the items were distributed and not just the whim of the associate. (Or maybe that's good enough.)
"Wow, this file is really popular! Some tools might be unavailable until the crowd clears."
