A real robot, in my house?

Robots get a lot of attention – between the robot wars on cable TV, news articles on police and military robots, and the occasional robot vacuum or lawnmower in a mail order catalog there’s a lot of folks out there who are taking credit for making useful (or at least really cool) robots. Are we finally able to buy a real-world robot appliance that does what it’s supposed to do?

I have to admit that every time I’ve seen a robot vacuum in a catalog I’ve been sorely tempted to buy one. But I know the technology is new, and my non-palatial house probably isn’t suited to a device that clearly needs wide-open spaces. As for the lawnmowers, well, at over $1000 that’s a pretty tough nut to swallow. Still, the prospect of technology at my beck and call, particularly to do menial chores reliably is really heady stuff.

Then we were at Home Depot the other day and I saw a display for Roomba. Now I’ve seen these units in catalogs lots of times, but I always put it in the expensive-gadget-that-probably-doesn’t-work category and moved on. Seeing it in person, however, changed things. Looking at this thing zipping around a small section of hardwood floor really captivated me. My wife scoffed, took firm hold of my arm, and led me away.

The next day I went out and bought one while my wife was at work.

I fully expected to unpack the thing, see it zip around for a bit, and then watch as it failed to deal with the geography of our little house, gagged on a carpet or as some other fatal flaw revealed itself only to have to return it. After a few days, it’s still a keeper. The thing actually works. But, one has to understand Roomba’s mission in order to see it in the proper light.

Will it totally replace our regular vacuum? Nope. It doesn’t really remove the need to vacuum by hand occasionally either. When you look at the unit, and more importantly when you hear it, it’s obvious that it has limited power. A regular vacuum’s power is limited only by the circuit rating of the nearest wall socket, and the manufacturers know that you’re not vacuuming every day, and that when you do vacuum you expect the machine to pick up all the dirt in one pass (or at most two). Therefore, a regular vacuum has got gobs of power.

Roomba, on the other hand, is really designed with a different use in mind. It’s not intended to give the super-sucking deep cleaning the old-style vacs deliver, it’s intended to be used every day. Not only that, but the way it ensures it has covered the entire room is through overkill. It doesn’t know where it’s going or remember where it’s been. Its intelligence is limited to making good guesses where to turn when it hits something, and detecting when it’s stuck and how to get unstuck. The rest of the time it’s just pinging from one obstacle to another. In the process of covering every spot, most spots get covered many, many times. From many directions. So, while a regular vac has to have the power to suck up the dirt in a just a few passes, from only one direction, Roomba dutifully goes over everything again and again. In this kind of scenario, Roomba’s limited power has a lot of chances to get the dirt.

The result is pretty much the same as with a big vac – this little guy picks up the dirt. As it happens, my skeptical wife made me Swiffer a room that the Roomba had just cleaned to see what it missed, and while the Swiffer cloth was not pristine, it was still pretty darn clean. The real value isn’t in Roomba’s ability to clean as well as you would with a regular vac, although the manufacturer claims it does. The real value is that it will clean when you don’t want to – you can turn it on as you walk out the door to go to work – every day.

I had figured I’d have to spend a lot of time “Roomba-proofing” the house, but that wasn’t really the case. Yes, papers and other small items have to be picked up, but it bounces around shoes, books and other larger items just find. Cords are also not much of a problem as long as they’re near a wall. Rugs with tassles on them are another story, but no vacuum deals with them well.

Earlier I said that Roomba just bounced from one obstacle to another, but really it’s much more sophisticated than that. I looked at a recent patent awarded to iRobot, the folks who make Roomba, and found that the unit not only can tell which side it impacts an obstacle on, but at what angle. Depending on the angle, and what it’s hit recently, Roomba decides whether to follow an edge (which might carry it into another room) or rebound normally. If it doesn’t hit anything in a given distance, it turns as a guard against slipping wheels. The combination of switching between rebound and edge-following mode, along with varying the angle of rebound are some of the things it does to ensure complete coverage of a room or set of connected rooms.

There are more expensive vacuums out there that actually map the room, and keep track of where they’ve been, and make a sensible path around the room. That’s the way some folks expect Roomba to work – because it makes sense from a human point of view because it’s efficient. Efficiency on the robot’s part is irrelevant. Efficiency of my time and money is what’s important. I think the beauty of Roomba is that it does its job with minimal intelligence and no mapping, which keeps it’s price reasonable. If I don’t have to wait for it, I don’t care how long it takes to do the job so long as it gets done. So in the end Roomba doesn’t save me any less time than a more complicated model would.

To me, that is what really useful robotics are all about. We don’t need machines that do exactly what we do, we just need them to do what we need done.

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