If you ask a robot scientist why his industry is so interested in cleaning our floors, chances are he'll mention the "three D's." Robots, it turns out, are best suited to replacing humans in jobs that are dirty, dull, or dangerous. Sweeping, vacuuming, and mopping fit the first two D's, and depending on your dog's diet, perhaps the last one as well. It's no wonder, then, that the world had such high hopes for the Roomba, the autonomous floor-cleaning robot that first went on sale in 2002. The Roomba was built by iRobot, a company best known for its bomb-disposal machines —in other words, excellent preparation for designing a tool to help frat brothers clean up after keggers. The Roomba quickly became an icon— nerds hacked it, cats loved it, and lonely people grew to consider the bot something like a pet. There was just one problem: When it came to cleaning, the Roomba sucked, and not always in a good way.
The Roomba's creator, iRobot, has always been upfront about this. The company bills the machine as a complement to manual floor maintenance, not a replacement. Getting a Roomba is not going to eliminate the need to sweep or vacuum your house—it's just going to let you do so less often or assuage some of your guilt at never doing so at all. In my experience, though, the Roomba has struggled to meet even this low bar. When I first got the robot in 2007, I loved it—if I used it per the company's directions, it cleaned up quite well. But over time, I grew to resent the machine. The Roomba, I found, was neither very bright nor obedient. If I didn't clean up the room before I turned it on—moving chairs, setting up "virtual walls" to restrict its movements, removing errant video cables and other wires—the Roomba would either get stuck or wander around aimlessly. I've taken to using the Roomba less and less—it's both quicker and more effective to get out a broom or Dustbuster.
Perhaps because of these flaws, iRobot's recent Roomba sales haven't been great. Home robot revenues fell in 2009, and domestic sales have been flat over the last few years, with most growth coming from an international expansion. At least in America, it seems we've soured on the Roomba.
Despite the Roomba's problems, competing robot cleaners haven't done very well; the Roomba remains the best-selling robotic floor cleaner in the world. In the last few weeks, though, I've been testing two new robots that could well threaten its preeminence. One of them is a vacuum cleaner called the Neato, which sells for $399. (The Roomba, by comparison, runs from $199 to $599, depending on the model.) The other, the Evolution Mint, is a $249 sweeper and mop—that is, it works on tile, wood, and other hard floors, not on carpet. I found both the Neato and the Mint to be pretty good cleaners. In my tests, they seemed to get floors cleaner—and required less regular maintenance and pre-cleaning—than the Roomba. Still, neither one fulfilled the dream of those of us who loathe housework—they couldn't clean well enough to eliminate the need for human help. Like the Roomba, they're both supplements to a broom, a mop, and a vacuum, not a replacement.
To understand what makes these new gadgets superior to the first generation of robo-cleaners, it helps to understand how the Roomba works. The iRobot company was co-founded by Rodney Brooks, an MIT roboticist who has long been obsessed by the movements of insects. (He's profiled in the brilliant Errol Morris documentary Fast, Cheap & Out of Control.) In the 1980s, Brooks provided a key insight to the emerging field of artificial intelligence—instead of trying to create machines that think the same way you and I do, he argued, we'd have more success creating machines that operate according to simple reflexes, like insects. That's the Roomba's operating philosophy. As the book Hacking Roomba explains: "Roomba has no room map or route plan. It has no overall view of what it is doing. Instead it functions much more like an insect: going toward things it likes (dirt, power) and away from things it dislikes (walls, stairs), moving in predefined movement routines while occasionally and randomly jumping out of a predefined routine."
The problem with this approach, Roomba's competitors say, is that it's wasteful. The Roomba cleans a floor the way you would if you were blindfolded—it moves in one direction until it hits something, then turns in another direction and moves until it hits something else. Eventually it cleans every part of the room—but the anti-Roomba crowd claims that it does so unevenly, going over some parts of a room many times while cleaning other spots just once. A more systematic approach could yield greater efficiency: If a robot cleaned each part of the floor just once, it would have a lot more battery power to clean more forcefully and could clean more quickly, to boot.
That's the theory behind both the Neato and the Mint. "We clean your floor the way a Zamboni would, or the way you would," says Max Safai, the CEO of Neato Robotics. The Neato uses several different sensors to create an internal map of a room. Based on this map, it will first clean the room's perimeter before going back and forth within the perimeter in a systematic way. To see what I mean, watch this clip of the Neato tooling around my dining room:
Because this back-and-forth pattern is more efficient than Roomba's blind walk, the Neato can afford to pack a much more powerful vacuum cleaner onboard. As a result, the Neato left a discernible, just-cleaned pattern over my thick-pile rug—the sort of pattern I get when I use an upright vacuum, but that the Roomba could never achieve. What's more, because the Neato creates a map as it goes, it always knows where it is. This allows it to go from room to room, cleaning each area before it moves on to the next one. When it runs low on power during its cleaning mission, it can pilot back to its charging base and then start back up again from where it left off. Safai says that after forthcoming software updates (the Neato has a USB port that allows you to install new firmware), it will be able to perform a couple of more tricks—remembering and avoiding places where it's had trouble navigating and allowing you to schedule cleaning certain rooms on certain days.
Still, I noticed a few problems with the Neato. First, it was loud—it sounds like an angry jet engine on startup, and it was hard to tune out even if it was in another room. Second, the Neato sometimes missed spots. One of my tests was to throw rice on my rug and let the Neato run free. When it was all done, all the rice was gone except for a single, five-inch-long line of grains. This confirmed what Nancy Smith, iRobot's vice president of marketing, told me about the flaws of Zamboni-like systematic robots—because they clean each part of the floor just once, they sometimes don't do a thorough job in the filthiest places. The Roomba, by contrast, would probably have gotten that rice, because it likely would have gone over the same spot many times from different angles. What's more, the Neato sometimes got stuck on wires (albeit less often than the Roomba), and—again like the Roomba—had trouble docking in its docking station. (About half the time, the Neato navigated almost all the way to the docking station before getting stuck.)
Here's a video of the second cleaner I tested, the Evolution Mint:
As you can see, the Mint is a lot smaller and quicker than the Neato (and the Roomba, for that matter). That's because it has no vacuum. Instead, it sweeps the floor with the help of a washable microfiber pad or a Swiffer that you can attach to the Mint's cleaning foot; to mop, you use a wet cleaning pad (also washable). Like the Neato, the Mint is a systematic robot that constructs an internal map of a room. In addition to onboard sensors, the Mint is also aided by "celestial navigation," which is enabled by a small transmitter that you set up somewhere in the room. The transmitter shoots infrared signals on to the ceiling, and the robot determines its position by triangulating over those signals—essentially the way GPS works. (Ironically, iRobot has a celestial navigation patent, but the Roomba doesn't use it.) The Mint also lacks a docking station, which means that it can't start up and charge itself; you've got to set it up in every room you want it to sweep.
I loved the Mint. That's because it was fast, quiet, and the most straightforward of the three robots. In particular, the Mint did something simple that neither the Roomba nor the Neato can do: clean a single room fully, and then stop, without my explicit instruction to do so. I found myself using the Mint every night after cooking dinner—it could mop the kitchen while I watched TV in the next room, which I couldn't do with the too-loud Neato or Roomba. Also, I noticed that the Mint was a lot better at steering clear of obstacles than its bigger, noisier rivals. It was also—and this is no small thing—the cutest of the three robots.
The Mint is not for everyone; don't get it if you've got a lot of carpets in your house. And because it sweeps but doesn't suck, it's not good for cleaning up bigger messes—if you spill cereal, you'll have to reach for a broom or a Dustbuster.
Despite their limitations, the Mint and the Neato both represent worthwhile efforts to improve floor-cleaning tech. Even iRobot agrees; when I called her to ask about the rivals, iRobot's Nancy Smith told me that the company welcomes competition. As Wall-E taught us, there's nothing sadder than a lonely robot trying to clean up an entire planet. Now, at least the Roomba has company.