The Coming (Cleaning) Robot War

The iRobot Roomba currently dominates the home cleaning robotics market, but one robot -- the Mint -- could change all that with a bigger brain, quieter running and by using everyone's favorite microstatic cleaning cloth.

By Erik Sofge
March 11, 2010 11:21 PM

If humans cleaned floors the way robots do, they would be fired, or rushed to the hospital. Imagine a janitor slamming into desks and chairs and walls, vacuuming the same corner five times, yet always missing that one dust bunny by an inch. You would not find this person cute, no matter how be beeped and shuffled around. You certainly wouldn't go bragging about his autonomous capabilities and learning algorithms.

There's hope, though. The robot swishing across the floor in front of me is no genius, but it might be the first cleaning bot that doesn't look completely lost. It's called Mint, and it's moving in a relatively neat grid across the Evolutions Robotics booth at the Consumer Electronics Show in Las Vegas. When it bumps into my foot, the robot doesn't fly off in a random direction--it heads back to the wall, shifts over a bit, and continues with its cornrows.

Mint's secret weapon is not a remarkably bigger or faster computer brain, but a new approach to indoor navigation. A small black cube, called a beacon, projects an infrared spotlight on the ceiling. Mint's upward-facing IR sensor uses that spot as a reference point as it maps out a room. Paulo Pirjanian, CEO Evolution Robotics, describes it as a micro-GPS system, with the IR spot acting as the robot's GPS satellite. For the most dedicated robot nerds, this might ring a bell--the technology is called NorthStar, and it debuted in WowWee's Rovio, a kind of rolling webcam that could be controlled remotely over a WiFi network. Evolution Robotics is typically in the business of selling components to other robotics companies, including vision-based sensors used in military UAVs. Designing and building a robot from scratch, particularly one with the cost constraints and compliance requirements inherent to appliance-grade products, was a drastic action. "We felt that the consumer robotics market is not growing fast enough," says Pirjanian, who's also a professor of artificial intelligence at USC. "We needed to take a leadership role in showing the way, and expanding the marketplace."

That's a roundabout way of saying that the world of consumer robotics is defined and dominated by iRobot, whose Roombas have sold in the millions, and has inspired countless imitators, but very little innovation. Instead of taking on the Roomba directly, Evolution went for the chink in iRobot's armor: wet and dry floor care. "iRobot attempted it with Scooba," says Pirjanian. "It was too expensive, too complicated, and it didn't work well."

If you don't care about robotics at all, this is what you'll hear about Mint: it uses wet and dry Swiffer pads. By harnessing the minor domestic miracle of disposable, microstatic cloth, Mint also manages to be light, quiet, and effective at cleaning. It also did away with the cleaning bot's biggest challenge: corners. The front of Mint is roughly the same shape as a Swiffer pad, letting it sweep directly into corners without employing a spinning brush.

Navigating a square-bodied robot, as it turns out, is more challenging than maneuvering a round one. Evolution falls back on NorthStar to help avoid constantly bumping into obstacles, as well as wheel odometry and gyros. But that IR spotlight is at the core of everything Mint does--the robot can continue to clean when it loses direct line-of-sight of the spot, sweeping under beds or even in other rooms, out to some 1000 sq-ft., so long as it can see the glow of the beacon's beam, a function called glow following. The result, Pirjanian says, is the ability to fully cover a given space three to five times faster than a Roomba.

Evolution isn't the only company at CES trying to one-up iRobot's autonomous navigation. Neato Robotics' half-square, half-rounded vacuum bot, the Neato XV-11, uses a top-mounted laser rangefinder to do virtually all of its navigating, scanning the room before setting out to clean it. Again, the robot's makers claim a major boost in speed compared to iRobot--up to 4 times faster, in this case.

From a business perspective, Neato and Evolution aren't likely to make much of a dent in iRobot's market share. But on a technical level, the gauntlet has been thrown. Despite the Roomba's rich intellectual history--its behavior-based AI is a direct descendant of CEO Colin Angle's collaboration with pioneering MIT roboticist Rodney Brooks--as of 2010, the algorithms are showing their age. And while Neato's approach is more of a shift in sensor priorities than anything else (iRobot uses lasers, too), Mint's NorthStar IR beacon-based approach, on the other hand, has all the markings of a game-changing indoor navigation technology. Evolution has tested NorthStar on robotic toy prototypes, with cars racing around a virtual track (based on a map of the room), and detecting and interacting with other toys fitted with IR lights. "We call it an appliance as often as possible, but when you look at the wheel encoders, the IR navigation, the core technology, we think Mint is the next generation of robots," says Tom Dooley, Evolution's VP of Products, and former head of development for Lego Mindstorms. Dooley deflects questions about going head-to-head with iRobot, pointing out that the Roomba and the Mint have very different jobs. There are key design differences, too--Mint runs for four hours per charge, but has no base station for recharging, since it's intended to be tucked away in a closet after use, like any other cleaning appliance. And robotics is generally a clubby sort of business, more academic than cutthroat. But as for Mint's NorthStar-empowered brain, Dooley has no doubt that its smarter, and far more efficient than the Roomba. "If that's the message iRobot gets from this article," says Dooley, "I'm fine with that."

Post a comment

Featured Video