February 17, 2010      

No one has yet come up with a reliable, inexpensive device willing to do the dishes or the laundry. However, the availability of robotic lawn-mowing equipment continues to increase, with steady improvements in technology and price. Despite advances, however, the labor-saving technology homeowners still turn to most often is a relatively old-fashioned solution: a spottily reliable teenage boy. But Robotics Business Review expects that to change over the next decade, as robotic lawn mowers better address navigation and obstacle-avoidance issues, as well as safety concerns.

A Massive Consumer Market

Many people enjoy tending their own lawns, and take pride in the results. Of the 115 million households in the United States, 70 percent did some work in the yard or garden themselves during 2009, rather than hiring a landscape service or skipping it all together, according to a widely respected annual survey released by the National Gardening Association.

That 70 percent—61 million households—spent an average of $444 on lawn and garden care during 2008, for a total of $36 billion. Three-quarters of them planned to spend the same or more during 2009, according to the report, which was released in July 2009 and focused on spending the previous year.

In addition, of the $8.5 billion Americans spent on power lawn and garden equipment in the United States, 62 percent went for equipment designed to cut the household lawn, according to industrial research firm the Freedonia Group. Thirty-seven percent of that—$3.15 billion—was spent on new lawn mowers. The rest was spent on turf and grounds-maintenance equipment, trimmers, edgers, replacement parts, and the like.

Compare that to the $5 billion ABIResearch predicts Americans will spend on robotic products by 2015 and you have an enormous overlap—one that could very well make the robotic lawn mower the Roomba of the next decade and free millions of reluctant gardeners from the least compelling portion of their landscaping routines.

While robotic lawn mowers are not nearly as common or as widely accepted today as iRobot’s Roomba vacuum cleaner, they have the potential for equal growth. Launched in 2002 to great fanfare and poor initial sales, the Roomba eventually convinced consumers it could operate as promised—though iRobot’s engineers had to overcome spotty performance problems with its guidance system, dirt container, and battery life. In January, iRobot announced that total sales of the Roomba vacuum-bots had passed 5 million units.

To achieve similar acceptance, makers of robotic lawn mowers will have to overcome the inertia of a market that has yet to incorporate digital technology into the products in any significant way. They will also have to overcome consumer fears: An out-of-control robotic lawn mower is much more dangerous to children and pets than a rogue floor sweeper, for example.

Operating outside the house rather than inside—while not a game-changing difference from the point of view of the engineers designing the guidance systems—is a tremendous difference to consumers. Having to hunt down a Roomba that gets stuck under a couch and runs down its battery is much simpler than wondering if a robot landscaper missed a turn by the sidewalk, rolled into the street, and was run over as it wandered aimlessly down the road looking for its guidance markers.

The potential benefit to consumers, however, is more than sufficient to generate a profitable market for manufacturers. Even now, when the performance, efficiency, and lifespan of robotic mowers is open to question in the minds of many consumers, wire- and GPS-guided units are common enough to be featured on Amazon.com—many at steep discounts off the list prices.

The Commercial Market

Commercial grass cutting, spraying, and turf maintenance have a far more immediate and direct benefit for the purchaser than consumer-oriented robotic lawn mowers. The cost and complexity of the systems themselves are tremendous barriers, however. Not only must manufacturers develop systems with extremely precise navigation and cutting capabilities, the systems must be able to detect and avoid unexpected obstacles, ranging from inanimate objects that could damage the equipment, to humans or animals that could be harmed themselves.

Given the labor-intensive nature of large-scale commercial landscaping and turf maintenance, Robotics Business Review sees very little chance that the potential market for autonomous or semiautonomous lawn-care equipment will vanish due to disinterest from customers.

There is the chance that genetic manipulation of grasses and weeds will produce turf that requires less water and less maintenance than is currently the case. That process is already far more developed and widespread than autonomous turf-maintenance equipment. The size and complexity of the challenge are also much greater, however. It is unlikely genetic manipulation will deliver maintenance-free lawns and golf courses soon enough—and effectively enough—to significantly reduce the market potential of robotics for commercial lawn care.

Technologies Involved

Today, autonomous or semiautonomous lawn-mowing equipment requires a series of systems and technologies that, in many cases, are not sophisticated enough to handle the job required of them. In other cases the technology exists, but must be refined to the point that it can be used to allow robots to operate largely unsupervised without endangering humans or the lawns the robots are designed to maintain.

The biggest problem is navigation, followed by obstacle avoidance.

  • GPS. Satellite-based navigation signals provide contextless orientation and directional information; specific data about obstacles, area to be covered, and hazards such as holes or rocks must be programmed by the operator.
  • Wire. Wire with low-voltage charge is buried along the perimeter of the property to be mowed. A magnetometer in the mower detects the charge and recognizes it as a barrier.
  • Beacon. Infrared, ultrasound, or other directional broadcast can identify a corner or barrier through which the unit should not pass.
  • Radio Control. One-to-one control of a mower by a human operator who handles navigation and obstacle avoidance, using remote controls similar to those on higher-end remote control cars, boats, or planes.
Safety/Security/Obstacle Avoidance
  • Laser-Vision System. Uses low-power lasers to scan the area for unexpected objects. Requires an existing map of objects in the area.
  • Bumpers. Touch-sensors that allow the unit to detect obstacles and stop.
  • Security/Safety Pass. PINnumber, password, or security dongle is required to start the unit; designed to keep children and thieves from starting it.
  • Orientation Sensor. Allows the blades to spin only when the unit is on the ground and the blades are not exposed.
Risk of Injury

Every year between 80,000 and 100,000 people in the United States are injured badly enough by a lawn mower to receive treatment in an emergency room, according to a report from the American Academy of Orthopaedic Surgeons. About 10 percent of the injuries are to children, one-quarter of them younger than 5 years. Most injuries involve hands or feet coming into contact with the blade, or from projectiles—rocks or other obstacles thrown after collision with the blade.

Many of the most serious injuries to children come from those falling from an adult’s lap on a riding mower—a situation very similar to a collision between a robotic lawn mower and a child.

Most commercially available robotic lawn mowers include bump sensors, blade arrestors, and other safety features designed specifically to avoid such injuries. Given the potential for harm and for lawsuits charging negligence or poor design, investors should investigate safety features as a key technology in making a particular design successful.

View of the Markets

From the standpoint of performance, efficiency, and engineering, the commercial market for robotic lawn care is far more interesting than the consumer market. Return on investment is easier for a country club with 36 holes worth of lawn maintenance, or a groundskeeping department responsible for landscaping commercial buildings or developments.

Landscaping generated $44.7 billion during 2008 for residential maintenance alone—a total that’s been growing at 10 percent per year for the last five years, according to a National Gardening Association report.

Lawn mowers for that market tend toward stand-on models with zero-turn radii that allow them to reverse direction without having to go back and cut the part they missed, as they often run at speeds higher than high-end commercial mowers, have cutting surfaces 45 to 50 inches wide, and price tags between $3,000 and $10,000. Leading manufacturers include Toro, Gravely, and Dixie Chopper, whose Xcaliber model is billed as the fastest commercial lawn mower available. It has a 74-inch-wide cutting deck, cutting speed of more than 15 mph, is rated to cut 8.9 acres per hour, and costs $11,400, though for that price you also get a 12-volt adapter that will power your iPod or MP3 player while you trim away.

Farther up on the scale are ultra-high-volume cutters and other extreme mowing machines designed to cut golf course fairways for the nearly 16,000 golf courses in the United States—maintenance and upkeep for which generates $76 billion per year, according to Golf 20/20, the business-analysis wing of the World Golf Foundation, a consortium of golf course owners, developers, and suppliers.

Fairway and greens clippers are essentially large tractors—from companies such as John Deere, Toro, Hustler Turf, or Jacobsen—with three or more separate cutting units, cutting swathes as wide as 16 feet, four-wheel drive, high-horsepower engines, the ability to angle cutting surfaces separately to match the pitch of uneven or sharply sloped ground, the ability to cut up to 16.5 acres per hour, and price tags often north of $60,000.

Taken as a whole, that is a great deal of technology to replace with remote-controlled or robotic versions. However, golf course owners are accustomed to paying tens of thousands for good equipment and can tell whether the time saved with automation justifies the investment. Robotically controlled units can provide not only cutting, but spraying of fertilizer and insecticides—which is as time-intensive as mowing but far more dangerous for human operators exposed to the chemicals. This is an important feature as studies of golf course maintenance workers have shown cancer rates far higher than the general population.

Manufacturers such as Dvorak Ltd. and Precise Path Robotics have leapt into the market enthusiastically, but not with the immediate goal of producing autonomous long-distance mowers.

Dvorak’s Spider is a remote-control cutting unit designed to handle the tough spots—cutting under thick brush and on steep slopes that would otherwise require 25 times the man-hours for workers with handheld trimmers, according to the company’s literature. Though the work is automated, it requires one-to-one supervision and control. The operator walks near the cutting unit and directs it with RF remote controls contained in a waist pouch.

PrecisePath’s RG3 greens cutters address a smaller geographic area but a higher maintenance requirement, using a series of infrared and ultrasonic beacons placed by greenskeepers to orient themselves and cut in a predetermined pattern. The greens cutters operate autonomously within their assigned areas, which must be marked to keep humans out of harm’s way. The cutters have four computers handling location, navigation, and operation, and are equipped to detect or avoid humans.

The RG3s must be set up and trained on the shape and dimensions of the green before they can operate, which takes about a day for an 18-hole course, the company says. Once operators have run it across a green to preserve its shape in memory, the RG3 can cut using only four beacons for guidance. After it is finished, greenskeepers pick up the RG3 and beacons and move on to the next green, shifting that part of their jobs from greens cutting to chauffeuring robots from place to place.

RG3s take about 10 hours to charge and they run for three, during which they can cut about 53,000 square feet, the company says.

The units are not yet commercially available; they completed their second round of customer tests—a summer-long stint cutting more than 3 million square feet of greens—in September 2009. An updated model, with better weight distribution, better motors and controllers, and more cutting capacity, will go into a third round of tests early in 2010.

More broadly capable high-capacity cutters are under development at both major manufacturers and in universities, though commercial development even to the point of customer testing is still several years away. Toro, for example, manufactures a line of consumer-oriented robotic mowers and helps fund developmental research by Sanjiv Singh of Carnegie Mellon University’s National Robotics Engineering Center. Singh is experimenting with a global positioning system (GPS) on commercial lawn mowers, using laser scanners to detect obstacles and satellite navigation to control orientation and course.

That approach is promising because it addresses both navigation and unexpected obstacles, but the cost of building and integrating a GPSis still too high even for commercial turf maintenance. In addition to systems on the mowers themselves, a successful sat-nav-driven robotic mower would require that the golf course or other territory be mapped very precisely using a geographic information system (GIS) and the placement of beacons or other navigational aids around the grounds to verify its location.

Both the mapping and navigational systems would have to be more sensitive than the 3- to 5-meter approximations most commercial sat-nav systems can deliver.

Design Goal: Repairability, Not Perfection

Investors interested in companies designing robotic mowers for consumers should consider the following: Lawns in residential areas, particularly lawns that are large or are in wooded or isolated areas (typically owned by those who can afford high-end convenience products), are not regular or predictable environments. Even lawn mowers pushed by humans frequently run into obstacles, tangles, steep slopes, gummy material that can clog the blades, or dust that can choke the motor. Manufacturers designing mowers to cut lawns that are flat, small, and unobstructed are addressing a tiny portion of the market (though it is exactly the same population to which the Roomba first appealed: people with no time to sweep, but not much mess to clean up either).

Unlike the commercial market—where the scale of the job, time expenditure, and risk from imperfectly operating equipment are all much higher—the consumer market is relatively forgiving. For example, even after seven years of refinement, such as improvements in navigation, pattern development, and dirt management, the Roomba is still far from a zero-maintenance dream machine. Any home larger than a room or two, or any room that includes furniture that can trap a small bot, is both a challenge and a threat to the Roomba. Even functioning perfectly, it often requires assistance to find its way back to the charger, unclog its sweepers, or get out from under the couch.

The genius in iRobot’s refinements is not that the company eliminated the chance that a long string, a clump of dog hair, or other hazard could derail the Roomba. The genius is in how easy the robot is to repair. The guide wheel pops out, the sweepers unclip, the dust collector pops out, and the rotating brushes can be manually spun to free them from a tangle, or easily unscrewed to fix more severe tangles.

To be successful, any robotic lawn mower designed for consumers must be engineered to be repaired just as easily. That is a far greater challenge for a unit designed for an environment that may include large sticks, play equipment, pets or wild animals, and surfaces far more uneven than even the most complex mesh of area rugs.

Robotic lawn mowers must also be hardy enough to handle dust, dirt and mud, large clumps of wet grass, and leaves. They also must be able to withstand rain, cold, ice, infrequent charges—most current or developing designs use electric rather than internal combustion engines—and living outside the house in a shed or carport with minimal shelter from rain, snow, sleet, and all the other meteorological indignities that come along even during seasons the lawn mower is put away.

What robotic lawn mowers do not have to be is completely autonomous, autodidactic, and self-scheduling.

The Roomba works for those who love it because it does its work—slowly and over what would be an unreasonably long period of time for a human—over and over again until it gets the job right (as far as it can tell). A Roomba can sweep a given room far more often than a human would, and the result is better for both human and Roomba than if it were barely used at all and had to sweep up all the troublesome bits at the same time rather than one or two every time it works the room.

Lawns should not be mowed in a similar manner, however. For many people, a lawn badly mowed or partially mowed is worse than not having it mowed at all. For the majority of homeowners, having a robot mow the lawn would be acceptable only if it could complete the job on the same day. Mowing half today, a quarter tomorrow, and three-quarters the day after that—the volume depending on how wet the grass is and how quickly it wears down the battery, perhaps—is unacceptable.

Many homeowners would be perfectly happy to supervise, or even remotely control a lawn mower, even if they would refuse to do the same thing for a Roomba. Still others would also be happy to put out beacons, barrier wires, or even low bump fences if necessary to keep a robotic lawn mower in the right area. It’s not unheard of for Roomba owners with dead batteries in their artificial-wall beacons to pile up pillows or chairs across doorways to keep the robot from wandering into the wrong room. The principle is the same for lawn-mowing robots.

In a 2009 survey of 2,200 consumers, J.D. Power rated Honda as the most-reliable maker of walk-behind mowers, followed by John Deere, Craftsman, and Toro. Honda rated highest in overall satisfaction despite the need for maintenance and occasional minor repairs. Thirty percent of owners reported having a problem with the mower during the first two years of ownership; clogged grass discharge was the most frequent culprit. The survey showed that price is the most important factor to consumers trying to decide on a product, followed by durability.

Currently available robotic lawn mowers suffer in price—all are very expensive compared with most standard mowers—and have the same (or higher) risk of common clogs and breakdowns that nonrobotic mowers have.

Barrier-Free Market Segmentation

In the commercial market, the expense and complexity of autonomous systems create a barrier to entry between market segments. The same controllers and navigation that allow a greens cutter to operate effectively may not adapt easily to an automatic sprayer or fairway mower, for example.

In the consumer market, however, differences in the task required primarily involve the size of the yard or slope of the ground, not the component tasks involved. Market segments will be differentiated largely by price, which itself will depend on the amount of involvement needed by the homeowner to get the unit working properly.

Current models all require a barrier wire around the yard. With improvements in GPS, low-cost beacons, and navigation software, higher-end models should be able to shift to wire-free implementations within two to three years. Technology cost reductions will give those manufacturers no more than a year before less-expensive models match that functionality, however.

Today battery life and mowing capacity are the greatest differentiators. The most expensive models claim ranges two to two-and-a-half times the capacity of lower-cost models, but at six times the price. Even above $10,000, the convenience consumers buy with autonomic mowing is partially illusion.

At either end of the price curve, homeowners have to monitor the units to keep them out of trouble with obstacles, children, pets, electrical cords, lawn furniture, hoses, sprinkler systems, and the other bric-a-brac of modern suburban lawns. Promises that robot mowers can operate unattended and untouched for weeks or months at a time ignore a large part of the chaos and changeability of most suburban lawns.

One additional factor to mention: Because grass is so heavy and battery life so important, most commercially available robotic lawn mowers mulch grass clippings using multiple or high-speed blades, rather than collecting clippings in a bag. Mulching mowers are believed to be effective at returning lawn waste as fertilizer; consumers for whom mulching is not an option may be forced to rake up after the robot, significantly reducing the convenience of the arrangement.

Current Approaches
Husqvarna Automower

The best-known of a little-known bunch, the Husqvarna Automower is a random-orbit mower that uses buried wires to find its limits, bump sensors to detect obstacles, large wheels to overcome rough or inclined ground, and batteries the manufacturer promises will enable it to cover half an acre at a time.

Friendly Robotics Robomow

Declared by the Guinness Book of World Records to be the best-selling robotic lawn mower, the Friendly Robotics Robomow is designed as a simple home appliance, not a complex robotic system. It includes self-scheduling software, a docking and recharging station, and a raft of safety features designed to make its operation foolproof. It relies on buried wires to identify its perimeter and borders such as flowerbeds, but it measures the distance every time it crosses the lawn and builds an area map it uses to make sure it covers the whole territory.

Earlier versions required operators to use a remote control to drive Robomow onto the lawn; more recent editions are marketed as entirely self-sustaining. List prices range from $1,100 to $2,700 (although Sam’s Club offered the lowest-end model for $915).

Kyodo America LawnBott

Kyodo America’s LawnBott also uses a perimeter wire, but it can operate without one in areas bordered by obstacles at least 4 inches high. Like Robomow, it has built-in bump sensors that redirect it when it hits a tree or other obstacle, scheduling capabilities, and a charging station it can find on its own for recharging. LawnBott is the buffest of the top three, billed as being able to handle a slope up to 30 degrees and a mowing area as great as two acres. Like the Robomow, it includes sensors that send it back to the charging station if it rains, and a blade arrestor that stops the cutting mechanism if it is picked up. List prices range from $1,400 for the LB1200 Spyder, which uses sensors that can tell when it is on grass to cut and doesn’t use a perimeter wire, to $4,000 for the two-acre Deluxe model.

BelRobotics BigMow

BelRobotics’ BigMow is aimed at the high end of the consumer market—with a cutting capacity listed as five acres and a list price nudging the bottom of $13,000. For that you get almost two hours of cutting time, sonar that detects obstacles higher than 15 inches, bump sensors that let it drive backward to maneuver around obstacles, and a self-cleaning, mulching mechanism that uses five cutting heads running at high speed to throw clippings clear of anything they could clog. It also uses a perimeter wire but, oddly, doesn’t include one. You have to buy your own.

The “lower-end” $8,400 edition, the ParcMow, has only three cutting heads, a less powerful battery, and a 2.5-acre rated capacity.

Toro iMow

Toro introduced the first version of its iMow in 2001, giving a test lawn what one Fortune magazine reviewer referred to as a “punk haircut” rather than a nice, patterned cut—“the horticultural equivalent of a drive-by slashing.”

It is not entirely clear if Toro still sells the iMow; searches on its site don’t turn up anything, though retail sites do seem to carry it. The Toro iMow is a red, rebadged version of the LawnBott RL500 Robomow, however, eliminating Toro as the sole major lawn-mower manufacturer with a robotic product aimed at consumers.

iRobot Competitive Threat?

Though it is far from the largest robot manufacturer, iRobot is the unquestionable big gorilla of the consumer robotics industry. It currently has no robotic lawn product. Introducing one would seriously disrupt what market exists so far. First, iRobot would expand the acceptance and potential audience for robotic lawn devices. Second, iRobot would become the mindshare leader overnight, as the robot manufacturer best known to American consumers. Third, it would disrupt the pricing structure for models already on the market. iRobot thrives on products that sell for less than $500—a price considered a bargain in the computer business, but quite steep for home maintenance or cleaning products. If it were to introduce a “LawnBa,” it is likely the price would be far less than existing products—under $1,000, almost certainly.

Without inside information, it is impossible to know, but there is currently little evidence iRobot is working on a lawn mower it can introduce in the near future. iRobot has been sporadically talking up its efforts to build a robotic lawn mower since at least 2006, and was outed by Engadget in 2008 for having filed for a patent on a Roomba-looking grass cutter. To date, however, nothing official has been announced or released.

CBSNews quoted iRobot CEO Colin Angle in May 2009 as saying that lawn mowing, cooking, window cleaning, and bathroom and tub cleaning were all good targets for robotic appliances, once it is possible to build manual manipulation into them at a price consumers can afford.

Still, there hasn’t been any progress announced on the lawn mower. In addition to the Roomba, the company has been successful in developing robots for the U.S. military, but has been less successful with the floor-mopping Scooba, the gutter-cleaning Looj, and the pool-cleaning Verro. It announced a new healthcare robotics division in November 2009.

It is possible iRobot has enough energy and development resources to build, manufacture, and market a new product for a market that is still developing and whose prices are still too high for most of its potential customers. It is not likely within the next 12 months, however.


While the market for robotic lawn mowers is small right now, it has the potential for explosive growth in the consumer sector and significant growth in commercial markets. Barriers currently holding the market back include relatively high prices for consumer devices, relatively low acceptance of devices beyond robotic sweepers or other comparatively simple devices among consumers, and the unwillingness of most consumers to buy high-ticket, labor-saving devices during a recession and period of high unemployment.

There are significant barriers to entry to both the consumer and commercial markets. Both require considerable R&D and engineering work, not to mention investment in marketing and sales channels. There is also a large risk that, as the market develops into one with a more significant dollar value, larger traditional manufacturers such as Toro, Honda, or John Deere could dominate over robotics companies. All three have extensive sales and marketing networks and established reputations for technology development, as well as pockets deep enough to buy an existing robotic lawn-mower maker or fund development of a competitor.

We at Robotics Business Review believe robotic lawn mowers will be much more common in 10 years. Prices for robotic systems will have to drop considerably if that is to happen, far enough to provide entry-level products in the $500 to $700 range, as well as products under $1,000 that support all the major functions of higher-end models, though without the speed, convenience, range, or precision of navigation and programming that will continue to differentiate high-end units from low.

In the commercial sphere, robotic mowers will continue to be niche products, like the Precise Path RG3 greens cutter, until GPSnavigation on robotic mowers is cheap enough, precise enough, and reliable enough to deliver consistent and safe operation for multi-acre grass-cutting machines.

The Bottom Line

  • Lawn and garden care is a massive and growing market, and lawn mowers constitute a substantial portion of it.
  • The robotic lawn-mowing market has both business-to-business and business-to-consumer components.
  • Navigation and obstacle avoidance remain challenges, but systems are improving.
  • Lack of customer acceptance, exacerbated by safety concerns, continues to dog the market.
  • Price and reliability are the primary selection criteria for traditional mowers.
  • Consumers are price sensitive, yet at this time robotic lawn mowers are considerably more expensive than traditional mowers.
  • A variety of robotic mowers, differing in operational approach and price, are available to the public.
  • Robotic lawn mowers are available from producers of traditional lawn-mowing systems as well as dedicated robotics companies.