Robotic lawnmowers could cut a huge swath in air pollution

Like it or not, mowing the lawn has become an inescapable American chore for many Americans.

Whether you’re the neighborhood kid striking out in entrepreneurial style or a newly minted homeowner, odds are you’ve either pushed or ridden a gas-powered mower in your time. But this often sweaty and tedious task isn’t just a time-suck on your afternoons. It’s also has a serious impact on the planet in the form of CO2 and NO emissions and spilled gasoline.

But there’s a larger than expected environmental impact — up to five percent of the nation’s total air pollution, and that’s just from the engines. An hour of lawnmowing may have the same emissions as a 100-mile road trip. And that doesn’t even consider collateral like spilled gas and leaking oil.

Instead of ripping up lawns across the country, roboticists have another solution that could save emissions as well as time: Roomba-like robotic lawnmowers.

What is a robot lawnmower?

Similar to a Roomba or other smart vacuum, robot lawnmowers are small — yet rugged — outdoor bots designed to cut your grass for you with only the push of the button. While this technology has already been around for a decade, it has yet to really catch on in the United States as it has in places like Europe.

“Americans like a big yard.”

Stephan Roth is the founder and principal engineer at Sensible Machines, a commercial robotic lawn care company. He tells Inverse that this might be due in part to the bigger-is-better complex that Americans tend to have with their lawns.

“Robotic lawnmowers work best on smaller yards,” says Roth. “Americans like a big yard.”

WHY DO HUMANS WANT THIS?

On the one hand, robots in their simplest form are tools for humans to get more done with less physical effort. But robot lawnmowers present unique opportunities to be environmentally friendly options for landscaping thanks to the use of lithium-ion batteries (the same kind of battery that powers your laptop, cellphone, or Tesla) instead of chugging liters of gasoline every time you mow.

“If the mower runs over something it's not supposed to, that thing will probably be damaged and send shrapnel flying”

WHAT ARE THE ETHICAL IMPLICATIONS?

Roth suggests that perpetuating lawnmowing is an environmentally (if not also morally) fraught endeavor, to begin with, referring to the massive amounts of water and other resources that go into caring for our lawns every year, especially in drought-prone parts of the country like California.

“I wouldn't call mowing a yard an environmentally friendly activity,” says Roth.

But while robot lawnmowers aren’t a carbon-neutral activity by any means, they can offer a greener alternative for those who won’t pull up their Kentucky blue.

Another possible concern of handing over your lawn work to a robot is that it doesn’t yet have the keen eyes for identifying living obstacles (like a bird's nest or hedgehog) before it’s too late. In Europe, where hedgehogs and robotic lawnmowers are both more common, this has been a persistent issue.

HOW DOES IT ACTUALLY WORK?

Roth explains that robotic lawnmowers designed for home lawns (as opposed to larger, commercial lots) aren’t quite as similar to your indoor robotic vacuum as you might think.

“For this kind of machine, you can't take a Roomba's approach and blindly bounce around the area,” says Roth. “If the mower runs over something it's not supposed to, that thing will probably be damaged and send shrapnel flying.”

“You need to sense the environment to determine where it is safe to go. Also, to maintain a nice appearance to the turf, you need to mow in nice, neat rows. This requires the robot to localize and orient itself fairly accurately over a large area.”

In a nutshell, robotic lawnmowers work by using a mix of sensing and planning algorithms.

Chen-Kang Huang is a professor of biomechatronics engineering at National Taiwan University who has contributed to papers on intelligent lawnmower design. He tells Inverse that these sensing approaches are still being refined but that the newest designs for robotic lawnmowers use a form of computer vision (the same kind of intelligent “seeing” that keeps your self-driving car from, hopefully, hitting pedestrians) and path planning which prescribes where the lawnmower should go to most efficiently cut the entire lawn.

Huang also says that ultrasonic sensors and cameras can be used to detect obstacles before the mowers hit them.

But while these lawnmowers may be smarter than your gasoline guzzler, Roth says they’re still far from perfect.

“The current home robotic lawnmowers have limited sensing and planning,” says Roth. “This is really due to cost. A larger robotic lawnmower would need to have sensing more on a par with an automated car.”

Which robotic lawnmower is the best?

Nuts and bolts aside, what is the best robotic lawnmower on the market? According to PC Mag, there are a number of good options on the market for summer 2021.

Worx Landroid M 20V Cordless Robotic Lawn Mower (WR140)

For just shy of $1,000 this lawnmower is equipped with both Wi-Fi and GPS and can be controlled via your smartphone. For this reason, PC Mag says it's their top pick for best overall value.

Husqvarna Automower 435X AWD

For a little more heft, the magazine recommends this monstrous Husqvarna model (a veteran of the robotic lawn care game) that they write is especially good at daringly climbing up and down any hills your yard might have. The price point is equally steep at $4,299.

WHEN WILL ROBOTIC LAWNMOWERS TAKE HOLD IN AMERICA?

It’s hard to say exactly when these robotic lawnmowers will begin picking up pace across the pond in America, but if the continued delay of Roomba-manufacturer iRobot’s robot mower Terra is any indication, the saturation of the American market might still be a while away. (Representatives of iRobot tell Inverse Terra “will remain on hold for the foreseeable future.”)

Roth suggests that the potentially sloppy work of a robotic mower may also be a sticking point for adoption.

“I think [robot mowers] would mostly be for someone who isn't too concerned with the appearance of their lawn, but just wants the lawn mowed.”

WILL ROBOTIC LAWNMOWERS SAVE THE WORLD?

The EPA estimates gas lawnmower emissions account for as much as five percent of the nation’s total air pollution and that homeowners spill up to 17 million gallons of gasoline every year simply refueling their machines.

The EPA estimates 54 million Americans mow their lawns on a weekly basis, producing close to 97 million tons of emissions every year. Robotic lawnmowers won’t necessarily eradicate this problem, but they could potentially play an important role in weaning Americans off their gas-powered mowers — if only they were smart enough to mow in a straight line.