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Systematic mowing has altered robotics, turning 2023 into a technological tipping point
Autonomous mowing technology in 2023 put it 10 years ahead of 2022
May 21, 2024 By Mike Jiggens
Robotic mowing technology is being embraced by all sectors of the turfgrass industry for its simplicity, its ability to address labour shortages and for its precision cutting. What initially began as wire-bound, random cutting technology in landscaping has progressed to systematic mowing that has since been adopted by sports turf and golf course maintenance professionals and sod growers.
Last year was regarded as a tipping point in robotic mowing technology.
“(The year) 2023 might as well have been 10 years ahead of 2022 because everything changed in one year where it made mass adoption of robotic autonomous technology completely possible,” Dr. Scott McElroy, a professor of weed and turf science at Auburn University in Alabama, told attendees at February’s Ontario Turfgrass Symposium in Guelph. “It all happened because of the ability of the robots to position themselves in space. Positioning themselves in space allows them to mow and function systematically.”
This means robotic mowers can move directionally, choose a direction and function in that direction, and mow in straight lines. Previous generations of robotic mowers were limited to random movements within wired perimeters, making mowing inefficient.
“You could only get out of them about 30 to 40 per cent of the total capacity that you can get out of a systematic mower,” McElroy said.
The advanced technology has allowed virtually every form of mowing possible, but there’s still some growth to be realized, he said.
Golf courses, for example, have adopted robotic mowing on fairways and roughs, but still mow greens in the traditional manner due to the need for close cutting that only reel mowers can achieve.
McElroy said there are many turf professionals who are reluctant to adopt the new technology, claiming it’s “not there yet,” and don’t wish to be a guinea pig.
“You’re not a guinea pig at this point in time,” he assured.
Europe leading in robotic mowing
North America is well behind Europe in the deployment of robotic mowers with about 80,000 mowers at work compared to 1.3 million. Most of the robotic mowers currently deployed in Europe are for residential use.
“There’s growth, development and technology that’s going to occur, but the base technology that everything’s going to run on is implemented today.”
McElroy said the algorithms and software that drive robotic mowing will become better and more efficient in the years to come, but the current hardware is likely where it’s going to be for the next decade.
Several fully autonomous mowing systems use micro rotary blades – which are like razor blades – to mow, but the mowing frequency is almost double, he said, adding they don’t have suction and won’t mulch. They’ll knock off dew but are essentially just mowers. If there’s ample grass to be cut, the mowers will churn through it, but it will require more time.
Robotic mowing technology’s software apps allow operators to learn the pros and cons and likes and dislikes of the technology.
“You can see the interface of the mower and world around it to maximize where it likes to work and when it likes to work.”
McElroy said the thinking robot is trying to accomplish two things – it’s trying to position itself in space as well as sensing what’s around it. It positions itself through GPS (global positioning system) and RTK (real time kinematics), the latter of which is the physics of positioning things in space.
“It’s what put man on the moon and what keeps satellites in orbit.”
With real time kinematics, GPS and an RTK base station – with which the robot communicates – are required. McElroy said it’s simply a tower that’s set up which positions itself and knows precisely where it’s at and isn’t just dependent on satellite. Sensing is achieved by ultrasonic sensors and LiDAR computer vision which is the same technology used in the manufacturing of self-driving automobiles.
“They need to know where they’re at and what’s around them.”
Autonomous mowers are used to cut roughs and fairways on golf courses, but aren’t adapted for greens mowing.
Photo: © Husqvarna
Lines of communication
The robot is communicating with satellites, but it may be hampered by trees or other obstacles. Robots work off a beacon (or reference station or RTK station). Some companies’ autonomous mowers work from different types of beacons. Low or short-range beacons will stretch 200 to 300 yards and will require daisy chaining to create a mesh network. Longer-range beacons stretch about five miles or 10 kilometres.
Other companies have adopted network RTK systems, McElroy said, for which they buy a service like that used in cell phone services.
In the works are add-on features that allow robotic mowers to adequately function beneath trees, next to buildings, underneath power lines and around other overhead obstacles. Buildings more than two storeys tall and large canopied trees can knock out signal with today’s technology, but LiDAR allows units to better sense what’s around them, allowing them to function when they lose signal.
LiDAR computer vision adds a new layer to robotics in terms of being able to function around signal-obstructing impediments such as trees, McElroy said.
He said autonomous mowers are essentially computers that cut grass. Units don’t require repair as much as they’ll need replacement of key parts such as motherboards, sensor boards and small motors that drive the wheels and cutting implements.
“The ability to diagnose what part you need to replace is critical.”
Robotic mowers that don’t require touching to be deployed or have traditional cutting implements are regarded as semi-autonomous. McElroy said semi-autonomous systems work best in sod farm applications.
Wondering if autonomous mowing will take away people’s jobs, he said, “perhaps not, but you’re not going to hire people once you can do certain things.”
Ultrasonic sensors are the key component, McElroy said, adding they’re cheap and reliable and function in all kinds of weather.
Fully autonomous equipment is comparatively slower and doesn’t function at speeds greater than 2.2 miles per hour, he said.
The key things to consider in autonomous mowing, McElroy said, are the amount of control operators have over the mower, the planning and scheduling, problem solving and troubleshooting.
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