Let the Robot do the Lawn

Enlarge Image Image Gallery The LawnBott Evolution can maintain an acre of lawn, divided into three separate zones. Oscar H. Will III

No longer just a futuristic dream, or an engineering class’s group project, robotic lawn mowers have evolved into sophisticated vegetarian pets that are dependable, largely self sufficient, and don’t leave any messes to clean up later. Imagine a quiet little shell-backed machine that wakes itself on schedule, emerges from its hutch, checks for rain or wet grass and when neither are present quietly goes about the endless seasonal chore of lawn maintenance. Already this sounds too good to be true, but that’s not all. That same little mower uses no oil or gasoline; it feeds on a diet of electricity carefully drawn from a high-tech, rechargeable battery pack. Unlike many pets though, the robotic mower heads home and feeds itself when it gets hungry.

Commercially available robotic mowers span the range from consumer-oriented models with appetites smaller than a quarter acre to large commercial units able to groom more than five acres of lawn all season. Larger golf-course sized robotic mowers are in testing, and virtually all models are regularly updated with new controlling software and better environmental sensors. Grit recently took a close-up look at Kyodo America’s Italian-built LawnBott Evolution, an autonomous mower that can maintain nearly an acre of lawn divided in up to three separate zones. The Evolution weighs a mere 22 pounds (thanks to its lithium-ion battery) in a package that is 22 inches long, 16.5 inches wide, and 10 inches high. Seems pretty small to be responsible for three-fourths of an acre, but this machine doesn’t work like a conventional mower or lawn service.

Not Your Father’s Pattern

Rather than mowing once a week, the Evolution works by cutting little and often on a semi-random path that avoids problems associated with conventional mower patterns. It begins each work cycle by starting off in a new direction looking for grass to mow. As the high-tech tool’s cutting blade spins, resistance data are fed back to the Evolution’s brain, which constantly monitors the current draw on the blade’s motor. If the cutter spins easily, then the relatively low amperage draw is interpreted as short or thin grass. Under these conditions, the Evolution’s software cuts the blade speed to conserve energy. When heavier growth is encountered, this LawnBott turns up the juice, and embarks on a spiral path to cleanly and completely trim the area. By integrating blade resistance over an entire mowing cycle, the Evolution keeps tabs on the lawn’s overall condition and adjusts its work schedule (within owner-input parameters) accordingly.

Once the Evolution has learned the yard, it becomes a lawn nibbler instead of mower. This characteristic makes the grass look perfectly manicured every day of the week, with the added benefit of producing clippings that are generally less than half an inch long. Short clippings readily break down to become fertilizer instead of hanging around as disease-promoting thatch. No more collecting, bagging or hauling clippings – even more time saved. If lawn scraps are an important part of your composting program, you will need to rethink, but then again, if you currently fertilize your lawn you will no longer need to. Nutrient and energy cycles aside, is this robotic mower stuff for real?