A boundary wire may seem like an inconvenience or something that is the last thing you need to think about, but we’ll soon see that the vast majority of robotic mowers on the market count on this wire for their navigation capabilities.
The perimeter wire is essentially a large antenna giving a constant signal letting the robot mower know where it can and cannot mow.
Installation of the wire can be tedious and complicated, however, robotic mowers that are wire-free can be quite pricey and out of the price range for most consumers.
This article will help you understand the significance of the perimeter wire for robotic mowers as well as some of the alternative technologies that are used for effective navigation of autonomous mowers.
For now, a boundary wire is essentially a default feature of robot mowers.
Just like a young child, your robotic mower needs a firm edge to work optimally. With that established boundary, they can mow your lawn freely.
This wire is used to define the boundary of the grassed area to be cut and can work with any size or shape of lawn. This may not be what most people expect when I mention “wire”.
How does boundary wire work with your robotic mower?
While robotic mowers are intelligent machines, they aren’t quite intelligent enough to navigate autonomously. These mowers will drive and mow in a straight line until they hit the boundary wire which make them change direction.
A conventional robotic mower mows and turns at the boundary until it has mowed the entire lawn.
It really is that simple.
The boundary wire is connected to the mowers charging station and sends a continuous signal
The wire can be described as a boundary wire, which attaches to the charging station of your robotic mower, the wire creates a continuous loop around the perimeter of your lawn.
The center of the wire is copper and conducts a unique UHF signal specific to the mower through the wire in all directions to the robot, allowing it to identify its boundary at all times.
Manufacturers make robotic mowers with boundary wire because they are effective
As long as the boundary wire is not covered or broken, it is a strong, reliable and effective system.
This technology is repeatable and reliable, and it means that the mower cannot mow areas such as flowerbeds or gravel paths by accident.
As this technology gains acceptance, boundary wire robotic mowers have become cheaper. This means that almost all robot mower models will have this type of technology.
But boundary wire adds complexity to setting up robotic lawnmowers
It’s understandable why you would like to know if all robotic lawn mowers require a boundary wire, since the requirement for a boundary wire will imply having to install it, and that can be very frustrating.
The boundary wire must be installed accurately. If the installation process is performed incorrectly, the causes will be that the mower doesn’t mow well or possibly doesn’t work at all.
With major lawns or complicated ones, it is easy enough to get the installation wrong. Plus, you can mess up securing the boundary wire with pegs, sequence, under rocks, or even if you had to bury it.
If that wasn’t enough, once the wire is broken anywhere along its line, you have stopped the robotic mower from working.
All that is needed is a creature chewing on the wire, yard work, or a bit of intense play in the backyard. Once you have a break, you will have to find and fix the break with a connector, or you will have to replace the entire wire.
Alternatives to boundary wire do exist but are not widely available
The technology for robotic mowers to navigate autonomously is actively in development, with one or two robotic mowers having already become available which do not use wire.
Alternative technologies are still very expensive and do not provide the consistent functionality needed to ensure that a robotic mower only mows grass.
For the time being, the manufacturers are mainly leaning on what they know and just add new enhancements and functionality to existing boundary wire robotic mowers.
Here are some examples of alternatives to a boundary wire
New navigation technologies for robotic mowers are generally in the early stages of development.
Some of the new technologies are adapted from applications in other sectors such as agriculture where navigation technology are commonly used to sow or harvest electronically.
Most of the other technologies are completely new, and much work needs to be done before these technologies will be commonly accepted. Here are the technologies to watch:
Real-time kinematic GPS corrects errors in GPS so a mower can mow accurately
This is an enhanced type of GPS that offers centimeter accuracy as opposed to ordinary GPS which can be displaced by meters, a tolerance that would not work for the robotic lawnmower.
Real-time Kinematic GPS (or RTK GPS) is based on the same navigation techniques used by combine-harvesters and other agricultural equipment, so your lawn gets mowed correctly.
RTK GPS uses a base-station that allows the mower to determine its position and not use a boundary wire. The mower then uses onboard GPS transceiver to navigate according to the outline of the lawn that has been mapped.
Beacons help a mower orient itself without a boundary wire
Certain manufacturers are testing a system of staked beacons as an alternate way of delivering a boundary signal.
Surveyors and civil engineers utilize these radio beacons due to their high accuracy. User to assist and correct the GPS-guided mowers can require location beacons too.
An onboard camera could solve wire-free robotic mowing
There are now manufacturer prototypes on the market of robotic mowers that navigate visually, using an onboard video camera and artificial intelligence to “see” grass and other garden features.
Visual navigation, like self-driving cars, is a rapidly developing area of robotics, and involves complicated and costly software.
While we are still some years away from commercializing this type of robot mower, there are encouraging prototypes.
Stay tuned!
Rounding up
While the boundary wire takes some mystery out of how autonomous mowers work, a boundary wire is able to guarantee that you will receive a perfectly cut lawn, without having to cut it yourself.
If you feel that installing or repositioning a boundary wire is too difficult, you could always have a professional install your boundary wire and properly set up your mower!
Until a different technology presents itself, it seems this trusty spool of wire is here to stay!