Mapping for robotic lawn mowers is the next evolution of innovation in these tools.
So, if you’re getting fed up hunting for a break in your mower’s boundary wire, you will want to learn more about the new technology that is enabling robotic mowers to cut grass without the need for a boundary wire.
In this short article – I will cover what mapping for robotic mowers is, how it works and its fantastic advantages for homeowners, including the ability to create stripes on your lawn.
Mapping is simply a method of outlining the area to be mowed by a robot
Instead of a finite perimeter wire, modern mowers can utilize new mapping technology to learn the shape of the lawn and optimize their mowing path for efficiency and order.
This is a game-changer because the makers have always preferred using a perimeter wire, as it is more definitive.
Every mapping technology assessed to date, including GPS guided automated mowing by various manufacturers, has demonstrated mapping errors that resulted in, at best, unmowed swaths of lawn or, at worst, over-mowed swaths.
Perimeter wire provides a clear boundary for robot mowers
The perimeter wire that was installed around the border of the lawn sends a signal that the robot mower can use to orient itself.
This known methodology creates a localized electromagnetic ‘map’ or outline of the lawn, and within this defined area, the robotic mower operates and cuts the grass in a sporadic ‘zig-zag’ pattern.
This is one reason why robotic mowers cannot cut stripes into the lawn
The mower never cuts in straight lines.
Under algorithmic control, the robotic mower mows in random directions making use of the wire as a boundary and mowing the entire lawn eventually.
Relying on the boundary means that the mower may miss edges and narrow areas because of poorly installed perimeter wire.
Satellite-guided robotic mowing using GPS is just not accurate enough
Who wouldn’t want a GPS-based robot mower when GPS can help you get your car to the right destination?
Although many have thought about using GPS for a robot mower; the accuracy of GPS greatly limits its usability when you move into relatively small areas such as a lawn.
A GPS signal relies on a broadcast from satellites which requires a good view of the open sky.
The signal is also adversely affected by the ionosphere and terrestrial obstructions which can significantly weaken the signal, leading to inaccurate navigation of the mower in the yard.
Furthermore, when operating with a uncorrected basic GPS signal, the accuracy is typically within a range of about 2-10 meters.
Keep in mind, that means the bot can totally miss your lawn and mow your flower bed or even end up in your pond.
Novel mapping methods are being developed for wire-free navigation
The majority of wire-free mapping techniques used for robotic mowers are designed to increase the precision of GPS or the utilization of signalling beacons that allow the mower to differentiate where the lawn is by the shape of the lawn rather than a continual boundary marker.
RTK GPS
An example of this technology is Real-Time Kinematic GPS, or RTK GPS, which is a type of assisted GPS often used in agriculture and surveying.
RKT GPS typically has a reference beacon or base station with a known accurate location that the mowers would use to establish a lawn mapping based on GPS.
Using this reference, the mowers will then orient themselves such that they can mow wirelessly to an accuracy of 1 or 2 centimetres.
Boundary Beacons
This technique for mapping an area to mow with a robotic mower uses multiple location beacons to represent the area being mowed as reference points.
These reference points can be used to orientate the mower to a map image of the lawn stored in the robotic mower with actual geographic coordinates from the reference points.
Smart Mapping
The process of smart mapping represents perhaps one of the most cutting-edge technologies for mapping a lawn, and allows the bot to mimic the systematic back and forth pattern of mowing that a human would have.
A Massachusetts based robotics company, called iRobot, has developed a mowing bot called Terra that is capable of learning the environment and mapping the lawn on its own.
The bot is unique in that it is able to remember where it is in the yard, using wireless beacons to orient itself.
Rounding Up
Mapping the lawn is vital to your robotic mower’s ability to function.
Once the new technologies, which do not require the perimeter wire, can demonstrate their accuracy, widespread acceptance will likely occur.
In the meantime, the perimeter wire is a proven, reliable method of mapping and navigating your robot mower.