How Does A Robotic Lawnmower Work?

Last updated on October 23rd, 2023 at 08:52 pm

A robotic lawnmower is a very practical device, with which you no longer have to mow the lawn yourself. Of course, this has the advantage for you that you no longer have to do this work. The robot drives the lawn completely autonomously and helps you with the lawn care.

But how does the robotic lawnmower work, what preparations do you have to make and is the robotic lawnmower also suitable for your garden?

The principle of the robotic mower

The robotic mower is largely equivalent to a normal lawn mower. On the underside of the robotic lawnmower are sharp blades with which the grass is cut. The main attraction here is that the device is completely autonomous and takes care of the lawn.

To ensure the autonomy of the robotic mower, it works according to the mulching system. This means that the cut grass is not collected in a collection container, but is shredded to such an extent that it can be used as fertilizer for the lawn. The mulch here is not waste, but has positive properties for the maintenance of the lawn.

In order for the robot to drive in your garden, it draws its energy from a rechargeable battery. Driving with a cable is too cumbersome and would cause the robot to get stuck in difficult places. To get around this problem, all robotic lawnmowers use a battery.

You don’t have to worry about the robot getting stuck on the track. If the battery runs low, the smart device detects the condition and independently returns to the charging station.

But how exactly does the robotic lawnmower work and how helpful is it in garden maintenance?

How does the robotic lawnmower orient itself

One of the most important features of the robotic lawnmower is how it orients itself in the garden. After all, we want the lawn to be free of imperfections and deliver as good a job as humans do.

Humans have a much easier time mowing the lawn. We can perceive with our eyes where the garden area begins and where it ends.

The robot is not only much smaller, but it also cannot independently decide where the boundary of the lawn is. For this reason, most robotic mowers work with a boundary wire. This is attached to the ends of the green area and signals the robot that this is the end and it does not need to continue.

Alternatively, there are either robotic mowers with GPS or robotic mowers without a boundary wire that use a variety of sensors. However, the latter version is only suitable for gardens that have a clearly marked out lawn area. Paving stones can serve as a boundary here, indicating to the robot that the end of the green area has been reached here.

The boundary of the robotic lawnmower

However, most robots use a boundary wire for their travel. This ensures a high level of safety and there is no risk that the robot will drive somewhere where it does not really belong.

On the other hand, there is of course the annoying laying of the boundary wire. After all, the overall picture should be preserved and not disturbed.

The boundary wire is a small wire, which is attached either directly under the turf, or directly on the lawn. The wire creates a magnetic field that signals the boundary to the robot.

The laying of the wire can be done either by yourself or by a professional. Since the wire will grow over after a short time, there should be no visual interference. Nevertheless, the cost of installing a robotic mower with boundary wire is relatively high. However, the higher safety and the relatively low costs speak for this type of boundary.

What sensors does the robot use

Regardless of whether a boundary wire is used or not. The robotic mower needs sensors so that it can orient itself in the environment. Without these sensors, it would constantly bump into any objects and would have plenty of problems. But what sensors does the robot have?

• Bump sensors help the little device to detect when obstacles are in the way. If a tree suddenly piles up, then the impact sensors detect this obstacle and change the direction of movement.
• Tilt sensors ensure that the shears do not become a danger to humans or animals. If the robot tilts and the blades would be exposed, then the robot stops its work and stops the blades automatically.
• Distance sensors are responsible for not only detecting obstacles, but also measuring the distance. This prevents the robot from attacking flowerbeds or other important areas with its blades.
• Rain sensors measure the humidity of the environment. Most robotic mowers are not designed for driving in the humid environment. Measure that it begins to rain, then they return to the charging station.
• Lawn sensors tell the unit what surface it is on. Ideally, the robot should only drive on and cut grass. If it notices that it is on another surface, then it looks for an area that corresponds to the lawn.

How they cut the lawn

With robots, just like with humans, there are different ways and options to mow the lawn. Some are rather chaotic and mow on a whim and after a while the entire area is covered, while other garden enthusiasts proceed in a very orderly manner and make their tracks.

The robotic mowers can follow a free movement pattern. In this case, they drive off the lawn relatively chaotically. The advantage is that no strips are left standing and the entire lawn area is worked relatively evenly. However, there is a risk here that smaller areas could be left out.

The other approach involves the robot working the lawn in orderly paths. In this way, no spots are left out, but it is clearly visible in the lawn pattern that such a path has been cut. If this does not bother you, then driving in lanes is preferable.

What lawns can be covered

Not every lawn is the same size, and with modern technology, the battery is one of the limiting factors of the robot. What lawn areas can be reliably covered by the robot or are there even limitations on the maximum size?

Generally speaking, most modern robotic mowers are suitable for just about any lawn area. Depending on the size, there are different segments.

These are divided into small, medium and large lawns.

Robots designed for small lawns can handle a lawn area of 300 to 500m².

A medium lawn ranges from about 500 to 1,000m².

Anything beyond 1,000m² is considered a large lawn area. This requires special robots that adapt to these requirements. Professional applications are often required here, which is why robotic mowers are specialized for sports fields, or other cases.

However, it is not only the coarse lawn area that is decisive. This says nothing about how much energy the robot must ultimately expend in the processing. In addition to the pure area, the condition of the soil and the garden is also important.

If there are many slopes, if the ground requires more power, or if the grass is particularly difficult to cut, then more energy is required from the robotic mower. Accordingly, its range will be limited.

How the robot is controlled

A modern robotic mower has numerous setting options. Installation and setup are not always easy, and depending on the model, the user manual should be studied carefully.

The length of the blades and thus the cutting depth can either be adjusted via a simple controller, which is located on the housing, or via an app.

Many modern robotic lawnmowers can nowadays be controlled via app and all settings can be made within the app. Therefore, either an iOS or Android mobile device should be available that can access the manufacturer’s app.

If a particularly high-quality result is to be aimed for, then it is recommended that the cutting depth is gradually reduced. This allows the robotic lawnmower to work its way up to the desired length step by step.

Are there any safety risks of the robot mower?

With all modern devices that operate autonomously, we inevitably ask ourselves whether they are also safe for the environment and can not cause any harm. Whether it is autonomous vehicles or small robotic mowers, the concern is definitely justified, as it is a device with sharp rotating blades.

However, your worry can be calmed, because there is no real danger from these automatic lawn mowers. This is because the tilt sensor allows the little robot to find out if it is being lifted, and if it tilts too much, the blades will automatically stop.

This not only protects adults or small children nearby, but also smaller animals that might be in the robot’s path.

To prevent small children from being able to start the robot first, most devices have a child lock. This allows the robot to work in the garden in peace, and you can rest assured that safety is guaranteed at all times.

One risk the robot is not protected from, however, is theft from the outside. If your garden is designed relatively open, then the robotic mower can be stolen while mowing.

Although the modern devices have anti-theft protection, but this can not prevent the device is gone first.

What is the cost of operation
The purchase of the robotic mower is associated with the desire to spend less time mowing the lawn. This goal is definitely achieved, because the robot works completely autonomously and does the work by itself.

But how high is the maintenance effort of a robotic lawnmower?

Compared to a conventional lawn mower, the maintenance required for a robotic lawnmower is much lower. The cut grass is distributed back onto the lawn, where it serves as fertilizer.

For safety, the device should be cleaned of grass residues at weekly intervals. This includes cleaning the charging contacts and the blades.

The blades need to be replaced every few months or when you realize that the lawn is no longer cleanly processed.

The battery life is a couple of years. Over time, the capacity of the battery will decrease, making it necessary to replace it. The cost of the battery is still manageable at about 50 to 100 euros, and since the change only needs to be done every few years, this is manageable.

Are the robotic lawnmowers loud?

The normal lawn mower is not exactly conducive to neighborly relations due to its high volume. Therefore, lawn mowing is only allowed at certain times.

However, the robotic mower is not subject to these restrictions. It performs its work steadily and very quietly. The volume is a manageable 50 to 75 dB. This means that you can read a book in peace, or relax in the garden while the robotic mower is doing its work.

How to charge the robotic lawnmower

The robotic mower gets its energy from the battery. As expected, the battery must be charged to prevent the robot from lying on the track while working. For this reason, robots can independently detect when the battery level is low and find their way back to the charging station.

This happens with robotic mowers that work with a boundary wire via the so-called guide wire. This is also laid in the lawn, but unlike the boundary wire, a signal is not constantly emitted from this wire.

It only becomes active when the battery level is low and the robot is looking for the way to the charging station.

Other ways to find the charging station is to use GPS to locate the place. However, this type of robots with built-in GPS are still relatively rare and infrequent.