We have tested robotic lawn mowers and name Husqvarna Automower 315 as best in test. It runs very well, has a long cutting-time, is easy to set up and very good at problem solving. Best budget choice is McCulloch R600, which shares several advantages with 315 but has a lot less functions and works best on smaller lawns.
We carry out our tests ourselves and test all products as they are intended to be used in reality. The robotic lawn mower is what’s known as an “autonomous robot”, which means that it works independently. So it needs to be able to cope with a number of different situations and environments. Evaluating how it actually deals with these requires major product knowledge and is time-consuming.
To obtain test results that are as reliable as possible, we have tested the robotic lawn mowers for several months, on several different types of lawns and in different types of weather. This makes it possible to judge long-term effects and seasonal impact. For example, it’s often wet in the autumn but dry in high summer. The grass grows mostly at the start of the summer and the lawn is most brittle during the dryness of high summer and the autumn rains. Testing robotic lawnmowers under all these conditions also gives a better overall picture than simply testing them for a couple of weeks in the early summer – something that is common in other robotic lawn mower tests.
It’s also common in other tests to use only one grass area per model, on which the test body artificially tries to include all types of difficulty. However, our experience tells us that it’s extremely difficult to succeed with this. Primarily because it’s so difficult to predict all of the types of difficulties that different lawns present. So we think that the more types of lawn that a robotic lawn mower is tested on, the better.
In our assessment we have focused on the following characteristics:
Performance, effectiveness & reliability: How big an area of grass can the robotic lawn mower cope with? How intelligent is it? How effectively does it work in terms of time and cutting results? How long do you need to spend on the lawn? How good are the cutting results over the short and long term? How reliable is it? How often does it stop and report an error message, and in what situations? How good are the robotic lawn mower’s terrain-handling abilities? How does it cope with unevenness, roots, paths, steep slopes and loose surfaces? How does it cope with obstacles such as trees, bushes, flowerbeds, raised vegetable beds, sand pits, swings and trampolines? How well does it cut long, coarse and wet grass? How kind is it on brittle grass? How does the robotic lawn mower avoid wheel tracks along the perimeter wire? How does it cope with narrow passages, sharp corners, areas full of obstacles or secondary areas? How flexible can the cable laying be for it still to cope? Does it have an edge cutting function?
Ease of use: Is the installation quick and straightforward or slow and fiddly? Are there clear instructions, such as detailed illustrations or YouTube videos? How easy is the robotic lawn mower to programme? Is the menu system easy to navigate? How does the robotic lawn mower communicate with its owner? What type of information does it give? Can it be controlled with an app? How well designed is the app and what functionality does it have? How noisy is the robotic lawn mower? Can you be in the garden without being disturbed by the noise it produces? Can it work at night without disturbing the neighbours?
Design & construction quality: How well designed is the robotic lawn mower? How attractive is it? How well does the design aid the terrain-handling abilities? Do the wheels give good grip while simultaneously being kind to the lawn? How much stress and wear does the construction tolerate? How tough are the blades? How quietly do the blades work, and how much force is required to power them? Do the blades give a neat cut or do they tear the grass? How often do you have to replace the blades? How easy and how expensive is this? Does the robotic lawn mower easily get scratched or dirty? What guarantee does it have? Are there spare parts?
Functionality/safety: What settings are available? How much control does the user have of the cutting schedule? Does the robotic lawn mower use pivot blades or fixed blades? Does the signal in the perimeter wire interfere with other robotic lawnmowers? How safe is the robotic lawn mower? Can children or pets get at the blades? How much damage do the blades do, for example to forgotten toys? How effective is the theft protection? What happens if you forget the PIN code, or somebody enters the wrong PIN code?
We have pushed each robotic lawn mower to the limits of what it can cope with to see what types of situations and environments it can handle. Each robotic lawn mower has been given a score according to its value for money; in other words how good it is in each area in relation to its price tag. An expensive model thus has higher expectations than a cheaper one, and vice versa. We noted how often, where and why each robotic lawn mower stopped, and what consequences that had on the cutting result.
Robotic lawnmowers have existed for more than 20 years, but it’s only in recent years that they’ve really taken off in popularity. This is at least partially due to falling prices, but also because the range of models has grown and robotic lawn mowers generally have improved significantly. Another important factor is probably that many people buy their own robotic lawn mower after seeing that the neighbour's model actually does the job and produces a satisfactory cutting result. This means that robotic lawnmowers spread in clusters, with one area of housing having considerably more than the next. But the trend is clear. The robotisation of lawn mowing is unstoppable. The traditional push lawn mower is still far from extinct, but the robotic lawn mower represents a constantly increasing share of new sales.
It’s hardly surprising that not all robotic lawnmowers are as good, and factors such as performance, efficiency, reliability, functionality and safety vary more than you might think between different models. With a correctly executed installation, the best robotic lawn mowers can get by for several weeks without stoppages, while the worst can have difficulties even finding their way home to charge. The best lawn mowers require little adaptation in terms of cable laying and surface for reliable cutting, while the worst ones have strict requirements in terms of surface, gradient and the design of the area to be cut. The safest robotic lawn mowers are so well designed that it's almost impossible to injure yourself on them, while the worst can constitute a safety hazard for things like feet or inquisitive small fingers. Some models can even escape from their enclosure and play havoc with the neighbour's flowerbeds
Our tests show that more expensive robotic lawn mowers generally perform better than cheaper ones, but that’s not always the case. Nor is it certain that a robotic lawn mower with a good theoretical performance in terms of surface capacity and gradient will live up to this in practice. In other words, you shouldn’t get too caught up in the specifications about how many square metres a robotic lawn mower can cut in theory. What’s much more important is the robotic lawn mower’s reliability and how much perimeter wire is supported by the base station, as these factors are more decisive in determining the cutting area it can cope with. Another factor to take into account is the type of signal used by the robotic lawn mower’s perimeter wire. Some models actually interfere with other robotic lawnmowers, which isn’t exactly desirable for a good relationship with your neighbours.
In our test of robotic lawn mowers, we have tested the market’s foremost models to find out how well they perform. The best robotic lawnmowers perform really well, but you get what you pay for and a model that can cope with a moderately tough to difficult lawn costs about £1500. However, this should be viewed in relation to the most expensive models that cost upwards of £5000. But if you have a flat, uncomplicated and not too large lawn you can get by with a significantly simpler model for around £1000. However, there's a big difference between a budget and premium robotic lawn mower, and a budget model isn't always enough to get the job done.
Because both price and performance vary so significantly between different models, we have divided the test candidates into three different price classes and named the winner in each price class as follows:
Budget: up to £1100 Robotic lawn mowers in this price class should be able to cope with smaller, uncomplicated lawns with a uniform surface. Both problem-solving ability and terrain-handling abilities are normally quite limited.
Medium: approx. £1100-£2000 In this price class you should be able to expect that the robotic lawn mower will be able to cope with relatively tough lawns of around 1000 m². Both the problem-solving ability and terrain-handling abilities should be sufficiently good to deal with the majority of lawns. Unfortunately, many medium priced models can’t cope with this.
Premium: more than £2000 Models in this price class should be able to cope with large, complicated lawns with many obstacles, narrow passages and complex cable laying. They should ideally also be able to cope with steep gradients and troublesome surfaces. Unfortunately a large proportion of premium models fall down on several of these points.
AI stands for Artificial Intelligence. This is what gives robotic lawn mowers their problem-solving ability. Just like people, the better they are at solving a variety of problems, the more intelligent robotic lawn mowers are considered to be. Working out how to make a robotic mower more intelligent is an extremely expensive process that involves a great deal of trial and error. For this reason, robotic lawn mowers from companies that have been manufacturing them for a long time tend to have a better AI than newcomers, whose models often demonstrate "teething troubles" in terms of problem-solving ability. In practice, this is because some manufacturers have succeeded in creating more intelligent algorithms than others. An algorithm can be seen as a set of instructions that tell the robotic lawn mower what it should do in a range of different situations.
Probably the major reason to buy a robotic lawn mower is to save time and effort. So it's obvious that you want it to be user-friendly.
To begin with, installation should be simple and straightforward, so that you can easily start using your robotic lawn mower. Some models are easier to install than others, and this difference can be particularly clear if you're doing the entire installation yourself for the first time.
When the installation is complete, the most important aspects that must be user-friendly are the robotic lawn mower's computer and control panel. The interface and menu system should be so intuitive that it's easy to navigate through the different functions. If the control panel has too few buttons, programming becomes time-consuming, while too many buttons can be confusing if the layout isn't sufficiently clear.
Robotic lawn mowers are expensive and complicated products, so it's important they don't break down. The factory guarantee covers the initial period, but after that you have to pay for repairs and maintenance yourself. In general, a high build quality means a durable robotic lawn mower. To have a long lifetime, the robotic lawn mower should also be impact resistant and not sensitive to external influences. It should therefore be moisture-resistant; in a rainy and damp climate, moisture should be prevented from penetrating the many circuits that make up a robotic lawn mower. It should also be heat-resistant so that it doesn't overheat from being out in the blazing sun for days on end. The blades should also be robust so that they don't bend or break when they hit hard objects such as stones, roots or forgotten toys.
The design of the robotic lawn mower determines not only how attractive it is but also how reliable and durable it is – and how well it handles difficult terrain. Robotic lawn mower designers must constantly manage conflicts between aesthetics, performance, functionality, manufacturing costs and safety. For example, a bigger cutting width is almost always preferable from a purely technical perspective, as it makes the robotic lawn mower more stable and quicker at cutting the lawn. At the same time it's also more expensive to manufacture such a mower. A smaller safety buffer around the inside of the housing makes possible a wider cutting width but simultaneously increases the risks of accidents. In the same way, a big red "STOP" button is useful from a safety viewpoint, but from an aesthetic perspective it's nicer if it's a bit less visible. So in a well-designed robotic lawn mower, all of these factors are taken into account.
Reliability is perhaps the single most important characteristic of a robotic lawn mower. The whole idea of a robotic lawn mower – like all other types of robot – is for it to look after itself and to require as little work from its operator as possible. When the robotic lawn mower has been installed and programmed, it should therefore require minimal effort from its owner. An extremely reliable robotic lawn mower won't necessarily be able to cut the grass everywhere, but at the same time it should never get stuck anywhere either. But of course you also want it to be able to cut the more tricky parts of the garden. In practice, this means that no robotic lawn mower is completely reliable, and that they all sooner or later get helplessly stuck somewhere. However, for the most reliable robotic lawn mowers this happens very rarely, while the least reliable get stuck very often. The characteristics that are most important for reliability are the robotic lawn mower's terrain-handling abilities and its AI.
A robotic lawn mower's terrain-handling is the decisive aspect of its functionality. Partly because it determines where the robotic lawn mower will be able to cut the grass, and partly because it indirectly determines how often the robotic lawn mower will get stuck.
The most common obstacles that we identified in our robotic lawn mower test are:
Lumps and bumps: The simplest lawn for a robotic lawn mower to cut is completely flat. However, this is an ideal that the majority of lawns simply don't meet. Particularly in Sweden, where lawns are often allowed to retain a slightly more wild character. So it's common to encounter lumps and bumps – particularly small ones – which you don't necessarily think about before they cause problems; for example for your robotic lawn mower.
Gradients: Lawns often extend over inclined ground such as slopes, banks etc. Sometimes the gradient is minimal, sometimes it's severe. It's primarily major gradients that cause problems for robotic lawn mowers, even if the slope itself is short. Sloping ground is a challenge for robotic lawn mowers, and the majority of them can cope with a maximum 15° gradient. The best models can cope with 20-25°, which means that they are able to handle the majority of garden gradients.
Obstacles: Obstacles can be found in practically all gardens, and present the most common type of challenge for robotic lawn mowers. There are many common obstacles, which include trees, fences, walls, posts, compost heaps, pots, bushes, roots, paths, patios, flower beds, flagpoles, statues, sandpits, raised vegetable beds, log piles, swings and trampolines. The challenges created by obstacles vary significantly in type and level of difficulty. The most common obstacles are also among the most easily managed and involve hard, uniform objects that stick straight up out of the lawn, such as trees and fences. All robotic lawnmowers should handle these with ease. More difficult obstacles are things like bushes, trampolines and swings if they are attached to the ground with planks. The roots of bushes can trap robotic lawn mowers, while they can easily get stuck in trampoline legs or any planks used to attach swings.
Surface: There are a number of different surfaces that provide major challenges for robotic lawnmowers, such as roots, gravel, loose earth/sand, newly planted grass, leaves, pine cones and clay. These all create a loose and/or slippery surface which it is easy for the robotic lawn mower's small wheels to get stuck in. To handle difficult surfaces efficiently therefore requires sufficiently large wheels with sufficiently effective patterns. Of course the width of the wheels also affects the terrain-handling capacity, but with the right pattern and a machine that's not too heavy the wheels can be kept surprisingly narrow.
Challenging cutting surfaces: There are a number of common cutting surfaces that are particularly demanding for robotic lawn mowers.
Narrow passages/bottlenecks are challenging for a robotic lawn mower as it doesn't have eyes and so can't see in which direction the passage goes. This means that the lawn mower finds it difficult to "find the right way" and instead moves from side to side in the passage. Intelligent robotic lawn mowers have been programmed to avoid this type of situation and to quickly escape. A common trick that many robotic lawn mowers use to guide themselves through narrow passages is to follow the perimeter wire for a certain distance from the base station or to follow a guide cable.
Sharp corners are often a problem as they risk causing the robotic lawn mower to "go off track" and cross the perimeter wire. A safe lawn mower stops by itself when it realises that it has left its "enclosure", but on the other hand it will remain stationary until the owner reactivates it.
Corner areas with lots of obstacles can represent challenges as the lawn mower risks becoming "trapped" if it constantly collides with either the perimeter wire or the obstacles surrounding the corner. To avoid the robotic lawn mower wasting time in a corner therefore requires a sufficiently intelligent robot that can quickly work out an escape route.
Secondary areas are areas that are separate from the primary area but which must also be cut. For example, a secondary area could be the smaller lawn in front of a house with a big lawn (the primary area) in the back garden. Often the secondary and primary areas are connected by a narrow passage.
Robotic lawn mowers are not intended or designed to cope with long, coarse or wet grass. An overgrown lawn may therefore need to be cut with a conventional lawn mower before it becomes manageable for a robotic lawn mower. This applies particularly to small lawn mowers. Even if the lawn mower manages to force its way through the long grass, it often has to drive over the area several times in order to gradually cut the grass short. The lawn mower's wheels press the grass down each time it passes, which often results in the long grass gradually lying down rather than being cut. This particularly applies to robotic lawn mowers with pivoting blades, which are designed to give if they encounter too much resistance. Long and coarse grass is therefore one of the few areas where fixed blades are preferable to pivoting blades.
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