Dossier How to choose the best robot vacuum cleaner?

Edit 05/06/2020 : beware, our article was published in November 2019 and things have already changed a lot since then, the best robot vacuum cleaner of the time is no longer, obviously. Nevertheless, you will be able to get these models at much better prices!

We have presented, in recent months, many robot vacuum tests. Of Deebot 502 au Roborock S6, Through the Cecotec Conga 3690 or the Deebot Ozmo 920 from Ecovacs, there is something for all budgets. If price is obviously a factor of performance, especially when it comes to navigation, there are some excellent entry-level devices such as the Proscenic 800T, while some high-end devices are rather disappointing like iRobot's Roomba. Before presenting the best robot vacuum cleaners on the market, we found it interesting to take a close look at the different criteria to be taken into account when purchasing. These are the criteria that we pay particular attention to during our robot vacuum tests and which allow us to compare, somehow, the many models available on the market.

Design: indulge yourself!

Let's start this file by tackling the most divisive subject: design! Certainly, all tastes and colors are in nature, but keep in mind that the robot vacuum cleaner quickly becomes a member of the family. Less discreet than a pregnant Amazon Echo, you will see it just as often and probably keep it for a few years. Without going so far as to expose it, it is therefore important to choose a device with a neat design. Whether it is white, gray or black, the important thing is above all that you like a minimum. And, given the price of these devices, only one watchword: indulge yourself!

Editor's choice:

This year, our favorite goes to Deebot Ozmo 920. Winner of a 2019 RedDot Design Award, a coveted international prize that rewards product and communication designs, the Ecovacs Robotics robot did not steal its prize. For lovers of white, you can turn to theOzmo 900 of the same brand or the now famous Roborock S6 et S5 Max (the S4 only exists in black for the time being) which generally offer a white livery.

Robot vacuum cleaner test - © Les Alexiens

Simple vacuum cleaner or 2 in 1 robot: make your choice!

This is one of the first criteria to take into account: do you only want to delegate vacuuming or also mop hard floors? In other words, are you looking for the best robot vacuum or the best robot vacuum and mop?

If this choice is up to you, do not imagine that a vacuum cleaning robot is less efficient in vacuuming than a vacuum-only robot. Some brands, which strangely do not offer 2 in 1, sometimes let it be understood… But it is false! Indeed, the best robots to date offer both features. The best vacuum cleaners are therefore also scrubbers.

However, keep in mind thatno 2-in-1 robot excels in washing floors. On a vitrified parquet, the result is generally rather satisfactory, but it is sometimes more approximate on a kitchen tile with little fattening. In fact, we have not yet found THE robot capable of making us definitely put our old mops in the closet. This is also one of the major areas for improvement in this market, brands are well aware of it, and some promising innovations are emerging.

In summary, if a robot vacuum cleaner and mop won't spare you a lot of elbow grease from time to time, the possibility of mopping the mop is still a big plus that we advise you to include in your criteria. 'purchase. If you really don't have any use for this feature, you can save a few dollars by switching to a simple vacuum cleaner, but remember that you don't have to use the washing feature ... 

Editor's choice:

Who can do the most, can do the least! We therefore advise you to opt for a 2 in 1 robot. Three high-end robots caught our attention from this point of view: the Deebot Ozmo 920 again, the Roborock S5 Max of course and the surprising Cecotect Conga 3690 Absolute which offers a rather efficient back-and-forth washing method. At the entry level, you can also turn to the Proscenic 800T / 820T which does as well on this point as the more upscale ones. Like what…

Noise: comfort or efficiency?

In the family of household appliances, the vacuum cleaner is one of the noisiest. Like sleds or brooms, the robot is no exception to the rule because of a motor generating a vacuum. If we can obviously link suction power and sound volume, the most powerful are not, however, the most deafening, the best brands working particularly on the sound volume of their devices.

So, once again, it is the top of the range that stands out. A Deebot Ozmo 920 displays in 54 dB (A) in silent mode and 69 dB (A) in max mode, which is very little. a Roborock S6 between 57 dB (A) for night mode and 72 dB (A) for max mode, which is still quite reasonable. Indeed, some devices can exceed 80 dB (A), which starts to be really annoying when you are present at home.

We therefore advise you to opt for devices offering several suction modes, and in particular a silencer that you can use in the evening for example, when you watch television or when the children are in bed. You can consider that a robot is rather quiet below 60 dB (A), extremely below 55 dB (A). The decibels being the power ratio between the sound pressure and a reference value which corresponds to an imperceptible sound, note that an increase of 1 dB (A) is immediately audible.

Editor's choice:

Our choice is on Ecovacs Deebot Ozmo 920 and Ozmo 950 which are, by far, the quietest, even if the Roborock S6 does not demerit, far from it. At the entry level, the Proscenic 820T also displays satisfactory levels.

In stock
15 new from € 377,06
Refurbished from 189
November 28, 2021 2 h 52 min
Amazon. Fr

Suction power and air flow: two different concepts

Many brands like to display the power in Pascal of their engine. Why? Because we can quickly put lots of zeros that create a “Wow! ". Unfortunately, this does not necessarily predict the actual performance of a robot and it is better to be interested in its air flow. Be careful, the power in Pascal is often a mirror to the larks!

Be careful, the power in Pascal is often a mirror to the larks!

So the brand new Xiaomi Mijia P 2-in-1 (STYJ02YM) only sucks 15 L / s with 2100 Pa of power, while a Roborock S4 aspirates 19 L / s (liters per second) with 2000 Pa. Even more significant example, the Deebot Ozmo 920 engulfs 24 L / s while it is equipped "only" with a 1500 Pa motor. The least powerful motor of the three offers in the end the better air flow to Deebot Ozmo 920 and therefore the best suction on the robot vacuum cleaner market! But how the hell is that possible?

It is very simple, it simply comes from the internal design of the robot. It is enough to lift their respective covers to realize it. the Xiaomi Mijia has a pretty low-end design, while the Roborock is equipped with much more qualitative components and in particular a silicone seal bordering the suction mouth on both sides which fits with its dust container. Silicone is more expensive, but it is more airtight and therefore effective.

Roborock S4 (left) and Xiaomi Mijia P 2-in-1 (right) suction ports

As for the Ecovacs robot, in addition to a much higher quality of assembly, it offers an absolutely unique floating brush on the market which drops as close to the ground as possible and literally slips onto the carpets. The result is final, the Deebot Ozmo 920 therefore aspires 24 L / s against 20 L / s for its ancestor the Deebot Ozmo 900 yet equipped with the same engine, proof that the depression created by the engine is not everything ...

In conclusion, if the value displayed in Pascal (Pa) does give an idea of ​​the depression created by the engine, and therefore of its pure power, it is not sufficient on its own. Indeed, the most important concept in terms of suction is that of the air flow which corresponds to the volume of air actually sucked by the robot. We are here on a notion of real efficiency rather than theoretical power. Obviously, it is not in the interest of many manufacturers to bring up this point and most only mention the vacuum power measured in Pa by evading the inspired air flow. But, thanks to the Alexiens, you now know how to make a difference!

Editor's choice:

Our choice, without any doubt, is on Ecovacs Deebot Ozmo 920 and Ozmo 950 which are, by far, the most efficient to date in terms of suction with up to 27 L / s, putting all of their competition under pressure.

In stock
15 new from € 377,06
Refurbished from 189
November 28, 2021 2 h 52 min
Amazon. Fr

Remote control and control application: significant differences

Remote control or not?

This may be a detail for you, but for some it means a lot: the ease of use. If, for technophiles, it is natural to unsheathe his smartphone and launch an application, this is not the case for everyone, far from it! Some people will therefore prefer to have a remote control. And, imagine that it is very far from being a constant on the most high-end devices. Indeed, few are those who offer it, unlike low-end models.

If you have decided to give your grandmother a robot vacuum cleaner to avoid this tedious task, you will find some models capable of controlling herself with a infrared or even radio-frequency remote control. They are not generally the most efficient, of course, but they have the advantage of being rather easy to use. In addition, if the device does not have a skill Alexa, you can still automate it via an infrared hub such as the Broadlink RM Pro + for example.

Editor's choice:

If you need a remote control, turn to the Deebot 500 series from Ecovacs Robotics, the unavoidable Proscenic 800T or 820T, or Cecotec robots such as the Conga 3690 Absolute or Conga 4090 !

Application: the geek's choice

Who says connected robot, says mobile application! Any robot vacuum cleaner worthy of the name indeed offers an application to control it. More or less ergonomic, it remains an important aspect. Indeed, some gave us the bad surprise of not responding or being excessively slow. In the long run, it is painful, it must be recognized. If some robots work with Smart Life, we were not really convinced by the latter. It is good for light bulbs and other connected objects, but clearly shows its limits when using a robot. This is the case with Proscenic or Cecotec robots: can do better. Likewise, Xiaomi Home is rather nice to use if you have a Roborock and want to group your devices, but if you don't mind that, do not hesitate to turn to the brand's home application, which is much more stable and effective.

Editor's choice:

Three applications stand out from the crowd in this area: Roborock, Neato and Ecovacs Home. These brands offer the most enjoyable and complete applications to our liking, automation possibilities, and compatibility with the main voice assistants on the market ... And in particular Alexa who was the first to know how to control robots, in this case the Neato D series Connected!

Navigation: optical cameras, infrared and laser telemetry ...

This is the most obvious aspect when you observe a robot vacuum cleaner at work: navigation. Several technologies are used, and the least we can say is that they produce very different results. We will move on to robots with random movements, which in our opinion are not interesting and already belong to the past, and will rather focus on the two most recent techniques: the systematic navigation and intelligent navigation.

These two types of navigation use sensors of all kinds. Sensors are essential to robot navigation and all are equipped with them, even the most basic. Indeed, the collection of information on the environment is a permanent quest in robotics. As our five senses allow us to evolve in space, a certain number of sensors will offer the robot the possibility of doing the same and of representing the environment in which it evolves (contact, odometry, sensitivity to light , sound, heat ...). The more we have, the better, because this allows the robot in particular to appreciate the distances, a fundamental datum, and make decisions based on obstacles or the absence of obstacles. It is telemetry, that is, the distance measurement of a distant point. Several types of sensors will be used for these measurements: infrared sensors, time-of-flight (TOF) sensors, ultrasonic sensors, lasers… And sometimes even optical cameras!

Sensors are essential to robot navigation and all are equipped with them, even the most basic. The Alexians

Infrared sensors

Usually placed under the robot, infrared sensors are used to measure distances and in particular to detect the vacuum. Inexpensive, there are at least three, sometimes six, or even twelve! It is thanks to them that your robot will not run down the stairs.

Positioned on the face and / or sideways, they then allow the robot to appreciate its distance from the walls and therefore to run along them as well as possible, to activate its side brushes to better clean the edges, or even to stop it in the face of obstacles that are too hard to avoid damaging it. They are effective but limited to distances of 1 to 80 cm depending on the model ...

Finally, they are used for the final approach to the charging station. This is why robots often have some sort of visor or front sensor, and the bases usually have a large black space on the front. The robot can thus appreciate its position in relation to the dock and come alone to take charge. But, if they are relatively precise, their field of action remains quite limited and they hardly exceed 80 cm of precision.

Ultrasonic radar or sonar

In order to find one's way in space, many robots also use ultrasound. This is the famous radar or sonar that we all know. These waves at frequencies exceeding 20 kHz are inaudible by humans and are generally around 40 kHz in the case of our robot vacuum cleaners. Ultrasonic sensors make it possible, like infrared sensors, to measure the distance that separates them from the various objects that they come into contact with. They are rather intended for the detection of moderately distant obstacles but do not allow a mapping as precise as the laser rangefinder.

Sensitive sensors

Placed under the bumper, on top of the device, or even directly at the wheels, these sensors allow the robot not to slow down when faced with an obstacle or to estimate whether it can pass under a piece of furniture without getting stuck in it. Integrated into the wheels, the sensitive sensors are also able to identify the type of coating in order to adapt the suction power. Thus, the robots with the most sensors will not run into obstacles, will not get stuck under a piece of furniture that is too low and will be able to increase their suction power on carpets and rugs. Among washers, this technology also allows some not to mop a carpet, but it is still far from being present in everyone.

The gyro sensor

The "platists" will hate robots! Indeed, the latter use gyro sensors that contradict their theory. Developed by Foucault in 1852 to demonstrate the rotation of the Earth, the gyroscope exploits the principle of conservation of angular momentum. The gyroscopic sensor is therefore an angular position sensor. Often it is actually a gyrometer, but we will not go into detail and only remember that it is used for measure changes in orientation and / or speed and rotation. They will make it possible to know that the robot has made a rotation of 90 ° to the right, a U-turn to 180 °, etc.

This sensor will be used to apply a cleaning scheme pre-programmed taking into account walls, furniture and empty spaces. The device will cut the space into distinct zones that it will then clean systematically. It is found on many mid-range robots, but it alone does not allow you to perform real mapping. If a map is correctly generated, it is only temporarily stored in the robot's RAM and is not kept, the robot will therefore have to re-analyze its environment at each cycle unlike those which also have a laser rangefinder on board ...

The laser rangefinder (LDS or LIDAR)

Laser range finding is the hottest technology these days, and that's hardly surprising. Indeed, LDS or LIDAR allows robot vacuum cleaners to better understand their environment. We recognize those who have it thanks to the turret which takes place on their upper face and which protects the optical system.

Composed of a laser and a lens to recover the signal, the rangefinder rotates continuously while the robot is walking and emits a laser beam allowing the device to collect a large amount of information on its surroundings, or to calculate distances with great precision. It is the most precise technology to date, the one that allows robots to map your home in the most precise way.

To fully understand how the laser rangefinder works, take a look at these few captures. Here, the Roborock S6 operates in the dark and our infrared surveillance camera perfectly highlights the operation of the sensors on the front of the robot, as well as the laser which leaves small points of light along the walls.

In the video below, you will also see two robots that do well in the dark. Well almost…

In addition to the small accident which makes you smile and is only the result of chance, you can see that the Roborock LDS (of which we also see the infrared sensors at work) as the infrared sensors of the Eufy RoboVac have the huge advantage of working even in the dark ... No need to remind your better half to leave the light on when leaving for the robot to do its job or to create a routine Alexa to turn off the light when the task is done!

The only defect observed to date: the laser rangefinder does not like mirrors too much too low or placed on the ground. Not really surprising since they reflect the laser beam! In the meantime, they stay less expensive than cameras which nevertheless have a future in front of it if we consider the next developments based on artificial intelligence.

The vision sensor and the optical camera

What if the easiest way was to give our robots a three-dimensional vision like ours?

Obviously, manufacturers have thought about it, but it is not necessarily the most efficient system, let alone the most affordable. If you are worried about being observed by your robot, rest assured, most are actually not really capable of it. Some use simple vision sensors which just allow model the environment in 2D or 3D in the form of a diagram, others have more precise cameras but do not record the images at all, they just set benchmarks. This is particularly the case of the iAdapt® localization camera embedded on iRobot vacuum cleaners. It does not save videos or images which therefore cannot be shared. Phew!

Like the laser rangefinder, the optical camera therefore makes it possible to map with precision housing and offers the advantage of seeing further. However, since robot vacuum cleaners are intended for closed environments, this advantage should be put into perspective, especially since video requires much more software processing and therefore more powerful hardware, which does not fail to add to the final bill. At last, they have the enormous disadvantage of being unusable in the dark. Indeed, like humans, optical camera robots are not nyctalopic. It's a shame, especially since the simplest robots or laser rangefinders do well in the dark. Well, almost always ...

Editor's choice:

If the most basic robots are satisfied with a single technology, generally infrared sensors, the most advanced readily use several, some even mixing almost all of them (infrared sensors, gyroscope, accelerometer, sensitive sensors, sonar and Lidar, yes yes !). We therefore advise you to turn to a robot equipped with a laser rangefinder., the most reliable and proven technology, pending the arrival of artificial intelligence ...

Artificial intelligence: a little today, a lot tomorrow ...

Let's close this file with an opening to the future the very news of robots! A future more than near since the first robot vacuum cleaners equipped with artificial intelligence are already there and their marketing in Europe will take place within a few weeks. We think in particular of the AIVI ™ technology that the Chinese company Ecovacs Robotics has just integrated into its brand new Deebot Ozmo T8 AIVI which already succeeds the Deebot Ozmo 960!

Thanks to a camera, the robot vacuum cleaner is in fact able toidentify objects. An innovation that uses artificial intelligence and in particular machine learning. The robot is thus able to recognize each element of a scene and to label the objects: slipper, chair, table, etc.

Roborock is also no exception and has even followed in the footsteps of its competitor in Europe by offering a last iteration of its very successful top of the range: the Roborock S6 MaxV. A robot offering a dual camera module and capable, too, of recognizing the objects that he crosses on the way. Currently in test in our lab ', we are impatiently awaiting the T8 AIVI to know which of the two will be LE best robot vacuum cleaner, because there is no doubt: the match is currently taking place between these two models (it is June 5, 2020).

After autonomous cars, it is therefore our small household robots that will, in the years to come, be equipped withartificial intelligence. We might as well tell you that, at Les Alexiens, we will obviously be following all these fascinating developments very closely and that we will not fail to tell you about them very soon!




Fascinated by Alexa since the day I received it in beta test, I gradually became passionate about the subject, before deciding to go further by creating a site with Jean-Christophe. An activity that allows me to quench my thirst for new technologies and share my discoveries about the nicest of communities: Les Alexiens.