How Robotic Vacuum Cleaners Work

How Robotic Vacuum Cleaners Work

Last Updated on by Daniel Lawrence

The era of hiring a nanny to clean your home is gradually fading away. Technology has brought the use of robotic vacuum cleaners. You may want to know how they work. This guide will tell you that in detail, you just have to read through to the end, and you’ll find the answers you seek.

What Is A Robotic Vacuum Cleaner?

A robotic vacuum cleaner sometimes called a robovac or a Roomba as a generic trademark is an autonomous robotic vacuum cleaner that has a limited vacuum floor cleaning system combined with sensors and robotic drives with programmable controllers and cleaning routines. Early designs included manual operation via remote control and a “self-drive” mode which allowed the machine to clean autonomously without human control.

Some designs use spinning brushes to reach tight corners, and some include several cleaning features along with the vacuuming feature (mopping, UV sterilization, etc.).[2] More recent models use artificial intelligence and deep learning for better mapping, object identification, and event-based cleaning.

Marketing materials for robotic vacuums frequently cite low noise, ease of use, and autonomous cleaning as main advantages. The perception that these devices are set-and-forget solutions is widespread but not always correct.

Robotic vacuums are usually smaller than traditional upright vacuums and weigh significantly less than even the lightest canister models. However, a downside to a robotic vacuum cleaner is that it takes an extended amount of time to vacuum an area due to its size. They are also relatively expensive, and replacement parts and batteries can contribute significantly to their operating cost.

Main features

  • Cleaning modes

Robotic vacuum has different types of cleaning modes, usually include the following:

  • Auto: This mode is helpful for general cleaning. Usually, the mode cleans a space until the battery runs out.
  • Spot: with the help of this mode, the vacuum focus on a particular dirty zone.
  • Turbo: This mode is used to clean and pick up the most dirt and dust, but it may create noise.
  • Edge: This mode helps to clean edges & corners.
  • Quiet: The model helps to reduce noise levels while cleaning. It’s helpful when you are at home.
  • Remote control: It allows the user to control the direction of the vacuum.
  • Wet mopping

Some models can also mop for wet cleaning, autonomously vacuuming, and wet-mopping a floor in one pass (sweep and mop combo).

The mop is either manually wetted before attachment to the bottom of the robot or the robot may be able to automatically spray water onto the floor before running over it.

Some advanced robot vacuum cleaners have a sensor that detects and avoid mopping in carpeted areas. However, if there is no sensor, most of the robot vacuum cleaner manufacturers adding a no-mop zone feature in the app nowadays to make robot vacuums to avoid certain areas from mopping. These robot vacuums are also capable to mop about 150sqm in one go.

A Robot Mop can tackle multi surfaces and comes with a variety of different cleaning modes giving you options of sweeping, vacuuming, and mopping damp or wet floors. The Robot Mop score better on hard floors surface and are ideally suited for hardwood, laminate and tile flooring types

  • Anti-drop

Most robots include anti-drop and anti-bump IR sensors.

  • Anti-winding

When approaching obstacles, will automatically turn away.

  • Antitwining

Prevents the robot from getting twined by wires.

  • Mapping

The first robovacs used random navigation. This sometimes caused the unit to miss spots when cleaning or be unable to locate its base station to recharge, and did not provide the user a history of which spaces were cleaned.

More sophisticated models include mapping ability. The unit can use gyro, camera, radar, and laser (laser distance sensor or LDS) guided systems to create a floor plan, which can be permanently stored for more efficiency, and updated with information on areas that have been (or have not been) cleaned. Thus, the cleaning efficiency is greatly improved and the repetition rate is reduced significantly.

Mapping delivers significant advantages. Armed with a floor plan, the robot vacuum can plot the most efficient route through the room, which is why mapping models seem to move in more orderly straight lines than their non-mapping counterparts.

Mapping also allows the robot vac to localize itself within the map, which informs it where it’s been and where it yet needs to go. And if the vacuum’s battery runs low partway through the job, it can return to its dock to recharge, and then pick up where it left off. The result of all this is a quicker, more thorough, and even cleaning.

Models with a multiple floor plan feature can store several floor plans.

  • Virtual No-Go lines

Virtual No-Go lines set boundaries, to restrict the unit’s movements to desired cleaning areas.

  • Quick recharge

Most robot vacuums come with a Lithium-ion battery of around 2000 mAh that will last long enough to handle approximately 200 m2 of floor space (about 100 minutes).

  • The regular charge time is 5 to 6 hours.

Quick recharge allows the unit to calculate the shortest way to recharge (shortcut path) and charge only as much as needed, so it finishes more quickly (automatic cleaning resumption).

  • Schedule

Scheduled daily cleaning. All-Timetable means a full week of different daily schedules can be programmed.

How a robot vacuum sees the world

Robotic vacuum cleaners don’t use cameras to see the world. Instead, they use various types of sensors to detect and measure the worlds around them and their own progress through it, including cliff sensors, bump sensors, wall sensors, and optical encoders.

Cliff sensors measure the distance between the robot base and the floor, usually by bouncing infrared light off the floor. If there is a sudden increase in the distance to the floor, that means the robot is getting close to a stair edge or something similar, so it will back off to avoid falling over it (hence the “cliff sensor” name).

The name of the bump sensors also gives away what they do: if the robot vacuum bumps into something (like a wall or a chair leg), the impact triggers the sensor. Wall sensors are like cliff sensors, but in a different direction: they tell the robot when it is close to a wall or other object, so it can follow the wall.

Optical encoders are the most important: these sensors on the wheels of the robot tell it how far it has gone. They are called optical encoders because they use a light sensor to detect how many times the wheels have rotated. From this (and any difference between wheels, which indicates a turn), the robot can figure out how far it has traveled.

Different models may include additional sensors (such as a dust scanner to see how much dust is being picked up), but those are the basic sensors that all robotic vacuums include.

This combination of sensors means that the robot knows a few things about the world around it: how far it has gone, things it has bumped into, and things it could fall off from. These are the things that a basic robot vacuum will need to know to navigate the world around it.

The limitations of robot vacuums

Before you start thinking that autonomous vacuums are the secret ingredient to an always clean home, we should go over several limitations. Let’s say that robot vacuums won’t be replacing your stand-up vacuum anytime soon.

First, robot vacuums don’t have the same cleaning power and maneuverability that you find with a traditional upright unit. While most units have a varying amount of suction, most designs do not allow the vacuum to reach every inch of floor in your home.

Second, robot vacuums have sensors to make sure they don’t roll down the stairs, but there isn’t much stopping them from sucking up small items in cluttered environments. The biggest casualties in my experience are cables. While most vacuums will move right over thicker cords for lights, USB-C and Lightning cables can get mangled and destroyed.

There are day-to-day hassles with robot vacuum cleaners too. For one, the smaller design doesn’t allow for that large of a collection bin. While it might take a couple of days to fill up if used regularly, homes with pets might need to empty the bin a lot more consistently, which can be a pain over the long term.

The other daily hassle is charging. Each robot vacuum will have a battery size rated for an hour or so of continuous cleaning, but the units aren’t always the best at making it back to their charging station. Some days, you might find your vacuum in the middle of a room chirping that it needs to be charged.


No robot vacuum will navigate flawlessly all the time. You’ll sometimes have to detangle them from cords or extract them from a low couch they never should have gone under, to begin with. Ultimately, which navigation method your robot vacuum uses doesn’t matter as much its ability to clean your floors to your satisfaction with a minimum of help from you. But the next time your vacuums navigation has you scratching your head, remember that there’s probably a method to its madness.