A robot vacuum usually gets stuck because it met something it cannot move, climb or see past. Loose cables, raised rug edges and tight corners are common trouble spots. A robot cannot pick a chair up or push a toy aside the way a person can, because the vast majority have no arms.
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WIRED’s reviewers put it bluntly. Makers will tell you suction power matters most, but the real test is whether the robot wedges itself under the same corner and dies on every run.
Why cables and socks stop it
Loose cables are the classic trap. Engadget notes that they can wrap round a robot’s brushes or wheels and halt it before it finishes a run. Socks can get sucked in, and so can lightweight rugs.
An anti-tangle brush does not solve this. A spokesperson for iRobot, the company behind Roomba, told Yahoo Tech that power cords can still catch, and asked owners to gather them up first. The same spokesperson warned that a robot can drag a kitchen mat around unless the mat is tidied away or held down with anti-slip backing.
Why floors trip it up
Floors are rarely flat. Tiles, rugs, carpets and wooden boards meet at edges and thresholds. A raised rug edge, or a doorway between wood and carpet, is where a robot tends to beach itself. Once it is stuck, Engadget points out, its suction figure no longer matters.
High-pile carpet, shaggy rugs and bath mats cause the same trouble. Yahoo Tech suggests ramps or transition strips where one floor type meets another. It also advises checking the wheels and brushes for tangled fibres.
Corners are the other lasting problem. Most robots are round, with the main brush underneath, so a tight corner stays hard to clean even with side brushes. Stairs are out of reach. Roborock has shown prototypes that can climb stairs, but none is on sale.
Why navigation decides so much
How a robot finds its way sets how often it gets lost. The cheapest models use bump sensors, so they have to hit something before they turn. That can leave them working the same patch again and again against a barrier. Better models add infrared sensors, and the most expensive use lidar and AI cameras to read the room.
WIRED ranks the systems the same way. Bounce navigation uses sensors round the outside of the robot to ping-pong it through the house. Lidar uses pulsed lasers to pin down where the vacuum is. The Matic robot, which WIRED rated 10 out of 10, uses six RGB cameras to build a 3D map of the house. WIRED called Roborock’s lidar-style system the second most reliable it had used.
A more complex system costs more. Even so, Engadget found that the best models still cannot deal well with every obstacle.
Why a dirty robot loses its way
Dust on the sensors can stop a robot reading its surroundings. Yahoo Tech lists four kinds of sensor on a typical model:
- obstacle sensors, infrared or ultrasonic, that spot furniture
- cliff sensors that keep it off stairs and ledges
- bump sensors that register a collision and turn it
- camera or lidar sensors that map the room
Wiping them with a soft microfibre cloth, and clearing hair from the wheels, keeps it moving. Yahoo Tech also blames some stalls on a flat or faulty battery. It advises a full charge before each run, and cleaning the charging contacts on the robot and its base at least monthly.
What helps before you press start
The fix most sources agree on is the dullest one. Clear the floor first. Engadget says owners still need to check for cables, toys and pet mess before a run, however good the robot.
Where a spot keeps catching it, Yahoo Tech suggests a no-go zone in the app, or magnetic strips and boundary tape along furniture edges. WIRED’s advice starts earlier, at the shop. Buy for your own home, because a friend with one low sofa may need a very different robot.
