What Robots Can't Clean

Stairs and changes of level

Stairs remain a research problem for cleaning robots. Researchers described sTetro-D, a robot that cleans stairs while descending them, in Engineering Applications of Artificial Intelligence in 2023. They noted that earlier staircase cleaners focused on climbing, which raises power use and makes full coverage of a multistorey building hard, and their prototype reported 85% detection accuracy and 98% area coverage in tests. Those are encouraging results from a research team, not a product you can schedule tomorrow. For now, plan to carry floor robots between levels, or use lifts where the robot can work them, and keep stairs, ramps and landings on a manual round with its own checklist.

Washrooms and fixtures stay manual

Toilets, basins and urinals combine awkward shapes, splashes and hygiene risk, and people already clean them quickly and at low cost. Writing in IEEE Spectrum in 2018, Evan Ackerman argued that this economic fact, more than the engineering, is the main obstacle to bathroom robots. The research robot in his report, a TIAGo mobile manipulator programmed at the University of Koblenz-Landau, could find and wipe a toilet seat and pick up rubbish, but it was not fast. Floor scrubbers can still do washroom floors where the layout allows. Budget for people to clean fixtures, restock consumables and carry out the hygiene checks those rooms need.

Clutter, cables and objects on the floor

A robot that meets a bag, a cable or a toy can only avoid it, stop or push it along, because picking things up is still beyond cleaning machines on the market. In a 2023 IEEE Spectrum discussion of domestic robots, iRobot's chief technology officer Chris Jones called grasping objects and opening doors the 'Holy Grail' of home robotics. He also warned of a long tail of corner cases, and said that if a failure happens often enough, users stop using the product. In offices and homes, that makes a quick tidy before each run part of the job. Set no-go zones around cable clusters and plant pots, and keep a note of where runs stall.

Edges, corners and detail work

Round robots can leave a margin in corners, square ones may still miss the space behind doors and around table legs, and a scrubber's squeegee often stops short of the last strip along a skirting board. Spills that appear mid-shift, chewing gum, high-level dust, desks and glass partitions all need a person too. Plan a short detail round that follows the robot's route and finishes what it cannot, and judge the combined result rather than the machine alone. When you compare models, ask each maker to demonstrate edge cleaning on your own floor and furniture, and photograph what is left. That evidence helps you size the manual hours that remain once the robot starts work.

Sources and further reading

• sTetro-D: a deep learning based autonomous descending-stair cleaning robot — Engineering Applications of Artificial Intelligence (ScienceDirect).
  Research prototype for cleaning stairs while descending, with test results and the limits of climbing designs.
• Creating domestic robots that really help — IEEE Spectrum.
  Roboticists from iRobot and Labrador Systems on clutter, grasping and the corner cases that defeat home robots.
• Robots finally learning to clean the bathroom — IEEE Spectrum.
  Report on a research robot wiping toilet seats, and why bathrooms remain an economic challenge for robots.

Common questions

Can a cleaning robot get under beds and sofas?

Only where the gap is taller than the robot and the floor beneath is clear. Measure the lowest sofa and bed bases against each model's stated height, move items stored underneath, and expect a person to reach the back corners now and then with a hand tool.

Will cleaning robots replace cleaners?

They change the job more than they remove it. Robots take over long, repetitive passes on open floors, while people handle washrooms, edges, spills, inspections and the robots themselves, including emptying, refilling and clearing faults. Plan rotas around that split rather than around a brochure's promises.