A Robot Vacuum Is A Navigation Problem With A Dustbin

Robot vacuums are marketed with suction figures, which are the least useful way to tell them apart. What separates them is how they understand a room and what they do when they are wrong.

Coverage matters more than suction

A robot has a small motor, a small battery and a small bin, so it cannot compete with an upright on any single pass. It compensates by running often.

That model only works if the machine covers the whole floor. A powerful robot that misses a third of a room is a worse cleaner than a weak one that covers all of it.

Coverage is a navigation property, which is why two machines with identical stated suction produce visibly different results in the same house.

Navigation methods differ in what they can plan

The simplest robots move semi-randomly and rely on time to reach everywhere. They eventually cover a small open room and fail badly in a house with several rooms.

Mapping robots build a floor plan, usually with a spinning laser rangefinder or with cameras, and then drive in systematic rows and track what they have already done.

A map also enables the features owners actually use: cleaning a named room, excluding an area, and resuming in the right place after returning to charge.

Failure recovery is the real quality difference

Every robot gets stuck. What varies is whether it recognizes it, frees itself, and continues, or sits under a couch until someone finds it.

Common traps are cables, rug tassels, thresholds and dark floors that a cliff sensor reads as a drop. Robots differ enormously in how they handle each.

The practical test of a machine is not its first run but its twentieth, because by then the household has learned what to move and the machine's remaining failures are the ones it cannot solve.

The bin and the brush set the maintenance load

Bin capacity is small, so a robot on a large floor fills before it finishes. Self-emptying bases move that problem to a larger container and add a consumable bag.

Brush design decides how much hair wraps around the roller, and the difference between a bristle brush and a rubber one shows up in a household with long hair or pets.

Filters load quickly for their size, and a loaded filter cuts airflow on a machine that had little to spare. This is routine maintenance rather than an occasional task.

Mopping robots are wiping, not scrubbing

A pad dragged across a floor under the weight of a small machine removes light film. It does not remove anything dried or sticky, and expectations set by the marketing rarely match this.

Machines that lift the pad for carpet, wash the pad in the base, or vibrate it against the floor are addressing genuine limitations of the basic arrangement.

What none of them change is the pressure available, which is set by the weight of a machine that also has to fit under furniture.