It will recharge and complete the cleaning cycle. You can set the app to Sleep mode to prevent that happening in the night.

Learning about the home

It has a self-learning function and SLAM (simultaneous localisation and mapping) function as well as smart self-learning and recognition technology. Yet I cannot find a home map in the app after two full vacuums.

You know its learning because when you place it somewhere new, it says it does not recognise the area and starts learning.

LG R9 Master

It has a 3D dual eye laser sensor to detect objects (which is far better than a mechanical bumper in some vacuums) and smart turbo to increase/decrease suction on different floor surfaces.

Note you do not need to install the LG ThinQ app – the remote control will access all features, but you will not see cleaning logs etc.

A 2.4Ghz Wi-Fi connection facilitates communication with the app, but you don’t need it to clean the home. However, a low or no signal may stop it from returning to base.

Floor surfaces

The R9 Master is the only robot vac so far that has negotiated and cleaned our feature shag pile rug. The shag is over 25mm long and has some longer contrast threads as well.

LG R9 Master

It ploughed over the edge (25mm) and started cleaning without missing a beat.

Earlier we said it was as good as the LG A9 Master stick vac in terms of a deep clean. The bare-foot test showed a grit and dust-free surface that was a pleasure to walk on.

Preparation for cleaning – a major issue for all robot vacs

You cannot expect any robot cleaner to just to work! As a guide

  • Lift all chairs off the ground (if you want it to clean under tables)
  • Lift floor rugs with tassels that could get tangled in the brush
  • Tie up loose electrical cables from the floor
  • Remove clothes/shoes/bags on the floor
  • Build lower gradient ramps if the door sill is over 20mm (if you want it to clean in those areas)
  • Close doors to areas you don’t want it to clean

Having said that, this is the first vacuum that I feel confident that you could skip the preparation, and it would still do the job. Its obstacle detection is brilliant – far better than vacs using physical bumpers.


It defaults to a zig-zag mode. Like any other robot vac, it reverses out of the charger, does a U-turn and heads in a ‘north/south’ direction until it encounters an obstacle and then reverses and starts again. It’s very much faster than others as it has a full-width motorised head and it moves so much faster.

It also has edge mode where it will navigate around the edges – we tested that, and it uses the 3D Laser to map the walls and gently ‘suck up’ to them engaging turbo on close approach to ensure a good clean.

You can also use the remote or the app to direct it to a specific area. It also has a spiral spot clean mode.

Maximum obstruction sill height

It handles up to 25mm sills with ease – something no other review bot has done.