Abstract
This study explored robot vacuum cleaners' meaning to humans as moving artifacts in the environment. We visited
households where robot vacuum cleaners were used and observed and accompanied robots as they cleaned. We
recorded the robots' movements, contact with the environment, and human actions. The organization and analysis
of the data indicated the following. (1) Robots contact objects, especially light and movable objects, and humans as
natural objects and create a new environment. (2) Robots' environment consists only of the physical environment,
whereas the human environment consists of physical and psychological factors. (3) Robots are included in the
human-home system, which develops human consideration of the human-robot-home system. We have discussed
possible methods of understanding humans by observing robots.
