Sensing odour sources in indoor environments without a constant airflow by a mobile robot

A mobile robot with gas sensors commonly denoted as 'electronic nose' enables some interesting applications including the development of an 'electronic watchman' that is able to detect and localize odour sources. This paper describes the assembly of a mobile odour sensing system and presents investigations on its practical operation in an indoor environment without a constant airflow¹. Lacking a constant airflow leads to a problem which cannot be neglected in real world applications. In this case the response of the used metal oxide gas sensors is dominated by air turbulence rather than concentration differences. In the following article we show that this kind of problem could be overcome by driving the robot with a constant speed, thus adding an extra constant airflow relative to the gas sensors location. If the robot's speed is not too low the described system proved to be well suited to detect even weak odour sources. Because driving with constant speed is an indispensable condition to perf orm the basic tasks of a mobile odour sensing system, a new localization strategy is proposed, which takes this into account.