Experimental analysis of smelling Braitenberg vehicles

Abstract

This paper addresses the problem of localisation of a static odour source in an unstructured indoor environment by a mobile robot using electrochemical gas sensors. In particular, reactive localisation strategies based on the instantaneously measured spatial concentration gradient are considered. In contrast to previous works, the environment is not artificially ventilated to produce a strong constant airflow, and thus the distribution of the odour molecules is dominated by turbulence. An experimental set-up is presented that enables different strategies for odour source localisation to be compared directly in a precisely measured experiment. Two alternative strategies that utilise a direct sensor-motor coupling are then investigated and a detailed numerical analysis of the results is presented, including tests of statistical significance. Both tested strategies proved to be useful to accomplish the localisation task. As a possible solution to the problem of detecting that the odour source - which is usually not corresponding to the global concentration maximum - was found, one of the tested strategies exploits the fact that local concentration maxima occur more frequently near the odour source compared to distant regions