Odor-source location estimation and search using a movable sensor array

Using mobile robot with onboard gas and wind sensors to estimate and search hazardous gas/odor source has great application prospect. This paper presents an odor-source localization (OSL) method using a mobile robot equipped with a gas sensor array (we call it movable sensor array for short) in both indoor and outdoor environments. Six gas sensors and one wind sensor are placed at the circumference and the center of a circle, respectively. Based on the assumption that the wind is uniform in a small area, at each iteration cycle, the robot is controlled to move a step toward the source location estimated by fusing the sensors´ data. The source location is calculated by solving nonlinear least square equation with Levenberg-Marquardt algorithm. The odor source is declared by combing a spiral motion and heuristic idea. The proposed OSL method has been evaluated in both indoor and outdoor simulation plume platforms. Simulation results show that the movable sensor array is able to find the odor-source location with a small error, but the success rate is related to the arrangement of sensor array and motion step.