Moth-inspired plume tracing via autonomous underwaer vehicle with only a pair of separated chemical sensors

Effective chemical plume tracing strategies are important for autonomous underwater vehicles (AUVs) to perform a variety of missions of searching for underwater targets, such as oil spill sources and deep-sea hydrothermal vents. In such circumstances where fluid flow direction cannot be measured by AUVs or fluid flow direction provides little or wrong information about the distribution of a dynamic chemical plume or its source location, chemical plume tracing strategies that rely on information of fluid flow direction may not work effectively. In this paper, a modified moth-inspired chemical plume tracing strategy is presented, which could trace a turbulent chemical plume without need of information of flow direction. The strategy estimates the direction of plume centerline based on information from a pair of spatially separated chemical sensors symmetrically mounted on an AUV´s nose together with the AUV´s zigzag plume-tracing trajectory, and employs the estimated direction of plume centerline to implement the plume tracing. The proposed strategy is implemented in a computer simulation environment and the simulation results demonstrate that with the strategy an AUV could track a turbulent chemical plume over a long distance and finally localize the plume source.