Research On Chemical Plume Tracing And Mapping With Autonomous Underwater Vehicles

In recent years,marine oil spill accidents occur frequently.The oil spill plumes not only have significant impact on the marine environments but also on human lives.In order to effectively deal with the oil spill plumes and assess their impacts,obtaining the information about the spatial and temporal distribution of the oil spill plumes is required.Autonomous underwater vehicles(AUVs)are important tools to efficiently collect high-resolution data of underwater oil spill plumes and have been employed in many practical applications.Transported by ocean currents changing with both time and location,oil spill plumes are typical dynamic features in the oceans.In order to efficiently sample the dynamic oil spill plumes,on-line planning is significant to enable an AUV to react to its real-time sensor data to plan its path to efficiently track a plume and collect its tracer data.Finically supported by the project of National Natural Science Foundation of China(Grant No.41376110)and the project of State Key Laboratory of Robotics at Shenyang Institute of Automation,Chinese Academy of Sciences(Grant No.2012-Z04),this thesis conducts research on the on-line planning issue and develops effective planning method and algorithms.The primary work and results of thesis are as follows.(1)Based on the results of the moth-inspired chemical plume tracing with autonomous robots,a plume tracing and mapping strategy is proposed,and a behavior-based planning algorithm is developed to implement the strategy.(2)Using the Kriging method in Geostatistics,a strategy is developed to enable an AUV to optimize its plume mapping trajectories to improve the efficiency of the developed behavior-based plume tracing and mapping strategy.(3)By employing data-driven ocean current modeling and prediction,together with the Lagrangian particle random walk algorithm for simulating a dynamic turbulent plume,a strategy of estimating the center-line of the plume to be tracked and mapped is proposed,to enable the developed behavior-based planning strategy be able to have track-lines being perpendicular to the plume centerline other than the mean flow direction.The research results in thesis provide solid foundation for future applications of AUVs in oil spill plume tracking and mapping missions.