Chemical sampling device for underwater robot: Jet discharge mimicking crayfish

Here we report on active water sampling devices for underwater chemical sensing robots. Crayfish generate jet-like water currents during food search by waving the flagella of their maxillipeds. The jets generated toward their sides induce an inflow from the surroundings to the jets. Odor sample collection from the surroundings to their olfactory organs is promoted by the generated inflow. Devices that model the jet discharge of crayfish have been developed to investigate the effectiveness of the active chemical sampling. Experimental results are presented to confirm that water samples are drawn to the chemical sensors from the surroundings more rapidly by using the axisymmetric flow field generated by the jet discharge than by centrosymmetric flow field generated by simple water suction. Results are also presented to show that there is a tradeoff between the angular range of chemical sample collection and the sample collection time.