Obstacle effects on electrocommunication with applications to object detection of underwater robots.

Some fish species communicate electrically (termed electrocommunication) in turbid waters where other communication modalities fail. Inspired by this biological phenomenon, we have developed an artificial electrocommunication system for underwater robots (Wang et al 2017 Bioinspir. Biomimetics 12 036002). Due to the complex terrain of the ocean, electrocommunication could be affected by potential obstacles. In this paper, we investigate the obstacle effects on electrocommunication in a quasi-two-dimensional water environment. We first employ Fresnel zone theory to theoretically analyze the obstacle effects on electrocommunication. We then simplify the ocean terrain into 32 types of obstacles according to their material, relative location, geometry, and size, and use ANSYS Maxwell to simulate the effect of these obstacles on electrocommunication. We fabricate the same types of obstacles as in the simulation, and further conduct electrocommunication experiments with these obstacles in a swimming pool. Both the simulations and experiments show that the material, relative location, geometry, and size of the obstacles all affect the electrocommunication to varying degrees. Finally, we demonstrate that it is possible to identify and detect underwater objects based on the obtained obstacle effects, indicating that electrocommunication could be a new viable method for underwater object detection.