LAUSR

Accurate pose estimation and localization technology is always a challenge for small underwater robots, since the underwater lighting conditions could limit the use of cameras while the cramped environments restrict the use of sonars. In nature, some fishes perceive other creatures by sensing the weakly changes in their environmental electric field. Inspired by such passive electric sense behavior in fish, this letter presents an electro-localization scheme based on passive electric sense for short-distance accurate pose estimation and localization of small underwater robots. Our scheme includes a hardware solution to the electric sense and a pose estimation method. Specifically, first, we design a hardware solution including an electric emitter placed in the underwater environment and an electric receiver that can be carried by a small underwater robot. Then we construct the theoretical model of the electric field generated by our designed hardware. Finally, we propose an electric sense based method to estimate the position and orientation of the free-swimming robot, where a particle filter is utilized to combine the odometer and electric sense based measurements while the dynamic model of the robot is also included. Localization experiments for the small underwater robot equipped with the electric receiver are conducted, and the experimental results demonstrate the robustness and effectiveness of our proposed electric sense based pose estimation approach, especially in position estimation.