Recently, the research team led by Professor Guangming Xie from College of Engineering of Peking University has developed a bio-inspired electrocommunication system, providing a new insight for underwater communication. The research paper was published in the Bioinspiration & Biomimetics, the leading journal in the field of bionics.
Due to the particularity of the water medium, communication is still challenging for underwater robots, and it has restricted to some extent the large-scale applications of underwater robots. At present, acoustic communication is the most popular method within the underwater robotics community. However, it is a typically low-speed communication and could be easily affected by the water movements and the surrounding obstacles. Moreover, acoustic communication has problems of large doppler shifts and multi-path effects when robots are engaged in highly confined aquatic environments (e.g. shallow waters, narrow pipes, tunnels and caves. Therefore, it is hard for acoustic communication to meet the increasing requirements of underwater communication. Underwater communication has been one of the research hotspots in the field of underwater robots in recent years, and has attracted more and more attentions in the world.
Prof. Guangming Xie’s group has rich experience in the interactions between robots and biological behaviors, and has contributed several novel advances in the field of bio-robotics. Recently, inspired by the communication behavior in some kinds of fishes, Prof. Xie’s group developed a novel underwater electrocommunication system which is stable, low-power consumption and robust against water environment changes.
Xie’s group found that several hundreds of fish species of the Gymnotid and Mormyrid families (collectively known as weakly electric fishes) have developed the ability to produce and perceive electric signals, similar to active sensing systems like radar and sonar. In particular, electric fishes communicate electrically (termed electrocommunication) by one fish generating an electric field and a second individual receiving that electric field with its electroreceptors and decoding the information with its nervous system. These electric signals are generated by a specific organ called electric organ discharge (EOD) in weakly electric fishes. Signal frequencies, waveforms and time delay can be identified in electrocommunication. Inspired by this biological phenomenon, Xie’s group started to abstract and simplify this electrocommunication as an electric dipole system, then they investigated its distribution characteristics through simulation, and finally designed such an artificial electrocommunication system for underwater robots. Further, the research groups characterized the communication performance of the robot in still water, flowing water, water with obstacles and natural water conditions. The results have shown that electrocommunication is more stable than acoustic communication and it is almost free of water movements, obstacles and water qualities. The robot is able to communicate electrically at a speed of around 1k baud within about 3~5 meters with a low power consumption (less than 1 W). In addition, they have demonstrated that two leader-follower robots successfully achieve motion synchronization through electrocommunication in the three-dimensional underwater space, indicating that this bio-inspired electrocommunication system is a promising setup for the interaction of underwater robots. This work has been published in the Bioinspiration & Biomimetics (W. Wang, J. Liu, G. Xie, L. Wen, and J. Zhang, “A Bio-inspired Electrocommunication System for Small Underwater Robots”, Bioinspiration & Biomimetics, 12, 036002, 2017.).
The corresponding author of the paper is Prof. Guangming Xie. The first author is Dr. Wei Wang in Prof. Xie’s group. This project is supported financially by the National Natural Science Foundation of China (NSFC). The collaborator of the project also includes Prof. Jianwei Zhang at University of Hamburg, Germany, Prof. Jindong Liu at Imperial College London, the United Kingdom, and Prof. Li Wen at Beihang Univercity.