Non-visual orientation and communication by fishes using electrical fields: A model system for underwater robotics

Building autonomous underwater robots is a challenging problem. Different sensory modalities have been employed successfully, some inspired by human and animal senses. The European ANGELS project uses an electric sense inspired by weakly electric fish. These fish have the unique ability to navigate and orient in complete darkness by using self-produced electrical fields. They emit electric signals into the environment, which in turn they perceive with an array of electroreceptor organs in their skin. The fish´s whole body serves as an antenna, which shapes the emitted electrical field. As a result, the animals are able to detect, localize and analyze objects in their vicinity and to perceive a 3-dimensional electrical picture of their surroundings. Here, we review biological experimental results highlighting the animal´s perceptual abilities, which allow them to navigate in extreme environments where vision can not be used. In addition, electric fishes use electric signals for communication. Behavioral communication strategies such as synchronization of electric signals and fixed-order-signaling can play a role in group coherence. Because of their unique sensory abilities, electric fish can serve as a model system for roboticists building underwater vehicles that can communicate and navigate in extreme environments where vision is not possible. In ANGELS, the electric sense is used to navigate a robot without knowledge of the surroundings, keep multi robots in formation, reconstruct an image of the environment and communicate between different robots - all inspired by our biological investigations.