SIREN: Underwater Robot-to-Human Communication Using Audio

In this letter, we present SIREN: a novel audio-based communication system for underwater human-robot interaction. SIREN utilizes a surface transducer to produce sound by vibrating the frame of an underwater robot, essentially turning the robot's outer surface into the vibrating membrane of a speaker. We employ this hardware in two forms of robot-to-human communication: synthesized text-to-speech (TTS-sonemes) and synthesized musical indicators (Tone-sonemes). To profile the system's capabilities with respect to underwater communication, we perform a substantial in-person human study with 12 participants. In this study, participants were trained on the use of one of the previously mentioned audio communication systems. Participants were then asked to identify the communication from their system in a pool at various distances. This study's results demonstrate that sound is a viable method of underwater communication. TTS-Sonemes outperform Tonal-Sonemes at close distances but fail at further distances, while Tonal-Sonemes remain recognizable as the distance to the robot increases.