Domain-specific languages: a gesture-based approach for Human Robot Interaction in underwater environments

This paper introduces a gesture-based language for Human Robot Interaction (HRI) specifically aimed to divers. Divers generally operate in environments with harsh conditions and, at the same time, difficult to monitor; in this scenario, any sudden event can create an emergency situation that may compromise the immersion or even turns into worse consequences involving the safety of divers themselves. To cope with such situations, standard procedures suggest to dive in pairs and to follow well-defined rules to avoid the risk of accidents. However, these procedures may not be sufficient to avoid dangerous events such as failure in the breathing apparatus, burst eardrum, decompression sickness and nitrogen narcosis. FP7 CADDY project was developed to overcome these problems, with the idea to transfer robotics technology in diving: the main aim is improving the level of safety during diving. CADDY project focuses, in fact, on the development of a companion robot designed to support human operations and activities during the dive, as well as to monitor the status of the diver and in such a way to prevent harmful events. Various problems have to be confronted to provide the diver a reliable and useful supporting robotic vehicle: one of them is the development of a communication and interaction methodology that allows the diver and the robot to cooperate actively for the fulfilment of tasks required when diving. Communication and correct reception of messages between the diver and underwater robot are essential for the success of the objectives of immersion. However, the underwater environment poses a number of difficult technical constraints limiting the possibilities of communication (electro-magnetic waves strong attenuation and signal scattering and dispersion). The most reliable solution for underwater communication is acoustic technology, with two main drawbacks: high prices of devices and very low data rates. To solve these issues, the solution proposed is the development of acommunication language (called CADDIAN) based, partly, on the consolidated and standardized diver gestures that are commonly employed during professional and recreational dives.