Abstract:

The study and experimentation of communications (e.g. network protocols) in underwater scenarios requires managing multiple expensive hardware elements, such as ROVs (Remote Operated Vehicle), modems and sensors, all of them assembled and integrated in an appropriate manner. In addition, the real scenarios at sea are not appropriate for robotics and communications students, in order to perform their first exercises in a more comfortable manner. In addition, real experiments at sea are not appropriate for robotics and communications students, in order to perform their first exercises in a comfortable manner. The complexity of dealing with all the required equipment requires the existence of a tool that allows to simulate all the components of a scenario with robots and submarine communication links.

Previous education experiments in this field allowed the creation of the UWSim underwater simulator. It permits the students to learn via web and also off-line the way robotics techniques can be applied in real scenarios. However, there is no educational tool that permits the students to work on both, robotics and also communications technologies, which in fact are very much related in order to allow the implementation of reliable and safe robotic systems in hazardous environments, such as underwater.

This paper presents UWSim-NET, an extension of the UWSim educational tool, that integrates both:
(1) the simulation of submarine robots, using the ROS platform (Robot Operating System),
(2) the simulation of underwater communication links through the use of the NS3 library (Network Simulator3).

On the one hand, ROS is the framework mostly used for robots programming and control, including underwater vehicles. On the other hand, the NS3 library offers a wide range of communication modules that allows simulating networks and comparing them to well-known TCP/IP protocols.

One of the applications of UWSim-NET is to introduce computer engineering and telecommunications students in the world of telerobotics in the underwater domain. For this, students will be able to use a C++ API, which will enable accessing the network devices of the UWSim-NET simulator, in order to not only simulate the robots in the 3D UWSim environment, but also to study the effect of sending and receiving communication packets to control these robots. In addition, thanks to the abstraction layer of the transmission devices, the programs implemented by the students are directly applicable to real devices (e.g. G500 and Bluerov robots), by just replacing UWSim-NET with a specific driver for the device.

According to these results, we can conclude that UWSim-Net permits the students to better understand the significance of the communications in the implementation of real robotic systems, specially when the intervention of an expert operator to supervise the operation is required.

Keywords:

Simulation, Educational Software, Communications, Underwater Robotics.