Ictineu AUV, is the result of a project started in 2006. During the summer of that year, the Defence Science and Technology Lab (DSTL), the Heriot-Watt University and the National Oceanographic Center of Southampton organized the first Student Autonomous Underwater Challenge-Europe (SAUC- E), an European wide competition for students to foster research and development in underwater technology. Ictineu AUV was originally conceived as an entry for the SAUC-E competition by a team of students collaborating with the Computer Vision and Robotics (VICOROB) group in the UdG. Although the competition determined many of the vehicle’s specifications, Ictineu was also designed keeping in mind its posterior use as experimental platform for various research projects in our laboratory.

Ictineu AUV was tailored around a typical open frame design. This configuration has been widely adopted by commercial ROVs because of its simplicity, toughness and reduced cost. Although the hydrodynamics of open frame vehicles is known to be less efficient than a closed hull type vehicles, they are suitable for applications not requiring movements at high velocities or traveling long distances. The robot chassis is made of Delrin, an engineering plastic material which is lightweight, durable and resistant to liquids. Another aspect of the design is the modular conception of its components which simplifies upgrading the vehicle and makes it easier to carry out maintenance tasks. Some of the modules (the thrusters and most of the sensors) are watertight and therefore, are mounted directly onto the vehicle chassis. On the other hand, two cylindric pressure vessels made of aluminum house the power and computer modules while a smaller one made of Delrin contains a Motion Reference Unit (MRU). Their end-caps are sealed with conventional O-ring closures while the electrical connections with other hulls or external sensors are made with plastic cable glands sealed with epoxy resin. Ictineu is propelled by six thrusters that allow it be fully actuated in Surge (movement along X axis), Sway (movement along Y axis), Heave (movement along Z axis) and Yaw (rotation around Z axis) achieving a maximum speeds of 3 knots. It is passively stable in both Pitch and Roll Degree of Freedom (DOF) as its meta-center is above the center of gravity. This stability is the result of an accurate distribution of the heavier elements at the lower part of the frame combined with the effect of technical foam placed in the top, which provides a slightly positive buoyancy to the vehicle.

One of the main objectives of the laboratory was to provide the underwater robot with a complete sensor suite. The robot includes a Tritech Miniking Mechanically Scanned Imaging Sonar (MSIS) designed for use in underwater ap- plications such as obstacle avoidance and target recognition. Also, the robot is equipped with a SonTek Argonaut Doppler Velocity Log (DVL) specially designed for applications which measure ocean currents, vehicle speed over ground and as an altimeter using its 3 acoustic beams. The particular spatial distribution chosen to place the acoustic sensors within the vehicle frame avoid dead zones, improving their overall performance. Moreover, Ictineu AUV has a compass which outputs the sensor heading (angle with respect to the magnetic North), a pressure sensor for water column pressure measurements and a Xsens MTi low cost miniature Attitude and Heading Reference System (AHRS) which provides a 3D orientation (attitude and heading), 3D rate of turn as well as 3D acceleration measurements. Finally, the robot is also equipped with two cameras. On one hand, a forward-looking color camera, mounted on the front of the vehicle and, on the other hand, a down looking Tritech Super SeaSpy color Charge Coupled Device (CCD) Underwater Camera, located in the lower part of the vehicle. The latter is mainly used to capture images of the seabed for research on image mosaicking while the former is intended for target detection and tracking, inspection of underwater structures and to provide visual feedback when operating the vehicle in ROV mode. Nowadays, Ictineu AUV is used as a research platform for different underwater inspection projects which include dams, harbors, shallow waters and cable/pipeline inspections.