December 15, 2016
“A small swim for me, but a giant leap for undersea archaeology!” these could have been robot Ocean One’s comment if only he could talk.
In 2015, an extensive archaeological programme led by the French Ministry of Culture and the University of Montpellier set up a scientific collaboration with Khaled Nabil Salama
, Professor from CEMSE Division
and co-worker Professor Christian R. Voolstra, from the KAUST Red Sea Research Center, in partnership with Stanford University and Meka Robotics, in California, to develop Ocean One, an agile avatar that affords immediate and haptic-visual interaction – the process of recognizing objects through touch - in the ocean environment at depths greater than 50m.
Ocean One was developed on purpose for the archaeological study of La Lune wreck, one of the best-preserved wreck in the French sea.
In 1993, the wreck was discovered laying in 90 meters of water.
A previous program in 2012 was run to 3D-map the area and allow objects location recognition and planning on how to remove them.
During an expedition in 2016, Ocean One reached La Lune diving all the ways down to the 91m off to re-emerge with a vase, one of the La Lune’s treasures condemned to oblivion. Too far and inaccessible for humans, the two-decked vessel, once at the cutting edge of the French fleet, finally was accessible again by a man-made robotic diver.
Remotely Operated Vehicles (ROVs), able to dive in the marine environment exist since decades, but compared to Ocean One are like elephants in a glass-house. With a human-sized anatomy and a weight of less than 200 kg, equipped with augmented reality sensors, the KAUST-born avatar can handle autonomously both delicate artifacts and large assembly of structures for a huge variety of underwater tasks.
The futuristic vision of Salama and co-workers, in fact, is in Ocean One’s three-fingers hands. A sealed and oil-filled hand motor driver allows automatically adapting phalanges for a gentle straight-fingers pinch or a firm grasps. The interaction forces are sensed by a six-axis load cell at the wrist allowing to choose between low or high stiffness.
Fast response in stabilization, force control, and inertia reduction are also enabled by a pair of 7 –degree of freedom (DoF), electrically driven, torque-controlled arms, fitted with a series of electric actuators, coupled with navigation and posture controllers located in the lower part of the body and wirelessly communicating with the human control room via a relay station, and a pressure compensator.
The architecture is also designed to allow a human user to interact and intervene at any time. High-fidelity haptic feedback is provided by two sigma 7 devices, and the user is visually immersed in the scene through a pair of binocular stereo camera positioned at the robot’s eyes streaming to a passive 3D screen.
Ocean One success with La Lune’s expedition has opened the door to deep oceanic surveys and marks the beginning of new man-machine cooperation in extreme environments.
By Valentina De Vincenti