Engineers develop self-charging turtle surveillance robot

Chuck Bednar for – Your Universe Online
As part of an ongoing attempt to develop underwater robots capable of thinking on their own, engineers from the National University of Singapore (NUS) have created a mechanical turtle capable of performing complicated tasks such as surveillance and energy harvesting.
In addition, the turtle robot is maneuverable, operates on a self-charge mode and doggedly performs the tasks assigned to it while also being able to adapt to obstacles that arise, they explained. Ultimately, they hope to develop a fleet of autonomous aquatic robots to perform tasks deemed too hazardous for humans, such as detecting underwater nuclear waste.
NUS associate professor S K Panda and colleagues from the university’s Electrical and Computer Engineering Department are working on the research and development of biomimetric machines that draw upon inspiration from nature to overcome technical issues. The team is currently finishing up work on the new robotic sea turtle, which they claim can dive deeper by using its front and hind limb gait movements, just like a real turtle would.
“Our turtle robot does not use a ballast system which is commonly used in underwater robots for diving or sinking functions,” Panda explained. “Without this ballast system, it is much smaller and lighter, enabling it to carry bigger payloads so that it can perform more complicated tasks such as surveillance, water quality monitoring in Singapore reservoir or energy harvesting for long endurance.”
“Being able to do a dynamic dive or sinking vertically means that it can also enter vertical tunnels or pipes in the seabed with very small diameters,” the professor added. “We can have a swarm of tiny turtles which communicate with each other and act collaboratively to perform their duties. With improved maneuverability they can go to tiny and narrow places like crevices where bigger vessels are unable to do so.”
Since it is smaller and lighter than other types of robots, it is also more energy efficient, the university explained. Since it is capable of recharging itself, it would need to return to home base less frequently, and the machine is also said to be agile enough to turn sharp corners with a small radius and without having to drastically reduce speed.
Doctoral student Abhra Roy Chowdhury, who has been working on the project for the last three years, explained that the team has also developed four other types of autonomous, underwater robots: a spherical one that mimics the structure of a puffer fish and uses a jet propulsion method similar to that of  squids and jellyfish, and three robotic fishes of different morphologies, all of which are said to be scalable, modular and able to avoid detection.
Chowdhury first developed a lifelike fish robot some three years ago after doing in-depth research on the maneuverability and energy efficient motion actual fish – specifically, the yellow-fin tuna and the freshwater largemouth bass. He used the information gathered through his observations to develop “a novel bio-inspired dynamics and behavior based control architecture for these biomimetic platforms,” the university explained.
Another member of the team developed a spherical robot that can be used to conduct oceanic surveys or a variety of inspections, including of a ship’s hull, a propeller shaft, or pipe and cable. This robot uses a “visual servoing” system that includes an on-board bottom facing camera module that is color-coded to extract the position information and then guide the robot.
As they move forward with their research, Panda explains that he and his colleagues “expect to invent robots capable of performing collaborative intervention missions three to five years down the road. What we plan to do in the near future is to develop robot fish with muscles which can undulate the way real fish do. For this, we need to develop special actuators.”
“We also aim to develop central pattern generators which will enable the fish to respond to external stimuli so that it can make crucial decisions to complete a critical mission,” he added.
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