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Mechanical Carp Takes Marine Robotics To New Depths

posted 23 Oct 2013, 09:03 by Mpelembe   [ updated 23 Oct 2013, 09:04 ]
The next generation of weapons for marine warfare may look and behave like fish. Scientists inSingapore are copying the natural movement of carp to develop a sea-going robot for use in stealth missions for the military, search and rescue operations or ocean floor research.

SINGAPORE (REUTERS) - Develeoped and built by researchers at the National University of Singapore (NUS), the robotic carp is a prototype they say is the first in the world that can be programmed to sink or float by itself. The robot fish sinks by allowing water into its body, and returns to the surface by releasing it.

Professor Xu Jianxin, researcher Ren Qinyuan and engineering student Fan Lupeng from the university's Engineering department, built the robot to mimic the movements of a live carp.

For three months they studied how carp move underwater using a camera to capture the fish's movements. They then converted the data into algorithms that could allow a machine to replicate the carp's muscle function.

The prototype measures one and a half metres in length, and weighs 10 kilograms. It can dive to a depth of 1.8 metres.

The researchers say their robot can be programmed to perform a wide range of functions from pipeline leakage detection and the laying of communication cables, to military missions requiring stealth.

Xu says the robot emulates biological motion patterns that require precise spatial and temporal precision. He says it is capable of greater range of movement - including a maximum turning angle of 85 degrees - than any other marine-based unmanned vehicle, using its fins like a real fish.

"First, it is energy efficient, it can swim for a long time, and second, it can operate well, it is flexible and can make different complicated moves in a small space. Third, it produces a low level of noise, it is quiet, not like the old submarines with the splashing sounds of the water, that even the enemies can hear," he said.

The team overcame the problem of waterproofing the fish body, the motor and the control box by using 1mm fine acrylic board for the fins and tails. Plastic foam attached to both sides of the robotic body maintain buoyancy and balance. An internal ballast system controls the diving mechanism, allowing the fish to dive sharply and to a precise depth.

The prototype is powered by batteries which can last up to an hour.

Increasing battery power is one area where the team is seeking improvement, but Ren Qinyuan says they are also refining the mechanics to work more efficiently under water.

"Especially when it reaches a certain depth, of 1.8m, or even 2m or lower, water pressure will be huge, which will impact its machinery as well as its electrical components. That's why going into deep depths will bring up numerous problems, which is why we need to research more into this to solve these problems," Ren said.

The researchers say the next step would be to increase the range of depth as well as reduce the overall size of their robots while adding sensors, cameras and GPS units, eventually turning their prototype into ocean-going eyes and ears for humans back on land