Scientists have
developed an octopus-like robot, which can zoom through water with ultra-fast
propulsion and acceleration never before seen in human-made underwater
vehicles. Most fast aquatic animals are sleek and slender to help them move
easily through the water but cephalopods, such as the octopus, are capable of
high-speed escapes by filling their bodies with water and then quickly
expelling it to dart away. Inspired by this, scientists from the University of
Southampton, Massachusetts Institute of Technology (MIT) and the Singapore-MIT
Alliance for Research and Technology built a deformable octopus-like robot with
a 3D printed skeleton with no moving parts and no energy storage device, other than
a thin elastic outer hull. The 30cm long self-propelling robot is inflated with
water and then rapidly deflates by shooting the water out through its base to
power its outstanding propulsion and acceleration, despite starting from a
non-streamlined shape.
As the rocket
contracts, it can achieve more than 2.6 times the thrust of a rigid rocket
doing the same manoeuvre. It works like blowing up a balloon and then releasing
it to fly around the room. However, the 3D printed polycarbonate skeleton
inside keeps the balloon tight and the final shape streamlined, while fins on
the back keep it going straight. The robot is capable of accelerating up to ten
body lengths in less than a second. In recent laboratory tests, the robot
accelerated a one kilogram payload up to 6mph in less than a second. This is
comparable to a mini-cooper carrying an additional 350kg of weight (bringing
the total weight of the car to 1,000kg) accelerating from a standstill to 60mph
in one second -- underwater. This performance is unprecedented in human-made
underwater vehicles. The researchers calculate that making the robot bigger
would improve its fast-starting performance, which could have applications in
the development of artificial underwater vehicles that can match the speed,
manoeuvrability and efficiency of their biological inspirations.
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