A robot squid can match the energy efficiency of real animals, and could be useful for designing next-generation submarines.
True squid have small fins that they use for careful maneuvering, but when a large burst of speed is required they suck in and expel water to propel themselves. Researchers have been trying for a while to build a robot squid that mimics this jet-like behavior. Today a team led by Gabriel Weymouth at the University of Southampton, UK, has discovered a way to increase the efficiency of these robots, to inspire the submarine of the future.
The squid robot
Weymouth and his colleagues created an umbrella-like robot with eight 3D-printed plastic ribs covered by a rubber membrane. The robot squid flexes outwards to suck in water and contracts to expel it, providing the push needed to move.
The researchers experimented with operating the robot at a range of different opening and closing frequencies. They then compared its energy input and output to measure its efficiency.
The team found that firing pulses of water at the machine's natural resonance (the frequency at which the robot naturally tends to work) has seen efficiency achieved 100 times greater with respect to higher or lower speeds, corresponding to the
most efficient squid found in nature.
It is enormously better. We almost don't believe it. There will certainly be a weaknessGabriel Weymouth, University of Southampton
From the robot to the submarine of the future
By operating in this way, the Southampton-designed robot squid can take advantage of its resilient body. Snap shut and help boost his next push.
It's a bit like pushing someone on a swing, simply swinging them at the right time so that they go slightly higher each time.
Previous research has shown that many animals adopt a similar strategy to use natural resonances to increase their movement.
Weymouth hopes the project can be adapted to power the submarine of the future more efficiently and with less risk to wildlife.
The “squid version” submarine of the future would no longer have rigid propellers, but a soft locomotion system.
The team now plans to upgrade the robot with additional water thrusters to provide greater maneuverability, as the current version can only move in a straight line. Until then, pass me the line, a robot squid so they can have it fried.
Research references: Science Robotics, DOI: 10.1126/scirobotics.abd2971