Living things are stupendously confusing, and when we make robots (even bio-inspired robots), we mainly just try and do the best we can to match the functionality of animals, rather than the details of their structure. One exception to this is hydraulic robots, which function on the same concept as spiders do, by pumping pressurized fluid around to move limbs. This is more of a side effect than actual bio-inspiration, though, as spiders still beat robots in that they use their blood as both a hydraulic fluid and to do everything else that blood does, like transporting nutrients and oxygen where it’s needed.
 
In a paper released in Nature this week, researchers from Cornell and the University of Pennsylvania are exhibiting a robotic fish that uses man made blood pumped through an artificial circulatory system to offer both hydraulic energy for muscles and a delivered source of electrical power. The system they came up with 'combines the functions of hydraulic force transmission, actuation and energy storage into a single integrated design that geometrically grows the strength density of the robot to enable operation for long durations,' which sounds bloody amazing, doesn’t it?
 
Conventional batteries may be more energy dense, but that Tesla also has to lug around motors and stuff if it wants to go anywhere. By using its blood to drive hydraulic actuators as well, this fish is far more streamlined. Inside the fish are two separate pumps, each one able to pump blood from a reservoir of sorts into (or out of) an actuator. Pumping blood from the dorsal spines into the pectoral fins pushes the fins outward from the body, and pumping blood from one end of the tail to the other and back again results in a swimming motion.
 
In total, the fish covers about 0.2 liter of blood, distributed throughout an artificial vascular system that was made on a pretty basic level to resemble the structure of a real heart. The rest of the fish is made of structural components that are somewhat like muscle and cartilage. It’s probably best to try not to draw too many parallels between this robot and an actual fish, though, and we may have already gone just slightly overboard on the whole “blood” thing. But the point is that combining actuation, force transmission, and energy storage has significant advantages for this particular robot. The researchers say that plenty of optimization is possible as well, which would lead to benefits in both performance and efficiency.



This article is originally posted on Tronserve.com