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Robots Will Soon Be Powered By Artificial Hearts that Pump Pee

Scientist will imbue robots with an actuator that functions similarly to a human heart, except instead of circulating blood, it pumps urine through the machine.
Image via Sean McMenemy on Flickr.

Robots have hearts, too. Or rather, they should, according to a group of researchers based in Bristol, England. In search of a new kind of fuel pump to power robots, Peter Walters and four of his colleagues turned to biological principles, and found a creative solution they will present tomorrow in the journal Bioinspiration and Biomimetics.

Their solution? To endue the robots with an actuator that functions similarly to a human heart. Except instead of circulating blood through veins, it pumps—wait for it—pee through the machine.


Researchers were able to construct the actuator using a material made out of nickel and titanium (NiTi) called shape memory alloy. “The NiTi fibers used in the artificial heartbeat actuator function as artificial muscle, contracting when heated by an electric current,” Walters explained. “This contraction compresses the body of the actuator to effect its pumping action.”

Not only does the pump itself act like a piece of essential biology, it also works well with biological fluids, namely urine. Urine functions as an optimal source of fuel for bots—one whose efficacy has been proven before. “Urine has the advantage that it is a rich and plentiful source of energy,” Waters said. “And it would be easier to pump than waste biomass that is in the form of a more viscous fluid.”

The first robots that will receive the artificial heart are known as EcoBots, a category of machine that is considered energetically autonomous. According to Walters, energetically autonomous means that a robot “would be able to harvest the energy it needs to function from its environment, without relying on human intervention and conventional power sources.”

According to the paper, the focus on pee could allow an EcoBot to function as an “environmental sensing platform within an urban setting.” It could utilize the liquids left behind in urinals to power itself in an environment too polluted or otherwise dangerous for humankind.


Fittingly, parts of the device sort of resemble a toilet, as seen in the image below, which depicts the artificial heart pumping urine.

Image credit: Centre for Fine Print Research and Bristol Robotics Laboratory.

So far, the EcoBot models have relied primarily on fuel pumps powered by traditional electric motors. However, the artificial heart actuator built by Walters offers several benefits over the usual route.

First, it is a simpler option—a pumping mechanism based on artificial muscle fibers instead of mechanical parts. Second, the current systems can and do often suffer from blockages, but within the actuator, the offending particulates can settle to the bottom instead of impeding the device’s function. However, the actuator is still in its early stages and needs more development to surpass electric motors in terms of efficiency.

So will this artificial heart that pumps pee be a component of our future evil robot overlords? Walters hopes not. “It is difficult to predict or control the long-term application of any new technology," he said. "However, it is our hope that future energetically autonomous robots would be used for humane purposes, like environmental monitoring, and not harmful use.”