Why Scientists are Giving Robots Human Muscles

Why Scientists are Giving Robots Human Muscles


[♪ INTRO] As robotics has become more advanced,
we’re starting to see more robots that look and move just like humans. But there’s still some room for improvement,
like to robotic faces. It’s a complicated thing, the face. We’re still working on getting out of that Uncanny Valley, there. And one way we might
close that gap is to replace clunky robotic parts with human ones. While this might sound like Bicentennial Man,
human-robot hybrids or biohybrid robotics isn’t a sci-fi dream,
it’s a real field that already exists. And it’s not just a way to
make more life-like robots. By mimicking our bodies better,
biohybrid robots might help scientists learn more
about how we move, why we’re built the way we are, and how
to fix all these moving parts
when something goes wrong. Just like a human body,
a robot generally needs a skeleton, and ways to move that skeleton. These include motors and actuators, which can deliver rotational or linear forces
to the joints of the skeleton. In biohybrid robots, that movement
comes from live muscle tissue. Of course, scientists aren’t just taking entire muscles from humans
and throwing them on a robot. At least if they are, they’re not telling us. You don’t know what they’re doing
in that weird volcano lair. But, the legitimate scientists,
they grow their own muscles. This happens in a lab by culturing myoblasts, embryonic cells with the unique ability to differentiate into different muscle cells
in a process called myogenesis. To make muscles grow how they want, the scientists create a scaffold
in the form of a hydrogel, a special water-based gel that’s great at
absorbing and retaining cells. Inside the hydrogel, the cells form into muscle fibers, long strands of muscle cells that all pull
together in the same direction. By altering the shape of the hydrogel, the alignment of the muscle fibers
can be tweaked and adjusted, giving scientists control over
the direction they pull in. And once these fibers are formed,
a tiny electric shock is all it takes to make them contract. They are then ready to be connected to
the joints of a robotic skeleton, and voila! A biohybrid robot is born, or built, I guess. We don’t have whole human replicates running
around, though. Not yet, anyway. Scientists at the University of Tokyo just
managed to get small muscle pairs working in early 2018. That’s because there are a number of limitations that need to be overcome before biohybrid
robots really take off. These lab-grown muscles don’t have any way
to repair themselves, so they only last a few days to a week. In your body, muscles receive spare parts
via your blood. But biohybrid robots don’t have that fluid
exchange system, so once the tissue wears down, that’s it. And this breakdown is accelerated by the
friction generated when the muscles move. So, your muscles are surrounded
by epimysia and fascia, connective tissues which
separate individual muscles and help them glide smoothly past each other. So to last longer, biohybrid robots need some kind of biocompatible lubricant
to reduce friction, like bio-WD40. Also, the electrical stimulation part
could use some work. While it does get the job done,
it’s difficult to control precisely how strongly the muscle contracts, especially
for sustained contractions. So fine motor movements
aren’t really possible yet. The electricity also contributes to wear and tear. The muscles have to stay wet, so using electricity
inevitably causes some of that water to separate into hydrogen and oxygen gas,
a process called electrolysis. These gas bubbles, in turn,
further damage the muscles. One possible way to get around
that is to grow motor neurons in the muscle tissue and let them
command the muscles instead. Which seems a little too close to a Westworld
host for my comfort. But there are some good reasons to continue perfecting these biohybrid robots, even if
they seem pretty creepy. One big advantage of using
real muscles is that they are flexible. And the idea of using soft, flexible moving
parts is the driving force behind the field of Soft
Robotics. These robots use things like cables and inflatable bladders to move
instead of metallic motors. And their flexibility allows them
to adapt better to new tasks. Biohybrid robots could lead to better soft robots, including ones that would be safe
to use on or even in our bodies, since they won’t have as many sharp bits
or cell-harming chemicals in them. But what’s really exciting to scientists
is that biohybrid robots can move like us. That means they can help us understand
why we move the way we do, how our brains control our bodies,
and how to fix things if they go wrong. The human body is an incredibly complex machine. Hundreds of muscles are responsible
for moving the joints in our limbs that allow us to work and play and do things like click that button below to subscribe to SciShow. Yep. Several muscles can be
responsible for a single movement, and a single muscle can contribute
to several different movements. And that means if someone
develops a motor impairment, it can be difficult to understand exactly
what’s going on. For example, people recovering from a stroke sometimes experience hemiparesis, or weakness
on one side of the body. Others may have muscle synergies, where activating one set of muscles results in the involuntary
activation of another. Both conditions may be a result of missing
or mixed communication from the brain, changes to the muscles themselves, or some
combination of the two. Having a biohybrid robot that mimics
a human arm might help scientists better understand how these
conditions arise and, more importantly, how therapists can best work
with patients to help them recover. Basically, we have to build ourselves from scratch
to fully understand these marvelous bodies. Which I’m fine with, so long as we stop
short of that full-on Westworld scenario, where I’m not sure whether Caitlin’s real or not. Also I wouldn’t mind if we made some
progress on those faces. It’s not good. Thanks for watching this episode of SciShow! If you want to continue learning
about how humans work, stick around by clicking on that subscribe
button, using all your muscles! And if you want to learn more
about how your muscles work and how to make them, you can
check out our episode on proteins. [♪ OUTRO]