Kind: captions
Language: en
this tiny robot weighs less than a
tennis ball and can jump higher than
anything in the world
in the competitive world of jumping
robots the previous record was 3.7
meters enough to LEAP a single story
building this jumper can reach 31 meters
higher than a 10 story building
it could jump all the way from the
Statue of Liberty's feet up to eye level
for something to count as a jump it must
satisfy two criteria first motion must
be created by pushing off the ground so
a quadcopter doesn't count because it
pushes off the air and second no Mass
can be lost so Rockets constantly
ejecting burnt fuel are not jumping and
neither is an arrow launched from a bow
the bow would have to come with the
arrow for it to count as a jump
many animals jump from sand fleas to
grasshoppers to Kangaroos and they
launched their bodies into the air with
a single stroke of their muscles
the amount of energy delivered in that
single stroke determines the jump height
so if you want to jump higher you have
to maximize the strength of the muscle
the best Jumper in the animal kingdom is
the galago or bush baby
[Music]
and that's because thirty percent of
their entire muscle mass is dedicated to
Jumping this allows the squirrel-sized
primate to jump over two meters from a
standstill it has like you know very
small arms and upper body and it's just
like huge jumping legs it doesn't have
better muscles or anything it just has
more of them
there are some clever jumping toys
I used to play with these poppers as a
kid and when you deform a popper you
store energy in its deformed shape
effectively it becomes a spring and then
just like an animal in one stroke it
applies a large Force to the ground
launching itself into the air
all elastic jumpers follow the same
principle of storing energy in a spring
and releasing that energy in a single
stroke to jump
but none of the jumping toys we had
could compare to this tiny robot
of all the things that I have ever tried
to film this is the most challenging
because it's so small it accelerates
rapidly and travels a huge distance on
each jump
each takeoff happened faster than we
could even register
now jumping might sound like a niche
skill but engineered jumpers would be
perfect for exploring other worlds
particularly where the atmosphere is
thin or non-existent on the moon with 1
6 the gravity of Earth this robot would
be able to LEAP 125 meters high and half
a kilometer forward
Rovers May struggle with steep Cliffs
and deep craters but jumpers could hop
in and out fetching samples to bring
back to the Rover and you don't lose
much energy When jumping so if you could
store the kinetic energy back in the
spring on Landing the efficiency could
be near perfect
the team has already started to build an
entire fleet of jumping robots some of
them can write themselves after landing
so they can take off again right away
others are steerable they have three
adjustable legs that allow the jumper to
launch in any direction essentially what
we've done is we've added three
additional legs that don't store energy
but rather allow it to form a tripod
sort of that allows it to point a
direction and launch in that direction
but how does this jumping mechanism work
well the main structure consists of four
pieces of carbon fiber bound together by
elastic bands together they create a
spring that stores all the energy needed
for the jump
at the top of the robot is a small motor
a string wrapped around the axle is
connected to the bottom of the robot so
when the motor is turned on it winds up
the string compressing the robot and
this stores energy in the carbon fiber
and rubber bands after about a minute
and a half the structure reaches maximum
compression how do you know like when to
put it down basically once the bottom
there sticks Inward and it can stand up
right now it would roll over right then
you put it down got it so as soon as you
can and at this point a trigger releases
the latch that's holding the string on
the axle
so all the string unspools all at once
and the energy stored in the spring is
released
the jumper goes from a standstill to
over a hundred kilometers an hour in
only 9 milliseconds
[Music]
that gives an acceleration of over 300
G's
that would be enough to kill basically
any living creature
but how
higher than everything else nearly 10
times higher than the previous record
holder
well this jumper has three special
design features first the jumper is
incredibly light at just 30 grams it
achieves this weight by employing a tiny
motor and Battery Plus its entire
structure made of lightweight carbon
fiber and rubber doubles as the spring
per unit Mass natural latex rubber can
store more energy than nearly any other
elastic material seven thousand joules
per kilogram
foreign
the design of the spring makes it ideal
for its purpose initially they tried
using only rubber bands connected to
hinged aluminum rods but with this
design when compressing it the force
Rises to a peak and then decreases this
feels like it all of a sudden got a lot
easier to pull
another design with only carbon fiber
slats requires a lot of force to get
started and then it increases linearly
after that there is more and more more
and more Force required to do this the
ultimate design is a hybrid of these two
approaches the benefit being its Force
profile is almost flat over the entire
range of compression I feel like that
needs a lot of force and now it feels
pretty steady with the amount of force
that I need to apply therefore it
provides double the energy storage of a
typical spring where force is
proportional to displacement the
researchers argue this is the most
efficient spring ever made
sometimes a strangle snap it's not
always consistent that it releases when
it's supposed to
string cut it let me go let me go
restring it
I'll be right back you'd probably expect
that lighter would always be better with
a jumper especially if the added weight
is simply dead weight rather than
anything useful like a spring or a motor
so we're adding basically chunk of Steel
to our jumper and it's going to jump
higher and the key is that we're adding
it to the top you want your body the
part that's moving to weigh at least as
much as the foot when your body's
lighter it's basically this Collision
this energy transfer is very inefficient
and you don't jump very high
but the real secret to how this jumper
can achieve such Heights is through
something the researchers call work
multiplication unlike an animal which
can only jump using a single stroke of
its muscle an engineered jumper can
store up the energy from many strokes or
in this case many Revolutions of its
motor and that's how the motor can be so
small it doesn't have to deliver the
energy all at once it builds it up
gradually over a few minutes so the
trade-off is kind of like time for
energy exactly and this is possible
because there is a latch under tension
preventing the spring from unspooling
until the robot is fully compressed
interestingly biological organisms do
use latches for example the sand flea
which can jump incredibly high for its
body size it has a muscle that is
attached let's say right here is right
inside of the pivot point so as it
contracts that muscle the leg doesn't
extend right it's actually
closing it more but then it has a second
muscle that pulls it out it's going to
shift this muscle
ever so slightly
outside the Pivot Point that's wild so
there's these two muscles that are
working so here's your big Power muscle
here's your trigger muscle it's a torque
reversal mechanism and then all of a
sudden it shoots
but even though the biological world has
latches no organism has developed work
multiplication for a jump from
standstill at least not internally
spider monkeys have been observed
pulling back a branch hand over hand
using multiple muscle Strokes stored in
the bend of the branch to catapult
themselves forward
there's a spider that shoots out a silky
string which they pull back multiple
times in order to slingshot themselves
to another location
so it's like slingshotting itself yeah
these are all the slingshot spider
now I tried jumping in Moon boots to see
if they would help me go higher
and it certainly felt like they did but
Elliot pointed out that from a standing
start they don't actually help much
build it build it build it and then go
okay only if you jump a few times before
can you store up some of the previous
jumps energy in the elastic bands and
then that energy helps launch you higher
on the following jump
[Music]
for years engineered jumping was
developed to mimic biological jumping
but with work multiplication it gained
an advantage if you can generate a large
burst of energy simply by running a
motor for a long time the power of the
motor is no longer the limiting factor
the spring is so you can focus on making
the most powerful spring possible
this jumper has nearly maximized the
achievable height with this spring
assuming an infinitely light motor with
infinite time to wind up the highest
possible jump with this compression
spring is only around 19 percent higher
than what they've achieved if you want
to incorporate air resistance and play
with aerodynamics another way to send
the jumper higher is to make it 10 times
isometrically larger leading to a 15 to
20 percent higher jump so we're in kind
of an intermediate scale where we still
are getting hit by Air drag but it's not
as bad as the flea if we went 10 times
bigger we could actually avoid air dry
completely this works since if the
jumper is scaled up 10 times on all
sides the cross-sectional area increases
by a hundred which increases the drag
Force but the Jumper's mass increases by
a thousand so it has way more inertia
meaning the drag Force affects it less
the entire concept of work
multiplication could bring robots to the
next level
currently Motors and robots have to be
relatively small so they remain portable
but the simple principle of building up
the energy from multiple turns of a
motor over time would allow robots to
store and then release huge amounts of
energy and set some world records in the
process
getting this robot off the ground
required more than just engineering it
took a deep understanding of math and
physics and if you want to take your
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