
Robots that can walk are now striding to market - pseudolus
https://www.economist.com/science-and-technology/2020/08/25/robots-that-can-walk-are-now-striding-to-market
======
Animats
The slow march to cost-effectiveness continues. But no killer app yet.

Much of this is a mechanical design problem. You need to be able to generate
large forces from a small package, but not all the time. Hydraulics can do it,
but then you need a big pump and power source, like the older Boston Dynamics
machines. Until recently, all-electric didn't have the power density. Now it
does. Which is why quadrotor drones work.

Small polyphase permanent magnet motors ("brushless DC") have taken over. The
controllers to drive them at variable speed are now cheap. No brushes, no
arcing, no magnet demagnetization. The remaining limit on motor power is
cooling.

It's too bad Schaft Robotics was liquidated. They were doing well on
humanoids. Then Google bought them, trashed them, and dumped the remains. They
were into small liquid-cooled motors. That's a way to get huge torques when
you need them.

Reduction gears are always a problem. If they're big enough not to snap gear
teeth on shock loads, they're too heavy. Better materials for toothed belts
have helped. Those have more space to absorb a shock load. Researchers like
harmonic drives, because they can put a big reduction in a small package, but
harmonic drives are especially vulnerable to broken gear teeth on overload.

Direct drive, without gears or belts, would be nice. The advantage of direct
drive is, as someone said a century ago in the context of electric
locomotives, "You cannot strip the teeth of a magnetic field." Washing machine
motors are often direct drive today. The electronics is cheaper and more
rugged than a gearbox. It's encouraging seeing that happen in a mass-market
product.

There's a lot of engineering like that which needs to be done to get mobile
robots down to the price of a non-luxury car.

~~~
tgflynn
Do you think there's any chance of direct drive generating enough torque for a
roughly human sized robotic arm with human like performance (say to lift a 20
kg load) ?

The last time I looked into this it didn't look like that much torque was
available in a small form factor. I found it rather surprising because larger
scale industrial robot arms appear to far exceed any biological arm in both
strength and speed.

~~~
Animats
In industrial robot arms, the problem is not having enough power to lift the
load. It's making the arm rigid enough that positioning the actuators will put
the end at the desired point. Most industrial robot arms are position-
controlled, usually rather blindly. Customers want repeatable motion to tight
tolerances, like a machine tool. The mechanics are overbuilt and under-loaded
to achieve that.

I've seen direct drive SCARA robots with a big pancake direct drive motor on
top. Those are used for vertical assembly, for designs where a straight-down
move puts the part in place. The arm moves in X and Y, then there's a vertical
piston-like actuator that moves in Z, and a rotation axis around Z.

~~~
candiodari
There is lots of research pointing out that the problem may in fact be trying
to do that at all. A significant issue with this is that humans can't do
precision positioning of limbs in free space, yet can carry out all the tasks
people want to use these robots for.

When you see surgeons, who have loads of theory about precision movements you
will quickly find that they rely on feedback rather precision for their
movements. For example, they cut along the "linea alba", not by knowing where
it is and positioning the knife exactly, but by simply slicing down starting
at a good enough position, knowing the knife will follow the linea alba
because it's attracted to it. Which is a fancy way of saying that it's a force
feedback problem, not a positioning problem.

~~~
tgflynn
Humans can be very precise when they need to be (ever try repairing any modern
electronics ?) but yes they do that closed loop using both visual and tactile
feedback.

~~~
candiodari
They can't really. If I were to tell you to position your arm -5cm, 0cm, 0cm
relative to your nose, I'd be impressed if you got the three numbers to match
while passing through them. Holding a plate at that position for a minute
while I put 1kg worth of objects on it is out of your capabilities. You use an
object to move precisely around it. Not just visual feedback but (when I
repair electronics I) use the electronics to keep most of my muscles in place,
while only moving one or two, and not very precisely at that, I always need to
correct things afterwards. Stopping is done using force feedback (hitting
something), in case of soldering even smell comes into the picture.

I can hit a 2mm square target reliably with my an instrument held by my
fingers (and my hand resting or held in place) and, say, a 2cm target with my
hand. I get that I'm probably not surgeon material, but let's say they can
double or triple that accuracy. 10x is out of range of any human without
robotic help.

Robots are expected to do that with three numbers behind the decimal point and
to keep that position, while carrying their load (varies from 200gr to 20ton).
There is no way a human can do that, not even with 200gr, to an accuracy of a
centimeter. And even trying will be so stressful you wouldn't be able to hold
it for even a minute. A robot can hold it for 10 years.

------
samcheng
Youtuber Marques Brownlee had a cool video on Spot last week.

[https://www.youtube.com/watch?v=s6_azdBnAlU](https://www.youtube.com/watch?v=s6_azdBnAlU)

His takeaway was that the big use cases currently are around LIDAR and
mapping, e.g. tracking construction progress, in irregular / uneven terrain.

I'm less convinced that walking robots are useful for some of the use cases
described in the Economist article, like moving boxes in a warehouse. After
all, warehouses are generally built to facilitate wheeled vehicles (forklifts)
already...

~~~
clairity
yes, it's been common knowledge in biomechanics that wheeled vehicles win on
flat surfaces, hands down (ha). legs are good for the 99.9% of earth's land
that isn't nearly as predictable. the general utility of accessing that 99.9%
is relatively dispersed though (and hard to build a business on).

~~~
Robotbeat
Simply using big wheels or tracks work for non-flat surfaces, too, and are
cheaper & more efficient (especially the wheels).

Legs allow you to climb, ie a ladder, very steep stairs ( more than 45
degrees), a tree, or an extremely steep rough slope (think: mountain).

A tracked vehicle or large-wheeled vehicle can go almost anywhere a legged
robot can go with a large efficiency and cost advantage.

However, you can run into space constraints. Bipedal robots are good for
navigating human-scale environments while still having a tall and stable
robot.

But generally, tracks or big wheels are way cheaper and more efficient and can
do the same thing.

~~~
clairity
sure, bigger wheels and tracks can get you some greater percentage of
navigable land, but nowhere near 100%. most terrestrial animals uses legs and
not wheels for a reason (and it's not because it's not evolutionarily
possible).

but yes, bigger wheels and tracks probably cover a greater percentage of the
commercially viable landscape.

~~~
Robotbeat
It is close to evolutionarily impossible to do a wheel and axle biologically.
If the whole animal rolls, sure, but not a full wheel and axle
(macroscopically). That is probably the main reason we see zero macroscopic
animals with that configuration.

~~~
clairity
biology on an evolutionary timescale is exceedingly clever, more ingenious
than us humans. you don't need an axle, just something roundish (eyeballs or
even pearls, for example).

~~~
thombat
The organism will need something like a fluid rotary union so the nervous and
circulatory system can reach the rotating part, or that part will be limited
to very low metabolic levels (basically diffusion). That will certainly be
ingenious.

~~~
clairity
certainly, but biology is amazing. our muscles are basically chemical ratchets
interconnected throughout a mosaic of levers (ignoring the complex control and
feedback mechanisms, as well as the energy and waste systems, for a moment).

also, your point is why i mentioned pearls--not all tissue needs to be
activated or enervated similarly, or at all.

we should have no doubt that biology would find a way given enough time.

~~~
Robotbeat
It has found a way! Through engineering. We invented wheels, and we’re a
result of evolution. Dung beetles have engineered something similar, although
no axle (yet).

------
jariel
Please make me some AI that can clean my toilet, do my laundry and make me a
ham sandwich. This will be the revolution.

~~~
ipnon
This is disparagingly referred to as momtech. Young silicon valley transplants
try to replace the role of their parents with technology. They want to avoid
cooking and cleaning so they can code all the time. "If only a robot could do
my dishes for me!"

It's the epitome of fitting a solution to a problem. Cooking and cleaning are
simple tasks that any able bodied person can do themselves. There is no
shortage of able bodied people in the world.

~~~
tlb
A good rule of thumb when dismissing some new technology is to ask, "what
previous technologies would I have dismissed for the same reasons?" And if
those technologies became successful, try to learn from the mistake.

In this case, clothes washing machines and vacuum cleaners seem to fit your
thesis.

~~~
function_seven
And the Roomba fits this rule of thumb again by replacing the vacuum cleaner
(which replaced, what, taking rugs outside and beating them with sticks?)

On a tangent: How was wall-to-wall carpeting cleaned before the invention of
the Hoover? Did it just not exist before then? Or it just collected dirt until
it was replaced?

~~~
melling
[https://en.m.wikipedia.org/wiki/Carpet_sweeper](https://en.m.wikipedia.org/wiki/Carpet_sweeper)

~~~
function_seven
Oof. We had one of these growing up, so I know about them. Just didn't
remember it when I replied.

Still useful for collecting crumbs around restaurant tables.

------
elihu
Is it possible to make one of these robots cheaply? It seems like the cost of
actuators (which you might need dozens of) and to a lesser extent sensors
would make this cost-prohibitive for most uses.

For instance, if you were replacing a human salary, it might make sense to
purchase a hundred-thousand-dollar robot, but if you just want something to
pull weeds in your yard once in awhile, it might be hard to justify spending
more than a couple thousand. If the parts alone cost tens of thousands, then
that's a pretty big economic limitation on how the technology gets used.

------
sradman
Boston Dynamic's four-legged Spot [1] and bipedal Atlas [2]. Agility Robotic's
Digit [3]. It looks like robotic actuators are about to hit an innovation
wave.

[1] [https://www.bostondynamics.com/spot](https://www.bostondynamics.com/spot)

[2]
[https://www.bostondynamics.com/atlas](https://www.bostondynamics.com/atlas)

[3] [https://www.agilityrobotics.com/meet-
digit](https://www.agilityrobotics.com/meet-digit)

~~~
Robotbeat
Quasi-direct-drive actuators (BLDC motors with position Feedback and a modest,
5:1 or 10:1 gear ratio) are what you’re thinking of for Spot and similar. For
Atlas, you kind of need the specific force and low speed specific power than
hydraulics give you. That’s what Boston Dynamics uses for those larger dynamic
robots (Atlas, Big Dog, etc). (Hydraulics are under-rated! They can be
electrically pumped, so they need not be super loud.)

------
banmeagaindan2
I don't believe robots will have human level walking skills in our lifetime.
This is something that looked easy for 70 years. Hans Moravec described why it
was harder than it looked. It is possible to look impressive by pouring in
more brains and money but unless you have a general purpose breakthrough it
can not be useful and economical.

AI vs AGI is well understood in cognitive tasks but tasks that require motion
would also require a parallel breakthrough.

~~~
simonebrunozzi
> I don't believe robots will have human level walking skills in our lifetime.

If "lifetime" can be considered to be the next 50 years, I absolutely disagree
with you. I'd even venture to say that we will see robots with human level
walking skills within the next 15-20 years, at most.

~~~
banmeagaindan2
I assume you are the famous simone of youtube robot fame. I just speak as
outsider looking in. I like robots. It would emancipate society to a new level
of existence. I have trouble believing they are real - and have dark ideas
about what robots really mean in our society - that they might be a symbol of
something like a political belief in a sort of utopia in much the same way the
Soviet and Fascist investments in science were not value neutral.

I remember looking at some original robots developed around midcentury in
England. They were inexpensive and very bad but did function basic functions.

I look at the Boston Dynamics robots and see these are very expensive robots
performing more natural movements.

Let us suppose the BD and similar teams are at the half way point.

To get human level performance at this rate of change means trillions of
dollars. This robot would impress us - just as the original English robots and
BD robots do. The French Empire invented expensive and difficult to create
toys and no robot revolution started. I don't see anything continuous between
the idea of a robot and the idea of machine automation - I think that is too
much generosity. I know people want to give it because the field is very
difficult - but this is not being honest.

The ideal of the robot - people have different ideas about this - but the
ideal for me is that there is an economical and effective alternative to human
level physical articulation. I'm sure you have more advanced definitions -
this is just the basic benchmark. It should be plausible for a robot to sew a
thread or squeegee a window with grace.

It is not just human level articulation - it's also generalist application.

General purpose machine articulation looks like a high bar to the point it is
difficult to imagine what the world would look like were we to be successful.

------
k__
are they a suitable alternative for wheelchairs?

Because of stairs, etc.

~~~
lowdose
This is an unexpected original application. Do you think people in a
wheelchair would like to upgrade to a robot?

~~~
k__
Don't know.

But maybe it would

1\. allow them to stand

2\. allow them to use stairs

~~~
jon_richards
That’s starting to sound like an exoskeleton

~~~
ufmace
If we're going in that direction, might as well get rid of those useless bio
legs and replace them with robot legs

~~~
k__
I'd assume some people aren't fond of surgery.

~~~
tgflynn
I think a bigger problem is that there isn't really a good safe way to
directly interface a human limb to a mechanical one. Conventional prostheses
distribute weight over tissues that didn't evolve to carry those loads and are
therefore much less comfortable than a natural leg.

~~~
ufmace
Mmm yeah, I suppose you'd have to figure out a way to connect up to bones for
structural support and to connect actuators to. But hey as long as we're
dreaming big, why not?

~~~
k__
I'm not dreaming big.

I just asked if we could strap people to these things to let them climb
stairs, lol

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DenisM
So how about some Mountain-Boting[#]? Riding a BigDog" on the mountain bike
trails at crazy-stupid speeds.

[#] Mountain-Boting is now a word

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neonate
[https://archive.is/D0rEJ](https://archive.is/D0rEJ)

