
Letting Robots Manipulate Cables - el_duderino
https://news.mit.edu/2020/letting-robots-manipulate-cables-0713
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beisner
Very cool. Good touch sensors are one of the biggest bottlenecks in
manipulation today - nearly everything commercially available is terrible and
extremely expensive.

I’ve only watched the video here, but I wonder how separable cable
manipulation is from the actual insertion task. At some point, there’s a
transition between the connector and the flexible cable that, for many kinds
of connectors, requires a transition in manipulation strategy. Think about how
you have to adjust your grip from the wire to the jack when you plug in a Cat6
cable.

I bring this up because the headphone jack example there isn’t really
demonstrative of this difficult modality transition dynamic.

Great work nevertheless!

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Groxx
This is using a camera looking at a perforated gel pad as a touch pressure +
force direction sensor.

The variety of uses for "point a camera at it" never ceases to amaze me. And
they're often cheap enough and reusable enough to be viable to individuals.

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gliese1337
Just think of how much stuff humans use "point eye at" for....

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waiseristy
And also just think at how well humans who lack this form of sensory input
still function

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gliese1337
If you want to make realistic estimates of the bounds of how well you can do
automation tasks without cameras, sure. But not really relevant for figuring
out how useful "point a camera at it" can be.

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ape4
I expected fishing wires thru crawl spaces and stuff. That's hard for humans.

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iandanforth
Related: PlayStation robotic assembly including cable manipulation

[https://asia.nikkei.com/Business/Companies/PlayStation-s-
sec...](https://asia.nikkei.com/Business/Companies/PlayStation-s-secret-
weapon-a-nearly-all-automated-factory)

As mentioned by other posters.

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cdaringe
I saw something recently about the PlayStation manufacturing plant, and I
recall that there were snippets of similar robots doing a lot of this complex
cable work. I'd be curious to know if this new work revolutionary or
evolutionary in contrast to what Sony's cable automation does right now?

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CobsterLock
I was wondering where I saw the cable robot last. I didn't know there were
already assembly robots that did that kind of stuff until now. I'm assuming
the major step here is handling a larger number of cables without re-
programming where the Sony factory was only optimized for that one cable in
that one step?

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Obsnold
Huh this reminds me of the TacTip from the Bristol Robotics Lab. I'm guessing
the sensor works in a pretty similar way.

Oh it seems there are some instructions on how to build one yourself:
[https://softroboticstoolkit.com/tactip](https://softroboticstoolkit.com/tactip)

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tylerwince
I never even thought about this being a problem until I watched the video.
It's amazing the types of things we have to build algorithms to handle that
our brain does naturally.

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stupidcar
Although brains cannot do it "out of the box". Most kids take years of
practice to achieve decent dexterity in even simple manipulation tasks. And
learning a new skill like guitar in adulthood makes it very clear that,
however sophisticated your capabilities in other areas, you have no innate
ability to perform complex physical tasks well without a long grind of
practice.

So yes, brains are incredible in what they can eventually achieve, and the
fact that the calculation involved becomes hidden from conscious awareness can
make it seem "effortless", but when you consider the sum of time and effort
spent practicing physical tasks over a typical human lifespan, it's really
anything but.

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xaedes
I actually need a robot for replugging USB cables. usb can be so buggy =(

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pmiller2
If it's pre-USB-C, I'd like to know your plan for solving the quantum
superposition issue USB connectors. You know, how every USB connector exists
in a state that's simultaneously correctly and incorrectly oriented? :P

Now that I think about it, I think the simplest way would be to slightly
modify the physical cable and the port so you could physically plug the cable
in, but it wouldn't work unless correctly oriented. I had always wondered why
they didn't just add another bit to the connector and cable that could allow
the controller to determine the cable's orientation, then appropriately
shuffle the incoming and outgoing bits so they go to the right places. Isn't
that roughly how USB-C solves the problem? I'm pretty ignorant when it comes
to most hardware matters. :/

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kevin_thibedeau
The wave function collapses on the third attempt.

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pmiller2
This looks cool, but it also looks like the only type of cables they're using
are copper wire cables.

I used to work at a hardware company that made and sold fiber optic switches
with hundreds of input and output ports. I worked on calibration and test
software for these things. Step zero to testing and/or calibrating one of
these beasts was to hook it up to a custom-built rig we built that ran the
software I worked on. This, of course, involved plugging in hundreds of fiber
optic cables.

Besides the difficulties mentioned in the article, fiber optic cables have an
additional property that makes them hard for robots to manipulate: inside the
plastic jacket, they're literally made of glass. So, you can very easily break
a cable, rendering it useless until repaired.

When we detected a likely broken cable, we had a neat method of finding the
exact location of the break. We'd take a very bright (10 mW) red laser and
shine it down one end of the cable, and see where the bright, red spot
appeared on the cable jacket. That spot would be where there was a lot of red
light leaking out of the cable, so, that would be where we cut and re-spliced
the cable.

The other difficulty is that for a robot to be practical in this use case, it
would need to be able to deal with the fact that there are hundreds of cables
around. Because they are fragile, and any significant bend in the cable can
introduce optical loss, you don't want to just willy-nilly go plugging cables
in and not worrying about how they lie.

Oh, and, probably the hardest thing for this type of robot to deal with would
be the fact that the cables were not all equivalent. Our rig had an infrared
light source on it that powered the whole shebang. Each light source had
something like 8 output ports that were very, very bright. I don't remember
exactly how much power they put out, but, in spite of not being coherent
sources, they were very bright on the IR test cards we used to check and see
if things were lit up. Each output port from the light source went into a
custom splitter we made that gave us hundreds of light rays that were each
just a few percent as bright as the original 8 output ports.

Each of these light rays traveled down a single cable, and we had the
capability to turn them on and off individually through some clever optics.
That meant we could literally light up one out of the several hundred cables,
send that light through the switch, and then measure where we expected those
photons to come out.

We needed that capability for several of our tests. This meant that the
individual cables were not interchangeable! They were, in fact, labeled, as
were the input ports on the switch, so we knew we could plug, say, light
source cable 57 into input port 57 on the switch, and then look to see where
the light would come out, and how bright it was.

Because they are optical cables, they need to be cleaned of dust before they
are plugged in, as well. The whole setup was in a room with HEPA air
filtration that approximated a clean room, so there was not much dust, but
there was certainly some. If a speck got on one of the connectors, it could
really screw up our optical loss measurements.

Because of these difficulties, even if a robot were available that could
handle a small number of copper wire cables, I suspect such a device could not
deal with fiber optic cable. As a result, our solution was to have interns do
the job of connecting and disconnecting the switches from the test/calibration
rigs, and avoid disconnecting them for as long as was practical. This is why
our rig was both a calibrator and a tester.

If you think about how long this would take to accomplish, consider that
cleaning the connector might take ~1 second, and plugging it in to the right
might also take ~1 second. Multiply that by 100, and you get 3 minutes per 100
cables. As I mentioned, these beastly machines had several hundred ports. And,
besides plugging the light sources into the switch inputs, we had to plug in
output cables that lead to an optical power meter on the rig. All in all,
around 750 cables would need to be cleaned and plugged in in order to hook the
switch up to the rig. 3 minutes / 100 cables * 750 cables is about 21 minutes,
which would be about the theoretical minimum amount of time it would take to
prep the switch for testing. In practice, it took anywhere between about 30
minutes to an hour. Unplugging the switch from the rig took about half that.
So, that's about 45-90 minutes involved in total, just to hook the switch up
to the machine we used for testing and calibration!

Unfortunately, it meant that we were employing people to do this for a large
portion of their day. We were near a university with a decent math department,
and, for some reason, the person who hired interns there really liked to
employ math majors. So, we had 2 or 3 college math majors we employed in large
part to plug cables in and unplug them when we were done.

I think it is fair to say that particular job will probably not be automated
away any time soon.

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jjk166
Assuming the fiber optic switches had their ports in the same position, why
not just make some tooling to hold the cables in position relative to
eachother and turn 600 cables into essentially one 600 pin cable? Or n 600/n
pin cables?

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pmiller2
Several reasons. Off the top of my head:

* This doesn't get you out of cleaning the connectors.

* You'd need very precise alignment to make this work, and I'm not sure our manufacturing tolerances were up to it.

* We would have needed 20 of whatever setup we used to do this. If you're talking in terms of robotics, that's probably the big deal breaker.

* Cables can still break, and getting them out of whatever holder you put them in could be an issue, not to mention even finding a break buried in 600 cables.

A lot of it really just comes down to "fiber optic cables are fussy and
fragile," really.

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jjk166
Clean the connectors while they are in their fixture. This opens up the
possibility of cleaning several simultaneously.

Making something more precise than a human hand is not particularly difficult.
If you don't have the manufacturing capability to do it, there are plenty of
job shops out there that can for a reasonable price.

If you can make the connections faster, you can run more in series, so you
probably don't need 20 sets. Even if you did, making copies of something is
cheap compared to the initial development. External hardware can be set up to
service multiple stations.

Many cables moving together in properly choreographed ways are going to be far
more robust than an intern fumbling around. If you're making the tooling such
that it is difficult to do routine maintenance, then it's a poor tool design.

In general, fussy and fragile things are the best for automation - you're
already bending over backwards to deal with it. It's when things are easy for
humans, with their amazing ability to adapt to circumstances and immense
contextual knowledge, that automation struggles to produce competitive
results.

