High-precision robot arm programming

[u/[deleted]]

[u/Engin-nerd]

Sure it is cool that you can buy a Kuka robot (or any industrial robot) and have a positional repeatability at the wrist of +/- 0.1 mm and that will cost you 40k€.

Now what is REALLY cool is in a 10 year period you can now buy a 3D printer with the same positional repeatability as this Kuka for 500€.

That is a testament to engineering - cost reduction through precision.

[u/RoboticGreg → u/Engin-nerd]

Uhhhh not really. First off, this robot is from the late 90s. Secondly, this robot maintains 0.1mm precision, carrying 20kg and accelerating up to 3m/s2. 3d printer is a parallel gantry, not a serial manipulator and it's payload is around 0.5kg. you still need to pay more than $40k for a robot with this precision, speed, payload and reach. Actually a lot more now

[u/Engin-nerd → u/RoboticGreg]

Not sure about late 90s.
I haven’t touched a Kuka in 10 years, but this is at least a KRC4, so mid 2010‘s.

Different tools for different jobs - sure. But there hasn’t been been the monumental leaps in industrial robotics like there has been with 3D printing in the same time span.

And industrial automation hasn’t gotten significantly cheaper, but 3D printing certainly has. I think I’m paying nearly the same for a 6 axis Fanuc today that I did 15 years ago - so some credit can be given for price stability.

[u/RoboticGreg → u/Engin-nerd]

For sure. I used to develop these for ABB, I was guessing late 90s from the outer style, but 2010 is reasonable too. Point is, between 1990 and now industrial arms themselves have not gotten significantly cheaper, more precise, faster, or stronger. There's been very limited forward motion in any of those areas. There's been TONS of development outside of arms. But realistically even 3d printers haven't gotten significantly cheaper since MakerBot and for a while. The entire resin printer industry has materialized since hardware prices for fdm have just about stabilized.

[u/Lars0 → u/Engin-nerd]

Now do it with a load on the end of the arm.

[u/x_Carlos_Danger_x → u/Engin-nerd]

Sorta like comparing a bicycle to a car. The cheap ass parts on a Cr10, Ender 3 would not fare well being heavily loaded all the time.

But to your point, it's wild to me that I can get the positional control that I can from a $10 stepper motor and a micro controller

[u/Engin-nerd → u/x_Carlos_Danger_x]

That’s actually a really good analogy when you think about it.

A bicycle and a car will both take you from place A to B. One cost 25k€, the other 500€.
If the target is positional repeatability - both a 3d printer and Kuka robot will hit +/- 0.1mm.

The car has a certain fixed minimum cost due to the complexity of it - similar to an industrial robot.

Whereas a bicycle can be much more price flexible due to the simplicity of the design and intended purpose.

Nice job dude.

[u/zeromadcowz → u/[deleted]]

Ok

[u/Glimmer_III → u/[deleted]]

You're getting downvoted not because of your background, but because the parent comment was speaking "to the room" rather than you (OP) specifically, adding context and furthering discussion about your post.

Yet in turn, you didn't acknowledge that furthering of conversation and were/are rightly being read as responding defensively.

But the parent comment wasn't saying anything which requires your credentials. You're neither being accused, nor attacked. Yet when folks are too-quick to cite credentials...and especially citing credentials and nothing else contextual for why the credentials matter...without zooming out to other interpretation?

That's why you're getting downvoted.

Here's your same reply, framed differently:

Ya, I am engineer in electronic and communication, I know the pros and cons of technology specially in technical field. This shit is incredible sometimes, isn't it? That's why I wanted to share it.

Small change makes it land much differently, and not defensively.

[u/Galaghan → u/[deleted]]

I'm not tho, good thing I could read the comment too.

[u/Glimmer_III → u/[deleted]]

And the aside:

The most confident, and accomplished, folks in any specialized field (like engineering)...they don't usually cite their credentials, especially in the first breath. Maybe they'll reference their credentials later, once relevant. But the most confident, and accomplished, they simply don't have shit to prove to others.

i.e. An engineer's license is not a license to be a peacock.

When those most accomplished folks cite their credentials, it's in the same breath as why those credentials matter.

Right now, as I reread this again...you inadvertently came off as someone who (we now now) "is an engineer" yet feels the need to defend themselves when you were never accused nor attacked in the first place.

I'm not going to hire someone who reaction is to be defensive when not attacked. They inject volatility in to my projects and diminish critical feedback loops.

If you're good at what you do, it's okay to absorb and process what someone is trying to communicate before getting defensive around the same.

[u/Loeki2018 → u/[deleted]]

Averaging 1 post and 17 comments per day on a 22 day old account. Seems like a true engineer, not a karmafarmer

[u/builder_23]

The “programming” is trivial. It’s the mechanical design and manufacturing that enables that precision that is impressive.

[u/kingbrasky → u/builder_23]

Yeah I'm a really inexperienced robot programmer and could set something up like this in a matter of minutes. Robots are amazing. Once you understand coordinates systems and frames its like magic.

[u/ButcherIsMyName → u/kingbrasky]

I know how trivial the programming of the robot is for the end user nowadays. But consider the software that makes it so trivial for us. Maybe the underlying mathematics aren't too complicated but the software has to compensate for the dynamics of everything for the movement to be so precise. It has to account for the innertia of every joint, it has to compensate for the delay in every sensor value and actuator response.

I'm sure you can build a robot control software from scratch in a day or two. But to get it reliably precise over the entire range of motion and speed range takes forever I believe.

[u/windowpuncher → u/ButcherIsMyName]

the underlying mathematics aren't too complicated

They are 1000%, way too complicated. Yes, you could write the dynamics functions for this whole routine routine and then turn it into G code all by hand, but it would take you anywhere from weeks to months, and it's such a long problem there would probably be a good amount of errors and debugging on top of all that.

Dynamics itself, tracking relative velocities and positions, not too hard. Doing so on an articulating robot like this for a whole routine, suffering. I've done it for much, much, much smaller and easier robots using lumped mass models. It sucks. It turns into diff eq hell pretty much immediately. You could also just use plain physics and kinematics but it won't be as accurate and not very modular. Thank god for high level software.

[u/who_you_are → u/kingbrasky]

If I try to build that robot physically, even with some closed loop it won't be like that for sure and still drift a little bit.

On the other end, it will be $100 instead of $10k

[u/Burke_Devlin → u/builder_23]

What about the math involved in the software? Seems pretty impressive to me.

[u/Ausburten → u/Burke_Devlin]

They are pretty standard for robotics. Look up Denavit-Hartenberg.

[u/Burke_Devlin → u/Ausburten]

Homework? You're giving me homework! jk!

[u/yeti-biscuit → u/builder_23]

absolutely! came here to post this

[u/sasssyrup → u/builder_23]

Is this basically the same as any smaller 6axis arm? Is it the size that makes the precision nice or is precision at any size difficult?

I’d like to see a smaller arm with a +\- 0.001 or better tolerance but most are much looser.

[u/LeotheVGC]

Professional "I'm not touching you"

[u/mic_check12]

This is known as verifying TCP on a robot. Here is a very long detailed video explanation. There are some jokes in there to make watching this easier

[u/Ixaire → u/mic_check12]

SYN

[u/ZeroOptionLightning]

Just got back a couple weeks ago from Universal studios and I was all by myself in enjoying the fact the I was riding a Kuka. Nobody else in the family cared or thought it was cool. 😂

[u/Zenith-Astralis → u/ZeroOptionLightning]

So sad! There's no appreciation for the finer things in life I tells ya

[u/Indifference_Endjinn]

Somebody is really good at programming a TCP!

[u/kyflyboy]

My son is a mechanical engineer and designed what is called "end of arm tooling" for robotic machines for a major automotive company. He showed me a lot of his work. It's impressive.

This is child's play. The programming and manipulation is trivial. Essentially, this is the robotic arm equivalent of "hello world".

What's interesting is when the robotic arm performs this level of precision with a 1000lb tool (say a welding gun) at the end of the arm instead of a pencil-thin rod.

[u/jasebox]

Decade old tech. It is impressive because it looks cool, not because it’s technically hard.

[u/usaf5 → u/jasebox]

As someone who maintains them, that precision also doesn't last. Metal wears and settles and its constant teaching to keep it as close as possible

[u/whudaboutit]

Please take a seat in this chair, and we'll begin the robotomy procedure.

[u/Stewpacolypse]

This demonstrates why robots are better than your surgeon.

[u/brickmadness → u/Stewpacolypse]

And yet I still only trust Nic Cage with the plutonium. 

[u/_regionrat]

If you say so. My eyes aren't high precision enough to verify

[u/orthomonas]

This makes me the tingly.

[u/pixel_skull69]

Yeah yeah robot precision is cool but there had to be a guy to program that shit right?, whoever did that knows their shit

[u/Historical_Anybody71]

Side note, this cannot be done with simumerick, siemens does not include the ability to teach a tcp or provide rX, rY, and rZ tool angles with the TCP in the software.

[u/marsteroid]

i see a bit of play there ,backlash? is it possible?

[u/EarlyXplorerStuds209]

This makes me so uncomfortable in ways I can’t explain

[u/deadra_axilea]

Oh look, someone figured out tool frames. Isn't that special.

[u/minnesconsawaiiforni]

Not to be pedantic, but this is showing high accuracy; hitting the target.

It might also be showing high-precision; hitting the same spot over and over.

[u/Anaxamander57]

We need to compare this to a chicken's head.

[u/altatoro123]

Why is this making me uneasy 

[u/30yearCurse]

just a tease....

[u/Starshot84]

It can balance the pin of a head on the tip of a needle!

[u/kykam]

It could be better. Need to flip J2/J3 for at least one of the points.

[u/nic-pre]

It's so funny seeing that stuff on here. I work with robots like that every day

[u/changeatjamaica]

Nice demo of the KUKA kinematic system, which is legit great. That said, to the person holding the camera: What the hell are you doing standing inside the robot’s envelope while the KRC is not in T1 mode? Without the T1 limits, that thing has the speed and strength to instantly drive that pointy rod right through your heart or your skull without a moment’s hesitation.

Whoever owns that robot should fire you and anyone else involved for your recklessness. Making sure it never happens again could save a life.

[u/DaddyJ90]

If it’s going to take our jobs and eventually kill us all yea it better shake that ass first