ABB IRB 6400 retrofitting

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27 Jan 2021 22:39 #196835 by Freak
Hi everybody!
First of all I love Linuxcnc, such a good open source project!

So I'm planning to retrofit an ABB IRB 6400 robotic arm, It's not my first time when comes to retrofitting, but never done with a robotic arm.

I have the old control, but it relies on corrupted recovery floppies and it's pretty old ('96)...

Two main things are different from what I'm used to:
  1. The robot has 6 revolvers read by a measurement board inside the robot self. Then it sends the position every half millisecond to the robot computer inside the cabinet. I have still to reverse engineer the protocol, I would like to reuse that board.

  2. The six axis servo pack is centralized i guess, there's an axis computer that compute the all 3 loops for every servo and moreover it should update the feed forward parameters dynamically based on the position of the robot (first time i hear about it and seems smart!)

As I mentioned I think i will keep the measure board since I have no idea where to find a replacement and i don't want to mess with analog stuff.

The first choice i whether or not keep the 6 3phases Hbridges, but i have to figured out their interface (i think they need 2 pwm each representing the sinusoidal control loop output of two phases, the third is calculated on the Hbridge driver, also the board send back the measured current but i don't know how).

I don't know if a pc can handle 6 current loops and I don't know how safe it is, it's a 2.5 ton robot... So my plan B is to replace also the drivers. I find interesting the mesa 8i20 and the odrive.

The mesa board is still a bit expensive if u consider i'll need at least 6 of them, and i don't know how much open source is the firmware.
The odrive seems not so much mature in terms of stability in an industrial environment, but looks promising!

I guess I'll try to fit an hall effect current sensor with an integrated HV igbt bridge on the odrive (also some galvanic isolation) and then I'll choose one of the many way to connect it to the pc.

What do u think? Any suggestion? :cheer:

Thank u for the attention!
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27 Jan 2021 22:43 #196838 by Clive S
Replied by Clive S on topic ABB IRB 6400 retrofitting
Well this will be an interesting read. :evil:

There are one or two people on hear that are into robots and ethercat
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27 Jan 2021 22:55 #196841 by tommylight
Welcome,
Skip the odrive, it just can not do that and it has a slow reaction time, if they did not fix it by now.
I would try to use the existing drives, even if removing the existing resolver card and using Mesa resolver cards (if they can be used, depends on resolvers).
Only if that does not work, changing the drives would become an option, although most probably it has the 600V drives/motors, so driving the motors with 220V drives should work with limited power/acceleration, 380V drives would be much better, still limited compared to originals.
Take some time to figure out how everything inside is set up, take notes of everything, might save a lot of time later on. Do this before removing anything, then plan what is to be removed and still do not remove anything, then start all over again.
The above statement is not a joke, i spend 2 full days on any machine just looking and tracing wires and stuff, drink a lot of coffee and check everything, over and over again.
And just in case, those things can crush a human in very disturbing ways, in a split second, without ever noticing the change in load.
The following user(s) said Thank You: RotarySMP

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27 Jan 2021 23:33 #196849 by Freak
Replied by Freak on topic ABB IRB 6400 retrofitting
Thank you tommylight!

yes I know what u say is very precious, I spend 2 weeks before retroffitting a Biesse Rover 7, just studing the manuals, electric diagram and so on, and I had some trouble anyway...

So if u tell me odrive haven't a good dynamic (maybe the 8Mhz curent loop is limiting?) I'll skip and try to use the original Hbridge.
Still i have to figure out where to perform the feedback loops, also the current one, since are all integrated in a complicated, undocumented computer board with volatile memory.

(i can barely move the arm when hanging on the end effector with brakes and motor off... can't think what would happend if it crash into humans...)
The following user(s) said Thank You: tommylight

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27 Jan 2021 23:40 #196852 by tommylight


So if u tell me odrive haven't a good dynamic (maybe the 8Mhz curent loop is limiting?)

Oh i never used them, but i know they are way to low on voltage and seen Marco Reps on youtube try to use them for cnc, did not work as the return to position after moving them by hand was very slow and sloppy. And he knows his stuff.

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28 Jan 2021 00:00 #196857 by Freak
Replied by Freak on topic ABB IRB 6400 retrofitting
Well I have one odrive board but never tried on an industrial servo, I have a small machine center home, maybe i'll try with one servo of that cnc (leadshine 400w 60v AC servo).
I have to understand if it's something achievable from proper parameters tuning and maybe some close look to the firmware, or just some limitation from the architecture (from a first look it seems doing what a common driver does, without an fpga). I heard the new version will be single driver, so with more computation power.
Next step test the odrive!

ps: the DC drive rectifier output 340V
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28 Jan 2021 01:22 #196871 by tommylight

ps: the DC drive rectifier output 340V

Nice, that is easier to work with.

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28 Jan 2021 15:19 - 28 Jan 2021 15:20 #196948 by Aciera
Replied by Aciera on topic ABB IRB 6400 retrofitting
Interesting! Any idea what you are going to do with it?

[edit]
I mean once you get the resolvers and motors working with LCNC.
Last edit: 28 Jan 2021 15:20 by Aciera.

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28 Jan 2021 18:18 #196981 by Freak
Replied by Freak on topic ABB IRB 6400 retrofitting
I would use it for some milling operations on wood, like big carbon fiber molds and so on, but i have to check the actual accuracy and the rigidity.
So yesterday night I had a look to the mesa shop and I found some good candidate boards for the new setup, withing few day I'll share the setup.
In the meanwhile do u have any suggestion?

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29 Jan 2021 00:08 #197005 by andypugh
Replied by andypugh on topic ABB IRB 6400 retrofitting
We need to know how you plan to drive the machine before we can suggest hardware.

Are you keeping the existing drives? What command method fo they accept?

At a guess the resolvers go to the drives. Do the drives output quadrature for position fedback?

It is easy to connect resolvers _only_ to LinuxCNC (7i49) but that only works if the excitation is from LinuxCNC too. You can't Tee-in to resolvers like you can in to encoders.

I have two machine tools using 8i20 and 7i49. But (as I have them) I would also be thinking of using the STMBL drive.

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