RoboSavvy Forum

Robotis based industrial type robot model.

2012-09-10T16:13:30+01:00

Thank you Limor.
And yes. The aluminium link-pin made the difference. As predicted

Cheers
/Stig.

Statistics: Posted by sap1975 — Mon Sep 10, 2012 4:13 pm

Robotis based industrial type robot model.

2012-09-09T16:26:31+01:00

Hi Stig

Looks amazing. congratulations!

All those internal Lathe'd aluminum parts seem to make a difference in rigidity of the motion

Statistics: Posted by limor — Sun Sep 09, 2012 4:26 pm

Robotis based industrial type robot model.

2012-09-09T11:47:43+01:00

Time for an update.
We're getting there

phpBB [media]

The 5 DOF version is almost done. After some real life testing it turns out the gripper needs some work but all the other components are working as they should.

The "post" axis (the axis between the black part and the lower yellow part) is built using a belt and pulley system to allow the cables to run internally through a hollow shaft.
(that design took quite a lot of work and i think some 8 to 10 redesigns)

Servos... Except for the two servos attached at both ends of the arm which are AX-18's the rest of them are AX-12's. This is a lot easier to implement and program than the original mix of RX-64's, AX-12's and a single std. RC Servo that i used on the mock-up. Now obviously there's less power but for pure simplicity and cost it's a pretty good trade-off.

Some time in the future i'll post some pictures of the internal but for now this is it.

Cheers.
/Stig.

Statistics: Posted by sap1975 — Sun Sep 09, 2012 11:47 am

Pregress report

2012-05-19T14:08:47+01:00

So it's time for a status report.

Much has happened and i'm currently working on a slightly simpler 5DOF version instead of the overly complicated original 6DOF.

The "prototype" is now in a working state and as an all new feature it's in colour

phpBB [media]

/Stig.

Statistics: Posted by sap1975 — Sat May 19, 2012 2:08 pm

Robotis based industrial type robot model.

2011-09-11T18:02:58+01:00

Haven't got much time so its going to have to be the short answer.

Billy:
Thanks. that means a lot to me

atebay:
UP! 3dprinter. www.pp3dp.com

If you have any questions i'd be glad to answer them. Provided i can obviously.

Cheers
/Stig.

Statistics: Posted by sap1975 — Sun Sep 11, 2011 6:02 pm

Robotis based industrial type robot model.

2011-09-11T16:08:25+01:00

Out of interest what 3d printer are you using?

Statistics: Posted by ATebay — Sun Sep 11, 2011 4:08 pm

Robotis based industrial type robot model.

2011-09-10T06:28:04+01:00

Very cool.

Statistics: Posted by billyzelsnack — Sat Sep 10, 2011 6:28 am

Robotis based industrial type robot model.

2011-09-07T16:07:12+01:00

So... it's time for a long overdue update.

Getting the 3D printer has sped up things quite a lot. There where some initial teething problems with the printer but i'm just about getting things right now.

I have managed to get most of the structure designed and printed. i think there's about 30% - 35% left on mechanical. After that comes software.

Anyways. here's what it looks like now.
It's funny how all that work turned into something that looks a bit like a mechanical duck

Cheers
/Stig.

Statistics: Posted by sap1975 — Wed Sep 07, 2011 4:07 pm

Robotis based industrial type robot model.

2011-06-25T09:25:01+01:00

Hi again

I have had a look at the model and i can tell that this is going to take some time to finish it since virtually all the mechanical parts needs to be drawn up. I have most of the in my head but it takes time to put them on "paper".

However there should be enough information in the stuff that's ready to see where i'm going and it would leave some playroom for ingenuity.

Limor: I would like to take you up on your offer on a joint venture sort of thing. Any help would be much appreciated and i'd be happy to send the current state to you. Just tell me if you'd prefer STP or STL and where to put it These formats do take up some space and i don't think mail is going to cut it. Alternatively i could put them on my web site.

Let me know what you'd prefer.

Cheers
/Stig.

Statistics: Posted by sap1975 — Sat Jun 25, 2011 9:25 am

Robotis based industrial type robot model.

2011-06-24T14:21:38+01:00

The TX and RX are not independant on the RX64 and other RS485 servos. They are 4 wire because the RS485 signalling is differential and needs two wires. It is still bidirectional. The same signal which controls the direction of the TTL tristate buffers also controls the direction of the RS485 driver/receiver.

So the low level code should be very similar, though I never saw schematic of RX64 to check pinouts from processor. They do use an H bridge IC instead of the discrete FET used in AX, so there may be some rearrangement of the PWM outputs.

Statistics: Posted by i-Bot — Fri Jun 24, 2011 2:21 pm

Robotis based industrial type robot model.

2011-06-24T13:37:44+01:00

Hi, the firwmware works on AX12. it was tested on AX18 but there was some noise so the low level PWM frequency needs to be adjusted. no reason why it shouldnt work on rx64 except the RX/TX are independent so the firmware needs adaptation.

Statistics: Posted by limor — Fri Jun 24, 2011 1:37 pm

Robotis based industrial type robot model.

2011-06-22T18:03:35+01:00

Thanks Limor

Once again to the rescue That looks really interesting.

Having said that... have you guys made custom firmware for the RX-64's as well?
The only reason i ask is that the two main servo's are RX-64's

And yes i would be happy to share the CAD files.
I have to re-work them first though since i did a bit of re-designing and have ordered and received the bearings that needs to go in there.

Btw. WOW... what an offer.
I hope i get the time to work on it a bit during the weekend.

I was planning on 3D printing the "shells" and CNC milling the "Arm" from aluminium which is one of the two main causes of shaking if that makes any sense. The other one by the way is the base. that should cure itself once it's a closed structure.

I'll get back to you.

And thanks again.

Cheers
/Stig.

Statistics: Posted by sap1975 — Wed Jun 22, 2011 6:03 pm

Robotis based industrial type robot model.

2011-06-22T17:50:18+01:00

If you share your cad files we (RoboSavvy) also have a 3D printer and can maybe work together to improve the structure and get some good shakeless motions

Statistics: Posted by limor — Wed Jun 22, 2011 5:50 pm

Robotis based industrial type robot model.

2011-06-22T17:41:43+01:00

Hi Stig
It is possible to reduce the shaking and vibrations of that nice arm by gradually slowing down the servos as they reach their target position. We developed an alternative firmware for AX12 that allows much better speed control so that you can create nice motion curve profiles to accelerate and decelerate as as you reach target positions.
check out http://actuated.wordpress.com

Statistics: Posted by limor — Wed Jun 22, 2011 5:41 pm

Robotis based industrial type robot model.

2011-06-22T14:32:08+01:00

Thank you very much.

The project has been dormant for a while but i’m actually just about to pick it up again.

It turned out to be a bit expensive doing the structural components and covers but I just put in an order for a 3d printer and that should allow me to move on.

I’ll update the thread once I get around to it

Cheers
/Stig.

Statistics: Posted by sap1975 — Wed Jun 22, 2011 2:32 pm