collapse

Author Topic: robotic drawing arm  (Read 6204 times)

PharmerEd

  • Member
  • ****
  • P
  • Posts: 2
robotic drawing arm
« on: October 14, 2016, 06:06:00 AM »
I put together a 6 dof robotic arm. I would like to program it to draw pictures. I have an Arduino Mega and want to set it up using the reprap 3d printer Marlin software. I would use inkscape to convert drawings in 2 dimensions. I would skip the z-axis function, printing the first layer of a model only.  I want to translate the x and y axis motor signals and convert it to 3 motor outputs each.  For example, moving the pen up the y axis involves 1 motor on a prusa i3 printer. But using the arm, the pen would arc up away from the plane of the paper.  I need to translate the y-axis motor output to move the "elbow" of the arm to move the y-axis up the plane of the paper while at the same time, moving the "shoulder" of the arm down to keep the pen from arcing up away from the plane of the paper and moving the "wrist" of the arm to keep the pen perpendicular. The same goes for the x-axis. 
I have no coding experience but have changed or added g-codes to models sliced in repetier host.
The ideal set-up would be to add funtions to Marlin (is that possible?) to convert one output into 3 as explained above.  Another option would be to put the .stl file through a document editor, use find and replace to change and add lines and create a new .stl file.  I think I could use the multi-extruder function of Marlin to control the extra motors?  A third option, I am thinking of, would be to use a second Arduino to take the x and y output signals from the Mega board and convert them and divert them to the additional motors.
Any ideas?
Thanks

Killer Angel

  • Member
  • *
  • Posts: 62
Re: robotic drawing arm
« Reply #1 on: October 14, 2016, 07:06:20 AM »
Killer Angel [:|]

bdk6

  • Guest
Re: robotic drawing arm
« Reply #2 on: October 14, 2016, 11:10:41 AM »
There are a LOT of ways to build a 6 dof arm.  You haven't given any details on how yours is constructed.  How you convert from the given Cartesian (x,y,z) coordinates to whatever coordinates your arm needs will be different depending on how your arm is built.  Please give a LOT more details.  Detailed drawings would be good.

You are going to need quite a bit of trigonometry to accomplish this.  You aren't real clear on exactly what you want to do.  Do you want to write a program that converts the stl file automatically?  Or are you wanting to find some other way to do it?  Please elaborate.

Keep in mind you only need two, or perhaps three, dof to reach any place on a 2d plane(drawing.)  What are you going to do about the other 4 axes?  do you want to just fix them in place?

And, what kind of motors and controllers are you using to move each dof?

mogul

  • Hot glue gunslinger
  • Member
  • *
  • Posts: 151
  • This is a good day!
Re: robotic drawing arm
« Reply #3 on: October 14, 2016, 11:28:47 AM »
I have no coding experience ...  add funtions to Marlin (is that possible?)

As a programmer I see Marlin as a quite messy bowl of spaghetti left in the sun. Sticky, badly entangled and rot is starting to show.

I don't see Marlin as a friendly coding environment where it is easy to add features. at least not ti the completely un-experienced programmer.

On the other hand. Marlin might already have some of the features you need, it has support for several different mechanics, maybe yours too. Configuring Marlin is a bit different from actually hacking code in there.

Please make us a post in a relevant section, show us what you have so far and sketch where you see the project go. Realize that it take time and effort to explain your setup clear and detailed.

Then, go play with the machine, learn how it work and what it takes to get it to behave. Ask questions and we will have a common ground of understanding to base our answers on.


/moglue

Impala

  • Member
  • *
  • Posts: 189
  • Henbane Wellington Soufflage
Re: robotic drawing arm
« Reply #4 on: October 14, 2016, 03:39:45 PM »
I think you need to write up a specifically defined list of what you have and everything you want to do. There's a lot of details not defined in your help request.

If your arm uses stepper motors, then this should be a pretty easy project as most of the regular hobby cnc equipment can do what you are seeking without you being a programmer.
Others have used it to make cnc drawing hexapod walking robots as linux cnc has that ability as part of the regular free download.
(a hexapod is the same as your arm, just a different shape configuration in basic terms)

PharmerEd

  • Member
  • ****
  • P
  • Posts: 2
Re: robotic drawing arm
« Reply #5 on: October 15, 2016, 01:28:18 PM »
Thank you for all the quick replies.  I picked up a kit last year and finally got around to putting it together.  It uses "high torque" servos, not stepper motors.
    6 degrees of freedom robot arm / base metal disc / intelligent 3D rotation manipulator / Education Robot  +mechanical claw +6PCS high torque servos  (metal gear and with a full set of accessories)+ large metal base,Free shipping
Product Description:

    Size:46cm*10cm
    The rotation Angle of 180 degrees
    The radius of gyration: 355 mm
    A complete set of height: 460 mm  (holder closed)
    Clamping the front of the biggest opening: 55 mm
    Gripping the widest distance: 98 mm 
The data of high torque servos:
    Dimension : 40.8mm x 20mm x 38mm
    Weight : 55g
    Package weight: 74g
    Operating Speed: 0.17sec / 60  degrees (4.8V)
    Operating Speed: 0.13sec / 60  degrees (6.0V)
    Operation Voltage : 4.8 - 7.2Volts
     Torque:13KG-CM(4.8V);15KG-CM(6.0V)!
    Gear Type: All Metal Gears
I would position the arm at the zero coordinates of the drawing plane. 
I have seen CNC style drawing and painting robots but with only 2 motors controlling the x and y axis. I would use as many of the "joints"as needed and ignore the rest.
I have a Prusa I3 printer and can print a new arm but I would like to make use of the one I picked up.
The purpose of this project would be to mimic the action of a polar drawbot  or watercolorbot, but using the arm-style robot. 
I was hoping I could just convert the signals going to the x axis motor and the signals going to the y axis motor and simply convert them to control the robotic arm motors.  I can see there is a lot of trigonometry involved.  The Dobot seems to do what I was hoping.  I am looking into that this weekend.
Thanks

bdk6

  • Guest
Re: robotic drawing arm
« Reply #6 on: October 15, 2016, 02:43:43 PM »
Still not a lot to go on.  At least a link to the kit would be helpful.
Generating the signals for servos is plenty easy using an arduino.  The problem isn't making the signals, it's deciding what signals to send.  That's where the math and programming come in.  But the calculations will depend on the EXACT configuration of the arm, which you haven't provided.  To the best of my knowledge ( I don't use Arduinos much) all actual Arduinos of the last few years can control six servos natively. Also to the best of my knowledge ( I don't have a 3d printer) no 3d printer firmware is written to control servos.

But, again, the problem is NOT controlling the servos.  Telling them to move to any particular angle is very easy with an Arduino.  The problem is deciding which angle they should move to.    Each coordinate has to be converted from Cartesian (x,y) coordinates to whatever coordinate system the arm uses.  The coordinate system of the arm is unique to its EXACT configuration. 

Impala

  • Member
  • *
  • Posts: 189
  • Henbane Wellington Soufflage
Re: robotic drawing arm
« Reply #7 on: October 15, 2016, 06:53:22 PM »
I did a quick search on the concept by opening the first 2 links from googoo. I think this is a do-able project. But I DO NOT think its a project for a guy who can't program. If you look at these 2 pages, it should be pretty easy to write an in-between to convert the normal PWM stepper driver side of the output and change it to PPM a, servo for output. A little serial network between a pc and arduino(s) should easily be able to do this. You might need a buffer and a slow COM rate, as I believe the mechanical bits of this would create this requirement. (servo's are real slow) But I believe it could be done by those with some Ardy experience.

Another interesting aspect of this project is in the concept of reading in a PWM from a stepper driver to be converted to PPM output. It would be a dirty process which would make most programmers AND electronics guys scoff at the backwards logic in doing it. But the return you would get is that most the cnc hardware/software that's out there could be used to directly drive robots. I believe the benefits would be interesting for the effort. Definitely not a project for me!

https://forum.arduino.cc/index.php?topic=256814.0

https://www.marginallyclever.com/2013/08/how-to-build-an-2-axis-arduino-cnc-gcode-interpreter/

jinx

  • calling from free Europe
  • Sr. Member
  • *****
  • Posts: 469
Re: robotic drawing arm
« Reply #8 on: October 16, 2016, 01:47:05 AM »
Welcome to RR Ed.


Quote
the concept of reading in a PWM from a stepper driver to be converted to PPM output. It would be a dirty process which would make most programmers AND electronics guys scoff at the backwards logic in doing it
just wouldn't do it! impala

     marlin and RAMPS seems a little over kill for a servo arm,  how you gonna power the pins on "Aux 1" for the servo. 'servo's will draw more current than the on board 5V reg can give " could use one set of pin for a battery " leaves 3 servo pins" properly more  with aux4.
then you need to know gcode M280
M280 P11 S0-S90 ( servo through min to max).
       pin    value
not something I played with

  think when most people use a ramp like this they manually input the positions getting the gcode for the first layer of a model is easy, can open the file with window "word", that still doesn't translate to servo position, not seen a example of anyone doing it yet.

   early days of reprap designs used servos but never intended to support an arm motion, apparently servo's wasn't a very good choice and moved to steppers, with servos only being used with preconfigured routine in bed levelling and nozzle wipe action.

« Last Edit: October 16, 2016, 04:58:46 AM by jinx »
I build bots

MEgg

  • Sr. Member
  • *
  • Posts: 262
Re: robotic drawing arm
« Reply #9 on: October 16, 2016, 08:09:01 AM »
[...]
I have no coding experience but have changed or added g-codes to models sliced in repetier host.
[...]
Any ideas?
Thanks

Hello and a warm welcome to RR.

From reading all that is written in this thread I think  learning a bit C for programming (the Arduinos and of course other stuff)  is easier than poking g-codes around.
Programming is not a big monster as some people see it.
 ;)
The mathematics -as bdk6 said- behind your project  can be better formulated in C than in g-code, but that is what I am seeing as a 3D printing beginner, I rather have the impression that gcode poking is even more tedious than assembler programming.
 ;)
Also the whole thing packed into some functions may be usable for later projects that you will make, whereas
I think the gcodes will be quite specific to one project.

So if you are willing to learn C and programming with C, I am sure the whole RR will help you to find good learning material and answer questions.


1st project: Dagu 5 Rover + Dagu - 4 Channel DC Motor + Red Back Spider robot controller + Raspberry B+
Chassis + wheels: https://picload.org/image/dggroior/20150831_028.jpg
current: https://www.keepandshare.com/userpics/m/a/r/k/usegg/2016-04/sb/img_3480-79682018.jpg

Impala

  • Member
  • *
  • Posts: 189
  • Henbane Wellington Soufflage
Re: robotic drawing arm
« Reply #10 on: October 16, 2016, 08:25:57 AM »
RE
I didn't say it was the best way or right to do it. I just said that it can be done. I have 3 cnc machines. They all use serial to drive the cnc controllers. So its completely possible to intercept that COM and convert an output to PPM. It would be an ugly process. But it could be done, and it would have to run real slow for positional reasons. That's all I'm saying. Agree or disagree.

 

* Search


* Recent Topics

2D Side Scroller Cyberpunk themed by Killer Angel
[November 12, 2019, 07:56:15 AM]


The unnamed (yet) quatruped spider project by tinhead
[November 09, 2019, 05:58:16 AM]


Ebot SL by erco
[October 31, 2019, 04:27:36 PM]


Discord anyone? by tinhead
[October 20, 2019, 05:35:59 AM]


MKS Gen L 1.0 by lllloydo
[October 06, 2019, 01:24:26 AM]


Saturn pics anyone by viswesh
[September 28, 2019, 11:55:53 PM]


Hello Robot Rebels by Passixs
[September 15, 2019, 10:19:10 PM]


All Ya'll. And me. by James
[September 09, 2019, 10:35:19 PM]


MSD - Motorized solder dispenser (Work in progress) by James
[September 09, 2019, 08:45:29 PM]


It may be dangerous to work in the virtual realm by ZeroMax
[September 05, 2019, 05:55:16 PM]


"1984 Nixie Time" by Gareth
[August 25, 2019, 12:21:58 PM]


Just wanted to say Hi. by ErwinCanto
[August 18, 2019, 10:11:28 PM]


SDR (Software Defined Radio) by Gareth
[August 14, 2019, 01:12:21 PM]


PLX-DAQ by AmandaG
[August 06, 2019, 01:58:42 PM]


DIY Yellow Servo by AmandaG
[August 06, 2019, 01:08:09 PM]

* Recent Posts

Re: 2D Side Scroller Cyberpunk themed by Killer Angel
[November 12, 2019, 07:56:15 AM]


Re: The unnamed (yet) quatruped spider project by tinhead
[November 09, 2019, 05:58:16 AM]


Re: The unnamed (yet) quatruped spider project by Nemesis
[November 09, 2019, 03:29:02 AM]


Re: Ebot SL by erco
[October 31, 2019, 04:27:36 PM]


Re: 2D Side Scroller Cyberpunk themed by Killer Angel
[October 31, 2019, 09:57:48 AM]


Re: 2D Side Scroller Cyberpunk themed by Killer Angel
[October 31, 2019, 06:01:53 AM]


Re: 2D Side Scroller Cyberpunk themed by maelh
[October 30, 2019, 03:06:28 AM]


Discord anyone? by tinhead
[October 20, 2019, 05:35:59 AM]


The unnamed (yet) quatruped spider project by tinhead
[October 20, 2019, 05:28:14 AM]


Re: 2D Side Scroller Cyberpunk themed by Killer Angel
[October 17, 2019, 09:44:06 AM]


Re: 2D Side Scroller Cyberpunk themed by Killer Angel
[October 17, 2019, 08:16:11 AM]


Re: 2D Side Scroller Cyberpunk themed by Killer Angel
[October 14, 2019, 08:52:20 AM]


2D Side Scroller Cyberpunk themed by Killer Angel
[October 14, 2019, 03:32:40 AM]


Re: MKS Gen L 1.0 by lllloydo
[October 06, 2019, 01:24:26 AM]


Re: Saturn pics anyone by viswesh
[September 28, 2019, 11:55:53 PM]