Need help configuring a pick and place machine??

Hi all!

I have been working on making my own pick and place machine and have already had great success but i need one more degree of freedom before its fully utilized.
This concept video shows a precision servo and a type of vacuum needle in place of a spindle and cutter and is sort of what i have already (minus the rotation ).


I need to be able to position that motor and tool to increments of a 360 degree circle (and limited to only one revolution so tubes or wires dont get wound up!!!).

I have been using steppers for most of my machines and i am pretty familiar with a general setup and stepconf, but in this case i need to use an actual servo because the vibrations of a stepper are too much and the parts would shift or come off of the tool.

I think this is where my knowledge of LinuxCNC starts to break down, i have never incorporated a servo in this software and am not even sure where to begin? how do i add a new servo axis to a configuration that already has 3 steppers?
and im not sure what you would lable this axis, but im sure its not standard practice. so im not even sure how to tell linuxcnc which part is rotating..

I have a bunch of servo motors with rotary encoders that i have been waiting desperately to find uses for.
I can buy drivers/amps or even build simple H-bridge circuits controlled by microcontrollers and interface those to software, I just am not familiar with that interface, what its called, where to find it or how to change it.

Thank you anyone for responses!!

yes u can add a rotation to an axis and also add servo's to Linuxcnc ,

linuxcnc is extremely flexible , for rotation around an axis this is Axis C , this can be added just the same as any other in your ini file
adding a servo axis depends on what type you have available and how the driver is driven , step direction or analog 10v etc .

this also depends on what interface you are using , and spare pins you have available

you may get some inspiration and ideas from my site www.placecomponents.com
although not running linuxcnc

fill in the gaps and let me know what you have and i'll help with the rest


Dave

Hallo cnccircuits,

It is simple to add that rotary axis to your machine. As the rotation is around the Z axis, we are talking about an C axis. I would recomend you take a servo amplifier you can drive wizh step dir sibnals, so all hal connections for all axis are very,very similar.

As a sim example you may want to look at gmoccapy_4_ axis.ini, it has x,y,z and c axis.

And if you want a special user interface, please read johns very good documentation.

gnipsel.com/linuxcnc/gui/index.html

Norbert

I have begun building a servo motor controller of my own flavor using a P8X32A microcontroller and an EG&G servo/encoder. so far i am successfully reading in the encoder and have started working on the h-bridge.

i hope to soon incorporate this into linuxcnc and I truly appreciate all of your input!!

I have finished the servo motor controller and the pick and place head.

I thought i would share some images and videos as all of you have been so helpful!!


This is the design i made of the pick head its self


And an image of the overall system (including the servo, pick head, homemade h-bridge driver and one Parallax propeller proto board)


Close up of the driver


A close up of the pick head


and a closeup of the rotating needle

This is a video of the head in operation, it is currently being controled via the serial RS232 port and a simple command set i developed. the sequencer is actually a Python script running on a PC.


And for those of you who are still with me, i figured why not just put the whole thing into orbit...