Industrial Arm as CNC something?

[avayan]

Hi Group,

I was able to take this industrial robot and interface it through MACH3 using some of my open source design bipolar stepper motor drivers, namely the AE-MDL-STPR8811. I am using three DRV8811 at various currents to drive its three unipolar motors, wired as bipolar. The robot is very strong and it was able to push a rather heavy tool cart as it moved. You can watch a video here:

YouTube - DRV8811 Driven Industrial Arm Robot
The question I have is this. If I want to control the motion coordinates via some form of GCode, since this is not a linear X-Y system (the Z is still as Z as any other configuration), but I guess polar, what is the best way to get the transformation accomplished. Is this something MACH3 does?

Let me explain what is my ultimate goal here. I want to use the robot as a passive component pick and place. Seems like overkill, but since it is working, I figure I might as well use it! On my PCB board tool, I can get a Pick and place file which details the coordinates each component is located, along with its rotation. So I figure I should be able to generate an easy G Code filw with this coordinates.

Except that although each coordinate is easy to reach by moving linearly in the X and Y directions, I must now move radially both arm motors to reach whatever X and Y coordinate I am to move to. Even if I do not need to displace in the Y axis, the robot would need to move both motors to move in a single axis. Hopefully I am making sense here...

Has this been done before? I am kind of stuck, so any insight would be highly appreciated. Thanks!

JIQ

[samco]

You would have to do transforms in the gcode. some sort of pre-processor. Mach doesn't do forward and reverse kins. Maybe you could do it in cam post. Emc2 has a setup for that style arm (scara)

EMC Documentation Wiki: Kinematics

KINS

http://wiki.linuxcnc.org/uploads/scara_vismach.png

EMC Documentation

It is not trivial - but it does the work so that the machine can be programed in xyz coordinates