Motoman K6SB Retrofit

Hi xcp92,

I have not gotten to the point of actually controlling the arm with LCNC yet, my project has stalled due to other commitments.

I think you will need to implement some custom kinematics. I have not looked into it yet so I am not much help.

How are you controlling the original motors? Using the original drives? What control signal do they take? I went away from the original drives due to lack of information that I could find at the time.

At first i wanted to change the drives and servos, but it was way to expensive. Luckily i found some information about the servopacks online after some intensive searching. Now im using the original drives. Its relatively simple. Analog signal for Speed and direction with a 7i77 Mesa card. And some controlsignals for the drive, like enable and so on. I made a small pcb adapter to use the original wiringharness of the servopack to connect to the mesa card.

This is the webpage with the informations i found. There might be infos about the K6s:

spaz.org/~jake/robot/

@thefabricator03 - I have the exact same arm! I linuxcnc’d a unimate puma arm a couple years ago, and it works remarkably well in Cartesian mode with the arm simulator too. I’m using Mesa real-time Ethernet devices.

Unfortunately, I lucked out on the puma- all the linuxcnc inverse kinematics examples came setup for my arm with DH parameters and everything. I have not been able to find anything at all for DH or kinematic params for the K6SB. That’s my biggest sticking point right now. 

Please let me know if you find them / get your arm working in Cartesian coords!

Were you able to find the kinematics params to run in Cartesian mode? I can share my linuxcnc config if you want to show how the inverse kinematics are set up, but I need to find the DH parameters for my yaskawa arm somehow

EDIT: this is meant as a reply to @xcp92

Have you seen this tutorial:

linuxcnc.org/docs/html/motion/dh-parameters.html

You might only have to replace the lengths with those of your robot.

Huh I actually had not seen that one! Several years ago I tried to figured out the genserkins config for my puma arm before giving up and eventually finding an out of the box puma config that worked; with this page though I actually have a hope of doing it from scratch, or like you said, just replacing the link lengths.

Thanks a ton!

Anybody by chance know the harmonic drive ratios on these arms? Or know which document would contain them? I’m told they are params in the ERC controller, but since I lack said controller that doesn’t help me much