Motoman K6SB Retrofit

I think that the STMBL might work with your motors. But the difficulty is getting a set of STMBL drives, especially with the current chip famine.

phasefreq wrote:

I guess what set in my mind that DH params would be hard to deduce on my own is that my PUMA arm has mechanical mixing (wrong term?) in the wrist- moving either of the involved servos alone causes both a twist and a bend of varying rates; to move only one joint, both servos need to move synchronously at different rates.

I _think_ that this can be solved in HAL, external to the kinematics. I have looked at it in the past and decided that it would work, but didn't have long enough with the robot to get there.

andypugh wrote:

I _think_ that this can be solved in HAL, external to the kinematics. I have looked at it in the past and decided that it would work, but didn't have long enough with the robot to get there.

By which I mean use standard DH kins, then intercept the joint position commands before they go to the motors and mix them there before passing them on.

So the original drives for this arm, which I’m going to pick up from a kind enthusiast in Ohio, are SGDR-SDAxxxx; that model number isn’t listed on @dm17ry ‘s site as being mechatrolink compatible unfortunately, but I haven’t dug through (or found) the documentation to confirm. 

I have an SGDH and an SGDV drive coming from eBay, both apparently mechatrolink ii and thus Dimitri-compatible. If I can convince them to operate the servos in my arm, I can eBay a few more of them- they are reasonably affordable. The Dimitry setup sure looks least complicated!

The servos in the arm, btw, are, from base to wrist: 
- USAPEM-07YR21
- USAPEM-07YR13 (2x)
- USAREM-01YR41 (3x) (what’s the difference b/t USAPEM and USAREM?)

Anybody know anything about the proprietary absolute encoder interface?

 

andypugh wrote:

I _think_ that this can be solved in HAL, external to the kinematics. I have looked at it in the past and decided that it would work, but didn't have long enough with the robot to get there.

By which I mean use standard DH kins, then intercept the joint position commands before they go to the motors and mix them there before passing them on.

 

This does sound like it’d work, good idea. I was actually able to get that arm (my smaller one with the mechanical mixing) to work using the linuxcnc-provided puma kinematics module after fooling with the nontrivial kinematics DH settings for a while. This arm, I am happy to learn, doesn’t actually use any mechanical mixing- looks like I should be able to deduce the encoder and gear drive ratios, measure the joint center to center distances best I can, and be in business. 

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So the original drives for this arm, which I’m going to pick up from a kind enthusiast in Ohio, are SGDR-SDAxxxx; that model number isn’t listed on @dm17ry ‘s site as being mechatrolink compatible unfortunately, but I haven’t dug through (or found) the documentation to confirm.

no, they are not.
googling for SGDR and CN102 reveals some motoman manuals mentioning
CN102 as PWM amplifier control power
CN1 as PWM signal
so i guess SGDRs are "dumb" amplifiers with a current feedback only. encoders connect to a separate board, not to servopack.

USAREM are "Regular" series motors
USAPEM are "Pancake" style

no, i don't know what protocol encoders use

info.ammc.com/hubfs/Partner%20Documents/...20-%20150133-1CD.pdf