Choosing a stepper or servo for a small positioner, low vibration

[Reddinr]

BTW, has anyone uploaded a video to this site? I still am having trouble with that. I get an error message once the upload gets to 100%.

 

[graham-xrf]

BTW, has anyone uploaded a video to this site? I still am having trouble with that. I get an error message once the upload gets to 100%.

I have uploaded two videos. I made them MP4, and I tried to keep them short.
You can very likely figure out what might be the problem if you ask @vtcnc

 

[whitmore]

I'm a stepper rookie but an experienced photog.
I think the challenge with a stepper will be the 'buzzing' that occurs as a result of the motor holding position. My gut says that unless there is zero load on the motor the motor may vibrate as it's holding position.

It used to be, all small hard drives had stepper motors for moving the heads. They didn't hum
enough to disturb the fine position resolution required. If you only want to move a camera,
you can derate the coil excitation current so there's no humming. It is also possible to
use a belt drive, which is pretty good at vibration isolation if a motor DOES hum.

... and I know where to find lots of old hard drives that didn't fail because of motors

 

[spumco]

Re: vibration...
Have you gone through the tuning procedure on the OEM750? Looks like you can dampen the resonance by fiddling with some pots on the top of the drive.

 

[Reddinr]

Hmmm. I added a follow-up on my video/site-related thread for vtcnc to look at. Seems the video upload problem is a problem for some. Might shoot him a PM too.

I have not gone through the tuning process yet on the OEM750. There are ways of reducing current and tuning the loop using serial commands, which I will do once I get the right-sized stepper hooked up. I have ordered a Nema 17 stepper to try out. I also have some old hard drive steppers. Seems like most of the ones I have are 5 wire, unipolar drives that I can't use my OEM750X on. Are they typically bipolars in the old drives? The indexer makes the software part of the project very simple.