Precision 6DOF platform for laser optics

I am tasked with building a 6DOF Stuart platform for holding a crystal on an optics table. I would like to achieve sub micron position control. Commercial controllers are about $60K, so that is out of the question. Looking at the 34:1 Metal Gearmotor 25Dx52L mm HP with 48 CPR Encoder, I see it has 1633 counts per revolution on the encoder. Does anyone know the backlash in the gearing? I wouldn’t mind backlash if it is a known and highly repeatable value that can be compensated for in the software that will control this device. 6 of these motors carrying the linear arms on a stuart platform would probably get me close.
I also welcome any recommendations for small (nema 8) size steppers built into a zero backlash linear configuration with optical encoder.


The backlash is probably one or two degrees, though we have not characterized it beyond eyeballing a few motors. I don’t know what kind of unit-to-unit variance you can expect in the backlash, or how it might change on a given unit over time. Please make sure you aren’t counting on using $25 motors to replicate the performance of a $60k system!

- Ben

No, there is much more to the system than $25 motors, but price is not always indicative of quality or suitability to a certain application. I believe in this case I will look to direct drive 100+ thread per inch lead screws with zero backlash gland nuts. Thanks.