I've built a little Stewart-Gough hexapod platform with 6 steppers and a Rumba32 board. So far I have it built and Marlin drives all the motors properly. I had thought I would be able to run stock Marlin as a motor driver, and pass 6-motor move instructions as G-code from another piece of software that would handle the kinematics calculations. But, the extruder axes can apparently only be driven simultaneously via mixing instructions, and there's no homing. What's currently the best way to get a 6DoF platform working with a Rumba32 board?

A couple of other possibilities I'm exploring:

Figuring out how to port Marginally Clever's Stewart Platform firmware from the 8-bit Rumba to the Rumba32. It seems like it ought to be straightforward but I'm having trouble finding a resource that I can use to learn how to do it. It looks like PlatformIO should be the right direction?

Trying to get DerAndere1's 6DoF Marlin fork working on my board. I don't know how to marge those differences into the latest bugfix version to get it working, I'm not sure if that's even a thing.


Anyone know of a better idea than these that I should be exploring instead, or able to point me to a guide I can use to pursue one of the paths I've identified? Thanks in advance.

I only just stumbled on this post. RepRapFirmware currently supports up to 15 axes (depending on the board) + extruders, so using RRF you would be able to drive the 6 axis motors independently from GCode commands. One of our users is about to start implementing Stewart platform kinematics in RRF, which would allow Cartesian + tilt coordinates to be used instead.

I don't know whether there is a port of RRF for the particular STM processor used in the Rumba32. If there is, it will be at [github.com].

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

6 axis support from my fork https://github.com/DerAndere1/Marlin was merged into Marlin bugfix-2.0.x and first post-merge fixes are ready for testing at https://github.com/MarlinFirmware/Marlin/pull/22056. But you would have to add the reverse kinematic model and kinematics-related code for the steward platform yourself.

Best regards
DerAndere