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MarlinFirmware / Marlin

Marlin is an optimized firmware for RepRap 3D printers based on the Arduino platform. Many commercial 3D printers come with Marlin installed. Check with your vendor if you need source code for your specific machine.
https://marlinfw.org
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[FR] Supporting true Core-XYZ mode #21947

Open kyrreaa opened 3 years ago

kyrreaa commented 3 years ago

Is your feature request related to a problem? Please describe.

no

Are you looking for hardware support?

no

Describe the feature you want

Marlin supports all kinds of Core-?? setups with both normal and reversed pair of axis involved. It does however not appear to support a true Core-XYZ machine which I have created. I am currently testing it out longterm (stresstesting) and so far it is proving quite reliable, but I am running a modified Repetier Firmware to do so. It needs a full kinematic for X, Y, Z -> A, B, C, D motor transform to move in all 3 axis.

Motor naming: (As seen from above) Back D C A B Front

Motor rotation is seen from shaft side of motor; face on. Contributions from Motors ABCD on motion XYZ: (+N denotes positive axis motion contribution from clockwise rotation of motor N.) X = +A +B -C -D Y = +A -B -C +D Z = +A -B +C -D

The ABCD data would then be: A = X + Y + Z B = X - Y - Z C = -X - Y + Z D = -X + Y - Z

It thus takes cartesian input and generates steps on 4 motors. None of which can just be paralleled...

Additional context

Videos of machine running: https://youtu.be/9iePaK2-MS4 https://youtu.be/Dk_4NDFEFgI

kyrreaa commented 3 years ago

Looking into the code I see that in order to handle this the code must be expanded to handle axis A, B, C, D as it is only enabled for a 2:2+1:1 transform now. The XYZ is overcomplicated here and overconstrained (meaning there are step combos that are illegal like stepping only a single motor) but when driven correctly it seems to balance out any binding etc well.

I guess AxisEnum needs to be expanded and renumbered before any other extensions are made. Planners get_axis_position_mm would need a third core axis check as well. The more I look at it the more work I see.

DerAndere1 commented 3 years ago

We added support for up to 6 axes to bugfix-2.0.x some days ago. You will still have to deal with the kinematics, though

kyrreaa commented 3 years ago

Wohooo! This will be fun! I'll see if my transforms from Repetier can be transposed into Marlin. What was done there was create a sort of transform matrix allowing user to define the way the axis convert thus being fully generic.

DerAndere1 commented 3 years ago

Have a look at the HANGPRINTER kinematics (https://github.com/MarlinFirmware/Marlin/pull/9180) that was present in Marlin 1.1.9 to see how to implement inverse kinematics for a machine with 4 kinematic axes that can be controlled by sending cartesian positions as G-code (Syntax: G1 Xxxx Yyyy Zzzzz Eeeee Fffff) .