LINEARDELTAKINS(9)

📦 version 2.9.4, in debian bookworm, debian trixie, ubuntu questing, ubuntu resolute, ubuntu stonking

💖 LINEARDELTAKINS 💖

okay bestie, so this is lineardeltakins — the kinematics for a linear delta robot 🦋 and yes it's giving "i build weird tall printers" energy and i'm obsessed.

✨ SYNOPSIS ✨

loadrt lineardeltakins

that's it. that's the whole vibe. load it and go 💅

🌸 KINEMATICS 🌸

so the kinematics model is the moment for a rostock/kossel-style design — three joints arranged in an equilateral triangle. and listen, (0,0) is always the center of the working volume, no cap, that's just where it lives.

Joint 0 sits at (0,R), and then every subsequent joint is 120 degrees clockwise from the last one. and heads up bestie — joint 0 is not at zero radians, ok? don't come for me about it, that's just how it is. 🙈

the length of the arm is L. iconic.

so like, joints 0-2 are the linear carriages. and then axes ABC and UVW get passed through unchanged in joints 3-8, which means e.g. A can still be used to control an extruder 🎀 slay, multitasking.

🎀 PINS 🎀

  • lineardeltakins.R float in — the effective diameter of the platform. and this is the part where people get confused so pay attention: R is different than the distance from the center of the table to the center of the belt/smooth rod/extrusion that the joints ride on. like, not the same thing at all. in RepRap delta parlance, R is DELTA_RADIUS, which is computed as:
DELTA_SMOOTH_ROD_OFFSET - DELTA_EFFECTOR_OFFSET -
DELTA_CARRIAGE_OFFSET.
  • lineardeltakins.L float in — the length of the rod connecting the carriage to the effector. in RepRap delta parlance, L is DELTA_DIAGONAL_ROD. yes, that one. 💜

⭐ NOTES ⭐

okay so the tea: the R and L values can be adjusted while LinuxCNC is running. fr fr, you can.

but. BUT. 🚨 doing that while in coordinated mode will lead to a step change in joint position — which generally will trigger a following error if you're in joint mode with the machine on. so like… maybe don't? or do, but know what you're signing up for bestie 😭

and that's the whole page! this absolute banger of a manpage is brought to you by LinuxCNC Documentation, dated 2013-07-11, filed under LINEARDELTAKINS(9). go build something triangular, you're the main character 👑✨

📦 where this page comes from