About linear encoders

[Ben-PH]

I have a hobby project to build a linear motor powered 3d printer. I'm pretty comfortable with rust, but taking TTL output, driving linear motors, etc., is a bit new to me. would be keen to make a bit of project out of bringing in linear encoding and driving of linear motors, with a bit of help.

[ahdinosaur]

Hi @Ben-PH, welcome, sounds like a fun hobby project! ☺️

I'm not working on robokit at the moment, as I am focusing my attention elsewhere, but happy for you to contribute as you see fit. Let me know if you have any questions about why things are how they are. (See a blog post about my use of generics in robokit.) Open to any Rust expertise that improves what I came up with.

What bits of help do you need? Happy to be a rubber duck for you here. 🦆

Do you have a specific linear motor and linear encoder in mind?

[Ben-PH]

I'll check that out.

I plan to make my own linear motor, for better or worse. as for encoder, which I have no idea about.

The linear motor will be tubular. n52 25x5 round magnets in a nssnnssn config. I'll be relying a lot this article for setting things up in software to begin with, but the overall project is rust-first, so I'll be RIIR the code in there, then thinking about how to contribute to robokit or similar libraries: https://www.instructables.com/DIY-IRONLESS-LINEAR-SERVO-MOTOR/

I have no background in mech-eng, so I don't know how or where to sanity check my design, let alone optimise.

If this is an appropriate place to do this, I would appreciate your input:

• I'm using 25mm diameter, 10mm thick n52 magnets arranged in a nssnnssnnssnnss configuration, stacked into a 26mm ID 6061 aluminium tube
• I plan on a 3-pole forcer, hooked up to an esp32-family microcontroller.
• I may upgrade to a dedicated ESC at some point.
• Will use PID to position the forcer
• will set up some sort of automated profiling to tune and optimise the PID, and account for vibrations in the machine.
• The ultimate goal is to replace klipper, but for now, just controlling a linear motor of my own build would suffice.

[ahdinosaur]

@Ben-PH Oh wow, making your own linear motor, that's incredible!

If this is an appropriate place to do this, I would appreciate your input:

I wish I could help more, but I'm not a mechanical engineer either, barely an electrical engineer, so this is beyond my knowledge.

All I can say is that, from the outside, your plan seems like a good place to start. I'm sure once you get going you'll learn and adapt.

Good luck! 🙏