Accuracy Issues and Calibration Overview

[madgrizzle]

I made this post to talk about chain wrap. Review it and let me know if you think its correct. It’s how I understand it but that doesn’t mean its correct.

Chain Length Calculations

The explanation doesn’t take it into account, but the code does… It’s just a couple different steps. It was enough of a pain enough to wrap my head around over top so I wanted to just get through that. I’ll put a disclaimer in the post.

@dlang

also, the chain wrapped around the sprocket, and the rotation radius should not
be modified by the chain stretch factor. I think today it’s implemented by
modifying the distance per rotation number, I think it probably needs to be done
much more explicitly in the calculations.

The self-modified version of groundcontrol/firmware I’m using removes chain stretch from the chain wrap calculations. It also calculates the radius of the sprocket during chain wrap calculations as the average of chainPitchnumberofTeeth and chainPitch/(sin(180numberofTeeth)*2). It’s a micro-adjustment but it’s something I did nevertheless.

Yes, the effect of chain stretch accounted for by changing the mmPerRotation of each axis in controller.