Makelangelo 5 performance tuning

[Dan]

I’m trying to get the fastest possible speed and the best quality drawing from Makelangelo 5. Surely you are, too.

Currently I’m running with

acceleration=500
draw speed=5000
max speed=12000

I know the machine can move at 12000 without missing any steps or stuttering. I want to believe that it can draw at this speed, too.

I find above areas with many very short line segments make the machine begin to stutter, which lowers the quality of the drawing.

I have tried drawing from the SD card. No change, so Serial communications are not the bottleneck.
I have disabled drawing to the LCD panel in case it was slowing things down. No change, so LCD refresh is not the bottleneck.
I have tried increasing the MAX_SEGMENTS from 32 to 64 so that it can buffer more commands ahead. No change.
I have tried regularly printing out the number of segments currently in the segment buffer. Almost always >2, even when there is stutter. So that’s probably not the problem.
I have tried raising the acceleration as high as 5000. Stutter is different, not better.
I have tried to lower the quality of drawings so that there are less short line segments, especially in curved areas. This seems to help a bit.

I have NOT tried switching to DRV8825 stepper drivers.
I have NOT tried changing the microstepping.
I have NOT tried DC motors with encoders and ODrive motor controller.
I have NOT tried to detect when there are many short lines and slow down automatically.

What have you tried?

[Dan]

https://github.com/MarginallyClever/Makelangelo-firmware/issues/51

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