Tuning input shaping and PA 3.5b3

ctilley79

I'm having a little difficulty tuning PA and Input shaping. I'm finding that on a direct drive extruder, I'm having double the amount of PA when Input Shaping is enabled. With, ABS, normally I set PA to 0.04 whereas with IS, I'm having to go with a value of 0.08 or even more. What's the relationship between IS and PA that would require doubling?

I'm also finding a little difficulty tuning Input shaper itself. On long spans IS seems to work ok. but on spans say around 10-20mm the results are not ideal. This might have something other to do with IS, or the IS plugin isn't really giving me good values.

My printer is a voron 2.4 CoreXY with Duet 6HC and 1LC running in SBC mode. Here are my settings

M350 X16 Y16 Z16 E16 I1		           ; configure microstepping with interpolation
M92 X160.00 Y160.00 Z400.00 E562.00	   ; set steps per mm
M566 X600.00 Y600.00 Z300.00 E4000.00	   ; set maximum instantaneous speed changes (mm/min) AKA Jerk
M203 X16800.00 Y16800.00 Z750.00 E5000.0   ; set maximum speeds (mm/min)
M201 X3000.00 Y3000.00 Z350.00 E5000.00    ; set accelerations (mm/s^2)
M906 X1000 Y1000 E900 I40		   ; set motor currents (mA)and motor idle factor in per cent
M906 Z1100 I80			           ; set motor currents (mA)and motor idle factor in per cent

print settings

!80mm/s perimeters 2500mm/s² Acceleration and 
M593 P"zvd" F43.0 S0.0
M572 D0 S0.08

This is along the X-axis and seems to be the worse axis.

But along longer spans, things look pretty good. No hint of ringing at all. This was along the Y axis.

Even at 0.08 corners are still rounded.

Diagonals also give me an issue where one motor is doing more work than the other.

This is strange because the ringing is intermittent and doesn't necessarily occur where You think it would. That ringing is along the y axis.

Without IS

With IS ZVD 43.0hz 0.0

dc42

@ctilley79 I have just fixed an issue in 3.5b3 that caused incorrect extrusion on tool boards under some conditions. See https://github.com/Duet3D/RepRapFirmware/issues/848. This may be relevant to the issue that you see.

The fix will be included in the forthcoming 3.5beta4 release. There is an interim build containing the fix at https://www.dropbox.com/sh/in0t2j68ic66oa8/AADv_6WzRy07H6MhBOrkDt23a?dl=0 if you wish to try it.

The other issue that may be relevant to what you are seeing is this one https://github.com/Duet3D/RepRapFirmware/issues/774. I expect to work on that next week.

dc42 created this issue in Duet3D/RepRapFirmware

closed Tool board extrusion issues reported by Andy #848

T3P3 created this issue in Duet3D/RepRapFirmware

closed Force steady speed segment in accelerate-decelerate moves to reduce vibration and facilitate input shaping #774

ctilley79

@dc42 I was already on a similar build that fixed the E motor running backwards issue. Is this a newer build than that one?

Edit. I may have answered my own question by clicking on the github issue lol