[feature] Adaptive / Feedforward Temperature setpoint

[dc42]

@timschneider said in [feature] Adaptive / Feedforward Temperature setpoint:

ok, A40 is working - but shouldn't A100 act like A0 if A100 can not be maintained? Instead it was acting like T0.

I've reduced the maximum allowed from A100 to A50 in rc2, which I think should work.

[EDIT: Adrian's post above suggests that it doesn't.]

[dc42]

@Adrian52 said in [feature] Adaptive / Feedforward Temperature setpoint:

I guess if one is using the feedforward in the way intended, the temperature shown is the target temperature

That's correct, the target (as displayed by DWC and PanelDue) remains the same but the feedforward correction is added to it internally.

@Triet said in [feature] Adaptive / Feedforward Temperature setpoint:

It is impossible to know how far the current temperature deviation is.

I'll look at adding the current feedforward boost to the object model.

EDIT: I've added the boost parameters to the OM.

[Adrian52]

@dc42 On my system, the highest A value that works is 48

[Adrian52]

To see if I could get the hotend to follow the forward temperature more closely, I tried removing the silicone sock from the revo heater, to see if I could get faster cooling. I redid the pid tune without the sock, and this is the plot printing a 100mmx20mm cube that has three small cylinders attached to one end. The cube walls print at 140mm/sec, and the cylinders around 20mm/sec. The cube has no fill or top, but the initial part shows printing the bottom infill

It then cycles between the fast cube walls and the slow cylinder walls. I was suprised how well controlled the temperature is under these conditions. The print weighed exactly the amount predicted by the slicer, so no underextrusion. The cube walls were printing at 22cumm/sec (o.4 nozzle, 0.2layers). The S parameter was set to 1

Would be interesting to plot the feed forward boosted temperature on the temperature chart - is this possible?

[jay_s_uk]

@Adrian52 you could plot it with BtnCmd if its in the object model

[Triet]

@Adrian52 Wouln't you need to repeat the same print (with/without silicon sock) to properly quantify the effect? What are you comparing to?

[Adrian52]

@Triet Indeed - I was just looking at the feasibility of leaving off the sock. I was concerned that it would make temperature control unstable, but this doesn't seem to be the case. I thought a next step would be to plot the boosted temperature against the actual temperature, but waiting for an update that has the boosted temperature in the OM. On a learning curve with btncmd too - not used it before. Will aim to do a more formal comparison, including maximum speed and print quality.

[Triet]

@Adrian52 I share the same interest. If I get somewhere customizing DWC to show the temperature deviation I will post my findings.

By the way, removing the silicon sock to facilitate better temperature control is a brilliant idea.

[dc42]

@Triet said in [feature] Adaptive / Feedforward Temperature setpoint:

By the way, removing the silicon sock to facilitate better temperature control is a brilliant idea.

Even better would be to replace the hot end by one with much lower thermal mass and heating/cooling times, such as the E3D Revo.

[Adrian52]

@dc42 I am in fact using a revo micro on my delta, and just ordered a 60w heater, to see if it shortens the heating time. Hope it doesn't melt my part cooling duct!

[Triet]

@dc42 The thoroughgoing extrapolation of this idea would be an
INo Trident

[Adrian52]

Another experiment, with a 60W e3d revo heater, and no socks. The print is a 20x100mm cube, and a set of 6 8mm diameter cylinders. The cylinders print quite slowly and the cube at 140mm/sec.

This is an excel graph of csv data captured by btncmd (not worked out how to plot calculated values in btncmd).
I added the active temp to the boost (a+b) to compare to the actual temp(current). You can see there is a bit of a lag on both the heating and cooling phases.
I also plot the extrusion volume, and you can see that the boost anticipates the increase in extrusion, although not by enough to align with the current temperature. I plotted extrusion+active temp(e+a) to move the extrusion line up to the area of the current temp line.
Not quite sure why the active +boost is below the current temperature in the initial phase - this is the relatively slow printing of the first layer.

[Triet]

@Adrian52 If the command would allow an option to limit the extrusion (=speed) to match the actual temperature, it would be much better, as layer adhesion would be optimal. Delamination and sudden breaks under mechanical load would be a thing of the past.