Makelangelo – tuning it in
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Ok I finally got around to build a larger iteration with the forementioned spool and external cord guides.
In Configure.h, PULLEY_PITCH is the spool circumference right? Is this the main parameter to change if the movements are larger than expected? I get (69,2) cm when commanding (60,0) cm. I have the measured spool circumference and no winding on the spools.
And about the “Home” function…
– When using Makelangelo SW:
What exactly does “Home” mean, is it the starting position? And why does it seem to be fixed at a certain distance from the top border of the machine, even when pressing “Set home” and being somewhere else in the machine area? (the GIU shows the pen go back to the original home point)– When using Gcode, e.g. with your GcodeSender tool:
Is setting/using the Home position relevant for someone using only Gcode to run the machine? I can’t find any use for it, since only the boot-up position seem to define coordinates X0 Y0.The home position is a known starting location for the pen. It is above the edge of a sheet of A2 paper. At shows we would draw many pictures and homing to 0,0 was annoying. Either the pen goes there first and then I slide the paper under the pen holder OR I put the paper up and then I can’t see the home position. Better a home position that is not covered by the paper.
Clicking “set home” tells the robot that the pen is at the home position. Otherwise it has no idea if you are ready.
In theory some code could be written to customize the home position, and most users would keep their existing (default) home position.
I’ve tried to increase the movement speed (not for drawing reasons), but found that the motors start jerking oddly when I go over speeds/accelerations of 5000 (running GCODE: “G0 F5000 A5000”). Am I doing something wrong or is there a upper limit for how fast the system goes?
Could it be the commands for movement I’m sending? I’m running “G0 Xnnn Ynnn”.
I haven’t noticed any difference between using G0, G1 or even simply G. And Makelangelo SW seems to be using G00. Is there any difference between these?At some point the pulses that move the motors are going to be faster than the motor shaft can achieve. then steps will be missed. The same is true for acceleration. The default numbers in the software are my best guess. If you find better numbers, please share with everyone.
G0 and G1 are the same. In the literature, G0 is a “rapid linear move” – travel at max speed. G1 is supposed to be a slower travel (such as when a tool is working). In the firmware I use the two for the same thing.
I can share the following data I gathered with my machine, when moving from X0 Y0 to X600 Y60.
F A Duration
1000 1000 13.5s (super smooth movement)
3000 3000 6.2s (smooth movement)
3000 6500 5.9s (smooth movement)
5000 500 6.4s (some noise/jerk)
5000 5000 4.6s (some noise/jerk)
5000 10000 4.6s (some noise/jerk)
6000 6000 3.8s (kinda jerky)
6000 12000 3.7s (kinda jerky)
8000 8000 3.8s (jerking so much that losing accuracy)Conclusions:
– The Acceleration value seems to benefit being over a certain treshold not too much less than the Speed value. But once it surpasses the Speed value, not much difference is made.
– I need to stay under F5000 A5000 to avoid jerking. I have a feeling that’s lower than it ought to be.I can’t remember what the default settings were, since I’ve changed them so many times since. Can you do me a favour and have a quick look, and maybe even try running at higher speeds to see when it starts jerking for you?
to accelerate faster than top speed would mean you go from zero to top speed almost instantly.
on both M3 and M5, the defaults are accel 5000 speed 9000.
A5000 F9000 is super jerky for me – wierd that your motors can run smooth on that and mine can’t. Could it be that I’m using 200steps/rev motors and you 400?
Everything else should be the same (1/16th microstepping, same RAMPS board set to 1/16th, same firmware). Only other difference is I’m using larger pulley diameter than you but that cant be it.Heck yes! Your motors have to move twice as far in the same time. You might get away with A2500 F4500.
Hmm don’t they need to move the same amount, but just that mine does it in less steps than yours? Does that really mean mine need to go faster?
And woudn’t the motor setting in configure.h compensate for that nonetheless?Sorry for keep bothering on this minor issue! 🙂
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