Setting up four Mechaduinos with RAMPS 1.4 3D Printer controller -> Motors vibrate heavily!

[Dahah]

Hi all,

Situation: I am building a hangprinter (hangprinter.org) and therefore I use 4 Mechaduinos with Arduino Mega and RAMPS 1.4 3D Print board like shown in this diagram: http://www.hangprinter.org/doc/v3/media/Hangprinter_electronics_diagram_Mechaduino_RAMPS1.4_V2.3.jpg 

I flashed the arduino and the 3D Printing stuff works (Marlin, Slicr, Pronterface).

I set the I2C adress for every motor and changed the look up table after the c-routine in the Mechaduino firmware.

Problem: Everything seems right, but my motors make an awfull noise and vibrate heavily! 

What I've tried: 

1. If I disconnect the 5V VIN on the Mechaduinos and let the 12V plugged the vibration stops. So I changed the 5V VIN wiring. If I connect the 5 V to the Mechaduinos the motors start vibrating.

2. I changed the 12V to 5V level shifter and used the one Tropical Labs recommends. But the motors still vibrate.

3. I changed the PID values. First I set "pKd = 0" Then I lowered the pKp-value step by step. But even with 0.1 there was heavy Vibration. Nothing changed during the step down tuning. If the vibration would have stopped I would have increased the pKd-value again. 

What can I do? Where is the problem? Did I do the right PID tuning???

Thanks for help!

 

[david.h...@googlemail.com]

I made a small video with one of four motors plugged: https://www.youtube.com/watch?v=UOfoPIc4YRc&feature=youtu.be

I use the mechaduino firmware from the hangprinter github rep., that can be found here: https://github.com/tobbelobb/hangprinter/tree/Openscad_version_3/firmware/Mechaduino_subtree

[lucas...@gmail.com]

Same here, but using the firmware from the Mechaduino GitHub repo. Calibration table loaded. Default PID.

The step response graph is the following:

[david.h...@googlemail.com]

My motors are quiet if I just use the mechaduino without the 3d printer firmware and I2C bus: C-routine runs without vibration. @lucas Are you running an Arduino and RAMPS, too? I used the following wire diagram: 

[lucas...@gmail.com]

David, 

I didn't finish all the cabling, but I'm going in that direction (actually building a HangPrinter v3).

What I found was that the problem were in 3 of 4 motors. These 3 motors were recentrly recycled from my first 3D Printer (4 years old) that were running with a Rumba board and CoolDRV r2 (based on 8825 chip). 

The fourth motor was identical to the other 3, but brand new. This motor never presented the oscillating and noisy issue.

What I made was to raise the  pLPF from 30 to 60. Here are the response graphics, Before and After:

The following is the graph for the 4th motor (brand new). Never presented oscillation and it achieves the stationary position without that bounce.

I hope this helps.