While calibrating the AR4 MK3 I found out that it got stuck on the 4th joint, to my mind the joint rotates the wrong way during calibration. (See video) Because of this if you don't pay attention the cables get stuck.
https://anninrobotics.com/wp-content/uploads/2025/08/AR4-MK3-J4-calibration-flipped.mp4
https://anninrobotics.com/wp-content/uploads/2025/08/AR4-MK3-J4-calibration-flipped_2.avif
J4 does turn the right way during manual use in the program so the polarity of the stepper is correct.
Is this normal behavior and should I do my cable routing better or is there a value to be changed in the code?
Thanks in advance,
Daan Sijnja
Are the cables being pinched or causing the joint to jam or lock up? It does look like the J6 cables should be a bit further to the right and tied to the J5 limit switch cable.
@chris-annin Thanks for the reply, I can try doing that but I don't know if that wil fix the issue because it will still hit the belt used for rotating J4 (See Image below)?
I found out what is wrong, i build the J4 stepper motor with a 90 degree anitclockwise rotation i found this after analyzing the startup video you made I saw that your j4 arm doesn't need to rotate as far as the one I put together
https://anninrobotics.com/wp-content/uploads/2025/08/AR4-MK3-J4-calibration-flipped_4.avif
This is the point where the arm stops in the video,
https://anninrobotics.com/wp-content/uploads/2025/08/AR4-MK3-J4-calibration-flipped_5.avif
This is the the Arm that i built in roughly the same position as in the video.
https://anninrobotics.com/wp-content/uploads/2025/08/AR4-MK3-J4-calibration-flipped_5.avif
