iCubWaterloo01 S/N:044 – Mechanical issue with robot's neck

[paliasgh]

Robot Name 🤖

iCubWaterloo01 S/N:044

Request/Failure description

Hello, we are having an issue with the neck of our robot. When the head moves to certain positions, pitch and roll motors get disabled as the roll DOF gets stuck (is difficult to move physically).

Detailed context

When the problem happens, we can hear a clinking sound from pitch and roll motors (not sure if both or only one). Joint 0 (pitch) gives this "i2t limit exceeded" error and goes to HWF fault mode. Joint 1 goes to idle (second picture, sorry the photo is blurred).

When this happens Joint 1 is difficult to move at a certain point (near 0). The mechanism in the neck gets mechanically stuck somehow. You can see the issue and hear a noise in these videos. We took the belt out to see if it was the motor or the other side. It was the other side (the neck). The movement is not smooth, is noisy, and it may fully get stuck, requiring us to move it back and again forward to pass that point.

https://github.com/user-attachments/assets/c6fac6f5-43d6-4e8f-a8c7-cba9e60e5c4d

https://github.com/user-attachments/assets/b141bd96-70dc-4340-82ef-b17d015b69d6

https://github.com/user-attachments/assets/9cdbcee1-ec48-4fb8-a5dc-93786e779358

Thanks for your assistance!

Additional context

No response

How does it affect you?

We are in the middle of running an HRI experiment that is getting affected.