I have an application that uses an Allen Bradley servo with a brake and a linear actuator to lift a plate vertically. While maintaining a position, the servo drive (Kinetix 5500) will occasionally fault due to over-torque.
I'm thinking it could possibly be due to mechanical issues i.e. bearings in the actuator but my initial thought would be that it would fault while moving up/down as well, so far I've only ever seen it fault while holding a position. This leads me to suspect that there may be something off in the control loop. I'm not involved in the setup but I know we use load observer and I reckon we use auto-tune. Other than that, I wonder if it's something to do with the brake. I also read about mechanical resonance in the manual which seems like a stretch but it could be contributing, the frame that the actuator/motor is attached to does vibrate a fair bit.
I'm familiar enough with basic motion control using Allen-Bradley and understand the basic concepts behind the servo/control loop. However I'm at a loss for why the servo/drive would spontaneously over-torque while maintaining a position.
How would you guys approach troubleshooting this further/solving this issue?