MA012-003 Axis 4 Vibration and Position Error E-3114 at High Speed

Description

We have a NexBot Vision MA012-003 robot, SKU NXB-ROB-MA012-003, that has started faulting during our main production cycle. The robot is used for transferring stamped metal parts weighing approximately 22kg. During the fastest part of the motion path, we are getting an E-3114 (Axis Position Tracking Error) specifically for Axis 4. There is also a noticeable, high-frequency vibration or chatter coming from the Axis 4 joint just before the fault occurs. We have checked the end-of-arm tooling and all mounting bolts on the robot base, and everything is secure. If we reduce the program speed override to 80%, the error does not occur, but this has a significant negative impact on our throughput. The robot has been in service for about 18 months, running two shifts a day. We need to determine if this is a sign of mechanical wear in the gearbox or a tuning issue that can be corrected in the controller.

Symptoms

• Audible vibration/chatter from Axis 4 during high-speed moves.
• Robot faults with error code E-3114 (Axis Position Tracking Error).
• Fault only occurs when payload is near maximum (22kg).
• Slowing the program override to 80% or less prevents the fault.

Resolution

The investigation determined the root cause was suboptimal servo tuning parameters for the high-inertia load. The default gains for Axis 4 were not sufficient to maintain position accuracy during fast acceleration/deceleration with a 22kg payload, causing position overshoot that exceeded the configured limits and triggered the E-3114 fault. A remote support session was conducted to adjust the servo parameters on the R-10 controller. By increasing the proportional gain and velocity feed-forward for Axis 4, the system's response was stiffened, eliminating the vibration and keeping the position tracking error within tolerance at 100% program speed. The new parameters were saved, and the robot's full performance was restored.

Resolution Steps

1. Established a remote connection to the customer's R-10 controller.
2. Created a full backup of the current robot configuration and programs.
3. Instructed on-site personnel to place the robot in T1 mode and enable the servo monitor diagnostics screen.
4. Observed the 'Position Lag' value for Axis 4 while the operator jogged the robot through the fault-inducing path.
5. Navigated to the 'Advanced Servo Tuning' page and increased the Proportional Gain for Axis 4 by 15%.
6. Increased the Velocity Feed-Forward gain for Axis 4 by 10% to improve responsiveness.
7. Confirmed via servo monitor that the 'Position Lag' was now stable and within acceptable limits during the same motion path at full speed.
8. Saved the new tuning parameters and instructed the customer to monitor production for 24 hours to confirm the resolution.