1. Control program and electrical system abnormalities
Abnormalities in electrical and control parameters can lead to system misjudgment or insufficient power output, thus triggering overload protection.
Feedback signal interference and misjudgment: Interference in the encoder signal, insufficient battery voltage, or mechanical zero offset may cause the controller to misjudge the position and output abnormal current commands. At this time, the motor is not actually overloaded, but the system triggers protection due to excessive closed-loop error.
Power cable and joint failure: Long-term bending of the motor power cable may cause partial strand breakage, and the joints may become loose or oxidized due to frequent vibration. This will cause high impedance and voltage drop, causing the actual input power of the motor to be insufficient. The controller will continue to increase the output to maintain speed, eventually triggering overload.
Improper setting of control parameters: If the acceleration and deceleration time of the drive module, overload protection settings and other parameters are not properly configured according to actual working conditions, or the gain parameters and torque response speed of the servo system are not optimized for high loads, it can easily lead to slow response or even overload of the motor during start-stop or heavy load.
2. Resistance and wear of mechanical structure
Abnormal resistance of the mechanical transmission link is the most direct physical cause of reducer overload.
Internal wear and poor lubrication of the reducer: Long-term high-load operation will cause internal gear wear, tooth surface peeling, or bearing jamming of the reducer; if the grease is aged, dried, deteriorated, or insufficient, it cannot form an effective oil film, which will intensify metal friction and significantly increase rotational resistance.
External mechanical structure interference: Loose bolts at the connection between the robot arm connecting rod and the gripper, or foreign objects blocking the gripper clamping mechanism will increase additional mechanical transmission losses.
Balancing device failure: For palletizers with pneumatic or spring-type balance cylinders, if the balance cylinder leaks, the preload force is insufficient, or the hinge points are loose, the servo motor will need to output additional torque to maintain the posture of the robotic arm, which will indirectly increase the burden on the motor and reducer.
3. Load matching and operating conditions imbalance
The equipment Selection does not match the actual production demand, or the operation is not standardized, which is a systemic inducement to overload.
Improper power supply and matching: During the equipment design or operation stage, if the actual load, speed and impact conditions are not accurately calculated, and a small-size reducer or a low-power motor with insufficient power reserve is blindly selected, the equipment will easily lose steps or cause an overload alarm when faced with an instantaneous impact load.
Overloading and illegal operations: The actual palletized workpieces are overweight, the number of palletizing layers exceeds the standard, or frequent extreme speed starts and stops during the production cycle, temporarily increasing the workload, will cause the reducer to operate overloaded for a long time and lose the safe operating margin.
Heat dissipation and environmental issues: The control cabinet filter is clogged, the driver fan fails, or the ambient temperature is too high, which will cause the temperature rise of the motor and driver to overlap. Even if the load is normal, continued high temperature will trigger a thermal protection shutdown.
Troubleshooting suggestions: When dealing with overload faults, the principle of "electrical first, then mechanical, first external, then internal" should be followed. The operating data of the servo motor (such as load current curve, torque output peak value) can be retrieved through the control cabinet, and combined with manual turning of joints to feel resistance and inspection of mechanical structures, the source of imbalance can be accurately located to avoid blind replacement of core components.
