There are several viewpoints for reference in the analysis of servo motor jitter fault:
First,
1. When the PID gain adjustment is too large, it is easy to cause motor jitter, especially after adding D, which is especially serious, so try to increase P and reduce I, preferably not add D.
2. When the encoder wiring is wrong, jitter will also occur.
3. If the load inertia is too large, replace the larger motor and driver.
4. The disturbance of analog input port causes jitter. Add magnetic ring on the input line of motor and power supply input line of servo driver to keep the signal line away from the power line.
5. There is also a rotary encoder interface motor, which is easy to cause vibration in case of poor grounding.
Second.
1. Servo wiring:
A. check whether the standard power cable, encoder cable, control cable and cable are damaged;
B. check whether there is interference near the control line and whether it is parallel to or too close to the nearby high current power cable;
C. check whether the potential of the grounding terminal changes, and ensure the good grounding.
2. Servo parameters:
A. the servo gain setting is too large. It is recommended to readjust the servo parameters manually or automatically;
B. confirm the setting of time constant of speed feedback filter, the initial value is 0, and try to increase the setting value;
C. the electronic gear ratio is too large, it is recommended to restore to the factory setting;
D. resonance of servo system and mechanical system, try to adjust the frequency and amplitude of notch filter.
3. Mechanical system:
A. the coupling connecting the motor shaft and the equipment system is deviated, and the mounting screws are not tightened;
B. the poor engagement of pulley or gear will also cause the load torque change, and try to operate without load. If the operation is normal without load, check whether the joint part of mechanical system is abnormal;
c. Confirm whether the load inertia, torque and speed are too large. Try to operate without load. If the no-load operation is normal, reduce the load or replace the driver and motor with larger capacity.
Third.
Servo motor jitter is caused by mechanical structure, speed loop, compensation board of servo system, servo amplifier, load inertia, electrical part and other faults.
1. Vibration caused by mechanical structure can be divided into three situations:
1) No load jitter:
a. The motor foundation is not firm, the rigidity is not enough or the fixation is not tight.
b. The fan blade is damaged, which destroys the mechanical balance of the rotor.
c. The shaft is bent or cracked. It can be solved by fastening screws, replacing fan blades, replacing shafts, etc.
2) If the vibration is caused by the fault of the transmission device after the load is added, it can be judged that the following parts are defective:
a. Unbalanced rotation of belt pulley or coupling.
b. The center line of the coupling is inconsistent, so that the motor and the mechanical axis of the drive are not coincident.
c. Unbalanced drive belt joint. It can be solved by adjusting the driving device to make it balanced.
2. Jitter caused by speed loop problem:The parameters such as integral gain, proportional gain and acceleration feedback gain of velocity loop are improper. The larger the gain, the greater the speed, the greater the inertia force, the smaller the deviation, and the more prone to jitter. Setting a small gain can maintain the speed response and is not easy to generate jitter.
3. Jitter caused by fault of compensation board and servo amplifier of servo system: During the motor movement, the sudden power failure and stop cause great jitter, which is related to the BRK terminal of servo amplifier and improper setting parameters. The acceleration and deceleration time constant can be increased, and PLC can be used to start or stop the motor slowly so that it does not shake.
4. Jitter caused by load inertia:The problems of guide rail and screw lead to the increase of load inertia. The moment of inertia of guide rail and lead screw has a great influence on the rigidity of servo motor drive system. Under the fixed gain, the greater the moment of inertia, the greater the rigidity, the more likely to cause motor jitter; the smaller the moment of inertia, the smaller the rigidity, the less likely the motor jitter. It can reduce the moment of inertia of the load by replacing the guide rail and the screw rod with smaller diameter, so that the motor does not shake.
5. Jitter caused by electrical part:
a. The brake is not opened, and the feedback voltage is unstable. Check whether the brake is turned on. Add the zero servo function of encoder vector control, and output a certain torque in the way of torque reduction to solve the jitter. If the feedback voltage is abnormal, first check whether the vibration period is related to the speed. If it is related, check whether the connection between the main shaft and the main shaft motor is faulty, and whether the main shaft and the pulse generator installed at the end of the AC main shaft motor are damaged. If not, check whether the printed circuit board is faulty. Check the circuit board or readjust it.
b. When the motor suddenly vibrates during operation, most of which are caused by phase loss, it is important to check whether the fuse melt is fused, whether the switch contacts well, and whether each phase of the power grid has power.
Key words: servo motor jitter | servo motor overload | servo motor fault | servo motor maintenance | servo motor fault maintenance|
Post time: Mar-04-2020