What is the cause of servo motor vibration?

Viewpoint 1
When the servo motor shakes at zero speed, it should be because the gain is set high, which can reduce the gain value. If there is a slight shaking during startup, the alarm will stop, and it is most likely due to incorrect motor phase sequence.

Viewpoint 2
1. When the PID gain adjustment is too large, it is easy to cause motor vibration, especially with the addition of D, which is particularly serious. Therefore, try to increase P and reduce I as much as possible, and it is best not to add D.
2. Even if the encoder wiring is connected incorrectly, there may be shaking.
3. Excessive load inertia, replace with larger motors and drivers.
4. Analog input interference causes jitter, and a magnetic ring is added to the motor input line and servo drive power input line to keep the signal line away from the power line.
5. There is also a type of rotary encoder interface motor, which can easily cause vibration due to poor grounding.

Viewpoint 3
① Servo wiring:
a. Use standard power cables, encoder cables, control cables, and check for any damage to the cables;
b. Check if there are any interference sources near the control line, and if they are parallel or too close to the nearby high current power cables;
c. Check if there is any change in the potential of the grounding terminal to ensure good grounding.
② Servo parameters:
a. The servo gain setting is too large, it is recommended to manually or automatically readjust the servo parameters;
b. Confirm the setting of the time constant for the speed feedback filter, with an initial value of 0. Attempt to increase the set value;
c. The electronic gear ratio is set too high, it is recommended to restore it to the factory settings;
d. Resonance between servo system and mechanical system, attempting to adjust harmonic filter frequency and amplitude.
③ Mechanical system:
a. The coupling connecting the motor shaft and the equipment system is offset, and the installation screws are not tightened;
b. Poor engagement of pulleys or gears can also cause changes in load torque. Try running without load, and if it runs normally without load, check if there are any abnormalities in the bonding part of the mechanical system;
c. Confirm if the load inertia, torque, and speed are too high, try running without load. If the no-load operation is normal, reduce the load or replace the driver and motor with a larger capacity.

Viewpoint 4
Servo motor jitter is caused by mechanical structure, speed loop, compensation plate and servo amplifier of servo system, load inertia, electrical faults, etc.

summary
1、 The shaking caused by mechanical structure can be divided into two situations:
1) Idle vibration:
a. The foundation of the electric motor is not strong enough, the stiffness is not sufficient, or it is not fixed tightly.
b. The fan blades are damaged, disrupting the mechanical balance of the rotor.
c. The shaft is bent or cracked. It can be solved by tightening screws, replacing fan blades, replacing machine shafts, and other methods.
2) If there is shaking after adding load, it is generally caused by a malfunction of the transmission device, and it can be determined that there are defects in the following parts:
a. The tape wheel or coupling rotates unevenly.
b. The centerline of the coupling is inconsistent, causing the motor to not coincide with the mechanical axis being driven.
c. The transmission tape joint is unbalanced. It can be solved by adjusting the transmission device to balance it.

2、 Vibration caused by speed loop issues:
Improper parameters such as speed loop integral gain, speed loop proportional gain, and acceleration feedback gain. The greater the gain, the faster the speed, the greater the inertial force, the smaller the deviation, and the more likely it is to produce jitter. Setting a smaller gain can maintain speed response and is less prone to jitter.

3、 Vibration caused by faults in the compensation board and servo amplifier of the servo system:
The sudden power failure and stop during motor movement result in significant shaking, which is related to improper connection terminals and parameter settings of the servo amplifier BRK. The acceleration and deceleration time constant can be increased, and the PLC can slowly start or stop the motor to prevent it from shaking.

4、 Vibration caused by load inertia:
Problems with the guide rail and screw lead cause an increase in load inertia. The rotational inertia of the guide rail and screw has a significant impact on the rigidity of the servo motor transmission system. Under fixed gain, the larger the rotational inertia, the greater the rigidity, and the more likely it is to cause motor vibration; The smaller the moment of inertia and rigidity, the less likely the motor is to shake. The motor can be stabilized by replacing smaller diameter guide rails and screw rods to reduce the rotational inertia and load inertia.

5、 Vibration caused by electrical components:
a. Caused by factors such as brake failure to open and unstable feedback voltage. Check if the brake is turned on, and use an encoder vector to control the zero servo function. Use a torque reduction method to output a certain amount of torque to solve the vibration. If the feedback voltage is abnormal, first check whether the vibration cycle is related to the speed. If it is related, check whether there is a fault in the connection between the spindle and the spindle motor, whether the spindle and the pulse generator installed at the end of the AC spindle motor are damaged, etc. If it is not related, check whether there is a fault on the printed circuit board. It is necessary to check the circuit board or readjust it.
b. Sudden shaking of the motor during operation is mostly caused by phase loss. It is important to check whether the fuse melt has melted, whether the switch contact is good, and measure whether there is electricity in each phase of the power grid.