Under what conditions will the servo motor shake? How can problems caused by servo motor jitter be solved? What are the solutions?
For example, if the acceleration and deceleration time is set too small, the servo motor will produce high inertia jitter when it is started or stopped suddenly.
Increasing the acceleration and deceleration time can solve this problem.
The following is an analysis of the causes of servo motor shaking by netizens for your reference.
Point of view 1
When the servo motor swings at zero speed, the gain must be adjusted downward to reduce the gain value.
If the alarm stops when the engine starts, the most likely reason is that the engine phase sequence is incorrect.
Point of view 2
The following are some reasons why servo motors may become unstable and suggestions on how to resolve the problems:
- If the servo motor shakes at zero speed, try reducing the gain value by setting the gain high.
- If the engine phase sequence is not correct, the alarm may stop when the engine starts.
- Setting the PID gain too high, especially after adding D, can cause motor instability. In this case, try increasing P and reducing I, avoiding adding D.
- Instability can also occur if the encoder is incorrectly connected.
- If the load inertia is too great, consider replacing the motor and driver with a larger one.
- Disturbance of the analog input port can cause instability, and adding a magnetic ring to the motor input line and servo driver power input line can help keep the signal line away from the power line.
- Poor grounding of the rotary encoder interface motor can also cause vibration.
Point of view 3
① Servo wiring:
- Use standard power cord, encoder cable, control cable and check whether the cable is damaged;
- Check whether there is a source of interference near the control line, whether it is parallel to or very close to the nearby high-current power cable;
- Check for any change in potential at the ground terminal to ensure good grounding.
②Servo parameters:
- The servo gain setting is too large, so it is recommended to adjust the servo parameters manually or automatically;
- Confirm the speed feedback filter time constant setting. The initial value is 0. Try increasing the setting value;
- The electronic gear ratio setting is too large, so it is recommended to return to the factory setting;
- Try adjusting the frequency and amplitude of the harmonic filter.
③ Mechanical system:
- The coupling connecting the motor shaft and the equipment system is displaced and the mounting screw is not tightened;
- Poor pulley or gear engagement will also lead to load torque variation. Try running without a load. If it is normal during no-load operation, check whether the joint part of the mechanical system is abnormal;
- Confirm whether the inertia, torque and speed of the load are too large and try running without load. If no-load operation is normal, reduce the load or replace the driver and motor with larger capacity.
Point of view 4
The jitter of the servo motor is caused by the mechanical structure, speed circuit, compensation board and servo amplifier of the servo system, load inertia, electrical part, etc.
S summary
1 . The vibration caused by the mechanical structure can be divided into two cases
1) No load instability:
- The motor base is not firm, the rigidity is not sufficient or the mounting is not watertight.
- The fan blade is damaged, which destroys the mechanical balance of the rotor.
- The shaft is bent or cracked. It can be solved by tightening the screw, replacing the fan blade and shaft.
2) If vibration occurs after charging, it is generally caused by the failure of the transmission device.
It can be assessed that there are defects in the following parts:
- The rotation of the belt pulley or coupling is unbalanced.
- The center line of the coupling is inconsistent, so the motor and mechanical shaft do not coincide.
- The drive belt joint is out of balance. This can be resolved by adjusting the transmission device to balance it.
two . Jitter caused by speed loop issue
The integral gain, proportional gain, and acceleration feedback gain of the speed loop may be inadequate.
The greater the gain, the greater the speed, the greater the inertial force, and the smaller the deviation, making jitter more likely to occur.
Setting a small gain can maintain speed response and is less likely to cause instability.
3 . Jitter caused by failure of the servo system compensation board and servo amplifier
When the engine stops suddenly during movement, it can cause significant instability. This usually occurs due to improper connection of the BRK terminal or parameter settings on the servo amplifier.
To reduce jitter, the acceleration and deceleration time constant can be increased. Alternatively, the engine can be started or stopped more slowly using the PLC.
4 . Jitter caused by load inertia
The problem with the guide rail and screw may cause an increase in load inertia.
The moment of inertia of the guide rail and lead screw has a great influence on the rigidity of the servo motor drive system.
Under fixed gain, a greater moment of inertia leads to greater stiffness and a greater probability of motor jitter.
On the other hand, a lower moment of inertia leads to reduced stiffness and a lower likelihood of motor jitter.
To reduce the load inertia and avoid engine oscillations, one solution is to change the guide rail and screw to a smaller diameter, which will reduce the moment of inertia.
5 . Jitter caused by the electrical part
The brake is not disengaged, causing the feedback voltage to be unstable.
Check that the brake is engaged and try using the encoder vector control to generate a certain torque, reducing the torque to resolve the jitter.
If the feedback voltage is abnormal, check whether the vibration period is related to speed.
If so, check whether the connection between the spindle and the spindle motor is defective or whether the spindle and the pulse generator installed on the tail of the AC spindle motor are damaged.
If it is not related to speed, check the printed circuit board for any faults and check or readjust the circuit board.
Sudden motor instability during operation is mainly caused by phase failure. Check if the fuse has melted, if the switch contacts are good and if each phase of the electrical network has power.
Final thoughts
After reading the analysis provided by these netizens, do you have a general understanding of what can cause servo motor instability?
If you encounter this problem, you can investigate the possible causes suggested by Internet users.
Additionally, it is important to be aware of these issues and take measures to prevent servo motor vibration.
