How to Eliminate Vibration of A6 Servo Motor?
For servo motors, smooth operation is crucial. When you get a new motor, if you don't adjust the relevant gain parameters, the device may inevitably vibrate. So how can you reduce or even eliminate the vibration of the motor? Here we have prepared the following three methods for you:
Adjusting inertia ratio and rigidity
The load inertia ratio refers to the ratio of the total moment of inertia of the motor load to the motor's own moment of inertia. This parameter is an important parameter of the servo system. Correctly setting the load inertia ratio helps to quickly complete the commissioning. Usually the load inertia ratio (C00.06) can be set manually, which can be calculated based on the weight and composition of each part of the machine, but the operation is very cumbersome. The more complex the mechanical system, the more difficult it is to correctly solve the load inertia ratio. The A6 series servo motors of STEPPERONLINE have an automatic inertia identification function, which can be automatically identified through (F30.10) without the need for complex manual calculations.
As shown in the figure above, during the identification process, the driver will drive the servo motor in the forward or reverse direction for multiple times to obtain the load inertia ratio.
After the inertia adjustment is completed, let's set the rigidity:
The higher the rigidity level of the servo system, the stronger the gain and the faster the response, but too strong rigidity will cause vibration. Level 0 is the weakest rigidity and level 31 is the strongest. It is recommended that you reduce or increase the rigidity appropriately according to the actual situation.
Using the drive's self-tuning feature
A6 servo drive has three gain self-adjustment modes:
0- manual mode;
1- standard mode;
2- positioning mode.
When the automatic gain adjustment does not achieve the expected effect, you can manually fine-tune the gain. Through more detailed adjustments, the effect can be optimized.
Let's explain the following gain parameters:
C01.00: Position loop gain
The higher the position loop gain setting, the higher the responsiveness and the shorter the positioning time. Generally speaking, the position loop gain cannot be increased beyond the range of the mechanical system's natural vibration number.
To ensure system stability, the speed loop gain frequency (Hz) should be 3~5 times the position loop gain frequency (Hz).
C01.01: Speed loop gain
When the speed loop has low responsiveness, it will become a delay factor of the outer position loop, so overshoot or vibration of the speed command will occur. Therefore, within the range where the mechanical system does not vibrate, the larger the set value, the more stable the servo system and the better the responsiveness.
C01.03: Torque command filter cut-off frequency
This parameter is used to low-pass filter the torque command. The set value is the cutoff frequency of the low-pass filter. The smaller the set value, the better the filtering effect. A set value that is too small will cause the speed loop to delay too much, thereby reducing the speed loop bandwidth.
When the machine vibrates, it is possible to eliminate the vibration by appropriately reducing the parameter value.
Using the drive's vibration suppression function
The A6 driver has 5 sets of notches, each set of notches has 3 parameters, namely notch frequency, width level and depth level. The first and second sets of notches can be set manually or configured as adaptive notches (C01.30=1 or 2). In this case, the parameters are automatically set by the driver, and the other three sets can be set manually. The notch filter can suppress mechanical resonance by reducing the gain at a specific frequency. After the notch filter is set correctly, the vibration can be effectively suppressed, and you can try to continue to increase the servo gain.
Adaptive notch filter usage steps:
Set C01.30 (adaptive notch filter mode selection) to 1 or 2 according to the number of resonance points;
When resonance occurs, set C01.30 to 1 first to start an adaptive notch filter. After the gain is adjusted, if a new resonance occurs, set C01.30 to 2 to start two adaptive notches. When the servo is running, the parameters of the first or second set of notches will be automatically updated.
If the resonance is suppressed, it means that the adaptive notch filter has achieved results. If the resonance is still not eliminated, you can use the background tool to observe the waveform of the relevant variables and use the remaining three sets of notches to suppress the resonance.
The above is an effective method for eliminating vibration of A6 servo motors. For more details, please refer to the manual:
A6-RS Manual Chapter 6:
https://www.omc-stepperonline.com/index.php?route=product/product/get_file&file=5101/A6-RS%20series%20servo%20drive%20manual.pdf
A6-EC Manual Chapter 7:
https://www.omc-stepperonline.com/index.php?route=product/product/get_file&file=5071/A6-EC%20series%20servo%20drive%20manual.pdf
A6-PN Manual Chapter 6:
https://www.omc-stepperonline.com/index.php?route=product/product/get_file&file=5088/A6-PN%20series%20servo%20drive%20user%20manual.pdf
If you have any further questions, please feel free to contact us!
Adjusting inertia ratio and rigidity
The load inertia ratio refers to the ratio of the total moment of inertia of the motor load to the motor's own moment of inertia. This parameter is an important parameter of the servo system. Correctly setting the load inertia ratio helps to quickly complete the commissioning. Usually the load inertia ratio (C00.06) can be set manually, which can be calculated based on the weight and composition of each part of the machine, but the operation is very cumbersome. The more complex the mechanical system, the more difficult it is to correctly solve the load inertia ratio. The A6 series servo motors of STEPPERONLINE have an automatic inertia identification function, which can be automatically identified through (F30.10) without the need for complex manual calculations.
As shown in the figure above, during the identification process, the driver will drive the servo motor in the forward or reverse direction for multiple times to obtain the load inertia ratio.
After the inertia adjustment is completed, let's set the rigidity:
The higher the rigidity level of the servo system, the stronger the gain and the faster the response, but too strong rigidity will cause vibration. Level 0 is the weakest rigidity and level 31 is the strongest. It is recommended that you reduce or increase the rigidity appropriately according to the actual situation.
Using the drive's self-tuning feature
A6 servo drive has three gain self-adjustment modes:
0- manual mode;
1- standard mode;
2- positioning mode.
When the automatic gain adjustment does not achieve the expected effect, you can manually fine-tune the gain. Through more detailed adjustments, the effect can be optimized.
Let's explain the following gain parameters:
C01.00: Position loop gain
The higher the position loop gain setting, the higher the responsiveness and the shorter the positioning time. Generally speaking, the position loop gain cannot be increased beyond the range of the mechanical system's natural vibration number.
To ensure system stability, the speed loop gain frequency (Hz) should be 3~5 times the position loop gain frequency (Hz).
C01.01: Speed loop gain
When the speed loop has low responsiveness, it will become a delay factor of the outer position loop, so overshoot or vibration of the speed command will occur. Therefore, within the range where the mechanical system does not vibrate, the larger the set value, the more stable the servo system and the better the responsiveness.
C01.03: Torque command filter cut-off frequency
This parameter is used to low-pass filter the torque command. The set value is the cutoff frequency of the low-pass filter. The smaller the set value, the better the filtering effect. A set value that is too small will cause the speed loop to delay too much, thereby reducing the speed loop bandwidth.
When the machine vibrates, it is possible to eliminate the vibration by appropriately reducing the parameter value.
Using the drive's vibration suppression function
The A6 driver has 5 sets of notches, each set of notches has 3 parameters, namely notch frequency, width level and depth level. The first and second sets of notches can be set manually or configured as adaptive notches (C01.30=1 or 2). In this case, the parameters are automatically set by the driver, and the other three sets can be set manually. The notch filter can suppress mechanical resonance by reducing the gain at a specific frequency. After the notch filter is set correctly, the vibration can be effectively suppressed, and you can try to continue to increase the servo gain.
Adaptive notch filter usage steps:
Set C01.30 (adaptive notch filter mode selection) to 1 or 2 according to the number of resonance points;
When resonance occurs, set C01.30 to 1 first to start an adaptive notch filter. After the gain is adjusted, if a new resonance occurs, set C01.30 to 2 to start two adaptive notches. When the servo is running, the parameters of the first or second set of notches will be automatically updated.
If the resonance is suppressed, it means that the adaptive notch filter has achieved results. If the resonance is still not eliminated, you can use the background tool to observe the waveform of the relevant variables and use the remaining three sets of notches to suppress the resonance.
The above is an effective method for eliminating vibration of A6 servo motors. For more details, please refer to the manual:
A6-RS Manual Chapter 6:
https://www.omc-stepperonline.com/index.php?route=product/product/get_file&file=5101/A6-RS%20series%20servo%20drive%20manual.pdf
A6-EC Manual Chapter 7:
https://www.omc-stepperonline.com/index.php?route=product/product/get_file&file=5071/A6-EC%20series%20servo%20drive%20manual.pdf
A6-PN Manual Chapter 6:
https://www.omc-stepperonline.com/index.php?route=product/product/get_file&file=5088/A6-PN%20series%20servo%20drive%20user%20manual.pdf
If you have any further questions, please feel free to contact us!
Updated on: 11/02/2025
Thank you!