07 Adjustments

= **Overview** =

The servo drive needs to make the motor faithfully operate in accordance with the instructions issued by the upper controller without delay as much as possible. In order to make the motor action closer to the instruction and maximize the mechanical performance, gain adjustment is required. The process of gain adjustment is shown in Figure 7-1.

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[[**Figure 7-1 Gain adjustment process**>>image:image-20220608174118-1.png||id="Iimage-20220608174118-1.png"]]

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The servo gain is composed of multiple sets of parameters such as position loop, speed loop, filter, load inertia ratio, etc., and they affect each other. In the process of setting the servo gain, the balance between the setting values of each parameter must be considered.

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✎**Note: **Before adjusting the gain, it is recommended to perform a jog trial run first to ensure that the servo motor can operate normally! The gain adjustment process description is shown in the table below.

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(% class="table-bordered" style="margin-right:auto" %)

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|=(% colspan="3" style="text-align: center; vertical-align: middle;" %)**Gain adjustment process**|=(% style="text-align: center; vertical-align: middle;" %)**Function**|=(% style="text-align: center; vertical-align: middle;" %)**Detailed chapter**

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|(% style="text-align:center; vertical-align:middle" %)1|(% colspan="2" style="text-align:center; vertical-align:middle" %)Online inertia recognition|(% style="text-align:center; vertical-align:middle" %)Use the host computer debugging platform software matched with the drive to automatically identify the load inertia ratio. With its own inertia identification function, the drive automatically calculates the load inertia ratio.|(% style="text-align:center; vertical-align:middle" %)__[[7.2>>||anchor="HInertiarecognition"]]__

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|(% style="text-align:center; vertical-align:middle" %)2|(% colspan="2" style="text-align:center; vertical-align:middle" %)Automatic gain adjustment|On the premise of setting the inertia ratio correctly, the drive automatically adjusts a set of matching gain parameters.|(% style="text-align:center; vertical-align:middle" %)__[[7.3.1>>||anchor="HAutomaticgainadjustment"]]__

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|(% rowspan="2" style="text-align:center; vertical-align:middle" %)3|(% rowspan="2" style="text-align:center; vertical-align:middle" %)Manual gain adjustment|(% style="text-align:center; vertical-align:middle" %)Basic gain|On the basis of automatic gain adjustment, if the expected effect is not achieved, manually fine-tune the gain to optimize the effect.|(% style="text-align:center; vertical-align:middle" %)__[[7.3.2>>||anchor="HManualgainadjustment"]]__

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|(% style="text-align:center; vertical-align:middle" %)Feedforward gain|The feedforward function is enabled to improve the followability.|(% style="text-align:center; vertical-align:middle" %)__[[7.3.3>>||anchor="HFeedforwardgain"]]__

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|(% style="text-align:center; vertical-align:middle" %)4|(% style="text-align:center; vertical-align:middle" %)Vibration suppression|(% style="text-align:center; vertical-align:middle" %)Mechanical resonance|The notch filter function is enabled to suppress mechanical resonance.|(% style="text-align:center; vertical-align:middle" %)__[[7.4.1>>||anchor="HMechanicalresonancesuppressionmethods"]]__

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Table 7-1 Description of gain adjustment process

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= **Inertia recognition** =

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Load inertia ratio P03-01 refers to:

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[[image:image-20220611152902-1.png||class="img-thumbnail"]]

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The load inertia ratio is an important parameter of the servo system, and setting of the load inertia ratio correctly helps to quickly complete the debugging. The load inertia ratio could be set manually, and online load inertia recognition could be performed through the host computer debugging software.

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[[image:image-20220611152918-2.png]]

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**Before performing online load inertia recognition, the following conditions should be met:**

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* The maximum speed of the motor should be greater than 300rpm;

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* The actual load inertia ratio is between 0.00 and 100.00;

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* The load torque is relatively stable, and the load cannot change drastically during the measurement process;

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* The backlash of the load transmission mechanism is within a certain range;

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**The motor's runable stroke should meet two requirements:**

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* There is a movable stroke of more than 1 turn in both forward and reverse directions between the mechanical limit switches.

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* Before performing online inertia recognition, please make sure that the limit switch has been installed on the machine, and that the motor has a movable stroke of more than 1 turn each in the forward and reverse directions to prevent overtravel during the inertia recognition process and cause accidents.

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* Meet the requirement of inertia recognition turns P03-05.

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* Make sure that the motor's runable stroke at the stop position is greater than the set value of the number of inertia recognition circles P03-05, otherwise the maximum speed of inertia recognition P03-06 should be appropriately reduced.

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* During the automatic load inertia recognition process, if vibration occurs, the load inertia recognition should be stopped immediately.

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The related function codes are shown in the table below.

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|=(% scope="row" style="text-align: center; vertical-align: middle; width: 117px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 136px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 173px;" %)(((

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**Setting method**

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)))|=(% style="text-align: center; vertical-align: middle; width: 168px;" %)(((

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**Effective time**

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)))|=(% style="text-align: center; vertical-align: middle; width: 125px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 118px;" %)**Range**|=(% style="text-align: center; vertical-align: middle; width: 276px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle;" %)**Unit**

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|=(% style="text-align: center; vertical-align: middle; width: 117px;" %)P03-01|(% style="text-align:center; vertical-align:middle; width:136px" %)Load inertia ratio|(% style="text-align:center; vertical-align:middle; width:173px" %)(((

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Operation setting

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)))|(% style="text-align:center; vertical-align:middle; width:168px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:125px" %)300|(% style="text-align:center; vertical-align:middle; width:118px" %)100 to 10000|(% style="width:276px" %)Set load inertia ratio, 0.00 to 100.00 times|(% style="text-align:center; vertical-align:middle" %)0.01

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|=(% style="text-align: center; vertical-align: middle; width: 117px;" %)P03-05|(% style="text-align:center; vertical-align:middle; width:136px" %)(((

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Inertia recognition turns

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Shutdown setting

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)))|(% style="text-align:center; vertical-align:middle; width:168px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:125px" %)2|(% style="text-align:center; vertical-align:middle; width:118px" %)1 to 20|(% style="width:276px" %)Offline load inertia recognition process, motor rotation number setting|(% style="text-align:center; vertical-align:middle" %)circle

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|=(% style="text-align: center; vertical-align: middle; width: 117px;" %)P03-06|(% style="text-align:center; vertical-align:middle; width:136px" %)(((

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Inertia recognition maximum speed

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)))|(% style="text-align:center; vertical-align:middle; width:173px" %)(((

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Shutdown setting

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)))|(% style="text-align:center; vertical-align:middle; width:168px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:125px" %)1000|(% style="text-align:center; vertical-align:middle; width:118px" %)300 to 2000|(% style="width:276px" %)(((

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Set the allowable maximum motor speed instruction in offline inertia recognition mode.

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The faster the speed during inertia recognition, the more accurate the recognition result will be. Usually, you can keep the default value.

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)))|(% style="text-align:center; vertical-align:middle" %)rpm

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|=(% style="text-align: center; vertical-align: middle; width: 117px;" %)P03-07|(% style="text-align:center; vertical-align:middle; width:136px" %)(((

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Parameter recognition rotation direction

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Shutdown setting

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)))|(% style="text-align:center; vertical-align:middle; width:168px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:125px" %)0|(% style="text-align:center; vertical-align:middle; width:118px" %)0 to 2|(% style="width:276px" %)(((

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0: Forward and reverse reciprocating rotation

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1: Forward one-way rotation

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2: Reverse one-way rotation

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Table 7-2 Related parameters of gain adjustment

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= **Gain adjustment** =

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In order to optimize the responsiveness of the servo drive, the servo gain set in the servo drive needs to be adjusted. Servo gain needs to set multiple parameter combinations, which will affect each other. Therefore, the adjustment of servo gain must consider the relationship between each parameter.

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Under normal circumstances, high-rigidity machinery can improve the response performance by increasing the servo gain. But for machines with lower rigidity, when the servo gain is increased, vibration may occur, and then affects the increase in gain. Therefore, selecting appropriate servo gain parameters can achieve higher response and stable performance.

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The servo supports automatic gain adjustment and manual gain adjustment. It is recommended to use automatic gain adjustment first.

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== Automatic gain adjustment ==

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Automatic gain adjustment means that through the rigidity level selection function P03-02, the servo drive will automatically generate a set of matching gain parameters to meet the requirements of rapidity and stability.

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The rigidity of the servo refers to the ability of the motor rotor to resist load inertia, that is, the self-locking ability of the motor rotor. The stronger the servo rigidity, the larger the corresponding position loop gain and speed loop gain, and the faster the response speed of the system.

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(% class="warning" %)|(% style="text-align:center; vertical-align:middle" %)[[image:image-20220611152630-1.png]]

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|(% style="text-align:left; vertical-align:middle" %)Before adjusting the rigidity grade, set the appropriate load inertia ratio P03-01 correctly.

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The value range of the rigidity grade is between 0 and 31. Grade 0 corresponds to the weakest rigidity and minimum gain, and grade 31 corresponds to the strongest rigidity and maximum gain. According to different load types, the values in the table below are for reference.

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|=(% scope="row" style="text-align: center; vertical-align: middle;" %)**Rigidity grade**|=(% style="text-align: center; vertical-align: middle;" %)**Load mechanism type**

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|=(% style="text-align: center; vertical-align: middle;" %)Grade 4 to 8|(% style="text-align:center; vertical-align:middle" %)Some large machinery

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|=(% style="text-align: center; vertical-align: middle;" %)Grade 8 to 15|(% style="text-align:center; vertical-align:middle" %)Low rigidity applications such as belts

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|=(% style="text-align: center; vertical-align: middle;" %)Grade 15 to 20|(% style="text-align:center; vertical-align:middle" %)High rigidity applications such as ball screw and direct connection

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Table 7-3 Experience reference of rigidity grade

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When the function code P03-03 is set to 0, the gain parameters are stored in the first gain by modifying the rigidity grade.

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When debugging with the host computer debugging software, automatic rigidity level measurement can be carried out, which is used to select a set of appropriate rigidity grades as operating parameters. The operation steps are as follows:

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* Step1 Confirm that the servo is in the ready state, the panel displays “rdy”, and the communication line is connected;

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* Step2 Open the host computer debugging software, enter the trial run interface, set the corresponding parameters, and click "Servo on";

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* Step3 Click the "forward rotation" or "reverse rotation" button to confirm the travel range of the servo operation;

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* Step4 After the "start recognition" of inertia recognition lights up, click "start recognition" to perform inertia recognition, and the load inertia can be measured.

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* Step5 After the inertia recognition test is completed, click "Save Inertia Value";

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* Step6 Click "Next" at the bottom right to go to the parameter adjustment interface, and click "Parameter measurement" to start parameter measurement.

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* Step7 After the parameter measurement is completed, the host computer debugging software will pop up a confirmation window for parameter writing and saving.

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(% class="warning" %)|(% style="text-align:center; vertical-align:middle" %)[[image:image-20220611152634-2.png]]

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✎There may be a short mechanical whistling sound during the test. Generally, the servo will automatically stop the test. If it does not stop automatically or in other abnormal situations, you can click the "Servo Off" button on the interface to turn off the servo, or power off the machine!

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✎For the detailed operation of the host computer debugging software, please refer to "Wecon Servo Debugging Platform User Manual".

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|=(% scope="row" style="text-align: center; vertical-align: middle; width: 84px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 138px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 103px;" %)(((

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**Setting method**

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**Effective time**

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)))|=(% style="text-align: center; vertical-align: middle; width: 87px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 83px;" %)**Range**|=(% style="text-align: center; vertical-align: middle; width: 431px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle;" %)**Unit**

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|=(% style="text-align: center; vertical-align: middle; width: 84px;" %)P03-03|(% style="text-align:center; vertical-align:middle; width:138px" %)Self-adjusting mode selection|(% style="text-align:center; vertical-align:middle; width:103px" %)(((

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Operation setting

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)))|(% style="text-align:center; vertical-align:middle; width:105px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:87px" %)0|(% style="text-align:center; vertical-align:middle; width:83px" %)0 to 2|(% style="width:431px" %)(((

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* 0: Rigidity grade self-adjusting mode. Position loop gain, speed loop gain, speed loop integral time constant, torque filter parameter settings are automatically adjusted according to the rigidity grade setting.

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* 1: Manual setting; you need to manually set the position loop gain, speed loop gain, speed loop integral time constant, torque filter parameter setting

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* 2: Online automatic parameter self-adjusting mode (Not implemented yet)

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Table 7-4 Details of self-adjusting mode selection parameters

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== Manual gain adjustment ==

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When the servo automatic gain adjustment fails to achieve the desired result, you can manually fine-tune the gain to achieve better results.

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The servo system consists of three control loops, from the outside to the inside are the position loop, the speed loop and the current loop. The basic control block diagram is shown as below.

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[[**Figure 7-2 Basic block diagram of servo loop gain**>>image:image-20220608174209-2.png||id="Iimage-20220608174209-2.png"]]

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The more the inner loop is, the higher the responsiveness is required. Failure to comply with this principle may lead to system instability!

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The default current loop gain of the servo drive has ensured sufficient responsiveness. Generally, no adjustment is required. Only the position loop gain, speed loop gain and other auxiliary gains need to be adjusted.

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This servo drive has two sets of gain parameters for position loop and speed loop. The user can switch the two sets of gain parameters according to the setting value of P02-07 the 2nd gain switching mode. The parameters are below.

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|=(% scope="row" style="text-align: center; vertical-align: middle; width: 450px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 751px;" %)**Name**

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|=(% style="text-align: center; vertical-align: middle; width: 450px;" %)P02-01|(% style="width:751px" %)The 1st position loop gain

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|=(% style="text-align: center; vertical-align: middle; width: 450px;" %)P02-02|(% style="width:751px" %)The 1st speed loop gain

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|=(% style="text-align: center; vertical-align: middle; width: 450px;" %)P02-03|(% style="width:751px" %)The 1st speed loop integral time constant

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|=(% style="text-align: center; vertical-align: middle; width: 450px;" %)P02-04|(% style="width:751px" %)The 2nd position loop gain

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|=(% style="text-align: center; vertical-align: middle; width: 450px;" %)P02-05|(% style="width:751px" %)The 2nd speed loop gain

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|=(% style="text-align: center; vertical-align: middle; width: 450px;" %)P02-06|(% style="width:751px" %)The 2nd speed loop integral time constant

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|=(% style="text-align: center; vertical-align: middle; width: 450px;" %)P04-04|(% style="width:751px" %)Torque filter time constant

**Speed loop gain**

In the case of no vibration or noise in the mechanical system, the larger the speed loop gain setting value, the better the response of servo system and the better the speed followability. When noise occurs in the system, reduce the speed loop gain. The related function codes are shown as below.

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|=(% scope="row" style="text-align: center; vertical-align: middle; width: 120px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 163px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 122px;" %)(((

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**Setting method**

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)))|=(% style="text-align: center; vertical-align: middle; width: 128px;" %)(((

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**Effective time**

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)))|=(% style="text-align: center; vertical-align: middle; width: 103px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 107px;" %)**Range**|=(% style="text-align: center; vertical-align: middle; width: 321px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle;" %)**Unit**

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|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)P02-02|(% style="text-align:center; vertical-align:middle; width:163px" %)1st speed loop gain|(% style="text-align:center; vertical-align:middle; width:122px" %)(((

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Operation setting

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)))|(% style="text-align:center; vertical-align:middle; width:128px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:103px" %)65|(% style="text-align:center; vertical-align:middle; width:107px" %)0 to 35000|(% style="width:321px" %)Set speed loop proportional gain to determine the responsiveness of speed loop.|(% style="text-align:center; vertical-align:middle" %)0.1Hz

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|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)P02-05|(% style="text-align:center; vertical-align:middle; width:163px" %)2nd speed loop gain|(% style="text-align:center; vertical-align:middle; width:122px" %)(((

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Operation setting

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)))|(% style="text-align:center; vertical-align:middle; width:128px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:103px" %)65|(% style="text-align:center; vertical-align:middle; width:107px" %)0 to 35000|(% style="width:321px" %)Set speed loop proportional gain to determine the responsiveness of speed loop.|(% style="text-align:center; vertical-align:middle" %)0.1Hz

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Table 7-5 Speed loop gain parameters

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[[**Figure 7-3 Speed loop gain effect illustration**>>image:image-20220706152743-1.jpeg||id="Iimage-20220706152743-1.jpeg"]]

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**Speed loop integral time constant**

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The speed loop integral time constant is used to eliminate the speed loop deviation. Decreasing the integral time constant of the speed loop can increase the speed of the speed following. If the set value is too small, is will easily cause speed overshoot or vibration. When the time constant is set too large, the integral action will be weakened, resulting in a deviation of the speed loop. Related function codes are shown as below.

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|=(% scope="row" style="text-align: center; vertical-align: middle; width: 98px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 173px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 122px;" %)(((

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**Setting method**

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)))|=(% style="text-align: center; vertical-align: middle; width: 112px;" %)(((

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**Effective time**

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)))|=(% style="text-align: center; vertical-align: middle; width: 109px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 114px;" %)**Range**|=(% style="text-align: center; vertical-align: middle; width: 278px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle; width: 78px;" %)**Unit**

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|=(% style="text-align: center; vertical-align: middle; width: 98px;" %)P02-03|(% style="text-align:center; vertical-align:middle; width:173px" %)(((

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1st speed loop integral time constant

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)))|(% style="text-align:center; vertical-align:middle; width:122px" %)(((

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Operation setting

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)))|(% style="text-align:center; vertical-align:middle; width:112px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:109px" %)1000|(% style="text-align:center; vertical-align:middle; width:114px" %)100 to 65535|(% style="width:278px" %)Set the speed loop integral constant. The smaller the set value, the stronger the integral effect.|(% style="text-align:center; vertical-align:middle; width:78px" %)(((

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0.1ms

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|=(% style="text-align: center; vertical-align: middle; width: 98px;" %)P02-06|(% style="text-align:center; vertical-align:middle; width:173px" %)(((

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2nd speed loop integral time constant

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)))|(% style="text-align:center; vertical-align:middle; width:122px" %)(((

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Operation setting

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)))|(% style="text-align:center; vertical-align:middle; width:112px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:109px" %)1000|(% style="text-align:center; vertical-align:middle; width:114px" %)0 to 65535|(% style="width:278px" %)Set the speed loop integral constant. The smaller the set value, the stronger the integral effect.|(% style="text-align:center; vertical-align:middle; width:78px" %)(((

0.1ms

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Table 7-6 Speed loop integral time constant parameters

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[[**Figure 7-4 Speed loop integral time constant effect illustration**>>image:image-20220706153140-2.jpeg||id="Iimage-20220706153140-2.jpeg"]]

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**Position loop gain**

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Determine the highest frequency of the position instruction that the position loop can follow the change. Increasing this parameter can speed up the positioning time and improve the ability of the motor to resist external disturbances when the motor is stationary. However, if the setting value is too large, the system may be unstable and oscillate. The related function codes are shown as below.

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|=(% scope="row" style="text-align: center; vertical-align: middle; width: 95px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 174px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)(((

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**Setting method**

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)))|=(% style="text-align: center; vertical-align: middle; width: 114px;" %)(((

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**Effective time**

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)))|=(% style="text-align: center; vertical-align: middle; width: 79px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 91px;" %)**Range**|=(% style="text-align: center; vertical-align: middle; width: 355px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle;" %)**Unit**

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|=(% style="text-align: center; vertical-align: middle; width: 95px;" %)P02-01|(% style="text-align:center; vertical-align:middle; width:174px" %)1st position loop gain|(% style="text-align:center; vertical-align:middle; width:120px" %)(((

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Operation setting

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)))|(% style="text-align:center; vertical-align:middle; width:114px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:79px" %)400|(% style="text-align:center; vertical-align:middle; width:91px" %)0 to 6200|(% style="width:355px" %)Set position loop proportional gain to determine the responsiveness of position control system.|(% style="text-align:center; vertical-align:middle" %)0.1Hz

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|=(% style="text-align: center; vertical-align: middle; width: 95px;" %)P02-04|(% style="text-align:center; vertical-align:middle; width:174px" %)2nd position loop gain|(% style="text-align:center; vertical-align:middle; width:120px" %)(((

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Operation setting

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)))|(% style="text-align:center; vertical-align:middle; width:114px" %)(((

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Effective immediately

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)))|(% style="text-align:center; vertical-align:middle; width:79px" %)35|(% style="text-align:center; vertical-align:middle; width:91px" %)0 to 6200|(% style="width:355px" %)Set position loop proportional gain to determine the responsiveness of position control system.|(% style="text-align:center; vertical-align:middle" %)0.1Hz

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Table 7-7 Position loop gain parameters

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(% style="text-align:center" %)

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(% class="wikigeneratedid img-thumbnail" style="display:inline-block" %)

291

[[**Figure 7-5 Position loop gain effect illustration**>>image:image-20220706153656-3.jpeg||id="Iimage-20220706153656-3.jpeg"]]

292

)))

293

294

**Torque instruction filter time**

295

296

Selecting an appropriate torque filter time constant could suppress mechanical resonance. The larger the value of this parameter, the stronger the suppression ability. If the setting value is too large, it will decrease the current loop response frequency and cause needle movement. The related function codes are shown as below.

297

298

(% class="table-bordered" %)

299

|=(% scope="row" style="text-align: center; vertical-align: middle; width: 117px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 200px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)(((

300

**Setting method**

301

)))|=(% style="text-align: center; vertical-align: middle; width: 127px;" %)(((

302

**Effective time**

303

)))|=(% style="text-align: center; vertical-align: middle; width: 79px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 371px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle;" %)**Unit**

304

|=(% style="text-align: center; vertical-align: middle; width: 117px;" %)P04-04|(% style="text-align:center; vertical-align:middle; width:200px" %)Torque filter time constant|(% style="text-align:center; vertical-align:middle; width:120px" %)(((

305

Operation setting

306

)))|(% style="text-align:center; vertical-align:middle; width:127px" %)(((

307

Effective immediately

308

)))|(% style="text-align:center; vertical-align:middle; width:79px" %)50|(% style="width:371px" %)This parameter is automatically set when “self-adjustment mode selection” is selected as 1 or 2|(% style="text-align:center; vertical-align:middle" %)0.01ms

309

310

Table 7-8 Details of torque filter time constant parameters

311

312

== **Feedforward gain** ==

313

314

Speed feedforward could be used in position control mode and full closed-loop function. It could improve the response to the speed instruction and reduce the position deviation with fixed speed.

315

316

Speed feedforward parameters are shown in __Table 7-9__. Torque feedforward parameters are shown in __Table 7-10__.

317

318

Torque feedforward could improve the response to the torque instruction and reduce the position deviation with fixed acceleration and deceleration.

319

320

(% class="table-bordered" %)

321

|=(% scope="row" style="text-align: center; vertical-align: middle; width: 125px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 330px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 746px;" %)**Adjustment description**

322

|=(% style="text-align: center; vertical-align: middle; width: 125px;" %)P02-09|(% style="text-align:center; vertical-align:middle; width:330px" %)Speed feedforward gain|(% rowspan="2" style="width:746px" %)(((

323

When the speed feedforward filter is set to 50 (0.5 ms), gradually increase the speed feedforward gain, and the speed feedforward will take effect. The position deviation during operation at a certain speed will be reduced according to the value of speed feedforward gain as the formula below.

324

325

Position deviation (instruction unit) = instruction speed[instruction unit/s]÷position loop gain [1/s]×(100－speed feedforward gain [%])÷100

326

)))

327

|=(% style="text-align: center; vertical-align: middle; width: 125px;" %)P02-10|(% style="text-align:center; vertical-align:middle; width:330px" %)Speed feedforward filtering time constant

328

329

Table 7-9 Speed feedforward parameters

330

331

(% style="text-align:center" %)

332

(((

333

(% class="wikigeneratedid img-thumbnail" style="display:inline-block" %)

334

[[**Figure 7-6 Speed feedforward parameters effect illustration**>>image:image-20220706155307-4.jpeg||height="119" id="Iimage-20220706155307-4.jpeg" width="835"]]

)))

(% class="table-bordered" %)

339

|=(% scope="row" style="text-align: center; vertical-align: middle; width: 125px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 259px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 690px;" %)**Adjustment description**

340

|=(% style="text-align: center; vertical-align: middle; width: 125px;" %)P02-11|(% style="text-align:center; vertical-align:middle; width:259px" %)Torque feedforward gain|(% rowspan="2" style="width:690px" %)Increase the torque feedforward gain because the position deviation can be close to 0 during certain acceleration and deceleration. Under the ideal condition of external disturbance torque not operating, when driving in the trapezoidal speed model, the position deviation can be close to 0 in the entire action interval. In fact, there must be external disturbance torque, so the position deviation cannot be zero. In addition, like the speed feedforward, although the larger the constant of the torque feedforward filter, the smaller the action sound, but the greater the position deviation of the acceleration change point.

341

|=(% style="text-align: center; vertical-align: middle; width: 125px;" %)P02-12|(% style="text-align:center; vertical-align:middle; width:259px" %)Torque feedforward filtering time constant

342

343

Table 7-10 Torque feedforward parameters

344

345

== **Model Tracking Control Function** ==

346

347

Model tracking control is suitable for position control mode, which adds a model loop outside the three loops. In the model loop, new position commands, speed feedforward and torque feedforward and other control quantities are generated according to the user's response requirements to the system and the ideal motor control model. Applying these control quantities to the actual control loop can significantly improve the response performance and positioning performance of the position control, the design block diagram is as follows:

348

349

(% style="text-align:center" %)

350

(((

351

(% class="wikigeneratedid img-thumbnail" style="display:inline-block" %)

352

[[**Figure 7-7 Block Diagram of Model Tracking Control Design**>>image:20230515-7.png||height="394" id="20230515-7.png" width="931"]]

353

)))

354

355

The usage method and conditions of model tracking control:

356

357

~1. Correctly set the inertia ratio of the system P3-1, which can be obtained by monitoring the real-time load inertia ratio of U0-20.

358

359

2. Set the load rigidity level P3-2, set an appropriate value, it does not need to set a high rigidity level (recommended value 17~~21 under rigid load).

360

361

3. Set P2-20=1 to enable the function of model tracking control.

362

363

4. Adjust the P2-21 model tracking control gain from small to large, and gradually increase in steps of 1000 until the responsiveness of the system meets the actual demand. The responsiveness of the system is mainly determined by this parameter.

364

365

5. After the responsiveness meets the requirements, user can adjust the parameters appropriately to increase the load rigidity level P3-2.

366

367

(% class="box infomessage" %)

368

(((

369

**✎Note**: Model tracking control is only available in position mode, and cannot be used in other modes.

370

)))

371

372

(% class="table-bordered" %)

373

|=(% scope="row" style="text-align: center; vertical-align: middle; width: 120px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 163px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 122px;" %)(((

374

**Setting method**

375

)))|=(% style="text-align: center; vertical-align: middle; width: 128px;" %)(((

376

**Effective time**

377

)))|=(% style="text-align: center; vertical-align: middle; width: 103px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 107px;" %)**Range**|=(% style="text-align: center; vertical-align: middle; width: 321px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle;" %)**Unit**

378

|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)P2-20|(% style="text-align:center; vertical-align:middle; width:163px" %)Model tracking control function|(% style="text-align:center; vertical-align:middle; width:122px" %)(((

379

Shutdown setting

380

)))|(% style="text-align:center; vertical-align:middle; width:128px" %)(((

381

Effective immediately

382

)))|(% style="text-align:center; vertical-align:middle; width:103px" %)0|(% style="text-align:center; vertical-align:middle; width:107px" %)0 to 1|When the function code is set to 1, enable the model tracking control function.|

383

|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)P2-21|(% style="text-align:center; vertical-align:middle; width:163px" %)Model tracking control gain|(% style="text-align:center; vertical-align:middle; width:122px" %)(((

384

Shutdown setting

385

)))|(% style="text-align:center; vertical-align:middle; width:128px" %)(((

386

Effective immediately

387

)))|(% style="text-align:center; vertical-align:middle; width:103px" %)1000|(% style="text-align:center; vertical-align:middle; width:107px" %)200 to 20000|(% rowspan="2" style="width:321px" %)Increasing the model tracking control gain can improve the position response performance of the model loop. If the gain is too high, it may cause overshoot behavior. The gain compensation affects the damping ratio of the model loop, and the damping ratio becomes larger as the gain compensation becomes larger.|(% style="text-align:center; vertical-align:middle" %)0.1/s

388

|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)P2-22|(% style="text-align:center; vertical-align:middle; width:163px" %)Model tracking control gain compensation|(% style="text-align:center; vertical-align:middle; width:122px" %)(((

389

Shutdown setting

390

)))|(% style="text-align:center; vertical-align:middle; width:128px" %)(((

391

Effective immediately

392

)))|(% style="text-align:center; vertical-align:middle; width:103px" %)1000|(% style="text-align:center; vertical-align:middle; width:107px" %)500 to 2000|(% style="text-align:center; vertical-align:middle" %)0.10%

393

394

(% class="table-bordered" %)

395

|=(% scope="row" style="text-align: center; vertical-align: middle; width: 120px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 163px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 122px;" %)(((

396

**Setting method**

397

)))|=(% style="text-align: center; vertical-align: middle; width: 128px;" %)(((

398

**Effective time**

399

)))|=(% style="text-align: center; vertical-align: middle; width: 103px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 107px;" %)**Range**|=(% style="text-align: center; vertical-align: middle; width: 321px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle;" %)**Unit**

400

|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)P2-23|(% style="text-align:center; vertical-align:middle; width:163px" %)Model tracking control forward rotation bias|(((

401

Operation setting

402

)))|(% style="text-align:center; vertical-align:middle; width:128px" %)(((

403

Effective immediately

404

)))|(% style="text-align:center; vertical-align:middle; width:103px" %)1000|(% style="text-align:center; vertical-align:middle; width:107px" %)0 to 10000|(% rowspan="2" %)(% style="width:321px" %)Torque feedforward size in the positive and reverse direction under model tracking control|(% style="text-align:center; vertical-align:middle" %)0.10%

405

|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)P2-24|(% style="text-align:center; vertical-align:middle; width:163px" %)Model tracking control reverses rotation bias|(((

406

Operation setting

407

)))|(% style="text-align:center; vertical-align:middle; width:128px" %)(((

408

Effective immediately

409

)))|(% style="text-align:center; vertical-align:middle; width:103px" %)1000|(% style="text-align:center; vertical-align:middle; width:107px" %)0 to 10000|(% style="text-align:center; vertical-align:middle" %)0.10%

410

|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)P2-25|(% style="text-align:center; vertical-align:middle; width:163px" %)Model tracking control speed feedforward compensation|Operation setting|(% style="text-align:center; vertical-align:middle; width:128px" %)(((

411

Effective immediately

412

)))|(% style="text-align:center; vertical-align:middle; width:103px" %)1000|(% style="text-align:center; vertical-align:middle; width:107px" %)0 to 10000|(% style="width:321px" %)The size of the speed feedforward under model tracking control|(% style="text-align:center; vertical-align:middle" %)0.10%

413

414

Please refer to the following for an example of the procedure of adjusting servo gain.

415

416

(% style="width:1508px" %)

417

|=(% style="text-align:center; vertical-align:middle; width:80px" %)**Step**|=(% style="text-align:center; vertical-align:middle; width:1420px" %)**Content**

418

|=(% style="text-align: center; vertical-align: middle; width: 80px;" %)1|Please try to set the correct load inertia ratio parameter P3-1.

419

|=(% style="text-align:center; vertical-align:middle; width:80px" %)2|If the automatic adjustment mode is used (P3-3 is set to 0), please set the basic rigidity level parameter P3-2. If in manual adjustment mode (P3-3 is set to 1), please set the gain P2-1~~P2-3 related to the position loop and speed loop and the torque filter time constant P4-4. The setting principle is mainly no vibration and overshoot.

420

|=(% style="text-align: center; vertical-align: middle; width: 80px;" %)3|Turn on the model tracking function, set P2-20 to 1.

421

|=(% style="text-align: center; vertical-align: middle; width: 80px;" %)4|Increase the model tracking gain P2-21 within the range of no overshoot and vibration occurring.

422

|=(% style="text-align: center; vertical-align: middle; width: 80px;" %)5|If the rigidity level of step 2 is set relatively low, user can properly increase the rigidity level P3-2.

423

|=(% style="text-align: center; vertical-align: middle; width: 80px;" %)6|When overshoot occurs, or the responses of forward rotation and reverse rotation are different, user can fine-tune through model tracking control forward bias P2-23, model tracking control reverse bias P2-24, model tracking control speed feedforward compensation P2 -25.

424

425

== **Gain switching** ==

426

427

**Gain switching function:**

428

429

● Switch to a lower gain in the motor stationary (servo enabled)state to suppress vibration;

430

431

● Switch to a higher gain in the motor stationary state to shorten the positioning time;

432

433

● Switch to a higher gain in the motor running state to get better command tracking performance;

434

435

● Switch different gain settings by external signals depending on the load connected.

436

437

**Gain switching parameter setting**

①When P02-07=0

Fixed use of the first gain (using P02-01~~P02-03), and the switching of P/PI (proportional/proportional integral) control could be realized through DI function 10 (GAIN-SEL, gain switching).

442

443

(% style="text-align:center" %)

444

(((

445

(% class="wikigeneratedid img-thumbnail" style="display:inline-block" %)

446

[[image:20230515-8.png||height="378" id="20230515-8.png" width="363"]]

)))

② When P02-07=1

The switching conditions can be set through parameter P02-08 to realize switching between the first gain (P02-01~~P02-03) and the second gain (P02-04~~P02-06).

452

453

(% style="text-align:center" %)

454

(((

455

(% class="wikigeneratedid img-thumbnail" style="display:inline-block" %)

456

[[**Figure 7-9 Flow chart of gain switching when P02-07=1**>>image:20230515-9.png||id="20230515-9.png"]]

457

)))

458

459

|=(% style="text-align:center; vertical-align:middle; width:120px" %)**P02-08**|=(% style="text-align: center; vertical-align: middle; width: 464px;" %)**Content**|=(% style="text-align: center; vertical-align: middle; width: 946px;" %)**Diagram**

460

|=(% style="text-align:center; vertical-align:middle" %)0|(% style="text-align:center; vertical-align:middle; width:464px" %)Fixed use of the first gain|(% style="width:946px" %)~-~-

461

|=(% style="text-align:center; vertical-align:middle" %)1|(% style="text-align:center; vertical-align:middle; width:464px" %)Switching with DI|(% style="width:946px" %)~-~-

462

|=(% style="text-align:center; vertical-align:middle" %)(((

463

2

464

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)(((

465

Large torque command

466

)))|(% style="width:946px" %)[[image:image-20230515140641-1.png]]

467

|=(% style="text-align:center; vertical-align:middle" %)(((

468

3

469

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)Large actual torque|(% style="width:946px" %)[[image:image-20230515140641-2.png]]

470

|=(% style="text-align:center; vertical-align:middle" %)(((

471

4

472

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)(((

473

Large speed command

474

)))|(% style="width:946px" %)[[image:image-20230515140641-3.png]]

475

|=(% style="text-align:center; vertical-align:middle" %)(((

476

5

477

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)(((

478

Fast actual speed

479

)))|(% style="width:946px" %)(((

480

[[image:image-20230515140641-4.png]]

481

)))

482

|=(% style="text-align:center; vertical-align:middle" %)(((

483

6

484

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)(((

485

Speed command change rate is large

486

)))|(% style="width:946px" %)[[image:image-20230515140641-5.png]]

487

|=(% style="width:74px" %)(((

488

7

489

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)(((

490

Large position deviation

491

)))|(% style="width:946px" %)[[image:image-20230515140641-6.png]]

492

|=(% style="text-align:center; vertical-align:middle;" %)(((

493

8

494

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)(((

495

Position command

496

)))|(% style="width:946px" %)[[image:image-20230515140641-7.png]]

497

|=(% style="text-align:center; vertical-align:middle; width:74px" %)(((

498

9

499

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)(((

500

Positioning completed

501

)))|(% style="width:946px" %)[[image:image-20230515140641-8.png]]

502

|=(% style="text-align:center; vertical-align:middle" %)(((

503

10

504

)))|(% style="text-align:center; vertical-align:middle; width:464px" %)(((

505

Position command + actual speed

506

)))|(% style="text-align:center; vertical-align:middle; width:946px" %)(((

507

Refer to the chart below

508

)))

509

510

(% style="text-align:center" %)

511

(((

512

(% class="wikigeneratedid img-thumbnail" style="display:inline-block" %)

513

[[**Figure 7-10 P02-08=10 Position command + actual speed gain description**>>image:20230515-10.png||id="Iimage-20220608174118-1.png"]]

514

)))

515

516

**Description of related parameters**

517

518

|=(% rowspan="2" style="text-align: center; vertical-align: middle; width:120px" %)

519

**P02-07**|=(% style="width:150px" %)**Parameter name**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Setting method**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Effective time**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Default**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Set range**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Application category**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Unit**

520

|(% style="text-align:center; width:150px" %)The second gain switching mode|(% style="text-align:center" %)Operation setting|(% style="text-align:center" %)Effective immediately|(% style="text-align:center" %)0|(% style="text-align:center" %)0 to 1|(% style="text-align:center" %)Gain control|

521

|(% colspan="8" %)(((

522

Set the switching mode of the second gain.

523

524

|=(% style="text-align: center; vertical-align: middle; width:120px" %) **Setting value**|=(% style="text-align: center; vertical-align: middle" %)**Function**

525

|=(% style="text-align: center; vertical-align: middle" %)0|(((

526

The first gain is used by default. Switching using DI function 10 (GAIN-SEL, gain switching):

527

528

DI logic invalid: PI control;

529

530

DI logic valid: PI control.

531

)))

532

|=(% style="text-align: center; vertical-align: middle" %)1|The first gain and the second gain are switched by the setting value of P02-08.

533

)))

534

535

|=(% rowspan="2" style="text-align: center; vertical-align: middle; width:120px" %)**P02-08**|=(% style="width:150px" %)Parameter name|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Setting method**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Effective time**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Default**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Set range**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Application category**|=(% style="text-align: center; vertical-align: middle; width: 120px;" %)**Unit**

536

537

|(% colspan="8" %)(((

538

Set the conditions for gain switching.

539

540

|Setting value|Gain switching conditions|Details

541

|0|The default is the first gain|Fixed use of the first gain

542

|1|Switch by DI port|(((

543

Use DI function 10 (GAIN-SEL, gain switching);

544

545

DI logic is invalid: the first gain (P02-01~~P02-03);

546

547

DI logic is valid: the second gain (P02-04~~P02-06).

548

)))

549

|2|Large torque command|(((

550

In the previous first gain, when the absolute value of torque command is greater than (grade + hysteresis), the second gain is switched;

551

552

In the previous second gain, when the absolute value of torque command is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned.

)))

|3|Large actual torque|(((

557

In the previous first gain, when the absolute value of actual torque is greater than ( grade + hysteresis ), the second gain is switched;

558

559

In the previous second gain, when the absolute value of actual torque is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned.

)))

|4|Large speed command|(((

564

In the previous first gain, when the absolute value of speed command is greater than (grade + hysteresis), the second gain is switched;

565

566

In the previous second gain, when the absolute value of speed command is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

)))

|5|Large actual speed|(((

571

In the previous first gain, when the absolute value of actual speed is greater than (grade + hysteresis), the second gain is switched;

572

573

In the previous second gain, when the absolute value of actual speed is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

)))

|(((

6

)))|(((

Large rate of change in speed command

585

)))|(((

586

In the previous first gain, when the absolute value of the rate of change in speed command is greater than (grade + hysteresis), the second gain is switched;

587

588

In the previous second gain, switch to the first gain when the absolute value of the rate of change in speed command is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

)))

|(((

7

)))|(((

Large position deviation

600

)))|(((

601

In the previous first gain, when the absolute value of position deviation is greater than (grade + hysteresis), the second gain is switched;

602

603

In the previous second gain, switch to the first gain when the absolute value of position deviation is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

604

)))

605

|8|Position command|(((

606

In the previous first gain, if the position command is not 0, switch to the second gain;

607

608

In the previous second gain, if the position command is 0 and the duration is greater than [P02-13], the first gain is returned.

)))

|(((

9

)))|(((

Positioning complete

)))|(((

In the previous first gain, if the positioning is not completed, the second gain is switched; In the previous second gain, if the positioning is not completed and the duration is greater than [P02-13], the first gain is returned.

)))

|(((

10

)))|(((

Position command + actual speed

631

)))|(((

632

In the previous first gain, if the position command is not 0, the second gain is switched;

633

634

In the previous second gain, if the position command is 0, the duration is greater than [P02-13] and the absolute value of actual speed is less than ( grade - hysteresis).

)))

)))

|(% rowspan="2" %)

|Delay Time for Gain Switching|Operation setting|Effective immediately|20|0 to 10000|Gain control|0.1ms

645

|(% colspan="8" %)(((

646

The duration of the switching condition required for the second gain to switch back to the first gain.

647

648

[[image:image-20230515140953-9.png]]

649

650

**✎**Note: This parameter is only valid when the second gain is switched back to the first gain.

)))

|(% rowspan="2" %)

|(% colspan="8" %)(((

657

Set the grade of the gain condition. The generation of the actual switching action is affected by the two conditions of grade and hysteresis.

658

659

[[image:image-20230515140953-10.png]]

)))

|(% rowspan="2" %)

|(% colspan="8" %)(((

666

Set the hysteresis to meet the gain switching condition.

667

668

[[image:image-20230515140953-11.png]]

)))

|(% rowspan="2" %)

|Position loop gain switching time|Operation setting|Effective immediately|30|0 to 10000|Gain control|0.1ms

674

|(% colspan="8" %)(((

675

Set the time for switching from the first position loop (P02-01) to the second position loop (P02-04) in the position control mode.

676

677

[[image:image-20230515140953-12.png]]

678

679

If P02-04≤P02-01, then P02-16 is invalid, and the second gain is switched from the first gain immediately.

680

)))

681

682

== **Model Tracking Control Function** ==

683

684

Model tracking control is suitable for position control mode, which adds a model loop outside the three loop. In the model loop, new position commands, speed feedforward and torque feedforward and other control quantities are generated according to the user's response requirements to the system and the ideal motor control model. Applying these control quantities to the actual control loop can significantly improve the response performance and positioning performance of the position control, the design block diagram is as follows:

685

686

(% style="text-align:center" %)

687

[[image:20230515-7.png]]

688

689

The usage method and conditions of model tracking control:

690

691

~1. Correctly set the inertia ratio of the system P3-1, which can be obtained by monitoring the real-time load inertia ratio of U0-20.

692

693

2. Set the load rigidity level P3-2, set an appropriate value, it is not need to set a high rigidity level (recommended value 17~~21 under rigid load).

694

695

3. Set P2-20=1 to enable the function of model tracking control.

696

697

4. Adjust the P2-21 model tracking control gain from small to large, and gradually increase in steps of 1000 until the responsiveness of the system meets the actual demand. The responsiveness of the system is mainly determined by this parameter.

698

699

5. After the responsiveness meets the requirements, user can adjust the parameters appropriately to increase the load rigidity level P3-2.

700

701

**✎Note**: Model tracking control is only available in position mode, and cannot be used in other modes.

702

703

|**Function code**|**Name**|(((

**Setting**

**method**

)))|(((

**Effective**

**time**

)))|**Default**|**Range**|**Definition**|**Unit**

712

|P2-20|Model tracking control function|Shutdown setting|(((

Effective

immediately

)))|0|0 to 1|When the function code is set to 1, enable the model tracking control function.|

717

|P2-21|Model tracking control gain|Shutdown setting|(((

Effective

immediately

)))|1000|200 to 20000|(% rowspan="2" %)Increasing the model tracking control gain can improve the position response performance of the model loop. If the gain is too high, it may cause overshoot behavior. The gain compensation affects the damping ratio of the model loop, and the damping ratio becomes larger as the gain compensation becomes larger.|0.1/s

722

|P2-22|Model tracking control gain compensation|Shutdown setting|(((

Effective

immediately

)))|1000|500 to 2000|0.10%

727

728

|**Function code**|**Name**|(((

**Setting**

**method**

)))|(((

**Effective**

**time**

)))|**Default**|**Range**|**Definition**|**Unit**

737

|P2-23|Model tracking control forward rotation bias|(((

Operation

setting

)))|(((

Effective

immediately

)))|1000|0 to 10000|(% rowspan="2" %)Torque feedforward size in the positive and reverse direction under model tracking control|0.10%

746

|P2-24|Model tracking control reverses rotation bias|(((

Operation

setting

)))|(((

Effective

immediately

)))|1000|0 to 10000|0.10%

755

|P2-25|Model tracking control speed feedforward compensation|Operation setting|(((

Effective

immediately

)))|1000|0 to 10000|The size of the speed feedforward under model tracking control|0.10%

760

761

Please refer to the following for an example of the procedure of adjusting servo gain.

762

763

|**Step**|**Content**

764

|1|Please try to set the correct load inertia ratio parameter P3-1.

765

|2|If the automatic adjustment mode is used (P3-3 is set to 0), please set the basic rigidity level parameter P3-2. If in manual adjustment mode (P3-3 is set to 1), please set the gain P2-1~~P2-3 related to the position loop and speed loop and the torque filter time constant P4-4. The setting principle is mainly no vibration and overshoot.

766

|3|Turn on the model tracking function, set P2-20 to 1.

767

|4|Increase the model tracking gain P2-21 within the range of no overshoot and vibration occur.

768

|5|If the rigidity level of step 2 is set relatively low, user can properly increase the rigidity level P3-2.

769

|6|When overshoot occurs, or the responses of forward rotation and reverse rotation are different, user can fine-tune through model tracking control forward bias P2-23, model tracking control reverse bias P2-24, model tracking control speed feedforward compensation P2 -25.

770

771

== **Gain switching** ==

772

773

Gain switching function:

774

775

●Switch to a lower gain in the motor stationary (servo enabled)state to suppress vibration;

776

777

●Switch to a higher gain in the motor stationary state to shorten the positioning time;

778

779

●Switch to a higher gain in the motor running state to get better command tracking performance;

780

781

●Switch different gain settings by external signals depending on the load connected.

782

783

(1) Gain switching parameter setting

①When P02-07=0

Fixed use of the first gain (using P02-01~~P02-03), and the switching of P/PI (proportional/proportional integral) control could be realized through DI function 10 (GAIN-SEL, gain switching).

788

789

(% style="text-align:center" %)

790

[[image:20230515-8.png]]

② When P02-07=1

The switching conditions can be set through parameter P02-08 to realize switching between the first gain (P02-01~~P02-03) and the second gain (P02-04~~P02-06).

795

796

(% style="text-align:center" %)

797

[[image:20230515-9.png]]

798

799

Figure 7-9 Flow chart of gain switching when P02-07=1

800

801

|(% style="width:72px" %)**P02-08**|(% style="width:146px" %)**Content**|**Diagram**

802

|(% style="width:72px" %)0|(% style="width:146px" %)Fixed use of the first gain|~-~-

803

|(% style="width:72px" %)1|(% style="width:146px" %)Switching with DI|~-~-

804

|(% style="width:72px" %)(((

2

)))|(% style="width:146px" %)(((

Large torque command

)))|[[image:image-20230515140641-1.png]]

821

|(% style="width:72px" %)(((

3

)))|(% style="width:146px" %)Large actual torque|[[image:image-20230515140641-2.png]]

831

|(% style="width:72px" %)(((

4

)))|(% style="width:146px" %)(((

Large speed command

)))|[[image:image-20230515140641-3.png]]

848

849

|(% style="width:74px" %)**P02-08**|(% style="width:176px" %)**Content**|**Diagram**

850

|(% style="width:74px" %)(((

5

)))|(% style="width:176px" %)(((

Fast actual speed

)))|(((

[[image:image-20230515140641-4.png]]

868

)))

869

|(% style="width:74px" %)(((

6

)))|(% style="width:176px" %)(((

Speed command change rate is large

887

)))|[[image:image-20230515140641-5.png]]

888

|(% style="width:74px" %)(((

7

)))|(% style="width:176px" %)(((

Large position deviation

906

)))|[[image:image-20230515140641-6.png]]

907

|(% style="width:74px" %)(((

8

)))|(% style="width:176px" %)(((

Position command

)))|[[image:image-20230515140641-7.png]]

922

923

|(% style="width:73px" %)(((

9

)))|(% style="width:154px" %)(((

Positioning completed

939

)))|[[image:image-20230515140641-8.png]]

940

|(% style="width:73px" %)(((

10

)))|(% style="width:154px" %)(((

947

948

949

Position command + actual speed

)))|(((

Refer to the chart below

954

)))

955

956

(% style="text-align:center" %)

957

[[image:20230515-10.png]]

958

959

Figure 7-10 P02-08=10 Position command + actual speed gain description

960

961

(2) Description of related parameters

962

963

|(% rowspan="2" style="width:68px" %)

964

965

966

|(% colspan="8" %)(((

967

Set the switching mode of the second gain.

968

969

|**Setting value**|**Function**

970

|0|(((

971

The first gain is used by default. Switching using DI function 10 (GAIN-SEL, gain switching):

972

973

DI logic invalid: PI control;

974

975

DI logic valid: PI control.

976

)))

977

|1|The first gain and the second gain are switched by the setting value of P02-08.

)))

|(% rowspan="2" %)

|(% colspan="8" %)(((

984

Set the conditions for gain switching.

985

986

|Setting value|Gain switching conditions|Details

987

|0|The default is the first gain|Fixed use of the first gain

988

|1|Switch by DI port|(((

989

Use DI function 10 (GAIN-SEL, gain switching);

990

991

DI logic is invalid: the first gain (P02-01~~P02-03);

992

993

DI logic is valid: the second gain (P02-04~~P02-06).

994

)))

995

|2|Large torque command|(((

996

In the previous first gain, when the absolute value of torque command is greater than (grade + hysteresis), the second gain is switched;

997

998

In the previous second gain, when the absolute value of torque command is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned.

)))

|3|Large actual torque|(((

1003

In the previous first gain, when the absolute value of actual torque is greater than ( grade + hysteresis ), the second gain is switched;

1004

1005

In the previous second gain, when the absolute value of actual torque is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

)))

|4|Large speed command|(((

1010

In the previous first gain, when the absolute value of speed command is greater than (grade + hysteresis), the second gain is switched;

1011

1012

In the previous second gain, when the absolute value of speed command is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

)))

|5|Large actual speed|(((

1017

In the previous first gain, when the absolute value of actual speed is greater than (grade + hysteresis), the second gain is switched;

1018

1019

In the previous second gain, when the absolute value of actual speed is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

)))

|(((

6

)))|(((

Large rate of change in speed command

1031

)))|(((

1032

In the previous first gain, when the absolute value of the rate of change in speed command is greater than (grade + hysteresis), the second gain is switched;

1033

1034

In the previous second gain, switch to the first gain when the absolute value of the rate of change in speed command is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

)))

|(((

7

)))|(((

Large position deviation

1046

)))|(((

1047

In the previous first gain, when the absolute value of position deviation is greater than (grade + hysteresis), the second gain is switched;

1048

1049

In the previous second gain, switch to the first gain when the absolute value of position deviation is less than the value of (grade - hysteresis) and the duration is greater than [P02-13], the first gain is returned .

1050

)))

1051

|8|Position command|(((

1052

In the previous first gain, if the position command is not 0, switch to the second gain;

1053

1054

In the previous second gain, if the position command is 0 and the duration is greater than [P02-13], the first gain is returned.

)))

|(((

9

)))|(((

Positioning complete

)))|(((

In the previous first gain, if the positioning is not completed, the second gain is switched; In the previous second gain, if the positioning is not completed and the duration is greater than [P02-13], the first gain is returned.

)))

|(((

10

)))|(((

Position command + actual speed

1077

)))|(((

1078

In the previous first gain, if the position command is not 0, the second gain is switched;

1079

1080

In the previous second gain, if the position command is 0, the duration is greater than [P02-13] and the absolute value of actual speed is less than ( grade - hysteresis).

)))

)))

|(% rowspan="2" %)

|Delay Time for Gain Switching|Operation setting|Effective immediately|20|0 to 10000|Gain control|0.1ms

1091

|(% colspan="8" %)(((

1092

The duration of the switching condition required for the second gain to switch back to the first gain.

1093

1094

[[image:image-20230515140953-9.png]]

1095

1096

**✎**Note: This parameter is only valid when the second gain is switched back to the first gain.

)))

|(% rowspan="2" %)

|(% colspan="8" %)(((

1103

Set the grade of the gain condition. The generation of the actual switching action is affected by the two conditions of grade and hysteresis.

1104

1105

[[image:image-20230515140953-10.png]]

)))

|(% rowspan="2" %)

|(% colspan="8" %)(((

1112

Set the hysteresis to meet the gain switching condition.

1113

1114

[[image:image-20230515140953-11.png]]

)))

|(% rowspan="2" %)

|Position loop gain switching time|Operation setting|Effective immediately|30|0 to 10000|Gain control|0.1ms

1120

|(% colspan="8" %)(((

1121

Set the time for switching from the first position loop (P02-01) to the second position loop (P02-04) in the position control mode.

1122

1123

[[image:image-20230515140953-12.png]]

1124

1125

If P02-04≤P02-01, then P02-16 is invalid, and the second gain is switched from the first gain immediately.

1126

)))

1127

1128

= **Mechanical resonance suppression** =

1129

1130

== Mechanical resonance suppression methods ==

1131

1132

When the mechanical rigidity is low, vibration and noise may occur due to resonance caused by shaft twisting, and it may not be possible to increase the gain setting. In this case, by using a notch filter to reduce the gain at a specific frequency, after resonance is effectively suppressed, you can continue to increase the servo gain. There are 2 methods to suppress mechanical resonance.

1133

1134

**Torque instruction filter**

1135

1136

By setting the filter time constant, the torque instruction is attenuated in the high frequency range above the cutoff frequency, so as to achieve the expectation of suppressing mechanical resonance. The cut-off frequency of the torque instruction filter could be calculated by the following formula:

1137

1138

(% style="text-align:center" %)

1139

[[image:image-20220706155820-5.jpeg||class="img-thumbnail"]]

**Notch filter**

The notch filter can achieve the expectation of suppressing mechanical resonance by reducing the gain at a specific frequency. When setting the notch filter correctly, the vibration can be effectively suppressed. You can try to increase the servo gain. The principle of the notch filter is shown in __Figure 7-3__.

== Notch filter ==

The VD2 series servo drives have 2 sets of notch filters, each of which has 3 parameters, namely notch frequency, width grade and depth grade.

1148

1149

**Width grade of notch filter**

1150

1151

The notch width grade is used to express the ratio of the notch width to the center frequency of the notch:

1152

1153

(% style="text-align:center" %)

1154

[[image:image-20220706155836-6.png||class="img-thumbnail"]]

1155

1156

In formula (7-1), [[image:image-20220706155946-7.png]] is the center frequency of notch filter, that is, the mechanical resonance frequency; [[image:image-20220706155952-8.png]] is the width of notch filter, which represents the frequency bandwidth with an amplitude attenuation rate of **-3dB** relative to the center frequency of notch filter.

1157

1158

**Depth grade of notch filter**

1159

1160

The depth grade of notch filter represents the ratio relationship between input and output at center frequency.

1161

1162

When the notch filter depth grade is 0, the input is completely suppressed at center frequency. When the notch filter depth grade is 100, the input is completely passable at center frequency. Therefore, the smaller the the notch filter depth grade is set, the deeper the the notch filter depth, and the stronger the suppression of mechanical resonance. But the system may be unstable, you should pay attention to it when using it. The specific relationship is shown in __Figure 7-4__.

1163

1164

(% style="text-align:center" %)

1165

(((

1166

(% class="wikigeneratedid img-thumbnail" style="display:inline-block" %)

1167

[[Figure 7-7 Notch characteristics, notch width, and notch depth>>image:image-20220608174259-3.png||id="Iimage-20220608174259-3.png"]]

)))

(% style="text-align:center" %)

1172

(((

1173

(% class="wikigeneratedid img-thumbnail" style="display:inline-block" %)

1174

[[Figure 7-8 Frequency characteristics of notch filter>>image:image-20220706160046-9.png||id="Iimage-20220706160046-9.png"]]

)))

(% class="table-bordered" %)

1179

|=(% scope="row" style="text-align: center; vertical-align: middle; width: 113px;" %)**Function code**|=(% style="text-align: center; vertical-align: middle; width: 155px;" %)**Name**|=(% style="text-align: center; vertical-align: middle; width: 115px;" %)(((

1180

**Setting method**

1181

)))|=(% style="text-align: center; vertical-align: middle; width: 121px;" %)(((

1182

**Effective time**

1183

)))|=(% style="text-align: center; vertical-align: middle; width: 99px;" %)**Default value**|=(% style="text-align: center; vertical-align: middle; width: 102px;" %)**Range**|=(% style="text-align: center; vertical-align: middle; width: 362px;" %)**Definition**|=(% style="text-align: center; vertical-align: middle; width: 96px;" %)**Unit**

1184

|=(% style="text-align: center; vertical-align: middle; width: 113px;" %)P04-05|(% style="text-align:center; vertical-align:middle; width:155px" %)1st notch filter frequency|(% style="text-align:center; vertical-align:middle; width:115px" %)(((

1185

Operation setting

1186

)))|(% style="text-align:center; vertical-align:middle; width:121px" %)(((

1187

Effective immediately

1188

)))|(% style="text-align:center; vertical-align:middle; width:99px" %)300|(% style="text-align:center; vertical-align:middle; width:102px" %)250 to 5000|(% style="width:362px" %)Set the center frequency of the 1st notch filter. When the set value is 5000, the function of notch filter is invalid.|(% style="text-align:center; vertical-align:middle; width:96px" %)Hz

1189

|=(% style="text-align: center; vertical-align: middle; width: 113px;" %)P04-06|(% style="text-align:center; vertical-align:middle; width:155px" %)1st notch filter depth|(% style="text-align:center; vertical-align:middle; width:115px" %)(((

1190

Operation setting

1191

)))|(% style="text-align:center; vertical-align:middle; width:121px" %)(((

1192

Effective immediately

1193

)))|(% style="text-align:center; vertical-align:middle; width:99px" %)100|(% style="text-align:center; vertical-align:middle; width:102px" %)0 to 100|(% style="width:362px" %)(((

1194

1. 0: all truncated

1195

1. 100: all passed

1196

)))|(% style="text-align:center; vertical-align:middle; width:96px" %)-

1197

|=(% style="text-align: center; vertical-align: middle; width: 113px;" %)P04-07|(% style="text-align:center; vertical-align:middle; width:155px" %)1st notch filter width|(% style="text-align:center; vertical-align:middle; width:115px" %)(((

1198

Operation setting

1199

)))|(% style="text-align:center; vertical-align:middle; width:121px" %)(((

1200

Effective immediately

1201

)))|(% style="text-align:center; vertical-align:middle; width:99px" %)4|(% style="text-align:center; vertical-align:middle; width:102px" %)0 to 12|(% style="width:362px" %)(((

1202

1. 0: 0.5 times the bandwidth

1203

1. 4: 1 times the bandwidth

1204

1. 8: 2 times the bandwidth

1205

1. 12: 4 times the bandwidth

1206

)))|(% style="text-align:center; vertical-align:middle; width:96px" %)-

1207

|=(% style="text-align: center; vertical-align: middle; width: 113px;" %)P04-08|(% style="text-align:center; vertical-align:middle; width:155px" %)2nd notch filter frequency|(% style="text-align:center; vertical-align:middle; width:115px" %)(((

1208

Operation setting

1209

)))|(% style="text-align:center; vertical-align:middle; width:121px" %)(((

1210

Effective immediately

1211

)))|(% style="text-align:center; vertical-align:middle; width:99px" %)500|(% style="text-align:center; vertical-align:middle; width:102px" %)250 to 5000|(% style="width:362px" %)Set the center frequency of the 2nd notch filter. When the set value is 5000, the function of the notch filter is invalid.|(% style="text-align:center; vertical-align:middle; width:96px" %)Hz

1212

|=(% style="text-align: center; vertical-align: middle; width: 113px;" %)P04-09|(% style="text-align:center; vertical-align:middle; width:155px" %)2nd notch filter depth|(% style="text-align:center; vertical-align:middle; width:115px" %)(((

1213

Operation setting

1214

)))|(% style="text-align:center; vertical-align:middle; width:121px" %)(((

1215

Effective immediately

1216

)))|(% style="text-align:center; vertical-align:middle; width:99px" %)100|(% style="text-align:center; vertical-align:middle; width:102px" %)0 to 100|(% style="width:362px" %)(((

1217

1. 0: all truncated

1218

1. 100: all passed

1219

)))|(% style="text-align:center; vertical-align:middle; width:96px" %)-

1220

|=(% style="text-align: center; vertical-align: middle; width: 113px;" %)P04-10|(% style="text-align:center; vertical-align:middle; width:155px" %)2nd notch filter width|(% style="text-align:center; vertical-align:middle; width:115px" %)(((

1221

Operation setting

1222

)))|(% style="text-align:center; vertical-align:middle; width:121px" %)(((

1223

Effective immediately

1224

)))|(% style="text-align:center; vertical-align:middle; width:99px" %)4|(% style="text-align:center; vertical-align:middle; width:102px" %)0 to 12|(% style="width:362px" %)(((

1225

1. 0: 0.5 times the bandwidth

1226

1. 4: 1 times the bandwidth

1227

1. 8: 2 times the bandwidth

1228

1. 12: 4 times the bandwidth

1229

)))|(% style="text-align:center; vertical-align:middle; width:96px" %)-

1230

1231