Motor control device and motor control method

Abstract

The motor control device and the motor control method of the present application shorten the automatic tuning process. The amplitude and the vibration period of the vibration component included in the torque command value are obtained using a servo amplifier (100) that adjusts the gain of a motor (300), and in the case where the amplitude and the vibration period satisfy certain conditions, it is determined that the notch filter (141 and / or 142) needs to be set, and the notch frequency of the notch filter (141 and / or 142) is set to the period of the vibration component immediately before the determination. Thus, without extracting the vibration by Fourier series expansion and without obtaining the amount of data required for frequency analysis, the automatic tuning process can be shortened.

Description

Technical Field

[0001] This invention relates to a motor control device and a motor control method with automatic tuning function. Background Technology

[0002] When installing a servo system motor on a robot or machine tool, the gain of the servo amplifier needs to be adjusted according to the load inertia. This gain adjustment of the servo amplifier is generally performed by a motor control device with automatic tuning function.

[0003] During automatic tuning, multiple tests are performed while changing the tuning parameters, and the next parameter settings are determined based on the results of these tests. Additionally, automatic tuning also includes settings to suppress motor vibration.

[0004] As a device related to the suppression of vibration of such an electric motor, for example, a motor control device is proposed in Patent Document 1, which includes: a rotation control unit that controls the rotation of the motor; an accelerometer as a vibration detection unit that detects the vibration of the rotating motor; a specific frequency component extraction unit that extracts a vibration component of a specific frequency from the vibration detected by the accelerometer; a vibration component decomposition unit that decomposes the vibration of the specific frequency into a main vibration component of the specific frequency and a pulsating vibration component that overlaps with the main vibration component; and a repetition control unit that generates a compensation signal that simultaneously suppresses both the main vibration component and the pulsating vibration component, and repeatedly inputs it to the rotation control unit.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-080614 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] In the motor control device of the aforementioned Patent Document 1, the vibration at a specific frequency is decomposed into a main vibration component and a pulsating vibration component with a certain amplitude to obtain a compensation signal. Therefore, it can be considered that the vibration of the motor can be effectively suppressed.

[0010] However, in this motor control device, when extracting vibration components of a specific frequency from the vibration detected by the acceleration sensor using a specific frequency component extraction unit, only vibrations of the specific frequency are extracted through Fourier series expansion.

[0011] Therefore, if vibration extraction is to be performed using Fourier series expansion, not only will the frequency analysis process take time, but the acquisition of the data required for frequency analysis will also take time, which will hinder the shortening of the automatic tuning process.

[0012] Therefore, it is desirable to develop a shortened motor control device that can achieve automatic tuning.

[0013] The present invention was made in view of the above-mentioned situation, and its object is to provide an electric motor control device and electric motor control method that can eliminate the above-mentioned problems.

[0014] Technical means for solving technical problems

[0015] The electric motor control device of the present invention is characterized by having: a servo amplifier that adjusts the gain of the electric motor; and a notch filter, wherein the servo amplifier acquires the amplitude and period of the vibration component included in the torque command value, and determines that the notch filter needs to be set when the amplitude and period meet certain conditions, and sets the notch frequency of the notch filter to the period of the vibration component immediately preceding the determination.

[0016] The electric motor control method of the present invention is characterized by using a servo amplifier that adjusts the gain of the electric motor to obtain the amplitude and period of the vibration component contained in the torque command value. When the amplitude and period meet certain conditions, it is determined that a notch filter needs to be set, and the notch frequency of the notch filter is set to the period of the vibration component immediately before the determination.

[0017] In the motor control device and motor control method of the present invention, a servo amplifier that adjusts the gain of the motor is used to obtain the amplitude and period of the vibration component included in the torque command value. When the amplitude and period meet certain conditions, it is determined that a notch filter needs to be set, and the notch frequency of the notch filter is set to the period of the vibration component immediately before the determination.

[0018] Invention Effects

[0019] According to the electric motor control device and method of the present invention, vibration is not extracted by Fourier series expansion, and the amount of data required for frequency analysis is not required. Therefore, the processing of automatic tuning can be shortened. Attached Figure Description

[0020] Figure 1 This is a diagram illustrating one embodiment of the electric motor control device of the present invention.

[0021] Figure 2A It is used for based on Figure 1 The diagram illustrating the acquisition of the amplitude and frequency of the vibration component of the servo amplifier is a diagram showing the vibration component included in the torque command value contained in the adjustment command from the torque adjustment unit, for example.

[0022] Figure 2B It is used for utilization Figure 1 The diagram illustrating the acquisition of the amplitude and frequency of the vibration component by the servo amplifier is an example of false detection of the amplitude and period of the generated vibration component.

[0023] Figure 3 It is used for the purpose of... Figure 1 The diagram illustrates the resetting of the torque notch when the servo amplifier is determined to need resetting after the torque notch is set.

[0024] Figure 4 It is used for the purpose of Figure 1 The flowchart illustrates the automatic tuning performed by the servo amplifier.

[0025] Figure 5 It is used for the purpose of Figure 1 The flowchart illustrates the vibration level analysis process performed by the servo amplifier. Detailed Implementation

[0026] The following reference Figures 1-5 One embodiment of the motor control device of the present invention will be described. Furthermore, when the motor control device M described below performs automatic tuning, it needs to adjust the gain of the servo amplifier 100 according to the load inertia; however, for ease of explanation, illustrations and descriptions regarding load inertia are omitted.

[0027] The motor control device M includes a servo amplifier 100 with an automatic tuning function. The servo amplifier 100, for example, acquires the amplitude and period of the vibration component included in the torque command value of the adjustment command from the torque adjustment unit 140. Furthermore, the servo amplifier 100 automatically determines whether torque notch filters 141 and / or 142 (described later) are set based on the amplitude and duration of the vibration component (short duration for high amplitude, long duration for low amplitude). Additionally, if the servo amplifier 100 determines that notch filter 141 and / or 142 (described later) needs to be set, it sets the notch frequency of notch filters 141 and / or 142 to the period of the vibration component immediately preceding the determination. Note: Reference numeral 300 indicates a motor, reference numeral 150 indicates a subtractor, and reference numeral 160 indicates an adder / subtractor.

[0028] The servo amplifier 100 includes a position adjustment unit 110, a feedforward control unit 120, a feedback control unit 130, a torque adjustment unit 140, and a current control unit 170.

[0029] The position adjustment unit 110 outputs a position command corresponding to the gain setting to the feedforward control unit 120 and the subtractor 150 based on a command from a controller (not shown) that includes command values ​​for position, speed, and torque, indicating the target value.

[0030] The feedforward control unit 120 outputs a feedforward command (FF command) to the adder / subtractor 160, which includes a speed command and a torque command for controlling speed and torque, based on the position command from the position adjustment unit 110.

[0031] Based on the feedback signal, the feedback control unit 130 outputs a feedback command (FB command) to the adder / subtractor 160 to make the deviation from the subtractor 150 zero.

[0032] The torque adjustment unit 140 has multiple notch filters 141 and 142. The torque adjustment unit 140 outputs an adjustment command to the current control unit 170 after attenuating the vibration contained in the torque command of the control command from the adder / subtractor 160 using notch filters 141 and / or 142.

[0033] Furthermore, the vibration included in the torque command is caused by the oscillation of the motor 300. Also, the notch filters 141 and 142 are not limited to the two shown in the figure; three or more can be provided. Furthermore, as notch filters 141 and 142, adaptive filters capable of adapting the transfer function according to an optimization algorithm can be used. Details regarding the configuration of notch filters 141 and 142 will be described later.

[0034] Subtractor 150 subtracts the position and speed signals from the position command and feedback signal corresponding to the gain setting from position adjustment unit 110, and outputs the deviation. Adder / subtractor 160 performs subtraction on the feedforward command and feedback command, and outputs a control command to make the deviation from subtractor 150 zero.

[0035] The current control unit 170 controls the drive current of the motor 300 to generate the torque indicated by the adjustment command from the torque adjustment unit 140.

[0036] When this type of motor control device outputs instructions from a controller (not shown), it starts driving the motor 300 based on the feedforward instructions (FF instructions) from the feedforward control unit 120.

[0037] When a feedback signal detected by an encoder (not shown) is output along with the drive of the motor 300, a control command for making the deviation from the subtractor 150 zero is output from the adder / subtractor 160 according to the feedback command (FB command) from the feedback control unit 130. Then, the current control unit 170 controls the drive current of the motor 300 to generate the torque indicated by the adjustment command after vibration damping from the torque adjustment unit 140.

[0038] Next, the acquisition of the amplitude and period of the vibration component of the servo amplifier 100 will be explained with reference to FIG2. Furthermore, conditions 1 to 4 described below are merely examples. In FIG2, the horizontal axis represents time (ms), and the vertical axis represents the torque command value during operation. The torque command value 1000 [0.1%] represents the rated torque.

[0039] Figure 2A This illustrates, for example, the vibration component included in the torque command value contained in the adjustment command from the torque adjustment unit 140. Furthermore, the vibration component included in the torque command value may also be included in the output of the current controller 170. Figure 2A In the diagram, 'a' shows the threshold values ​​used to perform the search for the minimum values ​​P2 and P4 of the vibration components, and 'b' shows the threshold values ​​used to perform the search for the maximum values ​​P1 and P3 of the vibration components. Furthermore, threshold values ​​a and b are not limited to their positions shown in the diagram and can be arbitrarily changed. Additionally, vibration periods S1 and S2 represent the time differences between the maximum values ​​P1 and P3 of adjacent vibration components and between the minimum values ​​P2 and P4.

[0040] The servo amplifier 100 continuously monitors the torque command value contained in the adjustment command from the torque adjustment unit 140 during each position speed control cycle, and acquires the amplitude and period of the vibration component of the torque command value. Furthermore, when acquiring the amplitude and period S1 and S2 of the vibration component, the servo amplifier 100 acquires the polarity switching thresholds a and b. Thresholds a and b can be set according to the acquisition level (or detection level) used to acquire the amplitude and period S1 and S2 of the vibration component.

[0041] When the maximum value P1 and minimum value P2 of the vibration component exceed the threshold values ​​a and b, the servo amplifier 100 calculates PeaktoPeak(PP), which is the difference (amplitude) between the maximum value P1 and the minimum value P2 of the vibration component. In addition, it calculates the vibration periods S1 and S2 between the maximum values ​​P1 and P3 of the vibration components in adjacent periods and between the minimum values ​​P2 and P4 of the vibration components in adjacent periods.

[0042] After determining PeaktoPeak (PP), which is the difference (amplitude) between the maximum value P1 and the minimum value P2 of the vibration component, and the vibration periods S1 and S2, the servo amplifier 100 determines that notch filters 141 and / or 142 need to be set when the following conditions 1 and 2 are met.

[0043] Condition 1: Peak to Peak (PP) exceeds 30% of the rated value, and the vibration period S1 and S2 exceed 10ms.

[0044] Condition 2: Peak to Peak (PP) exceeds the rated value by 10%, and the vibration period S1 and S2 exceed 50ms.

[0045] Furthermore, if oscillation continues even when PeaktoPeak (PP) is small, people may sometimes feel uncomfortable. In this case, the servo amplifier 100 determines that notch filters 141 and / or 142 need to be set if conditions 3 and 4 below are met.

[0046] Condition 3: Peak to Peak (PP) exceeds the rated value by 25%, and the vibration period S1 and S2 exceed 10ms.

[0047] Condition 4: Peak to Peak (PP) exceeds 10%, and vibration periods S1 and S2 exceed 100ms.

[0048] When the servo amplifier 100 determines that it is necessary to set the notch filter 141 and / or 142, it sets the notch frequency of the notch filter 141 and / or 142 to the period of the vibration component immediately preceding the determination.

[0049] Figure 2B This is a diagram illustrating an example of false detection of the amplitude of the generated vibration components and the vibration periods S1 and S2. As shown, sometimes the vibration component of the torque command value rises from the minimum value P2, and just after exceeding the threshold b, the vibration component of the torque command value falls below the threshold b. This is considered to be due to a delay in the follow-up of the gain adjustment of the control parameters performed by the servo amplifier 100 when the motor 300 starts.

[0050] In this case, for example, if PeaktoPeak(PP), which is the difference (amplitude) between the minimum value P2 and the maximum value P5 of the vibration period S2, and PeaktoPeak(PP), which is the difference (amplitude) between the maximum value P5 and the minimum value P6 of the vibration period S2, are significantly different, then the servo amplifier 100 determines that notch filters 141 and / or 142 do not need to be set.

[0051] Figure 3This diagram illustrates the resetting of torque notch 141 and / or 142 when it is determined that resetting is required after torque notch 141 has been set by servo amplifier 100. Additionally, in Figure 3 In the diagram, the horizontal axis represents time (ms), and the vertical axis represents the torque command value during operation and the measured frequency after the notch filter 141 and / or 142 are set.

[0052] For example, even if the notch frequency f1 of the notch filter 141 is set to the period of the vibration component immediately before the determination (immediately before the moment when it is determined that notch filters 141 and / or 142 need to be set due to vibration), the servo amplifier 100 determines that the notch filter 141 needs to be reset if the vibration component does not attenuate and any of the conditions 1 to 4 described above is met. In this case, the servo amplifier 100 changes the notch frequency f1 of the notch filter 141 to the notch frequency f2.

[0053] Here, even if the notch frequency f1 of the notch filter 141 is changed to the notch frequency f2, the vibration component does not attenuate. If any of conditions 1 to 4 above are met, the servo amplifier 100 determines that resetting is required. In this case, since the vibration frequency f3 and the notch frequency f2 are within a certain range (close), the notch frequency f2 of the notch filter 141 is not changed, but the intensity of the notch filter 141 is changed. This changes the depth of the notch frequency f2. Then, the servo amplifier 100 calculates Peak to Peak (PP) and the vibration period. If none of conditions 1 to 4 above are met, it determines that resetting of the notch filters 141 and / or 142 is not required.

[0054] In addition, the servo amplifier 100 does not attenuate the vibration component when the notch frequency f2 of the notch filter 141 is set. When any of the above conditions 1 to 4 are met and the vibration frequency is f1 (near), the servo amplifier 100 sets the notch frequency of the other notch filter 142 to f1.

[0055] Next, refer to Figure 4 The automatic tuning process of the motor control device M will be explained. Additionally, the following section explains the situation related to vibration reduction based on torque adjustment.

[0056] (Step S101)

[0057] Servo amplifier 100 determines whether the target position has changed.

[0058] In this case, if the target position from the controller (not shown) has not changed, the servo amplifier 100 determines that the target position has not changed (step S101: No) and proceeds to step S103.

[0059] In contrast, if the target position from a controller (not shown) changes, the servo amplifier 100 determines that the target position has changed (step S101: Yes) and proceeds to step S102.

[0060] (Step S102)

[0061] The servo amplifier 100 initializes various parameters of the torque adjustment unit 140.

[0062] (Step S103)

[0063] The servo amplifier 100 acquires the torque command value contained in the adjustment command from the torque adjustment unit 140.

[0064] (Step S104)

[0065] Servo amplifier 100 determines whether the acquired torque command value is above the limit.

[0066] In this case, the servo amplifier 100 compares the torque command limit value stored in the limit value table of the allowable torque of the motor 300 (not shown) with the acquired torque command value. If it is determined that the torque command value is not above the limit value (step S104: No), then proceed to step S106.

[0067] In contrast, if the servo amplifier 100 determines that the acquired torque command value is above the torque command limit value stored in the limit value table (step S104: yes), then proceeds to step S105.

[0068] (Step S105)

[0069] Servo amplifier 100 enables the tuning stop flag bit of a tuning table (not shown).

[0070] (Step S106)

[0071] Servo amplifier 100 monitors torque command values.

[0072] In this case, the servo amplifier 100 monitors, for example, the torque command value of the adjustment command from the torque adjustment unit 140 during motor operation.

[0073] (Step S107)

[0074] Servo amplifier 100 calculates the peak to peak (PP) of the vibration component.

[0075] In this case, such as Figure 2A As shown, the servo amplifier 100 calculates PeaktoPeak(PP), which is the difference (amplitude) between the maximum value P1 and the minimum value P2 of the vibration component.

[0076] (Step S108)

[0077] The oscillation periods S1 and S2 are determined using servo amplifier 100.

[0078] In this case, such as Figure 2A As shown, the servo amplifier 100 calculates the difference time between the maximum values ​​P1 and P3 of adjacent vibration components and between the minimum values ​​P2 and P4, which are the vibration periods S1 and S2.

[0079] (Step S109)

[0080] Servo amplifier 100 determines whether the conditions are met.

[0081] In this case, if the PeaktoPeak(PP) and vibration periods S1 and S2 obtained by the servo amplifier 100 in steps S107 and S108 do not meet any of the conditions in conditions 1 and 2 above, it is determined that conditions 1 and 2 are not met (step S109: No), and the process ends.

[0082] In contrast, if PeaktoPeak (PP) and vibration periods S1 and S2 meet any of the conditions 1 and 2 above, the servo amplifier 100 determines that condition 1 or 2 is satisfied (step S109: yes) and proceeds to step S110.

[0083] Furthermore, as mentioned above, even when Peak to Peak (PP) is small, people may sometimes feel uncomfortable if the oscillation continues. In this case, the servo amplifier 100 also determines whether conditions 3 and 4 mentioned above are met.

[0084] (Step S110)

[0085] Servo amplifier 100 sets notch filter 141.

[0086] In this case, when the servo amplifier 100 determines that any of the conditions 1 to 4 are met, it sets the notch frequency of the notch filter 141 and / or 142 to the period of the vibration component immediately preceding the determination.

[0087] (Step S111)

[0088] Servo amplifier 100 determines whether notch filter 141 needs to be reset.

[0089] In this case, the servo amplifier 100, as Figure 3 As shown, for example, even if the notch frequency f1 of the notch filter 141 is set to the period of the vibration component immediately preceding the determination, if the vibration component does not attenuate and meets any of the conditions 1 to 4 above, it is determined that the notch filter 141 needs to be reset (step S111: Yes), and the process proceeds to step S112.

[0090] In contrast, if the servo amplifier 100 sets the notch frequency f1 of the notch filter 141 to the period of the vibration component immediately preceding the determination, the vibration component is attenuated. If none of the conditions in conditions 1 to 4 are met, it is determined that the notch filter 141 does not need to be reset (step S111: No), and the process ends.

[0091] (Step S112)

[0092] Servo amplifier 100 reconfigures notch filter 141.

[0093] In this case, the servo amplifier 100 changes the notch frequency f1 of the notch filter 141 to the notch frequency f2. Even when the notch frequency f1 of the notch filter 141 is changed to the notch frequency f2, if the vibration component does not attenuate and any of the conditions 1 to 4 above are met, since the vibration frequency f3 and the notch frequency f2 are within a certain range (close), the servo amplifier 100 does not change the notch frequency f2 of the notch filter 141, but rather changes the intensity of the notch filter 141. This changes the depth of the notch frequency f2.

[0094] In addition, when the vibration frequency is f1 (near), the servo amplifier 100 sets the notch frequency of the other notch filters 142 to f1.

[0095] Subsequently, the servo amplifier 100 calculates Peak to Peak (PP) and vibration periods S1 and S2. If none of the conditions in conditions 1 to 4 are met, the resetting of the notch filter 141 is terminated.

[0096] Next, refer to Figure 5 This section explains the vibration level analysis and processing of the servo amplifier 100. Additionally, the following explanation is... Figure 4 A detailed example of steps S107 and S108.

[0097] (Step S201)

[0098] Servo amplifier 100 determines whether the polarity is positive or negative.

[0099] In this case, if the servo amplifier 100 obtains the threshold b in the analysis of the vibration component, it determines that the polarity is positive (step S201: positive) and proceeds to step S202.

[0100] In contrast, if the servo amplifier 100 obtains a threshold a in the analysis of the vibration component, it determines that the polarity is negative (step S201: negative) and proceeds to step S209.

[0101] (Step S202)

[0102] The servo amplifier 100 implements a process to find the maximum value and determines whether it is above the maximum value.

[0103] In this case, if the current value does not exceed the maximum value in the analysis of the vibration component, the servo amplifier 100 determines that it is less than the maximum value (step S202: no) and proceeds to step S204.

[0104] In contrast, if the current value exceeds the maximum value in the analysis of the vibration component, the servo amplifier 100 determines that it is above the maximum value (step S202: yes) and proceeds to step S203.

[0105] (Step S203)

[0106] Servo amplifier 100 updates the maximum value to the current value.

[0107] (Step S204)

[0108] Servo amplifier 100 determines whether it is below the threshold.

[0109] In this case, if the servo amplifier 100 determines that the vibration component is above the threshold a (step S204: no) during the analysis of the vibration component, the process ends.

[0110] In contrast, if the servo amplifier 100 determines that the threshold a is below (step S204: yes), it proceeds to step S205.

[0111] In addition, the servo amplifier 100 detects vibration when it determines that the vibration is below the threshold a.

[0112] (Step S205)

[0113] Servo amplifier 100 determines whether there was a previous measurement.

[0114] In this case, the servo amplifier 100 proceeds to step S207 if there is no previous measurement (step S205: No).

[0115] In contrast, if there is a previous measurement (step S205: yes), the servo amplifier 100 proceeds to step S206.

[0116] In addition, the servo amplifier 100 does not detect vibration in the absence of a previous measurement because it cannot measure the amplitude and vibration period S1 and S2 in the first measurement.

[0117] (Step S206)

[0118] Servo amplifier 100 acquires the amplitude and vibration period S1 and S2.

[0119] (Step S207)

[0120] Servo amplifier 100 changes the minimum value to the current value.

[0121] (Step S208)

[0122] Servo amplifier 100 changes its polarity to negative.

[0123] (Step S209)

[0124] Servo amplifier 100 determines whether the value is below the minimum value.

[0125] In this case, if the servo amplifier 100 determines in the analysis of the vibration component that the current value is not below the minimum value (step S209: No), it proceeds to step S211.

[0126] In contrast, when the servo amplifier 100 determines in the analysis of the vibration components that the current value is below the minimum value (step S209: Yes), it proceeds to step S210.

[0127] (Step S210)

[0128] Servo amplifier 100 updates the maximum value to the current value.

[0129] (Step S211)

[0130] Servo amplifier 100 determines whether the threshold is exceeded.

[0131] In this case, if the servo amplifier 100 determines that the vibration component is above the threshold b (step S211: yes) during the analysis of the vibration component, it proceeds to step S212.

[0132] In contrast, if the servo amplifier 100 determines that the threshold b is below the threshold (step S204: no), then the process ends.

[0133] (Step S212)

[0134] Servo amplifier 100 determines whether there was a previous measurement.

[0135] In this case, the servo amplifier 100 proceeds to step S214 if there is no previous measurement (step S212: No).

[0136] In contrast, if there is a previous measurement (step S212: yes), the servo amplifier 100 proceeds to step S213.

[0137] In addition, the servo amplifier 100 does not detect vibration in the absence of a previous measurement because it cannot measure the amplitude and vibration period S1 and S2 in the first measurement.

[0138] (Step S213)

[0139] Servo amplifier 100 acquires the amplitude and vibration period S1 and S2.

[0140] (Step S214)

[0141] Servo amplifier 100 changes the maximum value to the current value.

[0142] (Step S215)

[0143] Servo amplifier 100 changes the polarity to positive.

[0144] Thus, in this embodiment, by adjusting the gain of the servo amplifier 100 of the motor 300, the amplitude and period of the vibration component included in the torque command value are obtained. If the amplitude and period meet certain conditions, it is determined that notch filters 141 and / or 142 need to be set, and the notch frequency of notch filters 141 and / or 142 is set to the period of the vibration component immediately preceding the determination. Therefore, it is not necessary to extract vibration through Fourier series expansion, and the amount of data required for frequency analysis is not needed, thus shortening the automatic tuning process.

[0145] Label Explanation

[0146] 100 servo amplifier

[0147] 110 Position Adjustment Section

[0148] 120 Feedforward Control Unit

[0149] 130 Feedback Control Department

[0150] 140 Torque Adjustment Unit

[0151] 150 subtractor

[0152] 160 Adder / Subtractor

[0153] 170 Current Control Section

[0154] 300 electric motor

[0155] M motor control device.

Claims

1. A motor control device, characterized in that, have: A servo amplifier that adjusts the gain of the motor; and Notch filter, The servo amplifier acquires the amplitude and period of the vibration component contained in the torque command value. If the amplitude exceeds a first threshold and the period exceeds a second threshold, it determines that the notch filter needs to be set, and sets the notch frequency of the notch filter to the frequency corresponding to the period of the vibration component immediately before the determination.

2. The motor control device as described in claim 1, characterized in that, If any one of conditions 1, 2, 3, and 4 is met, it is determined that the notch filter needs to be set, and the notch frequency of the notch filter is set to the frequency corresponding to the period of the vibration component immediately preceding the determination. Wherein, condition 1 is that the amplitude exceeds 30% of the rated value and the vibration period exceeds 10 ms, condition 2 is that the amplitude exceeds 10% of the rated value and the vibration period exceeds 50 ms, condition 3 is that the amplitude exceeds 25% of the rated value and the vibration period exceeds 10 ms, and condition 4 is that the amplitude exceeds 10% of the rated value and the vibration period exceeds 100 ms.

3. The motor control device as described in claim 1 or 2, characterized in that, After setting the notch filter, the servo amplifier changes the notch frequency and / or intensity of the notch filter without attenuating the vibration component.

4. A method for controlling an electric motor, characterized in that, A servo amplifier that adjusts the gain of the motor is used to obtain the amplitude and period of the vibration component contained in the torque command value. If the amplitude exceeds a first threshold and the period exceeds a second threshold, it is determined that a notch filter needs to be set, and the notch frequency of the notch filter is set to the frequency corresponding to the period of the vibration component immediately before the determination.

5. The motor control method as described in claim 4, characterized in that, If any one of conditions 1, 2, 3, and 4 is met, it is determined that the notch filter needs to be set, and the notch frequency of the notch filter is set to the frequency corresponding to the period of the vibration component immediately preceding the determination. Wherein, condition 1 is that the amplitude exceeds 30% of the rated value and the vibration period exceeds 10 ms, condition 2 is that the amplitude exceeds 10% of the rated value and the vibration period exceeds 50 ms, condition 3 is that the amplitude exceeds 25% of the rated value and the vibration period exceeds 10 ms, and condition 4 is that the amplitude exceeds 10% of the rated value and the vibration period exceeds 100 ms.

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