JP2010220278A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller for controlling the behavior and operation of a motor and a load thereof while always securing a stable control state. <P>SOLUTION: The motor controller 10 having a speed control system for controlling speed feedback based on a speed detection signal Vd and a speed command signal Vr includes a notch filter 15a for attenuating a signal component of a notch frequency for a control signal in the speed control system, a vibration extracting filter 17 for extracting a signal component of a predetermined frequency from the speed detection signal Vd and outputting the extracted component as an extraction signal x, a dead zone processing section 20 for removing a signal component of amplitude of a dead threshold value or below from the extraction signal x in response to the speed command signal Vr, and outputting the signal as an extraction vibration signal xe, and a notch control section 30 for controlling the notch filter 15a so that the notch frequency can be changed based on the extraction vibration signal xe. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor control device that controls electric motors and loads driven by the electric motors, such as speed and position, and more particularly to suppressing mechanical resonance that occurs when driving loads. The present invention relates to a motor control device having a function.

  Conventionally, as this kind of electric motor control device, there has been one as described in Patent Document 1, for example. FIG. 9 is a block diagram showing a configuration of a conventional motor control device.

  A conventional motor control device 90 shown in FIG. 9 is connected to the motor 11 and the speed detector 13. A load 12 is connected to the electric motor 11. The speed detector 13 detects the rotational speed of the electric motor 11 and outputs a speed detection signal Vd indicating the detected rotational speed.

  The electric motor control device 90 has a speed control system that causes the speed detection signal Vd to follow the speed command signal Vr. The electric motor control device 90 includes a notch filter 15 as shown in FIG. 9 in order to suppress oscillation caused by mechanical resonance or the like. Furthermore, the motor control device 90 includes a speed control unit 14, a vibration extraction filter 17, a notch control unit 30, and a torque control unit 16.

  The speed controller 14 receives the speed command signal Vr and the speed detection signal Vd and generates a torque command signal τ1. The notch filter 15 performs a filter process for attenuating the signal component of the notch frequency on the torque command signal τ 1 according to the control of the notch control unit 30, and supplies the filtered torque command signal τ 2 to the torque control unit 16. To do. The torque control unit 16 controls the electric motor 11 so that the electric motor 11 outputs a target torque based on the torque command signal τ2.

  The vibration extraction filter 17 extracts a signal having an oscillation frequency caused by mechanical resonance from the speed detection signal Vd, and outputs the signal as an extraction signal x. The notch control unit 30 controls the notch filter 15 so that the notch frequency of the notch filter 15 becomes the frequency of the extraction signal x.

  In the conventional motor control apparatus configured as described above, even if oscillation due to mechanical resonance occurs for some reason, the notch frequency of the notch filter 15 is sequentially corrected so that the vibration component due to this oscillation is reduced, so that oscillation is suppressed. The For this reason, the system using the conventional motor control device can obtain a stable control state.

  However, there are cases where noise, for example, high-frequency components due to the acceleration change of the speed command, etc. are mixed in the extraction signal x extracted by the vibration extraction filter 17, which deteriorates the stability of the speed control system and causes malfunction. Could cause. For this reason, for example, in Patent Document 1, in order to prevent malfunction due to a high-frequency component generated when the speed command is changed, the operation of the notch control unit is temporarily performed for a period during which the speed command is non-zero and for a predetermined time from the end of the speed command. An electric motor control device having a function of stopping is disclosed.

On the other hand, similarly, in order to suppress malfunction caused by noise included in the detected vibration component, a signal component having a minute amplitude is conventionally removed after the filter for extracting the vibration component as in Patent Document 2, for example. Actuators with functions have been proposed. Such a conventional actuator has a dead zone processing function having a predetermined dead zone area adapted to the noise level of the acceleration sensor, suppresses excitation of a load due to noise of the acceleration sensor, and reduces false vibration.
JP 2004-274976 A International Publication No. 02/083541 Pamphlet

  However, in the configuration in which the operation of the notch control unit is stopped only for a predetermined period in order to prevent malfunction due to high frequency components as in Patent Document 1, mechanical resonance using the notch control unit or the notch filter is performed during the predetermined period. Processing to suppress is also stopped, and there is a problem that mechanical resonance cannot be suppressed during this period. In addition, as in Patent Document 2, a configuration in which a dead zone processing function is provided and the dead zone area is set to a predetermined value adapted to the noise level cannot sufficiently suppress the influence of high frequency components generated when the speed command changes. There was a problem. That is, for example, when a high-frequency component having a certain amplitude is generated by a speed command having a large change, such a high-frequency component passes through the dead zone processing function and reaches the notch control unit. And since such a high frequency component is not a vibration component due to mechanical resonance, it is not necessary to suppress the vibration with the notch filter, but the notch control unit reacts to this high frequency component and an originally unnecessary notch filter is generated. . For this reason, the speed control system may become unstable.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an electric motor control device that controls the movement operation of the electric motor and its load while always ensuring a stable control state. .

  In order to achieve the above object, the electric motor control device of the present invention is based on a detection signal indicating the detected amount of movement of the movable part and a command signal indicating an instruction amount for instructing the amount of movement of the movable part. An electric motor control device having a control system that performs feedback control so that the movement of a movable part by an electric motor follows a command amount, and attenuates a signal component having a frequency that is a notch frequency with respect to a control signal in the control system A notch filter, an extraction filter that extracts a signal component of a predetermined frequency from the detection signal and outputs it as an extraction signal, and a signal component having an amplitude that is less than or equal to the dead threshold value is removed from the extraction signal in accordance with the command signal, and the extracted vibration signal The configuration includes a dead zone processing unit that outputs and a notch control unit that controls the notch filter so as to change the notch frequency based on the extracted vibration signal.

  With such a configuration, for example, the command amount is suddenly changed, so even if a high-frequency component with a large amplitude is mixed into the extracted signal due to this change, the dead threshold is set to a value corresponding to the command signal. Thus, this high frequency component can be removed from the extracted signal. On the other hand, when there is no change in the command signal, for example, the insensitive threshold can be set to the noise level, and only the vibration component based on the mechanical resonance can be supplied to the notch controller with high accuracy. Thus, the present invention can adaptively set the dead threshold value, so that mechanical resonance can always be stably suppressed without being affected by changes in the command amount such as the speed command.

  The electric motor control device of the present invention further includes a dead zone control unit that notifies the dead zone processing unit of a threshold setting signal based on the command signal, and the dead zone processing unit sets a threshold corresponding to the threshold setting signal as a dead threshold. It is a configuration.

  With such a configuration, even when a high-frequency component having a large amplitude is generated due to a large change in the command amount, the dead-band processing unit can adaptively remove the high-frequency component from the extracted signal. For this reason, it is possible to suppress the mechanical resonance while ensuring a stable control system without being affected by changes in the command amount such as the speed command.

  The motor control device according to the present invention is configured such that the dead threshold value is set to a plurality of threshold values that are set to the smallest threshold value and increase according to the magnitude of the threshold value setting signal.

  In the motor control device of the present invention, the dead zone control unit notifies the dead zone processing unit of a threshold setting signal indicating the magnitude of the command signal.

  The motor control device of the present invention may be configured such that the dead zone control unit notifies the dead zone processing unit of a threshold setting signal indicating a moving average value of the command signal.

  In addition, the motor control device of the present invention may be configured such that the dead zone control unit notifies the dead zone processing unit of a threshold setting signal indicating the absolute value of the differential value of the command signal.

  In addition, the electric motor control device of the present invention is configured to set a threshold value larger than the minimum threshold value as the insensitive threshold value during a period when the threshold setting signal is non-zero and a predetermined period from the time when the threshold setting signal becomes zero.

  With such a configuration, a period in which a high-frequency component having a large amplitude due to a change in the command amount may be mixed in the extracted signal, such as a period when the command signal is non-zero, is a threshold value that is larger than the minimum threshold value as a dead threshold value. Therefore, the mechanical resonance can always be stably suppressed without being affected by the change in the command amount.

  In addition, in the motor control device of the present invention, when the dead band processing unit outputs the amplitude as zero when the amplitude of the extraction signal is equal to or less than the dead threshold, and when the amplitude of the extraction signal exceeds the dead threshold, the input extraction signal Is output as it is.

  In addition, in the motor control device of the present invention, when the dead band processing unit outputs the amplitude as zero when the amplitude of the extraction signal is equal to or less than the dead threshold, and when the amplitude of the extraction signal exceeds the dead threshold, the input extraction signal A configuration may be used in which the amplitude of is reduced by the insensitive threshold and output.

  With such a configuration, it is possible to realize a dead zone processing unit that can remove a signal component having a small amplitude that is equal to or smaller than the dead threshold from the extracted signal.

  In the motor control device of the present invention, the notch filter is a filter that attenuates a signal having a notch frequency including a signal component having a near frequency corresponding to the notch width with the notch center frequency as a center, and the notch frequency can be changed. There is a configuration in which the filter can be switched between valid and invalid.

  In the motor control device of the present invention, the extraction filter may be a high-pass filter that extracts a signal component having a predetermined frequency or more included in the detection signal, or a band-pass filter that extracts a signal component within a predetermined frequency bandwidth as a vibration component. This is the configuration.

  Further, the motor control device of the present invention is configured such that the notch control unit sequentially corrects the notch frequency of the notch filter so that the amplitude of the extracted vibration signal is reduced.

  With such a configuration, a notch filter having a notch frequency corresponding to the frequency of vibration generated by mechanical resonance can be automatically generated, so that stable resonance and high-speed response can be realized.

  Further, the motor control device of the present invention is configured such that the insensitive threshold is calculated based on at least one of a gain of the control system, a command signal command unit, and a detection signal detection unit.

  With such a configuration, it is possible to set each threshold value to be an insensitive threshold value to an appropriate value according to the control condition.

  The electric motor control device of the present invention is a control system in which the control system controls either the speed or the position indicating the amount of movement of the movable part.

  In the electric motor control device of the present invention, the movable part is either the movable part of the electric motor or a load driven by the electric motor.

  In addition, the electric motor control device of the present invention performs a moving operation in which the movable part rotates.

  The motor control device of the present invention can be suitably applied to such a configuration.

  According to the motor control device of the present invention, it is possible to always stably suppress the mechanical resonance without being affected by a change in the command amount such as the speed command. It is possible to provide an electric motor control device that controls the movement operation of the load.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a block diagram showing a configuration of an electric motor control device 10 according to an embodiment of the present invention.

  As shown in FIG. 1, the electric motor control device 10 in the embodiment of the present invention is connected to an electric motor 11 and a speed detector 13. A load 12 is connected to the electric motor 11. The speed detector 13 measures the rotational speed of a mover (not shown) provided in the electric motor 11 and outputs a speed detection signal Vd as a detection signal indicating a speed amount corresponding to the rotational speed. On the other hand, in order to command the rotational speed of the mover, the motor control device 10 is notified of a speed command signal Vr indicating the command speed.

  As described above, in the present embodiment, the speed detection signal Vd indicating the rotation speed of the mover is notified as the detection signal indicating the detected amount of movement of the movable part, and a command is used to control the amount of movement. A speed command signal Vr indicating a command speed for commanding the rotation speed is notified as a command signal indicating the commanded amount. The motor control device 10 has a speed control system that performs feedback control so that the rotational movement of the mover follows the command speed based on the speed detection signal Vd and the speed command signal Vr as a control system that performs feedback control. ing. In the present embodiment, an example of a motor control device having such a speed control system will be described.

  As shown in FIG. 1, the motor control device 10 includes a speed control unit 14, a notch filter 15a, a torque control unit 16, a vibration extraction filter 17, a dead zone processing unit 20, a dead zone control unit 21, and a notch control. Part 30.

  A speed command signal Vr indicating a command speed and a speed detection signal Vd indicating a detected speed detected by the speed detector 13 are input to the speed control unit 14. The speed controller 14 calculates a deviation amount between the speed command signal Vr and the speed detection signal Vd, and generates and outputs a torque command signal τ1 for controlling the deviation amount to zero based on the deviation amount. Specifically, the speed control unit 14 calculates, for example, a difference value between the speed command signal Vr and the speed detection signal Vd, and outputs a result obtained by proportionally integrating the difference value as the torque command signal τ1.

  A torque command signal τ1 is supplied from the speed controller 14 to the notch filter 15a. The notch filter 15a is a filter that gives a steep attenuation to a signal component having a predetermined range of frequencies centered on a specific frequency included in the signal from the supplied signal. This center frequency is called the notch center frequency, the frequency width near the attenuation is called the notch width, and the frequency specified by the notch center frequency and the notch width is called the notch frequency. The notch filter 15a has such characteristics. In the present embodiment, the notch frequency signal component is attenuated with respect to the torque command signal τ1, which is a control signal in the speed control system.

  FIG. 2 is a characteristic diagram showing an example of frequency characteristics and phase characteristics of the notch filter 15a of the motor control device 10 according to the embodiment of the present invention. FIG. 2 shows an example of a frequency characteristic that attenuates a signal component in a frequency band of a nearby frequency having a notch width Bn with the notch center frequency ωn as the center. Although details will be described below, the notch filter 15a is configured such that the notch center frequency ωn can be varied. Furthermore, the notch filter 15a is configured to be able to switch the filter function having frequency characteristics as shown in FIG. 2 between a valid state that is valid and a invalid state that is invalid. The valid state of the notch filter 15a is a state in which the signal component in the frequency band of the notch width Bn centered on the notch center frequency ωn is removed from the input signal and outputted, and the invalid state is a state in which the input signal is outputted as it is. It is.

  The notch filter 15a is a second-order recursive notch filter having a transfer function Ha (s) expressed by the following equation, for example.

  In (Expression 1), ωna is a notch center frequency of the notch filter 15a, and ζa is an attenuation constant.

  The notch filter 15a outputs a torque command signal τ2, which is a signal obtained by filtering the torque command signal τ1 as necessary.

  The torque command signal τ2 output from the notch filter 15a is input to the torque control unit 16. The torque control unit 16 controls the rotation operation of the electric motor 11 so that the electric motor 11 outputs a target torque.

  In this way, the motor control device 10 uses the speed detection signal Vd indicating the rotation speed of the mover detected by the speed detector 13, and the rotation speed of the mover corresponds to the speed command signal Vr. A control system is configured as a speed control system that feedback-controls the movement of the mover so as to achieve the rotational speed. And the electric motor control apparatus 10 is the structure which has arrange | positioned the notch filter 15a in this speed control system.

  In the present embodiment, the motor control device 10 has a function of suppressing mechanical resonance that occurs when the load 12 is driven. In order to realize this function, the motor control device 10 arranges the notch filter 15a as described above in the speed control system, and first, a vibration extraction filter that is an extraction filter for extracting vibration components such as mechanical resonance. 17 is provided. The speed detection signal Vd output from the speed detector 13 is also supplied to the vibration extraction filter 17. The vibration extraction filter 17 is set with a predetermined frequency band, and extracts a vibration component included in the frequency band from the speed detection signal Vd based on the set frequency band. That is, the vibration extraction filter 17 extracts and outputs a vibration component that appears in the input speed detection signal Vd, such as a vibration frequency component of mechanical resonance that occurs when the load 12 is driven by the electric motor 11, for example. Since the vibration extraction filter 17 only needs to be able to extract the vibration component in this way, it may be a high-pass filter that allows a signal component of a predetermined frequency or higher to pass, and a signal within a predetermined frequency bandwidth that does not include a series component. A band-pass filter that allows the component to pass therethrough may be used. The vibration extraction filter 17 outputs an extracted signal x that is a signal obtained by extracting a signal that has passed based on such frequency characteristics, that is, a vibration component that has appeared in the speed detection signal Vd.

  The extraction signal x output from the vibration extraction filter 17 is supplied to the dead zone processing unit 20. The dead zone processing unit 20 removes a small-amplitude signal component that is equal to or less than the value set as the dead threshold Th from the extracted signal x, and outputs it as an extracted vibration signal xe. Further, the value of the insensitive threshold Th is set according to the speed command signal Vr. The dead band processing unit 20 performs nonlinear processing having a region to be a dead band in order to realize a function of removing such a small amplitude signal component.

  FIG. 3 is a characteristic diagram showing an example of the non-linear characteristic of the dead zone processing unit 20 of the motor control device 10 according to the embodiment of the present invention. In FIG. 3, the horizontal axis indicates the input value to the dead zone processing unit 20, the vertical axis indicates the output value from the dead zone processing unit 20, and the case where the dead threshold Th becomes the threshold Th0 is indicated by a solid line. In addition, as shown in FIGS. 3A and 3B, two types of characteristic examples are shown.

  In the case of the characteristics shown in FIG. 3A, the dead zone processing unit 20 outputs the extracted vibration signal xe having a value of zero when the amplitude of the extracted signal x is equal to or less than the dead threshold Th. Further, when the amplitude of the extraction signal x exceeds the dead threshold Th, the dead zone processing unit 20 outputs the input extraction signal x as it is as the extraction vibration signal xe. More specifically, the dead zone processing unit 20 outputs an extraction vibration signal xe having a value of zero when the absolute value of the value of the input extraction signal x is equal to or less than the dead threshold Th, and the input extraction signal When the absolute value of x exceeds the dead threshold Th, the input extracted signal x is output as it is as the extracted vibration signal xe.

  On the other hand, in the case of the characteristics shown in FIG. 3B, the dead zone processing unit 20 outputs the extracted vibration signal xe having a value of zero when the amplitude of the extracted signal x is equal to or less than the dead threshold Th. In addition, when the amplitude of the extraction signal x exceeds the dead threshold Th, the dead zone processing unit 20 reduces the amplitude of the input extracted signal x by the dead threshold Th and outputs it. More specifically, the dead zone processing unit 20 outputs the extracted vibration signal xe having a value of zero when the absolute value of the input extracted signal x is equal to or less than the dead threshold Th. When the absolute value of the input extracted signal x exceeds the dead threshold Th, and the extracted signal x is positive, a value obtained by subtracting the dead threshold Th from the extracted signal x and the extracted signal x are In the negative case, the extracted vibration signal xe having a value obtained by adding the dead threshold Th to the extracted signal x is output.

  As described above, the dead band processing unit 20 can selectively remove small amplitude signal components from the extracted signal x by performing nonlinear processing as shown in FIGS. 3A and 3B. That is, noise of a minute amplitude included in the extraction signal x extracted by the vibration extraction filter 17 is removed by such processing of the dead zone processing unit 20.

  The extracted vibration signal xe from which the small-amplitude signal component has been removed by the dead band processing unit 20 is supplied to the notch control unit 30. The notch control unit 30 outputs a notch control signal cn corresponding to the vibration component extraction result by the vibration extraction filter 17 to control the notch filter 15a. In particular, when the notch control unit 30 determines that the vibration component is detected based on the supplied extracted vibration signal xe, the notch filter 15a sets the notch frequency of the notch filter 15a so that the amplitude of the vibration component included in the extracted vibration signal xe is reduced. Control. The notch control unit 30 also performs an operation for switching the notch filter 15a between a valid state and an invalid state.

  The notch control unit 30 controls the notch filter 15a in this way, so that even if oscillation due to mechanical resonance or the like occurs, the notch frequency of the notch filter 15a is sequentially corrected so that the vibration component is reduced, so that oscillation is suppressed. Is done. As described above, the motor control device 10 includes an oscillation suppression function including the notch filter 15a, the vibration extraction filter 17, the dead zone processing unit 20, and the notch control unit 30. In the present embodiment, with such an oscillation suppression function, the system using the motor control device 10 is brought into a stable control state, and stabilization when the load 12 is driven by the motor 11 is achieved.

  Furthermore, as described above, the extraction signal x extracted by the vibration extraction filter 17 includes, for example, a high-frequency component having a certain amplitude due to a change in acceleration of the speed command in addition to a random minute noise component. In the present embodiment, a dead zone control unit 21 that controls the non-linear processing of the dead zone processing unit 20 is provided in order to suppress such adverse effects due to high frequency components and the like.

  The dead zone control unit 21 controls the dead zone processing unit 20 so that a dead zone threshold Th having a value corresponding to the speed command signal Vr is set. In order to perform such control, the dead zone controller 21 is notified of the speed command signal Vr. The dead zone controller 21 generates a threshold setting signal ct indicating the value of the dead threshold Th based on the notified speed command signal Vr and notifies the dead zone processor 20 of the threshold setting signal ct. The dead zone processing unit 20 sets a threshold value that is a value corresponding to the threshold setting signal ct as the dead threshold value Th. That is, when notified to set the threshold Th0 by the threshold setting signal ct, the dead zone processing unit 20 sets the nonlinear characteristic as shown by the solid line in FIG. When notified to set the threshold Th1 by the threshold setting signal ct, the dead zone processing unit 20 sets a nonlinear characteristic as shown by a dotted line in FIG. Here, for example, when a threshold value Th1 larger than the threshold value Th0 is set as the insensitive threshold value Th, signal components having a wider range of amplitude are removed. As described above, the present embodiment also has a function of adaptively removing small amplitude signal components from the extracted signal x in accordance with the speed command signal Vr. Hereinafter, as shown in FIG. 3, the dead zone processing unit 20 is an example having two threshold values, a threshold value Th0 as a minimum threshold value, which is the smallest threshold value, and a threshold value Th1, which is larger than the threshold value Th0, as shown in FIG. It explains using. Although details will be described below, each threshold value is set so that the threshold value also increases in accordance with the magnitude of the speed command signal Vr.

  The dead zone control unit 21 controls the dead zone processing unit 20 in this manner, so that it is possible to appropriately remove a high frequency component having a certain large amplitude when the speed command signal Vr changes, from the extracted signal x. As described above, in the present embodiment, the dead zone processing unit 20 can adaptively set the dead zone threshold Th, so that mechanical resonance can always be stably suppressed without being affected by changes in the command amount such as the speed command. .

  By the way, as a factor of vibration components other than mechanical resonance extracted by the vibration extraction filter 17, there are vibration components caused by speed command resolution, speed detection resolution, and the like in addition to the above-described high frequency components mixed when the speed command changes. For example, when the speed command resolution is coarse, the desired speed command may not be an integral multiple of the speed command resolution. At this time, the average value of the speed command values is the speed command to be given, but the actual speed command value is changed up and down with respect to the speed command to be given. Specifically, when the motor control device 10 is digitally processed, the speed command signal Vr and the speed detection signal Vd that are digital signals are expressed by a finite bit length. For example, the least significant bit is 0 and 1 The phenomenon that repeats. That is, for example, the actual speed command signal Vr includes a high-frequency component due to such a change. When speed control is performed so as to follow such a speed command signal Vr, the actual speed also includes fluctuations due to high frequency components. The level of the high frequency component is larger as the resolution is coarser, that is, the number of bits of the digital signal in the case of digital processing is smaller. Even if the speed command you want to give is an integer multiple of the resolution of the speed command, if the speed command you want to give does not become an integer multiple of the resolution of the speed detection, the detected speed will change above and below the speed command you want to give. End up. Even in such a case, the speed detection signal Vd includes a high-frequency component, and the level of the high-frequency component is larger as the resolution is coarser.

  When the speed command signal Vr includes a change point due to acceleration, as described above, the extraction signal x output from the vibration extraction filter 17 includes a high-frequency component due to acceleration change. Further, the amplitude of the high frequency component resulting from the acceleration change is often larger than the amplitude of the high frequency component resulting from the speed command resolution or the speed detection resolution.

  Based on such a reason, in the present embodiment, the dead zone processing unit 20 adaptively associates the value of the dead threshold Th with the high frequency component resulting from the speed command resolution and the high frequency component resulting from the acceleration change. .

  Next, the operation of the motor control device 10 will be described focusing on the operations of the dead zone control unit 21 and the dead zone processing unit 20.

  FIG. 4 is a diagram illustrating operations of the dead zone processing unit 20 and the dead zone control unit 21 of the motor control device 10 according to the embodiment of the present invention. In FIG. 4, FIGS. 4 (a) to 4 (e) show changes in the level of the time t of the speed command signal Vr, the speed detection signal Vd, the extraction signal x, the dead threshold Th, and the extraction vibration signal xe, respectively.

  First, the operation of the dead zone controller 21 will be described with reference to FIG. The dead zone control unit 21 generates a threshold setting signal ct indicating the value of the dead threshold Th based on the speed command signal Vr notified as described above. Basically, the dead zone controller 21 generates a threshold setting signal ct indicating whether the speed command signal Vr is zero or not. More specifically, as shown in FIG. 4D, the threshold value Th1 is selected as the dead threshold value Th when the speed command signal Vr is non-zero and for a certain period after the speed command signal Vr becomes zero. In other periods, the threshold setting signal ct is generated so that the threshold Th0 is selected as the insensitive threshold Th.

  That is, the amplitude of the high-frequency component due to the acceleration change of the speed command is often larger than the amplitude of noise or the like due to others. For this reason, it is preferable to increase the insensitive threshold Th when an acceleration change occurs in the speed command, and to decrease the insensitive threshold Th when no acceleration change occurs in the speed command. Therefore, the threshold value of the dead zone processing unit is calculated as follows.

  The threshold value Th1 set as the dead zone threshold Th of the dead zone processing unit 20 for a predetermined period after the velocity command signal Vr is non-zero and the speed command ends is set to a value larger than the amplitude of the high frequency component due to the acceleration change of the velocity command. . Specifically, the threshold Th1 is calculated in consideration of the gain of the speed control unit 14, the acceleration change of the speed command, the cutoff frequency of the vibration extraction filter 17, the command unit of the command signal, the detection unit of the detection signal, and the like. . The command unit and the detection unit are, for example, rpm and rps indicating the number of rotations per unit time in the case of speed.

  When the speed command signal Vr takes a value other than the above, the threshold Th0 set as the dead threshold Th of the dead zone processing unit 20 is larger than the amplitude of the signal component due to noise or speed detection resolution, and the speed command It is made smaller than the amplitude of the high frequency component resulting from the acceleration change. That is, the threshold value Th0 is set to a value that is larger than the amplitude of the signal component due to noise or speed detection resolution and smaller than the threshold value Th1. In addition, the threshold Th0 also specifically takes into account the gain of the speed control unit 14, the acceleration change of the speed command, the cutoff frequency of the vibration extraction filter 17, the command unit of the command signal, the detection unit of the detection signal, and the like. calculate.

  Next, the operation of the dead zone processing unit 20 will be described with reference to FIG.

  FIG. 4 shows the waveform of each signal when the speed command signal Vr is changed as shown in FIG. First, until time t1, the speed command signal Vr is set to zero, that is, the motor 11 is instructed to be stopped. In the period from time t1 to time t2, the speed command signal Vr is increased linearly from zero, and in the period from time t2 to time t3, the speed command signal Vr is a constant value. In the period from time t3 to time t4, the speed command signal Vr is linearly decreased from a constant value to zero, and the speed command signal Vr becomes zero at time t4. When the speed is commanded in this way, from the viewpoint of acceleration, a constant positive acceleration is commanded during the period from time t1 to time t2, and a constant negative acceleration is performed during the period from time t3 to time t4. It was ordered. Furthermore, time t1, time t2, time t3, and time t4 are times when the acceleration changes. That is, when a speed command as shown in FIG. 4A is performed, four acceleration change points at which the acceleration changes are included.

  Further, FIG. 4 shows an example in which mechanical resonance occurs at time t2 when the rotational speed of the electric motor 11 is caused to follow a speed command including such four acceleration change points. Hereinafter, the operation of the dead zone processing unit 20 will be described using such an operation example.

  First, even when the speed command signal Vr until time t1 is zero, there are signal components due to noise and speed detection resolution. For this reason, as shown in FIG. 4C, the signal component Sn is also mixed into the extracted signal x and becomes non-zero. On the other hand, during the period up to time t1, the dead zone control unit 21 sets the threshold value Th0 as the dead zone threshold Th of the dead zone processing unit 20. Since the dead band processing unit 20 does not pass a signal component having an amplitude smaller than the threshold Th0, the signal component Sn having a small amplitude due to noise or speed detection resolution does not pass. That is, as shown in FIG. 4E, the signal component Sn is removed during the period up to time t1, and the extracted vibration signal xe becomes zero. As a result, since the notch control unit 30 does not operate during a period in which the speed command signal Vr continues to be zero as in the time t1, the malfunction of the oscillation suppression function does not occur.

  Next, at the first acceleration change point at time t1, the speed command signal Vr becomes non-zero. The speed command signal Vr increases linearly during the period from time t1 to time t2. Accordingly, since the rotation speed of the electric motor 11 also increases, the speed detection signal Vd also increases during the period from time t1 to time t2, as shown in FIG. 4B. As the vibration extraction filter 17, a high-pass filter or a band-pass filter having a certain degree is used. For this reason, when the speed detection signal Vd such as the first acceleration change point changes, a signal including ringing based on the change is output. That is, as shown in FIG. 4C, immediately after time t1, the extracted signal x newly includes a high-frequency component Sa resulting from the acceleration change of the speed command. On the other hand, since the speed command signal Vr becomes non-zero at time t1, the dead zone control unit 21 sets the threshold value Th1 as the dead zone Th of the dead zone processing unit 20. For this reason, even if a high-frequency component Sa having a larger amplitude than the signal component Sn due to noise or the like is included in the extraction signal x at the first acceleration change point, the threshold Th1 is set larger than the amplitude of the high-frequency component Sa. Therefore, the dead band processing unit 20 removes the high frequency component Sa. As described above, even if an acceleration change occurs in the speed command, the high frequency component Sa caused by the change is removed. Therefore, the notch control unit 30 is not affected by the acceleration change, and the oscillation suppression function does not malfunction.

  Next, in the operation example here, mechanical resonance occurs at the second acceleration change point at time t2. As shown in FIG. 4C, the vibration component Sv due to such mechanical resonance has a larger amplitude than the above-described high-frequency component Sa. That is, since the threshold Th1 is exceeded, the vibration component Sv due to mechanical resonance passes through the dead zone processing unit 20, and as shown in FIG. 4E, the extracted vibration signal xe also includes the vibration component Sv. Become. As a result, the vibration component Sv is supplied to the notch control unit 30, and the oscillation suppression function operates.

  And since the setting of threshold value Th1 is continuing also in the 3rd acceleration change point of the time t3, the influence of the high frequency component Sa resulting from an acceleration change can be suppressed. Further, at the time when the speed command signal Vr changes from non-zero to zero as at time t4, the threshold value Th1 is set for a certain period from that time, so that the high-frequency component Sa such as ringing that occurs immediately after time t4. The influence can also be suppressed.

  For example, even when the extracted vibration signal xe becomes zero as at time t4, there is a possibility that a vibration component having an amplitude equal to or smaller than the threshold Th1 may remain. Even in this case, when the speed command signal Vr becomes zero and a certain time elapses, the dead zone Th is set to Th0 at time t5. Therefore, if the amplitude of the remaining vibration component is larger than the threshold Th0, the dead zone processing unit output xe becomes non-zero again. That is, when the time t5 has passed, a vibration component appears in the extracted vibration signal xe, and the adaptive operation works so as to make it zero. As a result, an operation is performed to suppress a minute vibration component having an amplitude larger than the threshold Th0 and smaller than the threshold Th1, and suppression of mechanical vibration is started after a predetermined time has elapsed from the end of the speed command.

  Since the dead zone processing unit 20 and the dead zone control unit 21 operate as described above, it is possible to suppress the adverse effects of noise and high-frequency components at the time of acceleration change on the oscillation suppression function, thereby ensuring a stable control state.

  Next, the detailed configuration of the notch control unit 30 and the operation of the oscillation suppression function by the notch control unit 30 and the notch filter 15a will be described.

  FIG. 5 is a block diagram showing a main part of the motor control device 10 according to the embodiment of the present invention. FIG. 5 also shows a detailed configuration of the notch control unit 30.

  First, as shown in FIG. 5, the notch control unit 30 includes a notch filter 15 b, a directional filter 31, and a filter coefficient correction unit 32. The notch filter 15b is a filter having the same frequency characteristics as the notch filter 15a, and receives the extracted vibration signal xe and outputs the filtering result signal e1. The direction filter 31 receives the extracted vibration signal xe and outputs a direction detection signal e2. The filter coefficient correction unit 32 corrects the filter coefficients of the notch filter 15a, the notch filter 15b, and the direction filter 31 with the notch control signal cn so that the amplitude of the filtering result signal e1 decreases while referring to the direction detection signal e2. By this modification, the notch frequency is variably controlled. Thus, the extracted vibration signal xe is input to the notch filter 15b and the direction filter 31, and the filtering result signal e1 and the direction detection signal e2 are output, respectively.

  As a characteristic of the notch filter 15b, a predetermined value is given in advance as the notch width, and the depth at the notch center frequency is -∞. For example, a second-order recursive notch filter having a transfer function Hb (s) represented by the following equation is used.

  Here, ωnb is the notch center frequency of the notch filter 15b, and ζb is an attenuation constant. The frequency characteristic is the same as that of the notch filter 15a, and has a characteristic as shown in FIG. As can be seen from FIG. 2, the component of the notch center frequency ωn = ωnb is suppressed, and the gain characteristic is −∞. If the vibration frequency of the extracted vibration signal xe as an input and the notch center frequency ωnb of the notch filter 15b are greatly different, the amplitude of the extracted vibration signal xe is not suppressed, and if they match, the amplitude is suppressed. For this reason, the amplitude of the output of the notch filter 15b increases as the vibration frequency of the extracted vibration signal xe deviates from the notch center frequency ωnb. That is, it can be said that the filtering result signal e1 indicates the degree of deviation between the vibration frequency of the extracted vibration signal xe and the notch center frequency ωnb.

  The direction filter 31 has the same phase in the frequency region lower than the notch center frequency ωn and the opposite phase property in the high frequency region with respect to the frequency characteristic of the notch filter 15b. The directional filter 31 is, for example, a secondary filter having a transfer function Hg (s) expressed by the following equation.

  FIG. 6 is a characteristic diagram showing frequency characteristics of the directional filter 31 of the motor control device 10 according to the embodiment of the present invention. As can be seen from comparison with the frequency characteristics of FIG. 2, the directional filter 31 and the notch filter 15b have the same phase in the frequency region lower than the notch center frequency ωn and the high frequency region when the notch center frequency ωn = ωng. Then, it has frequency phase characteristics of opposite phase.

  FIG. 7 is a block diagram illustrating a configuration example of the filter coefficient correction unit 32 of the electric motor control device 10 according to the embodiment of the present invention. The direction detection signal e2 of the direction filter 31 is input, and the code output unit 101 outputs the code g2 of the direction detection signal e2. In the multiplier 102, the code g2 and the filtering result signal e1 of the notch filter 15b are multiplied. The multiplication result of the multiplier 102 is input to the integrator 103 as a multiplication value q1, and is integrated by the integrator 103. The integration result of the integrator 103 is input to the conversion unit 104 as an integration value q2. Then, the conversion unit 104 converts the integral value q2 into the notch center frequency ωn. This conversion is performed using, for example, an exponential function expressed by the following equation.

  Here, q0 is a preset initial integration value of the integrator 103, and A is a predetermined negative value. Then, the filter coefficient setting unit 105 sets the filter coefficients of the notch filter 15a, the notch filter 15b, and the directional filter 31 according to the input notch center frequency ωn. That is, when the notch center frequency ωn input to the filter coefficient setting unit 105 indicates, for example, the frequency ω0, the filter coefficient setting unit 105 sets the notch center frequency ωna = ω0 of the notch filter 15a and the notch center frequency ωnb of the notch filter 15b. The specific frequencies of the respective filters are set so as to be linked together so that ω0 and the frequency ωng of the directional filter 31 = ω0.

  FIG. 8 is a diagram showing a time change of each data of the filter coefficient correction unit 32 of the motor control device 10 according to the embodiment of the present invention. 8A to 8F show temporal changes of the filtering result signal e1, the direction detection signal e2, the sign g2, the multiplication value q1, the integration value q2, and the notch center frequency ωn, respectively.

  Next, an operation for suppressing oscillation caused by mechanical resonance or the like will be described with reference to FIG.

  First, when the vibration frequency of the vibration component included in the extracted vibration signal xe is different from the notch center frequency ωnb of the notch filter 15b, the notch filter 15b cannot sufficiently suppress the vibration component. For this reason, as shown in FIG. 8A, the extracted vibration signal xe is output as it is as the filtering result signal e1 from the notch filter 15b. Assume that the vibration frequency of the extracted vibration component is lower than the notch center frequency ωnb of the notch filter 15b. In this case, as described above, the directional filter 31 has the same phase characteristic in the frequency region lower than the notch center frequency ωnb with respect to the frequency phase characteristic of the notch filter 15b, and as shown in FIG. The direction detection signal e2 has the same phase as the filtering result signal e1. Further, the code output unit 101 outputs a code g2 of the direction detection signal e2 as shown in FIG. The filtering result signal e1 and the code g2 are multiplied by the multiplier 102, and the multiplier 102 outputs a multiplication value q1 as shown in FIG. In the case of FIG. 8, since the direction detection signal e2 and the filtering result signal e1 are in phase, the multiplication value q1 is non-negative, that is, a positive value. Since the multiplication value q1 is a positive value, the integral value q2 increases as shown in FIG. Since A is a negative predetermined value in (Expression 4), the notch center frequency ωnb changes to a lower frequency as the integral value q2 increases as shown in FIG. It matches the vibration frequency of the component. At this time, since the notch filter 15b suppresses the vibration component from the characteristics, the filtering result signal e1 becomes zero, and the integral value q2 does not change.

  Conversely, when the vibration frequency of the extracted vibration component is higher than the notch center frequency ωnb of the notch filter 15b, the directional filter 31 has an antiphase in the frequency region higher than the notch center frequency ωnb with respect to the frequency phase characteristic of the notch filter 15b. Therefore, the direction detection signal e2 has a phase opposite to that of the filtering result signal e1. In this case, since the multiplication value q1 is non-positive, that is, a negative value, the integral value q2 decreases from (Equation 4). This means that the notch center frequency ωnb changes to a higher frequency. The notch center frequency ωnb increases and eventually matches the vibration frequency of the extracted vibration component. At this time, since the notch filter 15b suppresses the vibration component from its characteristics, the filtering result signal e1 becomes zero and the integral value q2 does not change.

  In this way, the filter coefficient correction unit 32 operates so that the notch center frequency ωnb and the vibration frequency of the vibration component included in the speed detection signal Vd match.

  The directional filter 31 has the same phase in the frequency region lower than the notch center frequency ωnb and the opposite phase in the higher frequency region with respect to the frequency phase property of the notch filter 15b. For this reason, the notch center frequency ωnb always converges to the vibration frequency of the vibration component included in the speed detection signal Vd. Since the notch center frequency ωna of the notch filter 15a and the notch center frequency ωnb of the notch filter 15b are set to be equal, the notch center frequency ωna of the notch filter 15a arranged in the speed control system is also extracted. As a result, the resonance can be automatically suppressed.

  As described above, the electric motor control device of the present invention has a control system that feedback-controls the movement operation of the movable part by the electric motor based on the detection signal and the command signal, and has a notch for the control signal in the control system. A notch filter for attenuating a frequency signal component to be a frequency, an extraction filter for extracting a signal component of a predetermined frequency from the detection signal and outputting it as an extraction signal, and an amplitude that is less than the dead threshold value from the extraction signal according to the command signal A dead zone processing unit that removes signal components and outputs the extracted vibration signal and a notch control unit that controls the notch filter so as to change the notch frequency based on the extracted vibration signal are provided. For this reason, for example, even if a high-frequency component with a large amplitude is mixed in the extraction signal due to a sudden change in the command amount, the extraction signal can be obtained by setting the dead threshold to a value corresponding to the command signal. This high frequency component can be removed. On the other hand, when there is no change in the command signal, for example, the insensitive threshold can be set to the noise level, and only the vibration component based on the mechanical resonance can be supplied to the notch controller with high accuracy. As described above, since the motor control device of the present invention can adaptively set the dead threshold, it is possible to always stably suppress the mechanical resonance without being affected by a change in the command amount such as the speed command. Therefore, according to the motor control device of the present invention, it is possible to constantly suppress the mechanical resonance without being affected by the change in the command amount such as the speed command, and to always keep the stable control state. It is also possible to provide an electric motor control device that controls the movement operation of the load.

  In the present embodiment, an example of the speed control system has been described as the control system. However, the same effect can be obtained by replacing the system configuration with a position control system instead of the speed control system.

  In this embodiment, an example in which the speed detector detects the speed of the movable part of the electric motor has been described. However, a system configuration in which the speed detector detects the speed of the load may be used. Furthermore, the position of the movable part of the electric motor or the load may be detected by a position detector, and the position may be controlled by a position control system. Furthermore, the speed control system equipped with a position detector with a configuration that includes a circuit that differentiates the detection position to obtain the detection speed, and the configuration that includes a circuit that integrates the detection speed to obtain the detection position. It is good also as a position control system provided with the detector. In short, the present invention can be applied to a control system that performs feedback control so that the movement operation of the movable part by the electric motor follows the movement amount such as the commanded position and speed. Further, the moving operation may be a rotating operation of the movable part by an electric motor, a linear operation, or another moving operation.

  In this embodiment, an example in which two threshold values are set as the insensitive threshold value has been described. However, two or more threshold values may be set. For example, three threshold values are prepared, the first threshold value is set as the dead zone threshold value for the acceleration change time of the speed command and the predetermined period from the end of the acceleration change, the speed command is non-zero, and the acceleration of the speed command A configuration may be adopted in which the second threshold value is set during the period excluding the change time and the predetermined period from the end of the acceleration change, and the third threshold value is set during the period excluding the period.

  In the present embodiment, the threshold value is switched based on the value of the speed command signal, but the threshold value may be switched based on the absolute value of the differential value of the speed command signal. In other words, since the amplitude of the high frequency component due to the acceleration change in the speed command is often larger than the amplitude of noise, etc., the speed command is differentiated to obtain the acceleration in the command, and the high frequency component when the acceleration changes greatly is extracted. It is also possible to adopt a configuration in which the signal is removed from the signal.

  In this embodiment, the threshold value is switched based on the value of the speed command signal. However, the threshold value may be switched based on the moving average value of the command signal. Thereby, the bad influence by the threshold value changing frequently can be suppressed.

  In the present embodiment, the motor control device that corrects the filter coefficient of the notch filter and suppresses the resonance vibration has been described. However, the present invention is not limited to the configuration described above, and detects a vibration component. If the motor control device suppresses the resonance vibration by correcting the notch frequency of the notch filter arranged in the speed control or position control system based on the detection result, the same effect can be obtained according to the contents described in the embodiment. Can do.

  The motor control device of the present invention can suppress vibrations with high accuracy with respect to mechanical resonance and the like, and can always control the motor stably. Therefore, the motor such as a component mounting machine or a semiconductor manufacturing apparatus is used. The apparatus is particularly suitable for an electric motor control apparatus that drives an apparatus that causes mechanical resonance.

The block diagram which shows the structure of the electric motor control apparatus in embodiment of this invention Characteristic diagram showing an example of frequency characteristics and phase characteristics of the notch filter of the motor control device The characteristic figure which shows an example of the non-linear characteristic of the dead zone processing part of the same motor control device The figure which shows the operation | movement of a dead zone process part and a dead zone control part of the same motor control device The block diagram which shows the principal part of the same motor control device The characteristic figure which shows the frequency characteristic of the direction filter of the same motor control device The block diagram which shows the structural example of the filter coefficient correction | amendment part of the same motor control apparatus The figure which shows the time change of each data of the filter coefficient correction part of the same motor control device Block diagram showing the configuration of a conventional motor control device

DESCRIPTION OF SYMBOLS 10 Electric motor control apparatus 11 Electric motor 12 Load 13 Speed detector 14 Speed control part 15, 15a, 15b Notch filter 16 Torque control part 17 Vibration extraction filter 20 Dead zone processing part 21 Dead zone control part 30 Notch control part 31 Directional filter 32 Filter coefficient correction Unit 90 Motor control device 101 Code output unit 102 Multiplier 103 Integrator 104 Conversion unit 105 Filter coefficient setting unit

Claims (16)

Based on a detection signal indicating the detected amount of movement of the movable part and a command signal indicating a command amount for instructing the amount of movement of the movable part, the movement operation of the movable part by the electric motor follows the command amount. An electric motor control device having a control system for feedback control as follows:
A notch filter for attenuating a signal component having a frequency to be a notch frequency with respect to a control signal in the control system;
An extraction filter that extracts a signal component of a predetermined frequency from the detection signal and outputs the extracted signal component;
A dead zone processing unit that removes a signal component having an amplitude equal to or less than a dead threshold from the extracted signal according to the command signal, and outputs the extracted vibration signal;
An electric motor control device comprising: a notch control unit that controls the notch filter so as to change the notch frequency based on the extracted vibration signal. A dead zone control unit for notifying the dead zone processing unit of a threshold setting signal based on the command signal;
The motor control apparatus according to claim 1, wherein the dead zone processing unit sets a threshold corresponding to the threshold setting signal as the dead threshold. The electric motor control device according to claim 2, wherein the dead threshold value is set to a plurality of threshold values that have a smallest threshold value as a minimum threshold value and increase according to the magnitude of the threshold value setting signal. The motor control apparatus according to claim 3, wherein the dead zone control unit notifies the dead zone processing unit of the threshold setting signal indicating the magnitude of the command signal. The motor control apparatus according to claim 3, wherein the dead zone control unit notifies the dead zone processing unit of the threshold setting signal indicating a moving average value of the command signal. The motor control apparatus according to claim 3, wherein the dead zone control unit notifies the dead zone processing unit of the threshold setting signal indicating an absolute value of a differential value of the command signal. The threshold value larger than the minimum threshold value is set as the insensitive threshold value during a period when the threshold setting signal is non-zero and a predetermined period from when the threshold setting signal is changed from non-zero to zero. The electric motor control device according to any one of the above. The dead zone processing unit outputs the extracted signal as zero when the amplitude of the extracted signal is equal to or less than the dead threshold, and outputs the input extracted signal as it is when the amplitude of the extracted signal exceeds the dead threshold. The electric motor control device according to claim 1, wherein the electric motor control device is provided. The dead zone processing unit outputs the amplitude as zero when the amplitude of the extraction signal is equal to or less than the dead threshold, and outputs the amplitude of the input extraction signal when the amplitude of the extraction signal exceeds the dead threshold. The motor control device according to claim 1, wherein the motor control device outputs the insensitive threshold value by reducing it. The notch filter is a filter for attenuating a signal of the notch frequency including a signal component of a near frequency corresponding to a notch width with the notch center frequency as a center, the notch frequency being changeable, and the effectiveness of the filter. The motor control device according to claim 1, wherein the invalidity can be switched. The extraction filter is a high-pass filter that extracts a signal component of a predetermined frequency or more included in the detection signal, or a band-pass filter that extracts a signal component within a predetermined frequency bandwidth as a vibration component. The electric motor control apparatus according to 1 or 2. The motor control device according to claim 1, wherein the notch control unit sequentially corrects the notch frequency of the notch filter so that an amplitude of the extracted vibration signal is decreased. 3. The motor control according to claim 1, wherein the insensitive threshold is calculated based on at least one of a gain of the control system, a command unit of the command signal, and a detection unit of the detection signal. apparatus. The motor control device according to claim 1, wherein the control system is a control system that controls either a speed or a position indicating a movement amount of the movable part. The motor control device according to claim 14, wherein the movable part is one of a movable part of the motor and a load driven by the motor. The electric motor control device according to claim 15, wherein the movable portion performs a rotating motion operation.

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