JP6840596B2 - Industrial machinery - Google Patents

Description

Embodiments of the present invention relate to industrial machinery.

Industrial machines such as injection molding machines are equipped with control systems such as motors. The control system is feedback controlled, and a resonance phenomenon may occur in a specific frequency band. The resonance phenomenon may cause the motor to vibrate. In order to suppress such a resonance phenomenon, it is necessary to grasp the frequency characteristics of the control system and set the filter. Normally, in order to grasp the frequency characteristics, white noise is input to the command to the control system, and a board diagram in which the transmission characteristics of each frequency component are arranged is obtained from the comparison between the output waveform and the white noise. The method is used. At this time, it was considered that the frequency characteristics of the control system do not change depending on the rotation angle (hereinafter, simply referred to as an angle) of the motor shaft (that is, the rotor).

However, in reality, the gain of the resonance point and the resonance frequency (center frequency) may change depending on the angle of the motor shaft. For example, a resonance point identified at one angle of the motor shaft may not be identified at all at another angle of the motor shaft. Further, although there is a resonance phenomenon at any angle of the motor shaft, its center frequency may differ depending on the angle. Therefore, even if a filter that suppresses resonance is applied based on a Bode diagram acquired at a certain angle of the motor shaft, there is a problem that the resonance point at another angle of the motor shaft remains unsuppressed.

JP 2015-097462

In order to deal with the above problem, it is conceivable that the user himself rotates the motor shaft and acquires a Bode diagram for each of a plurality of angles of the motor shaft.

However, depending on the installation location of the motor and the size of the motor, it may be difficult for the user to position the motor shaft at a desired angle. Further, if the user himself sets the angle of the motor shaft, the process for acquiring the Bode diagram becomes very complicated, and it takes a long time to acquire the Bode diagram.

Therefore, the present invention has been made to solve these problems, and provides an industrial machine capable of easily obtaining a Bode diagram of a motor shaft at an arbitrary rotation angle.

The industrial machine according to the present embodiment includes a motor that operates an operation target, a servo control unit that controls the motor, and a main control unit that controls the servo control unit so as to set the rotation angle of the shaft of the motor to a predetermined angle. , A frequency characteristic measurement unit that acquires the frequency characteristics and Bode diagram of the servo control unit for multiple rotation angles of the axis, a filter processing unit that suppresses the gain of a part of the gain of the servo control unit, and The main control unit detects a peak whose center frequency or height changes by a predetermined value or more due to a change in the axis angle in the gain of the Bode diagram, and suppresses a part of the gain of the detected peak. Operate the filter processing unit .

The industrial machine may further include a display unit that displays a Bode diagram for a plurality of rotation angles of the shaft.

The main control unit calculates the operating range of the operating target when the axis is rotated 360 °, and even if the acquisition of the frequency characteristics and the Bode diagram is stopped when the operating range exceeds the operating range of the operating target. Good.

The filter processing unit may include a notch filter, and the main control unit may set the cutoff frequency of the notch filter based on the detected peak frequency.

The filter processing unit includes a low-pass filter, and the main control unit may use the lowest frequency of the detected peak as the cutoff frequency of the low-pass filter.

The predetermined angle may be an angle obtained by equally dividing 360 ° into a plurality of equal parts.

The block diagram which shows an example of the structure of the industrial machine 100 by 1st Embodiment. The flow chart which shows an example of the operation of the industrial machine 100 by 1st Embodiment. The graph which shows the measurement result of the board diagram at each division angle of a motor shaft. A graph showing the measurement results of the Bode diagram at each division angle of the motor shaft reacquired after setting the filter. The flow chart which shows an example of the operation of the industrial machine 100 by a modification. The block diagram which shows an example of the structure of the industrial machine 100 by 2nd Embodiment.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. The present embodiment is not limited to the present invention.

(First Embodiment)
FIG. 1 is a block diagram showing an example of the configuration of the industrial machine 100 according to the first embodiment. The industrial machine 100 is, for example, an electric machine such as a machine tool, an injection molding machine, a die casting machine, or an extrusion molding machine. The industrial machine 100 includes a main control unit 10, a position control unit 20, a speed control system 30, a current control unit 40, a motor 50, an encoder 60, an input unit 70, a display 80, and a frequency characteristic measurement unit. It includes 90 and subtractors (calculators) 15 and 32. The position control unit 20, the speed control system 30, and the current control unit 40 are collectively referred to as a "servo control unit".

The main control unit 10 outputs a position command indicating a target position of the motor 50 as a control target. Further, the main control unit 10 converts the division angle obtained by dividing 360 ° into a plurality of positions into a position command, and outputs the position command to the servo control unit (position control unit 20).

Here, the division angle is the rotation angle of the shaft (that is, the rotor) of the motor 50, and is an angle divided into a plurality of angles at an arbitrary angle between 0 ° and 360 °. For example, the division angle may be an angle divided into four by 90 ° between 0 ° and 360 °, such as 0 °, 90 °, 180 °, 270 °, and 360 °. Alternatively, there are eight division angles of 45 ° each between 0 ° and 360 °, such as 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, 315 °, and 360 °. The angle may be divided into. As described above, the division angle is preferably an angle obtained by equally dividing 360 °. However, the division angle may be an angle obtained by dividing 360 ° by an arbitrary angle. For example, the division angle may be arbitrarily divided such as 0 °, 45 °, 90 °, 180 °, 225 °, 270 °, and 360 °. The division angle is the rotation angle of the shaft with a certain position of the shaft of the motor 50 as 0 ° (reference), and can be specified by a position command from the main control unit 10. When the main control unit 10 outputs a position command corresponding to a predetermined division angle to the servo control unit, the servo control unit controls the motor 50 so as to rotate the axis of the motor 50 to a position corresponding to the division angle. To do.

The subtractor 15 calculates the difference between the position command and the actually detected position measurement value, and outputs the difference as a position error.

The position control unit 20 outputs a speed command indicating the target speed of the motor 50 based on the position error from the subtractor 15. The speed command is converted into a torque command in the speed control system 30 and output to the current control unit 40.

The speed control system 30 includes a subtractor 32, a speed control unit 34, and a speed measurement value calculation unit 38. As a result, the speed control system 30 can input the speed command and output the appropriately processed torque command.

The speed measurement value calculation unit 38 calculates the speed measurement value based on the rate of change of the plurality of position measurement values. Alternatively, the speed measurement value calculation unit 38 may convert the position measurement value into the speed measurement value by differentiating the position measurement value. The subtractor 32 calculates the difference between the speed command and the speed measurement value from the speed measurement value calculation unit 38, and outputs the difference as a speed error.

The speed control unit 34 outputs a torque command (current command) for driving the motor 50 based on the speed error from the subtractor 32.

When the current control unit 40 receives a torque command from the speed control system 30, the current control unit 40 supplies a current according to the torque command to the motor 50.

The motor 50 operates (rotates) at the speed indicated by the speed command up to the position indicated by the position command. The rotation of the motor 50 is converted into the operation of a linear mechanism by a ball screw or the like. As a result, the motor 50 operates the operation target.

As described above, the servo control unit controls the motor 50 so that the speed measurement value and torque of the motor 50 follow the speed command and torque command. Further, the servo control unit has a torque command or a current command for rotating the shaft of the motor 50 so as to position the shaft of the motor 50 at each division angle according to the position command corresponding to the division angle set by the main control unit 10. Is output. The main control unit 10 may be a part of the servo control unit, or the servo control unit may be a part of the main control unit 10.

The encoder 60 detects the actual position (rotation angle) of the motor 50. The position measurement value detected by the encoder 60 is transmitted to the main control unit 10, the subtractor 15, and the speed measurement value calculation unit 38.

The input unit 70 is configured so that the user can input the division angle to the main control unit 10. Further, the input unit 70 can input a command (measurement start command) for starting the acquisition of the board diagram of the servo control unit for each division angle. For example, the input unit 70 may be a keyboard, a mouse, or the like. The display 80 as a display unit is configured to be able to display a Bode diagram for each division angle acquired by the frequency characteristic measurement unit 90. The display 80 may be incorporated in the industrial machine 100, or a display of a PC (Personal Computer) external to the industrial machine 100 may be used. The input unit 70 and the display 80 may be a man-machine interface integrally configured as a touch panel display.

The frequency characteristic measurement unit 90 inputs white noise to the servo control unit, measures the frequency characteristic of the servo control unit, and acquires a Bode diagram. The method for measuring the frequency characteristics will be described later. The frequency characteristic measurement unit 90 may be a calculation unit such as a CPU (Central Processor Unit) provided in the industrial machine 100, or may be a computer or the like provided outside. Further, the frequency characteristic measuring unit 90 generates white noise by using a program. The white noise may be generated by the frequency characteristic measurement unit 90, but may be generated by a calculation unit different from the frequency characteristic measurement unit 90.

Here, the main control unit 10 and the servo control unit can rotate the motor shaft so as to be located at a predetermined division angle. As a result, the frequency characteristic measuring unit 90 measures the frequency characteristic of the servo control unit when white noise is input for each of the plurality of division angles, as described with reference to FIG. 2, and the board line. You can get the figure. The industrial machine 100 further includes a storage unit 92 for storing a board diagram for a plurality of division angles, and the acquired board diagram is stored in the storage unit 92.

Next, the operation of the industrial machine 100 according to the present embodiment will be described with reference to FIG.

FIG. 2 is a flow chart showing an example of the operation of the industrial machine 100 according to the present embodiment.

First, the user inputs the measurement start command and the division angle to the input unit 70 (S10). For example, the user inputs 0 °, 90 °, 180 °, and 270 ° as the division angle. When the division angle is an angle obtained by equally dividing 360 ° by a constant angle, the user may input the constant angle (for example, 90 °) or the number of divisions (for example, 4). Upon receiving the input of the measurement start command, the main control unit 10 sets the position of the shaft of the motor 50 at that time to 0 ° (reference). The position of 0 ° may be a preset position. When the preset position is set to 0 °, the main control unit 10 outputs a position command to the position control unit 20 so that the angle of the motor shaft becomes the set position. As a result, the servo control unit rotates the motor shaft and stops it at the set position. The main control unit 10 sets the position where the motor shaft is stopped to 0 °.

Next, the frequency characteristic measuring unit 90 acquires a Bode diagram at a position of 0 ° (S20). For example, the main control unit 10 outputs a speed command of zero speed from the position control unit 20 so as to maintain the angle of the motor shaft at the position of 0 °. The frequency characteristic measuring unit 90 adds the white noise speed command to the speed command output from the position control unit 20 over all frequencies. The speed command to which white noise is added is transmitted to the subtractor 32. At this time, the frequency characteristic measuring unit 90 acquires a speed command to which white noise is added. The speed command to which white noise is added is input from the subtractor 32 to the speed control unit 34, converted into a torque command, and output. The torque command is input to the current control unit 40, and the current according to the torque command is supplied to the motor 50. As a result, the motor shaft vibrates according to white noise around the 0 ° position.

The encoder 60 measures the position of the shaft of the motor 50 in this vibration operation, and transmits the position measurement value to the speed measurement value calculation unit 38. The speed measurement value calculation unit 38 calculates the speed measurement value from the position measurement value and transmits it to the subtractor 32. At this time, the frequency characteristic measurement unit 90 acquires the speed measurement value.

The frequency characteristic measurement unit 90 acquires a Bode diagram from the acquired speed command and speed measurement value by FFT (Fast Fourier Transform) analysis. After acquiring the Bode diagram, the frequency characteristic measuring unit 90 stops applying the speed command of white noise. The Bode diagram acquired as described above is stored in the storage unit 92 as a "characteristic of 0 °".

Next, the main control unit 10 determines whether or not the Bode plots of all the division angles have been acquired (S30). When the Bode plots of all the division angles have not been acquired yet (NO in S30), the main control unit 10 sets the motor shaft by setting the next division angle in the servo control unit (position control unit 20). The board diagram is rotated from the acquired division angle to the next division angle (S40). For example, the main control unit 10 outputs a position command to the position control unit 20 so that the angle of the motor shaft changes from 0 ° to 90 °. As a result, the motor shaft rotates from the 0 ° position and stops at the 90 ° position.

Next, the frequency characteristic measurement unit 90 acquires a Bode diagram (S50). The frequency characteristic measuring unit 90 acquires the Bode diagram at the 90 ° position by the same method as in the case of the 0 ° position. The acquired Bode diagram is stored by the storage unit 92 as a "characteristic of 90 °".

The industrial machine 100 repeats steps S40 and S50 until it further obtains the "180 ° characteristic" and "270 ° characteristic" Bode plots. When the Bode plots of all the division angles are acquired (YES in S30), the main control unit 10 and the servo control unit stop all the commands to the motor 50. Further, the display 80 displays the measurement completion notification, and displays the board diagram at all the division angles stored in the storage unit 92 as a list together with the input values of the division angles (S60). The display 80 may display the Bode diagram each time the board diagram of each division angle is acquired. Specific examples of the Bode diagram will be described with reference to FIGS. 3 (A) to 3 (D).

As described above, the industrial machine 100 according to the present embodiment rotates the motor shaft so as to be located at a predetermined division angle, and acquires a Bode diagram for each of the plurality of division angles. Since the rotation of the motor shaft and the acquisition of the Bode diagram are automatically performed, the industrial machine 100 can easily acquire the Bode diagram for each angle of the motor shaft. Further, even after applying the filter or the like, the industrial machine 100 can easily reacquire the Bode diagram, so that there is little time and labor loss.

Further, the industrial machine 100 according to the present embodiment displays each board diagram for a plurality of division angles. This allows the user to consider the Bode plot of each division angle in a list. In addition, the user is more likely to notice the movement of the resonance point that he did not notice. As a result, the user can devise the optimum resonance countermeasure while looking at the board diagram of a plurality of division angles.

3 (A) to 3 (D) are graphs showing the measurement results of the Bode diagram at each division angle of the motor shaft. L1 and L2 indicate the gain characteristic (amplitude (dB)) and the phase characteristic (phase delay of the speed measurement value with respect to the speed command), respectively. The vertical axis shows the gain characteristic and the phase characteristic, and the horizontal axis shows the frequency. FIG. 3 (A) is a Bode diagram “characteristics of 0 °” when the motor shaft angle is 0 °, and FIG. 3 (B) is a Bode diagram “90 ° characteristics” when the motor shaft angle is 90 °. 3 (C) is a Bode diagram "180 ° characteristics" when the motor shaft angle is 180 °, and FIG. 3 (D) is a Bode diagram "180 ° characteristics" when the motor shaft angle is 270 °. "Characteristics of 270 °".

The “0 ° characteristic” and “90 ° characteristic” shown in FIGS. 3 (A) and 3 (B) indicate that a resonance point exists at 700 Hz to 800 Hz. On the other hand, in the "characteristics of 180 °" and "characteristics of 270 °" shown in FIGS. 3 (C) and 3 (D), no resonance point is confirmed at 700 Hz to 800 Hz. The user can notice the existence of the resonance point by looking at the Bode diagram of each division angle even when the resonance point is not confirmed at a certain division angle. As a result, the user can take measures against resonance by setting a filter for the resonance point. For example, if only FIG. 3 (C) or FIG. 3 (D) is referred to, the user determines that it is not necessary to set the filter. However, as in this embodiment, by referring not only to FIGS. 3 (C) and 3 (D) but also to FIGS. 3 (A) and 3 (B), the user can use a notch filter from 700 Hz to 800 Hz. Can be set. In this way, the user can easily grasp the resonance point of the motor shaft at an arbitrary division angle (rotation angle) and set the filter for the frequency corresponding to the resonance point. As a result, the industrial machine 100 can perform stable servo control in a wide frequency band. The gain characteristics shown in FIGS. 3 (A) to 3 (D) and 4 (A) to 4 (D) exceed 0 dB at 200 Hz or less, but resonance does not occur at 200 Hz or less. This is because resonance does not occur at a frequency of 300 Hz to 400 Hz or less where the phase characteristics are inverted.

4 (A) to 4 (D) are graphs showing the measurement results of the Bode diagram at each division angle of the motor shaft reacquired after setting the filter. The industrial machine 100 performs filtering in the speed control system 30. The user may operate the filtering unit. After the filtering process, the industrial machine 100 reacquires the Bode diagram for each of the plurality of division angles. In FIGS. 4 (A) and 4 (B), the peak at the resonance point of 700 Hz to 800 Hz confirmed in FIGS. 3 (A) and 3 (B) is an arbitrary value of the gain characteristic (for example, -10 dB). It is shown that it was suppressed by filtering so as not to exceed. In this way, since the industrial machine 100 can easily reacquire the Bode diagram, the user can confirm the board diagram after the filtering process, and further, the filter setting and the confirmation of the Bode diagram. By repeating and, the user can also consider more appropriate filtering conditions.

(Modification example)
The industrial machine 100 according to this modification is different from the industrial machine 100 according to the first embodiment in that it includes a safety device (interlock function) for the motor 50. The main control unit 10 rotates the motor shaft so as to be located at each division angle in order to acquire a Bode diagram. If the operating target of the motor 50 exceeds the operable range due to the rotation of the motor shaft, the operating target may collide with another fixed member. As a result, damage to the operating target, excessive load on the motor 50, and the like may occur. Therefore, the industrial machine 100 has an interlock function that calculates the operating range of the operating target and blocks the operation of the motor 50 when the operating range exceeds the operating range of the operating target.

Since the basic configuration of the industrial machine 100 according to this modification is the same as the configuration of the industrial machine 100 according to the first embodiment, detailed description thereof will be omitted.

FIG. 5 is a flow chart showing an example of the operation of the industrial machine 100 according to this modification.

After step S10 similar to FIG. 2, the encoder 60 measures the actual position of the operation target and transmits the position measurement value of the operation target to the main control unit 10. As a result, the main control unit 10 acquires the position measurement value of the operation target when the measurement start command is received (S11). Next, the main control unit 10 calculates the range in which the operation target moves when the motor shaft is rotated so as to be located at a predetermined division angle (S12). At this time, the main control unit 10 calculates the operating range when rotated by at least the maximum division angle. For example, if the input split angles are 0 °, 90 °, 180 °, 270 °, the motor shaft will rotate 270 ° to obtain the Bode plot. In this case, the main control unit 10 calculates the operating range of the operating target when the motor shaft rotates from 0 ° to 270 °. Of course, the main control unit 10 may calculate the operating range of the operating target when the motor shaft rotates (one rotation) from 0 ° to 360 °.

Next, the main control unit 10 determines whether the calculated operating range exceeds the operating range of the operating target (S13). When the operating range exceeds the operable range (YES in S13), the main control unit 10 stops the acquisition of the frequency characteristics and the Bode diagram in step S20 by the interlock function, and prevents the operation of the motor 50 (S14). ). Further, the display 80 displays an error and indicates to the user that the operating range exceeds the operable range (S14). In this case, the user releases the interlock and moves the operation target so as not to exceed the operable range (S15). For example, the user confirms a position where the operating range does not exceed the operable range, and moves the operating target to that position. The user manually rotates the motor shaft in the direction opposite to the direction in which the motor shaft rotates from one division angle to the next division angle. Alternatively, the user may output a position command from the main control unit 10 so that the operation target moves in the direction opposite to the operation direction indicated in the operation range. After that, steps S10 to S13 are executed. If the operating range does not exceed the operable range in step S13 (NO in S13), steps S20 to S60 are executed. The operation after step S20 is the same as that of the industrial machine 100 according to the first embodiment.

As described above, the industrial machine 100 according to the present modification calculates the range in which the operation target moves when the motor shaft is rotated so as to be located at a predetermined division angle, and the operation range determines the movable range of the operation target. If it exceeds, the operation of the motor 50 is blocked. As a result, the industrial machine 100 can prevent the operating object from colliding with other members beyond the operable range. Therefore, the industrial machine 100 can suppress damage to the operating object, excessive load on the motor 50, and the like. Further, the industrial machine 100 according to the present modification can obtain the same effect as the industrial machine 100 according to the first embodiment.

(Second Embodiment)
In the industrial machine 100 according to the first embodiment, the user takes measures against resonance such as a filter, whereas in the industrial machine 100 according to the second embodiment, the industrial machine 100 automatically performs the filter processing regardless of the user. Do.

FIG. 6 is a block diagram showing an example of the configuration of the industrial machine 100 according to the second embodiment. The industrial machine 100 further includes a filter processing unit 95. Since other configurations are the same as those of the first embodiment, detailed description thereof will be omitted.

The filter processing unit 95 filters the torque command output by the speed control unit 34. As a result, the filter processing unit 95 operates so as to suppress a part of the gain characteristic of the servo control unit. The filter included in the filter processing unit 95 is, for example, a notch filter or a low-pass filter. The filter processing unit 95 may be a part of the main control unit 10 or the servo control unit.

Next, the operation of the filtering process will be described.

First, the main control unit 10 receives the board diagrams of all the division angles from the frequency characteristic measuring unit 90 after acquiring the board diagrams of all the division angles (YES in S30 of FIG. 2). The main control unit 10 detects the peak of the resonance point whose gain characteristic (height) is equal to or higher than a predetermined value in the Bode diagram of all the division angles.

The main control unit 10 holds in advance the ideal waveform of the gain characteristic without a peak as data, and sets the gain characteristic of the ideal waveform for each gain characteristic of "0 ° characteristic" to "270 ° characteristic". Calculate the absolute value of the difference. The main control unit 10 detects a frequency band in which the absolute value of the difference in gain characteristics is equal to or greater than a predetermined value, determines that the peak in this frequency band is a resonance point, and detects it as a frequency band for setting a filter.

For example, as shown in FIG. 3A, the peak detection of the “characteristic of 0 °” will be described with a predetermined value of 10 dB. First, the main control unit 10 calculates the difference between the gain characteristic of the “0 ° characteristic” and the gain characteristic of the ideal waveform. At this time, the absolute value of the difference is a predetermined value, for example, the frequency band exceeding 10 dB is 700 Hz to 800 Hz. Therefore, in the "characteristic of 0 °", a peak having a vertex of about −5 dB is detected. Since the gain characteristics of 700 Hz or less and 800 Hz or more are almost the same as the ideal waveform, the peak for setting the filter is not detected at 700 Hz or less and 800 Hz or more. On the other hand, in the "180 ° characteristic" shown in FIG. 3C, the absolute value of the difference between the gain characteristic of 400 Hz to 500 Hz and the gain characteristic of the ideal waveform does not exceed 10 dB. Further, the gain characteristics of 400 Hz or less and 500 Hz or more are almost the same as the ideal waveform. Therefore, in the "characteristic of 180 °", the peak that sets the filter is not detected. The main control unit 10 calculates the absolute value of this difference for all combinations of division angles of "characteristics of 0 °" to "characteristics of 270 °". As a result, the main control unit 10 detects peaks at 700 Hz to 800 Hz in the “0 ° characteristic” shown in FIG. 3 (A) and the “90 ° characteristic” shown in FIG. 3 (B).

The above shows an example of peak detection based on the difference in gain characteristics, but the present invention is not limited to this, and a plurality of detection methods may be used or may be used in combination.

The main control unit 10 outputs the detected peak information (for example, peak height, half width, etc.) to the filter processing unit 95. As a result, the main control unit 10 operates the filter processing unit 95 so as to suppress a part of the gain characteristic of the detected peak.

Next, the details of the filter setting method by the main control unit 10 will be described.

When the filter processing unit 95 includes a notch filter, the main control unit 10 sets a specific center frequency (cutoff frequency) in the filter processing unit 95. When the filter processing unit 95 can set a plurality of notch filters, the main control unit 10 sets the frequencies corresponding to the plurality of peaks as the cutoff frequencies of the notch filters, and sets the filter processing units 95 for each of those frequencies. Make it work.

For example, the main control unit 10 operates the filter processing unit 95 with the center frequency of one peak of 700 Hz to 800 Hz of the “characteristic of 0 °” shown in FIG. 3A as the cutoff frequency of the notch filter. Further, the main control unit 10 operates the filter processing unit 95 with the center frequency of one peak of 700 Hz to 800 Hz of the “characteristic of 90 °” shown in FIG. 3 (B) as the cutoff frequency of the notch filter. In this case, the main control unit 10 operates the filter processing unit 95 for a total of two frequencies.

When the filter processing unit 95 can set only one notch filter, the main control unit 10 operates the filter processing unit 95 with the average value of the highest frequency and the lowest frequency at the detected peak as the cutoff frequency of the notch filter. You may.

For example, the main control unit 10 has the center frequency of the peak between 700 Hz and 800 Hz of the “0 ° characteristic” shown in FIG. 3 (A) and 700 Hz to 700 Hz of the “90 ° characteristic” shown in FIG. 3 (B). The average value (for example, 750 Hz) with the center frequency of the peak of 800 Hz is calculated. The main control unit 10 operates the filter processing unit 95 with the calculated average frequency (for example, 750 Hz) as the cutoff frequency of the notch filter. At this time, the main control unit 10 may set the bandwidth of the notch filter so that all the detected peaks are equal to or less than a predetermined gain characteristic value (for example, −10 dB).

Further, when the filter processing unit 95 can set only one notch filter, the main control unit 10 may operate the filter processing unit 95 with the frequency of the highest peak in the detected peak as the cutoff frequency of the notch filter.

For example, the main control unit 10 compares the peak heights of the center frequencies of the “0 ° characteristic” shown in FIG. 3 (A) and the “90 ° characteristic” shown in FIG. 3 (B), and has the highest peak. The filter processing unit 95 is operated with the center frequency of the notch filter as the cutoff frequency of the notch filter.

On the other hand, when the filter processing unit 95 includes a low-pass filter, the main control unit 10 sets the cutoff frequency in the filter processing unit 95. The main control unit 10 operates the filter processing unit 95 with the lowest center frequency of the detected peak as the cutoff frequency.

For example, the main control unit 10 compares the center frequencies of the “0 ° characteristic” shown in FIG. 3 (A) and the “90 ° characteristic” shown in FIG. 3 (B), and sets the lower center frequency of the low-pass filter. The filter processing unit 95 is operated as the cutoff frequency.

As described above, the industrial machine 100 according to the second embodiment includes the filter processing unit 95 that suppresses a part of the gain characteristic of the servo control unit. Further, the industrial machine 100 detects a peak in which the center frequency or the height changes due to a change in the rotation angle of the motor shaft in the gain characteristic of the Bode diagram. Further, the industrial machine 100 operates the filter processing unit 95 so as to suppress a part of the gain characteristic of the detected peak. As a result, the industrial machine 100 can detect the gain characteristic that changes depending on the rotation angle of the motor shaft and automatically perform the filter processing. As a result, the user's trouble can be saved.

Further, the industrial machine 100 according to the second embodiment can obtain the same effect as the industrial machine 100 according to the first embodiment. Further, a modification of the first embodiment may be applied to the industrial machine 100 according to the second embodiment.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

100 industrial machinery, 10 main control unit, 20 position control unit, 30 speed control system, 40 current control unit, 50 motor, 60 encoder, 70 input unit, 80 display, 90 frequency characteristic measurement unit, 92 storage unit, 95 filter processing Department

Claims (6)

The motor that operates the operating target and
A servo control unit that controls the motor and
A main control unit that controls the servo control unit so as to set the rotation angle of the motor shaft to a predetermined angle,
A frequency characteristic measuring unit that acquires the frequency characteristics and a Bode diagram of the servo control unit for a plurality of rotation angles of the shaft, and a frequency characteristic measuring unit.
A filter processing unit that suppresses the gain of a part of the frequency band of the gain of the servo control unit is provided .
The main control unit detects a peak in which the center frequency or height changes to a predetermined value or more due to a change in the angle of the axis in the gain of the Bode diagram, and suppresses a part of the gain of the detected peak. An industrial machine that operates the filter processing unit as described above. The industrial machine according to claim 1, further comprising a display unit for displaying the Bode diagram for a plurality of rotation angles of the shaft. The main control unit calculates the operating range of the operating target when the axis is rotated by 360 °, and when the operating range exceeds the operating range of the operating target, the frequency characteristic and the Bode diagram. The industrial machine according to claim 1 or 2, which suspends the acquisition of the above. The filter processing unit includes a notch filter.
The industrial machine according to any one of claims 1 to 3, wherein the main control unit sets a cutoff frequency of the notch filter based on the detected frequency of the peak. The filter processing unit includes a low-pass filter.
The industrial machine according to any one of claims 1 to 3, wherein the main control unit uses the lowest frequency of the detected peak as the cutoff frequency of the low-pass filter. The industrial machine according to any one of claims 1 to 5 , wherein the predetermined angle is an angle obtained by equally dividing 360 ° into a plurality of equal parts.

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