JP2018169765A - Industrial machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrial machine capable of easily obtaining a Bode diagram of a motor shaft at an arbitrary rotation angle.SOLUTION: An industrial machine 100 includes: a motor 50 for operating an operation target; a servo control unit for controlling the motor 50; a main control unit 10 for controlling the servo control unit so as to set a rotation angle of a shaft of the motor 50 to a predetermined angle; and a frequency characteristic measuring unit 90 for acquiring frequency characteristics and a Bode diagram of the servo control unit for a plurality of rotation angles of the shaft.SELECTED DRAWING: Figure 1

Description

  Embodiments according to the present invention relate to industrial machinery.

  Industrial machines such as injection molding machines are equipped with a control system such as a motor. 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 a filter. Usually, in order to grasp the frequency characteristics, white noise is input to the command to the control system, and a Bode diagram in which the transfer characteristics of each frequency component are arranged is obtained by comparing the output waveform with the white noise. The method is used. At this time, it has been considered that the frequency characteristic of the control system does not change depending on the rotation angle (hereinafter also simply referred to as an angle) of the motor shaft (ie, 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 confirmed at one angle of the motor shaft may not be confirmed at all at another angle of the motor shaft. Further, although there is a resonance phenomenon at any angle of the motor shaft, the center frequency may vary depending on the angle. Therefore, even when a filter that suppresses resonance based on a Bode diagram acquired at a certain angle of the motor shaft is applied, there is a problem that resonance points at other angles of the motor shaft remain unsuppressed.

Japanese Patent Laying-Open No. 2015-097462

  In order to cope with the above problem, it is conceivable that the user himself / herself 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 himself to position the motor shaft at a desired angle. Furthermore, if the user himself / herself sets the angle of the motor shaft, the process for acquiring the board diagram becomes very complicated, and it takes a long time to acquire the board diagram.

  Accordingly, the present invention has been made to solve these problems, and provides an industrial machine that can easily obtain 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. And a frequency characteristic measuring unit that obtains a frequency characteristic of the servo control unit and a Bode diagram for a plurality of rotation angles of the shaft.

  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 operation range of the operation target when the axis is rotated 360 °, and if the operation range exceeds the operable range of the operation target, even if acquisition of the frequency characteristics and the Bode diagram is stopped Good.

  The industrial machine may further include a filter processing unit that suppresses a gain in a part of the frequency band among the gains of the servo control unit.

  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 axis angle in the Bode diagram gain, and performs a filtering process to suppress a part of the detected peak gain. The unit may be operated.

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

  The filter processing unit may include a low-pass filter, and the main control unit may set the lowest frequency in 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 angles.

The block diagram which shows an example of a structure of the industrial machine 100 by 1st Embodiment. The flowchart which shows an example of operation | movement of the industrial machine 100 by 1st this embodiment. The graph which shows the measurement result of the Bode diagram in each division angle of a motor axis. The graph which shows the measurement result of the Bode diagram in each division angle of the motor axis re-acquired after filter setting. The flowchart which shows an example of operation | movement of the industrial machine 100 by a modification. The block diagram which shows an example of a structure of the industrial machine 100 by 2nd Embodiment.

  Embodiments according to the present invention will be described below with reference to the drawings. This embodiment does not limit the present invention.

(First embodiment)
FIG. 1 is a block diagram illustrating an example of a configuration of an industrial machine 100 according to the first embodiment. The industrial machine 100 is 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. 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 the 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 position commands, and outputs the position commands to the servo control unit (position control unit 20).

  Here, the division angle is the rotation angle of the shaft of the motor 50 (that is, the rotor), and is an angle divided into a plurality of arbitrary angles between 0 ° and 360 °. For example, the division angle may be an angle obtained by dividing the range from 0 ° to 360 ° into four portions of 90 °, such as 0 °, 90 °, 180 °, 270 °, and 360 °. Alternatively, there are eight division angles of 45 ° between 0 ° and 360 °, such as 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, 315 °, 360 °. The angle may be divided into two. Thus, 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 a rotation angle of the shaft with a certain position of the shaft of the motor 50 being 0 ° (reference), and can be designated 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 to rotate the shaft of the motor 50 to a position corresponding to the division angle. To do.

  The subtracter 15 calculates a 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 subtracter 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 subtracter 32, a speed control unit 34, and a speed measurement value calculation unit 38. Thus, the speed control system 30 can input a speed command and output a properly processed torque command.

  The speed measurement value calculation unit 38 calculates the speed measurement value based on the change rate of the plurality of position measurement values. Alternatively, the speed measurement value calculator 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 calculator 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 receiving 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. Thereby, the motor 50 operates the operation target.

  As described above, the servo control unit controls the motor 50 so that the speed measurement value or torque of the motor 50 follows the speed command or torque command. In addition, the servo control unit performs 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 a division angle to the main control unit 10. In addition, the input unit 70 allows a user to input a command (measurement start command) for starting acquisition of a Bode diagram of the servo control unit for each division angle. For example, the input unit 70 may be a keyboard or a mouse. The display 80 serving 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) outside 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, and obtains a measurement of the frequency characteristic of the servo control unit and a Bode diagram. A method for measuring 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 provided outside. The frequency characteristic measuring unit 90 generates white noise 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 positioned at a predetermined division angle. Thereby, the frequency characteristic measuring unit 90 measures the frequency characteristic of the servo control unit when white noise is input for each of a plurality of division angles, as described with reference to FIG. A figure can be obtained. The industrial machine 100 further includes a storage unit 92 that stores a Bode diagram for a plurality of division angles, and the acquired Bode 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 flowchart showing an example of the operation of the industrial machine 100 according to the present embodiment.

  First, the user inputs a measurement start command and a 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 (eg, 90 °) or the number of divisions (eg, 4). Upon receiving 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 set to 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. Accordingly, 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 stops 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 a position of 0 °. The frequency characteristic measuring unit 90 adds the speed command of white noise over the entire frequency to the speed command output from the position control unit 20. The speed command to which the white noise is added is transmitted to the subtracter 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 the 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 a current according to the torque command is supplied to the motor 50. As a result, the motor shaft performs a vibration operation according to white noise with the position of 0 ° as the center.

  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 a 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 a speed measurement value.

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

  Next, the main control unit 10 determines whether or not the Bode diagrams for all the split angles have been acquired (S30). When the Bode diagrams of all the split angles have not been acquired yet (NO in S30), the main control unit 10 sets the next split angle in the servo control unit (position control unit 20), so that the motor axis is set. The board diagram is rotated from the obtained 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 becomes a position 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 measurement unit 90 acquires a Bode diagram at the 90 ° position by the same method as that at the 0 ° position. The acquired Bode diagram is stored in the storage unit 92 as “90 ° characteristics”.

  The industrial machine 100 repeats steps S40 and S50 until the Bode diagrams of “180 ° characteristic” and “270 ° characteristic” are acquired. When the Bode diagrams of all the split angles are acquired (YES in S30), the main control unit 10 and the servo control unit stop all the commands for the motor 50. Further, the display 80 displays a measurement completion notification, and displays the Bode diagrams for all 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 every time the Bode diagram of each division angle is acquired. A specific example of the Bode diagram will be described with reference to FIGS.

  As described above, the industrial machine 100 according to the present embodiment rotates the motor shaft so as to be positioned 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 board diagram are automatically performed, the industrial machine 100 can easily acquire the board diagram for each angle of the motor shaft. Further, even after applying a filter or the like, the industrial machine 100 can easily re-obtain the Bode diagram, so that there is little time and labor loss.

  Furthermore, the industrial machine 100 according to the present embodiment displays each Bode diagram for a plurality of division angles. Thereby, the user can consider the Bode diagram of each division angle in a list. Furthermore, the user can easily notice the movement of the resonance point that he / she did not notice. Thus, the user can devise an optimal resonance countermeasure while viewing the Bode 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 gain characteristics (amplitude (dB)) and phase characteristics (phase delay of speed measurement value with respect to speed command), respectively. The vertical axis represents gain characteristics and phase characteristics, and the horizontal axis represents frequency. 3A is a Bode diagram “0 ° characteristic” when the motor shaft angle is 0 °, and FIG. 3B is a Bode diagram “90 ° characteristic when the motor shaft angle is 90 °. 3 (C) is a Bode diagram “180 ° characteristic” when the motor shaft angle is 180 °, and FIG. 3 (D) is a Bode diagram when the motor shaft angle is 270 °. 270 ° characteristic ”.

  “0 ° characteristic” and “90 ° characteristic” shown in FIGS. 3A and 3B indicate that a resonance point exists in 700 Hz to 800 Hz. On the other hand, no resonance point is observed in the range of 700 Hz to 800 Hz in the “180 ° characteristic” and “270 ° characteristic” shown in FIGS. Even if the resonance point is not confirmed at a certain division angle, the user can notice the existence of the resonance point by looking at the Bode diagram of each division angle. Thereby, the user can take a countermeasure against resonance by setting a filter for the resonance point. For example, if only FIG. 3C or FIG. 3D is referred to, the user determines that it is not necessary to set a filter. However, as in the present embodiment, by referring not only to FIG. 3C and FIG. 3D but also to FIG. 3A and FIG. Can be set. Thus, the user can easily grasp the resonance point of the motor shaft at an arbitrary division angle (rotation angle) and set a 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. Although the gain characteristics shown in FIGS. 3A to 3D and FIGS. 4A to 4D exceed 0 dB at 200 Hz or less, resonance does not occur at 200 Hz or less. This is because resonance does not occur below the frequency of 300 Hz to 400 Hz where the phase characteristics are inverted.

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

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

  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, and thus detailed description thereof is omitted.

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

  After step S <b> 10 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. Thereby, 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 a range in which the operation target moves when the motor shaft rotates so as to be positioned at a predetermined division angle (S12). At this time, the main control unit 10 calculates an operation range at least when the main control unit 10 is rotated by the maximum division angle. For example, if the input split angle is 0 °, 90 °, 180 °, 270 °, the motor shaft will rotate 270 ° for acquisition of the Bode diagram. In this case, the main control unit 10 calculates the operation range of the operation target when the motor shaft rotates from 0 ° to 270 °. Of course, the main controller 10 may calculate the operation range of the operation target when the motor shaft rotates from 0 ° to 360 ° (one rotation).

  Next, the main control unit 10 determines whether the calculated operation range exceeds the operable range of the operation 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 displays 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 operation range does not exceed the operable range, and moves the operation target to that position. The user manually rotates the motor shaft in a direction opposite to the direction in which the motor shaft rotates from a certain 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 a direction opposite to the operation direction indicated in the operation range. Thereafter, 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 operations after step S20 are the same as those 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 rotates so as to be positioned at the predetermined division angle, and the operation range indicates the operable range of the operation target. If it exceeds, the operation of the motor 50 is blocked. Thereby, the industrial machine 100 can suppress the operation target from colliding with other members beyond the operable range. Therefore, the industrial machine 100 can suppress damage to the operation target, excessive load on the motor 50, and the like. In addition, the industrial machine 100 according to the present modification can obtain the same effects as the industrial machine 100 according to the first embodiment.

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

  FIG. 6 is a block diagram illustrating 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 is omitted.

  The filter processing unit 95 performs a filter process on the torque command output from the speed control unit 34. Thereby, the filter processing unit 95 operates 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 filter process will be described.

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

  The main control unit 10 holds in advance an ideal waveform having a gain characteristic without a peak as data, and sets the gain characteristic of the ideal waveform for each of the gain characteristics 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 gain characteristic difference is equal to or greater than a predetermined value, determines a peak in this frequency band as 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 “0 ° characteristic” will be described with a predetermined value of 10 dB. First, the main control unit 10 calculates the difference between the gain characteristic of “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 “0 ° characteristic”, a peak having a peak of about −5 dB is detected. Since the gain characteristics of 700 Hz or less and 800 Hz or more are substantially 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. Furthermore, the gain characteristics of 400 Hz or less and 500 Hz or more are almost the same as the ideal waveform. Therefore, in the “180 ° characteristic”, a peak for setting a filter is not detected. The main control unit 10 calculates the absolute value of the difference for all combinations of division angles from “0 ° characteristic” to “270 ° characteristic”. Thereby, the main control unit 10 detects a peak at 700 Hz to 800 Hz in the “0 ° characteristic” shown in FIG. 3A and the “90 ° characteristic” shown in FIG.

  In addition, although the above has shown the example of the detection of the peak based on the difference of a gain characteristic, it is not limited to this, A several detection method may be used and you may use it further combining.

  The main control unit 10 outputs the detected peak information (for example, peak height, half-value width, etc.) to the filter processing unit 95. Thereby, 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 cutoff frequencies of the notch filters, and sets the filter processing unit 95 to each of those frequencies. Make it work.

  For example, the main control unit 10 operates the filter processing unit 95 using the center frequency of one peak of 700 Hz to 800 Hz of the “0 ° characteristic” shown in FIG. 3A as the cutoff frequency of the notch filter. Further, the main control unit 10 operates the filter processing unit 95 using the center frequency of one peak of 700 Hz to 800 Hz of the “90 ° characteristic” shown in FIG. 3B 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 using the average value of the highest frequency and the lowest frequency in the detected peak as the cutoff frequency of the notch filter. May be.

  For example, the main control unit 10 has a peak center frequency between 700 Hz and 800 Hz of “0 ° characteristic” shown in FIG. 3A, and 700 Hz to “90 ° characteristic” shown in FIG. An 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 using the calculated average frequency (for example, 750 Hz) as the cut-off frequency of the notch filter. At this time, the main control unit 10 may set the bandwidth of the notch filter so that all 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 using the frequency of the highest peak among the detected peaks 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. 3A and the “90 ° characteristic” shown in FIG. The filter processing unit 95 is operated using 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 a cutoff frequency in the filter processing unit 95. The main control unit 10 operates the filter processing unit 95 using the lowest center frequency in the detected peak as a cutoff frequency.

  For example, the main control unit 10 compares the center frequencies of the “0 ° characteristic” shown in FIG. 3A and the “90 ° characteristic” shown in FIG. The filter processing unit 95 is operated as a cutoff frequency.

  Thus, the industrial machine 100 by 2nd Embodiment is provided with the filter process part 95 which suppresses a part of gain characteristic of a servo control part. Further, the industrial machine 100 detects a peak in which the center frequency or the height changes due to the change in the rotation angle of the motor shaft in the gain characteristic of the Bode diagram. Furthermore, the industrial machine 100 operates the filter processing unit 95 so as to suppress a part of the gain characteristic of the detected peak. Thereby, the industrial machine 100 can detect the gain characteristic which changes with the rotation angle of a motor shaft, and can perform a filter process automatically. As a result, the user's trouble can be saved.

  Further, the industrial machine 100 according to the second embodiment can obtain the same effects as the industrial machine 100 according to the first embodiment. Furthermore, you may apply the modification of 1st Embodiment to the industrial machine 100 by 2nd Embodiment.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example 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 spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents 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 Part

Claims (8)

A motor for operating the operation target;
A servo control unit for controlling the motor;
A main control unit that controls the servo control unit to set a rotation angle of the shaft of the motor to a predetermined angle;
An industrial machine comprising: a frequency characteristic measuring unit that obtains a frequency characteristic and a Bode diagram of the servo control unit for a plurality of rotation angles of the shaft.   The industrial machine according to claim 1, further comprising a display unit that displays the Bode diagram for a plurality of rotation angles of the shaft.   The main control unit calculates an operation range of the operation target when the shaft is rotated 360 °, and the frequency characteristic and the Bode diagram are calculated when the operation range exceeds the operable range of the operation target. The industrial machine according to claim 1, wherein the acquisition of the industrial machine is stopped.   The industrial machine according to any one of claims 1 to 3, further comprising a filter processing unit that suppresses a gain in a part of a frequency band among the gains of the servo control unit.   The main control unit detects a peak in which the center frequency or the 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 detected gain of the peak. The industrial machine according to claim 4, wherein the filter processing unit is operated as described above. The filter processing unit includes a notch filter,
The industrial machine according to claim 5, wherein the main control unit sets a cutoff frequency of the notch filter based on the detected peak frequency. The filter processing unit includes a low-pass filter,
The industrial machine according to claim 5, wherein the main control unit sets the lowest frequency at the detected peak as a cutoff frequency of the low-pass filter.   The industrial machine according to any one of claims 1 to 7, wherein the predetermined angle is an angle obtained by equally dividing 360 ° into a plurality of angles.

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