WO2023067683A1 - Control device of machine tool - Google Patents

Control device of machine tool Download PDF

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Publication number
WO2023067683A1
WO2023067683A1 PCT/JP2021/038569 JP2021038569W WO2023067683A1 WO 2023067683 A1 WO2023067683 A1 WO 2023067683A1 JP 2021038569 W JP2021038569 W JP 2021038569W WO 2023067683 A1 WO2023067683 A1 WO 2023067683A1
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Prior art keywords
speed
command
fluctuation
clamp
spindle
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PCT/JP2021/038569
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French (fr)
Japanese (ja)
Inventor
航希 及川
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ファナック株式会社
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Priority to PCT/JP2021/038569 priority Critical patent/WO2023067683A1/en
Publication of WO2023067683A1 publication Critical patent/WO2023067683A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q15/00—Automatic control or regulation of feed movement, cutting velocity or position of tool or work
    • B23Q15/007—Automatic control or regulation of feed movement, cutting velocity or position of tool or work while the tool acts upon the workpiece
    • B23Q15/12—Adaptive control, i.e. adjusting itself to have a performance which is optimum according to a preassigned criterion
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

  • the present invention relates to a control device for machine tools.
  • chatter vibration When cutting with a machine tool, chatter vibration may occur continuously between the tool and the workpiece. Chatter vibration is classified into forced chatter vibration and self-excited chatter vibration according to the factors of vibration generation. Forced chatter vibration is generated under the influence of a forced vibration source, and self-excited chatter vibration is generated without a specific vibration source when the dynamic characteristics of the machine tool and the cutting process overlap and meet predetermined conditions. Occur. Among self-excited chatter vibrations, regenerative self-excited chatter vibration is caused by variations in chip thickness.
  • Patent Document 1 Conventionally, there is known a technique for suppressing regenerative self-excited chatter vibration by periodically varying the rotational speed of a spindle in a machine tool (see Patent Document 1, for example).
  • the machine tool control device may apply a predetermined speed clamp command to perform machining.
  • the machine tool keeps the speed of the spindle constant in the speed fluctuation range exceeding the clamp upper limit value of the speed clamp command, and chatter vibration cannot be suppressed. Therefore, there is a demand for a machine tool controller that can maintain a speed clamp command without impairing the chatter vibration suppression effect.
  • a control device for a machine tool is a variation command for generating a speed variation command based on a variation condition for periodically varying a speed command for a spindle motor in a machine tool and a rotational speed of the spindle motor.
  • a calculation unit is provided, and the fluctuation command calculation unit changes the phase of the speed fluctuation command or the speed command of the speed fluctuation command according to the speed clamp command of the spindle motor.
  • the speed clamp command can be maintained without impairing the chatter vibration suppression effect.
  • FIG. 4 is a diagram showing the relationship between a speed clamp command, a speed fluctuation command, and a spindle speed command according to the first embodiment; Indicates the speed fluctuation command before change. Shows the changed speed fluctuation command.
  • FIG. 10 is a diagram showing the relationship between a speed clamp command, a speed fluctuation command, and a spindle speed command according to the second embodiment; Indicates the spindle speed command before change. Shows the spindle speed command after change.
  • FIG. 9 is a flowchart showing processing of the motor control device according to the second embodiment;
  • FIG. 2 shows a conventional speed fluctuation command and a speed clamp command;
  • FIG. Shows the conventional speed change rate.
  • 4 shows a speed fluctuation command and a speed clamp command according to the first embodiment;
  • FIG. 11 shows a speed change rate according to the second embodiment;
  • FIG. 11 shows a speed fluctuation command and a speed clamp command according to the second embodiment;
  • FIG. FIG. 11 shows a speed change rate according to the second embodiment;
  • FIG. 11 shows a speed change rate according to the second embodiment;
  • FIG. 1 is a diagram showing an outline of a machine tool 1 according to this embodiment.
  • the machine tool 1 is a device that performs predetermined machining such as cutting by controlling the motor control device 10 and rotating the spindle motor 18 based on the speed command from the numerical control device 2 .
  • the machine tool 1 suppresses regenerative self-excited chatter vibration by periodically varying the rotation speed of the spindle motor 18, for example, by causing the rotation speed of the spindle motor 18 to oscillate sinusoidally.
  • the motor control device 10 includes a variation command calculation unit 11, a speed control unit 12, a current control unit 13, and a current detection unit 14.
  • the fluctuation command calculation unit 11 generates a speed fluctuation command based on fluctuation conditions for periodically fluctuating the speed command of the spindle motor 3 and the rotation speed of the spindle motor 18 in the machine tool. Specifically, the fluctuation command calculator 11 multiplies the rotation speed of the spindle motor 3 based on the speed command by a fluctuation amplitude rate (hereinafter simply referred to as an amplitude rate), which is a fluctuation condition, and periodically fluctuates. The amplitude of the rotation speed of the spindle motor 3 is calculated.
  • a fluctuation amplitude rate hereinafter simply referred to as an amplitude rate
  • the fluctuation command calculation unit 11 multiplies the rotation speed of the spindle motor 3 based on the speed command by a fluctuation frequency rate (hereinafter simply referred to as frequency rate), which is a fluctuation condition, to calculate the periodically fluctuating spindle motor 3.
  • a speed fluctuation command is generated by calculating the frequency of the rotation speed of .
  • the fluctuation command calculator 11 acquires a spindle speed command 21 and a speed clamp command 22 from the numerical controller 2 . Then, the fluctuation command calculator 11 changes the phase of the speed fluctuation command or the speed command of the speed fluctuation command according to the speed clamp command of the spindle motor 18 . As a result, the motor control device 10 can maintain the speed clamp command without impairing the chatter vibration suppression effect.
  • the fluctuation command calculator 11 changes (offsets) the phase of the speed fluctuation command so that the value of the speed clamp command 22 is not exceeded. to control.
  • the fluctuation command calculation unit 11 changes the spindle speed command of the speed fluctuation command so that the value of the speed clamp command 22 is not exceeded. to control.
  • the speed control unit 12 generates a command for controlling the rotation speed of the spindle motor 18 based on the spindle speed command and the speed fluctuation command, and outputs it as a signal.
  • a value obtained by subtracting the actual current feedback value output as a signal from the current detection unit 14 from the command value output from the speed control unit 12 is input to the current control unit 13 as a signal.
  • the current control unit 13 Based on the input signal, the current control unit 13 generates a voltage command for driving the spindle motor 18 and outputs it as a signal.
  • the current detection unit 14 detects a signal that is the current value of the spindle motor 18, and outputs the detection result as an actual current feedback signal.
  • the numerical controller 2 outputs a spindle speed command 21 and a speed clamp command 22 to the motor controller 10 .
  • a spindle speed command 21 includes a speed command for the spindle motor 18 and is output as a signal.
  • the speed clamp command 22 includes the upper limit of spindle speed that can be freely changed by the user according to the machining conditions of the machine tool 1 .
  • the speed clamp command 22 is generated according to the machining conditions of the machine tool 1 and output as a signal.
  • the spindle motor 18 rotates under the control of the motor control device 10 .
  • the speed detection unit 19 detects the rotation speed of the spindle motor 18 and outputs the detection result as a signal of actual speed feedback.
  • the speed detector 19 may be, for example, an encoder or the like.
  • FIG. 2 is a diagram showing the relationship between the speed clamp command SL (t), the speed fluctuation command SV (t), and the spindle speed command SN (t) according to the first embodiment.
  • the fluctuation command calculator 11 changes (offsets) the phase of the speed fluctuation command S V (t) when the speed fluctuation command S V (t) is equal to or greater than the speed clamp command S L (t). do.
  • the triangular wave formed by the dashed line indicates the speed fluctuation command S V (t) before change
  • the triangular wave formed by the solid line indicates the speed fluctuation after change.
  • a command S V (t) is shown.
  • the dashed line indicates the phase of the speed fluctuation command S V (t) before change (before offset), and the solid line indicates the phase after change (offset ) shows the phase of the speed variation command S V (t).
  • the speed fluctuation command S V (t) before change has a portion exceeding the speed clamp command S L (t).
  • the changed speed fluctuation command S V (t) is controlled so as not to exceed the speed clamp command S L (t) by offsetting the phase of the speed fluctuation command S V (t).
  • FIG. 3A shows the speed fluctuation command S V (t) before change
  • FIG. 3B shows the speed change command S V (t) after change.
  • the speed fluctuation command S V (t) before change has a portion exceeding the speed clamp command S L (t). Therefore, the spindle motor 18 has a portion where the speed becomes constant, and the motor control device 10 cannot suppress chatter vibration.
  • the changed speed fluctuation command S V (t) does not have a portion exceeding the speed clamp command S L (t). Therefore, the spindle motor 18 can avoid constant speed, and the motor control device 10 can maintain the speed clamp command without impairing the chatter vibration suppressing effect.
  • FIG. 4 is a flowchart showing processing of the motor control device 10 according to the first embodiment.
  • the fluctuation command calculator 11 acquires the current spindle speed command S N (t) [min-1] and speed clamp command S L (t) [min-1] from the numerical controller 2 .
  • t indicates the control period [s].
  • the fluctuation command calculator 11 acquires fluctuation conditions from a storage unit (not shown) of the motor control device 10 .
  • step S2 the fluctuation command calculator 11 calculates the amplitude A(t) [min-1] of the speed fluctuation command S V ( t), the frequency F Calculate (t) [Hz] and phase ⁇ (t) [rad].
  • amplitude A(t), frequency F(t) and phase ⁇ (t) are calculated using the following equations.
  • A(t) SN (t) ⁇ (a/100)
  • F(t) ( SN (t)/60) ⁇ (f/100)
  • ⁇ (t) mod( ⁇ (t ⁇ 1)+(2 ⁇ F(t) ⁇ t) ⁇ , 2 ⁇ )
  • Amplitude rate a (%) and frequency rate f (%) are fluctuation conditions, and mod is a remainder function. The remainder function mod rounds ⁇ (t) by 2 ⁇ .
  • step S3 the fluctuation command calculator 11 calculates a speed fluctuation command S V (t) [min-1].
  • the speed variation command S V (t) is calculated using the following formula.
  • SV (t) SN (t)+A(t)*tri ⁇ (t)
  • the fluctuation command calculator 11 may use a function that generates a sine wave instead of tri ⁇ (t) that is a function that generates a triangular wave.
  • the fluctuation command calculator 11 can calculate the speed fluctuation command S V (t) by replacing tri ⁇ (t) with sin ⁇ (t).
  • step S4 the fluctuation command calculator 11 determines whether or not the speed fluctuation command S V (t) exceeds the value of the speed clamp command S L (t). If the speed fluctuation command S V (t) exceeds the value of the speed clamp command S L (t) (YES), the process proceeds to step S5. On the other hand, if the speed fluctuation command S V (t) is less than or equal to the speed clamp command S L (t) (NO), then the process ends.
  • the fluctuation command calculator 11 calculates the speed fluctuation command S V (t) when the speed fluctuation command S V (t) exceeds the speed clamp command S L ( t ). t) change the phase. As a result, the fluctuation command calculator 11 offsets the phase of the speed fluctuation command S V (t) to control the speed clamp command S L (t) so that it does not exceed the speed clamp command S L (t). Therefore, the motor control device 10 according to the first embodiment can maintain the speed clamp command without impairing the chatter vibration suppressing effect.
  • FIG. 5 is a diagram showing the relationship between the speed clamp command SL (t), the speed fluctuation command SV (t), and the spindle speed command SN (t) according to the second embodiment.
  • the fluctuation command calculator 11 changes (offsets) the spindle speed command of the speed fluctuation command when the maximum amplitude value of the speed fluctuation command exceeds the speed clamp command.
  • the dashed triangular wave indicates the spindle speed command S N (t) before change
  • the solid triangular wave indicates the spindle speed after change.
  • a command S N (t) is shown.
  • the spindle speed command S N (t) before change is a reference speed command, and may be, for example, an average spindle speed.
  • FIG. 6A shows the spindle speed command SN (t) before change
  • FIG. 6B shows the spindle speed command SN (t)+A(t) after change.
  • the spindle speed command S N (t) before the change has a portion exceeding the speed clamp command S L (t). Therefore, the spindle motor 18 has a portion where the speed becomes constant, and chatter vibration cannot be suppressed.
  • the motor control device 10 can avoid the speed of the spindle motor 18 from becoming constant, and can maintain the speed clamp command without impairing the chatter vibration suppressing effect.
  • FIG. 7 is a flowchart showing processing of the motor control device 10 according to the second embodiment.
  • the fluctuation command calculator 11 acquires the current spindle speed command S N (t) [min-1] and speed clamp command S L (t) [min-1] from the numerical controller 2 .
  • t indicates the control period [s].
  • the fluctuation command calculator 11 acquires fluctuation conditions from a storage unit (not shown) of the motor control device 10 .
  • step S12 the fluctuation command calculator 11 calculates the amplitude A(t) [min-1], the frequency F Calculate (t) [Hz] and phase ⁇ (t) [rad].
  • amplitude A(t), frequency F(t) and phase ⁇ (t) are calculated using the same formulas as in the first embodiment.
  • step S13 the fluctuation command calculator 11 determines whether or not the maximum amplitude value S N (t)+A(t) of the speed fluctuation command S V (t) exceeds the speed clamp command S L (t). . If the maximum amplitude value SN (t)+A(t) exceeds the speed clamp command SL (t) (YES), the process proceeds to step S14. On the other hand, if the maximum amplitude value SN (t)+A(t) is equal to or less than the speed clamp command SL (t) (NO), the process proceeds to step S15.
  • step S14 the fluctuation command calculator 11 changes the spindle speed command SN (t) by offsetting the spindle speed command SN (t) by the maximum value of the fluctuation amplitude. That is, the fluctuation command calculator 11 changes the spindle speed command SN (t) using the following equation.
  • S N (t) S L (t) ⁇ A(t)
  • step S15 the fluctuation command calculator 11 calculates the speed fluctuation command S V (t) [min-1].
  • the speed variation command SV (t) is calculated using the same formula as in the first embodiment.
  • the calculated speed fluctuation command S V (t) is controlled so as not to exceed the speed clamp command S L (t).
  • the fluctuation command calculation unit 11 when the maximum amplitude value of the speed fluctuation command S V (t) exceeds the speed clamp command S L (t), Change the spindle speed command S N (t) of the variation command S V (t).
  • the fluctuation command calculator 11 offsets the spindle speed command S N (t) before change by the maximum value of the fluctuation amplitude, thereby controlling the speed clamp command S L (t) not to be exceeded. Therefore, the motor control device 10 according to the second embodiment can maintain the speed clamp command without impairing the chatter vibration suppressing effect.
  • FIGS. 8A to 8F are diagrams showing the chattering suppression effect and machining efficiency of the motor control device 10 according to the embodiment described above.
  • FIG. 8A shows a conventional speed fluctuation command and a speed clamp command
  • FIG. 8C shows a speed fluctuation command and a speed clamp command according to the first embodiment
  • FIG. 8B shows the conventional speed change rate
  • FIG. 8D shows the speed change rate according to the first embodiment
  • FIG. 8F shows the speed change rate according to the second embodiment.
  • the speed change rate is the ratio of the difference between the current speed and the speed one rotation before at the same main shaft rotation angle.
  • the spindle speed command S N (t) is 900 rpm
  • the speed clamp command S L (t) is 900 rpm
  • frequency F(t) 10%.
  • the average speed change rate (absolute value) per fluctuation cycle is about 6.2%. From the results of FIGS. 8C and 8D, in the method of the first embodiment, the average speed change rate (absolute value) per fluctuation cycle is about 11%. From the results of FIGS. 8E and 8F, in the method of the second embodiment, the average speed change rate (absolute value) per fluctuation cycle is approximately 19%. Therefore, it can be seen that the rate of change in speed (that is, chatter suppression effect) increases in the order of the conventional system, the system of the first embodiment, and the system of the second embodiment.
  • the average spindle speed per fluctuation cycle is about 832 rpm.
  • the average spindle speed per fluctuation cycle is approximately 765 rpm.
  • the average spindle speed per fluctuation cycle is approximately 630 rpm. Therefore, the machining efficiency (that is, the average spindle speed) is higher in the order of the system of the second embodiment, the system of the first embodiment, and the conventional system.
  • the conventional method is less effective in suppressing chatter vibration, there is a high possibility that machining will not be possible.
  • the motor control device 10 can be realized by hardware, software, or a combination thereof. Also, the control method performed by the motor control device 10 described above can be implemented by hardware, software, or a combination thereof.
  • “implemented by software” means implemented by a computer reading and executing a program.
  • Non-transitory computer-readable media include various types of tangible storage media.
  • Examples of non-transitory computer-readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical discs), CD-ROMs (Read Only Memory), CD-Rs, CD-R/ W, semiconductor memory (eg, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)).

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Abstract

Provided is a control device of a machine tool that can maintain a speed clamp command, without impairing a chatter vibration suppression effect. A control device of a machine tool comprises a fluctuation command calculation unit that generates a speed fluctuation command on the basis of a speed command for a spindle motor in the machine tool and a fluctuation condition for periodically fluctuating a rotation speed of the spindle motor. The fluctuation command calculation unit changes a phase of the speed fluctuation command or a speed command of the speed fluctuation command, in accordance with a speed clamp command for the spindle motor.

Description

工作機械の制御装置machine tool controller
　本発明は、工作機械の制御装置に関する。 The present invention relates to a control device for machine tools.
　工作機械による切削加工時には、工具とワークとの間で継続的にびびり振動が発生することがある。びびり振動は、振動発生の要因から、強制びびり振動と自励びびり振動とに分類される。強制びびり振動は、強制的な振動源の影響を受けて発生し、自励びびり振動は、工作機械の動特性と切削過程とが重なって所定の条件を満たしたときに特定の振動源なしに発生する。自励びびり振動のうち、再生型の自励びびり振動は、切り屑厚さの変動によって生じる。 　When cutting with a machine tool, chatter vibration may occur continuously between the tool and the workpiece. Chatter vibration is classified into forced chatter vibration and self-excited chatter vibration according to the factors of vibration generation. Forced chatter vibration is generated under the influence of a forced vibration source, and self-excited chatter vibration is generated without a specific vibration source when the dynamic characteristics of the machine tool and the cutting process overlap and meet predetermined conditions. Occur. Among self-excited chatter vibrations, regenerative self-excited chatter vibration is caused by variations in chip thickness.
　従来、再生型の自励びびり振動を、工作機械における主軸の回転速度を周期的に変動させることで抑制する技術が知られている（例えば、特許文献１参照）。 Conventionally, there is known a technique for suppressing regenerative self-excited chatter vibration by periodically varying the rotational speed of a spindle in a machine tool (see Patent Document 1, for example).
特開２０１３－６３４９７号公報JP 2013-63497 A
　このようなびびり振動を抑制する技術において、工作機械の制御装置は、所定の速度クランプ指令を適用し、加工を行う場合がある。この場合、工作機械は、速度クランプ指令のクランプ上限値を超える速度変動域において、主軸の速度が一定速度となり、びびり振動を抑制することができない。そこで、びびり振動抑制効果を損なうことなく、速度クランプ指令を維持することができる工作機械の制御装置が求められている。 In the technique of suppressing chatter vibration, the machine tool control device may apply a predetermined speed clamp command to perform machining. In this case, the machine tool keeps the speed of the spindle constant in the speed fluctuation range exceeding the clamp upper limit value of the speed clamp command, and chatter vibration cannot be suppressed. Therefore, there is a demand for a machine tool controller that can maintain a speed clamp command without impairing the chatter vibration suppression effect.
　本開示の一態様に係る工作機械の制御装置は、工作機械における主軸モータの速度指令及び前記主軸モータの回転速度を周期的に変動させるための変動条件に基づいて速度変動指令を生成する変動指令計算部を備え、前記変動指令計算部は、前記主軸モータの速度クランプ指令に応じて、前記速度変動指令の位相又は前記速度変動指令の速度指令を変更する。 A control device for a machine tool according to an aspect of the present disclosure is a variation command for generating a speed variation command based on a variation condition for periodically varying a speed command for a spindle motor in a machine tool and a rotational speed of the spindle motor. A calculation unit is provided, and the fluctuation command calculation unit changes the phase of the speed fluctuation command or the speed command of the speed fluctuation command according to the speed clamp command of the spindle motor.
　本発明によれば、びびり振動抑制効果を損なうことなく、速度クランプ指令を維持することができる。 According to the present invention, the speed clamp command can be maintained without impairing the chatter vibration suppression effect.
本実施形態に係る工作機械の概要を示す図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the outline|summary of the machine tool which concerns on this embodiment. 第１実施形態に係る速度クランプ指令、速度変動指令及び主軸速度指令の関係を示す図である。FIG. 4 is a diagram showing the relationship between a speed clamp command, a speed fluctuation command, and a spindle speed command according to the first embodiment; 変更前の速度変動指令を示す。Indicates the speed fluctuation command before change. 変更後の速度変動指令を示す。Shows the changed speed fluctuation command. 第１実施形態に係るモータ制御装置の処理を示すフローチャートである。4 is a flowchart showing processing of the motor control device according to the first embodiment; 第２実施形態に係る速度クランプ指令、速度変動指令及び主軸速度指令の関係を示す図である。FIG. 10 is a diagram showing the relationship between a speed clamp command, a speed fluctuation command, and a spindle speed command according to the second embodiment; 変更前の主軸速度指令を示す。Indicates the spindle speed command before change. 変更後の主軸速度指令を示す。Shows the spindle speed command after change. 第２実施形態に係るモータ制御装置の処理を示すフローチャートである。9 is a flowchart showing processing of the motor control device according to the second embodiment; 従来の速度変動指令及び速度クランプ指令を示す。FIG. 2 shows a conventional speed fluctuation command and a speed clamp command; FIG. 従来の速度変化率を示す。Shows the conventional speed change rate. 第１実施形態に係る速度変動指令及び速度クランプ指令を示す。4 shows a speed fluctuation command and a speed clamp command according to the first embodiment; 第２実施形態に係る速度変化率を示す。FIG. 11 shows a speed change rate according to the second embodiment; FIG. 第２実施形態に係る速度変動指令及び速度クランプ指令を示す。FIG. 11 shows a speed fluctuation command and a speed clamp command according to the second embodiment; FIG. 第２実施形態に係る速度変化率を示す。FIG. 11 shows a speed change rate according to the second embodiment; FIG.
　以下、本発明の実施形態の一例について説明する。図１は、本実施形態に係る工作機械１の概要を示す図である。 An example of an embodiment of the present invention will be described below. FIG. 1 is a diagram showing an outline of a machine tool 1 according to this embodiment.
　工作機械１は、数値制御装置２からの速度指令に基づき、モータ制御装置１０を制御して、主軸モータ１８を回転させることで、切削加工等の所定の加工を行う装置である。工作機械１は、主軸モータ１８の回転速度を周期的に変動させることで、例えば、主軸モータ１８の回転速度を正弦波振動させることで、再生型の自励びびり振動を抑制する。 The machine tool 1 is a device that performs predetermined machining such as cutting by controlling the motor control device 10 and rotating the spindle motor 18 based on the speed command from the numerical control device 2 . The machine tool 1 suppresses regenerative self-excited chatter vibration by periodically varying the rotation speed of the spindle motor 18, for example, by causing the rotation speed of the spindle motor 18 to oscillate sinusoidally.
　モータ制御装置１０は、変動指令計算部１１と、速度制御部１２と、電流制御部１３と、電流検出部１４と、を備える。 The motor control device 10 includes a variation command calculation unit 11, a speed control unit 12, a current control unit 13, and a current detection unit 14.
　変動指令計算部１１は、工作機械における主軸モータ３の速度指令及び主軸モータ１８の回転速度を周期的に変動させるための変動条件に基づいて速度変動指令を生成する。具体的には、変動指令計算部１１は、速度指令に基づく主軸モータ３の回転速度に、変動条件である変動振幅率（以下、単に振幅率ともいう。）を乗じて、周期的に変動する主軸モータ３の回転速度の振幅を計算する。更に、変動指令計算部１１は、速度指令に基づく主軸モータ３の回転速度に、変動条件である変動周波数率（以下、単に周波数率ともいう。）を乗じて、周期的に変動する主軸モータ３の回転速度の周波数を計算することで、速度変動指令を生成する。 The fluctuation command calculation unit 11 generates a speed fluctuation command based on fluctuation conditions for periodically fluctuating the speed command of the spindle motor 3 and the rotation speed of the spindle motor 18 in the machine tool. Specifically, the fluctuation command calculator 11 multiplies the rotation speed of the spindle motor 3 based on the speed command by a fluctuation amplitude rate (hereinafter simply referred to as an amplitude rate), which is a fluctuation condition, and periodically fluctuates. The amplitude of the rotation speed of the spindle motor 3 is calculated. Furthermore, the fluctuation command calculation unit 11 multiplies the rotation speed of the spindle motor 3 based on the speed command by a fluctuation frequency rate (hereinafter simply referred to as frequency rate), which is a fluctuation condition, to calculate the periodically fluctuating spindle motor 3. A speed fluctuation command is generated by calculating the frequency of the rotation speed of .
　更に、変動指令計算部１１は、数値制御装置２から主軸速度指令２１及び速度クランプ指令２２を取得する。そして、変動指令計算部１１は、主軸モータ１８の速度クランプ指令に応じて、速度変動指令の位相又は速度変動指令の速度指令を変更する。これにより、モータ制御装置１０は、びびり振動抑制効果を損なうことなく、速度クランプ指令を維持することができる。 Further, the fluctuation command calculator 11 acquires a spindle speed command 21 and a speed clamp command 22 from the numerical controller 2 . Then, the fluctuation command calculator 11 changes the phase of the speed fluctuation command or the speed command of the speed fluctuation command according to the speed clamp command of the spindle motor 18 . As a result, the motor control device 10 can maintain the speed clamp command without impairing the chatter vibration suppression effect.
　具体的には、変動指令計算部１１は、速度変動指令が、速度クランプ指令２２の値を超える場合、速度変動指令の位相を変更（オフセット）することによって、速度クランプ指令２２の値を超えないように制御する。 Specifically, when the speed fluctuation command exceeds the value of the speed clamp command 22, the fluctuation command calculator 11 changes (offsets) the phase of the speed fluctuation command so that the value of the speed clamp command 22 is not exceeded. to control.
　また、変動指令計算部１１は、速度変動指令の最大振幅値が、速度クランプ指令２２の値を超える場合、速度変動指令の主軸速度指令を変更することによって、速度クランプ指令２２の値を超えないように制御する。 Further, when the maximum amplitude value of the speed fluctuation command exceeds the value of the speed clamp command 22, the fluctuation command calculation unit 11 changes the spindle speed command of the speed fluctuation command so that the value of the speed clamp command 22 is not exceeded. to control.
　速度制御部１２は、主軸速度指令及び速度変動指令に基づいて主軸モータ１８の回転速度を制御する指令を生成し、信号として出力する。 The speed control unit 12 generates a command for controlling the rotation speed of the spindle motor 18 based on the spindle speed command and the speed fluctuation command, and outputs it as a signal.
　速度制御部１２から出力される指令の値から、電流検出部１４から信号として出力される実電流フィードバックの値を減算して得られた値は、信号として電流制御部１３に入力される。 A value obtained by subtracting the actual current feedback value output as a signal from the current detection unit 14 from the command value output from the speed control unit 12 is input to the current control unit 13 as a signal.
　電流制御部１３は、入力された信号に基づいて、主軸モータ１８を駆動するための電圧指令を生成し、信号として出力する。 Based on the input signal, the current control unit 13 generates a voltage command for driving the spindle motor 18 and outputs it as a signal.
　電流検出部１４は、主軸モータ１８の電流値である信号を検出し、検出結果を実電流フィードバックの信号として出力する。 The current detection unit 14 detects a signal that is the current value of the spindle motor 18, and outputs the detection result as an actual current feedback signal.
　数値制御装置２は、主軸速度指令２１及び速度クランプ指令２２をモータ制御装置１０へ出力する。主軸速度指令２１は、主軸モータ１８の速度指令を含み、信号として出力される。速度クランプ指令２２は、工作機械１の加工条件に応じてユーザが自由に変更可能な主軸速度の上限を含む。速度クランプ指令２２は、工作機械１の加工条件に応じて生成され、信号として出力される。 The numerical controller 2 outputs a spindle speed command 21 and a speed clamp command 22 to the motor controller 10 . A spindle speed command 21 includes a speed command for the spindle motor 18 and is output as a signal. The speed clamp command 22 includes the upper limit of spindle speed that can be freely changed by the user according to the machining conditions of the machine tool 1 . The speed clamp command 22 is generated according to the machining conditions of the machine tool 1 and output as a signal.
　主軸モータ１８は、モータ制御装置１０の制御下において回転する。速度検出部１９は、主軸モータ１８の回転速度を検出し、検出結果を実速度フィードバックの信号として出力する。速度検出部１９は、例えば、エンコーダ等であってもよい。 The spindle motor 18 rotates under the control of the motor control device 10 . The speed detection unit 19 detects the rotation speed of the spindle motor 18 and outputs the detection result as a signal of actual speed feedback. The speed detector 19 may be, for example, an encoder or the like.
＜第１実施形態＞
　図２は、第１実施形態に係る速度クランプ指令ＳＬ（ｔ）、速度変動指令ＳＶ（ｔ）及び主軸速度指令ＳＮ（ｔ）の関係を示す図である。上述したように、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）が、速度クランプ指令ＳＬ（ｔ）以上である場合、速度変動指令ＳＶ（ｔ）の位相を変更（オフセット）する。 <First Embodiment>
FIG. 2 is a diagram showing the relationship between the speed clamp command SL (t), the speed fluctuation command SV (t), and the spindle speed command SN (t) according to the first embodiment. As described above, the fluctuation command calculator 11 changes (offsets) the phase of the speed fluctuation command S V (t) when the speed fluctuation command S V (t) is equal to or greater than the speed clamp command S L (t). do.
　図２の時間ｔと速度との関係を示すグラフにおいて、破線で構成される三角波は、変更前の速度変動指令ＳＶ（ｔ）を示し、実線で構成される三角波は、変更後の速度変動指令ＳＶ（ｔ）を示す。 In the graph showing the relationship between time t and speed in FIG. 2, the triangular wave formed by the dashed line indicates the speed fluctuation command S V (t) before change, and the triangular wave formed by the solid line indicates the speed fluctuation after change. A command S V (t) is shown.
　また、図２の時間ｔと位相Θとの関係を示すグラフにおいて、破線部分は、変更前（オフセット前）の速度変動指令ＳＶ（ｔ）の位相を示し、実線部分は、変更後（オフセット後）の速度変動指令ＳＶ（ｔ）の位相を示す。 In the graph showing the relationship between time t and phase Θ in FIG. 2, the dashed line indicates the phase of the speed fluctuation command S V (t) before change (before offset), and the solid line indicates the phase after change (offset ) shows the phase of the speed variation command S V (t).
　図２における三角波に示されるように、変更前の速度変動指令ＳＶ（ｔ）は、速度クランプ指令ＳＬ（ｔ）を超えている部分が存在する。一方、変更後の速度変動指令ＳＶ（ｔ）は、速度変動指令ＳＶ（ｔ）の位相をオフセットすることによって、速度クランプ指令ＳＬ（ｔ）を超えないように制御される。 As shown by the triangular wave in FIG. 2, the speed fluctuation command S V (t) before change has a portion exceeding the speed clamp command S L (t). On the other hand, the changed speed fluctuation command S V (t) is controlled so as not to exceed the speed clamp command S L (t) by offsetting the phase of the speed fluctuation command S V (t).
　図３Ａは、変更前の速度変動指令ＳＶ（ｔ）を示し、図３Ｂは、変更後の速度変動指令ＳＶ（ｔ）を示す。図３Ａに示すように、変更前の速度変動指令ＳＶ（ｔ）は、速度クランプ指令ＳＬ（ｔ）を超えている部分が存在する。そのため、主軸モータ１８は、速度が一定になる部分が発生し、モータ制御装置１０は、びびり振動を抑制することができない。 FIG. 3A shows the speed fluctuation command S V (t) before change, and FIG. 3B shows the speed change command S V (t) after change. As shown in FIG. 3A, the speed fluctuation command S V (t) before change has a portion exceeding the speed clamp command S L (t). Therefore, the spindle motor 18 has a portion where the speed becomes constant, and the motor control device 10 cannot suppress chatter vibration.
　一方、図３Ｂに示すように、変更後の速度変動指令ＳＶ（ｔ）は、速度クランプ指令ＳＬ（ｔ）を超えている部分が存在しない。そのため、主軸モータ１８は、速度が一定となることを回避でき、モータ制御装置１０は、びびり振動抑制効果を損なうことなく、速度クランプ指令を維持することができる。 On the other hand, as shown in FIG. 3B, the changed speed fluctuation command S V (t) does not have a portion exceeding the speed clamp command S L (t). Therefore, the spindle motor 18 can avoid constant speed, and the motor control device 10 can maintain the speed clamp command without impairing the chatter vibration suppressing effect.
　図４は、第１実施形態に係るモータ制御装置１０の処理を示すフローチャートである。
　ステップＳ１において、変動指令計算部１１は、現在の主軸速度指令ＳＮ（ｔ）［ｍｉｎ－１］及び速度クランプ指令ＳＬ（ｔ）［ｍｉｎ－１］を数値制御装置２から取得する。ここで、ｔは、制御周期［ｓ］を示す。また、変動指令計算部１１は、モータ制御装置１０の記憶部（図示せず）から変動条件を取得する。 FIG. 4 is a flowchart showing processing of the motor control device 10 according to the first embodiment.
In step S1, the fluctuation command calculator 11 acquires the current spindle speed command S N (t) [min-1] and speed clamp command S L (t) [min-1] from the numerical controller 2 . Here, t indicates the control period [s]. In addition, the fluctuation command calculator 11 acquires fluctuation conditions from a storage unit (not shown) of the motor control device 10 .
　ステップＳ２において、変動指令計算部１１は、現在の主軸速度指令ＳＮ（ｔ）及び変動条件に基づいて、速度変動指令ＳＶ（ｔ）の振幅Ａ（ｔ）［ｍｉｎ－１］、周波数Ｆ（ｔ）［Ｈｚ］及び位相Θ（ｔ）［ｒａｄ］を計算する。
　ここで、振幅Ａ（ｔ）、周波数Ｆ（ｔ）及び位相Θ（ｔ）は、以下の式を用いて計算される。
　Ａ（ｔ）＝ＳＮ（ｔ）×（ａ／１００）
　Ｆ（ｔ）＝（ＳＮ（ｔ）／６０）×（ｆ／１００）
　Θ（ｔ）＝ｍｏｄ（｛Θ（ｔ－１）＋（２π×Ｆ（ｔ）×ｔ）｝,２π）
　なお、振幅率ａ（％）及び周波数率ｆ（％）は、変動条件であり、ｍｏｄは、剰余関数である。剰余関数ｍｏｄは、Θ（ｔ）を２πにより丸めている。 In step S2, the fluctuation command calculator 11 calculates the amplitude A(t) [min-1] of the speed fluctuation command S V ( t), the frequency F Calculate (t) [Hz] and phase Θ(t) [rad].
Here, amplitude A(t), frequency F(t) and phase Θ(t) are calculated using the following equations.
A(t)= SN (t)×(a/100)
F(t)=( SN (t)/60)×(f/100)
Θ(t)=mod({Θ(t−1)+(2π×F(t)×t)}, 2π)
Amplitude rate a (%) and frequency rate f (%) are fluctuation conditions, and mod is a remainder function. The remainder function mod rounds Θ(t) by 2π.
　ステップＳ３において、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）［ｍｉｎ－１］を計算する。
　ここで、速度変動指令ＳＶ（ｔ）は、以下の式を用いて計算される。
　ＳＶ（ｔ）＝ＳＮ（ｔ）＋Ａ（ｔ）＊ｔｒｉΘ（ｔ）
　なお、ｔｒｉΘ（ｔ）は、三角波を生成する関数であり、例えば、以下のように生成される。
Ｉｆ　（Θ（ｔ）≦（π／２））
　　｛ｔｒｉΘ（ｔ）＝Θ（ｔ）／（π／２）｝
　Ｅｌｓｅ　ｉｆ　（Θ（ｔ）　≦　（３／２π））
　　　｛ｔｒｉΘ（ｔ）＝２－（Θ（ｔ）／（π／２））｝
　Ｅｌｓｅ　
　　　　｛ｔｒｉΘ（ｔ）＝（２Θ（ｔ）／π）－４｝ In step S3, the fluctuation command calculator 11 calculates a speed fluctuation command S V (t) [min-1].
Here, the speed variation command S V (t) is calculated using the following formula.
SV (t)= SN (t)+A(t)*triΘ(t)
Note that triΘ(t) is a function that generates a triangular wave, and is generated as follows, for example.
If (Θ(t)≤(π/2))
{triΘ(t)=Θ(t)/(π/2)}
Else if (Θ(t) ≤ (3/2π))
{triΘ(t)=2−(Θ(t)/(π/2))}
Else
{triΘ(t)=(2Θ(t)/π)−4}
　また、変動指令計算部１１は、三角波を生成する関数であるｔｒｉΘ（ｔ）に代えて、正弦波を生成する関数を用いてもよい。正弦波を生成する関数を用いる場合、変動指令計算部１１は、ｔｒｉΘ（ｔ）をｓｉｎΘ（ｔ）に置き換えることによって、速度変動指令ＳＶ（ｔ）を計算することができる。 Further, the fluctuation command calculator 11 may use a function that generates a sine wave instead of triΘ(t) that is a function that generates a triangular wave. When using a function that generates a sine wave, the fluctuation command calculator 11 can calculate the speed fluctuation command S V (t) by replacing triΘ(t) with sinΘ(t).
　ステップＳ４において、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）が、速度クランプ指令ＳＬ（ｔ）の値を超えるか否かを判定する。速度変動指令ＳＶ（ｔ）が、速度クランプ指令ＳＬ（ｔ）の値を超える場合（ＹＥＳ）、処理は、ステップＳ５へ進む。一方、速度変動指令ＳＶ（ｔ）が、速度クランプ指令ＳＬ（ｔ）の値以下の場合（ＮＯ）、処理は、その後、終了する。 In step S4, the fluctuation command calculator 11 determines whether or not the speed fluctuation command S V (t) exceeds the value of the speed clamp command S L (t). If the speed fluctuation command S V (t) exceeds the value of the speed clamp command S L (t) (YES), the process proceeds to step S5. On the other hand, if the speed fluctuation command S V (t) is less than or equal to the speed clamp command S L (t) (NO), then the process ends.
　ステップＳ５において、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）の位相Θ（ｔ）をπ－Θ（ｔ）に変更し、速度変動指令ＳＶ（ｔ）を再計算する。
　すなわち、変動指令計算部１１は、以下の式を用いて速度変動指令ＳＶ（ｔ）を再計算する。
　Θ（ｔ）＝π－Θ（ｔ）
　ＳＶ（ｔ）＝ＳＮ（ｔ）＋Ａ（ｔ）＊ｔｒｉΘ（ｔ）
　これにより、再計算された速度変動指令ＳＶ（ｔ）は、位相Θ（ｔ）をオフセットすることによって、速度クランプ指令ＳＬ（ｔ）を超えないように制御される。 In step S5, the fluctuation command calculator 11 changes the phase Θ(t) of the speed fluctuation command S V (t) to π-Θ(t), and recalculates the speed fluctuation command S V (t).
That is, the fluctuation command calculator 11 recalculates the speed fluctuation command S V (t) using the following equation.
Θ(t) = π-Θ(t)
SV (t)= SN (t)+A(t)*triΘ(t)
Thereby, the recalculated speed fluctuation command S V (t) is controlled so as not to exceed the speed clamp command S L (t) by offsetting the phase Θ(t).
　このように第１実施形態に係るモータ制御装置１０において、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）が、速度クランプ指令ＳＬ（ｔ）を超える場合、速度変動指令ＳＶ（ｔ）の位相を変更する。これにより、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）の位相をオフセットすることによって、速度クランプ指令ＳＬ（ｔ）を超えないように制御する。したがって、第１実施形態に係るモータ制御装置１０は、びびり振動抑制効果を損なうことなく、速度クランプ指令を維持することができる。 As described above, in the motor control device 10 according to the first embodiment, the fluctuation command calculator 11 calculates the speed fluctuation command S V (t) when the speed fluctuation command S V (t) exceeds the speed clamp command S L ( t ). t) change the phase. As a result, the fluctuation command calculator 11 offsets the phase of the speed fluctuation command S V (t) to control the speed clamp command S L (t) so that it does not exceed the speed clamp command S L (t). Therefore, the motor control device 10 according to the first embodiment can maintain the speed clamp command without impairing the chatter vibration suppressing effect.
＜第２実施形態＞
　図５は、第２実施形態に係る速度クランプ指令ＳＬ（ｔ）、速度変動指令ＳＶ（ｔ）及び主軸速度指令ＳＮ（ｔ）の関係を示す図である。上述したように、変動指令計算部１１は、速度変動指令の最大振幅値が、速度クランプ指令を超える場合、速度変動指令の主軸速度指令を変更（オフセット）する。 <Second embodiment>
FIG. 5 is a diagram showing the relationship between the speed clamp command SL (t), the speed fluctuation command SV (t), and the spindle speed command SN (t) according to the second embodiment. As described above, the fluctuation command calculator 11 changes (offsets) the spindle speed command of the speed fluctuation command when the maximum amplitude value of the speed fluctuation command exceeds the speed clamp command.
　図５の時間ｔと速度との関係を示すグラフにおいて、破線で構成される三角波は、変更前の主軸速度指令ＳＮ（ｔ）を示し、実線で構成される三角波は、変更後の主軸速度指令ＳＮ（ｔ）を示す。 In the graph showing the relationship between time t and speed in FIG. 5, the dashed triangular wave indicates the spindle speed command S N (t) before change, and the solid triangular wave indicates the spindle speed after change. A command S N (t) is shown.
　図５における三角波に示されるように、変更前の主軸速度指令ＳＮ（ｔ）は、速度クランプ指令ＳＬ（ｔ）を超えている部分が存在する。一方、変更後の主軸速度指令ＳＮ（ｔ）は、変更前の主軸速度指令ＳＮ（ｔ）を変動振幅の最大値分だけオフセットすることによって、速度クランプ指令ＳＬ（ｔ）を超えないように制御される。なお、変更前の主軸速度指令ＳＮ（ｔ）は、基準となる速度指令であり、例えば、平均主軸速度であってもよい。 As shown by the triangular wave in FIG. 5, the spindle speed command SN (t) before change has a portion exceeding the speed clamp command SL (t). On the other hand, the spindle speed command S N (t) after change does not exceed the speed clamp command S L (t) by offsetting the spindle speed command S N (t) before change by the maximum value of the fluctuation amplitude. controlled as The spindle speed command S N (t) before change is a reference speed command, and may be, for example, an average spindle speed.
　図６Ａは、変更前の主軸速度指令ＳＮ（ｔ）を示し、図６Ｂは、変更後の主軸速度指令ＳＮ（ｔ）＋Ａ（ｔ）を示す。図６Ａに示すように、変更前の主軸速度指令ＳＮ（ｔ）は、速度クランプ指令ＳＬ（ｔ）を超えている部分が存在する。そのため、主軸モータ１８は、速度が一定になる部分が発生し、びびり振動を抑制することができない。 FIG. 6A shows the spindle speed command SN (t) before change, and FIG. 6B shows the spindle speed command SN (t)+A(t) after change. As shown in FIG. 6A, the spindle speed command S N (t) before the change has a portion exceeding the speed clamp command S L (t). Therefore, the spindle motor 18 has a portion where the speed becomes constant, and chatter vibration cannot be suppressed.
　一方、図６Ｂに示すように、変更後の主軸速度指令ＳＮ（ｔ）＋Ａ（ｔ）は、速度クランプ指令ＳＬ（ｔ）を超えている部分が存在しない。そのため、モータ制御装置１０は、主軸モータ１８の速度が一定となることを回避でき、びびり振動抑制効果を損なうことなく、速度クランプ指令を維持することができる。 On the other hand, as shown in FIG. 6B, the changed spindle speed command SN (t)+A(t) does not have a portion exceeding the speed clamp command SL (t). Therefore, the motor control device 10 can avoid the speed of the spindle motor 18 from becoming constant, and can maintain the speed clamp command without impairing the chatter vibration suppressing effect.
　図７は、第２実施形態に係るモータ制御装置１０の処理を示すフローチャートである。
　ステップＳ１１において、変動指令計算部１１は、現在の主軸速度指令ＳＮ（ｔ）［ｍｉｎ－１］及び速度クランプ指令ＳＬ（ｔ）［ｍｉｎ－１］を数値制御装置２から取得する。ここで、ｔは、制御周期［ｓ］を示す。また、変動指令計算部１１は、モータ制御装置１０の記憶部（図示せず）から変動条件を取得する。 FIG. 7 is a flowchart showing processing of the motor control device 10 according to the second embodiment.
In step S11, the fluctuation command calculator 11 acquires the current spindle speed command S N (t) [min-1] and speed clamp command S L (t) [min-1] from the numerical controller 2 . Here, t indicates the control period [s]. In addition, the fluctuation command calculator 11 acquires fluctuation conditions from a storage unit (not shown) of the motor control device 10 .
　ステップＳ１２において、変動指令計算部１１は、現在の主軸速度指令ＳＮ（ｔ）及び変動条件に基づいて、速度変動指令ＳＶ（ｔ）の振幅Ａ（ｔ）［ｍｉｎ－１］、周波数Ｆ（ｔ）［Ｈｚ］及び位相Θ（ｔ）［ｒａｄ］を計算する。
　ここで、振幅Ａ（ｔ）、周波数Ｆ（ｔ）及び位相Θ（ｔ）は、第１実施形態と同様の式を用いて計算される。 In step S12, the fluctuation command calculator 11 calculates the amplitude A(t) [min-1], the frequency F Calculate (t) [Hz] and phase Θ(t) [rad].
Here, amplitude A(t), frequency F(t) and phase Θ(t) are calculated using the same formulas as in the first embodiment.
　ステップＳ１３において、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）の最大振幅値ＳＮ（ｔ）＋Ａ（ｔ）が、速度クランプ指令ＳＬ（ｔ）を超えるか否かを判定する。最大振幅値ＳＮ（ｔ）＋Ａ（ｔ）が、速度クランプ指令ＳＬ（ｔ）を超える場合（ＹＥＳ）、処理は、ステップＳ１４へ進む。一方、最大振幅値ＳＮ（ｔ）＋Ａ（ｔ）が、速度クランプ指令ＳＬ（ｔ）以下の場合（ＮＯ）、処理は、ステップＳ１５へ進む。 In step S13, the fluctuation command calculator 11 determines whether or not the maximum amplitude value S N (t)+A(t) of the speed fluctuation command S V (t) exceeds the speed clamp command S L (t). . If the maximum amplitude value SN (t)+A(t) exceeds the speed clamp command SL (t) (YES), the process proceeds to step S14. On the other hand, if the maximum amplitude value SN (t)+A(t) is equal to or less than the speed clamp command SL (t) (NO), the process proceeds to step S15.
　ステップＳ１４において、変動指令計算部１１は、主軸速度指令ＳＮ（ｔ）を変動振幅の最大値分だけオフセットすることによって、主軸速度指令ＳＮ（ｔ）を変更する。すなわち、変動指令計算部１１は、以下の式を用いて主軸速度指令ＳＮ（ｔ）を変更する。
　ＳＮ（ｔ）＝ＳＬ（ｔ）－Ａ（ｔ） In step S14, the fluctuation command calculator 11 changes the spindle speed command SN (t) by offsetting the spindle speed command SN (t) by the maximum value of the fluctuation amplitude. That is, the fluctuation command calculator 11 changes the spindle speed command SN (t) using the following equation.
S N (t)=S L (t)−A(t)
　ステップＳ１５において、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）［ｍｉｎ－１］を計算する。ここで、速度変動指令ＳＶ（ｔ）は、第１実施形態と同様の式を用いて計算される。これにより、計算された速度変動指令ＳＶ（ｔ）は、速度クランプ指令ＳＬ（ｔ）を超えないように制御される。 In step S15, the fluctuation command calculator 11 calculates the speed fluctuation command S V (t) [min-1]. Here, the speed variation command SV (t) is calculated using the same formula as in the first embodiment. As a result, the calculated speed fluctuation command S V (t) is controlled so as not to exceed the speed clamp command S L (t).
　このように第２実施形態に係るモータ制御装置１０において、変動指令計算部１１は、速度変動指令ＳＶ（ｔ）の最大振幅値が、速度クランプ指令ＳＬ（ｔ）を超える場合、前記速度変動指令ＳＶ（ｔ）の主軸速度指令ＳＮ（ｔ）を変更する。これにより、変動指令計算部１１は、変更前の主軸速度指令ＳＮ（ｔ）を変動振幅の最大値分だけオフセットすることによって、速度クランプ指令ＳＬ（ｔ）を超えないように制御する。したがって、第２実施形態に係るモータ制御装置１０は、びびり振動抑制効果を損なうことなく、速度クランプ指令を維持することができる。 As described above, in the motor control device 10 according to the second embodiment, the fluctuation command calculation unit 11, when the maximum amplitude value of the speed fluctuation command S V (t) exceeds the speed clamp command S L (t), Change the spindle speed command S N (t) of the variation command S V (t). As a result, the fluctuation command calculator 11 offsets the spindle speed command S N (t) before change by the maximum value of the fluctuation amplitude, thereby controlling the speed clamp command S L (t) not to be exceeded. Therefore, the motor control device 10 according to the second embodiment can maintain the speed clamp command without impairing the chatter vibration suppressing effect.
　図８Ａ～図８Ｆは、上述した実施形態に係るモータ制御装置１０によるびびり抑制効果及び加工能率について示す図である。詳細には、図８Ａは、従来の速度変動指令及び速度クランプ指令を示し、図８Ｃは、第１実施形態に係る速度変動指令及び速度クランプ指令を示し、図８Ｅは、第２実施形態に係る速度変動指令及び速度クランプ指令を示す。また、図８Ｂは、従来の速度変化率を示し、図８Ｄは、第１実施形態に係る速度変化率を示し、図８Ｆは、第２実施形態に係る速度変化率を示す。なお、主軸モータ３の主軸回転角度が、０度から３６０度である場合、同一主軸回転角において、現在の速度と１回転前の速度差の比率を速度変化率とする。 FIGS. 8A to 8F are diagrams showing the chattering suppression effect and machining efficiency of the motor control device 10 according to the embodiment described above. Specifically, FIG. 8A shows a conventional speed fluctuation command and a speed clamp command, FIG. 8C shows a speed fluctuation command and a speed clamp command according to the first embodiment, and FIG. Indicates speed fluctuation command and speed clamp command. Also, FIG. 8B shows the conventional speed change rate, FIG. 8D shows the speed change rate according to the first embodiment, and FIG. 8F shows the speed change rate according to the second embodiment. When the main shaft rotation angle of the main shaft motor 3 is from 0 to 360 degrees, the speed change rate is the ratio of the difference between the current speed and the speed one rotation before at the same main shaft rotation angle.
　なお、図８Ａ～図８Ｆでは、主軸速度指令ＳＮ（ｔ）は、９００ｒｐｍであり、速度クランプ指令ＳＬ（ｔ）は、９００ｒｐｍであり、変更条件は、変動振幅Ａ（ｔ）＝３０％、周波数Ｆ（ｔ）＝１０％である。主軸速度変動による再生型の自励びびり抑制技術において、１回転前と現在の回転位置における速度差（速度変化率）が大きい程、びびり振動抑制効果が高いことが分かっている。よって、変動１周期当たりの速度変化率が高いほど、びびり抑制効果は高いといえる。 In FIGS. 8A to 8F, the spindle speed command S N (t) is 900 rpm, the speed clamp command S L (t) is 900 rpm, and the change conditions are the fluctuation amplitude A(t)=30% , frequency F(t)=10%. In regenerative self-excited chatter suppression technology using spindle speed fluctuations, it is known that the greater the speed difference (rate of change in speed) between the previous rotation and the current rotation position, the greater the chatter vibration suppression effect. Therefore, it can be said that the higher the rate of change in speed per fluctuation cycle, the higher the chatter suppression effect.
　図８Ａ及び図８Ｂの結果から、従来の方式では、変動１周期当たりの平均速度変化率（絶対値）は、約６．２％となる。図８Ｃ及び図８Ｄの結果から、第１実施形態の方式では、変動１周期当たりの平均速度変化率（絶対値）は、約１１％となる。図８Ｅ及び図８Ｆの結果から、第２実施形態の方式では、変動１周期当たりの平均速度変化率（絶対値）は、約１９％となる。したがって、速度変化率（すなわち、びびり抑制効果）は、従来の方式、第１実施形態の方式及び第２実施形態の方式の順に高くなることが分かる。 From the results of FIGS. 8A and 8B, in the conventional method, the average speed change rate (absolute value) per fluctuation cycle is about 6.2%. From the results of FIGS. 8C and 8D, in the method of the first embodiment, the average speed change rate (absolute value) per fluctuation cycle is about 11%. From the results of FIGS. 8E and 8F, in the method of the second embodiment, the average speed change rate (absolute value) per fluctuation cycle is approximately 19%. Therefore, it can be seen that the rate of change in speed (that is, chatter suppression effect) increases in the order of the conventional system, the system of the first embodiment, and the system of the second embodiment.
　また、加工能率については、旋削で一般に使われる毎回点送り（主軸が１回転当たりの送り量を指定し切削）の場合、主軸速度の変化に応じて送り量（切削にかかる時間が、ほぼ加工能率である）が変わる。よって、変動１周期当たりの平均主軸速度が高いほど、加工能率は高いといえる。 Regarding machining efficiency, in the case of point feed each time (cutting by specifying the feed amount per revolution of the main spindle), which is generally used in turning, the feed amount (the time required for cutting) changes according to the change in the spindle speed. efficiency) changes. Therefore, it can be said that the higher the average spindle speed per fluctuation cycle, the higher the machining efficiency.
　図８Ａの結果から、従来の方式では、変動１周期当たりの平均主軸速度は、約８３２ｒｐｍとなる。図８Ｃの結果から、第１実施形態の方式では、変動１周期当たりの平均主軸速度は、約７６５ｒｐｍとなる。図８Ｅの結果から、第１実施形態の方式では、変動１周期当たりの平均主軸速度は、約６３０ｒｐｍとなる。したがって、加工能率（すなわち、平均主軸速度）は、第２実施形態の方式、第１実施形態の方式及び従来の方式の順に高い。但し、従来の方式はびびり振動抑制効果が低いため、加工不可の可能性が高い。 From the result of FIG. 8A, in the conventional method, the average spindle speed per fluctuation cycle is about 832 rpm. From the result of FIG. 8C, in the method of the first embodiment, the average spindle speed per fluctuation cycle is approximately 765 rpm. From the result of FIG. 8E, in the method of the first embodiment, the average spindle speed per fluctuation cycle is approximately 630 rpm. Therefore, the machining efficiency (that is, the average spindle speed) is higher in the order of the system of the second embodiment, the system of the first embodiment, and the conventional system. However, since the conventional method is less effective in suppressing chatter vibration, there is a high possibility that machining will not be possible.
　以上、本発明の実施形態について説明したが、上記のモータ制御装置１０は、ハードウェア、ソフトウェア又はこれらの組み合わせにより実現することができる。また、上記のモータ制御装置１０により行なわれる制御方法も、ハードウェア、ソフトウェア又はこれらの組み合わせにより実現することができる。ここで、ソフトウェアによって実現されるとは、コンピュータがプログラムを読み込んで実行することにより実現されることを意味する。 Although the embodiment of the present invention has been described above, the motor control device 10 can be realized by hardware, software, or a combination thereof. Also, the control method performed by the motor control device 10 described above can be implemented by hardware, software, or a combination thereof. Here, "implemented by software" means implemented by a computer reading and executing a program.
　プログラムは、様々なタイプの非一時的なコンピュータ可読媒体（ｎｏｎ－ｔｒａｎｓｉｔｏｒｙ　ｃｏｍｐｕｔｅｒ　ｒｅａｄａｂｌｅ　ｍｅｄｉｕｍ）を用いて格納され、コンピュータに供給することができる。非一時的なコンピュータ可読媒体は、様々なタイプの実体のある記録媒体（ｔａｎｇｉｂｌｅ　ｓｔｏｒａｇｅ　ｍｅｄｉｕｍ）を含む。非一時的なコンピュータ可読媒体の例は、磁気記録媒体（例えば、ハードディスクドライブ）、光磁気記録媒体（例えば、光磁気ディスク）、ＣＤ－ＲＯＭ（Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒｙ）、ＣＤ－Ｒ、ＣＤ－Ｒ／Ｗ、半導体メモリ（例えば、マスクＲＯＭ、ＰＲＯＭ（Ｐｒｏｇｒａｍｍａｂｌｅ　ＲＯＭ）、ＥＰＲＯＭ（Ｅｒａｓａｂｌｅ　ＰＲＯＭ）、フラッシュＲＯＭ、ＲＡＭ（ｒａｎｄｏｍ　ａｃｃｅｓｓ　ｍｅｍｏｒｙ））を含む。 Programs can be stored and supplied to computers using various types of non-transitory computer readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical discs), CD-ROMs (Read Only Memory), CD-Rs, CD-R/ W, semiconductor memory (eg, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)).
　また、上述した各実施形態は、本発明の好適な実施形態ではあるが、上記各実施形態のみに本発明の範囲を限定するものではなく、本発明の要旨を逸脱しない範囲において種々の変更を施した形態での実施が可能である。 In addition, although each of the above-described embodiments is a preferred embodiment of the present invention, the scope of the present invention is not limited to only the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. It is possible to implement it in the form applied.
　１　工作機械
　２　数値制御装置
　１０　モータ制御装置
　１１　変動指令計算部
　１２　速度制御部
　１３　電流制御部
　１４　電流検出部
　１８　主軸モータ
　１９　速度検出部
　２１　主軸速度指令
　２２　速度クランプ指令 REFERENCE SIGNS LIST 1 machine tool 2 numerical controller 10 motor controller 11 fluctuation command calculator 12 speed controller 13 current controller 14 current detector 18 spindle motor 19 speed detector 21 spindle speed command 22 speed clamp command

Claims (4)

  1. 　工作機械における主軸モータの速度指令及び前記主軸モータの回転速度を周期的に変動させるための変動条件に基づいて速度変動指令を生成する変動指令計算部を備え、
    　前記変動指令計算部は、
    　前記主軸モータの速度クランプ指令に応じて、前記速度変動指令の位相又は前記速度変動指令の速度指令を変更する、
    工作機械の制御装置。     A fluctuation command calculation unit for generating a speed fluctuation command based on a speed command for a spindle motor in a machine tool and a fluctuation condition for periodically fluctuating the rotation speed of the spindle motor,
    The fluctuation command calculation unit is
    changing the phase of the speed fluctuation command or the speed command of the speed fluctuation command according to the speed clamp command of the spindle motor;
    Machine tool controller.
  2. 　前記変動指令計算部は、
    　前記速度変動指令が、前記速度クランプ指令を超える場合、前記速度変動指令の位相を変更する、請求項１に記載の工作機械の制御装置。     The fluctuation command calculation unit is
    2. The controller for a machine tool according to claim 1, wherein the phase of said speed fluctuation command is changed when said speed fluctuation command exceeds said speed clamp command.
  3. 　前記変動指令計算部は、前記速度変動指令の最大振幅値が、前記速度クランプ指令を超える場合、前記速度変動指令の主軸速度指令を変更する、請求項１に記載の工作機械の制御装置。 3. The machine tool control device according to claim 1, wherein said fluctuation command calculation unit changes the spindle speed command of said speed fluctuation command when the maximum amplitude value of said speed fluctuation command exceeds said speed clamp command.
  4. 　前記速度クランプ指令は、前記工作機械の加工条件に応じて生成される、請求項１から３のいずれか一項に記載の工作機械の制御装置。 The machine tool control device according to any one of claims 1 to 3, wherein the speed clamp command is generated according to the machining conditions of the machine tool.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015134400A (en) * 2013-12-16 2015-07-27 国立大学法人 東京大学 Spindle motor control device
JP5823082B1 (en) * 2014-09-09 2015-11-25 三菱電機株式会社 Numerical controller
JP2020040148A (en) * 2018-09-07 2020-03-19 オークマ株式会社 Vibration suppression device and vibration suppression method of machine tool

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015134400A (en) * 2013-12-16 2015-07-27 国立大学法人 東京大学 Spindle motor control device
JP5823082B1 (en) * 2014-09-09 2015-11-25 三菱電機株式会社 Numerical controller
JP2020040148A (en) * 2018-09-07 2020-03-19 オークマ株式会社 Vibration suppression device and vibration suppression method of machine tool

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