PH12018000005A1

PH12018000005A1 - Motor control apparatus

Info

Publication number: PH12018000005A1
Application number: PH12018000005A
Authority: PH
Inventors: Yuji Ide; Toshio Hiraide; Michio Kitahara
Original assignee: Sanyo Electric Co
Priority date: 2017-01-20
Filing date: 2018-01-05
Publication date: 2018-08-20
Also published as: JP2018116600A; CN108336940B; CN108336940A; TWI783961B; TW201841085A; JP6846213B2; PH12018000005B1

Abstract

A motor control apparatus that controls a motor of a dual inertia system, the motor control apparatus includes: a speed controller that controls the motor in a direction in which a deviation between a speed command value and a speed feedback value becomes zero; and an inertia ratio compensation filter disposed in an output side of the speed controller. The inertia ratio compensation filter gently compensates increase and decrease of gains at an antiresonance frequency and a resonance frequency regarding at least one set of an antiresonance characteristic and a resonance characteristic of the motor of the dual inertia system as a controlled object, the inertia ratio compensation filter setting phase delays at the antiresonance frequency and the resonance frequency to a phase margin or less.

Description

motor of the dual inertia system as a controlled object, the inertia ratio compensation filter setting phase delays at the antiresonance frequency and the resonance frequency to a phase margin (40° to 60°) or less.

In the present motor control apparatus, the inertia ratio compensation filter may include a biquadratic filter and a phase advance filter.

In the present motor control apparatus, the biquadratic filter may be configured to gently compensate increase and decrease of the gains at the antircsonance frequency and the resonance frequency regarding at least one set of the antiresonance characteristic and the resonance characteristic of the motor of the dual inertia system as the controlled object.

In the present motor control apparatus, the phase margin may be 40° to 60°.

In the present motor control apparatus, the phase advance filter may be configured to advance the phase at a frequency 1.5 to 5 times higher than the resonance frequency.

In the present motor control apparatus, the phase advance filter may be configured to restrain the phase delay by the inertia ratio compensation filter at the frequency slightly lower than the antiresonance frequency or advance the phase at this frequency to restrain the hump of the closed-loop frequency characteristic from occurring and advance the phase at the frequency slightly higher than the resonance frequency.

The inertia ratio compensation filter may include, for example, the biquadratic filter and the phase advance filter. The biquadratic filter may be configured to cancel only the characteristic of the antiresonance frequency of the mechanical system.

This ensures stabilizing the operation of the motor when the motor with the large inertia ratio is driven.

According to the disclosure, it is configured to stabilize the operation of the motor when the motor with the large inertia ratio is driven.BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1A is a function block diagram illustrating one exemplary configuration of a system that controls a motor that processes a mechanical system constituted by a dual inertia system, and Fig. 1B is a function block diagram illustrating one exemplary configuration of an inertia ratio compensation filter of a motor control apparatus;

Fig. 2 is a drawing illustrating an example of a frequency characteristic of a biquadratic filter;

Fig. 3 is a drawing illustrating an example of a frequency characteristic of a phase advance filter;

Fig. 4 is a drawing illustrating an example of a frequency characteristic of an inertia ratio compensation filter;

Figs. SA and 5B illustrate advantageous effects when a compensation filter according to the embodiment is applied (inserted) to the motor control apparatus of the mechanical system having an antiresonance frequency of 100 Hz and a resonance frequency of 150 Hz, Fig. 5A illustrates an example without the compensation filter, and Fig. 5B illustrates an example with the compensation filter;

Fig. 6 illustrates a frequency dependency of a speed control gain and a phase in the dual inertia system;

Fig. 7A illustrates the frequency dependency of the speed control gain in the dual inertia system when an inertia ratio is small, and Fig. 7B illustrates the frequency dependency of the speed control gain in the dual inertia system when an inertia ratio is high; and

Fig. 8A illustrates a characteristic of an inverse function of a dual inertia system disclosed in JP-A-2000-322105, and Fig. 8B illustrates a characteristic when a filter that reduces delays of phases at the antiresonance frequency and the resonance frequency is attempted to be inserted. ;

DESCRIPTION OF THE EMBODIMENTS

In the following detailed description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

The following describes a motor control apparatus according to one embodiment of the disclosure in details with reference to the drawings.

A system A illustrated in Fig. 1A is one example of a system that controls a motor that processes a mechanical system constituted by a dual inertia system and includes a motor control apparatus B according to the embodiment. This motor control apparatus B controls a motor 1a. The motor (the motor of the dual inertia system) la . drives a mechanical system 1b constituted by the dual inertia system. Fig. IBisa function block diagram illustrating one exemplary configuration of an inertia ratio compensation filter 5 included in the motor control apparatus B.

As illustrated in Fig. 1A, the motor control apparatus B includes a speed controller 3, the inertia ratio compensation filter 5, a torque controller 7, an encoder 11, a speed calculator (s) 15, and a subtractor. It may be considered that the subtractor is included in the speed controller 3.

In the motor control apparatus B, the speed controller 3, for example, controls the motor 1a in a direction in which a deviation between a speed command value and a speed feedback value becomes zero. That is, the speed controller 3, for example, generates and outputs a torque command with which the deviation between the speed command value and the speed feedback value becomes zero based on a speed command and a speed feedback output from the speed calculator (s) 15.

The speed command and the speed feedback (or a difference between the speed command and the speed feedback) are passed through the speed controller 3. The speed controller 3 outputs the torque command to the torque controller 7 via the inertia ratio compensation filter 5.

The torque controller 7, for example, generates a control command based on the torque command and outputs the control command to the motor 1a. This drives the motor la. The encoder 11 encodes a rotation position of the motor 1a to generate and output a position feedback. The speed calculator (s) 15, for example, calculates a speed (for example, a rotation speed of the motor) based on the position feedback to generate the speed feedback. The speed calculator (s) 15 returns (outputs) the speed feedback to the speed controller 3 (or the subtractor at a former stage of the speed controller 3).

In the embodiment, the inertia ratio compensation filter 5 can be constituted by combining a biquadratic filter 5-1 that cancels only a characteristic of an antiresonance frequency of the mechanical system 1b and a phase advance filter 5-2 as illustrated in

Fig. 1B.

The inertia ratio compensation filter 5, for example, gently compensates increase and decrease of gains at the antiresonance frequency and the resonance frequency regarding at least one set of an antiresonance characteristic and a resonance characteristic of the motor 1a and sets phase delays at the antiresonance frequency and the resonance frequency to a phase margin or less.

The biquadratic filter 5-1, for example, gently compensates increase and decrease of gains at the antiresonance frequency and the resonance frequency regarding at least one set of an antiresonance characteristic and a resonance characteristic of the motor la.

The phase advance filter 5-2, for example, advances a phase at a frequency 1.5 to 5 times higher than the resonance frequency. Furthermore, the phase advance filter 5-2, for example, restrains (or prevents) a phase delay by the compensation filter (the inertia ratio compensation filter 5) at a frequency slightly lower than the antiresonance frequency or restrains (or prevents) a hump of a closed-loop frequency characteristic from occurring by advancing the phase at this frequency, and advances the phase at a frequency slightly higher than the resonance frequency.

For example, a transfer function G of the inertia ratio compensation filter 5 can be the following transfer function.

G=G1 x Gy

Gi = (s? + 2Cuwns + ord)/(s?* + 20 oLs + or?) oon’

G2 = {(1 +sT1)/(1 + sT2)}?

Here, Gj is a transfer function of the biquadratic filter 5-1. The "s" isa

Laplace operator. The "ow," and "wn" are natural angular frequencies. The "CL" and "Cu" are attenuation coefficients. For example, "oL" is set to the antiresonance frequency of the mechanical system 1b and "on" is set to the resonance frequency of the mechanical system 1b. Furthermore, setting Cu = 0.5 prevents or restrains a gain reduction at the resonance frequency of the mechanical system 1b. Setting {1 = approximately 0.1 to 0.01 compensates a gain decrease at the antiresonance frequency of the mechanical system 1b to some extent.

Gz is a transfer function of the phase advance filter 5-2. (1/T1) <(1/T2). A ratio of T) to Tz is set such that a gain increase in a high frequency domain becomes approximately identical to a gain decrease in the high frequency domain by the biquadratic filter 5-1. Phase delay by the inertia ratio compensation filter 5 at the antiresonance frequency and the resonance frequency are set to a phase margin or less.

The phase margin is, for example, 40° to 60°.

This eliminates (or decreases) the phase delay by the inertia ratio compensation filter 5 at the frequency slightly lower than the antiresonance frequency or the phase at this frequency is slightly advanced. The phase delays at the antiresonance frequency and the resonance frequency are set to 90° or less. Furthermore, the phase at the . frequency slightly higher than the resonance frequency is advanced.

Fig. 2 illustrates an example of a frequency characteristic of the biquadratic filter 5-1 (the transfer function Gi) set as described above. Fig. 3 illustrates an example of a frequency characteristic of the phase advance filter 5-2 (the transfer function Gz) set as described above. Fig. 4 illustrates an example of a frequency characteristic of the inertia ratio compensation filter 5 (the transfer function G) set as described above.

As illustrated in Fig. 4, the inertia ratio compensation filter 5 (the transfer function G) advances the phase at, for example, equal to or less than a frequency 10% lower than the antiresonance frequency of the mechanical system 1b. In the gain characteristic of the biquadratic filter 5-1, a frequency dependency of the gain is gentle (1) in Fig. 4) compared with a typical one as illustrated in Fig. 6. In addition, the phase delays at the antiresonance frequency and the resonance frequency are little less than 40° (2) in Fig. 4). Furthermore, the phase is advanced at the frequency 1.5 to 5 times higher than the resonance frequency (3) in Fig. 4).

CE

The inertia ratio compensation filter 5 having the transfer function G according to the embodiment having these features ensures restraining a resonance at a frequency higher than the resonance frequency by advancing the phase of the portion (for example, the high frequency domain where the speed control gain increases) even when the inerlia ratio of the motor la increases and the speed control gain in the high frequency domain increases. In view of this, a motor operation stabilizes. The phase delays at the inertia ratio compensation filter 5 in the antiresonance frequency and the resonance frequency are set to as small as the phase margin (40° to 60°) or less. In view of this, even when the antiresonance frequency and the resonance frequency of the mechanical system 1b vary by approximately 5%, the oscillation can be prevented or restrained from occurring.

Figs. 5A and 5B illustrate advantageous effects when the inertia ratio compensation filter 5 according to the embodiment is applied (inserted) to the motor control apparatus B of the mechanical system 1b having an antiresonance frequency of

I5 100 Hz and a resonance frequency of 150 Hz. As illustrated in Fig. 5A, when the motor control apparatus B does not include the inertia ratio compensation filter 5, for example, a hump 21 near 55 Hz becomes large in the motor control apparatus B of the mechanical system 1b. A resonance 23 is seen at 400 Hz. In the case in which the motor la is operated in such a state, the operation is not stabilized. As illustrated in

Fig. 5B, when the motor control apparatus B includes the inertia ratio compensation filter 5 having the gain characteristic and the phase characteristic as illustrated in Fig. 4 (when the inertia ratio compensation filter 5 is inserted between the speed controller 3 and the torque controller 7), a hump 21a at 55 Hz is restrained in a decreasing direction.

Furthermore, a resonance 23a at 400 Hz is restrained. As a result, a cutoff frequency inacontrol band can be increased.

As described above, in the embodiment, the inertia ratio compensation filter 5 is constituted by combining the biquadratic filter that cancels only the characteristic of the antiresonance frequency of the mechanical system 1b and the phase advance filter.

Using this inertia ratio compensation filter 5 ensures obtaining the following advantageous effects.

When the motor 1a with a large inertia ratio is driven, the phase delay by the compensation filter (the inertia ratio compensation filter 5) at the frequency slightly lower than the antiresonance frequency is prevented or restrained, or the phase at this frequency is advanced. This prevents or restrains the hump of the closed-loop frequency characteristic from occurring. Simultaneously, the phase at the frequency slightly higher than the resonance frequency is advanced by the inertia ratio compensation filter 5 (the phase advance filter 5-2). This ensures preventing or restraining the oscillation at the resonance frequency from occurring.

Furthermore, the phase delays by the compensation filter at the antiresonance frequency and the resonance frequency are set to the phase margin (40° to 60°) or less.

This ensures preventing or restraining the oscillation from occurring even when the antiresonance frequency and/or the resonance frequency of the mechanical system 1b slightly vary. The speed control gin decrease at the antiresonance frequency and the speed control gain increase at the resonance frequency of the mechanical system 1b are compensated to some extent, for example, gently. As a result, even when the inertia ratio is large, a high response of the speed control system can be made.

Accordingly, a shortened acceleration and deceleration time by decreasing the motor inertia is achieved. Furthermore, when the acceleration and deceleration time is identical, a reduced motor cost by reducing the motor output torque is achieved. This ensures providing the motor control apparatus B that achieves both a shortened cycle time and high accuracy of the machine at the same time.

The configuration of the above-described embodiment is not limited to the configuration and the like illustrated in the attached drawings. The embodiment can be appropriately changed within a range where the advantageous effect of the embodiment isprovided. Other than that, thc embodiment can be appropriately changed and executed without departing from a range of the object of the embodiment.

Each of components of the embodiment can be arbitrarily sorted out. The embodiment includes an embodiment that includes the configuration sorted out.

Regarding the industrial applicability, the disclosure is applicable to a motor control apparatus.

The motor of the dual inertia system may be, for example, a motor that drives a mechanical system constituted by the dual inertia system. The phase delay by the filter can be expressed as the delay of the filter. The gains and the phases illustrated in Figs. 2, 3, 4, and 5 may be gains and phases of the torque command output from the speed controller 3.

In the configuration illustrated in Figs. 1A and 1B, while setting oL to the antiresonance frequency of the mechanical system and setting wn to the resonance frequency of the mechanical system, setting {ux = 0.5 may eliminate the gain reduction at the resonance frequency of the mechanical system. Setting {1 = approximately 0.1 to 0.01 may compensate the gain decrease at the antiresonance frequency of the mechanical system to some extent. The inertia ratio compensation filter 5 may be configured by combining the biquadratic filter 5-1 and the phase advance filter 5-2 that cancel only the characteristic of the antiresonance frequency of the mechanical system 1b as illustrated in Fig. 1B.

The ratio of Ti to T2 may be set such that a gain increase in a high frequency domain becomes approximately identical to the gain decrease in the high frequency domain of the biquadratic filter. Phase delays of the inertia ratio compensation filter at the antiresonance frequency and the resonance frequency may be set to a phase margin or less. Thus, the phase delay of the inertia ratio compensation filter 5 at the frequency slightly lower than the antiresonance frequency may be eliminated or slightly advanced.

In this embodiment, using the inertia ratio compensation filter 5 ensures obtaining the following advantageous effects. When the motor with a large inertia ratio is driven, the phase delay of the compensation filter at the frequency slightly lower than the antiresonance frequency is eliminated or advanced to prevent the hump of the closed-loop frequency characteristic from occurring. Simultaneously, advancing the phase of the compensation filter at the frequency slightly higher than the resonance frequency prevents the oscillation at the resonance frequency from occurring.

The embodiment of the disclosure may be the following first to sixth motor control apparatuses.

The first motor control apparatus is a motor control apparatus that controls a motor of a dual inertia system and includes a speed controller that controls the motor in a direction in which a deviation between a speed command value and a speed feedback value becomes zero. The motor control apparatus includes an inertia ratio compensation filter that gently compensates gains with respect to an antiresonance frequency and a resonance frequency regarding at least one set of an antiresonance characteristic and a resonance characteristic of the motor of the dual inertia system of a controlled object, the inertia ratio compensation filter setting phase delays at the antiresonance frequency and the resonance frequency to a phase margin or less, the inertia ratio compensation filter being disposed in an output side of the speed controller.

In the second motor control apparatus according to the first motor control

Co apparatus, the inertia ratio compensation filter includes a biquadratic filter and a phase advance filter.

In the third motor control apparatus according to the second motor control apparatus, the biquadratic filter gently compensates gains with respect to an antiresonance frequency and a resonance frequency regarding at least one set of an antiresonance characteristic and a resonance characteristic of the motor of the dual inertia system of a controlled object.

In the fourth motor control apparatus according to the second or third motor control apparatus, the phase margin is 40° to 60°.

In the fifth motor control apparatus according to the fourth motor control apparatus, the phase advance filter further advances a phase at a frequency 1.5 to 5 times higher than a resonance frequency.

In the sixth motor control apparatus according to the fourth motor control apparatus, the phase advance filter eliminates or advances a phase delay of a compensation filter at a frequency slightly lower than an antiresonance frequency to prevent a hump of a closed-loop frequency characteristic from occurring and advances a phase of the compensation filter at a frequency slightly higher than a resonance frequency.

The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims appended hereto.

er ———————

I

MOTOR CONTROL APPARATUS

BACKGROUND

1. Technical Field

The present embodiment disclosed herein relates to a motor control technique. 2. Description of the Related Art

A machine tool performs conversion of a rotational motion of a motor to a linear motion using a ball screw to drive a table. In such a power transmission mechanism, a dual inertia system is constituted by a portion with a low rigidity, such as the ball screw.

For example, as illustrated in Fig. 6, the dual inertia system has an antiresonance frequency near 100 Hz and a resonance frequency near 140 Hz. A phase from the antiresonance frequency to the resonance frequency advances by 180°.

In such a dual inertia system, decreasing a motor inertia increases a ratio of a load side inertia to a motor side inertia. In a frequency characteristic from a torque command to a speed when a speed loop is configured, as illustrated in Figs. 7A and 7B, a difference between a gain at equal to or less than the antiresonance frequency and a gain at equal to or more than the resonance frequency becomes large (Fig. 7B) compared with a case in which an inertia ratio is small (Fig. 7A).

Adjusting a speed control gain such that the gains at equal to or less than the antiresonance frequency become identical increases the gain at equal to or more than the resonance frequency. In view of this, when a gain margin and a phase margin at a frequency equal to or more than the resonance frequency is not ensured in addition to a J gain margin and a phase margin at a frequency equal to or less than the antiresonance :

I frequency, a control system becomes unstable and an oscillation occurs.

In view of this, typically, the speed control gain has been decreased in order to ensure stability when a motor with a large inertia ratio is driven.

However, there is a problem that the low speed control gain deteriorates process accuracy. With an identical motor torque, all inertia being small shortens a time that takes to accelerate and decelerate. In view of this, in order to shorten a cycle time of a machine, the motor inertia is decreased.

JP-A-2000-322105 discloses an exemplary technique to improve a characteristic of the dual inertia system. A servo control apparatus described in this document includes a speed controller. This speed controller controls a servo motor so that a difference between a speed command value and a speed feedback value becomes ‘azero. The speed controller is incorporated with a filter. This filter has characteristics that are reverses of, or approximate the reverses of, at least one set of antiresonance characteristics and resonance characteristics of a controlled object. This ensures stabilizing by suppressing the gain at a resonance peak, while suppressing the increase in phase delay in low region as much as possible, to stably raise the speed control gain of the speed control system.

JP-A-2005-328607 discloses an example of a technique that ensures its stability with respect to a variation of an inertia moment. In a motor control apparatus described in this document, a motor is coupled to a mechanical load whose inertia moment varies from a minimum value to a maximum value. The motor control apparatus drivingly controls the motor based on a speed command signal and has a speed loop. The motor control apparatus drives the motor in accordance with a signal of a deviation between the speed command signal and a speed detection signal of the motor. Furthermore, the motor control apparatus includes speed control means and

TTT OO compensation control means. The speed control means performs a proportional control operation and an integral control operation with respect to deviation signal to generate and output a motor driving command. The compensation control means is inserted in the speed loop in series with the speed control means. This compensation control means is set such that a phase of a speed open loop at a frequency between a first crossover frequency and a second crossover frequency becomes —140° or more.

The first crossover frequency is a crossover frequency of the speed open loop that is an opened speed loop when the inertia moment becomes a minimum value. The second crossover frequency is a crossover frequency of the speed open loop when the inertia moment becomes a maximum value. The compensation control means is a phase advance filter. This phase advance filter has a phase advance characteristic in which the phase advances in an intermediate frequency domain and the phase becomes approximately zero in a low frequency domain and a high frequency domain.

In the technique in JP-A-2000-322105, the control system includes the filter that cancels the antiresonance frequency and the resonance frequency of the mechanical system constituted by the dual inertia system, thereby improving the characteristic.

However, the filter with the characteristics that are reverses of the one set of antiresonance characteristics and resonance characteristics of the controlled object (the dual inertia system) used in the technique in JP-A-2000-322105 has a characteristic in which a change between phases at the antiresonance frequency and the resonance frequency becomes steep as illustrated in Fig. 8A. A phase delay from the antiresonance frequency to the resonance frequency becomes 180°.

A phase advances by 180° from the antiresonance frequency to the resonance frequency as a characteristic of the dual inertia system. In view of this, when the antiresonance frequency and the resonance frequency of the mechanical system completely match an antiresonance frequency and a resonance frequency set in a compensation filter, the oscillation is less likely to occur, thereby improving the characteristic. However, when a displacement occurs even slightly between the antiresonance frequency set in the compensation filter and the antiresonance frequency of the mechanical system, there is a problem of the oscillation occurrence due to a large rapid phase delay by the compensation filter.

When the phase delays by 180°, a signal is invertedly output. In view of this, when a control loop is configured, the oscillation occurs. Similarly in the resonance frequency, when a displacement occurs even slightly between the resonance frequency set in the compensation filter and the resonance frequency of the mechanical system, there is a problem of the oscillation occurrence due to a large rapid phase delay by the compensation filter.

The mechanical system that uses the ball screw has the following problems.

A torsional rigidity of the ball screw slightly varies depending on a position of the table.

In view of this, the antiresonance frequency and the resonance frequency are slightly changed depending on the position of the table and the oscillation occurs. In this case, the compensation filter fails to be inserted, thereby failing to increase the speed control gain.

For example, as illustrated in Fig. 8B, the following problem occurs when a filter that reduces delays of phases at the antiresonance frequency and the resonance frequency is attempted to be inserted. A phase delay at a frequency slightly lower than the antiresonance frequency increases a hump of a closed-loop frequency characteristic.

Furthermore, a phase delay at a frequency slightly higher than the resonance frequency eliminates a phase margin to cause an oscillation. The increase of the hump and the occurrence of the oscillation deteriorate process accuracy. »

The technique in JP-A-2005-328607 uses a phase advance filter to decrease a phase delay near a crossover frequency when an inertia moment of a mechanical load is at maximum. This ensures obtaining a preferable control characteristic in which a phase margin becomes 40° or more even when the inertia moment of the mechanical load varies.

However, the technique in JP-A-2005-328607 only decreases the phase delay near the crossover frequency when the inertia moment of the mechanical load is at maximum. This technique does not improve the characteristic of the dual inertia system that has the portion with the low rigidity in the mechanical load.

With a method in JP-A-2005-328607, a filter having a characteristic that reduces a speed control gain in a low frequency domain is used as a phase advance filter. In view of this, when this method is applied to a machine with a large inertia ratio in which the portion with the low rigidity exists to try to advance the phase near the resonance frequency, there is a problem that the speed control gain in a control band decreases to degrade a control characteristic.

SUMMARY

The disclosure is made in order to solve the problems as described above. An object of the disclosure is, when a motor with a large inertia ratio is driven in a dual inertia system, further stabilizing an operation of the motor.

The disclosure includes the following configurations. 1) A phase delay by a compensation filter at a frequency slightly lower than an antiresonance frequency is prevented or restrained, or a phase at this frequency is advanced. This prevents or restrains a hump of a closed-loop frequency characteristic from occurring. 2) Simultaneously, a phase at a frequency slightly higher than the resonance frequency is advanced by the compensation filter. This ensures preventing or restraining the oscillation at the resonance frequency from occurring. 3) Furthermore, the phase delays by the compensation filter at the antiresonance frequency and the resonance frequency are set to the phase margin (40° to 60°) or less.

This ensures preventing or restraining the oscillation from occurring even when the antiresonance frequency and/or the resonance frequency of the mechanical system slightly vary.

The gain decrease at the antiresonance frequency and the gain increase at the resonance frequency of the mechanical system are compensated to some extent, for example, gently. As a result, even when the inertia ratio is large, a high response of the speed control system can be made.

Accordingly, a shortened acceleration and deceleration time by decreasing the motor inertia is achieved. Furthermore, when the acceleration and deceleration time is identical, a reduced motor cost by reducing the motor output torque is achieved. This ensures providing the motor control apparatus that achieves both a shortened cycle time and high accuracy of the machine at the same time.

According to one aspect of the present disclosure, the following motor control apparatus (the present motor control apparatus) is provided. The present motor control apparatus includes: a speed controller that controls the motor in a direction in which a deviation between a speed command value and a speed feedback value becomes zero; and an inertia ratio compensation filter disposed in an output side of the speed controller. The inertia ratio compensation filter gently compensates increase and decrease of gains at an antiresonance frequency and a resonance frequency regarding at least one set of an antiresonance characteristic and a resonance characteristic of the

Claims

vy , CLAIMS:

1. A motor control apparatus that controls a motor of a dual inertia system, the motor control apparatus comprising: a speed controller that controls the motor in a direction in which a deviation between a speed command value and a speed feedback value becomes zero; and an inertia ratio compensation filter disposed in an output side of the speed controller, wherein the inertia ratio compensation filter gently compensates increase and decrease of gains at an antiresonance frequency and a resonance frequency regarding at least one set of an antiresonance characteristic and a resonance characteristic of the motor of the dual inertia system as a controlled object, the inertia ratio compensation filter setting phase delays at the antiresonance frequency and the resonance frequency to a phase margin or less.

2. The motor control apparatus according to claim 1, wherein the inertia ratio compensation filter includes a biquadratic filter and a phase advance filter.

3. The motor control apparatus according to claim 2, wherein the biquadratic filter gently compensates increase and decrease of gains at an antiresonance frequency and a resonance frequency regarding at least one set of an antiresonance characteristic and a resonance characteristic of the motor of the dual inertia system as a controlled object.

4 The motor control apparatus according to claim 2 or 3, wherein the phase margin is 40° to 60°.

5. The motor control apparatus according to claim 4, wherein the phase advance filter advances a phase at a frequency 1.5 to 5 times higher than a resonance frequency.

6. The motor control apparatus according to claim 4, wherein the phase advance filter restrains a phase delay by the inertia ratio compensation filter at a frequency slightly lower than an antiresonance frequency or advances the phase at this frequency to restrain a hump of a closed-loop frequency characteristic from occurring and advances a phase at a frequency slightly higher than a resonance frequency.