JP4394086B2 - Stepping motor drive device - Google Patents

Description

  The present invention relates to a stepping motor drive device capable of suppressing motor vibration generated in a middle / high speed range.

  Stepping motors have the drawback of generating large vibrations in the middle and high speed range. To drive the mechanical load with high accuracy in the speed range, use mechanical and electrical dampers. It becomes indispensable to suppress vibration.

An example of an electrical damper is as follows. That is, the position detection signal output from the resolver provided in the stepping motor is demodulated, and the correction amount of the excitation phase of the stator magnetic pole of the stepping motor is calculated based on the difference in speed between the demodulated signal and the position command signal. A signal obtained by adding the correction amount to the position command signal is supplied to the stepping motor as an exciting current via a power amplifier (for example, Patent Document 1).
Japanese Patent Laid-Open No. 2000-4598

  However, in the case of the conventional example described above, the overall configuration is complicated, and a high-resolution resolver, a high-speed processor, and the like are required, and there is a drawback that it is very difficult to reduce the cost.

  The present invention has been created under the above-mentioned background, and the object of the present invention is to sufficiently suppress vibrations in the middle and high speed ranges despite the fact that the overall configuration is very simple. An object of the present invention is to provide a driving device for a stepping motor that can be used.

The stepping motor drive device of the present invention includes an input terminal to which an input pulse as an operation command of the stepping motor and an encoder pulse indicating the rotation amount of the stepping motor are input, and the encoder pulse or its multiplication in one cycle of the input pulse. or counting the dividing pulses is compared with the count value and the reference value, a motor abnormality detecting section for outputting the comparison result as uneven rotation detection signal, the rotation unevenness detection signal, rotation of the stepping motor is input When the phase shifts in comparison with the pulse and indicates abnormal rotation unevenness, the motor vibration suppression unit that delays the phase of the input pulse to suppress the rotation unevenness, and the input pulse derived from the motor vibration suppression unit And a power supply unit that generates each phase current for driving the stepping motor. In place of the motor vibration suppression unit, when the rotation unevenness detection signal indicates that the rotation of the stepping motor is delayed in phase with respect to the input pulse, the rotation unevenness is abnormal. It is also possible to use a structure that can be advanced to suppress this.

  For the motor vibration suppression unit, a phase adjuster that adjusts the phase of the input pulse, and the input pulse and the input pulse that is phase-adjusted by the phase adjuster are input, and both signals are input according to the rotation unevenness detection signal. It is preferable to use a configuration having a selector for selecting and outputting.

  In the case of the stepping motor driving device according to the present invention, the rotation unevenness of the stepping motor is detected according to the counting result of the encoder pulse of one cycle of the input pulse, and when the rotation unevenness is detected, The phase is adjusted. Unlike the case of the conventional example, it is possible to sufficiently suppress the vibration in the middle and high speed range of the stepping motor without using a high resolution resolver, a high speed processor or the like. In addition, since the overall configuration is very simple, the cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a stepping motor driving device, FIG. 2 is a circuit diagram of a motor vibration suppression unit, FIG. 3 is a timing chart showing various signal waveforms of a motor abnormality detection unit, and FIG. FIG. 5 is a result of an experiment when a five-phase stepping motor is driven, and is a graph showing characteristics of the rotational speed and vibration level of the motor. FIG. 6 is a case where a two-phase stepping motor is driven. 6 is a graph showing the characteristics of the rotational speed and vibration level of the motor.

  The stepping motor driving device A listed here is a device that is connected between a controller or the like and a stepping motor B as shown in FIG. 1 and drives the stepping motor B according to an input pulse a input from the controller or the like. .

  Specifically, the stepping motor driving apparatus A includes an input terminal 10 to which an input pulse a which is an operation command of the stepping motor B and an encoder pulse b indicating the rotation amount of the stepping motor B are input, and one cycle of the input pulse a. The pulse obtained by multiplying the encoder pulse b is counted, the count value e is compared with the reference value e0, and the motor abnormality detection unit 20 that outputs the comparison result as the rotation unevenness detection signal c, and the rotation unevenness detection signal c is stepped. The motor vibration suppression unit 30 that adjusts the phase of the input pulse a to suppress the rotation unevenness of the stepping motor B when the rotation unevenness of the motor B is indicated, and the input pulse derived from the motor vibration suppression unit 30 and a power supply unit 40 for generating each phase current f for driving the stepping motor B based on d.

  For the stepping motor B, a 5-phase stepping motor with a rotary encoder is used. In this, an incremental rotary encoder is connected in advance to the shaft of a five-phase stepping motor. When a power supply voltage is separately supplied to the rotary encoder, the rotation amount of the motor is changed to the A phase and B phase pulses b1 and b2. And this is output as an encoder pulse b.

  The motor abnormality detection unit 20 is a digital circuit that combines a counter and the like, and multiplies the encoder pulse b at the timing when the input pulse a rises and sequentially counts, and holds the count result until the timing when the input pulse a rises next. The count value e of the up / down counter 21 is compared with the preset reference value e0 at the timing when the input pulse a rises, and when the count value e is equal to or greater than the reference value e0 A comparison unit 22 is provided that generates a signal at the L level when the H level is less than the reference value e0 and outputs the signal to the motor vibration suppression unit 30 as a rotation unevenness detection signal c.

  The up / down counter 21 has a function of detecting the rotation direction of the stepping motor B by detecting the phase between the A-phase pulse b1 and the B-phase pulse b2 included in the encoder pulse b. When it indicates normal rotation, it operates as an up-counter. Conversely, when it indicates reverse rotation, it operates as a down-counter. The comparison unit 22 is a comparison circuit in which a gate circuit is combined, and the output signal is a rotation unevenness detection signal c.

  The motor vibration suppression unit 30 is a circuit connected between the input terminal 10 and the power supply unit 40, and has a configuration as shown in FIG. That is, the phase adjuster 31 that adjusts the phase of the input pulse a, the input pulse a and the input pulse a ′ that is phase-adjusted by the phase adjuster 31 are input, and both signals correspond to the rotation unevenness detection signal c. And a selector 32 that outputs this as an input pulse d.

  Here, a signal delay circuit is used as the phase adjustment unit 31. The time constant varies depending on the type of the stepping motor B and the like, and a value that can sufficiently suppress vibration in the middle / high speed range may be obtained by experiments and set as appropriate.

  The power supply unit 40 excites the power supply circuit that rectifies the input commercial alternating current to generate a motor current, the constant current control circuit that controls the motor current at a constant value, and each phase coil of the stepping motor B in a predetermined excitation sequence. Therefore, a phase distribution circuit that generates a phase distribution signal based on an input pulse d and a bipolar switching element group that switches based on a phase distribution signal, the motor current that is made constant current is switched for each phase. And an inverter circuit that generates each phase current f.

  The operation of the stepping motor driving apparatus configured as described above will be described with reference to FIGS.

  When vibration occurs even though the rotation speed of the stepping motor B is constant, rotation unevenness occurs in the stepping motor B, and accordingly, the period of the encoder pulse b becomes longer or shorter.

  FIG. 5A shows the measurement results of the characteristics of the rotational speed and vibration level of the stepping motor B when the stepping motor B is driven using a general device. As is clear from the figure, the vibration level is high in the medium speed range of 2 to 4 kHz and the high speed range of 9 kHz except for the low speed range.

  The count value e of the up / down counter 21 of the motor abnormality detector 20 indicates the number of encoder pulses b multiplied in one cycle of the input pulse a, and is proportional to the ratio of the cycle of the input pulse a and the encoder pulse b. It is the value. Therefore, when vibration is generated in the stepping motor B and no rotation unevenness occurs, the rotation is constant regardless of the number of rotations. When the vibration occurs in the stepping motor B and the rotation unevenness occurs, it changes irregularly. Will do.

  In the present embodiment, as shown in FIG. 3, when the stepping motor B rotates at a constant speed without vibration, the resolution of the encoder, the multiplication factor of the up / down counter 21, etc. are set so that the count value e becomes 4. The reference value e0 is set to 5. The time constant of the phase adjustment unit 31 is set to 4.63 μS.

  Accordingly, as shown in FIG. 3, the rotation unevenness detection signal c becomes L level during the period when the count value e is less than 5, and at this time, the input pulse a is selected by the selector 32 as shown in FIG. is output as d. On the other hand, as shown in FIG. 3, the rotation unevenness detection signal c becomes H level during the period in which the count value e is 5 or more. At this time, the input pulse a ′ is selected by the selector 32 as shown in FIG. Is output as

  Each phase current f is generated by the power supply unit 40 based on such an input pulse d, and the stepping motor B is driven. During the period when the rotation unevenness detection signal c is at the H level, the rotation of the stepping motor B is in a phase advance compared to the input pulse a, but is adjusted so that the phase of the input pulse d is automatically delayed. Therefore, the rotation unevenness of the stepping motor B is corrected, and as a result, the vibration of the stepping motor B is suppressed.

  Note that the period in which the rotation unevenness detection signal c is at the L level includes not only the state in which the stepping motor B has no rotation unevenness but also the state in which the rotation is delayed in phase with respect to the input pulse a. However, in connection with the use of the phase delay circuit as the phase adjustment unit 31, the phase adjustment of the input pulse d is not performed during this period.

  FIG. 5B shows the measurement results of the characteristics of the rotational speed and vibration level of the stepping motor B when the proposed apparatus A is driven. It has been proved that the vibration level is sufficiently suppressed in the medium speed range of 2 to 4 kHz and the high speed range of 9 kHz except for the low speed range.

  Thus, it becomes possible to sufficiently suppress the vibration in the middle and high speed range of the stepping motor B without using a high resolution resolver, a high speed processor, or the like. In addition, the entire configuration including the use of a phase delay circuit as the phase adjustment unit 31 is very simple, and accordingly, the cost can be reduced.

  In the present embodiment, the case where a five-phase stepping motor is driven as the stepping motor B has been described as an example. However, the present invention can also be applied to other types of stepping motors. It is only necessary to change the design of the excitation sequence pattern and the like as appropriate.

  FIG. 6A shows the measurement results of the characteristics of the rotational speed and vibration level of the two-phase stepping motor when it is driven using a general device. As is clear from the figure, the vibration level is very high in the speed region of 1 kHz or more except for the low speed region, and it is impossible to continue driving due to the temperature rise.

  FIG. 6B shows the measurement results of the characteristics of the rotational speed and vibration level of the two-phase stepping motor driven by using the proposed apparatus. As is clear from the figure, the vibration level is greatly suppressed in the speed region of 1 kHz or more except for the low speed region, and it has been proved that a great effect of low vibration can be obtained.

  The driving of the stepping motor device according to the present invention is not limited to the above-described embodiment, and the type and output format of the encoder are not limited, and may be a form external to the stepping motor.

  The motor abnormality detection unit is configured to count an encoder pulse or a pulse obtained by multiplying or dividing the pulse in one cycle of an input pulse, compare the count value with a reference value, and output the comparison result as a rotation unevenness detection signal. As long as it is, any circuit configuration may be used.

  As for the motor vibration suppression unit, when the rotation unevenness detection signal indicates an abnormality in the rotation unevenness of the stepping motor, any circuit can be used as long as the phase of the input pulse is adjusted to suppress the rotation unevenness. You may use the thing of a structure. In particular, when the rotation of the stepping motor is delayed in phase compared to the input pulse, the phase of the input pulse is adjusted to advance or the degree of phase adjustment is adjusted according to the degree of rotation unevenness of the stepping motor. You may take the form of variable adjustment.

It is a figure for demonstrating embodiment of this invention, Comprising: It is a block diagram of a stepping motor drive device. It is a circuit diagram of the motor vibration suppression part of the same apparatus. It is a timing chart which shows the various signal waveforms of the motor abnormality detection part of the device. It is a timing chart which shows the various signal waveforms of the motor vibration control part of the device. It is an experimental result at the time of driving a 5-phase stepping motor, Comprising: It is a graph which shows the characteristic of the rotation speed and vibration level of the motor. It is an experimental result at the time of driving a two-phase stepping motor, Comprising: It is a graph which shows the characteristic of the rotation speed and vibration level of the motor.

Explanation of symbols

A Stepping motor drive device 10 Input terminal 20 Motor abnormality detection unit 30 Motor vibration suppression unit 40 Power supply unit B Stepping motor a Input pulse b Encoder pulse

Claims (3)

An input terminal that receives an input pulse that is an operation command of the stepping motor and an encoder pulse that indicates the rotation amount of the stepping motor, and counts the encoder pulse or a multiplied or divided pulse in one cycle of the input pulse. The motor abnormality detection unit that compares the count value with the reference value and outputs the comparison result as a rotation unevenness detection signal, and the rotation unevenness detection signal indicates that the rotation of the stepping motor is phased in comparison with the input pulse and rotation unevenness A motor vibration suppression unit that delays the phase of the input pulse to suppress the rotation unevenness, and each of driving the stepping motor based on the input pulse derived from the motor vibration suppression unit. A stepping motor drive device comprising: a power supply unit for generating a phase current; An input terminal that receives an input pulse that is an operation command of the stepping motor and an encoder pulse that indicates the amount of rotation of the stepping motor, and counts the encoder pulse or a multiplied or divided pulse in one cycle of the input pulse. The motor abnormality detection unit that compares the count value with the reference value and outputs the comparison result as a rotation unevenness detection signal, and the rotation unevenness detection signal causes the rotation of the stepping motor to be delayed in phase compared to the input pulse. A motor vibration suppression unit that advances the phase of the input pulse to suppress the rotation unevenness when the unevenness is indicated, and a stepping motor that is driven based on the input pulse derived from the motor vibration suppression unit A stepping motor drive comprising: a power supply unit for generating a current of each phase Location. An input terminal that receives an input pulse that is an operation command of the stepping motor and an encoder pulse that indicates the rotation amount of the stepping motor, and counts the encoder pulse or a multiplied or divided pulse in one cycle of the input pulse. A motor abnormality detection unit that compares the count value with a reference value and outputs the comparison result as a rotation unevenness detection signal; and when the rotation unevenness detection signal indicates an abnormality in rotation unevenness of the stepping motor, the phase of the input pulse A motor vibration suppression unit that adjusts the rotation unevenness and a power supply unit that generates each phase current for driving the stepping motor based on the input pulse derived from the motor vibration suppression unit, The motor vibration suppression unit adjusts the phase of the input pulse, and adjusts the phase of the input pulse and the phase. Stepping motor driving device, characterized in that it is configured with a selector for selecting and outputting in response a and the both signals have the input pulse whose phase is adjusted is inputted to the rotation unevenness detection signal by.

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