JP2005073441A - Stepping motor driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the vibration of a rotor when held, to suppress the occurrence of noise, and to shorten the rising time of a motor, that is, to achieve the stable and quick rising of the motor. <P>SOLUTION: This stepping motor driving method is for driving the motor by exciting each phase according to a driving signal output from a motor driving signal generating source including a motor driving IC. In a motor-starting control in which the motor starts rotation from a pull-in range of low-speed rotation in which self-starting is possible and the revolutions are gradually increased to rotate the motor in the pull-out range of targeted high-speed rotation, an excited state and a non-excited state are repeated initially for a fixed period of time, when the motor standing by in the non-excited state is excited upon the start of the driving. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a stepping motor that excites and drives each phase in accordance with a drive signal output from a motor drive signal generation source such as a motor drive IC, and more particularly to a sequence of initial input pulses when the motor is started from a non-excitation standby state. Is.

  In stepping motors that are waiting in a non-excited state, the pole position of the rotor and the position of the phase that is first excited at start-up are often shifted. Therefore, in the conventional stepping motor start-up control, when starting up a motor that is waiting in a non-excited state, in order to determine the initial position of the rotor, it is called the hold control at the beginning of the start-up. Control is performed to continuously excite any phase for a certain period of time. If the start-up of the motor is started without determining the initial position of the rotor, the rotation direction of the rotor is not determined, and the rotor cannot follow the rotation, resulting in turbulence. Therefore, by performing this hold control, the initial position of the rotor is determined, and it is possible to prevent the rotor from causing turbulence during start-up and to stably start up the stepping motor without causing step-out.

  However, when the hold control is performed, the distance by which the rotor is rotated from an arbitrary position to the initial position may be longer than the moving distance of one step during normal rotation. Therefore, the vibration of the rotor that occurs during the hold period becomes relatively large, and there may be a case where a loud noise (hereinafter referred to as noise) is generated due to a gear backlash or the like when driving transmission by a gear. Also, a relatively long time is required until the vibration of the rotor is settled. Therefore, if the start-up of the motor is started after the vibration of the rotor is settled in order to realize a stable start-up of the motor, the start-up time of the motor becomes long.

  The present invention has been made in view of such a situation, and makes it possible to reduce the vibration of the rotor at the time of holding, suppress the generation of noise, and shorten the start-up time of the motor. That is, an object is to realize a stable and fast start-up of the motor.

  In order to achieve the above object, a driving method according to claim 1 is a stepping motor driving method in which excitation is performed by exciting each phase in accordance with a driving signal output from a motor driving signal generating source such as a motor driving IC. In the motor start-up control that starts rotation from the low-speed rotation pull-in area where the motor can start automatically and gradually increases the rotation speed in the target high-speed rotation pull-out area, it stands by in the non-excited state In the case where excitation is performed simultaneously with the start of driving of the motor being operated, the excitation state / non-excitation state is first repeated for a certain period.

  The driving method according to claim 2 is characterized in that, in the driving method according to claim 1, the ratio of excitation time / non-excitation time is made constant.

  The drive method according to claim 3 is characterized in that, in the drive method according to claim 1, the ratio of excitation time / non-excitation time is changed.

  The drive method according to claim 4 is the drive method according to any one of claims 1 to 3, wherein the constant current set value of the motor drive current is set to the drive current during steady rotation while the excitation state / non-excitation state is repeated. And switching to a different value.

  According to the stepping motor driving method of the present invention, by repeating the excitation state / non-excitation state of the motor at the time of holding, the vibration of the rotor at the time of holding can be suppressed, and noise can be reduced. Further, by making the motor drive current value at the time of holding lower than the drive current value at the time of steady rotation, it is possible to further reduce noise.

  In addition, this stepping motor driving method can be applied to all devices using a stepping motor such as a laser beam printer, an ink jet printer, and a camera.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
When starting a stepping motor that drives by exciting each phase according to a drive signal output from a motor drive signal generation source such as a motor drive IC, a pull-out with a high rotational speed is required for steady-state driving. If it is in the region, it is impossible to start the motor at that rotational speed, so the rotation starts from the pull-in region where the self-starting is possible and the rotational speed is low, and gradually reaches the target rotational speed as shown in FIG. Slow-up control is performed to increase the rotation speed. At this time, when the motor is on standby in a non-excited state, and excitation is started at the same time as the start-up of the motor and driving is started, the position of the waiting rotor 4 is not fixed as shown in FIG. Since it is at an arbitrary position, it is necessary to first carry out excitation for determining the position of the rotor 4 first. This excitation continues to excite a phase as shown in FIG. 2, thereby attracting and stabilizing the rotor 4 to the excitation phase as shown in FIG. 4 (b), and determining the position of the rotor 4 as shown in FIG. 4 (d). Called hold by control. If driving of the motor is started without performing this hold control, the rotation direction of the rotor 4 becomes unstable and the rotor 4 cannot follow the drive signal, causing turbulence and escaping. May cause a tone.

  As described above, the hold control is an important control for driving the stepping motor. However, the hold causes the rotor 4 to rotate from an arbitrary position in the non-excited state to the initial excitation phase, and thus causes vibration 8 at the position of the excitation phase as shown in FIG. The moving distance of the rotor 4 at that time may be longer than the moving distance of one step during normal rotation. Therefore, in such a case, the vibration 8 of the rotor 4 generated at the time of holding is proportional to the moving distance of the rotor 4 and thus becomes relatively large, and noise is generated due to a gear backlash or the like for driving transmission. End up.

  Therefore, the phase excitation state / non-excitation state is repeated as shown in FIG. Here, if the control is performed so that the ratio of the excitation time / non-excitation time is constant, for example, 1: 1, the control can be realized without complicating the control. As a result, the effective value of the drive current 6 flowing through the motor is reduced as shown in FIG. Therefore, since the attractive force to the phase of the rotor 4 is proportional to the drive current, the pulling speed to the phase of the rotor 4 can be suppressed. Therefore, even when the moving distance to the initial excitation phase is long, the vibration 8 of the rotor 4 at the time of holding can be suppressed small, and since the vibration 8 is small, the time until the vibration converges is shortened. (FIG. 6) Accordingly, it is possible to suppress the generation of noise and realize a fast motor start-up.

(Second embodiment)
When starting a stepping motor that drives by exciting each phase according to a drive signal output from a motor drive signal generation source such as a motor drive IC, a pull-out with a high rotational speed is required for steady-state driving. Slow-up control is performed when in the area. At this time, if the motor is waiting in a non-excited state, the excitation for determining the position of the rotor 4 must always be performed first. If driving of the motor is started without performing this hold control, the rotation direction of the rotor 4 becomes unstable and the rotor 4 cannot follow the drive signal, causing turbulence and escaping. May cause a tone.

  As described above, the hold control is an important control for driving the stepping motor. However, the vibration 8 of the rotor 4 generated at the time of holding becomes relatively large, and noise is generated due to a gear backlash or the like for transmitting drive.

  Therefore, the excitation state / non-excitation state of the phase is repeated without continuing to excite the phase during this hold. Here, as shown in FIG. 7, control is performed so that the ratio of excitation time / non-excitation time is changed, for example, the excitation time is gradually increased. As a result, the effective value of the drive current 6 flowing through the motor decreases, the pulling speed of the rotor 4 into the phase can be suppressed, and the effective current 6 increases by gradually increasing the excitation time. After slowly pulling 4 in, positioning can be performed with a strong force. Therefore, even when the moving distance to the initial excitation phase is long, the vibration 8 of the rotor 4 at the time of holding can be suppressed small, and the subsequent vibration 8 can be converged quickly. Therefore, it is possible to suppress the generation of noise and realize a fast motor start-up.

(Third embodiment)
When starting a stepping motor that drives by exciting each phase according to a drive signal output from a motor drive signal generation source such as a motor drive IC, a pull-out with a high rotational speed is required for steady-state driving. Slow-up control is performed when in the area. At this time, if the motor is waiting in a non-excited state, the excitation for determining the position of the rotor 4 must always be performed first. If driving of the motor is started without performing this hold control, the rotation direction of the rotor 4 becomes unstable and the rotor 4 cannot follow the drive signal, causing turbulence and escaping. May cause a tone.

  As described above, the hold control is an important control for driving the stepping motor. However, the vibration 8 of the rotor 4 generated at the time of holding becomes relatively large, and noise is generated due to a gear backlash or the like for transmitting drive.

  Therefore, the excitation state / non-excitation state of the phase is repeated without continuing to excite the phase during this hold. Here, the ratio of excitation time / non-excitation time is fixed or changed. As a result, the effective value of the drive current 6 flowing through the motor decreases. Furthermore, the effective value of the drive current 6 can be further reduced by lowering the constant current set value of the motor drive current 6 below the drive current 6 during steady rotation. Therefore, the drawing speed to the phase of the rotor 4 can be further suppressed. Therefore, even when the moving distance to the initial excitation phase is long, the vibration 8 of the rotor 4 at the time of holding can be further reduced, and since the vibration 8 becomes small, the time until the vibration 8 converges is also shortened. Therefore, it is possible to suppress the generation of noise and realize a fast motor start-up.

The sequence which shows the hold control in 1st embodiment of this invention. The sequence which shows the hold control in a prior art example. The relationship between the time of slow-up and the motor speed. The schematic diagram which shows the behavior of the rotor at the time of a hold | maintenance. Drive current waveform during hold. The relationship figure of the amplitude of vibration at the time of holding, and convergence time. The sequence which shows the hold control in 2nd embodiment of this invention.

Explanation of symbols

1 A phase sequence 2 B phase sequence 3 Slow up 4 Rotor 5 Stator 6 Current waveform 7 ON / OFF signal 8 Vibration waveform

Claims (4)

  A stepping motor driving method in which each phase is excited and driven in accordance with a drive signal output from a motor drive signal generation source such as a motor drive IC. In motor start-up control that starts and gradually increases the rotation speed and rotates in the target high-speed rotation pullout region, if excitation is performed at the same time as the start of driving to a motor that is waiting in a non-excitation state, the excitation state is the first / A stepping motor drive method characterized by repeating the non-excitation state for a certain period.   2. The driving method according to claim 1, wherein a ratio of excitation time / non-excitation time is made constant.   2. The stepping motor driving method according to claim 1, wherein a ratio of excitation time / non-excitation time is changed.   4. The stepping motor according to claim 1, wherein the constant current set value of the motor drive current is switched to a value different from the drive current during steady rotation while the excitation state / non-excitation state is repeated. Driving method.

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