JP2009017670A - Controller for stepping motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a controller for stepping motor that improves accuracy in origin-position alignment of a stepping motor. <P>SOLUTION: The controller for stepping motor 10 is configured, such at after a rotation reference position of a stepping motor 1 is detected by a reference-position detection means 4; a motor driver 2 is made to output a drive current to a specified step in a prescribed excitation pattern so as to stop the motor at a specified step (for example, fifth step) of an excitation pattern that appears first after passing through the rotation reference position; and accordingly, since the stepping motor 1 can be stopped at a prescribed origin position even if load variations, such as temporal changes or temperature changes (for example, phase delays) occur, the stepping motor 1 is allowed to surely stop at the same origin position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stepping motor control device.

  Conventionally, in a feed mechanism using a stepping motor, in order to detect the origin position of the motor without using a position detector, the movable part is abutted against the end of the mechanical operating range (mechanical limit) and stepped out. A technique is known in which the origin position is defined by storing the phase excitation pattern of the position, and the rotation of the stepping motor is stopped at the stored phase excitation pattern at the time of subsequent origin detection (for example, patent Reference 1).

In addition, a technique is known in which the origin is a position further advanced by a specified number of steps from the place where the origin sensor is turned on when the stepping motor rotates in the origin search direction as the origin position of the feed mechanism or the like.
JP-A-5-236800

  However, in the case of the above-mentioned Patent Document 1, when the feed mechanism is brought into contact with the mechanical limit and stepped out, if the motor torque is large like an industrial sewing machine, abnormal noise may be generated or in the worst case. There was a problem that the feed mechanism might break down.

Further, when the stepping motor is driven by the conventional technique using the origin sensor, there is a phase delay relationship between the excitation phase (driving phase) for driving the motor and the load (rotor) that is actually driven. That is, even when the motor is excited with a predetermined excitation pattern, the load (rotor) is usually delayed so as to move a position several steps before that.
The phase delay may be constant at all times. However, since the phase delay varies depending on the time-dependent change of the stepping motor, the use environment temperature, and the like, there is a problem that the origin position is shifted with the change of the phase delay.

Specifically, in the case of a feed mechanism that uses full-step driving of a five-phase stepping motor, there are 10 excitation patterns (for example, 10 patterns of 0 to 9). Then, the motor controller rotates the motor by repeatedly applying the excitation pattern to the motor in order.
Then, for example, the excitation phase (A) of the motor and the increment of the load position (B) are represented as shown in FIGS. 6 (a) and 6 (b), and the excitation is switched in the direction of arrow C. In this case, as shown in FIG. 6A, the load that follows the excitation position with a delay of 3 steps passes through the origin sensor position, and from the excitation position at that time (position “0” in the figure; 0th step). When excitation is advanced and stopped for the specified 5 steps, the position “5” (fifth step) becomes the origin position. On the other hand, as shown in FIG. 6B, a load that follows the excitation position with a delay of 4 steps passes through the origin sensor position, and from the excitation position (position “1” in the figure; first step) at that time. When excitation is advanced and stopped for the prescribed 5 steps, the position “6” (sixth step) becomes the origin position. That is, the origin position is shifted by one step due to the change in the phase delay.
As described above, the conventional technique has a problem that the reproducibility of the origin position cannot be obtained due to the change in the phase delay.

  An object of the present invention is to provide a stepping motor control device that improves the accuracy of alignment of the origin of a stepping motor.

  In order to solve the above problems, the invention described in claim 1 is a stepping motor control device for driving and controlling a stepping motor, wherein the stepping motor is driven by a reference position detecting means for detecting a rotation reference position of the stepping motor. A motor driver that supplies current and a motor control unit that outputs a drive current corresponding to a predetermined excitation pattern to the motor driver. When the stepping motor is stopped at the origin position, the reference position detection means rotates the stepping motor. After the reference position is detected, the motor control unit causes the motor driver to output a drive current until a specified step in a predetermined excitation pattern, thereby stopping the stepping motor at the origin position corresponding to the specified step. To do.

  According to the first aspect of the present invention, the stepping motor control device outputs a driving current to the motor driver until a predetermined step in a predetermined excitation pattern after the reference position detecting means detects the rotation reference position of the stepping motor. Thus, the motor is stopped at the specified step of the excitation pattern that appears first after passing through the rotation reference position, and the stepping motor can be stopped at the predetermined origin position corresponding to the specified step.

  According to a second aspect of the present invention, in the stepping motor control device according to the first aspect, the reference position detecting means detects the rotation reference position of the stepping motor after the reference position detecting means detects the rotation reference position at the time of adjusting the origin position for stopping the stepping motor. The motor control unit memorizes the step at the position where the excitation has been advanced by about half of the total number of steps of the excitation pattern as the specified step corresponding to the origin position, and the motor control unit stores the motor up to the stored specified step. The stepping motor is stopped at the origin position by causing the driver to output a driving current.

  According to the second aspect of the present invention, the same effect as that of the first aspect of the invention can be obtained, and the stepping motor control device can perform the adjustment of the reference position detecting means at the time of adjusting the origin position for stopping the stepping motor. After detecting the rotation reference position of the stepping motor, it is possible to store and set a step at a position where excitation has been advanced by about half of the total number of steps of a predetermined excitation pattern as a specified step corresponding to the origin position. it can.

According to the first aspect of the present invention, the stepping motor control device outputs a driving current to the motor driver until a predetermined step in a predetermined excitation pattern after the reference position detecting means detects the rotation reference position of the stepping motor. By doing so, the motor can be stopped at the specified step of the excitation pattern that appears first after passing through the rotation reference position, and the stepping motor can be stopped at the predetermined origin position according to the specified step. Even if a load fluctuation (for example, phase delay) occurs, the stepping motor can always stop at the same origin position.
Therefore, this stepping motor control device enables high-accuracy origin search, eliminates problems due to motor stop position deviation, and improves the accuracy of stepping motor origin alignment.

According to the second aspect of the present invention, the stepping motor control device has a predetermined excitation pattern after the reference position detecting means detects the rotation reference position of the stepping motor during the adjustment for setting the origin position for stopping the stepping motor. The step at the position where the excitation has been advanced by about half the number of all the steps can be stored and set as the specified step corresponding to the origin position.
Then, the stepping motor control device can stop the stepping motor at the origin position by causing the motor driver to output a drive current up to the stored specified step.

  Here, the number of steps that is about half of the total number of steps of the predetermined excitation pattern is, for example, when the total number of steps is “10”, half the number of steps “5” or around “5”. The number of steps is about half of “4” and “6”. When the total number of steps is an even number such as “10”, the half number of steps is determined as “5”. However, depending on the arrangement of the reference position detection means and the rotation reference position, about half “4” and “ The step number of “6” may be more preferable as the specified step. In addition, when the total number of steps is an odd number, it is not possible to set exactly half the number of steps. The number of steps is about half of the number.

Hereinafter, an embodiment of a stepping motor control apparatus according to the present invention will be described with reference to the drawings.
In the present embodiment, a stepping motor control device that performs control for full-step driving of a 5-phase stepping motor having a resolution of 0.72 ° will be described as an example.
The scope of the invention is not limited to the illustrated example.

  As shown in FIG. 1, the stepping motor control device 10 outputs a stepping motor 1, a motor driver 2 that supplies a driving current to the stepping motor 1, and a driving current corresponding to a predetermined excitation pattern to the motor driver 2. And a reference position detecting means 4 for detecting the rotation reference position of the stepping motor 1, and the like.

  For example, when the stepping motor 1 is a five-phase stepping motor and is a five-phase HB motor, the stepping motor 1 has a configuration including 10 coils and 50 teeth. Then, in one step, it is rotated 0.72 °, and in 10 steps, the rotor (load) is moved by one tooth.

  The motor driver 2 includes, for example, an excitation circuit 2a that determines the excitation order and a drive circuit 2b that controls the power supplied to the motor.

The motor control unit 3 includes, for example, a CPU that performs various arithmetic processes, a RAM that is used as a work area of the CPU, and a ROM that stores various control programs executed by the CPU, various data, and the like. ing.
The motor control unit 3 outputs a drive current corresponding to the excitation pattern to the motor driver 2 by, for example, outputting a command pulse signal corresponding to a predetermined excitation pattern stored in the ROM to the motor driver 2. Then, the drive current is supplied to the stepping motor 1 so that the stepping motor 1 is controlled to be driven.
The excitation pattern is composed of a plurality of steps, and in the case of full-step driving of a five-phase stepping motor, the predetermined excitation pattern is composed of 10 steps (for example, 10 steps from 0 to 9). The stepping motor 1 can be driven to rotate by the motor driver 2 sequentially supplying a driving current corresponding to each step of the excitation pattern to the stepping motor 1 by the control process of the motor control unit 3.
In addition, the motor control unit 3 executes control related to adjustment processing for setting the origin position for stopping the stepping motor 1 and control related to processing for stopping the stepping motor 1 at the set origin position.

  The reference position detection means 4 is an origin sensor that detects, for example, a rotation reference position applied to the rotor (load) of the stepping motor 1, and when the rotation reference position is detected, a detection signal is sent to the motor control unit. 3 is output.

  When the origin position adjustment process for stopping the stepping motor 1 is performed, the motor control unit 3 of the stepping motor control device 10 performs predetermined excitation after the reference position detection unit 4 detects the rotation reference position of the stepping motor 1. A step corresponding to the origin position is a step at a position where excitation is advanced by about half the number of steps of the pattern (10 steps in this embodiment) (for example, 4 steps and 5 steps in this embodiment). As a step, control stored in the RAM of the motor control unit 3 is executed.

  Further, when performing the origin return operation for stopping the stepping motor 1 at the origin position, the motor control unit 3 of the stepping motor control device 10 detects the rotation reference position of the stepping motor 4 by the reference position detection means 4 and then performs the motor The control unit 3 stops the stepping motor 1 at the origin position corresponding to the specified step by causing the motor driver 2 to output the drive current until the specified step stored in the RAM, which is the specified step in the predetermined excitation pattern. The control to be executed is executed.

  Next, an adjustment process for setting an origin position for stopping the stepping motor 1 by the stepping motor control apparatus 10 according to the present embodiment will be described based on a flowchart shown in FIG.

  First, when an origin search signal for setting an origin position for stopping the stepping motor 1 is input to the motor control unit 3, the motor control unit 3 accompanies that the reference position detection unit 4 has detected the rotation reference position. It is determined whether or not a detection signal has been input (step S101).

When the motor control unit 3 determines that the reference position detection signal has been input (step S101; Yes), the motor control unit 3 is the timing at which the reference position detection signal is input in the excitation pattern consisting of 10 steps of 0 to 9. From this step, 5 steps, which is about half of the total number of steps, and the step at the position where excitation is advanced are acquired (step S102).
Specifically, as shown in FIG. 3A, when the load follows the excitation position with a delay of 3 steps, the reference position detection unit 4 performs the seventh step corresponding to the rotation reference position. When detected, since the excitation phase has reached the 0th step, the motor control unit 3 acquires the 5th step at the position where the excitation is advanced by 5 steps from the 0th step.

Then, the motor control unit 3 stores and sets the acquired fifth step in the RAM as a defining step corresponding to the origin position (step S103).
If there is an inconvenience or problem in the acquired fifth step, a more appropriate specified step is stored by acquiring the step at the position where the four-step excitation or the six-step excitation is advanced, which is about half of the total number of steps. And store it.
In this way, the motor control unit 3 of the stepping motor control device 10 sets a specified step relating to the origin position where the stepping motor 1 is stopped. Then, the origin position is adjusted according to the specified step.

  Next, the origin return operation processing for stopping the stepping motor 1 at the origin position by the stepping motor control device 10 in the present embodiment will be described based on the flowchart shown in FIG.

  First, when a motor stop signal for stopping the stepping motor 1 is input to the motor control unit 3, the motor control unit 3 receives a detection signal associated with the reference position detection unit 4 detecting the rotation reference position. It is determined whether or not (step S201).

  When the motor control unit 3 determines that the reference position detection signal has been input (step S201; Yes), the motor control unit 3 causes the motor driver 2 to output a drive current until the specified step stored in the RAM (step S202). .

When the excitation phase of the motor reaches the specified step (Step S203; Yes), the stepping motor 1 stops at the origin position corresponding to the specified step (Step S204).
Specifically, as shown in FIG. 3 (b), when the load follows the excitation position with a phase delay of 4 steps, unlike the phase delay of 3 steps when the origin position is set. Even so, the motor stops at the fifth step, which is the first defined step that appears after passing the rotation reference position, and even if the phase delay of the stepping motor 1 changes, the stop position of the stepping motor 1 is stable. Will be.

  Here, the reason why the prescribed step corresponding to the origin position is set to a step at a position where excitation is advanced by about half the number of steps of the excitation pattern is explained.

As shown in FIG. 5A, when the load follows the excitation position with a delay of 3 steps, the 0th step when the reference position detection means 4 detects the seventh step corresponding to the rotation reference position. It is assumed that the first step at the position where excitation has been advanced by one step from the step is set as a specified step corresponding to the origin position.
Then, during the origin return operation in which the stepping motor 1 is stopped at the origin position, as shown in FIG. 5B, if the load follows the excitation position with a delay of 5 steps, the rotation reference position passes. If the motor is stopped in the first step, which is the first defined step that appears later, the stop position is shifted by one cycle of the excitation pattern, that is, the position corresponding to the first step shifted by 10 steps. The problem will arise.

On the other hand, according to the present invention, according to the step of the position where the excitation is advanced by 5 steps, which is about half the total number of steps of the excitation pattern, as the specified step corresponding to the origin position, Regardless of the degree of phase delay, the motor stop position can be stopped at a predetermined origin position without being shifted by one cycle of the excitation pattern. That is, the prescribed steps are not too many and not too small with respect to the total number of steps of the excitation pattern, and are preferably about half of the middle.
It should be noted that half the number of steps in the excitation pattern is not the specified step, but the half number of steps, which is almost in the middle, is the specified step because the total number of steps is an even number such as “10”. In this case, half the number of steps is determined to be “5”, but depending on the position of the reference position detecting means 4 and the rotation reference position of the stepping motor 1, about half of the “4” and “6” steps are set. This is because the number may be more suitable as the prescribed step, and when the total number of steps is an odd number, it is not possible to determine exactly half the number of steps.

As described above, the stepping motor control device 10 according to the present invention enables the motor driver to perform a predetermined step (fifth step) in a predetermined excitation pattern after the reference position detection unit 4 detects the rotation reference position of the stepping motor 1. By outputting the drive current to No. 2, the motor is stopped at the specified step (fifth step) of the excitation pattern that appears first after passing through the rotation reference position, and the stepping motor 1 can be stopped at the predetermined origin position. Even if load fluctuations (eg, phase lag) such as changes over time or temperature changes occur, the stepping motor 1 always stops at the same origin position, enabling high-precision origin search and stopping the motor. Problems due to misalignment can be eliminated. That is, it becomes possible to improve the accuracy of the origin position alignment of the stepping motor 1.
In particular, by setting the number of steps of excitation after passing the rotation reference position to about half of the number of excitation patterns, even if load fluctuations such as changes over time or temperature changes occur, the specified steps in the excitation pattern are erroneously recognized. Therefore, the motor stop position is not shifted by one cycle of the excitation pattern, and the origin search can be performed with higher accuracy.

  In the above embodiment, the case of full-step driving of a 5-phase stepping motor with a resolution of 0.72 ° has been described as an example. However, the present invention is not limited to this, for example, half-step driving. Other stepping such as (excitation pattern consisting of 20 steps in total), full-step drive of 1.8 ° 2-phase stepping motor (excitation pattern of all 4 steps), half-step drive (excitation pattern of all 8 steps), etc. You may apply to the drive control of a motor.

  In addition, it is needless to say that other specific detailed structures can be appropriately changed.

It is a block diagram which shows the principal part structure of the stepping motor control apparatus which concerns on this invention. It is a flowchart which shows the adjustment process which sets the origin position which stops a stepping motor by a stepping motor control apparatus. It is explanatory drawing which shows the correlation of the excitation phase of a stepping motor, and the position of a load, The adjustment process (a) of the origin position which made the adjustment step number "5" in the case of 3 steps of phase delays, and the phase of 4 steps The origin return operation process (b) at the time of delay is shown. It is a flowchart which shows the origin return operation | movement process which stops a stepping motor by an origin position by a stepping motor control apparatus. It is explanatory drawing which shows the correlation of the excitation phase of a stepping motor, and the position of a load, The adjustment process (a) of the origin position which made the number of adjustment steps "1", and the stop position shifted | deviated by 1 cycle of the excitation pattern (B) is shown. It is explanatory drawing which shows the correlation of the excitation phase of a stepping motor, and the position of a load, (a) in the case of the 3-step phase delay in the conventional origin return operation processing, and the 4-step phase delay in the conventional origin return operation processing Case (b) is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stepping motor 2 Motor driver 3 Motor control part 4 Reference position detection means 10 Stepping motor control apparatus

Claims (2)

A stepping motor control device for driving and controlling a stepping motor,
A reference position detecting means for detecting a rotation reference position of the stepping motor;
A motor driver for supplying a driving current to the stepping motor;
A motor control unit for causing the motor driver to output a drive current according to a predetermined excitation pattern,
When stopping the stepping motor at the origin position,
After the rotation reference position of the stepping motor is detected by the reference position detection means, the motor control unit causes the motor driver to output a drive current until a predetermined step in a predetermined excitation pattern, thereby causing the stepping motor to A stepping motor control device that stops at an origin position corresponding to the prescribed step. At the time of adjusting the origin position for stopping the stepping motor, the reference position detection means detects the rotation reference position of the stepping motor, and then proceeds with excitation by about half of the number of steps of the predetermined excitation pattern. The step of the position is stored by the motor control unit as a specified step corresponding to the origin position,
2. The stepping motor control device according to claim 1, wherein the motor control unit stops the stepping motor at an origin position by causing the motor driver to output a driving current until the stored specified step. 3.

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