JP2011067013A - Motor control method for stepping motor, control device for the stepping motor, and stepping motor system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for a stepping motor that allows a stepping motor to rotate from a current coordinate to a target coordinate in a short period of time, even if the target coordinate is changed little at a time. <P>SOLUTION: A coordinate prior to the start of rotation of a stepping motor and a first number of pulses required for rotating the stepping motor from the coordinate before the start of rotation to a target coordinate are acquired; the total number of pulses outputted from the start of rotation of the stepping motor is acquired so as to set it as a second number of pulses; the second number of pulses is subtracted from the first number of pulses so as to acquire a third number of pulses required for making the stepping motor reach the target coordinate; then, a fourth number of pulses required by the time the stepping motor is stopped from the current speed is acquired; and it is determined whether to accelerate or decelerate the stepping motor from the current speed or to maintain the maximum speed, in order to rotate the stepping motor from the current coordinate to the target coordinate, on the basis of the third number of pulses and the fourth number of pulses. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a stepping motor control method, a stepping motor control device, and a stepping motor system.

  When using a motor to rotate a rotating body to a target rotation angle, the following methods are conceivable.

(When using a servo motor)
The encoder detects the rotation angle of the motor shaft, feeds back the detected rotation angle to the controller and driver, adjusts the motor rotation speed while checking the feedback rotation angle, and rotates the motor shaft to the target rotation angle. Let

(When using a stepping motor)
A pulse for rotating the motor shaft to the target rotation angle given as the target coordinates is generated to drive the driver, and the motor shaft is rotated to the target rotation angle.

  The servo motor and stepping motor control methods are described in, for example, Patent Documents 1 and 2.

  However, the servo motor feeds back the rotation angle detected by the encoder to the controller or driver. For this reason, feedback must always be confirmed, and many calculations are required for fine alignment.

  On the other hand, the stepping motor is configured to rotate by a certain angle (step angle) with one pulse. For this reason, open-loop control can be performed, and high-speed alignment is possible when open-loop control is performed.

JP 2004-282972 A JP 2007-185052 A

  However, once the stepping motor indicates the target coordinate (target rotation angle), it cannot issue a new target coordinate until the rotation to the target coordinate is completed. This is because the CPU issues not only a target coordinate but also an acceleration instruction and a deceleration instruction. In other words, after issuing the target coordinates, the CPU issues and calculates in advance the timing for ending acceleration and the timing for starting deceleration so that the stepping motor reaches the target coordinates. Since such a calculation is performed by the CPU, the CPU cannot perform a calculation for a new target coordinate in advance unless the rotation to the target coordinate is once ended.

  For this reason, when the target coordinates are changed in small increments, extra acceleration and deceleration times are required, and extra time is required for alignment.

  The present invention has been made in view of the above circumstances. A stepping motor control method and a stepping motor control capable of rotating a stepping motor to a target coordinate in a short time even if the target coordinate is changed in small increments. An apparatus and a stepping motor system are provided.

  In order to solve the above-mentioned problem, a stepping motor control method according to a first aspect of the present invention is a stepping motor control method for rotating a stepping motor to a target coordinate according to an output pulse, wherein the stepping motor is rotated. The coordinates before the start are acquired, the first number of pulses necessary for rotating the stepping motor from the coordinates before the start of rotation to the target coordinates is acquired, and the cumulative number of pulses output from the start of the rotation of the stepping motor To obtain the second pulse number, and subtract the second pulse number from the first pulse number to obtain the third pulse number necessary to reach the target coordinate, and the stepping A fourth pulse number required until the motor stops from the current speed is acquired, and the third pulse number and the fourth pulse are acquired. Based on, the stepping motor to rotate toward the target coordinates, or to accelerate the stepping motor from the current speed, or decelerating, or the determining to maintain the maximum speed.

  A stepping motor control device according to a second aspect of the present invention is a stepping motor control device that rotates a stepping motor to a target coordinate according to an output pulse, and acquires coordinates before the rotation of the stepping motor is started. Means for obtaining a first pulse number required to reach the target coordinate from the coordinates before the start of rotation, and means for obtaining a second pulse number that is the cumulative number of pulses output after the start of rotation. And means for obtaining the third number of pulses required to reach the target coordinates by subtracting the second number of pulses from the first number of pulses, and necessary for stopping from the current speed. A step of obtaining the fourth pulse number, and directing the stepping motor to the target coordinate based on the third pulse number and the fourth pulse number. Provided in order to rotate, or to accelerate the stepping motor from the current speed, or slowing, or means for determining to maintain the maximum speed, the.

  A stepping motor system according to a third aspect of the present invention is capable of issuing a stepping motor and a target coordinate and issuing a new target coordinate different from the target coordinate after issuing the target coordinate. An apparatus, a pulse generator that receives the target coordinates and the new target coordinates, and generates a driving pulse that rotates the stepping motor; and a driver that receives the driving pulse and rotates the stepping motor, A pulse generator that receives the target coordinates and the new target coordinates and issues an acceleration instruction and a deceleration instruction, a speed counter that receives the acceleration instructions and a deceleration instruction and generates speed data, and the coordinates of the stepping motor And the cumulative number of pulses output from the start of rotation A coordinate counter that generates a drive pulse that rotates the stepping motor in response to the speed data, and receives the acceleration instruction and the deceleration instruction and accelerates the stepping motor. Deceleration that adds and accumulates every time a drive pulse is generated and subtracts the drive pulse every time the drive pulse is generated while decelerating the stepping motor from the accumulated number of drive pulses A time coordinate change amount counter, wherein the controller obtains coordinates before starting the rotation of the stepping motor from the coordinate counter, and rotates the stepping motor from the coordinates before starting the rotation to the target coordinates. Accumulated pulses output from the start of rotation of the stepping motor after obtaining the required number of first pulses Is obtained from the coordinate counter as the second pulse number, and the third pulse number necessary to reach the target coordinate is obtained by subtracting the second pulse number from the first pulse number. Then, the fourth pulse number required until the stepping motor stops from the current speed is acquired from the deceleration coordinate change amount counter, and based on the third pulse number and the fourth pulse number, In order to rotate the stepping motor toward the target coordinates, it is determined whether to accelerate, decelerate, or maintain the maximum speed from the current speed.

  According to the present invention, it is possible to provide a stepping motor control method, a stepping motor control device, and a stepping motor system that can rotate the stepping motor to the target coordinates in a short time even if the target coordinates are changed in small increments.

The block diagram which shows an example of the stepping motor system which can apply the control method of the stepping motor which concerns on one Embodiment of this invention Block diagram showing an example of the pulse generator 3 shown in FIG. The figure which shows the example of speed pattern control by the control method of the stepping motor which concerns on one Embodiment of this invention The figure which shows the example of speed pattern control by the control method of the stepping motor which concerns on one Embodiment of this invention The figure which shows the example of speed pattern control by the control method of the stepping motor which concerns on one Embodiment of this invention The figure which shows the example of speed pattern control by the control method of the stepping motor which concerns on a reference example

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that common parts are denoted by common reference numerals throughout the drawings.

  In this description, the term “coordinate” means “absolute coordinate” when simply written as “coordinate”, and means “relative coordinate” when specially mentioned as “relative coordinate”.

(Stepping motor system)
FIG. 1 is a block diagram showing an example of a stepping motor system to which a stepping motor control method according to an embodiment of the present invention can be applied.

  As shown in FIG. 1, the stepping motor system issues a target coordinate with the stepping motor 1 and an arithmetic device (CPU that can issue a new target coordinate different from the target coordinate after issuing the target coordinate. ) 2, a target coordinate and a new target coordinate, and a pulse generator 3 that generates a driving pulse that rotates the stepping motor 1, and a driver 4 that receives the driving pulse and rotates the stepping motor 1. . For example, the driver 4 rotates the stepping motor 1 by a certain angle (step angle) every time a driving pulse is given.

  In the stepping motor system configured as described above, in the present embodiment, the pulse generator 3 is configured as follows.

(Pulse generator)
FIG. 2 is a block diagram illustrating an example of the pulse generator 3.

  As shown in FIG. 2, the pulse generator 3 according to an example includes a controller 31, a speed counter 32, a coordinate counter 33, a deceleration coordinate change amount counter 34, a rotation direction signal 35, an acceleration / deceleration instruction signal 36, and a speed instruction value 37. , Including a drive pulse 38.

  The controller 31 receives the target coordinate and the new target coordinate from the arithmetic device 2 and issues an acceleration instruction, a deceleration instruction, or a speed maintenance instruction as the acceleration / deceleration instruction signal 36.

  The speed counter 32 receives the acceleration / deceleration instruction signal 36 and generates a speed instruction value 37.

  The coordinate counter 33 includes an absolute coordinate register 61, a rotation start coordinate register 62, and a relative coordinate register 63.

  The absolute coordinate register 61 is, for example, 14 bits long.

  The rotation start coordinate register 62 is, for example, 14 bits long.

  The relative coordinate register 63 includes an upper part 63a and a lower part 63b.

  The relative coordinate register 63 is, for example, 36 bits long, the upper part 63a is, for example, 14 bits, and the lower part 63b is, for example, 22 bits.

Before the stepping motor 1 is stopped and starts a new rotation, the relative coordinate register 63 is reset to zero for both the upper part and the lower part.
Further, the value of the absolute coordinate register 61 that is the current coordinate being stopped is stored in the rotation start coordinate register 62.

  The coordinate counter 33 adds the speed instruction value 37 to the current value of the relative coordinate register 63 and updates the relative coordinate register 63 in synchronization with a clock (not shown). The least significant bit of the upper part 63a is used as a drive pulse 38 for rotating the stepping motor 1.

  When the value of the relative coordinate register upper part 63a changes, the absolute coordinate register 61 is updated to keep the latest state.

  Specifically, the absolute coordinate update value is obtained by adding or subtracting the value of the relative coordinate register upper part 63a to the value of the rotation start coordinate register 62 in accordance with the rotation direction of the stepping motor 1.

  The coordinate change counter 34 at the time of deceleration receives the acceleration instruction and the deceleration instruction from the controller 31 and accumulates the drive pulse every time the drive pulse is generated while the stepping motor 1 is accelerated. Further, the deceleration coordinate change amount counter 34 subtracts the driving pulse from the accumulated number of driving pulses every time the driving pulse is generated while the stepping motor 1 is decelerated. The number of drive pulses added and accumulated during acceleration and subtracted during deceleration is equal to the number of pulses required until the stepping motor 1 stops from the current speed.

  In trapezoidal driving, the number of pulses (acceleration pulse) Pacc required to reach the maximum speed Vpeak from the zero speed is the same as the number of pulses (deceleration pulse number) Pdec required to reach the zero speed from the maximum speed Vpeak. It can be assumed that there is. In this case, if the number of pulses is subtracted from the acceleration pulse number Pacc one by one each time a drive pulse is output during deceleration, the remaining number of pulses required until the stepping motor 1 stops is obtained. I can know.

  The coordinate change counter 34 at the time of deceleration can be configured to obtain the value by integrating the speed instruction value 37.

  Specifically, the bit length of the coordinate change counter 34 during deceleration is made equal to the relative coordinate register 63. The deceleration coordinate change amount counter 34 includes an upper part and a lower part, and the bit length of the upper part is made equal to the bit length of the relative coordinate register upper part 63a.

  Before the stepping motor 1 is stopped and starts a new rotation, the coordinate change counter 34 during deceleration is reset to zero.

  When the acceleration / deceleration instruction signal 36 is an acceleration instruction, the speed instruction value 37 is added to the current value of the deceleration coordinate change amount counter 34 and integrated.

  If the acceleration / deceleration instruction signal 36 is a deceleration instruction, the speed instruction value 37 is subtracted from the current value of the deceleration coordinate change amount counter 34 and integrated.

  When the acceleration / deceleration instruction signal 36 is a speed maintenance instruction, no integration is performed.

  The rotation direction signal 35 instructs the driver 4 on the rotation direction.

  The controller 31 receives the target coordinate (D1) during the stop, and then subtracts the current coordinate (S1) during the stop from the target coordinate (D1) and rotates it to the target coordinate (D1). The number of pulses of 1 (P1) is calculated.

  The controller 31 is rotating the stepping motor 1 by always subtracting the cumulative drive pulse number (second pulse number, P2) output from the start of rotation from the first pulse number (P1) after starting rotation. The third pulse number (P3) necessary for rotating from the current coordinate (C1) to the target coordinate (D1) is always acquired.

  The cumulative drive pulse number (second pulse number, P2) output from the start of rotation is stored in the relative coordinate register upper part 36a.

  By comparing the third pulse number (P3) with the coordinate change amount counter value (P4) during deceleration, the optimum operation of the stepping motor is selected from the three types of acceleration, deceleration and maximum speed maintenance. .

  An example of a specific determination is that if the value obtained by subtracting the deceleration coordinate change counter (P4) from the third pulse number (P3) is greater than 0, the stepping motor 1 decelerates from the current coordinates (C1) during rotation. Even so, since the target coordinate (D1) is not reached, the controller 31 controls the stepping motor to be accelerated or to maintain the maximum speed.

  Further, when the value obtained by subtracting the deceleration coordinate change amount counter (P4) from the third pulse number (P3) is 0 or less, the target coordinate (D1) when the stepping motor 1 decelerates from the rotating current coordinate (C1). ) Is reached or exceeded, the controller 31 controls the stepping motor 1 to decelerate.

  Furthermore, after receiving the new target coordinate (D2) during the rotation, the controller 31 subtracts the coordinate (S1) before the rotation start from the new target coordinate (D2) to the new target coordinate (D2). A fifth pulse number (P5) necessary for rotation is calculated and replaced with the first pulse number (P1). Therefore, the controller 31 can select an optimum operation from the three types of acceleration, deceleration, and maximum speed maintenance to rotate the stepping motor 1 to the new target coordinate (D2) even after receiving the new target coordinate. .

  In the above description, the operation of the stepping motor is selected by comparing the number of pulses, but it is also possible to select the operation by comparing the target coordinates and the estimated stop coordinates.

  The controller 31 receives the target coordinate (D1) during the stop, and then sets the rotation direction signal 35, the acceleration / deceleration instruction signal 36 and others from the target coordinate (D1) and the current coordinate (S1) during the stop. Start operation.

  After starting the rotation, the controller 31 calculates the estimated stop coordinate (S2) using the following equation.

When the stepping motor 1 is rotating forward:
Estimated stop coordinate (S2) = (value of absolute coordinate register 61) + (value of coordinate change counter 34 during deceleration)
When the stepping motor 1 is rotating in reverse:
Estimated stop coordinate (S2) = (value of absolute coordinate register 61) − (value of coordinate change counter 34 during deceleration)
By comparing the target coordinates (D1) and the estimated stop coordinates (S2), the optimum operation of the stepping motor is selected from the three types of acceleration, deceleration, and maximum speed maintenance.

  As an example of the determination, when the rotation direction is positive and the estimated stop coordinate (S2) is smaller than the target coordinate (D1), the target coordinate (D1) even if the stepping motor 1 decelerates from the current coordinate (C1) during rotation. Therefore, the controller 31 controls the stepping motor to accelerate or maintain the maximum speed.

  When the rotation direction is positive and the estimated stop coordinate (S2) is a value greater than or equal to the target coordinate (D1), the stepping motor 1 reaches the target coordinate (D1) when decelerated from the current coordinate (C1) during rotation. Alternatively, the controller 31 controls the stepping motor 1 to decelerate.

  Furthermore, when the controller 31 receives a new target coordinate (D2) during rotation, the controller 31 immediately replaces the target coordinate (D1) with the new target coordinate (D2). Therefore, the controller 31 can select an optimum operation from the three types of acceleration, deceleration, and maximum speed maintenance to rotate the stepping motor 1 to the new target coordinate (D2) even after receiving the new target coordinate. .

  Hereinafter, it demonstrates in detail with a specific control example.

  The pulse generator 3 according to an example can accept a new target coordinate in any case of acceleration, maximum speed, and deceleration. A control example will be described for each of these three cases.

(Control example 1: When new target coordinates are accepted during acceleration)
1.1 When the new target coordinates are not reached even after decelerating In this case, the controller 31 causes the stepping motor 1 to reach the new target coordinates from the coordinates when the new target coordinates are received. Accelerate.

  FIG. 3A shows an example of control when reaching a new target coordinate without reaching the maximum speed after acceleration.

  As shown in FIG. 3A, after receiving a new target coordinate, the controller 31 continues to accelerate the stepping motor 1 and switches to deceleration so as to reach the new target coordinate during the acceleration.

  FIG. 3B shows an example of control when reaching a new target coordinate after reaching the maximum speed Vpeak after acceleration.

  As shown in FIG. 3B, after receiving the new target coordinates, the controller 31 continues the acceleration of the stepping motor 1 until reaching the maximum speed Vpeak, and decelerates from the maximum speed Vpeak to reach the new target coordinates. Switch.

1.2 New target coordinates are reached or decelerated when decelerating In this case, the controller 31 causes the stepping motor 1 to reach the new target coordinates from the coordinates when the new target coordinates are received. To slow down.

  FIG. 3C shows an example of control in a case where the new target coordinates are reached just after decelerating.

  As shown in FIG. 3C, after receiving the new target coordinates, the controller 31 switches the stepping motor 1 to deceleration so as to reach the new target coordinates during the acceleration.

  FIG. 3D and FIG. 3E show control examples when the new target coordinates are exceeded when decelerated.

  After receiving the new target coordinates, the controller 31 switches the stepping motor 1 to deceleration during acceleration. After the stepping motor 1 stops, for example, the controller 31 inverts the rotation direction signal, generates a drive pulse, reversely rotates the stepping motor 1, and reaches the new target coordinates. Accelerate and decelerate (FIG. 3D), or accelerate to the maximum speed Vpeak and then decelerate (FIG. 3E).

(Control example 2: When a new target coordinate is received at the maximum speed)
2.1 When the new target coordinates are not reached even after decelerating In this case, the controller 31 causes the stepping motor 1 to reach the new target coordinates from the coordinates when the new target coordinates are received. Drive at maximum speed.

  As shown in FIG. 4A, after receiving the new target coordinates, the controller 31 continuously operates the stepping motor 1 at the maximum speed Vpeak, and decelerates so as to reach the new target coordinates in the middle of the maximum speed Vpeak. Switch to.

2.2 When the new target coordinates are reached or exceeded when decelerating In this case, the controller 31 causes the stepping motor 1 to reach the new target coordinates from the coordinates when the new target coordinates are received. To slow down.

  FIG. 4B shows an example of control in a case where a new target coordinate is reached when the vehicle is decelerated.

  As shown in FIG. 4B, after receiving the new target coordinates, the controller 31 switches the stepping motor 1 from the maximum speed Vpeak to deceleration so as to reach the new target coordinates.

  FIG. 4C and FIG. 4D show a control example when the new target coordinates are exceeded when the vehicle is decelerated.

  After receiving the new target coordinates, the controller 31 switches the stepping motor 1 from the maximum speed Vpeak to deceleration. After the stepping motor 1 stops, for example, the controller 31 inverts the rotation direction signal, generates a drive pulse, reversely rotates the stepping motor 1, and reaches the new target coordinates. Accelerate and decelerate (FIG. 4C), or accelerate to the maximum speed Vpeak and then decelerate (FIG. 4D).

(Control example 3: When new target coordinates are received during deceleration)
3.1 When the new target coordinates are not reached even after deceleration In this case, the controller 31 causes the stepping motor 1 to reach the new target coordinates from the coordinates when the new target coordinates are received. Accelerate.

  FIG. 5A shows a control example in a case where a new target coordinate is reached without reaching the maximum speed Vpeak.

  As shown in FIG. 5A, after receiving the new target coordinates, the controller 31 switches the stepping motor 1 from deceleration to acceleration, and switches to deceleration so as to reach the new target coordinates during the acceleration.

  FIG. 5B shows a control example in a case where a new target coordinate is reached after reaching the maximum speed Vpeak.

  As shown in FIG. 5B, after receiving the new target coordinates, the controller 31 switches the stepping motor 1 from deceleration to acceleration and continues the acceleration until the maximum speed Vpeak is reached. Then, in the middle of the maximum speed Vpeak, switching to deceleration is performed so as to reach a new target coordinate.

3.2 When a new target coordinate is reached or decelerated when decelerating In this case, the controller 31 causes the stepping motor 1 to reach the new target coordinate from the coordinate when the new target coordinate is received. To slow down.

  In addition, when a new target coordinate is received at the time of deceleration, if it decelerates, it may just arrive at a new target coordinate. In this case, it means that the target coordinates and the new target coordinates are the same coordinates. For this reason, in the above case, it is not particularly necessary to assume. However, according to the control method of the stepping motor according to the embodiment, even when the target coordinates and the new target coordinates are the same coordinates, when the new target coordinates are received at the time of deceleration, the deceleration is performed. Just to reach the new target coordinates. This case is shown in FIG. 5C.

  FIG. 5D and FIG. 5E show examples of control when the new target coordinates are exceeded when decelerated.

  The controller 31 continues to decelerate the stepping motor 1 after receiving the new target coordinates. After the stepping motor 1 stops, for example, the controller 31 inverts the rotation direction signal, generates a drive pulse, reversely rotates the stepping motor 1, and reaches the new target coordinates. Accelerate and decelerate (FIG. 5D), or accelerate to the maximum speed Vpeak and then decelerate (FIG. 5E).

  These control examples 1 to 3 are possible mainly for the following two reasons.

(1) The controller 31 receives coordinates from the coordinate counter 33 before the stepping motor 1 rotates, absolute coordinates during rotation of the stepping motor 1, and relative coordinates based on the stop time (drive pulses output from the start of rotation). The number of pulses necessary to rotate from the coordinates when the new target coordinates are received to the new target coordinates, and (2) the controller 31 changes the coordinates during deceleration The number of drive pulses accumulated in the deceleration coordinate change amount counter 34 is acquired from the amount counter 34, and the stepping motor 1 is able to grasp the number of pulses necessary to stop from the current speed. .

  As described above, according to the embodiment, since the above configurations (1) and (2) are possible, even when the stepping motor 1 is rotating, a new target coordinate is received. A continuous rotation operation toward a new target coordinate accepted during rotation is possible.

  Conventionally, as shown in the reference examples of FIGS. 6A and 6B, the stepping motor cannot be rotated to a new target coordinate unless the rotation to the target coordinate is once completed. For this reason, when the target coordinates are changed in small increments, extra acceleration and deceleration times are generated, and unnecessary time is generated until the new target coordinates are reached.

  In this regard, according to one embodiment, even when the stepping motor 1 is rotating, it is possible to receive a new target coordinate and to continuously rotate toward the new target coordinate received during the rotation. Therefore, even when the target coordinates are changed in small increments, compared to the reference example, there is no extra acceleration and deceleration time, and new target coordinates can be reached in a short time.

  Furthermore, in one embodiment, the acceleration instruction and the deceleration instruction are performed by the controller 31 incorporated in the pulse generator 3 that operates in accordance with an instruction from the host system, in this example, the CPU 2. For this reason, the host system, in this example, the CPU 2 does not issue the acceleration instruction and the deceleration instruction, but only issues the target coordinates to the controller 31. For this reason, the CPU 2 can issue new target coordinates even when the stepping motor 1 is rotating. Thus, in one embodiment, it is possible that the host system only needs to issue the target coordinates. For this reason, the said one embodiment is useful for the use for the use which changes a target coordinate to small increments, for example.

  Thus, according to one embodiment of the present invention, a stepping motor control method and a stepping motor control device capable of rotating the stepping motor to the target coordinates in a short time even if the target coordinates are changed in small increments. And a stepping motor system can be provided.

  As mentioned above, although this invention was demonstrated according to one Embodiment, this invention is not limited to the said one Embodiment, In the range which does not deviate from the main point, it can deform | transform variously. In the embodiment of the present invention, the above-described embodiment is not the only embodiment.

  For example, in the embodiment, the trapezoidal control is exemplified for the acceleration and deceleration in the speed control. However, the acceleration and deceleration can be applied to control other than the trapezoidal control, for example, S-shaped control.

In addition, the system configuration is an example, and any system configuration other than the system configuration described in the embodiment can be used as long as the system configuration can execute the stepping motor control method described in the embodiment.
In addition, the present invention can be variously modified without departing from the gist thereof.

  DESCRIPTION OF SYMBOLS 1 ... Stepping motor, 2 ... CPU, 3 ... Pulse generator, 4 ... Driver, 31 ... Controller, 32 ... Speed counter, 33 ... Coordinate counter, 34 ... Coordinate change amount counter at the time of deceleration

Claims (11)

A stepping motor control method for rotating a stepping motor to a target coordinate according to an output pulse,
Obtain the coordinates before starting the rotation of the stepping motor,
Obtaining a first number of pulses required to rotate the stepping motor from the coordinates before the start of rotation to the target coordinates;
The cumulative number of pulses output from the start of rotation of the stepping motor is obtained as the second number of pulses,
Subtracting the second pulse number from the first pulse number to obtain a third pulse number necessary to reach the target coordinates,
Obtaining a fourth number of pulses required until the stepping motor stops from the current speed;
Based on the third pulse number and the fourth pulse number, the stepping motor is accelerated from its current speed, decelerated, or maximum to rotate the stepping motor toward the target coordinates. A stepping motor control method comprising: determining whether to maintain a speed. If the stepping motor does not reach the target coordinates even if it is immediately decelerated from the current coordinates, the stepping motor is accelerated or the maximum speed is maintained,
2. The method of controlling a stepping motor according to claim 1, wherein when the stepping motor reaches or exceeds the target coordinate when it immediately decelerates from a current coordinate, the stepping motor is decelerated.   While the stepping motor accelerates the stepping motor, the fourth pulse number adds and accumulates the output pulses, and from the accumulated pulse number, outputs the pulses output while decelerating the stepping motor. The stepping motor control method according to claim 1, wherein the stepping motor control method is obtained by subtraction. Accept new target coordinates when the stepping motor is rotating,
A fifth pulse number required to reach the new target coordinate is obtained by subtracting the coordinates before the rotation start from the new target coordinate, and the first pulse is obtained with the fifth pulse number. The stepping motor control method according to claim 1, wherein the number is replaced.   4. The stepping motor control method according to claim 3, wherein the number of pulses required to reach a predetermined speed from zero speed is equal to the number of pulses required to reach the speed zero from the predetermined speed. . A stepping motor control device for rotating a stepping motor to a target coordinate according to an output pulse,
Means for obtaining coordinates before the rotation of the stepping motor is started;
Means for obtaining a first number of pulses necessary to reach the target coordinates from the coordinates before the rotation start;
Means for obtaining a second pulse number which is the cumulative pulse number output after the start of rotation;
Means for obtaining a third pulse number necessary to reach the target coordinates by subtracting the second pulse number from the first pulse number;
Means for obtaining a fourth number of pulses required to stop from the current speed;
Based on the third pulse number and the fourth pulse number, the stepping motor is accelerated from its current speed, decelerated, or maximum to rotate the stepping motor toward the target coordinates. A means of determining whether to maintain speed,
A stepping motor control device comprising: If the stepping motor does not reach the target coordinates even if it is immediately decelerated from the current coordinates, the stepping motor is accelerated or the maximum speed is maintained,
The stepping motor control device according to claim 6, wherein the stepping motor decelerates the stepping motor when reaching or exceeding the target coordinate when the stepping motor decelerates immediately from a current coordinate.   While the stepping motor accelerates the stepping motor, the fourth pulse number adds and accumulates the output pulses, and from the accumulated pulse number, outputs the pulses output while decelerating the stepping motor. The stepping motor control device according to claim 6, wherein the stepping motor control device is obtained by subtraction. Accept new target coordinates when the stepping motor is rotating,
A fifth pulse number required to reach the new target coordinate is obtained by subtracting the coordinates before the rotation start from the new target coordinate, and the first pulse is obtained with the fifth pulse number. 9. The stepping motor control apparatus according to claim 6, wherein the number is replaced.   The stepping motor control device according to claim 8, wherein the number of pulses required to reach a predetermined speed from zero speed is equal to the number of pulses required to reach the speed zero from the predetermined speed. . A stepping motor,
An arithmetic device capable of issuing a target coordinate and issuing a new target coordinate different from the target coordinate after issuing the target coordinate;
A pulse generator that receives the target coordinates and the new target coordinates and generates a driving pulse for rotating the stepping motor;
A driver for receiving the drive pulse and rotating the stepping motor;
The pulse generator is
A controller that receives the target coordinates and the new target coordinates and issues an acceleration instruction and a deceleration instruction;
A speed counter that receives the acceleration instruction and the deceleration instruction and generates speed data;
A coordinate counter including a region for storing the coordinates of the stepping motor and a region for storing the cumulative number of pulses output from the start of rotation, and generating a drive pulse for rotating the stepping motor in response to the speed data;
While receiving the acceleration instruction and the deceleration instruction and accelerating the stepping motor, the driving pulses are added and accumulated every time the driving pulses are generated, and the stepping is calculated from the accumulated number of driving pulses. A deceleration coordinate change amount counter that subtracts the drive pulse every time the drive pulse is generated while decelerating the motor,
The controller is
Obtain the coordinates before starting the rotation of the stepping motor from the coordinate counter,
Obtaining a first number of pulses required to rotate the stepping motor from the coordinates before the start of rotation to the target coordinates;
The cumulative number of pulses output from the start of rotation of the stepping motor is obtained from the coordinate counter as the second number of pulses,
Subtracting the second pulse number from the first pulse number to obtain a third pulse number necessary to reach the target coordinates,
The fourth pulse number required until the stepping motor stops from the current speed is acquired from the coordinate change counter during deceleration,
Based on the third pulse number and the fourth pulse number, the stepping motor is accelerated from its current speed, decelerated, or maximum to rotate the stepping motor toward the target coordinates. A stepping motor system for determining whether to maintain speed.

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