JP2687639B2 - Motor control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for feedback controlling a motor, and more particularly, to rotate a motor output shaft in a fixed direction to accurately perform positioning control a number of times for a long time. The present invention relates to a control device for a motor that can be performed.

(Prior Art) Generally, various moving mechanisms provided in a machine tool or the like are driven by a control motor such as a servo motor. The control motor is subjected to so-called feedback control so that its moving mechanism can be operated accurately in accordance with the machining process.

Conventionally, among such moving mechanisms, such a control motor is also used for a mechanism called an NC turret that automatically switches a machining tool, for example, and is controlled by a control device as shown in FIG. There is something.

As shown in the drawing, the turret 2 to which various processing tools 1 are attached is driven by a servo motor 3 to position each processing tool 1 with respect to a work (not shown).

The output shaft of the servomotor 3 is connected to the rotary shaft of the turret 2 via a decelerator 4, and when the rotary shaft is rotated by the servomotor 3, the turret 2 main body rotates, and the machining tool 1 attached thereto Are positioned at predetermined processing positions.

The turret 2 is usually attached with the processing tools 1 in accordance with the order of the processing steps, and when the turret 2 rotates in one direction, the respective processing tools 1 sequentially perform predetermined processing on the workpiece. ing.

The servo motor 3 for rotating the turret 2 in one direction in this way is controlled by, for example, the control device 5 shown in the figure.

The servo motor 3 is provided with a pulse generator (hereinafter referred to as PG) 6 that outputs a pulse signal of a predetermined cycle according to the rotation of the output shaft.

The control device 5 for controlling the servo motor 3 is provided with a current angle counter 7 for inputting the pulse signal output from the PG 6 thereof.
Is configured to accumulate and count the pulse signals and output the current rotation angle of the output shaft from a predetermined reference angle for positioning the output shaft to the subtractor 9.

Further, the control device 5 is provided with a target angle memory 8 that stores a target rotation angle of the output shaft for positioning the turret 2. The target angle memory 8 stores a target angle from the reference angle, which is a target value for rotating the output shaft of the servomotor 3, and the target angle memory 8 sequentially outputs the target angle to the subtractor 9. It is supposed to do.

The subtractor 9 that inputs the current rotation angle and the target angle calculates the movement angle amount by subtracting the current rotation angle from the target angle, and outputs this to the control unit 10. That is, the control unit 10 receives the movement angle amount calculated for moving the output shaft from the current rotation angle to the target angle. This movement angle amount becomes smaller as the rotation angle of the output shaft approaches the target angle, and is not output at the target angle.

Then, the control unit 10 which inputs this movement angle amount outputs a drive signal for driving the servo motor 3 in accordance with this movement angle amount to the drive unit 11, and the drive unit 11 causes the subtractor 9 to operate in response to this drive signal. Driving power for rotating the output shaft by the calculated movement angle amount is supplied to the servo motor 3.

Therefore, the control device 5 drives the servo motor 3 by the deviation amount between the target angle stored in the target angle memory 8 and the current rotation angle of the output shaft detected by the current angle counter 7, and servos to the target angle. The turret 2 is positioned by rotating the output shaft of the motor 3.

(Problems to be Solved by the Invention) However, in such a conventional control device, the current angle counter counts the pulse signals output from the PG to obtain the current rotation angle of the output shaft. Therefore, if the output shaft rotates until it exceeds the capacity of this counter, that is, if processing is performed for a long time to rotate the turret a large number of times in one direction, so-called overflow occurs in the current angle counter, When this happens, the current angle counter is reset, so the amount of movement angle input to the control unit differs from the actually required amount of movement angle, and the turret is positioned at the wrong position. Occurs. For example, if the number of pulses that the current angle counter can count is 800, if the output shaft rotates until the number of pulses output by the PG exceeds this 800 pulses, the current angle counter will display the number of input pulses. It will be reset when it reaches 800, and the current rotation angle input to the subtractor will be zero. As a result, the subtractor subtracts this current rotation angle from the target rotation angle, so that the movement angle amount output to the control unit becomes an excessive movement angle amount than the actually required movement angle amount, and the turret It will be positioned in the wrong position.

Therefore, in a machine tool provided with a turret controlled by such a control device, it is not possible to perform machining for a long period of time, which is performed by continuously positioning the turret many times, thereby improving productivity. There was a problem such as not being able to do it.

The present invention has been made in order to solve such a conventional problem, and a motor capable of accurately performing a large number of positioning controls for a long time by rotating the output shaft of the motor in a fixed direction. An object is to provide a control device.

(Means for Solving the Problem) The present invention for achieving the above-mentioned object is a motor control device that rotates an output shaft of a motor only in a fixed direction to perform positioning a plurality of times. A pulse generator that outputs a pulse signal each time the shaft rotates by a predetermined angle, and the number of pulse signals output from the pulse generator are cumulatively counted, and the motor output from a reference position defined on the output shaft of the motor Rotation angle detection means for detecting the rotation angle of the shaft, front angle storage means for storing the rotation angle at the end of the previous positioning detected by the rotation angle detection means, rotation angle detected by the rotation angle detection means, and A current angle calculation unit that calculates a current rotation angle of the output shaft of the motor based on the rotation angle stored in the front angle storage unit, and a current position calculation unit. Therefore, based on the target angle storage means for storing the target rotation angle for rotating the output shaft of the motor, the rotation angle calculated by the current angle calculation means and the rotation angle stored by the target angle storage means,
The rotation angle control means for determining the rotation angle amount of the output shaft in the current positioning, and the drive control means for driving the motor based on the rotation angle determined by the rotation angle control means are provided. The control means stores the rotation angle detected by the rotation angle detection means, resets the rotation angles of the front angle storage means and the rotation angle detection means each time the rotation angle reaches a unit rotation angle, and It is characterized in that the number of resets is stored.

(Operation) The present invention configured as described above operates as follows.

When the output shaft of the motor rotates, the pulse signal is output from the pulse generator. This pulse signal is 1 every time the output shaft of the motor rotates a predetermined angle (for example, 0.2 degrees).
Pulse output. The rotation angle detecting means increments the count number by 1 each time the pulse signal is input. The rotation angle detecting means can count the pulse signals corresponding to the unit rotation of the output shaft of the motor. For example, in the case of an encoder that outputs a pulse signal every time the output shaft of the motor rotates 0.2 degrees, the counter is capable of counting 1800 (when the unit rotation is 1 rotation).

The count number of the rotation angle detection means is stored by the angle control means, and when the count number reaches the count number for the unit rotation of the output shaft of the motor, the count number is reset to 0 by the angle control means. Therefore, the count number of the rotation angle detection unit and the count number of the rotation angle detection unit stored in the angle control unit are always within the unit rotation of the output shaft of the motor.

On the other hand, the front angle storage means stores the count number of the rotation angle detection means when the output shaft of the motor rotates to the target angle. This count number is also reset to 0 at the same time as the rotation angle detection means is reset. . Therefore, the count number of the front angle storage means is always a count number other than the unit rotation of the output shaft of the motor.

The current angle calculation means calculates how much the output shaft of the motor has rotated from the reference position based on the count number of the rotation angle detection means and the count number of the previous angle storage means. The rotation angle calculated by the present angle detection means is always within the unit rotation of the output shaft of the motor.

The target angle storage means stores a target angle (not necessarily an angle within a unit rotation) from a reference position defined on the output shaft of the motor, but the movement amount calculation means uses the target angle storage means. From the reference angle stored in the reference position and the count number and reset number of the rotation angle detection unit stored in the angle control unit to the target angle (not necessarily the movement amount within a unit rotation) ) Is calculated.

The drive control means drives the motor based on this movement amount.

(Embodiment) Hereinafter, a motor control device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a motor control device according to the present invention, and FIG. 2 is a flowchart showing an operation of the motor control device. Further, FIG. 3 is a view exemplifying the angle data output in A to F shown in FIG. 1 when the motor is controlled by the control device, and FIG. 4 shows another embodiment. The schematic block diagram of the control apparatus of the motor which concerns on this invention is shown. In FIGS. 1 and 4, the same members as those described in the related art are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, a motor control device according to the present invention.
20 is the servo motor 3 until the output shaft rotates to the target angle stored in the target angle memory 8 as in the conventional control device.
Is driven.

The control switch 20 is provided with a PG 6, which constitutes the rotation angle detecting means, a current angle counter 7, a subtractor 9 and a front angle memory 21.

The current angle counter 7 is the same as the conventional one and the PG6
By inputting the pulse signal output from the output shaft, the current rotation angle of the output shaft from the predetermined reference angle for positioning the output shaft is output to the subtractor 9.

Then, the subtractor 9 for inputting these rotation angles uses the front angle memory 21 based on the rotation angles currently input from the counter 7.
The input rotation angle is subtracted from. Front angle memory 21
Is a memory for storing the rotation angle of the output shaft output from the current angle counter 7 when the servo motor 3 is stopped at the time of the previously performed positioning among a plurality of consecutively performed positionings. Therefore, the subtraction performed by the subtractor 9 is a process of calculating the rotational movement amount (hereinafter referred to as the movement angle amount) in which the output shaft is rotated only by the positioning performed this time.

The calculated movement angle amount is output to the adder 23 as the current angle calculation means via the data expander 22.

In the data extender 22, the adder 23 calculates 16-bit angle data indicating the rotation angle amount output by the subtractor 32 32
This is for performing extended conversion into bit data, and the conventional subtractor 9 is used and the adder 23 having a high processing speed is used, so that it is provided for matching the number of bits representing one data. However, if the angle data output by the subtractor 9 and the data calculated by the adder 23 are matched, it is unnecessary.

Then, the adder 23, which inputs the movement angle amount calculated by the subtractor 9 in this way, adds the rotation angle stored in the front angle memory 27 and the movement angle amount.

The front angle memory 27 stores the rotation angle (front angle) of the output shaft output from the current angle counter 7 when the servo motor 3 is stopped at the time of the positioning performed last time, similarly to the front angle memory 21 described above. It is a memory for storing and outputs the front angle to the adder 23.

Then, the adder 23 calculates the current rotation angle of the output shaft from the reference angle (hereinafter referred to as the current angle) by adding the movement angle amount and the previous angle, and stores this in the current angle memory 24. It is designed to be remembered.

The current rotation angle of the output shaft is output from the current angle memory 24 to the front angle memories 21 and 27 by the angle control unit 25 every time the positioning of the output shaft is completed.
The rotation angle output to the front angle memories 21 and 27 is stored here and becomes the data of the previous rotation angle of the output shaft used at the next positioning.

The present angle stored in the present angle memory 24 is calculated by the angle control unit 25 as the angle control means so that the present angle is less than one rotation from the reference angle.

When the absolute value of the current angle stored in the current angle memory 24 becomes 360 degrees or more, the angle control section 25 outputs a value obtained by subtracting 360 degrees from this absolute value to the subtractor 26. ing. That is, the current angle memory 24 always outputs to the subtractor 26 the current angle which is less than one rotation from the reference angle of the output shaft.

Further, the angle control unit 25 uses the same target angle memory 8 as the conventional one.
In order to correspond to the above-mentioned current angle, the target angle stored in 1 is also calculated so as to be less than one rotation with respect to the reference angle.

The angle control unit 25 stores the number of times that the absolute value of the current angle stored in the current angle memory 24 becomes 360 degrees or more, and subtracts the rotation angle for this number of times from the absolute value of the target angle in the target angle memory 8. The target angle is output to the subtractor 26. That is, like the current angle memory 24, the target angle memory 8 always outputs the target angle for less than one rotation to the subtractor 26 with respect to the reference angle of the output shaft.

Further, when the absolute value of the current angle stored in the current angle memory 24 becomes 360 degrees or more, the angle control unit 25 resets the current angle counter 7 and the previous angle memory 21, and the subtractor 9 newly adds the new value. At the same time that the amount of movement angle is obtained, the front angle memory 27 is also reset so that the current angle memory 24 can store a new current angle.

Then, the subtractor 26 for inputting the current angle and the target angle which have become less than one rotation with respect to the reference angle in this way.
Like the conventional subtractor, subtracts the current angle from the target angle to calculate the movement angle amount, and outputs it to the control unit 10.

The control unit 10 controls the servo motor 3 according to the input movement amount.
The drive signal for driving the
Supplies to the servomotor 3 drive power for rotating the output shaft by the movement angle amount calculated by the subtractor 26 according to the drive signal.

The motor control device 20 of the present invention configured as described above
Operates based on the flowchart shown in FIG.

First, when the movement rotation amount calculated by the subtractor 9 is input to the adder 23, the adder 23 adds the movement rotation amount and the front angle stored in the front angle memory 27 to calculate the current angle. , This is stored in the current angle memory 24. Then, the angle control unit 25 inputs the current angle θ1 stored in the current angle memory 24 (step 1) and determines whether the absolute value of the current angle θ1 is 360 degrees or more. If the absolute value of the current angle θ1 is not equal to or greater than 360 degrees, the angle control unit 25 outputs the input target angle θ1 as it is to the subtractor 26 (step 2).

On the other hand, when the absolute value of the input current angle θ1 is 360 degrees or more, the angle control unit 25 stores the number of times the absolute value of the current angle θ1 is 360 degrees or more in the flag n (step 3) The value obtained by subtracting 360 degrees from the absolute value of the target angle θ1 is output to the subtractor 26. Further, at this time, the angle control unit 25 resets the current angle counter 7, the front angle memory 21, and the front angle memory 27 so that the subtracter 9 can newly obtain the moving angle amount of the output shaft from the reference angle. At the same time, the current angle of the output shaft from the reference angle can be newly stored in the current angle memory 24 (step 4).

Next, the angle control unit 25 inputs the target angle θ2 stored in the target angle memory 8 (step 5).

Then, the angle control unit 25 determines that the absolute value of the target angle θ2 is
Whether or not the absolute value of the present angle θ1 is equal to or greater than the number of rotations equal to the number of rotations of 360 degrees or more, that is, the number of rotations equal to or greater than the number of rotations stored in the flag n in step 3 If the absolute value of the target angle θ2 is not equal to or more than that angle, the input target angle θ2 is directly output to the subtractor 26 (step 6).

On the other hand, when the absolute value of the target angle θ2 is equal to or greater than that angle, the angle control unit 25 subtracts the number of rotations equal to this number of times from the absolute value of the target angle θ2, and subtracts this. It is output to the container 26 (step 7).

As a result, the subtractor 26 subtracts the current angle from the target angle to calculate the movement amount by inputting the target angle and the current angle which are always less than one rotation with respect to the reference angle of the output shaft. It is calculated and output to the control unit 10. Then, the control unit 10 outputs a drive signal for driving the servo motor 3 according to the input movement amount to the drive unit 11,
The drive controller 11 supplies the servomotor 3 with drive power for rotating the output shaft by the amount of movement calculated by the subtractor 26 in response to the drive signal.

Therefore, the servomotor 3 drives the servomotor 3 by the amount of movement calculated by the subtractor 26, that is, the difference between the current angle and the target angle, rotates the output shaft to the target angle, and positions the turret 2. it can.

Here, a specific manner in which the servomotor 3 is controlled by the control device 20 will be described with reference to FIG. FIG. 3 shows the angle amounts output in A to F shown in FIG. 1 according to the state of the output shaft of the servomotor 3. Incidentally, here, the servo motor 3 is assumed to be controlled from the initial state in which the output shaft is at the reference angle,
In addition, as shown in FIG.
It is assumed that the target angles of 0,430,830 are stored in advance.

First, when the control device 20 operates, the angle control unit 25 inputs the current angle stored in the current angle memory 24, as described above, and determines whether the absolute value of this current angle is 360 degrees or more. To determine. Since the output shaft does not rotate at startup, the angle of the output shaft is 0 degree and C, D, E, F are 0 degree.

Next, the angle control unit 25 inputs the target angle stored in the target angle memory 8, and the absolute value of this target angle is the same as the number of rotations when the absolute value of the current angle becomes 360 degrees or more. Although it is determined whether the angle is equal to or greater than the minute angle, the output shaft has not yet rotated in the same manner, so that the target angle of 90 degrees is output to A.

Then, 90 degrees is output to B, and the servo motor 3 is driven until the output shaft reaches 90 degrees.

Then, when the output axis becomes 90 degrees, C becomes 90 degrees, and D,
Since E is 0 degree, the current angle calculated by the subtractor 9 and the adder 23 and stored in the current angle memory 24 is 90 degrees.

Next, when the positioning is performed, the current angle stored in the current angle memory 24 is 90 degrees, so the angle control unit 25 outputs the 90 degrees as it is to the subtractor 26, and F becomes 90 degrees. The next target angle of 320 degrees is also output to the subtractor 26 as it is, and A becomes 320 degrees.

Then, in B, 320-90 = 230 degrees, and the control unit 10 rotates the output shaft by 230 degrees.

When the output shaft rotates by 230 degrees, the counter 7 currently stores the angle amount from the reference angle to the present, so C is 320.
Degree. Further, since the angle (90 degrees) that was previously positioned is stored in the front memory 21, D becomes 90 degrees.

Then, in the current angle memory 24, the 90 degrees (E) stored in the previous angle memory 27 is added to the 320-90 = 230 degrees calculated by the subtractor 9 by the adder 23, and 230 + 90 = 3 degrees.
The current angle of 20 degrees is stored.

When positioning is further continued, the current angle memory
Since the current angle stored in 24 is 320 degrees, the angle control unit 25 outputs the 320 degrees as it is to the subtractor 26, and F is 3
It will be 20 degrees. The next target angle of 430 degrees is also subtracted by the subtractor 2
It is output to 6 and A becomes 430 degrees.

Then, in B, 430−320 = 110 degrees, and the control unit 10 rotates the output shaft by 110 degrees.

As a result, when the output shaft rotates 40 degrees out of 110 degrees, the angle C currently output by the counter 7 becomes 360 degrees. Further, since the angle (320 degrees) that was previously positioned is stored in the front memory 21, D becomes 320 degrees. As a result, the current angle memory 24 is stored in the previous angle memory 27 (E).
Is 320 degrees, 360-320 + 320 = 360 degrees is stored.

Then, the angle control unit 25 determines that the current angle stored in the current angle memory 24 is 360 degrees, and therefore the subtractor 26 sets the current angle to 3 degrees.
60-360 = 0 degree is output. Further, the angle control unit 25 sets the target angle (430 degrees) to 430-360 = 70 degrees and outputs it to the subtractor 26. As a result, F becomes 0 degrees, A becomes 70 degrees, and B
Becomes 70 degrees corresponding to the remaining angle, and the control unit 10 rotates the output shaft by the remaining 70 degrees.

Furthermore, since the current angle stored in the current angle memory 24 has reached 360 degrees, the angle control unit 25 resets the current angle counter 7, the front angle memory 21, and the front angle memory 27,
The remaining angle of movement up to 70 degrees is calculated by the subtracter 9, and the current angle from the reference angle is newly stored in the current angle memory 24.

And when the output shaft finishes rotating by 70 degrees, C becomes 70 degrees,
D is 0 degree, E is 0 degree, and the current angle memory 24 has 70
−0 + 0 = 70 degrees is stored.

Similarly, when the next positioning is performed, the current angle memory
Since the current angle stored in 24 is 70 degrees, E and F are
It will be 70 degrees.

Here, since the flag n has already been set to 1, the angle control unit 25 outputs the target angle 830 degrees to the subtractor 26 as 830−360 × 1 = 470 degrees. (A becomes 470 degrees.) Then, B becomes 470−70 = 400 degrees, and the control unit 10 rotates the output shaft by 400 degrees.

As a result, when the output shaft rotates 310 degrees out of the 400 degrees, the angle C currently output by the counter 7 becomes 360 degrees. Further, since the angle (70) positioned in the front is stored in the front memory 21, D becomes 70 degrees.

Since the front angle memory 27 stores 70 degrees, the current angle memory 24 stores 360-70 + 70 = 360 degrees. Then, the angle control unit 25 displays the current angle memory.
Since the current angle that was chrysanthemum on 24 is 360 degrees again,
The subtracter 26 outputs the current angle of 360-360 = 0 degree.
Further, the angle control unit 25 sets the target angle (470 degrees) to 470-360 = 1.
It is set to 10 degrees and output to the subtractor 26. As a result, F is 0
Degrees, A becomes 110, B becomes 110 degrees for the remaining angles,
The control unit 10 rotates the output shaft by 110 degrees remaining. At the same time, the angle control unit 25 resets the current angle counter 7, the front angle memory 21, and the front angle memory 27 because the current angle stored in the current angle memory 24 becomes 360 degrees, and the remaining 11
The moving angle amount up to 0 degrees is calculated by the subtracter 9, and the current angle from the reference angle is newly stored in the current angle memory 24.

Then, when the output shaft has finished rotating 110 degrees, C becomes 110
The degree, D is 0 degree, and E is 0 degree, and the present angle memory 24 stores the present angle of 110-0 + 0 = 110 degrees.

Therefore, the current angle thus calculated by the adder 23 is always less than one rotation with respect to the reference angle by the angle control unit 25, and thus the current rotation angle cannot be accurately detected as in the conventional case. The state does not occur, and it becomes possible to perform positioning control over a long period of time by rotating the output shaft of the motor a large number in one direction.

In addition to the above embodiment, as shown in FIG. 4, the rotation angle from the reference angle output by the current angle counter 7 to the current rotation angle is directly input to the adder 23. The counter 7 is reset by the subtracter 26 when the angle difference between the target angle and the current angle becomes 0 degrees, or when the absolute value of the current angle becomes 360 degrees by the angle control unit 25, respectively. May be. By doing so, the current angle counter 7 outputs the movement angle up to the present from the previously positioned rotation angle, so that the adder 23 determines this movement angle amount and The current angle can be calculated by adding the previous rotation angle, and this current angle can be stored in the current angle memory 24.
The angle control unit 25 always sets the present angle to 1 with respect to the reference angle.
By making the angle less than the rotation and outputting the angle to the subtractor 26, it becomes possible to perform the positioning control for a long time in which the output shaft of the motor is rotated many times in one direction as in the above embodiment.

(Effects of the Invention) As is clear from the above description, the present invention has the following effects.

Since the count number of the rotation angle detecting means is always within the unit rotation amount of the output shaft of the motor, and the output shaft can be rotated to the target rotation angle, the conventional limit Even when using a rotation angle detection means that can count only the counted number,
It is possible to avoid a situation in which the rotation angle cannot be accurately detected due to the overflow of the count of the rotation angle detection means, and it is possible to perform highly accurate positioning control for rotating the output shaft of the motor in one direction. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a motor control device according to the present invention,
FIG. 2 is a flow chart showing the operation of the motor control device, and FIG. 3 is a diagram exemplifying the angle data output in A to F shown in FIG. 1 when the motor is controlled by the control device. FIG. 5 is a schematic configuration diagram of a motor control device according to another embodiment of the present invention, and FIG. 5 is an explanatory diagram of a conventional motor control device. 3 ... Servo motor, 6 ... PG (rotation angle detecting means),
7 ... Current angle counter (rotation angle detecting means), 8 ...
Target angle memory (target angle storage means), 9 ... subtractor (rotation angle detection means), 10 ... control section (drive control means), 11 ... drive section (drive control means), 21 ... front angle memory (Rotation angle detection means), 23 ... adder (current angle calculation means), 24 ... current angle memory (current angle calculation means), 25 ... angle control unit (angle control means), 26 ... subtractor ( Drive control means), 27 ... Front angle memory (front angle storage means).

Claims (1)

(57) [Claims] 1. A control device for a motor (3) that performs positioning a plurality of times by rotating the output shaft of the motor (3) only in a fixed direction, wherein the output shaft of the motor (3) has a predetermined angle. A pulse generator (6) that outputs a pulse signal each time it rotates, and cumulatively counts the number of pulse signals that are output from the pulse generator (6), from the reference position defined on the output shaft of the motor (3). A rotation angle detecting means (7) for detecting the rotation angle of the output shaft of the motor (3), and a previous angle for storing the rotation angle at the end of the previous positioning detected by the rotation angle detecting means (7). Based on the storage means (21, 27), the rotation angle detected by the rotation angle detection means (7) and the rotation angle stored by the front angle storage means (21, 27), the current motor (3 ) Output shaft rotation angle A current angle calculation means (23), a target angle storage means (8) that stores a target rotation angle for rotating the output shaft of the motor (3), and a current angle calculation means (23). Rotation angle control means (24, 25, 26) for determining the rotation angle amount of the output shaft of the motor (3) based on the rotation angle and the rotation angle stored in the target angle storage means (8), Drive control means (1) for driving the motor (3) based on the rotation angle determined by the rotation angle control means (24, 25, 26).
0, 11) and the rotation angle control means (24, 25, 26) stores the rotation angle detected by the rotation angle detection means (7), and this rotation angle is a unit rotation angle. The motor control device is characterized in that the rotation angles of the front angle storage means (21, 27) and the rotation angle detection means (7) are reset each time the above-mentioned is reached, and the number of resets is stored.