JPH1066394A - Method and device for driving pulse motor and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the noise of a pulse motor when the driving of the motor is started or the motor is stopped by changing the shape of the waveform of the driving current of the motor by changing the driving speed of the motor for a fixed period of time at the time of starting the driving of the motor or stopping the motor. SOLUTION: A microcomputer 7 inputs signals outputted from the output terminals E and F of a PWM unit 7a to driver circuits 1 and 2 at a fixed frequency. Since the frequency is high, the electric currents corresponding to the PWM duty ratio flow to motor windings 3 and 4 due to the influences of the inductances of the windings 3 and 4. Therefore, when the PWM duty ratio is changed to a sine-wave state, a pulse motor 5 can be driven in a sine-wave driving mode in which the vibration and noise of the motor 5 are considered to become less. The PWM duty ratio is decided by successively reading out duty ratio data by interrupting the microcomputer 7 in accordance with a timer. When the motor 5 is accelerated or decelerated at the time of starting the driving of the motor 5 and stopping the motor 5 by interrupting the microcomputer 7, the waveform of the driving current of the motor 5 becomes smoother and the noise of the motor 5 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse motor drive control method and device for controlling a pulse motor, and a storage medium storing a program for controlling the pulse motor drive control device.

[0002]

2. Description of the Related Art Conventionally, a pulse motor has been used as a drive source for OA (office automation) equipment and the like because a rotation angle and a rotation speed can be accurately controlled by open control.

In addition, since the rotation angle of the pulse motor with respect to the number of stepping pulses is constant, the position of the stepping pulse can be detected by incrementing the stepping pulse as it is, and an encoder for the position detection is not required. It is also used as a lens control source of an imaging device such as a camera.

However, there is a problem that the noise is increased when the pulse motor is driven, and the driving current waveform of the pulse motor is changed from the rectangular wave of FIG. 22B to the sine waveform as shown in FIG. By doing so, the noise is reduced.

[0005]

However, in the above-mentioned prior art, the driving current waveform of the pulse motor is set to a sine wave in order to reduce the noise. As shown in c), the waveform is not smooth even with the sine wave drive, which causes noise.

In particular, there is a driving pattern as shown in FIG. 22D in which the driving and stopping of the lens are repeated in a short period of time when the focusing operation is performed when driving the lens of the photographing apparatus. Sometimes, driving and stopping the lens are repeated many times, so that noise becomes a serious problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and a first object of the present invention is to provide a pulse which can reduce noise at the start or stop of driving of a motor. An object of the present invention is to provide a motor control method and device.

Another object of the present invention is to provide a storage medium storing a program capable of smoothly controlling the pulse motor control device of the present invention.

[0009]

According to a first aspect of the present invention, there is provided a pulse motor drive control method, comprising the steps of: driving a pulse motor in a substantially sinusoidal wave; and controlling the drive step. And a waveform changing step of changing the shape of the drive current waveform by changing the drive speed for a certain period when the drive is started or stopped.

According to a second aspect of the present invention, there is provided a pulse motor drive control method according to the first aspect of the present invention. The method further comprises a time changing step of changing the time for changing the shape of the drive current waveform by changing the drive speed when the motor is stopped.

According to a third aspect of the present invention, there is provided a pulse motor drive control method according to the first aspect of the present invention, comprising the steps of: Alternatively, the method has a waveform changing step of changing the shape of the drive current waveform by changing the drive speed at the time of stop.

According to a fourth aspect of the present invention, there is provided a pulse motor drive control method for achieving the first object.
At least two PWM signal generating steps capable of setting a duty ratio for generating an M (pulse width modulation) signal, a driving step of driving a pulse motor with a substantially sinusoidal wave using an output signal from the PWM signal generating step, It is characterized by comprising a drive control step of controlling and a waveform changing step of changing the shape of the drive current waveform by changing the duty ratio of PWM for a certain period at the start or stop of driving.

According to a fifth aspect of the present invention, there is provided a pulse motor drive control method according to the fourth aspect of the present invention. It is characterized by having a waveform changing step of changing the shape of the drive current waveform by changing the PWM duty ratio and the drive speed at the time of stop.

According to a sixth aspect of the present invention, there is provided a pulse motor drive control method according to the fourth aspect of the present invention. It has a period changing step of changing a period for changing the shape of the drive current waveform by changing the duty ratio of the PWM at the time of stop.

According to a seventh aspect of the present invention, there is provided a pulse motor drive control method according to the fourth aspect of the present invention, wherein when the drive is started in accordance with the drive phase position. Alternatively, it has a waveform changing step of changing the shape of the drive current waveform by changing the duty ratio of the PWM at the time of stop.

In order to achieve the first object, a pulse motor drive control method according to claim 8 of the present invention provides a drive step of driving a pulse motor with a substantially sine wave, and a drive control step of controlling the drive step. And a waveform changing step of changing the shape of the drive current waveform by changing the drive period and the duty ratio and the drive speed of the PWM at the start or stop of the drive according to the drive speed or the drive start and stop phases. It is a feature.

In order to achieve the first object, a pulse motor drive control device according to a ninth aspect of the present invention includes a pulse motor, a drive unit for driving the pulse motor with a substantially sine wave, and a drive unit for driving the pulse motor. It is characterized by comprising drive control means for controlling, and waveform changing means for changing the shape of the drive current waveform by changing the drive speed for a certain period at the start or stop of driving.

According to a tenth aspect of the present invention, there is provided a pulse motor drive control device according to the ninth aspect of the present invention, wherein the pulse motor drive control device according to the ninth aspect has a function of: It is characterized by comprising time changing means for changing the drive speed and changing the time for changing the shape of the drive current waveform when stopped.

In order to achieve the first object, a pulse motor drive control device according to claim 11 of the present invention is the pulse motor drive control device according to claim 9, wherein the drive start time according to the drive phase position. Alternatively, there is provided a waveform changing means for changing the shape of the drive current waveform by changing the drive speed at the time of stop.

According to a twelfth aspect of the present invention, there is provided a pulse motor drive control apparatus according to a twelfth aspect of the present invention, comprising: a pulse motor; and at least two PWM signal generating means capable of setting a duty ratio for generating a PWM signal. A driving means for driving the pulse motor in a substantially sinusoidal manner with an output signal from the PWM signal generating means, a driving control means for controlling the driving means, and changing a duty ratio of the PWM for a certain period at the time of starting or stopping the driving. And a waveform changing means for changing the shape of the drive current waveform.

According to a thirteenth aspect of the present invention, there is provided a pulse motor drive control device according to the twelfth aspect of the present invention, wherein the drive is started at the start of the drive or in accordance with the drive speed. Waveform changing means for changing the shape of the drive current waveform by changing the PWM duty ratio and the drive speed when the motor is stopped is provided.

According to a fourteenth aspect of the present invention, there is provided a pulse motor drive control device according to the twelfth aspect of the present invention, wherein the pulse motor drive control device according to the twelfth aspect of the present invention is provided at the start of drive or at the start of drive according to the drive speed. A period changing means for changing a period during which the shape of the drive current waveform is changed by changing the duty ratio of the PWM at the time of stoppage is provided.

According to a fifteenth aspect of the present invention, there is provided a pulse motor drive control device according to the twelfth aspect of the present invention, wherein a drive is started in accordance with a drive phase position. Alternatively, there is provided a waveform changing means for changing the shape of the drive current waveform by changing the PWM duty ratio at the time of stop.

In order to achieve the first object, a pulse motor drive control device according to a sixteenth aspect of the present invention comprises: a pulse motor; a drive unit for driving the pulse motor substantially in a sine wave; Drive control means for controlling, and waveform changing means for changing the shape of the drive current waveform by changing the drive period, the duty ratio of PWM and the drive speed at the start or stop of the drive according to the drive speed or the drive start and stop phases And characterized in that:

In order to achieve the second object, a storage medium according to a seventeenth aspect of the present invention is a storage medium for storing a program for controlling a pulse motor drive control device. A driving module of a driving step to be driven, a driving control module of a driving control step for controlling the driving step, and a first method of changing the shape of the driving current waveform by changing the driving speed for a certain period at the time of starting or stopping driving. A program having a first waveform changing module in a waveform changing step is stored.

In order to achieve the second object, a storage medium according to claim 18 of the present invention is the storage medium according to claim 17, wherein the program is executed at the time of starting or stopping the driving according to the driving speed. It has a time changing module of a time changing step of changing the time for changing the shape of the drive current waveform by changing the drive speed.

In order to achieve the second object, a storage medium according to a nineteenth aspect of the present invention is the storage medium according to the seventeenth aspect, wherein the program starts or stops driving according to a driving phase position. A second waveform changing module in a second waveform changing step of changing the shape of the driving current waveform by changing the driving speed at times.

In order to achieve the second object, a storage medium according to a twentieth aspect of the present invention provides a storage medium having at least two PWM signal generation steps capable of setting a duty ratio for generating a PWM (pulse width modulation) signal. A signal generation module, a drive module of a drive step for driving the pulse motor with a substantially sinusoidal wave by an output signal from the PWM signal generation step, a drive control module of a drive control step for controlling the drive step, and a start or stop of drive A program having a first waveform changing module of a first waveform changing step for changing the shape of the drive current waveform by changing the duty ratio of the PWM for a certain period of time is stored.

In order to achieve the second object, a storage medium according to claim 21 of the present invention is the storage medium according to claim 20, wherein the program is executed at the time of starting or stopping the driving according to the driving speed. A second waveform changing module of a second waveform changing step of changing the shape of the driving current waveform by changing the duty ratio and the driving speed of the PWM is characterized in that the module has a second waveform changing module.

In order to achieve the second object, the storage medium according to claim 22 of the present invention is the storage medium according to claim 20, wherein the program is executed at the time of starting or stopping the driving according to the driving speed. It is characterized by having a period changing module of a period changing step of changing a period for changing the shape of the drive current waveform by changing the duty ratio of the PWM.

In order to achieve the second object, the storage medium according to claim 23 of the present invention is the storage medium according to claim 20, wherein the program starts or stops driving according to a driving phase position. A third waveform changing module of a third waveform changing step of changing the shape of the drive current waveform by sometimes changing the duty ratio of the PWM.

In order to achieve the second object, a storage medium according to a twenty-fourth aspect of the present invention includes a drive module having a drive step for driving a pulse motor with a substantially sinusoidal wave, and a drive control step for controlling the drive step. And a waveform changing step of changing the shape of the drive current waveform by changing the drive period and the PWM duty ratio and the drive speed at the start or stop of the drive according to the drive speed or the drive start and stop phases. A program having a waveform changing module is stored.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(First Embodiment) First, the first embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing a configuration of the pulse motor control device according to the first embodiment of the present invention. In FIG. 1, 1 and 2
Is a driver circuit, 3 and 4 are motor windings of a two-phase pulse motor 5, 5 is a two-phase pulse motor, 6 is a magnet of the two-phase pulse motor 5, and 7 is a microcomputer (hereinafter referred to as a microcomputer) for controlling the two-phase pulse motor 5. , Described as microcomputer)
A PWM (pulse width modulation) unit 7a for outputting a pulse signal (E, F) capable of setting a frequency and a duty ratio, a programmable timer unit 7b,
Output ports (A, B) capable of outputting “H (high)” and “L (low)” signals, and an RO storing data such as the driving speed of the two-phase pulse motor 5 and the duty ratio of PWM.
M (read only memory) 7c.

FIG. 2 is a block diagram showing the internal configuration of the driver circuits 1 and 2. In FIG. 2, 8 and 9 are PNP
Transistors 10 and 11 are NPN transistors, 1
2, 13, 14, 15 are diodes, 16, 17, 1,
8, 19 are resistors, 20, 21 are AND gates, 22 is N
OT gate. In FIG. 2, when the input terminal EN1 is at the “H” level and the input IN1 is at the “L” level, the transistors (hereinafter referred to as Tr) 8 and Tr11 are turned on (ON), and the transistors Tr9 and Tr10 are turned off (O
FF) state. Therefore, a current flows through the motor winding 3 from the output terminal OUT1 to the output terminal OUT2.
When the input terminal EN1 is at “H” level and the input terminal IN1 is at “L” level, Tr9 and Tr10 are turned on, and Tr8 and Tr11 are turned off. Therefore, the motor winding 3 is connected to the output terminal O2 from the output terminal OUT2.
A current flows in the direction of UT1. Also, the input terminal EN1
Is at the "L" level, Tr8 to Tr11 are in the OFF state regardless of the input level of the input terminal IN1, and the output terminal OUT1 to the output terminal OUT2 are in the high impedance state. FIG. 3 is a diagram showing the relationship between these inputs and outputs. The input terminal IN2, the input terminal EN2, and the output terminal O
The same applies to UT3 and output terminal OUT4. Also, the PWM unit 7a is sent from the microcomputer 7 to the driver circuits 1 and 2.
The output signal from the output terminal E is input to the input terminal IN1 of the driver circuit 1, and the output signal from the output terminal F of the PWM unit 7a is input to the input terminal IN2 of the driver circuit 2. The input terminal EN1 of the driver circuit 1 and the input terminal EN2 of the driver circuit 2 are connected to output ports A and B of the microcomputer 7 as shown in FIG.
“H” and “L” may be controlled, but the “H” level may be fixed without connecting to the microcomputer 7. next,
A method of controlling the motor winding current based on output signals from the output terminals E and F of the PWM unit 7a will be described. The microcomputer 7 shown in FIG. 1 inputs output signals from the output terminals E and F of the PWM unit 7a to the driver circuits 1 and 2 at a constant frequency fp. The motor windings 3 and 4 are driven by the above logic based on the PWM “H” and “L”. However, since the frequency fp is high, the motor windings 3 and 4 are affected by the inductance of the motor windings 3 and 4. Flows a current corresponding to the duty ratio as shown in FIG. FIG. 4A shows the relationship between the output signal from the output terminal E of the PWM unit 7a and time, and FIG. 4B shows the relationship between the winding current and time. Therefore, in order to perform a sine wave drive that is considered to have small vibration and noise, the change in the PWM duty ratio may be made substantially sinusoidal. In order to drive the motor more efficiently, the sine wave P to change the amplitude according to the rotation speed
What is necessary is just to adjust the change of the WM duty ratio. This duty ratio adjustment method will be described below with reference to FIG. FIG.
(A) shows the basic duty ratio data (Dn) with the maximum value ＄ FF and the minimum value 、 00, and FIG. 5B shows the maximum value ＄ F
F, duty ratio data (Dn) at the start and stop of driving with the minimum value of $ 00 are shown. Basic duty ratio data (Dn) with the maximum value ＄ FF and the minimum value ＄ 00 shown in FIG. 5A are stored in the ROM 7c of FIG. The duty ratio data is obtained, for example, by dividing one cycle of a sine wave signal into 64 parts. 0 to 63 in the upper row are the addresses of the ROM 7c attached for convenience, and the numerical values in the lower row are the duty ratio data stored in each address. The duty ratio data is sequentially read out by a timer interrupt of the microcomputer 7 and is set as a PWM duty ratio. By manipulating the timer interruption time (Tt),
The rotation speed of the pulse motor 5 can be adjusted. The output terminal E of the PWM unit 7a and the output terminal F of the PWM unit 7a are shifted from each other by 90 in the read ROM address so as to have a 90 deg phase shift. Then, when stopping the driving of the pulse motor 5, the output from the output terminals E and F of the PWM unit 7a may be stopped.
FIG. 6 is a flowchart showing an operation flow of the microcomputer 7 when starting and stopping the driving of the pulse motor 5 for carrying out the present invention. In step S601 in the figure, the speed (Vt) to be driven and the number of pulses a are set based on external information. This only needs to be able to input the driving speed and the number of pulses to the microcomputer 7 such as an external switch and communication. Here, b is set as a = b. Next, step S6
In 02, a timer interruption time Tt according to the driving speed is set. This is short if the driving speed is fast, and long if the driving speed is slow.

Next, in step S603, the process waits until the next drive information from the outside comes, and when drive information comes, the process returns to step S601. Thus, the pulse motor 5 is driven while repeating the processing operation of FIG. FIG. 7 is a flowchart showing an operation flow in the interrupt processing routine for controlling the output of the PWM unit 7a for actually driving. In step S701 of the figure, it is determined whether the number of drive pulses a set in the main routine of FIG. 6 is 0 or not. If the number of drive pulses a is 0, the pulse motor 5 is not driven.
After the output from the output terminals E and F of the WM unit 7a is stopped and the driving of the pulse motor 5 is stopped, this processing operation ends. If the number of drive pulses a is not 0, the duty ratio of the counter A (for example, 0 to 63) indicating the phase state of the pulse motor 5 at that time is obtained from the basic duty ratio data of FIG. Is read.
Next, it is determined in step S704 whether or not the counter A ≠ 63. If the counter A ≠ 63, the counter A is incremented in step S705, and the flow advances to step S707.
If the counter A is not equal to 63, the counter A is set to 0 in step S706, and the process proceeds to step S707. With this counter A, the current phase position within one cycle of a sine wave divided into 64 can be determined. In step S707, it is determined whether or not the counter A is a multiple of eight. A multiple of 8 of one cycle divided into 64 is one pulse, and one cycle is eight pulses. Therefore, if it is not a multiple of 8 in step S707, it is in the middle of movement for one pulse, and thus this processing operation is terminated as it is. Step S7
If the counter A is a multiple of 8 at 07, step S7
In step 08, it is determined whether or not b = a. And b = a
If so, it is known that it is the drive start timing, and the process proceeds to step S710. If b = a is not satisfied in step S708, it is determined in step S709 whether b = 1. If b = 1, the operation is stopped in one more pulse, so that it is determined that the stop preparation timing is reached, and the process proceeds to step S710. In this step S710, the interruption time of the timer set in step S602 in FIG. 6 is set to twice the time Tt, and the process proceeds to step S714. As a result, at the start of driving and during the preparation for stopping, the driving speed is reduced by the time corresponding to one pulse. FIG. 8 shows the waveform at this time.
The horizontal axis indicates time, and the vertical axis indicates current. However, in FIG. 8, the above operation is performed only at the time of stop. In FIG. 8, X is a waveform when the speed is not slowed down when stopped, and Y is a waveform when the speed is slowed down when stopped as in the operation of FIG. Returning to FIG. 7 again, if b = 1 in step S709, step S71
It is determined whether or not b ≠ 0 at 1; if b ≠ 0, step S
At 712, the timer interruption time Tt set at the step 602 of FIG. 6 is set (see FIG. 8).
Proceed to step S714. Also, the step S711
If b ≠ 0 is not satisfied in step S713, the PWM
After the output from the output terminals E and F of the unit 7a is stopped and the driving of the pulse motor 5 is stopped, the processing operation ends. In step S714, 1 is subtracted from b, and this processing operation ends. FIG. 9 is a diagram showing a waveform state when eight pulses are driven at a driving speed of 600 pps according to the operation flow of FIG. FIG. 3A shows a conventional driving method, and FIG. 3B shows a driving method of the present invention. FIG. 7 above
In step S710, the timer interrupt time is set so that the speed is changed to the same speed when the pulse motor 5 starts driving and when the pulse motor 5 stops, but the speed differs between when the pulse motor 5 starts driving and when the pulse motor 5 stops. The timer interrupt time may be set as described above. In FIG. 7, the number of divisions of the duty ratio data for determining the shape of the drive current waveform is set to 64. This means that the drive current waveform becomes closer to a sine wave when the number of divisions is larger. It does not have to be a division. Further, in FIG. 7 described above, the speed is changed both when the driving of the pulse motor 5 is started and when the pulse motor 5 is stopped, but the speed may be changed only by either one of them. As described in detail above, the drive speed is accelerated or decelerated in units of one pulse during the interruption of the microcomputer 7 at the start and stop of the pulse motor 5, so that the drive of the pulse motor 5 is started and stopped. The drive current waveform becomes smooth, and the noise of the pulse motor 5 can be reduced. Further, in FIG. 7, the speed between one pulse at the time of starting and stopping the driving of the pulse motor 5 is changed as shown by the Y waveform in FIG. 8, but as shown by the Z waveform in FIG. The drive current waveform can be made smoother by gradually delaying and decelerating the interruption time of the timer between one pulse depending on the phase position.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. Note that the basic configuration of the pulse motor control device according to the present embodiment is the same as that in FIGS. 1 and 2 in the first embodiment described above, and therefore will be described with reference to both drawings.

In the above-described first embodiment, the method of accelerating or decelerating by one pulse as a distance at the time of starting or stopping the driving of the pulse motor 5 has been described. Since the acceleration or deceleration distance for one pulse is too short, the present embodiment is designed to accelerate or decelerate for several pulses according to the speed.

FIG. 10 is a flowchart showing an interrupt operation flow in the microcomputer 7 in the pulse motor control device according to the present embodiment. The main routine is the same as FIG. 6 in the first embodiment. The processing in the interrupt will be described below.

In FIG. 10, in step S1001, it is determined whether the number of drive pulses a = 0 or not.
If so, in step S1002, the output from the output terminals E and F of the PWM unit 7a is stopped to stop the driving of the pulse motor 5, and then this processing operation is ended. If the number of drive pulses a is not 0, step S100
In step 3, the distance (pulse conversion) c to be accelerated or decelerated according to the driving speed (Vt) is set. This distance c increases as the driving speed (Vt) increases, and decreases as the driving speed (Vt) decreases. This value may be different between when the pulse motor 5 starts and when it stops. If they are different, a start distance c1 and a stop distance c2 are set.

Next, in step S1004, the duty ratio of the counter A (for example, 0 to 63) indicating the phase state of the pulse motor 5 at that time is read from the basic duty ratio data of FIG. Next, it is determined in step S1005 whether or not the counter A ≠ 63. If the counter A ≠ 63, the counter A is incremented in step S1006, and the process proceeds to step S1008. Also, counter A
If not $ 63, the counter A is set to 0 in step S1007, and the flow advances to step S1008. With this counter A, the current phase position within one cycle of the sine wave divided into 64 can be determined.

In step S1008, it is determined whether or not the counter A is a multiple of eight. A multiple of 8 of one cycle divided into 64 is one pulse, and one cycle is eight pulses. Therefore, if the counter A is not a multiple of 8 in step S1008, it is in the process of moving for one pulse, and thus the processing operation is terminated.

If it is determined in step S1008 that the counter A is a multiple of 8, the flow advances to step S1009 to determine whether b ≧ ac. If c1 is set for the start of driving in step S1003, b is compared with a-c1. If b ≧ ac in step S1009, it is understood that the current time is within the acceleration distance of the drive start timing, and the process proceeds to step S1011. The step S
If b ≧ ac is not satisfied in step 1009, step S1
At 010, it is determined whether or not b ≦ c. Then, if c2 is set for stopping at step S1003, b is compared with c2. If b ≦ c in step S1010, it is determined that it is the stop preparation timing because the stop is performed at the end of the c pulse, and the process proceeds to step S1011. In this step S1011,
The interruption time of the timer set in step S602 in FIG. 6 is set to twice Tt, and step S1
Go to 015. As a result, at the time of driving start and at the time of preparation for stopping, the driving speed is reduced by the time corresponding to the c pulse.

FIG. 11 shows the waveform at this time.
In the figure, the horizontal axis represents time, and the vertical axis represents current. However, in FIG. 11, the above operation is performed only at the time of stop. In FIG. 11, X is a waveform when the delay is not made at the time of stopping, and Y is the first waveform described above.
As in the operation of FIG.
This is a waveform when the speed is reduced only between pulses. Furthermore,
In FIG. 11, Z changes the deceleration distance (number of pulses) according to the speed as in the operation of FIG.
This is a waveform when deceleration for a pulse is being performed.

Returning again to FIG. 10, step S10
If it is not b ≦ c in 10, it is determined in step S1012 whether or not b ≠ 0.
In step 013, the timer interruption time Tt set in step S602 in FIG.
), And proceed to step S1015. This step S10
At 15, after subtracting 1 from b, this processing operation ends.
If b ≠ 0 is not satisfied in step S1012, the output from the output terminals E and F of the PWM unit 7a is stopped in step S1014, and the drive of the pulse motor 5 is stopped.

In step S1011 of FIG.
Although the timer interrupt is set so as to change to the same speed when the motor drive starts and when the motor stops, the timer interrupt may be set to be different between the start and the stop. Also, in FIG. 10, the number of divisions of the duty ratio data for determining the shape of the drive current waveform is set to 64, which indicates that the drive current waveform becomes closer to a sine wave as the number of divisions increases.
It does not have to be 64 divisions. Further, in FIG. 10, the speed is changed at both the start and the stop of the motor driving, but the speed may be changed at only one of them.

As described above, during the interruption of the microcomputer 7, the drive speed is accelerated or decelerated at the start and stop of the drive in units of several pulses in accordance with the drive speed determined in the main routine. The drive current waveform at the time of driving start and stop at the time of high-speed driving becomes smooth,
The noise of the pulse motor 5 can be reduced.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. Note that the basic configuration of the pulse motor control device according to the present embodiment is the same as that in FIGS. 1 and 2 in the first embodiment described above, and therefore will be described with reference to both drawings.

In the first and second embodiments, the method of accelerating or decelerating the pulse motor 5 for a certain period at the time of starting and stopping the driving of the pulse motor 5 has been described. There is a phase in which the driving can be started and stopped smoothly without changing the speed depending on the driving phase position.
There are also phases where the speed has to be changed significantly. Therefore, in the present embodiment, the speed is changed according to the drive phase at the time of starting and at the time of stopping.

FIG. 12 is a flowchart showing an interrupt operation flow in the microcomputer 7 in the pulse motor control device according to the present embodiment. The main routine is the same as that in FIG. 6 in the first embodiment.

The processing operation in the interrupt will be described below.

It is determined in step S1201 in FIG. 12 whether the number of drive pulses a = 0 or not. If the number of drive pulses a = 0, the output from the output terminals E and F of the PWM unit 7a is stopped in step S1202 to change the pulse. After the driving of the motor is stopped, this processing operation ends. If the number of drive pulses a is not 0 in step S1201, a counter A (for example, 0 to 0) indicating the phase state of the pulse motor 5 at that time is obtained in step S1403 from the basic duty ratio data shown in FIG. The duty ratio in step 63) is read. Next, in step S1204, the counter A # 6
It is determined whether it is 3 or not. If the counter A is not equal to 63, the counter A is incremented in step S1205, and then the process proceeds to step S1207. Also, the step S1204
If the counter A is not 63 at step S120
After setting the counter A to 0 in step 6, the process proceeds to step S1207. With this counter A, the current phase position within one cycle of the sine wave divided into 64 can be determined.

In step S1207, the counter A is set to 8
Judge whether it is a multiple of. 8 out of 64 divided 1 cycle
A multiple of is one pulse, and one cycle is eight pulses. Therefore, if the counter A is not a multiple of 8 in step S1207, it is in the process of moving for one pulse, and thus the present processing operation ends. If it is determined in step S1207 that the counter A is a multiple of 8, the flow advances to step S1208 to determine whether b = a. Then, if b = a, it is found that it is within the acceleration distance of the drive start timing, and the process proceeds to step S1210. If it is not b = a in step S1208, it is determined in step S1209 whether b = 1. If b = 1, the operation is stopped in one more pulse, so that it is determined that the stop preparation timing is reached, and step S12 is performed.
Proceed to 10.

In this step S1210, it is determined whether or not the phase counter A is 8, 16, 40 or 48. FIG. 17 shows the relationship between the value of the phase counter A and the phase. In step S1210, A = 8, 16,
If it is any of 40 and 48, since the slope is the steepest in the sine wave waveform, the flow advances to step S1211 to set the timer interrupt to four times Tr and set it to 1/4 of the normal speed to obtain a sufficient waveform. Then, the process proceeds to step S1212.

FIG. 13 shows the waveform at this time, in which the horizontal axis represents time and the vertical axis represents current. However, in FIG. 13, the above operation is performed only at the time of stop. In FIG. 13, X is a waveform when the speed is not delayed when stopped, and Y is a waveform when the speed is reduced for one pulse during the stop as in the operation of FIG.

In step S1210, A = 8,
If it is not any one of 16, 40, and 48 (the position of the phase is different), it is determined whether the phase counter A is 0 or 32 in step S1213. If the phase counter A is either 0 or 32, step S12
At 14, the timer interrupt is set to twice the Tr, to half the normal speed, and the waveform is gently sloped.
Proceed to step S1212.

FIG. 14 shows the waveform at this time, in which the horizontal axis represents time and the vertical axis represents current. However, in FIG. 14, the above operation is performed only at the time of stop. In FIG. 14, X is a waveform when the speed is not delayed when stopped, and Y is a waveform when the speed is reduced by one pulse during the stop as in the operation of FIG.

If the phase counter A is not 0 or 32 (different phases) in step S1213, that is, if A = 24 or 56, the sine wave waveform is a sufficiently gentle place, so Since no change is required, the main routine shown in FIG.
After setting the normal timer interruption time Tr set in step S602, the process proceeds to step S1212.

FIG. 15 shows the waveform at this time. In FIG. 15, the horizontal axis represents time, and the vertical axis represents current. However, in FIG. 15, the above operation is performed only at the time of stop, and there is no change in speed at the time of stop.

On the other hand, in step S1209, b
If it is not = 1, it is determined whether or not b で 0 in step S1215. If b ≠ 0, the timer interruption time Tt set in step S602 in FIG. 6 is set in step S1216. If b ≠ 0 is not satisfied in step S1215, the output from the output terminals E and F of the PWM unit 7a is stopped in step S1417, the driving of the motor is stopped, and this processing operation ends. Also,
In this step S1212, after subtracting 1 from b, this processing operation ends.

FIG. 16 is a diagram showing a waveform when eight pulses are driven at a driving speed of 600 pps in accordance with the operation flow of FIG. FIG. 3A shows a conventional driving method, and FIG. 3B shows a driving method according to the present embodiment.

Steps 1211, 1212, 1 in FIG.
In 215, the timer interrupt is set so that the speed is changed to the same speed when the pulse motor 5 starts and stops, but the speed is set to be different between when the pulse motor 5 starts and stops. May be. FIG.
Has set the number of divisions of the duty ratio data for determining the shape of the drive current waveform to 64, which means that the drive current waveform becomes closer to a sine wave when the number of divisions is larger.
It does not have to be a division. Also, in FIG.
Speed was changed both at the start and stop of the drive,
The speed may be changed by only one of them.

As described above, during the interruption of the microcomputer 7, the driving speed is accelerated or decelerated at the start or stop of the driving only at a necessary phase according to the driving phase position, thereby performing high-speed driving. In this case, the drive current waveforms at the start and stop of the drive become smoother, and the noise of the pulse motor 5 can be reduced.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. 18 and FIG. Note that the basic configuration of the pulse motor control device according to the present embodiment is the same as that in FIGS. 1 and 2 in the first embodiment described above, and therefore will be described with reference to both drawings.

In the first and second embodiments described above,
At the time of starting and stopping the driving of the pulse motor 5, the method of changing the timer interrupt time by a certain pulse to accelerate or decelerate is exemplified. In the case of this method, as shown in FIGS. Reaching the target position when the vehicle is not decelerated is delayed as indicated by ',' due to the deceleration. Therefore, in the present embodiment, the timer interrupt time is changed to reduce the driving speed, and the driving is started. The drive current waveform at the time of stop and stop,
It is not a method to reduce the noise of the
By changing the duty ratio stored in c, changing the shape of the drive current waveform, smoothing the drive current waveform at the start and stop of the drive, and reducing the noise of the pulse motor 5 without changing the drive speed. Is to be reduced.

FIG. 18 is a flowchart showing an interrupt operation flow in the microcomputer 7 in the pulse motor control device according to the present embodiment, and the main routine is the same as that in FIG. 6 in the first embodiment. The processing in the interrupt will be described below.

It is determined in step S1801 in FIG. 18 whether the number of drive pulses a = 0 or not. If the number of drive pulses a = 0, output from the output terminals E and F of the PWM unit 7a is stopped in step S1802. After the driving of the pulse motor 5 is stopped, this processing operation is terminated. If the number of drive pulses a is not 0 in step S1801, it is determined in step S1803 whether or not the counter A ≠ 63. If the counter A ≠ 63, the process proceeds to step S1804.
In step S1805, the counter A is incremented.
Proceed to. If the counter A is not equal to 63 in step S1803, the counter A is determined in step S1805.
Is set to 0, and the process proceeds to step S1805. With this counter A, the current phase position within one cycle of the sine wave divided into 64 can be determined.

From the basic duty ratio data shown in FIG. 5A, the duty ratio of the counter A (for example, 0 to 63) indicating the phase state of the pulse motor 5 at that time is shown in FIG.
0 is read in step S1004. Next, step S
In step 1005, it is determined whether or not the counter A ≠ 63. If the counter A ≠ 63, the counter A is incremented in step S1006. If the counter A ≠ 63, the counter A is set to 0 in step S1007. With this counter A, the current phase position within one cycle of the sine wave divided into 64 can be determined.

Returning to FIG. 18, in step S1805, it is determined whether or not b = a. If b = a, it is determined that the drive start timing is reached, and step S1806 is performed.
Proceed to. In step S1805, b = a
If not, it is determined in step S1810 whether or not b = 1. If b = 1, the operation is stopped by one pulse, so that it is determined that it is the stop preparation timing, and the process proceeds to step S1806. In this step S1806, a counter A indicating the phase state of the pulse motor 5 at that time is obtained from the data table shown in FIG. 5B stored in the microcomputer 7 as the duty ratio data for driving start and stop. After reading the duty ratio (for example, 0 to 63), the process proceeds to step S1807.

On the other hand, in step S1810, b
If it is not = 1, it is determined in step S1811 whether b ≠ 0. If b で あ れ ば 0, the data shown in FIG. 5A stored in the microcomputer 7 as normal duty ratio data in step S1812. From the table, a counter A (for example, 0 to 6) indicating the phase state of the pulse motor 5 at that time is displayed.
Read the duty ratio in 3) (-in FIG. 19),
Proceed to step S1807. Step S18
If b ≠ 0 is not satisfied in 11, the output from the output terminals E and F of the PWM unit 7 a is stopped in 1813, the driving of the pulse motor 5 is stopped, and the processing operation is terminated.

In step S1807, the counter A is set to 8
Judge whether it is a multiple of. 8 out of 64 divided 1 cycle
A multiple of is one pulse, and one cycle is eight pulses. Therefore, if the counter A is not a multiple of 8 in step S1807, it is in the process of moving for one pulse, and thus this processing operation is terminated. If the counter A is a multiple of 8 in the step S1807,
In step S1808, b = b-1 is calculated, and the driving pulse a set in step S601 in FIG.
After the number of pulses to be driven is set to b, the processing operation ends.

FIG. 19 shows the waveform at this time. In FIG. 19, the horizontal axis represents time, and the vertical axis represents current. However, in FIG. 19, the above operation is performed only at the time of stop. In FIG. 19, X is the waveform when the shape of the drive current waveform is not changed at the time of stop, and Z is the shape of the drive current waveform for only one pulse at the time of stop, as in the operation of FIG. 18 of the present embodiment. Is a waveform when is changed.

In step S1806 in FIG. 18,
Although the duty ratio data is read so as to change to the same waveform at the start and stop of the driving of the pulse motor 5, the waveform is different between the start and the stop of the driving of the pulse motor 5. The duty ratio data for driving start and stop may be stored in the ROM 7c of the microcomputer 7. In FIG. 18, the number of divisions of the duty ratio data for determining the shape of the drive current waveform is set to 64.
If the number of divisions is large, it indicates that the drive current waveform is closer to a sine wave. In FIG. 18, the waveform is changed both when the driving of the pulse motor 5 is started and when it is stopped. However, the waveform may be changed by only one of them.

As described above, during the interruption of the microcomputer 7, the shape of the driving current waveform is changed between when the driving of the pulse motor 5 is started and when it is stopped, and the driving current when the driving of the pulse motor 5 is started and when it is stopped is changed. By smoothing the waveform, the pulse motor 5 can be driven without changing the drive time of the pulse motor 5.
Noise can be reduced.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described.
An embodiment will be described. In the above-described fourth embodiment, a method of changing the shape of the drive current waveform at the time of starting and stopping the driving of the pulse motor 5 to smooth the driving current waveform at the time of starting and stopping the driving of the pulse motor 5 is described. As illustrated, when driving at high speed, changing the shape of the drive current waveform alone does not make the waveform smooth. Therefore, in the present embodiment, when the operation of the above-described first embodiment is performed, the shape of the drive current waveform is changed at the time of starting and stopping the driving, and the driving speed is reduced, so that a smoother operation is achieved. This makes it possible to realize noiseless driving.

FIG. 19 shows the waveform at this time.
In the figure, the horizontal axis represents time, and the vertical axis represents current. However, in FIG. 19, the above operation is performed only at the time of stop. In FIG. 19, Y is a waveform when the operation of the first embodiment is performed and the driving speed is reduced. Also,
In FIG. 19, W is a waveform when the shape and speed of the drive current waveform are changed only for one pulse at the time of stop, as in the operation of the fifth embodiment.

(Sixth Embodiment) Next, the sixth embodiment of the present invention will be described.
An embodiment will be described. In the above-described fourth embodiment, the method of changing the shape of the drive current waveform at the time of starting and stopping the driving of the pulse motor 5 and smoothing the driving current waveform at the time of starting and stopping the driving is exemplified. When driving at high speed, changing the shape of the drive current waveform alone does not make the waveform smooth. Therefore, the operation of the second embodiment is performed in the fourth embodiment, and the shape of the drive current waveform is changed at the start and stop of the drive only for a period corresponding to the drive speed, so that smoother noise is eliminated. Driving can be realized.

(Seventh Embodiment) Next, a seventh embodiment of the present invention will be described.
An embodiment will be described. In the above-described fourth embodiment, the method of changing the shape of the drive current waveform at the time of starting and stopping the driving of the pulse motor 5 and smoothing the driving current waveform at the time of starting and stopping the driving is exemplified. At the time of high-speed driving, changing the shape of the driving current waveform alone does not make the waveform smooth. Therefore, the fifth and sixth embodiments have been described.
However, in the fifth embodiment, the driving time is changed,
It takes much time to change the drive speed.
Further, in the sixth embodiment, the drive torque is reduced by the amount by which the shape of the drive current waveform is changed and smoothed. Therefore, when the operation of the fourth embodiment is performed only with the necessary phase, the drive current waveform can be made smoother by changing the torque only to the minimum.

Therefore, when the operation of the third embodiment is performed in the fourth embodiment, the shape of the drive current waveform is changed at the start and stop of the drive according to the drive phase position, thereby providing a smoother operation. Driving without noise can be realized.

(Eighth Embodiment) Next, an eighth embodiment of the present invention will be described.
The embodiment will be described with reference to FIG. FIG.
FIG. 21 is a block diagram illustrating a configuration of an imaging device such as a video camera having a pulse motor control device according to an eighth embodiment of the present invention. In the figure, reference numeral 100 denotes an inner focus type lens system, and a fixed front lens group 1
01, a second lens group for performing zooming (hereinafter, referred to as a zooming lens) 102, an aperture 103, a fixed third lens group 104, and a fourth lens having both a competing function and a focusing function A group (hereinafter, referred to as a focus competition lens) 105 is provided. The image light transmitted through the lens system 100 forms an image on the surface of an image sensor (hereinafter, referred to as a CCD) 106 and is converted into a video signal by photoelectric conversion. Reference numeral 107 denotes an amplifier or impedance converter, and reference numeral 108 denotes a camera signal processing circuit. The video signal processed here is amplified to a specified level by an amplifier 109, processed by an LCD display circuit 110, and then converted to an LCD (liquid crystal display). At 111, the captured image is displayed.

On the other hand, the video signal amplified by the amplifier 107 is sent to an aperture control circuit 112 and an AF (auto focus) evaluation value processing circuit 114. The iris control circuit 112 controls the IG driver 113 according to the video signal input level.
By driving the IG meter 114 and the aperture 103
Is controlled to adjust the amount of light.

The AF evaluation value processing circuit 115 performs a process of extracting a high-frequency component of a luminance signal in the distance measurement frame according to the gate signal from the distance measurement frame generation circuit 117. 116 is A
An F microcomputer (hereinafter, referred to as an AF microcomputer) performs lens drive control and distance measurement frame control for changing a distance measurement area in accordance with the AF evaluation signal intensity. Reference numeral 116 communicates with a system control microcomputer (hereinafter, referred to as a syscon) 122, and the syscon 122 has an A (analog) / D (digital)
Information of a zoom switch (SW) unit 123 (a unitized zoom SW that outputs a voltage corresponding to the rotation angle of the operation member. A variable speed zoom is performed according to the output voltage) is read by conversion or the like. , AF microcomputer 1
The zoom operation information such as the zoom direction and the focal length at the time of zooming controlled by the zoom lens 16 is exchanged with each other.

Reference numerals 118 and 120 denote the AF microcomputer 1
Drivers 119 and 121 for outputting driving energy to the lens driving motors 119 and 121 according to the driving commands of the variable power lens 102 and the focus compensating lens 105 output from the zoom lens 102 and the focus compensating lens 105 respectively. It is a motor for driving.

Next, the lens driving motors 119 and 12
Assuming that 1 is a pulse motor, a driving method of the motor will be described.

The AF microcomputer 116 determines the driving speeds of the variable power lens motor 119 and the focus compensating lens motor 121 by program processing, and outputs a variable frequency lens driver for driving the variable power lens motor 119 as a rotation frequency signal of each pulse motor. 118, focus competition lens driver 1 for driving focus competition lens motor 121
Send to 20. Further, a drive / stop command and a rotation direction command for both motors 119 and 121 are sent to the respective drivers 118 and 120. The drive / stop signal and the rotation direction signal are
The zoom lens motor 119 mainly includes a zoom switch
In accordance with the state of the unit 123, the focus compensation lens motor 119 responds to a drive command determined by processing in the microcomputer 116 during AF and zoom.
The motor drivers 118 and 120 set the phases of the four motor excitation phases to forward rotation and reverse rotation in accordance with the rotation direction signal, and apply the applied voltages of the four motor excitation phases (in accordance with the received rotation frequency signal). Or while changing the current), the output to the motors 119 and 121 is turned on / off in response to the drive / stop command while controlling the rotation direction and rotation frequency of the motors 119 and 121. (OFF) is controlled.

FIG. 21 is a flowchart showing a control flow in the pulse motor control device according to the present embodiment, which is processed in the AF microcomputer 116.

In FIG. 21, step S2101 is an initial setting routine, which is a RAM in the AF microcomputer 116.
And processing of various ports. Step S2102 is a mutual communication routine with the system controller 122. Here, information of the zoom SW unit 123 and magnification operation information such as the position of the magnification lens 102 are exchanged. Step S
Reference numeral 2103 denotes an AF processing routine, which processes a sharpness signal of the AF evaluation signal using a signal obtained from the AF evaluation value processing circuit 115, and performs automatic focus adjustment processing according to a change in the evaluation signal. Step S2104 is a zoom processing routine, which is a processing routine of a competition operation for maintaining focus during the magnification operation, and calculates a driving direction and a driving speed of the focus competition lens 105 for tracing a cam track. . Step S2105 is a drive direction and speed selection routine. Which one of the drive direction and the drive speed of the variable power lens 102 and the focus competition lens 105 is to be used, which is calculated according to the AF operation, the variable power operation, and the like? Is selected, and the lens is not driven to the tele side from the tele end, the wide side from the wide end, the near side from the close end, and the infinite side from the infinite end provided in software so as not to hit the mechanical ends of the lenses 102 and 105. This is a routine for setting. In step S2106, the motor drivers 118 and 120 are driven according to the drive direction and drive speed information for zoom and focus determined in step S2105.
To control the driving / stopping of the lenses 102 and 15. After the end of the processing in step S2106,
The process returns to step S2102.

The series of processes shown in FIG. 21 are executed in synchronization with the vertical synchronization period (the process waits until the next vertical synchronization signal comes in the process of step S21).

Step S2105 in FIG. 21 corresponds to FIG.
In the operation of, the interrupt processing as shown in FIGS. 7, 10, 12, and 18 is performed by the drive speed and the drive pulse set here, and the drive and the drive are performed as in the focus competition lens 105. Even when the user makes a motion that is disadvantageous to noise that repeatedly stops, the noise can be reduced.

(Ninth Embodiment) Next, a storage medium used in the pulse motor control method and apparatus of the present invention will be described.
This will be described with reference to FIGS.

A storage medium for storing a control program for controlling the first pulse motor control device of the present invention includes:
As shown in FIG. 22, at least the “drive module”,
What is necessary is just to store the program code of each module of a "drive control module", a "first waveform change module", a "second waveform change module", and a "time change module".

Here, the "drive module" is a program module for driving the pulse motor in a substantially sinusoidal manner. The “drive control module” is a program module for controlling a drive step. Also,
The “first waveform change module” is a program module for changing the shape of the drive current waveform by changing the drive speed for a certain period at the start or stop of the drive. The “second waveform change module” is a program module for changing the shape of the drive current waveform by changing the drive speed at the start or stop of the drive according to the drive phase position. Further, the "time change module" is a program module for changing the drive speed at the start or stop of the drive according to the drive speed and changing the time for changing the shape of the drive current waveform.

As shown in FIG. 23, at least the first and second "PWM signal generation modules" are stored in a storage medium for storing a control program for controlling the second pulse motor control device of the present invention. , "Drive module",
What is necessary is just to store the program code of each module of a "drive control module", a "1st waveform change module", a "2nd waveform change module", a "3rd waveform change module", and a "period change module".

Here, the first and second "PWM signal generation modules" are program modules for generating a PWM signal whose duty ratio can be set. Further, the “drive module” is a program module for driving the pulse motor with a substantially sinusoidal wave based on an output signal from the PWM signal generation step. The “drive control module” is a program module for controlling a drive step. Also, "first waveform changing module"
Is a program module for changing the shape of the drive current waveform by changing the duty ratio of the PWM for a certain period at the start or stop of driving. The “second waveform change module” is a program module for changing the shape of the drive current waveform by changing the drive speed.
The “third waveform change module” is a program module for changing the shape of the drive current waveform by changing the drive period, the duty ratio of PWM, and the drive speed at the start or stop of the drive according to the drive phase position. is there.
The “period change module” is a program module for changing the shape of the drive current waveform by changing the PWM duty ratio at the start or stop of driving according to the drive speed.

Further, as shown in FIG. 24, at least a “drive module”, a “drive control module” and a “drive control module” are stored in a storage medium for storing a control program for controlling the third pulse motor control device of the present invention. What is necessary is just to store the program code of each module of "waveform change module".

Here, the "drive module" is a program module for driving the pulse motor in a substantially sinusoidal manner. The “drive control module” is a program module for controlling a drive step. Furthermore,
The "waveform change module" is a program for changing the shape of the drive current waveform by changing the drive period, the duty ratio of PWM, and the drive speed at the start or stop of the drive according to the drive speed or the drive start and stop phases. Module.

[0097]

As described above, according to the pulse motor control method and apparatus of the present invention, the following effects can be obtained.

1. When driving a sine wave pulse motor,
When the drive and stop are repeated, the drive current waveform at the start or stop of the drive is smoothed by reducing the drive speed for a certain period at the start or stop of the drive, and the drive current at the start or stop of the pulse motor is reduced. Noise can be reduced.

2. When driving a sine wave pulse motor,
When driving and stopping are repeated, when the driving is started or stopped, the driving current is slowed down by a period corresponding to the driving speed, so that the driving current waveform at the time of starting or stopping the driving becomes smoother and the driving current is stopped. Noise at the time of starting or stopping the driving of the pulse motor can be reduced.

3. When driving a sine wave pulse motor,
When driving and stopping are repeated, when the driving is started or stopped, the driving speed is reduced according to the driving phase position, so that only the driving current waveform at the time of starting or stopping driving is not smooth becomes smooth. Also, noise at the time of starting or stopping the driving of the pulse motor during high-speed driving can be reduced.

4. When driving a sine wave pulse motor,
When the drive and stop are repeated, the drive current waveform at the start or stop of the drive becomes smooth by changing the shape of the drive current waveform to be gentle for a certain period of time at the start or stop of the drive. , The noise at the start or stop of the driving of the pulse motor can be reduced.

5. When driving a sine wave pulse motor,
When driving and stopping are repeated, at the time of starting or stopping driving, the shape of the driving current waveform is changed so as to be gentle for a certain period of time, and the driving speed is also reduced, so that the driving current waveform at the time of starting or stopping driving is changed. It becomes smoother, and noise at the time of starting or stopping the driving of the pulse motor can be reduced.

6. When driving a sine wave pulse motor,
When the drive and stop are repeated, the drive current waveform at the start or stop of the drive is smoother by changing the shape of the drive current waveform during the start or stop of the drive so that the shape of the drive current waveform is gradual according to the drive speed. Thus, the noise at the time of starting or stopping the driving of the pulse motor can be reduced.

7. When driving a sine wave pulse motor,
When the drive and stop are repeated, the drive current waveform at the start or stop of the drive is not smooth by changing the shape of the drive current waveform to be gentle according to the drive phase position at the start or stop of the drive. Only the driving current waveform becomes smooth, and noise at the time of starting or stopping the driving of the pulse motor during high-speed driving can be reduced.

Further, according to the storage medium of the present invention, the pulse motor control device of the present invention can be controlled smoothly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a pulse motor control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of a driver circuit in the device.

FIG. 3 shows an input terminal EN of a driver circuit in the device.
FIG. 2 is a diagram illustrating a relationship between the input and the output of each of the transistors IN1, IN1, and each transistor Tr.

FIG. 4 is a diagram showing a state of an output of an output terminal E of a PWM unit and a winding current in the device.

FIG. 5 is a diagram showing duty ratio data stored in a ROM of a PWM unit in the same device.

FIG. 6 is a flowchart showing an operation flow of a microcomputer in the device.

FIG. 7 is a flowchart showing an interrupt operation flow in the microcomputer in the device.

FIG. 8 is a diagram showing a drive current waveform in the device.

FIG. 9 is a diagram showing a drive current waveform in the device.

FIG. 10 is a flowchart showing an interrupt operation flow in a microcomputer in the pulse motor control device according to the second embodiment of the present invention.

FIG. 11 is a diagram showing a drive current waveform in the device.

FIG. 12 is a flowchart showing an interrupt operation flow in the microcomputer in the pulse motor control device according to the third embodiment of the present invention.

FIG. 13 is a diagram showing a drive current waveform in the device.

FIG. 14 is a diagram showing a drive current waveform in the same device.

FIG. 15 is a diagram showing a drive current waveform in the same device.

FIG. 16 is a diagram showing a drive current waveform in the same device.

FIG. 17 is a diagram showing a relationship between a value of a phase counter and a phase in the same device.

FIG. 18 is a flowchart showing an interrupt operation flow in the microcomputer in the pulse motor control device according to the fourth embodiment of the present invention.

FIG. 19 is a diagram showing a drive current waveform in the same device.

FIG. 20 is a block diagram illustrating a configuration of an imaging device including a pulse motor control device according to an eighth embodiment of the present invention.

FIG. 21 is a flowchart showing an operation flow of an AF microcomputer in the same device.

FIG. 22 is a diagram showing a program module stored in a storage medium of the present invention.

FIG. 23 is a diagram showing a program module stored in the storage medium of the present invention.

FIG. 24 is a diagram showing a program module stored in a storage medium of the present invention.

FIG. 25 is a diagram showing a drive current waveform of a pulse motor.

[Explanation of symbols]

 1 Driver Circuit 2 Driver Circuit 3 Motor Winding 4 Motor Winding 5 Pulse Motor 6 Magnet 7 Microcomputer 7a PWM Unit 7b Timer Unit 7c ROM 8 Transistor 9 Transistor 10 Transistor 11 Transistor 12 Diode 13 Diode 14 Diode 15 Diode 16 Resistance 17 Resistance 18 Resistance 19 Resistance 20 AND gate 21 AND gate 22 NOT gate 101 Fixed first lens group 102 Second lens group (magnifying lens) 103 Aperture 104 Fixed third lens group 105 105 Fourth lens group ( Focus Compensation Lens) 106 CCD (Imaging Device) 107 Amplifier (AMP) 108 Camera Signal Processing Circuit 109 Amplifier (AMP) 110 LED Display Circuit 111 LED Reference Signs List 12 aperture control circuit 113 IG driver 114 IG meter 115 AF evaluation value processing circuit 116 AF microcomputer (AF microcomputer) 117 frame generation circuit 118 variable-magnification lens driver 119 variable-magnification lens motor 120 focus-compensation lens driver 121 focus-compensation lens motor 122 syscon (System controller) 123 Zoom switch (SW) unit

Claims (24)

[Claims] 1. A driving step for driving a pulse motor in a substantially sinusoidal wave, a driving control step for controlling the driving step, and changing a driving current waveform by changing a driving speed for a certain period when starting or stopping driving. And a waveform changing step. 2. The pulse motor according to claim 1, further comprising a time changing step of changing the drive speed at the start or stop of the drive according to the drive speed to change the time for changing the shape of the drive current waveform. Drive control method. 3. The pulse motor drive according to claim 1, further comprising a waveform changing step of changing the shape of the drive current waveform by changing the drive speed at the start or stop of the drive according to the drive phase position. Control method. 4. A step of generating at least two PWM signals capable of setting a duty ratio for generating a PWM (pulse width modulation) signal, and a driving step of driving a pulse motor with a substantially sine wave using an output signal from the PWM signal generating step. A drive control step for controlling the drive step;
A waveform changing step of changing the shape of the drive current waveform by changing the duty ratio of PWM for a certain period at the time of starting or stopping driving. 5. The method according to claim 4, further comprising the step of changing the shape of the drive current waveform by changing the PWM duty ratio and the drive speed when the drive is started or stopped according to the drive speed. Pulse motor drive control method. 6. The method according to claim 4, further comprising a period changing step of changing a period of changing a shape of the driving current waveform by changing a duty ratio of the PWM at the time of starting or stopping the driving according to the driving speed. The pulse motor drive control method described in the above. 7. The pulse according to claim 4, further comprising a waveform changing step of changing the shape of the driving current waveform by changing the duty ratio of the PWM at the time of starting or stopping the driving according to the driving phase position. Motor drive control method. 8. A driving step for driving the pulse motor in a substantially sinusoidal wave, a driving control step for controlling the driving step, and a driving period and a PWM for starting or stopping the driving according to the driving speed or the driving start and stop phases. And a waveform changing step of changing the shape of the drive current waveform by changing the duty ratio and the drive speed. 9. A pulse motor, driving means for driving the pulse motor with a substantially sinusoidal wave, driving control means for controlling the driving means, and driving current by changing the driving speed for a certain period at the start or stop of driving. A pulse motor drive control device comprising: a waveform changing means for changing a shape of a waveform. 10. The pulse according to claim 9, further comprising time changing means for changing the driving speed at the time of starting or stopping the driving according to the driving speed and changing the time for changing the shape of the driving current waveform. Motor drive control device. 11. A pulse motor according to claim 9, further comprising a waveform changing means for changing a drive speed at the start or stop of the drive according to the drive phase position to change the shape of the drive current waveform. Drive control device. 12. A pulse motor, at least two PWM signal generating means capable of setting a duty ratio for generating a PWM signal, and driving means for driving the pulse motor substantially in a sine wave by an output signal from the PWM signal generating means. ,
A pulse motor comprising: a drive control means for controlling the drive means; and a waveform changing means for changing a shape of a drive current waveform by changing a duty ratio of PWM for a certain period of time when driving is started or stopped. Drive control device. 13. The apparatus according to claim 12, further comprising a waveform changing means for changing the shape of the drive current waveform by changing the PWM duty ratio and the drive speed when the drive is started or stopped according to the drive speed. The pulse motor drive control device according to the above. 14. A system according to claim 1, further comprising a period changing means for changing a period for changing the shape of the driving current waveform by changing a duty ratio of the PWM at the time of starting or stopping the driving according to the driving speed. 13. The pulse motor drive control device according to claim 12. 15. The apparatus according to claim 12, further comprising a waveform changing means for changing the shape of the drive current waveform by changing the duty ratio of the PWM at the start or stop of the drive according to the drive phase position. Pulse motor drive control device. 16. A pulse motor, driving means for driving the pulse motor substantially in a sine wave, drive control means for controlling the driving means, and when driving is started or stopped according to the driving speed or the driving start and stop phases. A pulse motor drive control device comprising: a waveform change unit that changes a shape of a drive current waveform by changing a drive period, a duty ratio of PWM, and a drive speed. 17. A storage medium for storing a program for controlling a pulse motor drive control device, the drive module having a drive step of driving a pulse motor with a substantially sine wave,
A drive control module of a drive control step for controlling the drive step, and a first method for changing the shape of the drive current waveform by changing the drive speed for a certain period when the drive is started or stopped.
A storage medium storing a program having a first waveform change module of the waveform change step. 18. The program according to claim 18, wherein the program has a time changing module of a time changing step of changing the driving speed at the time of starting or stopping the driving according to the driving speed and changing the time of changing the shape of the driving current waveform. Claim 17
The storage medium according to the above. 19. The program according to claim 19, wherein the program changes a drive waveform at a start or a stop of the drive according to a drive phase position to change a shape of the drive current waveform. 18. The storage medium according to claim 17, comprising: 20. A PWM signal generating module of at least two PWM signal generating steps capable of setting a duty ratio for generating a PWM (pulse width modulation) signal, and a pulse motor is driven by a substantially sinusoidal wave by an output signal from the PWM signal generating step. A drive module of a drive step to drive;
A drive control module for a drive control step for controlling the drive step;
A storage medium storing a program having a first waveform changing module in a first waveform changing step of changing a shape of a drive current waveform by changing a duty ratio of M. 21. The second program in a second waveform changing step of changing the shape of the drive current waveform by changing the PWM duty ratio and the drive speed at the start or stop of the drive according to the drive speed. The storage medium according to claim 20, further comprising a waveform changing module. 22. The program has a period changing module of a period changing step of changing a period for changing the shape of the drive current waveform by changing the duty ratio of the PWM at the time of starting or stopping the driving according to the driving speed. 21. The storage medium according to claim 20, wherein: 23. The third waveform changing step of the third waveform changing step of changing the shape of the driving current waveform by changing the PWM duty ratio at the time of starting or stopping the driving according to the driving phase position. 21. The storage medium according to claim 20, comprising a module. 24. A drive module of a drive step for driving a pulse motor substantially in a sine wave, a drive control module of a drive control step for controlling the drive step, and a drive start or a drive start or stop phase depending on a drive speed or a drive start and stop phase A storage medium storing a program having a waveform change module of a waveform change step of changing a shape of a drive current waveform by changing a drive period, a duty ratio of PWM, and a drive speed when stopped.