JP3427406B2 - Motor control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device, and more particularly to a motor control device which is used in an image reading device and which controls the motor by detecting the speed and movement amount of a slider by an encoder pulse.

[0002]

2. Description of the Related Art In a motor control device used in an image reading apparatus, a slider is driven by a DC motor. In such a device, an encoder pulse is transmitted from an encoder mounted on the motor shaft to the motor control CPU.
And the CPU controls the motor by an interrupt routine.

In such a control method, the interrupt time interval differs depending on the slider speed, and if the slider speed is too fast, the interrupt interval becomes shorter than the processing time of the CPU and correct control cannot be performed. In order to solve this, a method of dividing the pulse by the speed of the slider to lengthen the interrupt interval has been considered.

[0004]

The above-described method has been considered in the motor control device used in the conventional image reading apparatus. However, in the conventional method, the frequency division number is selected only by the speed of the slider, and the fluctuation of the processing time is not taken into consideration. Therefore, if the processing time is almost constant, there is no particular problem even if the control is performed by the conventional method. However, when the processing time of the CPU fluctuates greatly, the conventional method is suitable for the image reading apparatus. It is difficult to control.

The present invention has been made to solve the above problems, and it is an object of the present invention to enable accurate control even when the processing time for pulse processing varies in a motor control device.

[0006]

A motor control device according to the present invention comprises a driving means for driving a moving body in different driving modes , a means for outputting a pulse signal according to a moving amount of the moving body, and a pulse signal means for performing a predetermined pulse processing for each predetermined number of edges or falling or falling edge of <br/> di rising,
And means for controlling the driving means in response to the pulse processing, wherein the control means controls the moving speed of the moving body and the driving mode of the driving means.
Based on the between Pulse processing to be set to a different value according to de and means for identifying a number of predetermined edge. Preferred
Or, the means to identify the number of edges is
Based on the moving speed and the pulse processing time, the pulse signal is
Divides the pulse signal output by the output means into a predetermined number.
Including means. In another aspect of the present invention, a motor control device includes a driving unit that drives a driven body in different drive modes , an output unit that outputs a pulse signal according to a movement amount of the driven body, and a pulse signal as a trigger. and means for initiating a control process for controlling the drive means as, based on between time <br/> control processing is set to a different value depending on the driving mode of the mobile speed <br/> drive means of the driven body Te, and means for identifying a pulse signal as a trigger. Preferably, the pulse signal is specified
The means to do is the current moving speed of the driven body and the control processing time.
Based on the number of pulse signals output by the output means,
Including means to divide

[0007]

In the motor control device according to the present invention, not only the moving speed of the moving body but also the driving mode of the driving means is adjusted.
Flip even while Pulse processing which is set to a different value for determining the predetermined number of edges to perform in consideration pulsed. In another aspect of the present invention, the motor control device is a driven body.
To a different value depending on the moving speed of the
On the basis of the between-time control processing is set to identify the pulse signal to trigger.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a schematic configuration of an image reading device to which a motor control device according to the present invention is applied. Referring to FIG. 1, the image reading apparatus includes a glass table 2 on which an original 1 is placed.
And a slider 3 provided under the glass table 2 and a motor 9 for driving the slider 3. The slider 3 is composed of an illumination lamp 4, a mirror 5, etc., and the original 1 is illuminated by the illumination lamp 4 through the original placing glass 2 to obtain reflected light of the original 1. The reflected light is mirrors 5, 6a, 6b, lens 7
Is sent to the light receiving section 8 through the. The slider 3 is driven by a motor 9 and moves in the left-right direction as indicated by an arrow in the figure to read the entire original 1.

The light receiving portion 8 receives the reflected light of the document and converts it into an electric signal. The obtained electric signal is sent to an external device (not shown) such as a printer including an image processing unit (not shown).

An encoder 10 is provided on the rotating shaft of the motor 9, and outputs a pulse every minute rotation of the motor 9. The encoder 10 is connected to the controller 11, and the output pulse from the encoder 10 detects the speed and movement amount of the slider 3. Based on this, the control unit 11 controls the operation of the slider 3 by controlling the amount of electricity supplied to the motor 9, the direction of electricity supply, and the like.

FIG. 2 is a block diagram showing a main part of a control circuit of a motor control device to which the present invention is applied.

Referring to FIG. 2, the control unit 11 includes a microcomputer 4
1. The microcomputer 41 includes a CPU 42 and a ROM 4
3, RAM 44, input port 45, output port 46, P
WM (Pulse Width Modulatio)
n) Output port 47, register 48, timer unit 4
9. It includes an oscillator circuit 50 for generating an internal system clock fclk. In addition to the counter XF that counts the encoder pulse e as the position information of the slider 3 as it is, the timer unit 49 divides the input of the encoder pulse e during the return of the slider 3 to generate an interrupt, and generate an interrupt each time. A frequency divider circuit FDC for counting the count of the counter XF by a predetermined amount is included. The predetermined amount for counting the count XF is counted by the frequency division number set according to the current speed of the slider 3 and the program processing time required for the control flow 1 routine in the control flow described later.

Next, the control contents of the frequency dividing circuit FDC will be described with reference to FIG. In FIG. 3, (a) shows a pulse signal output from the encoder 10 (pulse signal input to the frequency dividing circuit FDC). In the frequency dividing circuit FDC, for example, the frequency division number 3 is set for the pulse signal input from the encoder 10. In the case of 2 and 1, signals as shown in (b), (c) and (d) in the figure are output respectively, and these signals are output to the CPU 4
Entered in 2. Thus, in the frequency dividing circuit FDC, for example, when the frequency dividing number is 3, the pulse signal is output to the CPU 42 only when the pulse signal is detected for the third time. On the other hand, the frequency dividing circuit FDC divides the pulse from the encoder 10 according to the frequency dividing number set by the CPU 42.

Returning to FIG. 2, the input port 45 has a photographing magnification signal MAG and a scanning start request signal S from the master.
A signal HOME indicating whether the CAN and the slider 3 are in the home position is given. The signal MAG indicates the copy magnification selected in the image reading device, and the microcomputer 41
Then, the scanning speed is set accordingly.

The signal SCAN is normally "low" and is made "high" when a running start request is made. The signal HOME is "high" only when the slider 3 is at the home position.
And otherwise "low".

A forward / reverse rotation signal f of the motor 30 is output from the output port 46, and this is input to the input terminal 35a of the drive circuit 51 of FIG. The PWM output is acceleration scan control from the start of scanning to constant speed scanning (indicated by the acceleration mode in the following flowchart), constant speed scanning control (constant speed mode in the following flowchart), or return after constant speed control. The pulse duty is set to 100% for deceleration control until the start. From the PWM output port 47, a P such as a pulse whose off time is controlled by interrupt control (S18 to S39 in the flowchart described later) performed at the on edge of the pulse signal frequency-divided by the frequency dividing circuit FDC.
The WM motor energization pulse d is output, and this is the drive circuit 5
1 is input to the input terminal 35b. The motor 9 is controlled by these inputs.

Next, referring to FIG. 4, the movement mode of the slider 3 in each mode will be described. FIG. 4 is a diagram showing each operation mode of the slider 3 and the moving speed of the slider 3 at that time, and is a schematic diagram showing the movement of the slider when the time is taken on the x-axis and the moving speed of the slider is taken on the y-axis. is there.
In the figure, a, b ... Show each mode, y1 shows the target speed of the slider 3 at the time of scanning, and y2 shows the target speed of the slider at the time of return.

First, the acceleration mode a will be described. This mode corresponds to scanning. When the scan start signal is input to the microcomputer 41, the control flow of the slider drive motor 9 described later is started, the motor 9 is rotated in the normal direction, and the slider 3 is started to move from the home position in the scan direction. Then, while the current moving speed of the slider 3 is from zero to the target speed y1, the duty of the energizing pulse of the motor 9 is set to 100%, the energization of the motor 9 is turned on, and the slider 3 is accelerated in the scanning direction.

Symbol b represents a constant speed mode during scanning. When the current moving speed of the slider 3 reaches the target speed y1,
As in the acceleration mode, the duty of the energizing pulse of the motor 9 is set to 100%. In order to suppress the speed fluctuation of the slider 3 from the target speed y1, when the current moving speed of the slider 3 <target speed y1, the motor 9 is turned on (duty 100%).

Current slider moving speed> target speed y1
At this time, the motor 9 is turned off (duty 0%), and the slider 3 is controlled so as to stably maintain the target speed.

Reference numeral c is a deceleration mode during scanning, and when the amount of movement of the slider 3 from the scan start position to the current position reaches the target movement amount in the constant speed mode, control of the deceleration mode is executed. In this control, since the slider 3 is decelerated from the target speed to zero and stopped, the energizing pulse duty of the motor 9 is set to 100% and the rotation direction of the motor is switched from normal rotation to reverse rotation to apply a braking force to the slider, as described above. The motor 9 is driven to give it.

Next, the moving speed of the slider 3 becomes zero d
The neighborhood will be described. Slider 3 in deceleration mode
When the moving speed of 3 reaches the stop detection speed, it is considered that the slider 3 has stopped. The rotation direction of the motor 9 is kept forward,
The energizing pulse duty of the motor 9 is set to 100%, and the return of the slider 3 is started.

E is an acceleration mode at the time of return. The rotation direction of the motor 9 is reverse and the movement direction of the slider 3 is the return direction. The subsequent control is the same as the control in the acceleration mode (a) during scanning.

Reference numeral f is a constant speed mode at the time of return. This is also a constant speed mode during scanning (b) except for the motor rotation direction
It is similar to the control of.

G is a deceleration mode at the time of return. This is also the deceleration mode during scanning (c) except for the motor rotation direction.
It is similar to the control of.

Next, the moving speed of the slider 3 becomes zero h
Control will be described in the vicinity. When the moving speed of the slider 3 decelerates to the stop detection speed y4 in the return deceleration mode, it is considered that the slider 3 has stopped, the motor is turned off, and the slider 3 is stopped at the home position.

Thereafter, the slider 3 is stopped at the home position until the next scan start signal is input, and the above control is executed only when the scan start signal is input again.

Next, the specific control contents of the slider 3 will be described with reference to the flow charts of FIGS. 5 and 6. The control content is divided into an acceleration control mode before the slider 3 reaches the target speed (mode a above) and a constant speed control mode after the target speed reaches mode b).
It is assumed that the processing time in the flow differs greatly depending on the difference between the two modes, and the processing time in the entire flow also greatly differs depending on the mode.

The following control is executed only when a scan start signal is input to the microcomputer 41. First slider 3
The scanning direction is set as the moving direction of the (step S11, the following steps are omitted). Next, after the scan start signal is input, in order to move the slider 3 from the home position in the scan direction, the energization direction (+ or −) of the motor 9 is set so that the rotation direction of the motor 9 is forward (S12). .

In S13, the movement amount of the slider 3 is reset to zero. This step is executed only when the slider 3 is at the scan start position (home position) or at the return start position. Next, the flag indicating the acceleration mode is set as the flag indicating the control mode, and the acceleration mode processing time required for the program processing in the acceleration mode is set as the program processing time (S14, S1).
5). Here, the processing time represents the time required for the flowchart 1 loop in the current control mode, and the acceleration mode processing time represents the time required for the flowchart 1 loop in the acceleration mode.

In S16, since the acceleration is not yet started at this time, the frequency division number of the frequency dividing circuit FDC is reset to 1 and the duty PWM of the energizing pulse of the motor is set to 100% (S1).
7).

Next, the pulse signal output from the encoder 10 and the frequency dividing circuit FDC will be described with reference to FIG. 7 for easy understanding of the following steps. 7A shows the pulse signal output from the encoder 10, that is, the pulse signal before frequency division, and FIG. 7B shows the pulse signal output from the frequency dividing circuit FDC, that is, the pulse signal after frequency division. In (a), the pulse signal has a rising edge e. When the frequency division number in the frequency divider circuit pulse signal is 1, the interrupt control start position i1 corresponds to the rising edge e.
Becomes Consider a state in which the motor 9 is rotated at a high speed, and the frequency division number in the frequency dividing circuit FDC is changed from 3 to 4 while the pulse frequency from the encoder 10 is increased as shown in the right side of the figure. At this time, d1 indicates the signal width of the pre-dividing pulse in the previous interrupt control, i2 indicates the previous interrupt control start position, and i3 indicates the current interrupt control start position. Further, d2 represents the pulse width from the pulse signal input after the previous frequency division to the pulse signal input this time after the frequency division.

Referring to FIG. 2, CPU 42 receives only a pulse signal (a signal shown in FIG. 7B) divided by frequency dividing circuit FDC. Referring to FIGS. 5 and 7, C
When a pulse signal after frequency division is input to the PU 42 (S18
Only when YES), the interrupt control of S19 to S38 is executed.

In S19, the number of pulse signal outputs from the pulse encoder (the number of pulse signal outputs before frequency division), which is the amount of movement of the slider 3 from the scan start position to the current position, is calculated. Specifically, the current slider movement amount is calculated by adding the division number, which is the slider movement amount from the previous pulse signal input after frequency division to the pulse signal input after frequency division this time, to the movement amount during the previous interrupt control. And

Next, in S20, the pulse width of the pre-dividing pulse signal in the previous interrupt control is calculated. The pulse width is the time from the rising edge of the pulse signal to the rising edge of the next pulse signal or the count value of the counter. Here, the pre-division pulse width is the time from the rise of the post-division pulse signal in the previous interrupt control to the rise of the post-division pulse signal in the current interrupt control.
It is obtained by dividing the pulse width after frequency division by the frequency division number N set in S20 in the interrupt control performed two times before. By this calculation, the pre-dividing pulse signal and the pulse width at the time of the previous interrupt control can be obtained. In S20, the pre-division pulse width was calculated using the frequency division number N set in S22 in the pre-preceding interrupt control. However, when the frequency division number N is set in S20, the value is stored in the RAM. It is assumed that the data is recalled in the form stored in the FIFO memory in the next and subsequent control.

Next, in S21, the slider speed at the time of the previous interrupt control is calculated. Specifically, it is calculated by dividing the amount of movement of the slider that moves by one encoder pulse by the pulse width before frequency division obtained in S20. Here, the slider speed represents the current slider speed.

In S22, the frequency division number of the frequency dividing circuit FDC after the current interrupt control is set. In the present invention, the frequency division number of the frequency dividing circuit FDC is set according to the current slider movement speed and the processing time required for the interrupt control processing. Specifically, in S22, the frequency division number N = (processing time required for interrupt control / pulse width before frequency division (obtained in S20)) + 1 is set.

At least processing time ≦ pulse width before frequency division × N
Otherwise, there will be no room in processing time. This state is shown in Figure 8.
Will be described with reference to. In FIG. 8, (a) represents a pulse before frequency division, and (b) represents a pulse after frequency division. W1 in the figure
Represents the pulse width before frequency division, and e represents the rising edge. i1 represents the last interrupt control position, i2 represents the current interrupt control position, i3 represents the next interrupt control position, and i4 represents the next interrupt control position.

Referring to FIG. 8, when the interrupt control is started from the pulse signal rising edge i3 after frequency division, the interrupt control may not be completed by the next pulse signal edge i4 after frequency division. Therefore, in S22, the frequency division number is set by the above-described formula. By this calculation, as described above, the interrupt control can be surely completed before the pulse signal rises after the next frequency division, and the minimum frequency division number can be set. Therefore, the interrupt control can be performed at the minimum interval. .

It is assumed that the frequency division number set in the current interrupt control is divided by the pre-frequency division pulse signal (after c in FIG. 8) after the next interrupt control. .

Next, the motor energization control in each mode after S23 will be described with reference to FIG. First, in S23, the control mode is determined, and the control mode is divided into an acceleration mode, a constant speed mode, and a deceleration mode. First, in the acceleration mode, until the slider moving speed reaches the target speed (S2
4 is NO), the energization pulse duty of the motor 9 is 100
%, And the motor energization ON state continues (S17). When the slider speed reaches the target speed (YES in S24), the mode is set to the constant speed mode and the processing time is set to the processing time of the constant speed mode (S25, S26).

When it is determined in S23 that the mode is the constant speed mode, the duty of the energizing pulse of the motor for moving at the target speed with respect to the slider 3 moving at the speed obtained in S21 is calculated (S27). . Next, a process for preventing the duty calculated in S27 from exceeding 100% or 0% is performed (S28-S31).
As a result, measures against overflow in the case of performing incorrect calculation processing in S20, 21 and 27 are performed.

When the slider movement amount reaches the target movement amount in S32, in other words, when the slider 3 reaches the predetermined position (YES in S32), the mode is set to the deceleration mode (S3).
3), the processing time is the deceleration mode processing time (S3)
4).

Next, the processing when it is determined in S23 that the control mode is the deceleration mode will be described. When the slider 3 is scanning (YES in S35), the rotation direction of the motor 9 is changed from normal rotation to reverse rotation (S36), and a load in the return direction is applied to the slider 3 which is moving in the scanning direction to cause the slider 3 to move. Is decelerated (S38). When the slider 3 is returning (NO in S35), the rotation direction of the motor 9 is changed from reverse to forward to apply a load in the scan direction to the slider 3 moving in the return direction to decelerate the slider (S40). .

Next, when the slider speed ≦ the stop detection speed (YES in S39), it is considered that the slider 3 has stopped, and the duty of the motor energizing pulse is set to 0% (S4).
0). If the slider movement direction is the scan direction (S
(YES in 41), the movement direction of the slider 3 is set to the return direction, and the rotation direction of the motor 9 is set to the reverse direction (S42, S).
43), return is started, and the above-mentioned acceleration, constant speed, and deceleration control is executed again.

On the other hand, when the moving direction of the slider 3 is the return direction (NO in S41), the control is ended.

Finally, the specific effect of the present invention will be described with reference to FIG. 9A is a diagram showing a conventional case (A) and a case (B) to which the invention of the present application is applied in a portion where the acceleration control (a) and the constant speed control (b) shown in FIG. 4 are switched. is there. In the figure, (i) is an output pulse of the pulse generator, (ii) is an input pulse to the microcomputer 41, and (iii) is a processing time in the microcomputer 41. As described above, it is assumed that the control unit performs different processing during acceleration control and constant speed control, and the processing time during acceleration control is about half the time required during constant speed control. The target speed needs to be divided by a frequency division number of 2 or more in order to perform normal processing during constant speed control, but the speed need not be divided during acceleration control with a short processing time.

In the prior art of (A), since the frequency division number is determined regardless of the processing time of the control section, the pulse is divided into two and sent to the control section during acceleration control as in constant speed control. , Unnecessary frequency division. On the other hand, (B)
In this case, the frequency is not divided during acceleration control, so that the number of times of processing during acceleration can be increased and fine acceleration control can be performed. Especially in the case of acceleration control, fine control is effective in reducing overshoot.

Although the duty of the motor energizing pulse is calculated only in the constant speed mode in the above embodiment, the duty may be calculated also in the acceleration and deceleration modes. However, at this time, the processing time also becomes longer in the acceleration mode and deceleration mode, but if these processing times are shorter than the processing time in the constant speed mode, the overshoot is reduced and Stabilization of movement can be achieved.

In the above embodiment, the speed of the slider 3 is controlled so as to be the same as the target speed during scanning in the constant speed mode during returning. However, the target speed during returning is set higher than during scanning. Good. Further, at the time of return, the control in the constant speed mode may not be performed, and only the control in the acceleration mode and the deceleration mode may be performed. As described above, the present invention in which the frequency division number is set according to the slider speed and the processing time can be applied to all motor control devices that continuously control each mode with a different processing time during the speed control of the slider. .

Further, in the above embodiment, the target speed during scanning is set to a constant value, but the target speed during scanning in the digital PPC may be appropriately changed according to the scaling factor. The present invention is also applicable to an analog PPC system device.

[0052]

As described above, according to the present invention, not only the moving speed of the moving body but also the driving mode of the driving means is determined.
Determining a predetermined number of edges in consideration of between Pulse processing to be set to different values perform pulse processing. In another aspect of the present invention, the moving speed and the driving speed of the driven body are
Depending on the driving mode of the motion means on the basis of the between-time control <br/> processing to be set to different values, to identify the pulse signal to trigger. As a result, it is possible to provide the motor control device can be controlled with accuracy even if the processing time varies.

When the present invention is used in a motor control device for driving a slider of an image reading device, the acceleration mode is set to a constant value as compared with the conventional case where the frequency division number is set according to the speed of the slider. Since the interrupt control is performed at finer intervals during the transition to the high speed mode, it is possible to detect that the slider speed has reached the target speed faster and switch from the acceleration mode to the constant speed mode. The amount of overshoot can be reduced. Furthermore, the slider speed can be stabilized at the target speed faster.

Further, since the minimum frequency division number can be set according to the size of the processing time and the speed of the slider, the motor energizing pulse duty can be set at the minimum interrupt interval even at the constant speed. The speed fluctuation in the constant speed mode can be reduced.

Further, even in the deceleration mode, the interrupt control can be performed at a fine interval. Therefore, when the braking force is applied to the slider 3, the slider moving speed becomes equal to or lower than the stop detection speed as shown in the above-mentioned flowchart. It is possible to detect the fun early. As a result, there is no inconvenience that the motor cannot be stopped at the predetermined position by detecting this after the detection has been delayed and the slider has already reversed the traveling direction. It can be stopped at a predetermined position (home position).

In this embodiment, the rising signal is used for the interrupt control, but the falling signal may be used.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an image reading apparatus to which the present invention is applied.

FIG. 2 is a block diagram showing a main part of a control unit of an image reading apparatus to which the present invention is applied.

FIG. 3 is a diagram showing a signal output from a frequency dividing circuit.

FIG. 4 is a diagram showing a movement mode of a slider.

FIG. 5 is a flowchart showing the operation of the motor control device according to the present invention.

FIG. 6 is a flowchart showing the operation of the motor control device according to the present invention.

FIG. 7 is a diagram showing pulse signals before and after frequency division.

FIG. 8 is a diagram showing pulse signals before and after frequency division.

FIG. 9 is a diagram showing a specific effect of the present invention.

[Explanation of symbols]

41 Microcomputer 42 CPU 45 input ports 46 output ports 47 PWM output port 48 registers 49 timer unit 50 oscillation circuit

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H02P 5/00-5/26 H02P ^7/ 00-7/34 H04N 1/04 105

Claims (4)

(57) [Claims] 1. A driving means for driving a moving body in different driving modes , a means for outputting a pulse signal according to a moving amount of the moving body, and a rising edge or a falling edge of the pulse signal.
A means for performing a predetermined pulse processing for each predetermined number of, and a means for controlling the driving means in response to the pulse processing, wherein the control means has a moving speed of the moving body and the driving means.
Based on the inter-pulse time processing <br/> to be set to a different value according to the drive mode and means for identifying the number of said predetermined edge, the motor control device. 2. The means for specifying the number of edges is the
Based on the current moving speed of the moving body and the pulse processing time.
The pulse output by the means for outputting the pulse signal
The method of claim 1, including means for dividing the signal into a predetermined number.
Motor control device. 3. Driving means for driving a driven body in different driving modes , output means for outputting a pulse signal according to a movement amount of the driven body, and controlling the driving means by using the pulse signal as a trigger. Means for starting a control process, a moving speed of the driven body and a driving mode of the driving means.
In response based on the between-time control processing to be set to different values,
A motor control device comprising: a means for specifying a pulse signal to be a trigger. 4. The means for identifying the pulse signal is the
Based on the current moving speed of the driven body and the control processing time
The pulse signal output by the output means to a predetermined number.
4. The motor control device according to claim 3, further comprising means for rotating.