JP2002232651A - Motor drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the capacitance and processing load of a frequency table in controlling the rotating speed of a motor by the frequency data of a drive pulse of the motor. SOLUTION: A basic frequency table corresponding to the basic rotating speed of the motor is stored in the built-in RAM 23a of a motor control ASIC 23, a CPU 24 sets thinning data corresponding to the rotating speed of the motor to be controlled in the ASIC 23, and the ASIC 23 thins the frequency data of the basic frequency table in accordance with the thinning data instructed by the CPU 24 and reads the thinned frequency data as the frequency data of the drive pulse of the motor 21. The CPU 24 also sets clock frequency data corresponding to the rotating speed of the motor to be controlled in the ASIC 23, and the ASIC 23 reads the frequency data of the basic frequency table with a clock frequency corresponding to the clock frequency data instructed by the CPU 24 and drives the motor 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving device for controlling the speed of a moving body such as a scanner by controlling the number of rotations of a motor such as a stepping motor.

[0002]

2. Description of the Related Art Generally, in driving control such as driving a moving body such as a reading head of a scanner, various motors are used to accurately control the driving position of the moving body. Since control can be performed, it is frequently used in recent years. The rotation speed of the stepping motor changes in accordance with the frequency (period) of the pulse given as the driving pulse, and accordingly, the moving speed of the reading head, which is a moving body, changes.

When the copy magnification is changed, or when the color and black / white writing speeds are different, the moving speed of the read head also needs to be changed in accordance with the copying magnification and the writing speed. Therefore, in order to change the moving speed of the read head, data of the pulse frequency according to the set acceleration is required as a table from the stop of the read head to the set moving speed.

For example, as shown in FIG. 9, in a motor drive device in which a drive circuit 12 for a motor 11 is directly controlled by a CPU 13, frequency data required for acceleration is stored in a RAM 14 and sequentially stored in accordance with the acceleration of the motor 11. , RAM1
The CPU 14 reads the data of No. 4 and sets the data in the drive circuit 12, whereby the acceleration profile of the motor 11 is set. In such a configuration, it is not possible to store the frequency data corresponding to the set speeds at all the magnifications in the RAM 14 due to the limitation of the storage capacity of the RAM 14, so that the magnification is changed in order to reduce the storage capacity of the RAM 14. Each time, the frequency data is recalculated by the CPU 13 and transferred to the RAM 14, which is read out and set in the drive circuit 12.

Conventional methods for accelerating a stepping motor include a method for obtaining an optimum acceleration profile and a method for driving the motor using the acceleration profile, which requires a storage capacity for frequency data indicating the acceleration profile. Methods have been proposed to reduce this. For example, in the invention described in Japanese Patent Application Laid-Open No. 7-163195, a method has been proposed in which pulses of frequency data are calculated by a recurrence formula to reduce the RAM capacity as a storage area.

In the invention described in Japanese Patent Application Laid-Open No. H10-257244, reference table data indicating a target pulse period when accelerating to a set speed is stored in a RAM, and an arbitrary target speed is set based on the reference table data. A method has been proposed in which a target pulse cycle for each pulse until acceleration is calculated by a CPU to generate arbitrary table data.

Further, in the invention described in Japanese Patent Application Laid-Open No. 8-168297, a method is proposed in which the load on software is reduced by hardware for dividing a pulse, and recalculation of an acceleration profile is not required.

[0008]

By the way, with respect to an analog copying machine, in a recent digitized copying machine, a scanner mechanism is designed separately from a printer mechanism, and an option that can be retrofitted is provided. It is generally supplied as a part. An optional ASIC (IC for specific application) for controlling the motor as shown in Fig. 1 in order to reduce the cost, simplify the control software, and reduce the load on the main control CPU. 23 in many cases.

When such a control ASIC 23 is used, a frequency table for obtaining an acceleration curve is expressed by ASI
C23 is stored in a built-in RAM 23a, and the built-in RAM 23a is also kept to a minimum capacity for cost reduction. Therefore, the frequency table corresponding to the optimal acceleration curve when the set speed is changed is
Since all of them cannot be stored in the RAM 23a in the ASIC 23, when changing the acceleration curve, the CPU 2
After performing the calculation processing on the 4 side, it is necessary to perform the re-transfer processing to the ASIC 23. Therefore, such recalculation and retransfer processing undesirably increases the number of programs and the processing time for the CPU 23.

Further, in recent color copiers, due to the difference in print processing time between color and black and white, there are many methods of increasing the reading speed in black and white and increasing the throughput. For example, as shown in FIG.
When the set speed at the time of the color equal magnification is 125 [mm / sec] and the set speed at the time of the black and white equal magnification is 185 [mm / sec], the zoom range is set to 5
To perform the reading at 0 to 200%, the reading speed is 62.5 [mm
/ sec] to 370 [mm / sec].
For all of these set speeds, the acceleration area needs to be within the approach distance range 31 from the start of acceleration to the reading speed 32. As the set speed increases, the time required for acceleration increases. It becomes longer and the margin until the reading is actually performed after the reading speed 32 is reached is reduced.

Further, as shown in FIG. 11, the vibration 43 generated by the acceleration needs to be settled by the end of the approach distance 41 and the start of reading (shown in FIG. 42). The time until it stops (damping characteristic) does not change much even if the set speed changes, or the time until it stops becomes longer as the final speed increases. In such a case, in order to lengthen the time until the vibration stops, in the case of a high set speed, the acceleration is increased to shorten the acceleration distance 31, and the vibration is accommodated at the remaining approach distance, or the acceleration is gradually reduced. In general, a method is set in which an acceleration curve is set so as to suppress occurrence of vibration.

However, the incorporation of the processing functions as described above into the dedicated ASIC 23 for controlling the motor 21 increases the number of gates of the ASIC 23, which results in a cost reduction. If the ASIC 23 does not incorporate the processing functions as described above, calculation processing and frequency table transfer processing by the CPU 24 are required before the scanner starts to be driven. Will be invited.

Further, in controlling the motor drive by the dedicated ASIC 23, the processing circuit prepared in the ASIC 23 needs to be a simple one that can be incorporated.
In controlling the ASIC 23 itself, the main CPU
The processing load and the processing time from 24 need to be as simple and short as possible. However, Japanese Patent Application Laid-Open Nos. 6-98599 and 8-16
In Japanese Patent No. 8297, the generation of the drive pulse itself only needs to specify the data table to be set in the counter. However, when the drive conditions such as the magnification and the acceleration change, the data table to be set is processed from the beginning. Therefore, there is a problem that the processing load and the transfer processing time on the main CPU side increase.

Further, in these conventional methods, since only the method of dividing the data to be set is used, when the acceleration pattern is changed to suppress vibration,
The main data of the table to be set is
Since it is necessary to calculate in U, the problem of an increase in processing load remains. Furthermore, in the case of Japanese Patent Application Laid-Open No. Hei 10-257244, a problem of an increase in processing load, such as a complicated calculation on the main CPU side and a transfer process of the calculated result, similarly occurs.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a motor driving device capable of reducing the capacity of a frequency table and the processing load when controlling the number of rotations of the motor based on the frequency data of the driving pulse of the motor. The purpose is to provide.

[0016]

According to a first aspect of the present invention, there is provided a motor driving apparatus for controlling the number of rotations of a motor based on frequency data of a driving pulse of the motor. Storage means for storing a basic frequency table in which the basic frequency data corresponds to each address, and means for thinning out frequency data of the basic frequency table according to the number of rotations of the motor to be controlled and reading out the data as drive pulse frequency data of the motor And characterized in that:

The second means is the motor driving device of the first means, and further comprises a CPU and a motor drive IC having a built-in storage means. Transfer and store a basic frequency table, set thinning data according to the number of rotations of the motor to be controlled from the CPU to the motor drive IC,
The motor driving IC thins out the frequency data of the basic frequency table in accordance with the thinning data instructed by the CPU, and reads out the frequency data of the driving pulse of the motor.

The third means is characterized in that, in the first and second means, the number of rotations of the motor is changed by changing a thinning number of the frequency data.

The fourth means has a second storage means for storing a control table corresponding to the number of rotations of the motor controlled by the second or third means, the frequency data decimation number and the decimation end address. The CPU transfers a plurality of control data of a control table of a second storage means to the motor drive IC, and the motor drive IC thins out frequency data of the basic frequency table based on the plurality of control data and reads out the data. Thereby, the rotation speed of the motor is controlled by the acceleration profile approximated by a straight line.

The fifth means is a motor driving apparatus in which the motor drives the scanner in the fourth means, wherein the scanner reads an original at different magnifications in accordance with the number of rotations of the scanner. The control table stored in the second storage means is constituted by using the scaling factor corresponding to the rotation speed of the motor to be controlled as an index, and the CPU sets the thinning number and the thinning end address of the frequency data according to the designated scaling factor. It is characterized by reading out from the second storage means and instructing the motor drive IC.

The sixth means is a motor driving device for controlling the number of rotations of the motor based on the frequency data of the driving pulse of the motor, wherein the basic frequency data corresponding to the basic number of rotations of the motor corresponds to each address. And a means for driving the motor by reading out frequency data of the basic frequency table as frequency data of drive pulses of the motor at different clock frequencies according to the number of rotations of the motor to be controlled. It is characterized by.

A seventh means is the motor driving device according to the sixth means, further comprising a CPU and a motor drive IC having a built-in storage means, wherein the CPU transmits the data to the storage means in the motor drive IC. A basic frequency table is transferred and stored, and the CPU sets clock frequency data corresponding to the number of rotations of the motor to be controlled from the CPU to the motor drive IC, and the motor drive IC sets the clock frequency specified by the CPU. The motor is driven by reading frequency data of the basic frequency table at a clock frequency corresponding to the data.

The eighth means is characterized in that the rotation speed of the motor is changed by changing the clock frequency in the sixth and seventh means.

The ninth means is the control means according to the seventh or eighth means, wherein a control table corresponding to the number of rotations of the motor to be controlled, the read start address of the basic frequency table, the number of reads and the clock frequency is stored. Wherein the CPU transfers a plurality of control data of the control table of the second storage means to the motor drive IC,
The motor drive IC reads frequency data of the basic frequency table based on the plurality of control data, thereby controlling the number of revolutions of the motor with an acceleration profile approximated by a straight line.

A tenth means is the motor driving apparatus according to the ninth means, wherein the motor drives a scanner, and the scanner reads an original at a different magnification according to the number of rotations. The control table stored in the storage means of No. 2 is constituted by using an index corresponding to the scaling factor corresponding to the number of rotations of the motor to be controlled, and the CPU stores the read start address corresponding to the designated scaling factor, the number of readings, and the clock frequency. It is characterized by reading out from the second storage means and instructing the motor drive IC.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a motor driving device according to the present invention, FIG. 2 is an explanatory diagram showing a basic frequency table and another frequency table, and FIG. 3 is a control table of a RAM on the CPU side in FIG. FIG. 4 is an explanatory diagram showing a driving example of the motor driving device of FIG. 1, and FIG. 5 is an explanatory diagram showing an acceleration profile of the motor driving device of FIG.

In FIG. 1, a motor 11 drives a moving body, and a motor drive circuit 22 drives the motor 11 based on a motor control signal from an ASIC 23. ASIC23
Has a built-in RAM 23a for storing only a basic frequency table 61 corresponding to a basic acceleration curve as shown in FIG. 2, for example.

In the first embodiment, when the scanner motor control is performed by the dedicated control ASIC 23, the built-in RAM is used to solve the problem as in the conventional method.
The frequency data of the basic frequency table 61 in 23a is C
By providing the control ASIC 23 with a function of thinning out and reading in accordance with an instruction from the PU 24, calculation processing and table transfer processing by the CPU 24 before scanner driving is started is reduced.

Further, in order to realize an acceleration curve other than the acceleration curve of the basic frequency table 61, the RAM 25 of the CPU 24 stores a magnification 71 as an index corresponding to each acceleration curve as shown in FIG. A control table including a thinning value 72 of the basic frequency table corresponding to the acceleration curve and a final address 73 of the basic frequency table corresponding to each acceleration curve is stored. And CPU
24 reads out the decimation value 72 and the final address 73 of the basic frequency table 61 according to the designated scaling factor from the RAM 25 and sends them to the ASIC 23. The ASIC 23 thins out and reads out the frequency data of the basic frequency table 61 thereby,
This is applied to the motor drive circuit 22 as a motor control signal corresponding to the acceleration curve.

For example, a fundamental frequency table 61 shown in FIG.
In the case of a scanner motor mechanism configured to travel a distance of 1 [mm] by one pulse as shown in FIG.
At 0 [mm / sec ² ], the moving distance is 20 [mm] in the state of the 20th pulse, and the arrival speed is 447.2 [mm / s].
ec]. On the other hand, acceleration =
In the case of driving at 10,000 [mm / sec ² ], the moving distance is 10 [mm] in the state of the tenth pulse, and the arrival speed is also 447.2 [mm / sec].

Now, in the RAM 23a of the control ASIC 23,
Acceleration = 5000 [mm / sec] as indicated by a curve 61 shown in FIG.
² ] is stored as the basic frequency table, and the CPU ^{2 is used} to realize acceleration = 10000 [mm / sec ² ] as shown by a curve 62 shown in FIG.
4 to the control ASIC 23, the value (1 in this example) for thinning out the basic frequency table 61 and the target speed (447 in this example) or the end data address (20 in this example) are transferred to the control ASIC 23. When the signal is transmitted, the control ASIC 23 skips the frequency table of acceleration = 5000 [mm / sec ² ] one by one and reads it out as shown by a curve 63 in FIG.
By accelerating 1, the motor 21 can be controlled by the same acceleration profile 63 as in the case of acceleration = 10000 [mm / sec ² ] as shown by a curve 62 in FIG. The control ASIC 23 also executes the next control table when the transferred target speed has been reached, and when there are no more control tables to be processed, it indicates that motor control has been completed.
It is sent to PU 24 as a motor end signal.

If the control ASIC 23 and the control method as described above are performed, the processing of the CPU 24 executed before the start of the motor driving is performed by combining the thinning value 72 of the control table of the RAM 25 with the target speed (or the final address 73 of the frequency table). And only the motor start signal is transmitted. Completion of the motor drive control means that the control AS
By processing the motor end signal from the IC 23 as an interrupt to the CPU 24, the processing of the CPU 24 during the motor drive control becomes unnecessary.

Further, on the CPU 24 side, the data of the frequency table for the target speed due to the change in the magnification range can be stored in a combination of the control table of “thinning value” and “target speed”. Since the combination of the control tables in the RAM 25 is very small as compared with the data of the frequency table, it is possible for the CPU 24 to store the combinations of the control tables at all the magnifications. In this case, it is possible to flexibly cope with a wide range of speed change only by a program process of transferring the control table data indexed by the scaling ratio 71 to the control ASIC 23 without executing a complicated program or calculation process. Become.

{Operation Example} One acceleration profile having a plurality of different accelerations can be realized from the basic frequency table 61 by transferring a control table corresponding to the number of accelerations. The above scanner motor mechanism and 5
When the basic frequency table 61 of 000 [mm / sec ² ] is used, for example, a control table: “decimated value = 1”, “final frequency table address = 9” control table: “decimated value = 0”, “final frequency table address” = 20 ”to the ASIC 23 and sends out a motor start signal.

The control ASIC 23 is a first control table.
Of the frequency table address
Read frequency data of dress = 1, 3, 5, 7, 9
The motor 21 is driven in accordance with the
The process moves to the control table. Second control table
Since there is no thinning value,
The motor uses all the data in the basic frequency table 61
21 is controlled. Processing of the second control table is completed
Upon completion, the control ASIC 23 outputs the motor end signal to the CP.
The data is sent to U24, and all the processes are completed. This time drive
The movement of the driven motor 21 is based on the first control table.
During processing = 10000 [mm / sec] ²],
During processing of the second control table, acceleration = 5000
[Mm / sec²One acceleration profile corresponding to
You.

Further, by increasing the number of control tables for one acceleration file, the acceleration curve 83 set by the curve as shown in FIG. 5A is smoothed as shown in FIG. Acceleration profile 84 approximated by a simple straight line
Can be set, and also in this case, the CP
The number of data to be sent from U24 will be the number of control tables. In the present embodiment, the acceleration profile 84 approximated to a straight line is set in such a manner that the thinning value of data is sequentially reduced. However, the setting for increasing or decreasing the thinning value is arbitrary within the driving limit range of the motor 21. Needless to say, it can be increased or decreased.

Further, since it is impossible to store the acceleration curve in the control ASIC 23 or the CPU 24 for the entire zoom range, in the conventional method, every time the zoom ratio changes and the set speed changes, the frequency data is regenerated. Although calculation and data transfer are required, in the present invention, as shown in FIG. 3, control table data composed of a thinning value 72 with a scaling factor as an index 71 and a final table address 73 are stored in the RAM 25 on the CPU 24 side. R is enough
The amount of data stored in the AM 25 is very small, and the control table data at all magnifications is stored in the CP.
It can be stored in the RAM 25 on the U24 side. Therefore, even if the set speed varies depending on the designated magnification, complicated program processing for recalculating the acceleration profile is not required, and the amount of data transferred to the control ASIC 23 can be reduced, so that the processing time can be reduced. Can be.

<Second Embodiment> Next, a second embodiment will be described with reference to FIGS. In the second embodiment, as shown in FIG. 1, in a configuration in which the scanner motor control is performed by the dedicated control ASIC 23, in order to solve the problem as in the conventional method, the control ASIC 23 has the same configuration as the first embodiment. By storing only a basic frequency table corresponding to a basic acceleration curve in the RAM 23a, calculation processing and table transfer processing by the CPU 24 before scanner driving is started is reduced. And
In the second embodiment, in order to realize an acceleration curve other than the basic frequency table, frequency data of the basic frequency is read out at different clock frequencies according to the acceleration curve, and the motor 21 is driven using this clock as a reference clock. .

For example, as shown in FIG. 6, it is assumed that a fundamental frequency table 51 configured to advance a distance of 0.5 [mm] by one pulse is given to the built-in RAM 23a. When the ASIC 24 processes the data in the frequency table 51 at the reference clock = 1 μsec (52), the first data is 0.020 as shown in the table 52.
It represents a cycle of seconds, and reference clock = 0.
If the time is 7 μs, the first
The second data will represent a period of 0.014 seconds.
That is, to move a distance of 0.5 mm, 0.020 seconds are required for the reference clock = 1 μsec, and 0.014 seconds are required for the reference clock = 0.7 μsec.

Similarly, given basic frequency table 5
The accumulated time for each movement distance when the reference clock is 1 μs and 0.7 μs for 1 data is the reference clock = 1.
In the case of μ seconds, 0.020 seconds as shown in Table 52,
0.028 seconds, 0.035 seconds ... Reference clock =
In the case of 0.7 μsec, 0.01 as shown in Table 53
4 seconds, 0.020 seconds, 0.024 seconds... Therefore, under the above conditions, the acceleration becomes 2500 [mm / sec ² ] when the reference clock is 1 μsec, and the acceleration is about 5100 [mm / s] when the reference clock is 0.7 μsec.
ec ² ].

Here, the value that can be selected as the reference clock is determined by a counter set in the ASIC 23 as 1,
Needless to say, it can be set arbitrarily by increasing to 2, 3,.... For example, when the reference clock is set to 1 μsec at 10 counts, if the counter is incremented at 9, 8, 7, 6, 5 counts, 0.9 μsec, 0.8 μsec... A reference clock of .5 μs will be generated. When the data of the basic frequency table 51 shown in FIG. 6 is processed by these reference clocks, 2500, 3075, and 486, respectively.
The same result as setting the acceleration at 7,5100, 6950, 10000 [mm / sec ² ] can be obtained.

{Operation Example} Assume that the CPU 24 creates five sets of control data as shown in FIG. Each of the control data includes a flag 61 indicating whether the address of the basic frequency table 51 is to be increased, decreased, or not increased / decreased, a read start address 62, and repeat data 63 indicating the number of times of reading from the read start address 62; The four data of the clock number 64 indicating the reference clock are one set.
If the first (flag 61) is "0", read 23 without increasing or decreasing the address of the RAM 23a to be referred to,
If “1”, the address is read by increasing the address by one step, and if “2”, the address is read by decreasing the address by one step.

The address of the fundamental frequency table 51 to be read first is specified in the second read start address 62, and is sequentially specified by the third repeat data 63 from the address specified by the address 62. An operation of reading the data of the RAM 23a a certain number of times while changing the address according to the increase / decrease value designated by the first flag 61 is performed. Then, as the data value corresponding to the read address, the reference clock is selected by the fourth clock number 64, and the pulse period for driving the motor is determined.

In the example shown in FIG. 7, the clock number 64 = 1
, A reference clock of 1 μsec is selected, and when the clock number 64 = 4, a reference clock of 0.7 μsec is selected. If the clock number 64 = 0, the reference clock selected by the previous clock number 64 is used as it is. After one set of command data 61 to 64 is processed, the next set of command data 61 to 64 is processed continuously, but when the command data 61 to 64 does not exist, the processing of the ASIC 23 ends. And

Internal RAM 23a referred to by ASIC 23
When the data value of the basic frequency table 51 shown in FIG. 6 is written in advance, the CPU 23 outputs 4 × 5 sets = 20 pieces of control data as shown in FIG.
Only by sending the start signal to the SIC 23, the first
Acceleration 5100 [mm] according to the control data 61 to 64 of the set
/ sec ² ] at a linear velocity of 118 mm / sec and acceleration 2500 [mm / sec ² ] according to the second set of control data 61 to 64.
Accelerates the linear velocity to 150 mm / sec. In addition, according to the third set of control data 61 to 64, the constant linear velocity = 150 mm / sec.
By moving a distance of 5 mm, the fourth and fifth control data 61
As a result, the speed is reduced in the direction opposite to the accelerated first and second profiles.

In this example, when the ASIC 23 has advanced a distance of 100 mm as a whole, the processing of the ASIC 23 ends, and the motor 21 stops. However, the first flag 51 of each control data is set to "3" and "3". In the case of "4", by reading the address while increasing the address while rotating the motor 21 in the reverse direction and by reading the address while decreasing the address while rotating the motor 21 in the reverse direction, the advanced motor 21 can be arbitrarily retracted. . That is, even if control data for instructing all forward and backward operations is transmitted to the ASIC 23, in this example, the data amount is only 40 pieces. Further, by changing the read start address 62 specified by each control data and the reference clock 64 to be used, one drive profile in which the acceleration is sequentially changed can be set without rewriting the data in the RAM 23a. Becomes possible.

In this example, two sets of control data used for acceleration and deceleration are set. However, as shown in FIG. 8, the number of tables is further increased to change the address 62 to be referred or the reference clock 64 to be used. By
It is possible to set a drive pattern with a smoother acceleration / deceleration profile. Even in this case, the number of data to be transmitted to the ASIC 23 can be kept very small because the number of data only increases for each one of the increased control data. Further, by performing such control, it is possible to easily set the acceleration profile of the curved pattern 71 as shown in FIG. 5 of the first embodiment as the acceleration profile 72 approximated by a smooth straight line. Become.

Also, as shown in the example, since one drive pattern is a combination of control data having a small capacity, even if all combinations of drive patterns under different conditions are collected, the required storage area is small. I'm done. For this reason, by storing control data in which each processing condition 81 such as a scaling factor as shown in FIG. 8 is further indexed in the main memory (RAM 25), complicated recalculation by the CPU 24 even when the driving condition changes. Without transmitting the drive data,
Since the amount of data to be transmitted is small, the processing time and processing load of the CPU 24 can be reduced.

[0049]

As described above, according to the first aspect of the present invention, the necessary frequency data to be stored in the storage unit for accelerating the motor is only for the basic acceleration, and for the other accelerations. Since it is obtained by thinning out the basic frequency data, the storage capacity of the RAM for storing the frequency data can be reduced, and the processing time and processing load of the CPU can be reduced.

According to the second aspect of the present invention, the fundamental frequency data is stored in the RAM of the motor driving IC for controlling the motor.
The processing for thinning out data is also performed by the motor drive IC, so that even if the acceleration profile or the set speed is changed, the processing load on the CPU does not increase.

According to the third aspect of the present invention, since the thinning value of the data to be set in the motor drive IC is set in the control table in advance, it is possible to sequentially change the acceleration. This makes it possible to obtain an acceleration profile that approximates an acceleration curve with a smooth straight line without performing complicated calculation processing and data transfer processing on the CPU side.

According to the fourth aspect of the present invention, since the control table data for generating the acceleration profile has only a very small amount of data as compared with the actual frequency data, it is transferred from the CPU to the motor drive IC. Processing load can be reduced.

Further, according to the fifth aspect of the present invention, since the data amount of the control table is small, it is possible to store the control table data at all magnifications in the RAM on the CPU side. Therefore, even if the set speed changes, the control table can be transferred to the motor drive IC without performing complicated calculation processing by the CPU.
The program processing of the CPU is reduced.

According to the sixth aspect of the present invention, the necessary frequency data to be stored for accelerating the motor is only for the basic acceleration, and for the other accelerations, the reference clock of the ASIC for processing the frequency data. , The storage capacity of the RAM for storing frequency data can be reduced, and the processing time and processing load of the CPU can be reduced.

According to the present invention, the fundamental frequency data is stored in the RAM of the motor drive IC for controlling the motor.
The processing of the reference clock for processing the frequency data is performed by the motor drive IC, so that the processing load on the CPU does not increase even if the acceleration profile or the set speed is changed.

Further, according to the present invention, since the selection of the reference clock to be set in the motor drive IC is set in the control table in advance, it is possible to sequentially change the acceleration. This makes it possible to obtain an acceleration profile that approximates the acceleration curve with a straight line without performing complicated calculation processing and data transfer processing on the CPU side.

According to the ninth aspect of the present invention, since the control table data for generating the acceleration profile has only a very small amount of data as compared with the actual frequency data, it is transferred from the CPU to the motor drive IC. Processing load can be reduced.

Further, according to the tenth aspect of the present invention, since the data amount of the control table is small, it is possible to store the control table data at all magnifications in the RAM on the CPU side. Therefore, even if the set speed changes, the control table can be transferred to the motor drive IC without performing complicated calculation processing by the CPU, and the program processing of the CPU is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a motor drive device according to the present invention.

FIG. 2 is an explanatory diagram showing a basic frequency table and another frequency table.

FIG. 3 is an explanatory diagram showing a control table of a RAM on a CPU side in FIG. 1;

FIG. 4 is an explanatory diagram illustrating a driving example of the motor driving device of FIG. 1;

FIG. 5 is an explanatory diagram illustrating an acceleration profile of the motor drive device of FIG. 1;

FIG. 6 is an explanatory diagram showing a fundamental frequency table and another frequency table in the second embodiment.

FIG. 7 is an explanatory diagram illustrating a control table of a RAM on a CPU side according to a second embodiment.

FIG. 8 is an explanatory diagram illustrating a control table of a RAM on a CPU side according to the second embodiment.

FIG. 9 is a block diagram showing a conventional motor driving device.

FIG. 10 is an explanatory diagram showing various acceleration profiles.

FIG. 11 is an explanatory diagram showing vibration due to acceleration.

[Explanation of symbols]

 Reference Signs List 21 motor 22 motor drive circuit 23 motor control ASIC 23a built-in RAM 24 CPU 25 RAM

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA23 DA41 ED04 EE01 EE03 EE04 EE07 EE08 FA06 5B047 AA01 BA02 BC14 CA08 CB07 CB10 CB17 EA01 EB12 5C072 AA01 BA02 MB02 UA11 UA13 XA01 5H580 AA04 FA14

Claims (10)

[Claims] 1. A motor drive device for controlling the number of rotations of a motor based on frequency data of a driving pulse of the motor, wherein a basic frequency data corresponding to the basic number of rotations of the motor stores a basic frequency table corresponding to each address. And a means for thinning out frequency data of the basic frequency table in accordance with the number of rotations of the motor to be controlled and reading out the data as drive pulse frequency data of the motor. 2. The motor drive device according to claim 1, further comprising: a CPU; and a motor drive IC including a storage unit, wherein the CPU stores the basic frequency table in a storage unit in the motor drive IC. Transferring and storing the data, setting the thinning data corresponding to the number of rotations of the motor to be controlled from the CPU to the motor driving IC, and setting the motor driving IC according to the thinning data instructed by the CPU; A motor drive device, wherein frequency data of a frequency table is thinned out and read as frequency data of a drive pulse of the motor. 3. The motor driving device according to claim 1, wherein the number of rotations of the motor is changed by changing a thinning number of the frequency data. 4. A second storage means for storing a control table in which the number of rotations of the motor to be controlled, the frequency data decimation number and the decimation end address correspond to each other, and wherein the CPU has a control table of the second storage means. Is transferred to the motor drive IC, and the motor drive IC thins out frequency data of the fundamental frequency table based on the plurality of control data and reads out the data. The motor drive device according to claim 2, wherein the number of rotations is controlled. 5. The motor driving device according to claim 1, wherein the motor is a motor for driving a scanner, and the scanner reads a document at a different magnification according to the number of rotations thereof. The table is configured by using a scaling factor corresponding to the number of rotations of the motor to be controlled as an index, and the CPU sets the thinning number and the thinning end address of the frequency data according to the designated scaling factor in the second.
5. The motor driving device according to claim 4, wherein said motor driving IC is read out from said storage means to instruct said motor driving IC. 6. A motor drive device for controlling the number of rotations of a motor based on frequency data of a driving pulse of the motor. Means for reading the frequency data of the basic frequency table as frequency data of drive pulses for the motor at different clock frequencies according to the number of rotations of the motor to be controlled, and for driving the motor. Motor drive device. 7. The motor drive device according to claim 6, further comprising a CPU and a motor drive IC having a storage unit built therein, wherein the CPU stores the basic frequency table in a storage unit in the motor drive IC. Transfer and store the clock frequency data in accordance with the number of rotations of the motor to be controlled from the CPU to the motor drive IC, and the motor drive IC responds to the clock frequency data instructed by the CPU. A motor driving device, wherein frequency data of the basic frequency table is read at a clock frequency to drive the motor. 8. The motor driving device according to claim 6, wherein the number of rotations of the motor is changed by changing the clock frequency. 9. A second storage means for storing a control table in which the number of rotations of the motor to be controlled, the read start address of the basic frequency table, the number of reads, and the clock frequency correspond to each other. A plurality of control data in a control table of a storage unit is transferred to the motor drive IC, and the motor drive IC reads out frequency data of the basic frequency table based on the plurality of control data, thereby obtaining a linearly approximated acceleration profile. 8. The number of rotations of the motor is controlled by the controller.
Or the motor drive device according to 8. 10. A motor driving device, wherein the motor is a motor for driving a scanner, and the scanner reads a document at a different magnification according to the number of rotations thereof, and wherein the control is stored in the second storage means. The table is configured by using an index corresponding to a scaling factor corresponding to the number of rotations of the motor to be controlled, and the CPU reads the read start address, the number of times of reading, and the clock frequency according to the designated scaling factor from the second storage unit. 10. The motor drive device according to claim 9, wherein an instruction is given to the motor drive IC.