JPH1127981A - Motor drive control device - Google Patents

Abstract

(57) [Summary] [Object] To provide a motor drive control device that corrects a torque constant according to a rotational drive position of a motor. [Structure] As a structure of a motor drive control device in which a torque constant is used as a factor for obtaining a drive current of a motor, a motor, position detection means for detecting a rotation position of the motor, and signals from the position detection means are counted. An arithmetic unit for obtaining an approximate expression of a plurality of straight lines according to the count value and a torque constant calculating unit for obtaining a torque constant based on the approximate expression obtained by the arithmetic unit are provided. Then, the torque constant obtained by the torque constant calculation means is used as a filter for obtaining the drive current of the motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive control device for controlling the drive of a motor while correcting a torque constant that varies according to the rotational drive position of the motor, and more particularly to a drive control device for a one-phase electromagnetic motor. The present invention relates to a motor drive control device.

[0002]

2. Description of the Related Art Conventionally, in a drive control device for a one-phase electromagnetic motor, a torque constant used as a control parameter is often fixed to a certain torque constant parameter.

[0003]

When a one-phase electromagnetic motor is controlled, its torque constant is indispensable as a known parameter, and a deviation in this parameter causes loss of stability of the control system. , Resulting in deterioration of the settability. When the torque constant used as a control parameter is fixed to a certain torque constant parameter, the torque constant of a single-phase electromagnetic motor greatly changes depending on the drive position. Was greatly shifted. In such a case, the stability of the control is lost, so that the driving range for use is limited.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a motor drive control device in which the torque constant is corrected according to the rotational drive position of the motor.

Another object of the present invention is to provide a motor drive control device which ensures the control stability of a one-phase electromagnetic motor.

[0006]

In order to achieve the above-mentioned object, the present invention provides a motor drive control device in which a torque constant is used as a factor for obtaining a drive current of the motor. , A calculating means for counting signals from the position detecting means, and calculating an approximate expression of a plurality of straight lines in accordance with the count value, and calculating the torque constant by the approximate expression obtained by the calculating means. And a torque constant calculating means for obtaining the motor driving control device, wherein the torque constant obtained by the torque constant calculating means is used as a factor for obtaining a driving current of the motor.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a rotation positioning mechanism in a one-phase electromagnetic motor drive control device of Embodiment 1 of the present invention. In FIG. 1, 1 is a one-phase electromagnetic motor, 2 is a rotation angle of the motor, 3 is a rotation angle detection mechanism, 4
Is a rotation angle signal from a rotation angle detection mechanism, 5 is an arithmetic unit, 6 is a motor drive command signal, 7 is a motor drive device, 8
Is the motor drive current.

The rotation angle 2 of the one-phase electromagnetic motor 1 is detected by the rotation angle detection device 3, and the calculation device 5 reads the rotation angle signal 4. A motor drive command signal 6 is calculated by a certain control calculation from the read rotation angle signal 4 and sent to a motor drive device 7, which drives the motor 1 with a motor drive current. At this time, if the torque of the motor 1 is T, the torque constant is Tp, and the motor drive current 8 is I, the following relational expression is established. T = Tp × I In the rotation positioning mechanism as shown in FIG. 1, the one-phase electromagnetic motor 1 has a torque-rotational position curve (characteristic) as shown in FIG.

[0010] Since the torque constant changes depending on the rotational position, a large deviation occurs between the actual torque constant and the torque constant parameter depending on the position. If the relationship between the rotational position and the torque is expressed by a relational expression and is included in the torque constant parameter part of the control calculation, the torque constant parameter can be corrected. However, if this relational expression is too complicated, the calculation time of the arithmetic unit 5 shown in FIG. 1 is slowed down, which adversely affects the control. Therefore, it is desirable to make the relational expression as simple as possible.

FIG. 3 shows an example in which the curve of FIG. 2 is divided into four zones and each is approximated by one straight line. In zone A (0 to +20 degrees), approximation is made with a straight line a, and in zone B (+
20 degrees or more), it is approximated by a straight line b. In the A 'zone (0 degrees to -20 degrees), it is approximated by a straight line a', and in the B 'zone (-2
(Less than 0 degree), it is approximated by a straight line b '. Since the torque rotation position curve in FIG. 2 is symmetrical about 0 degree, the straight lines a and a 'and the straight lines b and b' can be expressed by the same relational expression if the positions are set to absolute values. According to this approximation method,
In the range of −35 ° to + 35 °, a simple calculation of one absolute value conversion, one conditional branch, and a linear expression gives a torque constant parameter substantially equal to the actual torque constant to the control calculation. be able to.

FIG. 4 shows an example of a specific circuit of the arithmetic unit 5 shown in FIG. 1. Reference numeral 51 denotes a CPU.
A logical operation circuit is composed of the RAM 51, the ROM 52, and the RAM 53. Reference numeral 54 denotes a counter to which the rotation angle signal 4 is input, and reference numeral 55 denotes an output unit that outputs a motor drive command signal to the motor drive device 7.

The arithmetic processing operation of the arithmetic unit 5 will be described with reference to the flowchart of FIG. First, the rotation angle signal 4 detected by the rotation angle detection mechanism 3 is counted by the counter 54, and the absolute value of the current position of the rotation angle is obtained (step S10). Next, the absolute value of the current position is stored in a predetermined angular position (for example, 2
(A value corresponding to 0 degrees) is determined (step S11). If not, the slope A = L of the approximate expression of the straight line
a, section B = Lb. That is, the value of the first slope La and the value of the first intercept Lb set in advance are used (step S1).
2). If it exceeds in the determination in step S11, the gradient A of the approximate expression of the straight line is set to Ha and the intercept B is set to Hb (step S1).
3). That is, the value Ha of the second slope and the value Hb of the second intercept set in advance are used.

Next, a torque constant correction coefficient kt is calculated from the approximate expression kt = Ax + B (step S14). That is, when the angle position x and the angle position are 0 to 20 degrees, the correction coefficient kt is calculated using the approximate expression kt = Lax + Lb, and when the angle position is 20 degrees or more, the approximate expression kt = Ha
The correction coefficient kt is calculated using x + Hb. Next, using the calculated kt, a torque constant Tp is obtained by an operation of kt × To (step S15).

Next, the current angular position X and the torque constant T
p, the target position Xre stored in each of the registers A, B, and C of the second register of the RAM 53.
f, based on the load amount J on the motor shaft and the control gain K, are output from the output unit 55 as the motor drive command signal 6 to the motor drive device 7 by the arithmetic expression Iref = K × J / Tp × (Xref−X). The motor drive current amount Iref is calculated (step S16).

Next, another example of a specific circuit of the arithmetic unit 5 shown in FIG. 1 will be described with reference to FIG. In FIG. 6, 5a is a counter added from the rotation angle signal 4 from the rotation angle detection mechanism 3, and 5b is a first register for storing a value corresponding to a predetermined angular position of 20 degrees. Reference numeral 5c denotes a comparison operation unit that compares the count value of the counter 5a with the value of the first register 5b. Reference numeral 5d denotes a torque constant calculation unit that calculates a correction coefficient using the slope of an approximate expression of a straight line determined by the calculation result of the comparison calculation unit 5c, and calculates a torque constant Tp by Kt × To. 5e is the target position Xre
f, a second register having a register A, a register B, and a register C in which a load J on the motor shaft and a control gain K are stored, respectively. 5f is a control operation for calculating the motor drive current amount Iref by an arithmetic expression Iref = K × J / Tp × (Xref−X) using the current angular position X from the counter 5a and the torque constant Tp from the torque constant calculator as factors. Department. An output unit 5g outputs the motor drive current amount Iref output from the control calculation unit 5f to the motor drive device 7 as a motor drive command signal 6.

The operation of the arithmetic unit 5 will be described. The rotation angle signal 4 from the rotation angle detection mechanism 3 is applied to the arithmetic unit 5 and counted by the counter 5a. This counter 5
The current angular position, which is the count value of a, is compared with the value of the first register 5b corresponding to 20 degrees, which is the predetermined angle, by the comparison operation unit 5c, and based on the comparison operation result of the comparison operation unit 5c. The torque constant Tp is calculated by the torque constant calculator 5d.
Is calculated. In other words, when the current angular position does not exceed 20 degrees, the slope A = La and the intercept B = Lb of the approximate expression of the straight line
The correction coefficient is calculated using the approximate expression t = Lax + Lb, and when the current angular position exceeds 20 degrees, the slope A = Ha and the intercept B = Hb of the linear approximate expression are set, and the approximate expression t = Ha
A correction coefficient is calculated using x + Hb, and Kt × To
To calculate the torque constant Tp.

In the control calculation unit 5f, the current angular position X, which is the count value of the counter 5a, and the torque constant calculation unit 5d
, The torque constant Tp from the second register A,
Target position Xre stored in registers B and C
The motor drive current amount Iref is calculated from f, the load amount J on the motor shaft, and the control gain K according to an arithmetic expression Iref = K × J / Tp × (Xref−X). The motor driving current amount Iref calculated by the control operation unit is equal to the motor driving device 7.
Is output from the output unit 5g as the motor drive designation signal 6.

FIG. 7 shows the case where the torque constant is corrected,
This is the result of actually examining the difference in the step response waveform at each of the 0 °, 35 °, and −35 ° positions without performing. The horizontal axis of each graph is time, the upper rectangular wave shows the time until settling, the lower row is the settling waveform, and the vertical axis is the movement amount. It can be seen that the correction of the torque constant improves the settling property and shortens the settling time.

[0020] Figure 8 shows a structure of a one-phase electromagnetic motor 1 shown in FIG. 1, 1a is a rotor magnet which is magnetized in four _{poles, 1b 1, 1b 2, 1b} 3, 1b 4 is winding And these winding coils 1b ₁ , 1b ₂ , 1
b ₃ and 1b ₄ are continuously connected. Winding coil 1
_{b 1, 1b 2, 1b 3} , the rotor magnet 1a by 1b ₄ is energized to one is driven in one direction, the rotor magnet 1a by being energized the other is intended to be driven in the other direction. The winding coils 1b ₁ and 1b
_2, the motor driving current 8 from 1b _3, 1b ₄ to the motor driving device 7 is energized.

(Embodiment 2) In the rotation positioning mechanism shown in Embodiment 1, when it is desired to more closely approximate the torque rotational position curve as shown in FIG. 2, the number of approximate straight lines may be increased. In general, in the case of a torque rotational position curve symmetrical with respect to the origin as shown in FIG. 2, when approximating by n straight lines, one absolute value conversion and ((n / 2) -1) conditions The correction of the torque constant can be performed by the calculation of the branch and the linear expression.

FIG. 9 shows the second embodiment, in which the number of approximate straight lines is set to six. Zone A (0 to +20 degrees) approximates with a straight line a, Zone B (+20 to 30 degrees) approximates with a straight line b, and Zone C (+30 degrees or more) approximates a straight line c.
Approximation. In the A 'zone (0 degrees to -20 degrees), it is approximated by a straight line a', in the B 'zone (-20 degrees to -30 degrees), it is approximated by a straight line b', and in the C 'zone (-30 degrees or less), it is a straight line. Approximate by c '. At this time, the torque constant is corrected by one absolute value conversion, two conditional branches, and a linear expression.

Next, a description will be given of an arithmetic circuit according to a second embodiment of the present invention. Since a block circuit showing an example of a specific circuit of the arithmetic unit 5 is the same as the block configuration of FIG. Is omitted. The arithmetic processing operation of the arithmetic unit 5 according to the second embodiment will be described with reference to the flowchart of FIG.

First, the rotation angle signal 4 detected by the rotation angle detection mechanism 3 is counted by the counter 54, and the absolute value of the current position of the rotation angle is obtained (step S20). next,
The absolute value of the current position is equal to the first predetermined angular position (RAM 53
(For example, a value corresponding to 20 degrees) stored in the first register (step S21).
If not, the slope A of the approximate expression of the straight line A = La, the intercept B =
Lb. That is, the value of the first slope La and the value of the first intercept Lb set in advance are used. If the angle exceeds the second predetermined angle (for example, 30 degrees), it is determined whether the angle exceeds a second predetermined angle (for example, 30 degrees) (step S23). If not,
It is assumed that the slope of the approximate expression of the straight line is A = Ma, and the intercept B = Mb (step S24). That is, the value Ma of the second inclination set in advance
And the value Mb of the second intercept. If it exceeds in the judgment of step S23, the slope A of the approximate expression of the straight line A = Ha and the intercept B =
Hb (step S25). That is, the value Ha of the third slope and the value Hb of the third intercept set in advance are used.

Next, a torque constant correction coefficient kt is calculated by the approximate expression kt = Ax + B (step S26). That is, when the angle position is 0 to 20 degrees, the approximate expression kt = La
Using x + Lb, the correction coefficient kt is calculated, and the angular position is 2
When the angle is 0 to 30 degrees, the correction coefficient kt is calculated using the approximate expression kt = Max + Mb. When the angle position is 30 degrees or more, the approximate expression kt = Hax + Hb is used to calculate the correction coefficient kt.
Is calculated. Next, using the calculated kt, a torque constant Tp is obtained by an operation of kt × To (step S2).
7).

Next, the current angular position X and the torque constant T
p, the target position Xre stored in each of the registers A, B, and C of the second register of the RAM 53.
f, based on the load amount J on the motor shaft and the control gain K, are output from the output unit 55 as the motor drive command signal 6 to the motor drive device 7 by the arithmetic expression Iref = K × J / Tp × (Xref−X). The motor drive current amount Iref is calculated (step S28).

Next, another example of a specific circuit of the arithmetic unit 5 according to the second embodiment will be described with reference to FIG. FIG. 11 is obtained by adding a third register 5h to the block circuit of FIG.

The operation of the arithmetic unit 5 will be described. The rotation angle signal 4 from the rotation angle detection mechanism 3 is applied to the arithmetic unit 5 and counted by the counter 5a. This counter 5
The value of the first register 5b corresponding to the current angular position, which is the count value of a, 20 degrees, which is the predetermined angle, and the third register 5h, which corresponds to 30 degrees, which is the predetermined angle position,
The value of d is subjected to a comparison operation by the comparison operation unit 5c, and the torque constant calculation unit 5d calculates the torque constant Tp based on the comparison operation result of the comparison operation unit 5c. That is, when the current angular position does not exceed 20 degrees, the slope of the straight line approximation formula is set to A = La, the intercept B = Lb, and the approximation formula t = Lax + Lb.
Is used to calculate a correction coefficient, and the current angular position is 20 degrees to 3 degrees.
In the case of 0 degree, the slope A of the approximate expression of the straight line is A = Ma, and the intercept B is M
b, a correction coefficient is calculated using the approximate expression Kt = Max + Mb, and when the current angular position exceeds 30 degrees, the slope of the linear approximate expression is A = Ha, the intercept B = Hb, and the approximate expression t = H
ax + Hb is used to calculate a correction coefficient, and Kt × T
Calculate the torque constant Tp using o.

In the control operation unit 5f, the current angular position X, which is the count value of the counter 5a, and the torque constant calculation unit 5d
, The torque constant Tp from the second register A,
Based on the target position Xref, the load J on the motor shaft, and the control gain K stored in the registers B and C, respectively, an arithmetic expression Iref = K × J / Tp × (Xref−X)
Is used to calculate the motor drive current amount Iref. The motor drive current amount Iref calculated by the control calculation unit is output from the output unit 5g to the motor drive device 7 as the motor drive designation signal 6.

(Embodiment 3) FIG. 12 is a block diagram showing Embodiment 3 of the present invention. In FIG. 12, reference numerals 1 to 8
Up to this is the rotation positioning mechanism in the one-phase electromagnetic motor drive control device shown in the first embodiment. 9 is rotation position information,
Reference numeral 10 denotes a storage device, and reference numeral 11 denotes torque constant information.
FIG. 13 is a table showing the torque for each angle from the torque-rotational position characteristics in the third embodiment. In the rotation positioning mechanism shown in the first embodiment, torque-rotational position curves as shown in FIG. 2 are summarized in a table as shown in FIG. 13 and stored in the storage device 10 in advance. The arithmetic unit 5 has the rotational position information 9
The torque constant information 11 (torque constant correction coefficient) is obtained by referring to the table of FIG. 13 stored in the storage device 10 from (the absolute value of the rotational position). The torque constant at the rotational position is derived from the storage device 10 and is introduced into the control calculation.

Next, a specific circuit of the arithmetic unit 5 shown in FIG. 12 will be described with reference to FIG. In FIG. 14, 5a
Reference numeral denotes a counter added from the rotation angle signal 4 from the rotation angle detection mechanism 3, and reference numeral 10 denotes a storage device to which the count value of the counter 5a is added as position information and outputs torque constant information Tp according to the position information. 5e is a register A, a register B, and a register C in which the target position Xref, the load J on the motor shaft, and the control gain K are stored, respectively.
Is a second register having 5f is a control operation for calculating the motor drive current amount Iref by an arithmetic expression Iref = K × J / Tp × (Xref−X) using the current angular position X from the counter 5a and the torque constant Tp from the torque constant calculator as factors. Department. An output unit 5g outputs the motor drive current amount Iref output from the control calculation unit to the motor drive device 7 as a motor drive command signal 6.

The operation of the arithmetic unit 5 will be described. The rotation angle signal 4 from the rotation angle detection mechanism 3 is applied to the arithmetic unit 5 and counted by the counter 5a. This counter 5a
Is added to the storage device 10, and the storage device 10 outputs torque constant information Tp corresponding to the position information.

In the control calculation unit 5f, the current angular position X, which is the count value of the counter 5a, the torque Tp from the storage device 10, and the target values stored in the registers A, B, and C of the second register 5e, respectively. Position Xre
The motor drive current amount Iref is calculated from f, the load amount J on the motor shaft, and the control gain K according to an arithmetic expression Iref = K × J / Tp × (Xref−X). The motor driving current amount Iref calculated by the control operation unit is equal to the motor driving device 7.
Is output from the output unit 5g as the motor drive designation signal 6.

Although the motor shown in FIG. 8 is driven within a certain angle range, the motor can be driven to rotate by switching the energization of the winding coil according to the detection of the rotation angle. It is also possible to use the present invention.

In the first to third embodiments, the rotation angle detecting mechanism for detecting the rotation position (rotation angle) of the motor is
Although the rotation angle signal from the rotation angle detection mechanism is described as being of an increment type in which the position is calculated by counting the rotation angle signal using a counter in an arithmetic device, the rotation angle detection mechanism of the present invention is It is not limited to the increment type, but may be an absolute type.

When an absolute type is used, a counter is not required, but a conversion means for obtaining the position represented by the obtained signal may be required in some cases. However, if an absolute type is configured so that a signal can be extracted in a format corresponding to the counter value when a counter is used, a conversion unit is not required.

Further, with respect to the first embodiment, a dedicated rotation angle detecting mechanism for controlling a motor according to the present invention is provided as follows.
When the rotation position detecting mechanism of the absolute type is set to a certain range, for example, −20 ° to + 20 °, the signal is in an “H” (high) state, otherwise the signal is “L” ( If it is configured to be in the state of (low), the comparison operation unit can be omitted. In this case, when the signal is “H”, the slope A = La and the intercept B = Lb of the above-described straight line approximation are directly selected. When the signal is “L”, the approximation of the straight line approximation is obtained. Slope A = Ha, intercept B
= Hb.

In the second embodiment, the same operation as in the first embodiment can be performed. However, in this case, a 2-bit signal is used as the rotational position, and the inclination and intercept of the approximate expression of a straight line are directly obtained from those states. Can be selected.

[0039]

As described in detail above, according to the present invention,
Since the torque constant greatly changes depending on the rotational driving position of the motor, the varying torque constant is derived by an approximate expression according to the rotational driving position of the motor, and the motor driving current amount is used for calculation. , The torque constant can be corrected according to the above, and a high-speed and stable control system can be realized in a wider driving range.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a relationship between a torque and a rotation position of the motor illustrated in FIG. 1;

FIG. 3 is a diagram showing a straight line obtained by dividing the torque characteristic into four zones in FIG. 2 and approximating each of the four zones.

FIG. 4 is a block diagram illustrating an example of a specific circuit of the arithmetic device illustrated in FIG. 1;

FIG. 5 is a flowchart of the operation device shown in FIG. 4;

FIG. 6 is a block diagram illustrating another example of a specific circuit of the arithmetic device illustrated in FIG. 1;

FIG. 7 is a diagram showing a step response waveform when the torque constant is corrected and when it is not corrected.

FIG. 8 is a configuration diagram of the motor shown in FIG. 1;

FIG. 9 is a diagram showing straight lines obtained by dividing torque characteristics into six zones and approximating each according to the second embodiment.

FIG. 10 is a flowchart of a block circuit illustrating an example of a specific circuit of the arithmetic device according to the second embodiment of the present invention.

FIG. 11 is a block diagram illustrating another example of a specific circuit of the arithmetic device according to the second embodiment of the present invention.

FIG. 12 is a block diagram of a motor drive control device according to a third embodiment of the present invention.

FIG. 13 is a diagram illustrating a torque constant for each angle based on the characteristics of the torque and the rotational position of the motor illustrated in FIG. 12;

FIG. 14 is a block diagram illustrating a specific circuit of an arithmetic unit according to the third embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 single-phase electromagnetic motor 3 rotation angle detecting mechanism 5 arithmetic unit 7 motor driving device 10 storage device

Claims (12)

[Claims] 1. A motor drive control device wherein a torque constant is used as a factor for obtaining a drive current of a motor, a motor, position detection means for detecting a rotational position of the motor, and counting of a signal from the position detection means. And calculating means for obtaining an approximate expression of a plurality of straight lines in accordance with the count value; and torque constant calculating means for obtaining a torque constant based on the approximate expression obtained by the calculating means. A motor drive control device, wherein the determined torque constant is used as a factor for determining a drive current of the motor. 2. The motor drive control device according to claim 1, wherein said calculating means includes a counter, and a plurality of approximate expressions obtained by the calculating means are expressed by a plurality of linear expressions, and the plurality of approximate expressions are expressed in accordance with the count value of the counter. A motor drive control device selected from a plurality of primary types. 3. The motor drive control device according to claim 1, wherein said motor is a one-phase electromagnetic motor, said one-phase electromagnetic motor drives a predetermined angle range, and said position detecting means is a one-phase electromagnetic motor. A motor drive control device for detecting an angle. 4. A motor drive control device in which a torque constant is used as a factor for obtaining a drive current of a motor, a motor, position detection means for detecting a rotational position of the motor, and counting of a signal from the position detection means. A counter for storing a value of an amount corresponding to a predetermined rotational position of the motor; a comparison operation for comparing the count value of the counter with the stored value of the register to obtain a plurality of approximate expressions according to the comparison result Means, calculating means for obtaining a plurality of approximate expressions in accordance with the count value, and torque constant calculating means for obtaining a torque constant from the approximate expressions obtained by the comparing and calculating means. A motor drive control device, wherein the determined torque constant is used as a factor for determining a drive current of the motor. 5. The motor drive control device according to claim 4, wherein the register stores first and second values corresponding to first and second predetermined rotational positions of the motor, and the register performs the comparison operation. The motor drive control device is characterized in that the means compares the count value of the counter with first and second stored values of the register. 6. A motor drive control device in which a torque constant is used as a factor for obtaining a drive current of a motor, a motor, position detection means for detecting a rotational position of the motor, and counting of a signal from the position detection means. A counter having a plurality of pieces of torque constant information, and storage means for selecting one piece of torque constant information from the plurality of pieces of torque constant information in accordance with the counter value; and a torque constant selected from the storage means. Is used as a factor for determining the drive current of the motor. 7. The motor drive control device according to claim 6, wherein the storage unit collectively stores a relationship between position information, which is a count value of the counter, and torque constant information in a table, and refers to the table. Wherein the torque constant information according to the count value of the counter is selected. 8. A motor, a position detecting means for detecting a rotational position of the motor and generating a pulse signal for each predetermined rotation angle, a counter for counting pulse signals from the position detecting means, and a predetermined rotational position of the motor. The first to store the value of the amount corresponding to
A comparison operation means for comparing the count value of the counter with the stored value of the first register, and obtaining an approximate expression of a plurality of straight lines according to the comparison result; and an approximation obtained by the comparison operation means. A torque constant calculating means for calculating a torque constant correction coefficient by an equation to obtain a torque constant; a second register for storing a value corresponding to a target rotational position; a torque constant of the torque constant calculating means and the second constant; Means for calculating the amount of drive current of the motor by calculating based on the stored value of the register and the count value of the counter, and the like. 9. The motor drive control device according to claim 8, wherein the second register stores a load amount to the motor shaft and a value corresponding to a control gain, and a drive current amount to the motor. The motor drive control device is characterized in that the means for calculating the load amount and the control gain are calculated. 10. A motor drive control device in which a torque constant is used as a factor for obtaining a drive current of a motor, a motor, position detection means for detecting a rotation position of the motor, and current rotation detected by the position detection means. Judgment means for judging which of the predetermined zones the position falls into; a primary expression determination means for determining the value of the primary slope and the value of the intercept based on the zone determined by the determination means; And a torque constant calculating means for calculating a torque constant based on the linear expression determined by the above and a correction coefficient obtained from the current position by the torque constant correcting means. 11. A motor drive control device in which a torque constant is used as a factor for obtaining a drive current of a motor, comprising: a motor; position detection means for detecting a rotation position of the motor and outputting a signal related to the rotation position; A calculating means for obtaining an approximate expression of a plurality of straight lines in accordance with a signal from the position detecting means; and a torque constant calculating means for obtaining a torque constant based on the approximate expression obtained by the calculating means. A motor drive control device, wherein the torque constant obtained by the calculation means is used as a factor for obtaining a drive current of the motor. 12. A motor drive control device in which a torque constant is used as a factor for obtaining a drive current of a motor, wherein the motor and a plurality of rotational position ranges of the motor are detected and a signal related to the rotational position range is output. Position range detecting means, calculating means for obtaining an approximate expression of a plurality of straight lines according to a signal from the position range detecting means, and torque constant calculating means for obtaining a torque constant from the approximate expression obtained by the calculating means. A motor drive control device, wherein the torque constant calculated by the torque constant calculation means is used as a factor for calculating a motor drive current.