JP2000184765A - Motor controller and gain regulation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To totally regulate fluctuation in the coefficients (r, q, K, R) related to the performance of load in the angular speed control of a DC motor. SOLUTION: The flow rate Q of the oil delivered from a pump P can be represented by Q=q(VE-Rr'E2(i')/r)/2πK, using the detection value i'(=δ/r') of a detector 109 for detecting a current (i) flowing through a resistor 110 having a shunt resistance (r). In the formula, (q) is the delivery flow rate per signal revolution of the motor pump P, VE is the effective value of a voltage applied to the motor M, R is the armature resistance of the motor M, (r') is reciprocal of the gain of the current detector 109, E2 is a function for calculating the time average (effective value) of the (i'), and K is the armature constant of the motor M. Since the Q is linear expression of E2 (i') when the VE is kept constant, the gains (a), (b) in the expression Q=a(VE-bE2(i')) can be determined definitely by measuring the value of Q for E2 (i').

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 for controlling an angular velocity of a motor to a desired target value without using an encoder, a tachometer (rotation speed sensor), etc.
The present invention relates to a gain adjustment method for adjusting the magnitude of a predetermined input signal of the motor control device before shipping the motor control device. The present invention can be applied to, for example, a motor control device of a vehicle equipped with a power steering system.

[0002]

2. Description of the Related Art A motor controller for measuring or estimating an angular velocity Ω [rad / sec] of a motor or a related value without using a tachometer or the like, and controlling the angular velocity Ω of the motor to a desired value based on this value. Can be considered. For example, in the case of a shunt type DC motor, an ECU (electronic control device) 100 of the DC motor drive system 1 illustrated in FIG. 1 may be considered as a motor control device that performs such angular velocity control. In such an electronic control unit, the oil discharge flow rate Q of the electric pump P driven by the motor M
[Cc / sec] is a desired target value Q _n determined based on a command value (= f (u): u is a command value, f is a function)
Can be measured (estimated) using the following equations (1) to (4).

[Number 1] _{Ω = (V E -RI E)} / K (1)

[Number 2] Q = qΩ / 2π = q ( V E -RI E) / 2πK (2)

V _E = E ₁ (V _a ) (3)

## EQU4 ## I_E= E_Two(I ′) (4) where Ω [rad / sec] is the angle of the motor M
Speed, V_E[V] is the effective value of the voltage applied to the motor M, I
_E[A] is the effective value of the DC current flowing through the motor M, R
[Ω] is the armature resistance value of the motor M, K [V · sec / r
ad] is the armature constant of the motor M, and q [cc / rotation] is
Discharge flow rate per rotation of the dynamic pump P, V _a[V] is
The voltage detected by the voltage detector 107 of the motor M, i ′
[A] is a detection current of the motor M by the current detector 109.
is there. Also, E₁, E_TwoIs the temporary time average of each detected value.
This is a predetermined function for calculating the average (effective value).

In such a DC motor drive system, a shunt resistance value r is connected in series with the current path of the motor M.
A resistor 110 having [Ω] is connected, and both ends (C,
By inputting the potential difference δ [V] of D) to the input terminal of the current detector 109, the load current i flowing through the motor M can be detected. That is, in the ECU 100,
The load current i flowing through the motor M can be detected by the following equation (5).

I ′ = δ / r ′ (5) where r ′ [Ω] is the reciprocal of the gain (conversion coefficient) of the current detector 109, and this value is expressed by
The load current i flowing through the motor M is measured by actually matching the shunt resistance value r [Ω] using a trimming resistor (not shown) provided inside the motor 9. That is, since “i ′ → i” when “r ′ → r”, the detected current i ′ detected by the current detector 109
Is equal to the value of the load current i flowing through the motor M.

[0004]

When the above-described motor control device is used, the angular velocity or its related value (for example, the oil discharge flow rate Q of the electric pump P described above) can be accurately calculated.
[Cc / sec]), the above r,
Although it is necessary to know the values of q, K, and R accurately, it takes time to measure these individually for each product. Therefore, in actuality, each product such as a motor or a pump has It is considered that a method of performing the above calculation using a standard value is general. However, such a method has the following problems. (Problem 1) In order to adjust the variation of r, a trimming resistor (not shown) for adjusting r 'is required inside the current detector 109 as described above, which is disadvantageous in terms of production cost. is there. (Problem 2) Even if the variation in r can be adjusted as described above, the variation in q, K, and R of each system component (motor or pump) cannot be adjusted. (Problem 3) For example, when a vehicle having a power steering system is shipped, if Q has a large variation due to the variation of q, K, and R, even if the vehicle is of the same model (specification), the individual products may have different quality. As a result, large variations occur in the steering force.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to solve the problem of the angular velocity Ω of a motor or its related value (for example, the oil discharge flow rate of the electric pump P described above). Accurate angular speed control is realized by accurately measuring the speed Q, etc., that is, the load performance-related coefficients (r, q, K, R, etc.) of a load interlocking device such as a motor and a pump. It is an object of the present invention to propose a motor control device capable of adjusting the variation of the motor as a whole and a gain adjustment method thereof.

[0006]

In order to solve the above-mentioned problems, the following means are effective. That is, the first means includes a voltage detecting means for detecting a voltage applied to the DC motor, a current detecting means for detecting a current flowing through the motor, and an angular velocity calculating means for calculating an angular velocity of the motor from these voltages and current values. And a command voltage calculating means for inputting an angular velocity value from the angular velocity calculating means and outputting a voltage value to be applied to the motor so that the angular velocity reaches the target speed. Value and
By measuring the related value of the current and the related value of the voltage, the relationship between these related values is determined, and from this relationship, the value of the predetermined coefficient used in the angular velocity calculating means is determined. .

[0007] The second means is the first means, wherein the DC motor is connected to a hydraulic power supply of an automobile.
A motor that drives an electric pump that supplies oil to the steering gear, a motor that drives an electric pump, the related value of the above angular velocity is the flow rate of oil discharged by the pump, and the related value of the above current is a shunt resistor connected in series with the motor. The time-average value of the potential difference between both ends of the container, and the related value of the above voltage is the time-average value of the voltage applied to the motor.

[0008] The third means may be the first or second means.
In the means, the related value of the angular velocity is determined as a linear function of the related value of the current or the linear function of the related value of the voltage by measuring the above related values, and the coefficient of the independent variable of the linear function is obtained. And determining the gain for the voltage value detected by the voltage detecting means and the gain for the current value detected by the current detecting means from the value of the constant term.

A fourth means is a motor control device having a voltage detection means for detecting a voltage applied to a DC motor, wherein the current detection means for detecting a current flowing in the motor and a measurement relating to the present motor control apparatus. Was
Gain-related value storage means for storing a predetermined coefficient, gain or a related value determined from a relationship between a related value of an angular velocity of the motor, a related value of a current flowing through the motor, and a related value of a voltage applied to the motor; And a predetermined coefficient, gain or related value from the gain related value storage means, and an angular velocity for calculating the angular velocity of the motor from the input information and the voltage and current values detected by the voltage detecting means and the current detecting means. And a command voltage calculating means for inputting a value of the angular velocity of the motor from the angular velocity calculating means and outputting a voltage value to be applied to the motor so that the angular velocity reaches the target speed.

A fifth means is the fourth means, wherein the DC motor is a motor for driving an electric pump for supplying oil to a hydraulic power steering gear of the vehicle, and the related value of angular velocity is provided. Is the flow rate of oil discharged from the pump, the related value of the current is the time average of the potential difference across the shunt resistor connected in series with the motor, and the related value of the voltage is the time average of the voltage applied to the motor. It is to be. With the above means, the above-mentioned problem can be solved.

[0011]

According to the above-described means, the motor control device measures the related value of the angular velocity of the motor, the related value of the current, and the related value of the voltage so that the related value between the related values is measured. When the relationship is obtained and the value of the predetermined coefficient used in the angular velocity calculating means is determined from this relationship, the same result as when the load performance related coefficients (r, q, K, R, etc.) are individually measured is obtained. Therefore, it is possible to adjust the variation in the load performance-related coefficients (r, q, K, R, etc.) as a whole. More specifically, this will be described in the following examples.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on specific embodiments. (First Embodiment) As described above, FIG. 1 shows a system configuration diagram of a DC motor drive system 1 to which the gain adjustment method according to the present invention can be applied. The present system 1 is mounted as a motor control device in a power steering system of an automobile. An electric pump P for supplying oil to a hydraulic gear of a power steering system is driven by a brushed DC motor M using a permanent magnet having a shunt characteristic. The DC motor M is driven by being supplied with power from a DC drive power supply (power supply voltage V _CC ). The DC supply power is controlled by chopper control using an electronic control switch SW composed of a PMOS, a PMOS drive circuit 108, and a PWM converter 105.

The CPU 101 has a ROM 102 and a RAM
Using the value stored on the 103, to calculate the value V _n of the command voltage to be outputted to the PWM converter 105 (voltage to be applied to the motor M). The CPU 101 calculates the vehicle speed u [m / sec] necessary for this calculation from a vehicle speed meter (not shown), the measured voltage V _a [V] (temporary maximum value) of the motor M, and the load current i [ A] with the A / D converter 104
And from the A / D converter 106. C
PU101 is, PWM converter 1 the value of the calculation result V _n
Output to 05. The voltage detector 107 detects the voltage V _a (temporary maximum value) of the motor M and outputs the voltage V _a to the A / D converter 104.
Output to

On the lower voltage side (0 earth side) of the electronic control switch SW, a resistor 1 having a shunt resistance r [Ω] is provided.
10 are connected in series (on the motor current path) to the motor current path. The negative terminal of the current detector 109 is connected to the lower voltage side of the resistor 110, and the positive terminal of the current detector 109 is connected to the upper voltage side.
The current detector 109 calculates the potential difference δ between both ends of the resistor 110.
By inputting [V], the load current i [A] (= δ
[V] / r [Ω]), and the A / D converter 106
Output to

However, in the present invention, since the conventional adjustment by the trimming resistor which guarantees r '= r (that is, i' = i) is not performed, generally, r '、 r. In fact, strictly speaking, the current detector 109 is
By inputting the potential difference δ [V] between both ends of the resistor 110, the detection current i ′ [A] (= δ [V] / r ′ [Ω])
Is output to the A / D converter 106. Therefore, (4)
Can be written as in the following equation (6) in the present invention.

I _E = E ₂ (i ′) / μ (6) where,

Μ≡r / r ′ (7) If (6) and (7) are used, (2) becomes

[Equation 8] _{Q = q (V E -RE 2} (i)) / 2πK = a (V E -bE 2 (i ')) can be written as (8). However, here:

A≡q / 2πK (9) is a gain (amplification factor) with respect to the voltage (V _E −bE ₂ (i ′)) when obtaining Q;

B≡R / μ (10) is a gain (amplification factor) with respect to the current E ₂ (i ′) when obtaining Q.

Power supply voltage V_CCAnd in chopper control
Duty ratio λ (or command voltage V _n) To a constant value
If fixed, then (8) is V_ETakes a certain value
E _TwoIt becomes a linear expression for (i '). That is,

Q = −αE ₂ (i ′) + Q ₀ (11) where:

Α≡ab (12) is the absolute value of the slope of the linear equation (11),

Q ₀ １３aV _E (13) is the intercept of the vertical axis of the linear equation (11).

FIG. 2 shows the structure of the DC motor drive system 1.
Flow rate Q of oil discharged from pump P and DC motor
The measured value E of the load current of M_Two(I ') and the effective value i'E
3 shows a graph representing a correlation. This graph uses the above method
By V_EIs fixed to 10 [V], and E_Two(I ')
Is actually measured. However,
E_TwoThe measurement of (i ') has the same gain as that of the current detector 109.
(1 / r ') and ammeter with time averaging function
And the effective value of the current between the CDs (temporary average value) E _Two(Δ
/ R '). Also, V_EValue (= 10 [V])
Similarly, a voltmeter with a time averaging function
Measure the effective value (temporary average) of the voltage. like this
Measurement can be performed for each DC motor drive system 1
For example, for each DC motor drive system 1,
According to (14) and (15), the above-mentioned gains a and b are concretely set.
Can be determined.

A = Q ₀ / V _E (14)

B = α / a = αV _E / Q ₀ (15)

According to such a method, r, q, K, R
Can be adjusted for each DC motor drive system without having to directly determine the values of these values. The values of the gains a and b are
If stored in the ROM 102 (the gain-related value storage means), the command voltage calculation means can effectively use the information as described below.

FIG. 3 is a flowchart of a command voltage calculation routine (command voltage calculation means) executed by the CPU 101 using the values of the gains a and b stored in the ROM 102. In this routine, first, in step 310, gain a required for calculating the command voltage V _n, from ROM102 numbers for the b, read on RAM 103. Next, in step 320, the value of the duty ratio λ in the chopper control is provisionally determined. As the initial value, an appropriate value that satisfies “0 ≦ λ ≦ 1” may be empirically selected. In step 330, the vehicle speed u
[M / sec], the measured voltage V _a [V] of the motor M,
The detected current i '[A] is input from a vehicle speedometer (not shown), an A / D converter 104, and an A / D converter 106, respectively.

In step 340, the command value Q _n of the discharge flow per unit time of the pump P is calculated by the following equation (16).
[Cc / sec] is calculated.

Q _n = f (u) (16) where f is a function empirically obtained from the situation that the steering assist torque is required as the vehicle speed u becomes lower. is there.

In step 350, the current discharge flow rate Q of the pump P per unit time is calculated from (3) and (8). However, in this routine, the functions E ₁ , E
₂ uses the one defined as follows.

V _E = E ₁ (V _a ) ≡λV _a (17)

I _E = E ₂ (i ′) ≡ (Σ ^J _{k = 1} i ′ _k ) / J (18) Here, J is an appropriate sampling number for calculating a time average (effective value). , I ′ _k are the detected currents i ′ [A] detected at every microscopic sampling time interval.

[0022] At step 360, than the value of (Q _n -Q), according to the following equation (19), calculates a command voltage V _n.

V _n = g (Q _n −Q) (19) where g is a predetermined coefficient. Step 37
In 0, it outputs the value of the operation result V _n on the PWM converter 105.

In step 380, the value of the duty ratio λ is calculated again according to the following equation (20).

The value of the number 20 _{λ = V n / V CC (} 20) This lambda is the average value V _E of the motor voltage to the next (1
It is intended to be used when determining according to 7). However, in the DC motor drive system 1, R≫r.

The desired angular velocity control can be realized by continuously and repeatedly executing the above processing.
That is, according to the present embodiment, in the power steering system of an automobile, it is possible to supply a stable and constant flow of oil to the hydraulic gear in accordance with the vehicle speed u. It is possible to provide a power steering system with a stable steering feel.

Further, since the gains a and b are values that are optimally adjusted for each vehicle, the above-described problem that the steering force has a large variation in each vehicle does not occur. In addition, there is no need to actually perform adjustment using a physical trimming resistor, which has been conventionally performed. Further, according to the present embodiment, since the respective values of r, q, K, and R can be adjusted without providing the trimming resistor (not shown) in the current detector 109, the trimming resistor is used as the current detector 109. It is possible to use a device without a built-in device, which is advantageous in terms of production cost.

(Second Embodiment) FIG. 4 shows a system configuration diagram of a DC motor drive system 2 to which the gain adjustment method of this embodiment is applied. The DC motor drive system 2 is mounted as a motor control device in a power steering system of an automobile. The system 2 is mounted on a power steering system that directly connects and drives a motor so that an assist torque is directly applied to a power steering shaft and a power steering gear without passing through a hydraulic mechanism. Things.
Therefore, in the second embodiment, the pump P is connected to the motor M.
Is not connected.

The ECU 400 of the present system 2 is very similar to the ECU 100 of the first embodiment.
It is different from the ECU 100. (Difference 1) Instead of the current detector 109, a voltage detector 111 is connected to both ends (C, D) of the resistor 110, and the voltage detector 111 has a potential difference δ between CDs.
[V] is output to the A / D converter 106. CPU10 such as effective value V _E of (difference 2) motor voltage
1 handles the physical quantities handled by the interface 120 in real time.
Can be monitored from the input / output device 130 via the. Note that the input / output device 130 may be a device that can be connected to the interface 120 and that can be easily attached and detached only when performing this monitoring.

In the present system 2, (1), (3)
And, according to the following equation (21), the angular velocity Ω [ra
d / sec].

I _E = E ₂ (i) = E ₂ (δ / r) = δ _E / r (21) where i [A] is a load current flowing through the motor M as described above, r [Ω] is the shunt resistance value of the resistor 110, and δ _E is the same as the calculation in the above (4).
This is an average value calculated by the PU 101 and defined by the following equation (22).

Δ _E ≡E ₂ (δ) (22)

The expression (1) can be rewritten as the following expression (23) by using the expressions (21) and (22).

[Number 23] _{Ω = (V E -Rδ E /} r) / K = c (V E -dδ E) (23) However, here,

C≡1 / K (24) is a gain (amplification factor) with respect to the voltage (V _E −dδ _E ) when obtaining Ω;

D≡R / r (25) is a gain (amplification rate) with respect to the potential difference δ _E when obtaining Ω.

[0030] Therefore, as in the first embodiment, if secure the V _E to a constant value, at that time (23) is a linear equation. That is,

Ω = −βδ _E + Ω ₀ (26) where,

Β≡cd (27) is the absolute value of the slope of the linear equation (26),

Ω ₀ ≡cV _E (28) is the intercept of the vertical axis of the linear equation (26).

FIG. 5 is a graph showing the correlation between the angular velocity Ω of the motor M in the DC motor drive system 2 and the temporary average value (effective value) δ _E [V] of the potential difference between the CDs. This graph, the value of V _E by the above method 10
The value of Ω with respect to δ _E was actually measured while fixing to [V].

However, the measurement of V _E and δ _E is performed by monitoring the calculation result of the CPU 101 from the input / output device 130 in real time, and the measurement of Ω is a tachometer (not shown) dedicated to the main measurement (for gain adjustment). This is performed using If such a measurement is performed for each DC motor drive system 2, the gains c and d can be specifically determined for each DC motor drive system 2 by the following equations (29) and (30). it can.

C = Ω ₀ / V _E (29)

D = β / c = βV _E / Ω ₀ (30)

According to such a method, the same operation and effect as in the first embodiment can be obtained. Also, V _E , δ _E
Is measured in real time from the input / output device 130 by the CPU.
Since it can be implemented by monitoring the calculation result of 101, there is no need to prepare a voltmeter or an ammeter, and further, according to this method, there is no measurement error when measuring using a voltmeter or an ammeter. There is also an effect that there is no room to do so.

Third Embodiment In the DC motor drive system 1 shown in FIG. 1, if the magnitude of the mechanical load applied to the motor M and the voltage applied to the motor M are adjusted, the value of the load current flowing through the motor M can be reduced. Macroscopically, it can be kept constant. Therefore, at this time, the average value E ₂ (i ′) of the current i ′ detected by the current detector 109 is also kept constant. FIG.
Is the flow rate Q of the oil discharged from the pump P and the DC current when the average value E ₂ (i ′) of the detected current i ′ is fixed to 2 [A] in the DC motor drive system 1 by this method. is a graph showing the correlation between the effective value V _E of the voltage of the motor M.

The equations in this graph are (8), (9),
From (10),

Q = a (V _E −bE ₂ (i ′)) = a (V _E −V ₀ ) (31)

V ₀ ≡bE ₂ (i ′) (32)

Therefore, the above-mentioned gain a coincides with the value of the slope of this graph. Also, the gain b is from intercept V ₀ which horizontal axis of the graph can be obtained as shown in the following equation (33).

B = V ₀ / E ₂ (i ′) (33) The gains a and b can be determined by such a method. Therefore, according to this method, the same operation and effect as those of the first embodiment can be obtained.

In the above embodiment, the gains a and b or c and d are obtained by manual calculation. For example, the tachometer for gain adjustment in the second embodiment may be replaced by an angular velocity for gain adjustment. At the time of measurement, if directly connected to the ECU, C
The PU 101 can also automatically perform the measurement for determining the gain, the calculation of the gain value, and the storage of the gain. That is, these series of procedures can be consistently automated by a program.

Further, in the above embodiment, the means of the present invention is used in the power steering system of an automobile. However, the present invention reduces the rotational speed of a brushed DC motor using a permanent magnet. It can be used for general DC motor angular velocity control performed to maintain a constant regardless of the magnitude of the load applied to the motor.

Further, even when a shunt motor having a shunt excitation winding instead of a permanent magnet is used as the DC motor, the operation and effects of the present invention can be obtained by applying the present invention. .

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a DC motor drive system 1 to which a gain adjustment method according to the present invention can be applied.

FIG. 2 is a graph showing a correlation between a flow rate Q of oil discharged from a pump P in a DC motor drive system 1 and an effective value i′E of a measured value E ₂ (i ′) of a load current of the DC motor M; .

FIG. 3 shows a CPU 10 in the DC motor drive system 1.
3 is a flowchart of a command voltage calculation routine executed by the first embodiment.

FIG. 4 is a system configuration diagram of a DC motor drive system 2 to which a gain adjustment method according to the present invention can be applied.

FIG. 5 is a diagram showing the difference between the angular velocity Ω of the DC motor M and the potential difference (effective value) δ _{E of the} shunt resistor in the DC motor drive system 2.
The graph showing the correlation with.

Figure 6 is a graph representing the correlation between the effective value V _E of the voltage of the flow rate Q and the DC motor M of oil discharged from the pump P in the DC motor drive system 1.

[Explanation of symbols]

Q: Oil discharge flow rate of the electric pump P [cc /
sec] a... Gain (amplification rate) with respect to voltage when obtaining Q. b... Gain (amplification rate) with respect to current when obtaining Q. q ... Discharge flow rate per rotation of electric pump P [cc / rotation]. Omega ... effective value [a] an armature resistance of R ... motor M of the angular velocity [rad / sec] V _E ... effective value of the voltage applied to the motor M (V) I _E ... DC current flowing through the motor M of the motor M [ Ω] K ... Armature constant of motor M [V · sec / ra
d] V _a ... voltage difference [V] i across the detector 107 shunt resistance value possessed by the detected voltage [V] r ... resistor 110 of the motor M by [Ω] [delta] ... resistor 110 (between CD) '... function for calculating a time average of the function E ₂ ... i 'for calculating the time average of the detected current [a] E ₁ ... V _a of the motor M by the current detector 109

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H571 AA03 BB07 CC01 DD02 GG02 GG04 GG05 HA01 HA09 HB01 JJ03 JJ16 JJ17 KK06 LL01 LL22 LL23

Claims (5)

[Claims] A voltage detecting means for detecting a voltage applied to a DC motor; a current detecting means for detecting a current flowing through the motor; an angular velocity calculating means for calculating an angular velocity of the motor from the voltage and the value of the current; And a command voltage calculating means for inputting the value of the angular velocity from the angular velocity calculating means and outputting a value of a voltage to be applied to the motor so that the angular velocity reaches a target speed. By measuring the related value of the angular velocity, the related value of the current, and the related value of the voltage, a relationship between the related values is determined, and the predetermined value used in the angular velocity calculating means is determined. Wherein the value of the coefficient is determined from the relationship. 2. The motor for driving an electric pump for supplying oil to a hydraulic power steering gear of an automobile, wherein the DC motor has a related value of the angular velocity, and a flow rate of oil discharged from the pump. Speed, the current related value is a time average value of a potential difference between both ends of a shunt resistor connected in series to the motor, and the voltage related value is a time average value of a voltage applied to the motor. 2. The gain adjustment method according to claim 1, wherein: 3. The method according to claim 1, wherein the related value of the angular velocity is obtained as a linear function of a related value of the current or a linear function of a related value of the voltage, and a coefficient of an independent variable of the linear function and The gain according to claim 1, wherein a gain for the voltage value detected by the voltage detection unit and a gain for the current value detected by the current detection unit are determined from a value of the constant term. Adjustment method. 4. A motor control device having voltage detection means for detecting a voltage applied to a DC motor, wherein the current detection means detects a current flowing in the motor; and Gain-related-value storage means for storing a predetermined coefficient, gain or a related value determined from a relationship among a related value of an angular velocity of the motor, a related value of the current, and a related value of the voltage; The coefficient, the gain or the related value is inputted from the related value storage means, and the angular velocity for calculating the angular velocity of the motor from the input information and the voltage and current values detected by the voltage detecting means and the current detecting means. Calculating means for inputting the value of the angular velocity from the angular velocity calculating means and outputting a voltage value to be applied to the motor so that the angular velocity reaches a target speed; Motor control device characterized by having a calculating means. 5. The motor for driving an electric pump for supplying oil to a hydraulic power steering gear of an automobile, wherein the DC motor has a related value of the angular velocity, and a flow rate of the oil discharged from the pump. Speed, the current related value is a time average value of a potential difference between both ends of a shunt resistor connected in series to the motor, and the voltage related value is a time average value of a voltage applied to the motor. The motor control device according to claim 4, wherein: