JP2002193122A - Electric power steering control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power steering control device capable of achieving favorable power steering feeling regardless of running status. SOLUTION: An inertia compensation control device 13 calculates a steering torque differential equivalent value by passing a steering torque T given from a phase compensating part I1 through a function set according to the steering status, and generates a steering compensation value ΔI1 according to the calculated steering torque differential equivalent value. The inertia compensating value ΔI1 is added to a basic assist current value I generated by a basic assist control part 12, and a convergent correction value ΔI2 generated by a convergence control part 14 and a return correction value ΔI3 generated by a return control part 15 are added to the above addition value, thereby generating an assist target current value I+ΔI1+ΔI2+ΔI3 to be supplied to the electric motor 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric power steering device that assists steering by using a driving force generated by an electric motor.

[0002]

2. Description of the Related Art In an electric power steering system employing an electric motor as a source of a steering assist force to be applied to a steering mechanism, a controller for the electric power steering system is controlled based on a steering torque and a vehicle speed applied to a steering wheel. The electric motor is controlled. Specifically, detection signals from a torque sensor for detecting a steering torque and a vehicle speed sensor for detecting a vehicle speed are input to the controller, and the controller receives the detection signals from the torque sensor and the vehicle speed sensor. A corresponding target current value is determined, and feedback control of the electric motor is performed based on the target current value.

In this type of electric power steering apparatus, for example, when traveling on a slalom road where a small curve is continuous, a response delay due to inertia of an electric motor or the like (a rise in a steering assist force with respect to a change in steering torque). Delay). When the response delay occurs, the steering wheel is heavy, and the driver feels that the steering of the steering wheel is jammed.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric power steering control device capable of achieving a good steering feeling irrespective of running conditions.

[0005]

According to the first aspect of the present invention, there is provided an electric motor driven based on a steering torque (T) applied to an operating member (1). A control device (10) for an electric power steering device that generates a steering assist force by a motor (4)
A basic assist current generating means (12) for generating a basic assist current value (I) according to the steering torque.
And an inertia compensation control transfer function (G
(S), G1 (s), G2 (s)), and the steering torque is passed to the inertia compensation control transfer function set by the transfer function setting means (134, 135, 101, 111). Steering torque differential equivalent value generating means (131, 11) for generating a steering torque differential equivalent value (δT ′).
2) and an inertia compensation value (ΔI1) based on the steering torque differential equivalent value generated by the steering torque differential equivalent value generating means.
Means for generating inertia compensation current (132, 133)
A target current value generating means (16a) for adding the basic assist current value generated by the basic assist current generating means and the inertia compensation value generated by the inertial compensation current generating means to generate an assist target current value; And a motor driving means (18) for driving the electric motor based on the assist target current value generated by the target current value generation means.

[0006] Alphanumeric characters in parentheses indicate corresponding components in the embodiment described later. Hereinafter, the same applies in this section. According to the present invention, a steering torque derivative equivalent value is generated by passing the steering torque through the inertia compensation control transfer function, and the inertia compensation value is set based on the steering torque derivative equivalent value. As a result, the sense of rigidity of the operating member changes due to a change over time of the electric motor or a change in the tire pressure of the vehicle, so that even if the magnitude of the steering torque applied to the operating member changes, this change is not affected by inertia. Compensation can be made with a compensation value. Therefore, there is no possibility that the steering feeling is deteriorated due to the aging.

Further, since the inertia compensation control transfer function is set based on the traveling condition of the vehicle, the inertia compensation control transfer function is set based on a steering torque differential equivalent value generated through the steering torque in the inertia compensation control transfer function. The value can satisfactorily compensate for a response delay due to inertia of an electric motor or the like irrespective of the running condition of the vehicle. Therefore, by controlling the electric motor based on the assist target current value including the inertia compensation value, a response delay due to inertia of the electric motor or the like is well compensated, and even under a situation where the vehicle is traveling on a large curve, A good steering feeling can be achieved even under a situation where the vehicle is running on a slalom road where small curves are continuous.

According to a second aspect of the present invention, the transfer function setting means may set an inertia compensation control transfer function based on a time differential value of the steering torque. According to a third aspect of the present invention, in the inertial compensation control transfer function,

[0009]

(Equation 3)

Wherein the transfer function setting means changes the time constant A2 in the function compensation control transfer function in accordance with the time differential value of the steering torque. The electric power steering control device according to claim 2, wherein (135) is included. According to the present invention, the inertia compensation control transfer function G (s) is set by changing the time constant A2 according to the time differential value of the steering torque.

The time constant changing means changes the time constant A2 to a smaller value as the time differential value of the steering torque increases.
It is preferable that the time constant A2 is changed to a larger value as the time differential value of the steering torque is smaller. In this case, as the time constant A2 is smaller, the inertia compensation control transfer function G
The amount of high-frequency components removed from the steering torque by the low-pass filter characteristic of (s) decreases, and as the time constant A2 increases, the high-frequency component is removed from the steering torque by the low-pass filter characteristic included in the inertial compensation control transfer function G (s). The amount of high frequency components increases.

Therefore, when the time differential value of the steering torque is small, the amount of high-frequency components removed from the steering torque when the steering torque is generated increases, so that the steering torque differential equivalent value that captures a gradual change in the steering torque is obtained. And an inertia compensation value that favorably compensates for a response delay due to inertia when the steering torque changes gently can be obtained based on the steering torque differential equivalent value. on the other hand,
When the time derivative of the steering torque is large, the amount of high-frequency components removed from the steering torque when the steering torque is generated decreases, so that a steering torque derivative equivalent value that captures a rapid change in the steering torque can be obtained. On the basis of the steering torque derivative equivalent value, an inertia compensation value that favorably compensates for a response delay due to inertia when the steering torque changes rapidly can be obtained.

According to a fourth aspect of the present invention, the inertial compensation control transfer function is:

[0014]

(Equation 4)

The transfer function setting means changes the gain A1 in the function compensation control transfer function in accordance with the time differential value of the steering torque. 4. The electric power steering control device according to claim 2, wherein the electric power steering control device includes: According to the invention,
By changing the gain A1 according to the time differential value of the steering torque, the inertia compensation control transfer function G (s) is set.

The gain changing means changes the gain A1 to a smaller value as the time differential value of the steering torque is smaller,
It is preferable that the gain A1 be changed to a larger value as the time differential value of the steering torque is larger. According to this configuration, when the time differential value of the steering torque is small, the gain A1 is set to a small value, and as a result, the generated steering torque differential equivalent value becomes a small value. If the inertia compensation current generating means sets the inertia compensation value to a smaller value as the steering torque derivative equivalent value becomes smaller, the inertia compensation value set based on the steering torque derivative equivalent value becomes a smaller value. In addition, there is no possibility that excessive steering assist is performed when the steering torque changes slowly. On the other hand, when the time differential value of the steering torque is large, the gain A1 is set to a large value. As a result, the generated steering torque differential equivalent value becomes a large value, and the inertia set based on this steering torque differential equivalent value is set. The compensation value becomes a large value. Therefore, there is no possibility that a response delay occurs when the steering torque changes abruptly.

According to a fifth aspect of the present invention, the transfer function setting means includes a comparison judging means (111) for judging the magnitude by comparing a time differential value of the steering torque with a predetermined reference value. When it is determined by the means that the time differential value of the steering torque is greater than the reference value, the inertia compensation control transfer function is set to a predetermined slalom travel transfer function G2 (s), and the comparison determination means determines When it is determined that the time differential value of the steering torque is equal to or smaller than the reference value, the inertia compensation control transfer function is set to a predetermined general travel transfer function G1 (s). An electric power steering control device according to claim 2.

According to the present invention, when the time differential value of the steering torque is larger than the reference value, the inertia compensation control transfer function is set to a predetermined slalom travel transfer function,
If the time derivative of the steering torque is less than or equal to the reference value,
The inertia compensation control transfer function is set to a predetermined general traveling transfer function. In other words, since the inertia compensation control transfer function is set according to the traveling situation, a good steering feeling can be achieved regardless of the traveling situation.

When the inertial compensation control transfer function has a low-pass filter characteristic (for example, of the type described in claim 3), the low-pass filter time constant (A2) included in the slalom travel transfer function is: It is preferably larger than the low-pass filter time constant (A2) included in the transfer function for general traveling. By doing so, for example, when the vehicle is traveling on a large curve, the amount of high-frequency components removed from the steering torque by the low-pass filter characteristic of the general travel transfer function increases, so that the steering torque gradually changes. Can be obtained, and based on the steering torque derivative equivalent value, an inertia compensation value that favorably compensates for a response delay due to inertia when the steering torque changes slowly can be obtained. . On the other hand, for example, when the vehicle is traveling on a slalom road, the amount of high-frequency components removed from the steering torque is reduced by the low-pass filter characteristic of the transfer function for the slalom traveling, so that a sharp change in the steering torque is captured. A steering torque differential equivalent value can be obtained, and based on the steering torque differential equivalent value, an inertia compensation value that favorably compensates for a response delay due to inertia when the steering torque changes rapidly can be obtained.

Therefore, a good steering feeling can be achieved regardless of the running condition.

[0021]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an electric configuration of an electric power steering apparatus according to one embodiment of the present invention. The steering torque applied to the steering wheel 1 is mechanically transmitted to a steering mechanism 3 via a steering shaft 2. The driving force generated from the electric motor 4 is transmitted to the steering mechanism 3 as a steering assist force via a driving force transmission mechanism such as a gear mechanism or a ball screw mechanism.

The steering shaft 2 is divided into an input shaft 2A connected to the steering wheel 1 and an output shaft 2B connected to the steering mechanism 3.
The input shaft 2A and the output shaft 2B are connected to each other by a torsion bar 5. Torsion bar 5
Generates twist in response to the steering torque applied to the steering wheel 1, and the direction and amount of the twist are detected by a torque sensor 6. The detection signal of the torque sensor 6 is input to a controller 10 including a microcomputer.

The controller 10 includes a vehicle speed sensor 7 for detecting a running speed (vehicle speed) V of the vehicle, and a motor current detecting circuit 8 for detecting a value of a motor current flowing through the electric motor 4 in addition to the detection signal of the torque sensor 6. Is input. A rotation angle sensor 9 for detecting the rotation angle of the electric motor 4 is provided in connection with the electric motor 4, and the motor rotation angle θ detected by the rotation angle sensor 9 is differentiated with respect to time by a differentiator 91. The obtained motor rotation angular velocity δθ is input to the controller 10. The controller 10 includes an input signal from the torque sensor 6, a vehicle speed V detected by the vehicle speed sensor 7, a motor current value detected by the motor current detection circuit 8, and a differentiator 91.
Based on the motor rotational angular velocity δθ generated by
The drive of the electric motor 4 is controlled so that a steering assist force corresponding to the operation of the steering wheel 1 is applied to the steering mechanism 3.

The controller 10 has, for example, a plurality of function processing units realized by executing an operation program stored in a storage medium (not shown) such as a ROM (not shown). These function processing units include a torque sensor 6
A phase compensator 11 for advancing the phase of the detection signal to stabilize the system, a basic assist current value corresponding to the steering torque T advanced in phase by the phase compensator 11 and the vehicle speed V detected by the vehicle speed sensor 7 A basic assist control unit 12 for generating I, an inertia compensation control unit 13 for generating an inertia compensation value ΔI1 for compensating a response delay due to inertia of the electric motor 4 and the like, a steering based on the vehicle speed V and the motor rotation angular speed δθ. Convergence control unit 1 that generates a convergence correction value ΔI2 for improving the convergence of wheel 1
4, a return control unit 1 that generates a return correction value ΔI3 for improving the steering performance when the steering wheel 1 returns based on the vehicle speed V and the motor rotational angular speed δθ.
5 are included.

The inertia compensation value ΔI1 generated by the inertia compensation control unit 13 is added to the basic assist current value I generated by the basic assist control unit 12 in the adding unit 16a. The convergence correction value ΔI2 generated by the convergence control unit 14 is:
The adder 16b adds the value to the sum output from the adder 16a. Further, the addition unit 16c adds the addition value output by the addition unit 16b and the return correction value ΔI3 generated by the return control unit 15, whereby the assist target current value I + ΔI1 + ΔI2 to be supplied to the electric motor 4 is obtained.
+ ΔI3 is obtained.

Assist target current value I + ΔI1 + ΔI2 +
ΔI3 is provided to the subtraction unit 17.
In the subtraction unit 17, the motor current value detected by the motor current detection circuit 8 and the assist target current value I + ΔI1 + Δ
The deviation from I2 + ΔI3 is determined. Then, the motor driver 18 that drives the electric motor 4 is controlled based on the obtained deviation. As a result, the electric motor 4 supplies the assist target current value I + ΔI1 + ΔI2 + ΔI3
, A proper steering assist force corresponding to the operation of the steering wheel 1 is generated from the electric motor 4.

FIG. 2 is a block diagram showing an electrical configuration of the inertial compensation control unit 13. The inertia compensation control unit 13 generates a steering torque differential equivalent value generation unit 131 that generates a steering torque differential equivalent value δT ′ corresponding to a time differential value of the steering torque T.
A control current value determining unit 132 for determining a control current value Δi corresponding to the steering torque differential equivalent value δT ′ generated by the steering torque differential equivalent value generating unit 131; and a vehicle speed corresponding to the vehicle speed V for the control current value Δi. A vehicle speed gain multiplication unit 133 that generates an inertia compensation value ΔI1 by multiplying the gain.

The steering torque differential equivalent value generating section 131 passes the steering torque T given from the phase compensating section 11 through an inertia compensation control transfer function G (s) having a low-pass filter characteristic, thereby obtaining a steering torque differential equivalent value δT 'Is generated. The inertial compensation control transfer function G (s) having the low-pass filter characteristic can be defined by the following equation (1), for example.

[0029]

(Equation 5)

The control current value determining section 132 sets the control current value Δi in accordance with the steering torque differential equivalent-control current value characteristic line shown in FIG. That is, the control current value determining unit 13
2, when the steering torque derivative equivalent value δT ′ generated by the steering torque derivative equivalent value generator 131 is in the range of 0 to 50 Nm / s,
The control current value Δi is set so as to increase from 0 to 1 A (ampere) in proportion to the steering torque differential equivalent value δT ′,
When the steering torque derivative equivalent value δT ′ is in the range of 50 to 100 Nm / s, the control current value Δi is set to 1A regardless of the steering torque derivative equivalent value δT ′.

The vehicle speed gain multiplying section 133 sets the vehicle speed gain according to the vehicle speed-vehicle speed gain characteristic line shown in FIG.
That is, the vehicle speed gain multiplication unit 133 determines that the vehicle speed V is 0 to 5
In the range of km / h, the vehicle speed gain is set so as to increase from 0 to 1 in proportion to the vehicle speed V, and the vehicle speed V becomes 40 to 100 km.
In the range of / h, the vehicle speed gain is set so as to decrease from 1 to 0.4 in proportion to the vehicle speed V. Also, the vehicle speed V is 5
In the range of 40 km / h, the vehicle speed gain is set to 1 regardless of the vehicle speed V. Then, the control current value Δi determined by the control current value determination unit 132 is multiplied by the vehicle speed gain set according to the vehicle speed V, and the result of the multiplication is output as an inertia compensation value ΔI1.

In this embodiment, the time constant A2 in the above equation (1) is automatically changed according to the steering condition of the vehicle. In order to achieve this function, the inertia compensation control unit 13 further includes a differentiator 134 for generating a steering torque differential value δT that is a time differential value of the steering torque T;
A time constant setting unit 135 for setting the time constant A2 based on the steering torque differential value δT generated by the differentiator 134. The gain A1 in the above equation (1) is a fixed value set based on characteristics of a vehicle on which the electric power steering device is mounted.

The time constant setting section 135 sets the time constant A2 according to, for example, a steering torque differential value-time constant characteristic line shown as an example in FIG. That is, the time constant setting unit 13
5 is 200 to 100 in proportion to the steering torque differential value δT when the steering torque differential value δT is in the range of 0 to 40 Nm / s.
The time constant A2 is set so as to decrease the steering torque differential value δT to 40 Nm / s or more.
Regardless of T, the time constant A2 is set to 100.

Thus, when the steering torque differential value δT is small, for example, when the steering wheel 1 is being steered slowly (for example, when traveling on a large curve), the time constant A2 becomes large. Is set. When the time constant A2 is large, when the steering torque T is passed through the inertial compensation control transfer function G (s) to generate the steering torque differential equivalent value δT ′, the amount of high frequency components removed from the steering torque T increases. . Therefore, the steering torque derivative equivalent value δ generated by the steering torque derivative equivalent value generator 131 is generated.
T 'is a value that captures a gradual change in the steering torque T,
As a result, in the inertia compensation control unit 13, the steering torque T
Generates an inertia compensation value ΔI1 capable of compensating for a response delay due to inertia in a case where changes gradually.

On the other hand, when the steering torque differential value δT is large,
That is, in a situation where the steering wheel 1 is quickly steered (for example, a situation where the vehicle is running on a slalom road where small curves are continuous), the time constant A2 is set to a small value. If the time constant A2 is small, the steering torque T
Is passed through the inertial compensation control transfer function G (s) to generate the steering torque differential equivalent value δT ′, the amount of high frequency components removed from the steering torque T decreases. Therefore, the steering torque derivative equivalent value δT ′ generated by the steering torque derivative equivalent value generator 131 is a value that captures a rapid change in the steering torque T. As a result, the inertia compensation controller 13 reduces the steering torque T suddenly. Is generated, an inertia compensation value ΔI1 capable of compensating for a response delay due to inertia in the case of changing to.

Therefore, by controlling the electric motor 4 based on the assist target current value I + ΔI1 + ΔI2 + ΔI3 including the inertia compensation value ΔI1, the response delay due to the inertia of the electric motor 4 and the like is well compensated, and the vehicle is traveling on a large curve. Good steering feeling can be achieved even under a situation or under a situation where the vehicle is running on a slalom road where small curves are continuous. Further, according to the configuration of this embodiment, the steering torque T is passed through the inertia compensation control transfer function G (s) to generate the steering torque differential equivalent value δT ′, and based on the steering torque differential equivalent value δT ′. Since the inertia compensation value ΔI1 is set, the sense of rigidity of the steering wheel 1 changes due to a change over time of the electric motor 4 or a change in tire pressure of the vehicle, and therefore, the magnitude of the steering torque T applied to the steering wheel 1 Is changed, this change can be compensated for by the inertia compensation value ΔI1. Therefore, there is no possibility that the steering feeling is deteriorated due to the aging.

FIG. 6 is a block diagram showing an electrical configuration of the inertial compensation control unit according to the second embodiment of the present invention.
The inertia compensation controller 100 according to the second embodiment can be used in place of the inertia compensation controller 13 (see FIG. 2) according to the first embodiment. In the following, description will be made focusing on differences from the inertial compensation control unit 13, and in FIG. 6, the same reference numerals will be given to the same parts as those shown in FIG.

Inertial compensation controller 13 according to the first embodiment
Has a time constant setting unit 135 for setting the time constant A2 in the above equation (1) based on the steering torque differential value δT, whereas the inertia compensation control unit 10 according to the second embodiment
0 has a gain setting unit 101 for setting the gain A1 in the above equation (1) based on the steering torque differential value δT. In the second embodiment, the time constant A2 is a fixed value set based on characteristics of a vehicle on which the electric power steering device is mounted.

The gain setting section 101 sets the gain A1 according to, for example, a steering torque differential value-gain characteristic line shown as an example in FIG. That is, the gain setting unit 10
1 is in the range of 2000 to 40 in proportion to the steering torque differential value δT when the steering torque differential value δT is in the range of 0 to 40 Nm / s.
The gain A1 is set so as to increase to 00, and if the steering torque differential value δT is 40 Nm / s or more, the gain A1 is set to 4000 regardless of the steering torque differential value δT.

Thus, when the steering torque differential value δT is small, the gain A1 is set to a small value. As a result, the steering torque differential equivalent value generation unit 131 converts the steering torque T to the inertia compensation control transfer function G (s). The steering torque differential equivalent value δT ′ generated by the passage is small. Therefore, the inertia compensation value ΔI1 set based on the steering torque differential equivalent value δT ′ is a small value, and there is no possibility that excessive steering assistance will be performed when the steering torque T changes slowly.

On the other hand, when the steering torque differential value δT is large, the gain A1 is set to a large value. As a result, the steering torque T is passed through the inertia compensation control transfer function G (s) in the steering torque differential equivalent value generation unit 131. As a result, the steering torque derivative equivalent value δT ′ becomes a large value, and accordingly, the inertia compensation value ΔI1 set based on the steering torque derivative equivalent value δT ′ becomes a large value. therefore,
When the steering torque T changes abruptly, there is no danger of insufficient steering assist force or delay in steering response.

Therefore, according to the configuration of the second embodiment, an effect that a good steering feeling can be obtained irrespective of the running condition can be achieved.
FIG. 8 is a block diagram showing an electrical configuration of the inertial compensation control unit according to the third embodiment of the present invention. The inertia compensation control unit 110 according to the third embodiment can be used in place of the inertia compensation control unit 13 (see FIG. 2) according to the above-described first embodiment. In FIG. 8, FIG.
Are denoted by the same reference numerals.

The inertia compensation control unit 110 includes a traveling state determination unit 111 for determining the traveling state of the vehicle, and a steering torque differential equivalent value δ according to the determination result of the traveling state determination unit 111
A steering torque differential equivalent value generation unit 112 that generates T ′;
A control current value determination unit 132 that determines a control current value Δi corresponding to the steering torque differential equivalent value δT ′ generated by the steering torque differential equivalent value generation unit 112, and a vehicle speed gain corresponding to the vehicle speed V as the control current value Δi. And a vehicle speed gain multiplying unit 133 that generates an inertia compensation value ΔI1 by multiplying by the multiplication.

The traveling situation determination unit 111 calculates, for example, a time differential value of the steering torque T, and if the calculated time differential value is equal to or less than a predetermined reference value (for example, 20 Nm / s), the vehicle turns into a large curve. Is determined to be running.
On the other hand, if the time differential value of the steering torque T is larger than the reference value, it is determined that the vehicle is traveling on a slalom road on which a small curve continues. Then, the determination result is given to the steering torque differential equivalent value generation unit 112.

When it is determined that the vehicle is traveling on a large curve, the steering torque differential equivalent value generation unit 112 adds the steering torque T to the general travel transfer function G of the following equation (2).
By multiplying by 1 (s), a steering torque differential equivalent value δT ′ is generated. On the other hand, when it is determined that the vehicle is traveling on the slalom road, the steering torque T is multiplied by a slalom traveling transfer function G2 (s) of the following equation (3) to obtain a steering torque differential equivalent value δT ′. Generate.

[0046]

(Equation 6)

Thus, when the vehicle is traveling on a large curve, the amount of high-frequency components removed from the steering torque T by the low-pass filter characteristic of the general traveling transfer function G1 (s) increases. Therefore, the steering torque derivative equivalent value δ generated by the steering torque derivative equivalent value generator 112
T 'is a value that captures a gradual change in the steering torque T,
As a result, the inertia compensation control unit 110 generates an inertia compensation value ΔI1 that can compensate for a response delay due to inertia when the steering torque T changes slowly. On the other hand, when the vehicle is traveling on a slalom road, the amount of high-frequency components removed from the steering torque T by the low-pass filter characteristic of the slalom traveling transfer function G2 (s) decreases. Therefore, the steering torque differential equivalent value δT ′ generated by the steering torque differential equivalent value generation unit 112 is a value that captures a rapid change in the steering torque T. As a result, the inertia compensation control unit 110 reduces the steering torque T rapidly. Inertia compensation value Δ that can compensate for the response delay due to inertia when
I1 is generated.

Therefore, as in the case of the above-described first and second embodiments, a good steering feeling can be achieved irrespective of running conditions. As described above, the three embodiments of the present invention have been described.
Other embodiments are possible. For example, in the third embodiment described above, it is determined whether the vehicle is traveling on a large curve or a slalom road based on the time differential value of the steering torque T. However, the frequency at which the steering direction of the steering wheel 1 is switched is detected based on the steering torque T, and if this frequency is equal to or less than a predetermined value, it is determined that the vehicle is traveling on a large curve, If the value is larger than the predetermined value, it may be determined that the vehicle is traveling on a slalom road.

The steering torque derivative equivalent value-control current value characteristic line in FIG. 3 and the vehicle speed-vehicle speed gain characteristic line in FIG.
Both are examples, and may be appropriately changed according to the characteristics of the vehicle and the like. In addition, various design changes can be made within the scope of the matters described in the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electric power steering device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an electrical configuration of an inertial compensation control unit.

FIG. 3 is a diagram illustrating an example of a steering torque differential equivalent value-control current value characteristic line.

FIG. 4 is a diagram illustrating an example of a vehicle speed-vehicle speed gain characteristic line.

FIG. 5 is a diagram showing an example of a steering torque differential value-time constant characteristic line.

FIG. 6 is a block diagram illustrating an electrical configuration of an inertial compensation control unit according to a second embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of a steering torque differential value-gain characteristic line.

FIG. 8 is a block diagram illustrating an electrical configuration of an inertial compensation control unit according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 steering wheel 4 electric motor 10 controller 12 basic assist control unit 13 inertia compensation control unit 131 steering torque differential equivalent value generation unit 132 control current value determination unit 133 vehicle speed gain multiplication unit 134 differentiator 135 time constant setting unit 16a addition unit 16b addition Unit 16c Addition unit 17 Subtraction unit 18 Motor driver 100 Inertial compensation control unit 101 Gain setting unit 110 Inertial compensation control unit 111 Running situation determination unit 112 Steering torque differential equivalent generation unit

Claims (5)

[Claims] 1. A control device for an electric power steering device for generating a steering assist force by an electric motor driven based on a steering torque applied to an operation member, wherein a basic assist current value according to the steering torque is provided. , A transfer function setting means for setting an inertia compensation control transfer function according to the running condition of the vehicle, and passing the steering torque through the inertia compensation control transfer function set by the transfer function setting means. A steering torque differential equivalent value generating means for generating a steering torque differential equivalent value by means of: A basic assist current value generated by the basic assist current generation means, and an inertia compensation value generated by the inertia compensation current generation means And a motor driving means for driving an electric motor based on the assist target current value generated by the target current value generating means. Electric power steering control device. 2. The electric power steering control device according to claim 1, wherein said transfer function setting means sets an inertia compensation control transfer function based on a time differential value of a steering torque. 3. The inertia compensation control transfer function is given by: Wherein the transfer function setting means includes time constant changing means for changing the time constant A2 in the function compensation control transfer function according to the time differential value of the steering torque. The electric power steering control device according to claim 2, wherein: 4. The transfer function of the inertia compensation control is: Wherein the transfer function setting means includes gain changing means for changing the gain A1 in the function compensation control transfer function in accordance with the time differential value of the steering torque. The electric power steering control device according to claim 2 or 3, wherein: 5. The transfer function setting means includes a comparison judging means for judging the magnitude by comparing a time differential value of the steering torque with a predetermined reference value. If it is determined that the transfer function is larger than the reference value, the inertia compensation control transfer function is set to a predetermined slalom travel transfer function, and the time differential value of the steering torque is equal to or less than the reference value by the comparison and determination means. 3. The electric power steering control device according to claim 2, wherein when the determination is made, the inertia compensation control transfer function is set to a predetermined general travel transfer function.