JP2002029444A - Electric power steering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power steering preventing a driver from feeling a sense of incongruity when correcting an assist characteristic. SOLUTION: In this electric power steering, the target value of a motor current of a steering force assist motor is determined on the basis of steering torque detected by a torque sensor, and vehicle speed detected by a vehicle speed sensor, and the motor is rotationally driven so that the motor current becomes the target value. Steering speed is computed from a steering angle detected by a steering angle sensor, and a coefficient for correcting the target value of the motor current is obtained on the basis of the computed steering speed and the steering torque (S22). The target value of the motor current is corrected with the obtained coefficient to assist steering force. The electric power steering is provided with a means for determining whether the steering angle detected by the steering angle sensor is within a specified range including a steering angle midpoint (S24), and a means for correcting the target value of the motor current (S26) with the obtained coefficient (S22) only when the determining means determines that the steering angle is within the specified range (S24).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention determines a target value of a motor current of a steering force assisting motor based on a steering torque detected by a torque sensor and a vehicle speed detected by a vehicle speed sensor. The motor is rotationally driven to a value, a steering speed is calculated from the steering angle detected by the steering angle sensor, a target value of the motor current is corrected based on the calculated steering speed and steering torque, and steering force assistance is performed. The present invention relates to an improvement in an electric power steering device.

[0002]

2. Description of the Related Art A conventional electric power steering apparatus is
Since the assist table, which is the relationship between the steering torque and the motor current target value of the steering force assist motor, is determined on the assumption of a dry asphalt road surface, when the friction coefficient of the road surface is small (such as on a snowy or wet road surface) In the case of (1), it is expected that the assist will be excessive, and conversely, if the coefficient of friction of the road surface is large (such as a dry concrete road surface), the assist will be insufficient. Therefore, the driver may feel a sense of strangeness in the steering feeling.

In Japanese Patent Application No. 12-103924, the present applicant accumulates a steering speed and a steering torque for a predetermined period of time, respectively, and performs a steering operation based on the integrated steering speed, the integrated steering torque, and the vehicle speed. An electric power steering device that corrects the target value (assist characteristic) of the motor current of the power assisting motor and rotationally drives the steering force assisting motor to assist the steering force so that the motor current becomes the corrected target value. Has been proposed.

[0004]

However, when the driver corrects the assist characteristics during steering as described above, there is a problem that the driver senses a sudden change in the steering force and feels uncomfortable. Also, for example, as in the case where the road enters a dry area from a rainy area, the assist characteristic is changed from the assist characteristic in which the assist force is minimized to the uncorrected assist characteristic, and the assist force is rapidly increased. In the case where it is necessary to perform the assisting, there is a problem that the steering force becomes insufficient due to an insufficient assisting force, and it may not be possible to determine whether correction of the assist characteristic is necessary.

The present invention has been made in view of the above-described circumstances, and the first and second inventions provide an electric power steering apparatus in which a driver does not feel uncomfortable when correcting the assist characteristics. The purpose is to: Third
The fourth object of the present invention is to provide an electric power steering apparatus in which the assist force is not insufficient and the steering cannot be disabled even when the assist force needs to be rapidly increased.

[0006]

An electric power steering apparatus according to a first aspect of the present invention provides a target value of a motor current of a steering force assisting motor based on a steering torque detected by a torque sensor and a vehicle speed detected by a vehicle speed sensor. Is determined, the motor is rotationally driven so that the motor current becomes a target value, a steering speed is calculated from a steering angle detected by a steering angle sensor, and the target value is calculated based on the calculated steering speed and the steering torque. In an electric power steering device that obtains a coefficient for correction, corrects the target value with the obtained coefficient, and assists steering force, it is determined whether the steering angle is within a predetermined range including a steering angle midpoint. It is characterized by comprising means for determining, and means for correcting the target value by the obtained coefficient when the means determines that it is within a predetermined range.

In this electric power steering apparatus, a target value of the motor current of the steering force assisting motor is determined based on the steering torque detected by the torque sensor and the vehicle speed detected by the vehicle speed sensor. The motor is rotationally driven so that the steering angle is calculated from the steering angle detected by the steering angle sensor, and a coefficient for correcting the target value of the motor current is calculated based on the calculated steering speed and steering torque. The target value of the motor current is corrected by the coefficient to assist the steering force. The determining means determines whether or not the steering angle is within a predetermined range including the steering angle midpoint, and the correcting means uses the coefficient obtained when the determining means determines that the steering angle is within the predetermined range. Correct the motor current target value. As a result, the assist characteristic is corrected only when the steering angle is near the midpoint of the steering angle based on the coefficient determined during steering, so that when correcting the assist characteristic, the electric power steering system does not cause the driver to feel uncomfortable. The device can be realized.

An electric power steering apparatus according to a second aspect of the present invention determines a target value of a motor current of a steering force assisting motor based on a steering torque detected by a torque sensor and a vehicle speed detected by a vehicle speed sensor. The motor is rotationally driven so that the current becomes a target value, a steering speed is calculated from a steering angle detected by a steering angle sensor, the target value is corrected based on the calculated steering speed and the steering torque, and a steering force is corrected. In the electric power steering apparatus for assisting, the target value is corrected stepwise.

In this electric power steering apparatus, a target value of the motor current of the steering force assisting motor is determined based on the steering torque detected by the torque sensor and the vehicle speed detected by the vehicle speed sensor. , The steering speed is calculated from the steering angle detected by the steering angle sensor, the target value of the motor current is corrected based on the calculated steering speed and steering torque, and the steering force is assisted. The correction of the target value of the motor current is performed stepwise. Thus, it is possible to realize an electric power steering device in which the driver does not feel uncomfortable when correcting the assist characteristics.

An electric power steering apparatus according to a third aspect of the present invention determines a target value of a motor current of a steering force assisting motor based on a steering torque detected by a torque sensor and a vehicle speed detected by a vehicle speed sensor. The motor is rotationally driven so that the current becomes a target value, a steering speed is calculated from a steering angle detected by a steering angle sensor, the target value is corrected based on the calculated steering speed and the steering torque, and a steering force is corrected. In an electric power steering apparatus for assisting, a steering speed determining unit for determining whether the steering speed is within a predetermined range including 0, a unit for calculating a change in the steering torque, and a change calculated by the unit. Determining means for determining whether or not the value exceeds a predetermined value, wherein the steering speed determining means determines that the steering speed is within a predetermined range, and the determining means determines that the value exceeds a predetermined value. Prohibits the correction of the target value, characterized in that it is returned to the uncorrected target value are none to perform the steering force assist.

In this electric power steering apparatus, a target value of the motor current of the steering force assisting motor is determined based on the steering torque detected by the torque sensor and the vehicle speed detected by the vehicle speed sensor. , The steering speed is calculated from the steering angle detected by the steering angle sensor, the target value of the motor current is corrected based on the calculated steering speed and steering torque, and the steering force is assisted. The steering speed determining means determines whether or not the steering speed is within a predetermined range including 0, the calculating means calculates a change in the steering torque, and the determining means determines whether or not the calculated change exceeds a predetermined value. Is determined. Then, when the steering speed determining means determines that the current value is within the predetermined range, and when the determining means determines that the predetermined value is exceeded, the correction of the target value of the motor current is prohibited, and the motor current is returned to the uncorrected target value. Perform steering force assistance.

Thus, an electric power steering apparatus can be realized in which even when the assist force needs to be rapidly increased, the assist force is not insufficient and steering cannot be disabled.

An electric power steering apparatus according to a fourth aspect of the present invention is characterized in that the return to the uncorrected target value is performed in a stepwise manner.

In this electric power steering apparatus, the return to the uncorrected target value is performed in a stepwise manner. Therefore, even when the assist force needs to be sharply increased, the assist force is insufficient. It is possible to realize an electric power steering device that does not become excessively large and cannot be steered, and can smoothly perform steering assist regardless of the steering force of the driver.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing the embodiments. FIG. 1 is a block diagram showing a main configuration of an electric power steering apparatus according to an embodiment of the present invention. In this electric power steering apparatus, a torque detected by a torque sensor 10 for detecting a torque applied to a steering shaft (not shown) is supplied to a microcomputer 12 via an interface circuit 11, and a vehicle speed sensor 20 for detecting a vehicle speed. The detection signal of
It is provided to the microcomputer 12 via the interface circuit 21. A steering angle signal of a steering angle sensor 22 for detecting a steering angle of a steering shaft is transmitted to an interface circuit 23.
To the microcomputer 12 via

A relay control signal output from the microcomputer 12 is supplied to a relay drive circuit 15, and the relay drive circuit 15 turns on or off the fail-safe relay 15a according to the relay control signal. The clutch control signal output from the microcomputer 12 is supplied to a clutch drive circuit 16, and the clutch drive circuit 16 turns on or off the clutch 19 according to the clutch control signal. The drive power for the clutch 19 is supplied from a terminal on the motor drive circuit 13 side of the fail-safe relay 15a.

The microcomputer 12 refers to a vehicle characteristic table 18c, an assist command correction table 18b, and a torque / current table 18a in the memory 18 based on the detected torque, vehicle speed, steering angle, and motor current, which will be described later. A control signal is created, and the created motor control signal is provided to the motor drive circuit 13. The motor drive circuit 13 rotationally drives a brushless motor 24, which is a steering assist motor, based on the supplied motor control signal. When the brushless motor 24 rotates, a rotor position detector 1 such as a resolver or a rotary encoder is used.
4 detects the rotor position, and the motor drive circuit 13
Based on the detected rotor position signal, the rotation of the brushless motor 24 is controlled by PWM (Pulse Width Modulation) control. The motor current of the brushless motor 24 flowing through the motor drive circuit 13 is detected by the motor current detection circuit 17 and supplied to the microcomputer 12.

Hereinafter, the operation of the electric power steering apparatus having such a configuration will be described with reference to the flowchart of FIG. Microcomputer 12
Reads the steering angle signal detected by the steering angle sensor 22 (S
2) The steering speed N is calculated by differentiating the read steering angle signal (S4). Next, the microcomputer 12 reads the torque detection signal detected by the torque sensor 10 and sets it as the steering torque T (S6), and reads the vehicle speed V (vehicle speed signal) detected by the vehicle speed sensor 20 (S8).

Next, the microcomputer 12 performs an assist correction based on the calculated (S4) steering speed N, the read (S6) steering torque T, and the read (S8) vehicle speed V (S10). In the assist correction, (post-correction assist table) = (pre-correction assist table) × (k / 1)
00) is calculated.

Next, the microcomputer 12 reads the read vehicle speed V (S8) and the read steering torque T (S6).
Then, the motor current is obtained by referring to the torque / current table 18a (assistance table before correction), and the target motor current is calculated by multiplying the obtained motor current by the correction coefficient k obtained in the assist correction (S10) (S11). ).

Next, the microcomputer 12 reads the motor current signal detected by the motor current detection circuit 17 (S12) and calculates the read motor current signal (S12).
11) Compare the target motor current with the brushless motor 2
Then, the output level and the rotation direction are determined so that the target motor current flows through S4 (S14), and an instruction signal of the output level and the rotation direction is given to the motor drive circuit 13 (S16), and the process returns. The motor drive circuit 13 drives the brushless motor 24 to rotate based on the given output level and rotation direction instruction signal.

FIG. 3 is a flowchart showing a detailed operation of the assist correction (S10). In the assist correction (S10), the microcomputer 12 first determines whether the calculated (S4) steering speed (motor rotation speed) is within a predetermined range including 0, and whether the steering speed is approximately 0 (S4).
20). If the steering speed is not substantially 0, a step of calculating a correction coefficient target value kobj for assist correction (S2).
Perform 2).

After calculating the correction coefficient target value kobj (S22), the microcomputer 12 reads the correction coefficient target value kobj (S2).
From the steering angle signal, it is determined whether or not the steering angle is within a predetermined range including the steering angle midpoint, and it is determined whether or not the steering wheel position is at a substantially neutral position (S24). If the steering wheel position is substantially neutral, the correction coefficient target value kobj is set as the correction coefficient k (S
26), execute assist correction and return. The microcomputer 12 determines whether or not the steering wheel position is substantially neutral (S24). If the steering wheel position is not substantially neutral, the microcomputer 12 calculates (S22) the correction coefficient target value kobj.
Then, the magnitude of the current correction coefficient k is determined (S34).

When the calculated correction coefficient target value kobj is larger than the current correction coefficient k (S34), the microcomputer 12 adds a positive constant b to the correction coefficient k (S36) and returns. As a result, the microcomputer 12 adds a positive constant b to the correction coefficient k every time sampling is performed until the correction coefficient k reaches the correction coefficient target value kobj, as shown in FIG.
The assist correction can be executed step by step.

When the calculated (S22) correction coefficient target value kobj is equal to or smaller than the current correction coefficient k (S34), the microcomputer 12 determines whether or not the correction coefficient target value kobj is less than the current correction coefficient k. (S38) If it is less than the correction coefficient k, a positive constant b is subtracted from the correction coefficient k (S40) and the process returns. If the correction coefficient target value kobj is substantially equal to the current correction coefficient k (S38), the process returns. Thereby, the microcomputer 12 sets the correction coefficient k to the correction coefficient target value k, as shown in FIG.
Until obj, a positive constant b is subtracted from the correction coefficient k every time sampling is performed, so that the assist correction can be executed stepwise.

On the other hand, the microcomputer 12 corrects the correction coefficient target value kobj at that time if the steering wheel position becomes substantially neutral before the correction coefficient k reaches the correction coefficient target value kobj (S24). (S2
6) Execute the assist correction. As described above, the microcomputer 12 temporarily performs the assist correction based on the calculated (S22) correction coefficient target value kobj only when the steering wheel position is substantially at the neutral position (S24), and the steering wheel position is not substantially at the neutral position. At (S24), the assist correction can be executed step by step.

When the calculated (S4) steering speed (motor rotation speed) is not in a predetermined range including 0 and the steering speed is not substantially 0 (S20), the microcomputer 12 reads the read (S6) torque detection signal and Then, a torque change amount is calculated from the torque detection signal read at the previous sampling (S6) (S28), and it is determined whether the calculated torque change amount is larger than a predetermined value (S30). When the calculated amount of change in torque is smaller than the predetermined value, a step (S22) of calculating a correction coefficient target value kobj for performing the assist correction is executed, and normal assist correction is performed.

When the calculated torque variation is larger than the predetermined value (S30), the microcomputer 12 sets the correction coefficient target value kobj to 100 without calculating the correction coefficient target value kobj for assist correction (S3).
2) Stop assist correction. Next, the microcomputer 12 determines the magnitude of the correction coefficient target value kobj set to 100 and the current correction coefficient k (S34).

When the correction coefficient target value kobj of 100 is larger than the current correction coefficient k (S34), the microcomputer 12 adds a positive constant b to the correction coefficient k (S36) and returns. Thus, the microcomputer 12 adds a positive constant b to the correction coefficient k every time sampling is performed until the correction coefficient k reaches the correction coefficient target value kobj (= 100), as shown in FIG. In other words, the assist correction can be executed step by step.

When the correction coefficient target value kobj, which is 100, is equal to or smaller than the current correction coefficient k (S34), the microcomputer 12 determines whether the correction coefficient target value kobj is less than the current correction coefficient k (S38). If it is less than the correction coefficient k, a positive constant b is subtracted from the correction coefficient k (S40).
To return. If the correction coefficient target value kobj is substantially equal to the current correction coefficient k (S38), the process returns. Thereby, the microcomputer 12 sets the correction coefficient k to the correction coefficient target value kobj (= 1, as shown in FIG.
00), a positive constant b is subtracted from the correction coefficient k every time sampling is performed, so that the assist correction can be executed in a stepwise manner.

On the other hand, if the microcomputer 12 determines that the steering wheel position becomes substantially neutral before the correction coefficient k reaches the correction coefficient target value kobj (= 100) (S
24) At that time, the correction coefficient target value kobj is changed to the correction coefficient k
(S26), the assist correction is executed. As described above, even when the amount of change in torque becomes larger than the predetermined value (S30) and the assist force needs to be rapidly increased, the microcomputer 12 does not become too short of the assist force and cannot disable steering. In addition, the steering assist can be smoothly performed in a stepwise manner regardless of the driver's steering force.

FIG. 5 is a flowchart showing the detailed operation of the step (S22) of calculating the correction coefficient target value kobj for assist correction. Microcomputer 12
In the correction coefficient target value calculation (S22), the read (S
8) It is determined from the vehicle speed signal whether or not the vehicle speed V is greater than a positive constant a, and whether or not the vehicle is running is determined (S).
50).

If the vehicle is running (S50), the microcomputer 12 performs the steering operation (S2) currently being performed.
Is determined from the neutral position of the steering angle at which the vehicle should go straight (S52). If the steering is from the neutral position of the steering angle, the steering is performed in the same direction as the previous sampling. Is determined (S54). If the steering is in the same direction as the previous sampling (S54), the microcomputer 12 determines whether or not a waiting time (for example, 0.1 second) has elapsed since the steering was started (S56). .

If the waiting time has elapsed (S56), the microcomputer 12 integrates the read steering torque T (S6), and integrates the calculated steering speed N (S4) (S58). Next, after the elapse of the waiting time (S56), the microcomputer 12 determines whether or not a predetermined integration time for integrating the steering torque T and the steering speed N has elapsed (S60).

If the predetermined integration time has elapsed (S60), the microcomputer 12 calculates the integrated steering speed Σ.
It is determined whether N is within the applicable range (b <ｂN <c: b and c are positive constants) (S62). This is because in the vehicle characteristic table 18c (storage means) as shown in FIG.
This is because the integrated steering speed value ΣN out of the applicable range (for example, when abnormal steering such as a sharp steering wheel is performed) is not used for assist correction. Vehicle characteristic table 1
8c is a vehicle characteristic that varies depending on the vehicle weight, tires, and the like ^. The relationship between the steering speed integrated value ΣN and the steering torque integrated value ΣT ^* to be integrated according to the vehicle speed on a reference, for example, a dry asphalt road surface is represented by the vehicle speed. (For each vehicle speed).

If the integrated steering speed ΣN is within the applicable range, the microcomputer 12 displays the integrated steering speed ΣN and the integrated steering torque ΣT ^* corresponding to the read (S8) vehicle speed V in FIG. Vehicle characteristic table 1 as shown
8c is read (S64). Microcomputer 12
Is calculated from the read (S64) integrated steering torque value ΔT ^* and the integrated (S58) steering torque ΔT, by the operation ΔT ^* −.
ΣT is executed, and when the value is approximately 0 (S66),
For example, in FIG. 7, the value of the correction coefficient k is kept unchanged, and the integrated steering speed 操 N and the integrated steering torque ΣT
For example, the parameters for calculating the correction coefficient target value (S22) are reset (S68). This corresponds to, for example, FIG. 7 as described above, and indicates that it is appropriate assistance. Therefore, the correction coefficient k is kept unchanged, and the assist torque is reduced as shown in the assist command correction table 18b in FIG. Do not correct.

The microcomputer 12 calculates {T ^{* −} }
If T <0 (S66), the current correction coefficient k is compared with the maximum correction coefficient value kmax (k> kmax-d,
d: positive constant) (S70). As a result of the comparison, if there is room to increase the correction coefficient k by a constant d (S70), the microcomputer 12 sets k + d as a new correction coefficient target value kobj (S72), and there is no room to increase the correction coefficient k by a constant d. (S70), the maximum value of the correction coefficient km
ax as a new correction coefficient target value kobj (S74),
The parameters for calculating the correction coefficient target value (S22), such as the integrated steering speed ΣN and the integrated steering torque ΣT, are reset (S68). This corresponds to, for example, FIG. 7 and indicates that the assist is insufficient, so that the correction coefficient k is increased and the assist torque is increased as shown in the assist command correction table 18b in FIG.

The microcomputer 12 calculates {T ^{* −} }
When T> 0 (S66), a comparison between the current correction coefficient k and the minimum correction coefficient kmin (k> kmin + d,
d: positive constant) (S76). As a result of the comparison, if there is room to reduce the correction coefficient k by a constant d (S76), the microcomputer 12 sets k-d as a new correction coefficient target value kobj (S78), and allows the microcomputer 12 to reduce the correction coefficient k by a constant d. If there is no (S76), the minimum value of the correction coefficient km
in as a new correction coefficient target value kobj (S80),
The parameters for calculating the correction coefficient target value (S22), such as the integrated steering speed ΣN and the integrated steering torque ΣT, are reset (S68). This corresponds to, for example, FIG. 7 and indicates that the assist is excessive, so that the correction coefficient k is reduced and the assist torque is reduced as shown in the assist command correction table 18b of FIG.

The microcomputer 12 determines whether or not the vehicle is running (S50), and if the vehicle is not running (S50), calculates the correction coefficient target value during execution (S2).
2) is interrupted, and parameters for calculating the correction coefficient target value (S22), such as the integrated steering speed value ΣN and the integrated steering torque value ΣT, are reset (S68). The microcomputer 12 determines whether the steering currently being performed (S2) is a steering from a neutral position at which the vehicle should go straight ahead (S52), and if the steering is not from a neutral position. Since the correction coefficient target value is not calculated (S22), the process returns.

The microcomputer 12 determines whether or not the steering is in the same direction as the previous sampling (S54). If the steering is not in the same direction as the previous sampling, the microcomputer 12 waits as shown in FIG. This is the case where the steering direction has changed before the time and the integration time have elapsed, and the correction coefficient target value calculation (S22) being executed is interrupted, and the correction coefficient such as the steering speed integrated value ΣN and the steering torque integrated value ΣT is corrected. The parameters for calculating the target value (S22) are reset (S68).

The microcomputer 12 determines whether or not a waiting time has elapsed since the start of the steering (S56). If the waiting time has not elapsed, the microcomputer 12 continues to calculate the correction coefficient target value (S22). In order to do so, return as it is. The microcomputer 12 determines whether or not a predetermined integration time for integrating the steering torque T and the steering speed N has elapsed (S60). If the integration time has not elapsed, the microcomputer 12 calculates a correction coefficient target value (S60). Return to step S22) to continue.

The microcomputer 12 determines whether the integrated steering speed ΔN is within the applicable range (S6).
2) If it is not within the applicable range, the correction coefficient target values such as the integrated steering speed ΣN and the integrated steering torque ΣT are calculated (S2
The parameters for 2) are reset (S68). This is, for example, the case where the integrated steering speed ΣN is out of the applicable range as shown in FIG. 7, and does not correct the assist torque as shown in the assist command correction table 18b in FIG.

[0043]

According to the electric power steering apparatus of the first invention, the assist characteristic is corrected when the steering angle is near the steering angle midpoint by the coefficient obtained during steering.
When correcting the assist characteristics, it is possible to realize an electric power steering device in which the driver does not feel uncomfortable.

According to the electric power steering apparatus according to the second aspect of the present invention, it is possible to realize an electric power steering apparatus in which the driver does not feel uncomfortable when correcting the assist characteristics.

According to the electric power steering apparatus according to the third aspect of the present invention, even when it is necessary to rapidly increase the assist force, the electric power steering apparatus does not become too insufficient in the assist force to make steering impossible. Can be realized.

According to the electric power steering apparatus of the fourth aspect, even when the assist force needs to be rapidly increased, the steering force is not insufficient and the steering cannot be disabled. An electric power steering apparatus capable of smoothly performing steering assist regardless of the steering force can be realized.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing an operation of the electric power steering device shown in FIG.

FIG. 3 is a flowchart showing an operation of the electric power steering device shown in FIG.

FIG. 4 is an explanatory diagram for explaining an operation of the electric power steering device shown in FIG. 1;

FIG. 5 is a flowchart showing an operation of the electric power steering device shown in FIG.

FIG. 6 is an explanatory diagram for explaining an operation of the electric power steering device shown in FIG. 1;

FIG. 7 is an explanatory diagram for explaining a vehicle characteristic table.

FIG. 8 is an explanatory diagram for explaining an assist command correction table.

[Explanation of symbols]

 Reference Signs List 10 Torque sensor 12 Microcomputer 13 Motor drive circuit 17 Motor current detection circuit 18a Torque / current table 18b Assist command correction table 18c Vehicle characteristic table (storage means) 20 Vehicle speed sensor 22 Steering angle sensor 24 Brushless motor

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Keisuke Izumiya 3-5-8 Minamisenba, Chuo-ku, Osaka City, Osaka Prefecture F-term (reference) 3D032 CC16 DA03 DA15 DA23 DA63 DA64 DA97 DC08 DD01 EA01 EC23 EC27 GG01 3D033 CA05 CA13 CA16 CA17 CA20 CA23

Claims (4)

[Claims] 1. A steering torque detected by a torque sensor,
A target value of the motor current of the steering force assisting motor is determined based on the vehicle speed detected by the vehicle speed sensor, and the motor is rotationally driven so that the motor current becomes the target value, and the steering angle detected by the steering angle sensor is determined. An electric power steering apparatus that calculates a steering speed from the calculated steering speed, calculates a coefficient for correcting the target value based on the calculated steering speed and the steering torque, corrects the target value with the obtained coefficient, and assists the steering force. A means for determining whether or not the steering angle is within a predetermined range including a steering angle midpoint; and correcting the target value by the obtained coefficient when the means determines that the steering angle is within a predetermined range. And an electric power steering device. 2. A steering torque detected by a torque sensor,
A target value of the motor current of the steering force assisting motor is determined based on the vehicle speed detected by the vehicle speed sensor, and the motor is rotationally driven so that the motor current becomes the target value, and the steering angle detected by the steering angle sensor is determined. Calculating the steering speed from, and correcting the target value based on the calculated steering speed and the steering torque,
An electric power steering device for assisting a steering force, wherein the target value is corrected stepwise. 3. A steering torque detected by a torque sensor,
A target value of the motor current of the steering force assisting motor is determined based on the vehicle speed detected by the vehicle speed sensor, and the motor is rotationally driven so that the motor current becomes the target value, and the steering angle detected by the steering angle sensor is determined. Calculating the steering speed from, and correcting the target value based on the calculated steering speed and the steering torque,
In an electric power steering apparatus for assisting a steering force, a steering speed determining unit that determines whether the steering speed is within a predetermined range including 0, a unit that calculates a change in the steering torque, and a unit that calculates the steering torque. Determining means for determining whether or not the changed change has exceeded a predetermined value. When the steering speed determining means determines that the change is within a predetermined range, and the determining means determines that the change has exceeded a predetermined value, the target An electric power steering apparatus characterized in that correction of a value is prohibited, and the steering is assisted by returning to a target value that has not been corrected. 4. The electric power steering apparatus according to claim 3, wherein the return to the uncorrected target value is performed stepwise.