JP3525541B2 - Electric power steering device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric power steering device for assisting a steering force of a vehicle by a driving force of an electric motor.

[0002]

2. Description of the Related Art Conventionally, electric power steering systems are
A motor is coupled to the steering device via a speed reducer having a large reduction ratio. Further, since load torque such as friction torque exists in the motor, the load torque amplified by the reduction ratio of the speed reducer becomes drag torque to the steering device.

On the other hand, a vehicle not provided with a power steering device has a structure in which when the steering wheel is released after turning, the steering wheel is automatically restored to the neutral position by the self-aligning torque generated in the tire. However, in the case of a vehicle provided with the electric power steering device, the steering torque cannot be restored to the neutral position because the drag torque is larger than the self-aligning torque.

Therefore, as disclosed in Japanese Patent Publication No. 6-29032, there has been proposed a steering angle sensor which controls the steering wheel to be restored to the neutral position based on the detected steering angle.

[0005]

However, the one using the steering angle sensor has a problem that the structure of the steering angle sensor is complicated. Further, since the steering is operated by multiple rotations and it is difficult to detect the absolute steering angle, a steering angle sensor that measures a rotation pulse to detect the steering angle is generally used. However, this method has a problem that it is difficult to obtain the neutral steering angle position because only the relative position can be detected.

Therefore, an object of the present invention is to perform restoration control to a neutral position without using a steering angle sensor.

[0007]

In order to achieve the above-mentioned object, the present invention provides a motor (13) for generating an assist torque for steering a vehicle steering wheel (12) according to the first aspect of the invention. An electric power steering system comprising: a steering torque detecting means (1) for detecting a steering torque of the steering and outputting a steering torque signal; and controlling an assist torque by the motor based on the outputted steering torque signal. The apparatus includes restoration compensating means (3, 20, 40) for restoring the steering to a neutral position based on the wheel speed of the left and right steered wheels of the vehicle, and the restoration compensating means restores based on the wheel speed.
Outputs a restoration compensation signal to generate compensation torque.
Signal generating means (20, 40) and the output restoration
The steering torque signal was restored and compensated by the compensation signal.
A conversion means (3) for converting into a signal,
The means (40) adjusts the wheel speed of the left and right steered wheels of the vehicle.
From the control device (30) for performing other control of the vehicle based on the above
A signal for determining the wheel speed ratio is input via the signal line.
The input signal is applied to the restoration compensation signal.
It is characterized by being output .

[0008]

According to the second aspect of the invention, a motor (13) for generating an assist torque for steering the steering wheel (12) of the vehicle, and a steering wheel for detecting the steering torque of the steering wheel and outputting a steering torque signal. The torque detection means (1) outputs a restoration compensation signal for generating a restoration compensation torque based on the wheel speeds of the left and right steered wheels of the vehicle, and a gain for vehicle speed response based on the traveling speed of the vehicle. Signal generation means (20, 40) for outputting a vehicle speed sensitive gain signal, and conversion means (3) for converting the output steering torque signal by the output restoration compensating signal into a restoration-compensated signal. , Determines the rotational drive direction of the motor based on the signal subjected to the restoration compensation, and outputs an assist torque signal for driving the motor. An assist torque calculation means (4),
Gain changing means (5) for changing the gain of the output assist torque signal according to the vehicle speed sensitive gain signal, the magnitude of the assist torque signal with the changed gain, and the determined rotational driving direction of the motor. Based on the motor drive means (6 ~
9) and the signal generating means (40) is the vehicle.
Other control of the vehicle is performed based on the wheel speed of the left and right steered wheels.
For determining the wheel speed ratio from the control device (30)
The signal is input through the signal line, and this input signal
The electric power system that outputs the restoration compensation signal
It is an alling device .

In the invention according to claim 3 , the invention according to claim 1 or
In the electric power steering apparatus according to the second aspect, the steering torque signal is a DC signal that proportionally changes with respect to the steering torque, and the conversion unit DC-shifts the steering torque signal by the restoration compensation signal. It is characterized by being According to a fourth aspect of the present invention, in the electric power steering apparatus according to the third aspect , the signal generating means outputs a pulse signal having a duty ratio indicating the restoration compensation torque, and the converting means has the It is characterized in that a pulse signal is converted into a DC signal and the steering torque signal is DC-shifted by the DC signal.

According to a fifth aspect of the present invention, the first to third aspects are provided.
In the electric power steering device according to any one of 4 above, the signal generating means (20) outputs the left / right wheel speed signals from a wheel speed signal from a wheel speed detecting means for detecting wheel speeds of left and right steered wheels of the vehicle. It is characterized in that the wheel speed ratio of the steered wheels is obtained and the restoration compensation signal is output.

[0012]

According to the invention of claim 6 , the inventions of claims 1 to
In the electric power steering apparatus according to any one of 5 above, the signal generating means detects the disconnection state of the signal line based on a signal input from a control device that performs the other control (SD1 to SD1). It is characterized by having SD7). According to the invention described in claim 7 , in the electric power steering device according to claim 6 ,
The signal generating means is characterized by having means (SD9) for stopping the torque assist by the motor when the disconnection is detected.

In the invention described in claim 8 , claims 1 to
In the electric power steering device according to any one of 7 above, the control device that performs other control of the vehicle is a control device that performs brake control of the vehicle. The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means described in the embodiments described later.

[0015]

According to the invention described in claims 1 to 8 , the steering is restored to the neutral position based on the wheel speed of the left and right steered wheels of the vehicle. Therefore, the restoration control to the neutral position can be performed using the wheel speed without using the steering angle sensor. In particular, such a wheel speed can be obtained by a signal input from another control device, and the configuration can be simplified by using a signal from another control device.

[0016]

【Example】

(First Embodiment) FIG. 1 is a configuration diagram showing a main configuration of an electric power steering apparatus according to a first embodiment of the present invention. In FIG. 1, a torque sensor 1 for detecting a steering torque is provided at a base portion of a steering shaft 12a to which a steering wheel 12 is attached, and a right steering wheel 10 and a left steering wheel 1 are provided.
The speed reducer 15 is connected to the rack shaft 16 that connects the drive shaft 1 and the motor 13. The motor 13 that assists the steering force is connected to the speed reducer 15 via the electromagnetic clutch 14. Right steering wheel 10
The left steered wheel 11 is provided with wheel speed sensors 18 and 19 for detecting wheel speed signals, respectively.

The steering torque applied to the steering wheel 12 is detected by the torque sensor 1. The torque sensor 1 has a predetermined voltage level when the steering torque is zero, and has a voltage that increases when a right steering force is applied and decreases when a left steering force is applied. It outputs a steering torque signal of proportional DC voltage. Then, based on this steering torque signal, torque servo control for supplying an assist current to the motor 13 is performed by a torque servo system having an analog circuit configuration from the phase compensation filter 2 to the current detection unit 9.

Further, there is provided a microcomputer (hereinafter referred to as a microcomputer) 20 which outputs control parameters for performing the restoration control to the neutral steering angle and the vehicle speed sensitive control. The microcomputer 20 indicates the restoration compensation torque. The first pulse signal of the duty ratio and the second pulse signal of the duty ratio indicating the gain for vehicle speed sensitivity are output to the addition calculation unit (restoration compensation unit) 3 and the multiplication calculation unit 5, respectively. Microcomputer 2 that outputs the first and second pulse signals
The calculation processing of 0 will be described later.

The torque servo control using the first and second pulse signals as control parameters will be described below. The steering torque signal from the torque sensor 1 is subjected to detection delay correction and noise removal by the phase compensation filter 2, and is input to the addition calculation unit 3. In addition, the microcomputer 2
The first pulse signal from 0 is also input to the addition calculation unit 3 via the buffer 21. Here, the signal output from the phase compensation filter 2 is called a signal Vt, and the first pulse signal is called a signal Doff.

FIG. 2 shows a specific circuit of the addition operation unit 3. The addition arithmetic unit 3 is an operational amplifier (differential inverting amplifier).
It is composed of 30, resistors 32 to 36, and a capacitor 37. The signal Doff is input to the smoothing circuit including the resistors 34 to 36 and the capacitor 37. Signal Doff
The resistor 36 is connected in parallel with the resistor 34 while the signal is at "high" level, and the resistor 36 is connected in parallel with the resistor 35 while the signal Doff is at "low" level. Therefore, the resistance 34
And the voltage at the branch point Voff of 35 is the value of the resistor 36 and the signal D
It is changed by the duty ratio of off, smoothed by the capacitor 37, and applied to the (+) terminal of the operational amplifier 30. That is, the signal Doff passing through the resistor 36
Is smoothed by the capacitor 37 and becomes a DC signal (offset voltage) Voff.
Input to the terminal.

The operational amplifier 30 adds the DC signal Voff and the signal Vt and outputs a signal Vout. That is, the signal Vt corresponding to the steering torque signal from the torque sensor 1
Is output as a signal to which an offset has been added by the signal Doff, that is, a voltage that has been DC-shifted. The resistance value of the resistor 36 is set to a value sufficiently larger than the resistance value of each of the resistors 34 and 35, and limits the variation width of the offset voltage. As a result, even if the microcomputer 20 goes out of control and the signal Doff becomes an abnormal value, it is possible to prevent the abnormal assist torque from being generated.

Then, the signal Vout is input to the assist torque calculation unit 4. A specific circuit of the assist torque calculation unit 4 is shown in FIG. The signal Vout shown in (a) is input to the comparator 42 and compared with the reference potential 49, and the rotation direction of the motor 13 is determined by the comparison result. The signal whose rotation direction has been determined is output as the rotation direction signal 40.

The signal Vout is the operational amplifiers 43, 4
The signal is input to the absolute value circuit A composed of 4 and the like, and is converted into a signal in which the portion of the signal shown in (a) below the reference potential is inverted with respect to the reference potential. This converted signal becomes the signal shown in (b). And the signal (b) is
It is converted into a signal shown in (c) by a circuit composed of the resistors 46 and 47, the differential inverting amplifier 45, the diodes D1 and D2, etc., and the assist torque calculator output 41 (assist torque signal, hereinafter referred to as Vtrq) Is output as.

This signal (c) is clamped at the reference potential as shown in the figure, and the clamping range is set by the resistors 46 and 47. In the clamp range, the dead zone is where torque assist is not performed.
The output signal Vtrq of the assist torque calculation unit 4 is input to the multiplication calculation unit 5. On the other hand, the second pulse signal (hereinafter, referred to as signal Dvgain) of the duty ratio indicating the gain for the vehicle speed response from the microcomputer 20 is also input to the multiplication calculation unit 5. FIG. 4 shows a specific circuit configuration of the multiplication calculation section 5.

In FIG. 4, the signal Vtrq is the resistance 51,
The signal Dvgain from the microcomputer 20 is input to the operational amplifier 50 through the FET 52 and the FET through the resistor 55.
It is input to the gate of 52. Here, the resistors 51, 55 and the FET 52 constitute a switching circuit,
The operational amplifier 50, the resistor 53, and the capacitor 54 form an inverting amplifier circuit.

The FET 52 performs a switching operation according to the input level of the signal Dvgain. The voltage applied to the inverting amplifier circuit of the signal Vtrq is controlled according to this switching operation. That is, the switching operation of the FET 52 produces a signal obtained by multiplying the duty ratio of the signal Dvgain by the signal Vtrq. This signal is amplified by the inverting amplifier circuit.

This inverting amplifier circuit is composed of a capacitor 54, and outputs a DC signal VI by its operation. The DC signal VI is VI = Vtrq · Duty
It is represented by. Therefore, the gain of the signal Vtrq is
It is changed according to the duty ratio of ain, that is, the vehicle speed. The signal output from the multiplication calculation unit 5 is converted into a current command value for the motor 13 in the current setting unit 6. In this case, the value of the assist current is set according to the difference between the reference potential described above and the DC signal VI output from the multiplication calculator 5. Then, based on the set assist torque value, an assist current is supplied to the motor 13 by a minor loop of constant current control composed of the current deviation compensation calculator 7, the motor driver 8 and the current detector 9. As a result, the assist torque control by the motor 13 is performed.

FIG. 5 shows the relationship between the assist current and the steering force. (A) shows a basic pattern when the vehicle is in a straight traveling state. The basic pattern shown in (a) is shifted to the left and right in the drawing by the offset voltage (Voffset) by the first pulse signal, that is, the restoration compensation value according to the steering angle and the vehicle speed. That is, when the vehicle is steered to the right, the pattern shown in (b) is obtained, and when the vehicle is steered to the left, the pattern shown in (c) is obtained.

Restoration control to the neutral steering angle is performed by such a shift. For example, if the user releases the hand holding the steering wheel while steering to the right, the steering force becomes "0", so that the left assist current (-i) flows. This left assist current restores the steering to the neutral position. The portion in which the assist current does not flow is a dead zone for preventing excessive assist when the steering force is smaller than a predetermined value (close to “0”). As described above, it is determined by the partial pressure of the resistors 46 and 47 in the assist torque calculation unit 4.

In addition, in the multiplication operation unit 6, the signal Vtrq
Since the gain is changed according to the vehicle speed, the assist current changes with a larger gain at lower speeds as shown in FIG. 6, and so-called vehicle speed sensitive assist control can be performed. Next, the arithmetic processing performed by the microcomputer 20 will be described. The microcomputer 20 performs arithmetic processing for outputting the first and second pulse signals for performing the above-described neutral steering angle restoration control and vehicle speed response control. This arithmetic processing will be described based on the flowchart of FIG.

First, the left and right wheel speed pulses are read from the wheel speed sensors 18 and 19 (step SA1), and the left and right wheel speeds are calculated from the left and right wheel speed pulses (step SA2). Then, the average vehicle speed Vav is calculated based on the calculated left and right wheel speeds (step SA3).
Subsequently, an estimation calculation of the steering angle θ is performed based on the ratio of the left and right wheel speeds obtained in step SA2 (step S
A4). A map showing the relationship between the left and right wheel speed ratios and the steering angle θ is stored in the microcomputer 20, and the steering angle θ corresponding to the left and right wheel speed ratios is extracted.

Then, in the next step SA5, the torque (restoration compensation value) for restoration compensation to the neutral steering angle is obtained based on the average vehicle speed Vav and the steering angle θ, and the first duty ratio corresponding to the restoration compensation value is calculated. Create and output a pulse signal. Here, since the restoration compensation value is for compensating the restoration against the centrifugal force during turning of the vehicle, it is expressed as a function based on the vehicle speed and the steering angle, that is, f (Vav, θ). This function is stored as a map. Therefore, the duty ratio indicating the restoration compensation value is set from the steering angle and the vehicle speed using the map, and the first pulse signal having the duty ratio is output.

At the next step SA6, a gain for vehicle speed sensitivity is obtained, and a second pulse signal having a duty ratio corresponding to this gain is created and output. Here, the gain of the vehicle speed response is expressed as a function k (Vav) based on the vehicle speed Vav. This function is stored as a map, so that the map is used to set the duty ratio indicating the gain of the vehicle speed response from the vehicle speed, and the second pulse signal having that duty ratio is output.

Based on the first and second pulse signals output in steps SA5 and SA6, the addition operation unit 3,
The above-described processing is performed in the multiplication calculator 5. The frequencies of the first and second pulse signals output from the microcomputer 20 are compared with the control response frequency of the analog torque servo system configured by the phase compensation filter 2 or the current detection unit 9.
Each of the first pulse signal and the second pulse signal is set to a value that can be sufficiently smoothed as a direct current. For example, if the frequency of the signal Dvgain is set to a value 10 times or more the control response frequency of the torque servo system, smoothing is performed. Even if the capacitance of the capacitor 54 is reduced, it can be sufficiently functioned as a DC signal. (Second Embodiment) Next, a case where the present invention is applied to a vehicle equipped with an ABS (anti-lock brake system) will be described. FIG. 8 shows the overall configuration.

In FIG. 8, reference numeral 30 is a microcomputer for performing ABS control. In the ABS control, the brake control is performed based on the wheel speed of each wheel. Therefore, in this embodiment, the wheel speed is used to obtain the information on the steering angle θ and the vehicle speed Vav necessary for the above-described restoration control to the neutral steering angle and the vehicle speed response control. Therefore, ABS
The microcomputer 30 calculates the steering angle θ and the vehicle speed Vav,
It has a function of sending out as a PWM signal having such information. That is, as will be described later, a PWM signal that represents the vehicle speed Vav as a frequency and the steering angle θ as a duty ratio is output.

In the ABS microcomputer 30, the arithmetic processing of the portion for outputting the information on the steering angle θ and the vehicle speed Vav will be described with reference to the flowchart shown in FIG. Steps SB1 to SB3 are the same as step S in FIG.
The same processing as A1 to SA3 is performed. Then, the frequency F of the PWM signal to be generated is calculated based on the average wheel speed Vav (step SB4). The average wheel speed Vav
The relationship between the frequency F and the frequency F is stored as a map in the microcomputer 30, and the frequency F corresponding to the average wheel speed Vav is stored.
Are to be extracted.

In the next step SB5, the inner / outer wheel speed ratio (VR / VL) and the duty ratio D of the PWM signal to be generated are obtained from the left and right wheel speeds VR and VL. The inner / outer wheel speed ratio (VR / VL) is related to the steering angle θ, and the duty ratio D corresponding to the steering angle θ is extracted from the inner / outer wheel speed ratio (VR / VL) using a map (step SB5). ).

Then, in step SB6, a PWM signal of the extracted frequency F and duty ratio D is generated, and in step SB7 the PWM signal is output. An example of this PWM signal is shown in FIG. When the vehicle has a speed ratio of the inner and outer wheels of 1, that is, when the vehicle is in a straight traveling state, a PWM signal having a duty value of 50% is output when the vehicle is in the right turning state as shown in FIG. 10A. , The duty value is smaller than 50% as shown in FIG.
For example, when the vehicle is in the left turning state, the duty ratio of the PWM signal of 25% is 50% as shown in FIG.
A larger PWM signal, for example 75%, is generated and output.

The frequency of the PWM signal is shown in FIG.
As shown in, the minimum frequency f0 is set to a value that proportionally changes corresponding to the average wheel speed Vav. Therefore, the average wheel speed Vav of the vehicle and the steering angle θ are set to one PWM.
It can be output as a signal. This P output
The WM signal is input to the signal separation unit 40 including a microcomputer. FIG. 12 shows the arithmetic processing of the signal separation unit 40.

First, in step SC1, the PWM signal output from the ABS microcomputer 30 is read, the steering angle θ is extracted from the duty ratio of the PWM signal, and P
The average wheel speed Vav is extracted from the WM frequency. Then, based on the average wheel speed Vav and the steering angle θ, in steps SC2 and SC3, the first and second pulse signals are created and output as in steps SA5 and SA6 of FIG. 7 in the first embodiment. .

As described above, in the vehicle provided with the ABS, the wheel speed sensor is already provided,
Since the microcomputer 30 that performs S control has a function of calculating the wheel speed, the PWM signal can be easily generated by using the calculation result. In addition,
When the ABS is operating, the driver does not need the restoration control when the steering wheel is released because the driver firmly holds the steering wheel for the emergency avoidance operation. Therefore, even if the ABS microcomputer 30 is used for steering restoration control when the ABS is not in operation, there is no problem.

Further, in this embodiment, since the signal is transmitted between the ABS microcomputer 30 and the signal separating section 40 by using the signal line, the signal separating section 40 detects the disconnection of the signal line. I have to. The disconnection detection process performed by the signal separation unit 40 is shown in FIG. First, ABS
The PWM signal from the microcomputer 30 is read (step SD1), and it is determined whether the PWM signal is output (step SD2). When the PWM signal is output, the on time t1 and the off time t0 of the PWM signal are read (step SD3). Then, the frequency f of the PWM signal is calculated based on the on-time t1 and the off-time t0 (step SD4).

Here, as shown in FIG. 11, since the frequency of the PWM signal is set to the minimum frequency f0 or higher,
If the frequency f obtained in step SD4 is lower than the lowest frequency f0, it can be estimated that the wire is broken or noise is mixed. Therefore, it is determined whether the frequency f is equal to or higher than the minimum frequency f0 (step SD5). Then, based on the on time t1 and the off time t0, the PWM
The duty ratio D of the signal is calculated (step SD6).
Then, it is determined whether the duty ratio D is within a predetermined range (step SD7). If it is not within the range of the predetermined size, it can be estimated that there is a failure due to disconnection or that noise is mixed. That is, even if the frequency f is equal to or higher than the minimum frequency f0, if the duty ratio D is not a normal value, it is determined that a failure due to disconnection has occurred.

When the process proceeds from step SD7 to step SD8, the electromagnetic clutch continues to be turned on assuming that there is no disconnection failure.
When the abnormality is determined in 2, SD5, SD7, the electromagnetic clutch 14 is turned off. Since the electromagnetic clutch 14 is turned off when an abnormality such as disconnection occurs in this way, the driver can perform manual steering without being affected by the motor 13.

In the second embodiment, the information on the average wheel speed Vav and the steering angle θ is obtained from the ABS microcomputer 30, but the vehicle is controlled by the left and right wheel speed signals other than the ABS control. If there is a control device, the information on the average wheel speed Vav and the steering angle θ may be obtained from the control device. Although the steering angle θ is obtained from the left / right wheel speed ratio, the left / right wheel speed is used as it is, or the left / right wheel speed is processed into information other than the ratio to obtain a map, etc. The steering angle θ may be obtained from

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a main configuration of a first embodiment.

FIG. 2 is a circuit diagram of an addition calculation unit 3.

FIG. 3 is a circuit diagram of an assist torque calculation unit 4.

FIG. 4 is a circuit diagram of a multiplication calculator 5.

FIG. 5 is a graph showing the relationship between steering force and assist current.

FIG. 6 is a graph showing the relationship between steering force, vehicle speed, and assist current.

FIG. 7 is a main flowchart of the microcomputer of the first embodiment.

FIG. 8 is a configuration diagram showing a main configuration of a second embodiment.

FIG. 9 P of the ABS microcomputer 30 in the second embodiment
It is a flow chart which shows WM signal output processing.

FIG. 10: PWM output from the ABS microcomputer 30
It is a waveform diagram of a signal, (a) duty ratio is 50%
PWM signal of (P) with a duty ratio of 25% in (b)
WM signal, (c) PWM with a duty ratio of 75%
Signals are shown respectively.

FIG. 11 is a graph showing the relationship between wheel speed and vehicle speed frequency.

FIG. 12 is a flowchart showing the first and second pulse signal output processing of the signal separation unit 40.

FIG. 13 is a flowchart showing a disconnection detection process of the signal separation unit 40.

[Explanation of symbols]

1 ... Torque sensor, 14 ... Electromagnetic clutch, 15 ...
Speed reducer, 18, 19 ... Wheel speed sensor, 20 ... Microcomputer, 30 ... ABS microcomputer, 40 ... Signal separation unit.

Continuation of front page (56) Reference JP-A-2-195224 (JP, A) JP-A-61-98674 (JP, A) JP-A-4-38419 (JP, A) JP-A-62-85763 (JP , A) JP-A-2-164664 (JP, A) JP-A-5-278593 (JP, A) JP-A-6-56015 (JP, A) JP-A-6-122376 (JP, A) JP-A-6-122376 (JP, A) 6-255506 (JP, A) JP-A-6-212142 (JP, A) JP-A-62-279169 (JP, A) JP-A-63-258269 (JP, A) JP-A-62-105775 (JP, A) A) Japanese Patent Publication 6-29032 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) B62D 5/00-5/30 B62D 6/00

Claims (8)

(57) [Claims] 1. A steering torque signal which is provided with a motor for generating an assist torque for steering a steering wheel of a vehicle, and steering torque detecting means for detecting a steering torque of the steering wheel and outputting a steering torque signal. the electric power steering apparatus for controlling the assist torque by the motor based on, provided with a restoring compensation means for restoring the steering based on the wheel speed of steered wheels of the right and left of the vehicle to the neutral position, the restoring compensation means , Based on the wheel speed of the left and right steered wheels
Restoration compensation signal for generating restoration compensation torque
A signal generating means for outputting said steering torque signal by the outputted restored compensation signal
Signal conversion means for converting the signal into a signal subjected to restoration compensation, and the signal generating means is configured to control the wheel speed of the left and right steered wheels of the vehicle.
From the control device that performs other control of the vehicle based on
The signal for determining the speed ratio is input via the signal line.
The input signal is used to output the restoration compensation signal.
An electric power steering device characterized by being a force . 2. A motor for generating an assist torque for steering a steering wheel of a vehicle, steering torque detecting means for detecting a steering torque of the steering wheel and outputting a steering torque signal, and wheel speeds of left and right steered wheels of the vehicle. And a signal generation means for outputting a vehicle speed sensitive gain signal indicating a gain for vehicle speed sensitivity based on the traveling speed of the vehicle, as well as outputting a signal for recovery compensation based on And a conversion means for converting the output steering torque signal into a restored-compensated signal by the restoration-compensating signal, and determining the rotational driving direction of the motor based on the restored-compensated signal and driving the motor. For calculating the assist torque signal, and the gain of the output assist torque signal. Gain changing means for changing the gain according to the vehicle speed sensitive gain signal, and motor driving means for driving the motor based on the magnitude of the assist torque signal having the changed gain and the determined rotational driving direction of the motor. And the signal generating means includes wheel speeds of the left and right steered wheels of the vehicle.
From the control device that performs other control of the vehicle based on
The signal for determining the speed ratio is input via the signal line.
The input signal is used to output the restoration compensation signal.
An electric power steering device characterized by being a force . 3. The steering torque signal is a DC signal that changes in proportion to the steering torque, and the converting means DC-shifts the steering torque signal by the restoration compensating signal. The electric power steering device according to claim 1 or 2 . 4. The signal generating means outputs a pulse signal having a duty ratio indicating the restoration compensation torque, wherein the converting means converts the pulse signal into a DC signal, and the steering torque is generated by the DC signal. The electric power steering apparatus according to claim 3 , wherein the signal is shifted in a direct current manner. 5. The signal compensating means obtains a wheel speed ratio of the left and right steered wheels from a wheel speed signal from a wheel speed detecting means for detecting wheel speeds of the left and right steered wheels of the vehicle, and performs the restoration compensation. The electric power steering apparatus according to any one of claims 1 to 4 , which outputs a signal. 6. The signal generating means has a detecting means for detecting a disconnection state of the signal line based on a signal input from a control device for performing the other control . The electric power steering device according to any one of claims. 7. The electric power steering apparatus according to claim 6 , wherein the signal generating means has means for stopping torque assist by the motor when the disconnection is detected. 8. A control device for performing other control of the vehicle,
The electric power steering apparatus according to any one of claims 1 to 7, characterized in that a control device for performing brake control of the vehicle.