JPH11263239A - Steering device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering device for vehicle without giving a sense of incompatibility to the steering feeling while supplying the assit torque from an electric motor to a steering system in a device provided with an operation recognizing unit for checking the operation of a driving circuit for driving an electric motor provided in a steering system by eliminating the operation check of the driving circuit during the traveling of the vehicle. SOLUTION: An operation recognizing unit 22 supplies the operation recognizing signal 22a to a driving circuit 30 through an output selecting circuit 24 so as to check the operation of each field-effect transistors Q1-Q4 and each current detecting units 14, 15 in the only case where the stop condition of a vehicle is recognized on the basis of a car speed 13a detected by a car speed detecting unit 13 in the initial condition that an ignition switch 16 is operated for closing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering apparatus for a vehicle, and more particularly, to an apparatus for checking the operation of a drive circuit for driving an electric motor provided in a steering system. By not checking the operation of the drive circuit while driving,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering apparatus for a vehicle in which a current is supplied to an electric motor in accordance with an operation check of a drive circuit, and an auxiliary torque from the electric motor is supplied to a steering system so as not to give a feeling of strangeness to steering.

[0002]

2. Description of the Related Art There is known a vehicle steering apparatus such as an electric power steering apparatus in which an electric motor is provided in a steering system and a steering assist torque is supplied from the electric motor to the steering system to reduce a driver's steering force. ing. FIG. 1 is a schematic structural view of an electric power steering device as a specific example of a vehicle steering device. The electric power steering device 1 includes an electric motor 10 in a steering system, and controls the power supplied from the electric motor 10 by using the control device 20 to reduce the steering force of the driver.

[0003] A steering shaft 3 integrally provided on a steering wheel (handle) 2 includes a universal joint 4.
The rack & pinion mechanism 5 is connected to a pinion 6 via a connection shaft 4 having a and b. The rack shaft 7 includes rack teeth 7a that mesh with the pinion 6. The rack and pinion mechanism 5 converts the rotation of the pinion 6 into a reciprocating motion of the rack 7 in the axial direction. Left and right front wheels 9 as rolling wheels are connected to both ends of the rack shaft 7 via tie rods 8. When the steering wheel 2 is steered, the front wheels 9 swing through the rack and pinion mechanism 5 and the tie rods 8. Thereby, the direction of the vehicle can be changed.

In order to reduce the steering force, a motor 10 for supplying a steering assist torque (assist torque) is connected to a rack shaft 7.
The rotation output of the electric motor 10 is converted into a thrust through a ball screw mechanism 11 provided substantially parallel to the rack shaft 7 so as to act on the rack shaft 7. Electric motor 1
The drive side helical gear 10a is provided integrally with the rotor 0. The helical gear 11b and the drive-side helical gear 10a are provided integrally with the shaft end of the screw shaft 11a of the ball screw mechanism 11, and mesh with each other. The nut 11c of the ball screw mechanism 11 is connected to the rack shaft 7.

A manual steering torque acting on the pinion 6 is detected by a steering torque detector (steering torque sensor) 12 provided in a steering box (not shown).
A steering torque signal Tp corresponding to the detected steering torque is supplied to the control device 20. The control device 20 operates the electric motor 10 using the steering torque signal Tp as a main signal,
The output power (steering assist torque) of the electric motor 10 is controlled.

FIG. 2 is a block diagram showing a specific example of a conventional control device. The conventional control device 20J includes a control unit 21J, a drive circuit 30, an ignition switch open / closed state detection circuit 41, and a stabilized power supply circuit (REG) 42.
A power-on reset circuit (POR) 43, a power supply continuation circuit 44, a relay drive circuit 45, a relay 46,
It comprises diodes 47, 48 and 49 for preventing reverse voltage. The control unit 21J includes an operation confirmation unit 22J, a steering assist torque control unit 23, and an output selection unit 24. The drive circuit 30 includes a gate drive circuit 31 and a field effect transistor (FET) bridge circuit 32.

The field effect transistor (FET) bridge circuit 32 includes four power N-channel enhancement type MOS field effect transistors (FETs) Q1 to Q4 connected in a bridge. The gate drive circuit 31 outputs each drive signal 2 output from the output selection unit 24 in the control unit 21J.
4a, each field effect transistor (FET) Q
By controlling the supply of the gate power to each of the gates 1 to Q4, each of the field effect transistors (FETs) Q1 to Q4
Control of the conduction / non-conduction state of.

Reference numeral 10 denotes an electric motor, reference numeral 12 denotes a steering torque detector, reference numeral 13 denotes a vehicle speed detector, reference numeral 14 denotes a motor current detector, reference numeral 15 denotes a drive circuit current detector, reference numeral 16 denotes an ignition switch, and reference numeral 17 denotes a battery. Power supply. By providing the motor current detector 14 in series with the motor 10, the current flowing through the motor 10 is detected. The motor current signal 14a, which is a current detection output signal of the motor current detector 14, is supplied to the operation confirmation unit 22J and the steering assist torque control unit 23. By providing the drive circuit current detector 15 in series with the field effect transistor (FET) bridge circuit 32, the current flowing through the field effect transistor (FET) bridge circuit 32 is detected. The drive circuit current signal 15a, which is the current detection output signal of the drive circuit current detector 15,
2J.

When the ignition switch 16 is operated in the closed state, the battery power supply 17 is switched from the ignition switch 16 to the diode 48 via the stabilized power supply circuit (RE).
G) 42 is provided. Stabilized power supply circuit (REG) 42
Is a circuit power supply VCC whose output voltage is stabilized at, for example, 5 volts by receiving power supply from the battery power supply 17.
Is output. The circuit power supply VCC is supplied to a control unit 21J, a power-on reset circuit (POR) 43, and an ignition switch open / closed state detection circuit 41. The power-on reset circuit (POR) 43 is provided with a circuit power supply VC.
The power-on reset signal 43a is output for a preset reset time after the supply of C. The power-on reset signal 43a is supplied to the operation confirmation unit 22J and the steering assist torque control unit 23.

An ignition switch open / closed state detection circuit 41 includes a base resistor R1 and an emitter-grounded NPN.
It includes a transistor Q5 and a collector pull-up resistor R2. When the ignition switch 16 is in the closed state, the diode 47 → the NPN through the base resistor R1.
The base current is supplied to the transistor Q5, and the collector-emitter of the NPN transistor Q5 becomes conductive. As a result, the ignition switch open / closed state detection circuit 41 outputs an L level ignition switch closed state signal 41a. When the ignition switch 16 is opened, the NPN transistor Q5 is turned off, and an H-level ignition switch open state signal 41a is output via the collector pull-up resistor R2. Ignition switch open / close status signal 4
1a is supplied to the operation confirmation unit 22J and the steering assist torque control unit 23.

When receiving the power-on reset signal 43a, the operation confirmation unit 22J supplies an H-level power supply continuation command signal 22c to the power supply continuation circuit 44. The power supply continuation circuit 44 includes a base resistor R3 and an emitter-grounded NP.
It comprises an N transistor Q6, a base resistor R4, a PNP transistor Q7, and a diode D1. The emitter of PNP transistor Q7 is connected to battery power supply 17 via diode 49. PNP transistor Q
The collector of 7 is connected to a stabilized power supply circuit (REG) 42 via a diode D1.

When the power supply continuation command signal 22c at the H level is supplied to the power supply continuation circuit 44, the base current is supplied to the NPN transistor Q6 via the base resistor R3 and the N
The collector-emitter of the PN transistor Q6 becomes conductive, a current is drawn from the base of the PNP transistor Q7 via the base resistor R4, and the collector-emitter of the PNP transistor Q7 becomes conductive. PN
Due to the conduction of the P transistor Q7, the diode 49 →
A circuit for supplying the battery power supply 17 to the stabilized power supply circuit (REG) 42 is formed on the path from the PNP transistor Q7 to the diode D1. Therefore, while the H-level power supply continuation command signal 22c is being output from the operation confirmation unit 22J, even if the ignition switch 16 is operated in the open state, the stabilized power supply circuit (RE)
G) The battery power supply 17 can be supplied to 42, and the operation of the control device 20J can be continued.

When receiving the power-on reset signal 43a, the operation confirmation unit 22J supplies an L-level output selection command signal 22b to the output selection unit 24. Output selector 2
Reference numeral 4 denotes each drive signal 2 output from the operation confirmation unit 22J when the L-level output selection command signal 22b is supplied.
2a is supplied to the drive circuit 30. When the H-level output selection command signal 22b is supplied, each drive signal 23a output from the steering assist torque control unit 23 is supplied to the drive circuit 30. By supplying an L-level output selection command signal 22b from the operation confirmation unit 22J to the output selection unit 24, the operation of the drive circuit 30 can be controlled based on each drive signal 22a generated by the operation confirmation unit 22J.

Next, the operation confirmation section 22J outputs an H-level relay drive command signal 22d. The relay drive command signal 22d may be output before the output selection command signal 22b at the L level is output, or the relay drive command signal 2d may be output.
2d and the output selection command signal 22b may be output simultaneously. The relay drive command signal 22d is supplied to the relay drive circuit 45.

The relay drive circuit 45 includes a base resistor R5
And an emitter-grounded NPN transistor Q8. When an H-level relay drive command signal 22d is output from the operation confirmation unit 22J, N is output via the base resistor R5.
The base current is supplied to the PN transistor Q8, and the NPN
The conduction between the collector and the emitter of the transistor Q8 is established. When the NPN transistor Q8 becomes conductive, the exciting current of the exciting winding 46a of the relay 46 is supplied through the path of the battery power supply 17 → the diode 49 → the exciting winding 46a of the relay 46 → the NPN transistor Q8 → the vehicle body ground.
The open contact 46b of the relay 46 becomes conductive. When the contact 46b of the relay is turned on, the battery power supply 17 is supplied to the drive circuit 30 so that a current can be supplied to the electric motor 10 via the drive circuit 30.

Next, the operation confirmation unit 22J outputs a drive signal 22a for turning on only the field effect transistor (FET) Q1 and monitors the detection output of each of the current detectors 14 and 15. The operation confirmation unit 22J is connected to the motor current detector 14
When the motor current is detected, it is determined that a failure (on failure) in which the field-effect transistor (FET) Q4 is turned on has occurred. Operation check part 22J
When a driving circuit current is detected only by the driving circuit current detector 15, a field effect transistor (FET) Q
It is determined that a failure (on-failure) in which a conduction state occurs in 3 has occurred. When an ON failure is detected, the operation confirmation unit 22J stores the failure content in a failure content storage unit (not shown). The operation confirmation unit 22J stops outputting the relay drive command signal 22d when the ON failure is detected. The operation check unit 22J also stops outputting the power supply continuation command signal 22c.

The operation confirming unit 22J outputs a drive signal 22a for turning on only the field effect transistor (FET) Q2.
And monitors the detection output of each of the current detectors 14 and 15. When the motor current is detected by the motor current detector 14, the operation check unit 22J determines that a failure (on failure) in which the field-effect transistor (FET) Q3 is turned on has occurred. When the drive circuit current is detected only by the drive circuit current detector 15, the operation check unit 22J determines that a failure (on failure) in which the field effect transistor (FET) Q4 is turned on has occurred. . When an ON failure is detected, the operation confirmation unit 22J stores the failure content in a failure content storage unit (not shown).
The operation confirmation unit 22J stops outputting the relay drive command signal 22d when the ON failure is detected. The operation check unit 22J also stops outputting the power supply continuation command signal 22c.

The operation confirming unit 22J outputs a drive signal 22a for turning on only the field effect transistor (FET) Q3.
And monitors the detection output of each of the current detectors 14 and 15. When the motor current is detected by the motor current detector 14, the operation checking unit 22J determines that a failure (on failure) in which the field-effect transistor (FET) Q2 is turned on has occurred. When the drive circuit current is detected only by the drive circuit current detector 15, the operation check unit 22J determines that a failure (on failure) in which the field-effect transistor (FET) Q1 is turned on has occurred. When a failure is detected, the operation confirmation unit 22J stores the failure content in a failure content storage unit (not shown). The operation confirmation unit 22J stops outputting the relay drive command signal 22d when the ON failure is detected. The operation confirmation unit 22J
Stops the output of the power supply continuation command signal 22c.

The operation confirming unit 22J outputs a drive signal 22a for turning on only the field effect transistor (FET) Q4.
And monitors the detection output of each of the current detectors 14 and 15. When the motor current is detected by the motor current detector 14, the operation checking unit 22J determines that a failure (on failure) in which the field-effect transistor (FET) Q1 is turned on has occurred. When the drive circuit current is detected only by the drive circuit current detector 15, the operation check unit 22J determines that a failure (on failure) in which the field-effect transistor (FET) Q2 is turned on has occurred. When a failure is detected, the operation confirmation unit 22J stores the failure content in a failure content storage unit (not shown). The operation confirmation unit 22J stops outputting the relay drive command signal 22d when the ON failure is detected. The operation confirmation unit 22J
Stops the output of the power supply continuation command signal 22c.

Next, the operation confirmation unit 22J includes a field effect transistor (FET) Q1 and a field effect transistor (FE).
T) A current detection operation test PWM drive signal 22a for switching operation of Q4 with a preset current detection operation test duty ratio is output. As a result, the motor 10 is driven at the PWM with the duty ratio for the current detection operation test.
Be driven. The duty ratio for the current detection operation test is set so that a relatively small current of, for example, about several amperes flows through the electric motor 10.

The operation confirmation section 22J checks whether or not a drive current corresponding to a duty ratio for a current detection operation test is detected based on the drive circuit current signal 15a output from the drive circuit current detector 15. . Further, the operation confirmation unit 22J determines whether or not the motor current corresponding to the duty ratio for the current detection operation test has been detected based on the motor current signal 14a output from the motor current detector 14, and whether the detected motor current has been detected. Check whether the polarity of the motor current is appropriate. The operation confirmation unit 22J outputs a current detection signal 14 which is a detection output of each of the current detectors 14 and 15.
When an abnormality is detected in the a and 15a, the detected abnormality is stored in a failure content storage unit (not shown), and the relay drive command signal 22d and the power supply continuation command signal 22c
Stop output of

Next, the operation confirmation unit 22J includes a field effect transistor (FET) Q2 and a field effect transistor (FE).
T) A current detection operation test PWM drive signal 22a for switching operation of Q3 with a preset current detection operation test duty ratio is output, and each current detector 1
It is checked whether there is any abnormality in the current detection signals 14a and 15a of the fourth and the fifth.

Further, the operation confirmation section 22J outputs the current detection operation test PWM drive signal 22a and outputs the relay drive command signal 22d while the motor 10 is in the PWM operation.
Is stopped and the contact 46b of the relay 46 is opened, and then the relay drive command signal 22d is output to output the relay 4b.
The contact 6 is closed. By releasing the contact 46b of the relay 46 while the current is being supplied to the electric motor 10 via the drive circuit 30, an arc discharge is generated at the contact 46b of the relay 46, and the contact 46b of the relay 46 is self-cleaned. Let The self-cleaning operation of the contact 46b may be performed before checking the current detection operation of each of the current detectors 14 and 15.

The operation confirming unit 22J, when completing the switching operation check of each of the field effect transistors Q1 to Q4, the current detection operation check of each of the current detectors 14 and 15, and the cleaning operation of the contact 46b of the relay 46, sets the H level. The output selection command signal 22b is output so that each drive signal 23a output from the steering assist torque control unit 23 can be supplied to the drive circuit 30 via the output selection unit 24, and the steering assist torque control start request The signal 22e is supplied to the steering assist torque control unit 23 to start the supply control of the steering assist torque.

The operation confirmation unit 22J stops outputting the relay drive command signal 22d and the power supply continuation command signal 22c when the steering assist torque control end signal 23c is supplied from the steering assist torque control unit 23.

After performing an initialization process based on the power-on reset signal 43a, the steering assist torque control unit 23 outputs the steering torque signal 12a output from the steering assist torque detector 12 and the output from the vehicle speed detector 13. Based on the vehicle speed signal 13a, the operation of calculating the steering assist torque supplied from the electric motor 10 and the process of calculating the electric motor current necessary to supply the steering assist torque are started. Specifically, after a target current to be supplied to the electric motor 10 is obtained based on the steering torque signal 12a (the magnitude of the steering torque and the steering direction), the current supplied to the electric motor 10 is corrected according to the vehicle speed. In this vehicle speed correction, the higher the vehicle speed, the smaller the steering assist torque.

The target motor current after the vehicle speed correction is supplied to a deviation calculation unit via a fade-in / fade-out processing unit. The fade-in / fade-out processing unit performs a fade-in process when the steering assist torque control start command signal 22e is supplied. In the fade-in process, the target motor current supplied to the deviation calculator is increased from zero toward the target motor current corrected for vehicle speed for a predetermined time. After the fade-in process ends,
The target motor current after the vehicle speed correction is directly supplied to the deviation calculation unit.

The deviation calculating unit calculates a deviation between the target motor current supplied through the fade-in / fade-out processing unit and the motor current signal 14a (current actually flowing in the motor) detected by the motor current detector 14. And a deviation signal is supplied to the PID control unit. The PID control unit performs a PID (proportional / integral / differential) process on the deviation signal, generates a drive control signal for controlling the current supplied to the electric motor 10 so that the deviation approaches zero, and generates the generated drive. The control signal is supplied to the PWM signal generator.

The PWM signal generator generates and outputs a pulse width modulated (PWM) drive signal 23a for performing the PWM operation of the electric motor 10 based on the drive control signal.
Drive signal 23 output from steering assist torque control unit 23
a is supplied to the gate drive circuit 31 via the output selection unit 24. The gate drive circuit 31 performs pulse width modulation (PW
M) The gate of each field-effect transistor is driven based on the drive signal 23a that is performed, and each field-effect transistor is switching-driven. As a result, the electric motor 10
The vehicle is driven, and a steering assist torque corresponding to the manual steering torque is supplied from the electric motor 10.

When the steering assist torque control unit 23 detects that the ignition switch 16 has been operated to the open state based on the ignition switch open / close state signal 41a, the steering assist torque control unit 23 performs a fade-out process and then terminates the steering assist torque control. The signal 23c is output. In the fade-out process, the target motor current to be supplied to the deviation calculation unit is decreased from the target motor current subjected to the vehicle speed correction to zero for a predetermined time.

When the steering assist torque control end signal 23c is supplied, the operation confirmation unit 22J outputs the relay drive command signal 2
The output of 2d is stopped to open the contact 46b of the relay 46, and the output of the power supply continuation command signal 22c is stopped to stop the power supply to the stabilized power supply circuit 42 via the power supply continuation circuit 44. Thereby, all the operations of the control device 20J are stopped.

[0032]

The conventional control device 20J shown in FIG. 2 uses the field effect transistors (FETs) Q1 to Q4 in the drive circuit 30 in an initial state in which the ignition switch 16 is operated to close. , Operation check of each current detector 14, 15 and relay contact 46b
Is performed.

Here, each field effect transistor (FE)
T) When at least one of Q1 to Q4 has an ON failure, each field effect transistor (FET) Q1 to Q4
While checking the continuity failure of Q4 and checking the operation of each current detector 14 and 15,
Further, when the self-cleaning operation of the relay contact 46b is performed, the motor current is supplied to the motor 10.

When a current is supplied to the electric motor 10 for confirming the operation, the electric motor 10 generates a torque, and the torque is transmitted to the steering wheel (handle) 2 via the ball screw mechanism 11, the rack & pinion mechanism and the like. This may cause the driver to feel uncomfortable in steering. In particular, when the driver turns off and on the ignition switch while the vehicle is running, the operation confirmation unit 22J
When the operation check operation is performed, there is a great possibility that the driver may feel uncomfortable in steering.

The present invention has been made to solve such a problem. By not checking the operation of the drive circuit while the vehicle is running, current is supplied to the electric motor in accordance with the operation check of the drive circuit. It is another object of the present invention to provide a steering apparatus for a vehicle in which an assist torque from an electric motor is supplied to a steering system so as not to give a feeling of strangeness to steering.

[0036]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a vehicle steering system according to the present invention includes an electric motor provided in a steering system of a vehicle, a drive circuit for driving the electric motor, and operation confirmation of the drive circuit. A vehicle speed detecting unit for detecting the speed of the vehicle, wherein the vehicle speed detected by the vehicle speed detecting unit is set in advance. When the value is equal to or more than the value, the operation confirmation signal is not output.

Further, a vehicle steering apparatus according to the present invention provides a motor for applying an auxiliary torque to a steering system of a vehicle, a drive circuit for driving the motor, and controls the operation of the motor via the drive circuit. And a control unit that outputs an operation confirmation signal for confirming the operation of the drive circuit.
A vehicle speed detecting unit for detecting the speed of the vehicle is provided, and the control unit is configured not to output the operation confirmation signal when the vehicle speed detected by the vehicle speed detecting unit is equal to or higher than a preset value.

The vehicle steering apparatus according to the present invention does not output an operation confirmation signal for confirming the operation of the drive circuit when the vehicle is in a running state. No confirmation is made. Therefore, current is supplied to the electric motor in accordance with the operation check of the drive circuit, and auxiliary torque from the electric motor is supplied to the steering system, so that the steering does not feel uncomfortable.

[0039]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the present embodiment,
An electric power steering device will be described as a specific example of a vehicle steering device. FIG. 3 is a block diagram of a control device for a steering device of a vehicle according to the present invention. The control device 20 shown in FIG. 3 is configured such that a vehicle speed signal 13a, which is an output signal of the vehicle speed detector 13, is supplied to an operation confirmation unit 22. The conventional control device 22J shown in FIG. And different.

The control device 20 shown in FIG.
, A drive circuit 30, an ignition switch open / closed state detection circuit 41, a stabilized power supply circuit (REG) 42, a power-on reset circuit (POR) 43, a power supply continuation circuit 44, a relay drive circuit 45, and a relay 46. And diodes 47, 48, and 49 for preventing reverse voltage. The control unit 21 includes an operation confirmation unit 22, a steering assist torque control unit 23, and an output selection unit 24. The driving circuit 30
The gate drive circuit 31 and a field effect transistor (FE)
T) a bridge circuit 32.

Reference numeral 10 denotes a motor, reference numeral 12 denotes a steering torque detector, reference numeral 13 denotes a vehicle speed detector, reference numeral 14 denotes a motor current detector, reference numeral 15 denotes a drive circuit current detector, reference numeral 16 denotes an ignition switch, and reference numeral 17 denotes a battery. Power supply. By providing the motor current detector 14 in series with the motor 10, the current flowing through the motor 10 is detected. A motor current signal 14 a, which is a current detection output signal of the motor current detector 14, is supplied to an operation confirmation unit 22 and a steering assist torque control unit 23. By providing the drive circuit current detector 15 in series with the field effect transistor (FET) bridge circuit 32, the current flowing through the field effect transistor (FET) bridge circuit 32 is detected. The drive circuit current signal 15a, which is the current detection output signal of the drive circuit current detector 15,
Supplied to

The drive circuit 30, an ignition switch open / closed state detection circuit 41, a stabilized power supply circuit (REG) 42,
The configuration and operation of the power-on reset circuit (POR) 43, the power supply continuation circuit 44, the relay drive circuit 45, and the relay 46 are the same as those shown in FIG.
Description is omitted.

When receiving the supply of the power-on reset signal 43a, the operation confirmation unit 22 supplies the power supply continuation command signal 22c of H level to the power supply continuation circuit 44. This allows
H level power supply continuation command signal 22c from the operation confirmation unit 22
Is output, the battery power supply 17 can be supplied to the stabilized power supply circuit (REG) 42 via the power supply continuation circuit 44 even if the ignition switch 16 is operated to the open state. Operation can be continued.

Upon receiving the supply of the power-on reset signal 43a, the operation check unit 22 checks whether the vehicle is in a stopped state (or a state at a predetermined vehicle speed or less) based on the vehicle speed signal 13a. When the vehicle is stopped, or when the vehicle is traveling at a low vehicle speed of, for example, several kilometers per hour or less, the operation confirmation unit 22 starts an initial check process described below.

When the vehicle is in a stopped state (or in a state where the vehicle speed is equal to or lower than a predetermined vehicle speed), the operation confirmation unit 22 supplies an output selection command signal 22b of L level to the output selection unit 24. When the output selection command signal 22b at the L level is supplied, the output selection unit 24 supplies each drive signal 22a output from the operation confirmation unit 22 to the drive circuit 30, and the output selection command signal 22b at the H level is output. When supplied, each drive signal 23a output from the steering assist torque control unit 23 is
0. By supplying an L-level output selection command signal 22b from the operation confirmation unit 22 to the output selection unit 24, the operation of the drive circuit 30 can be controlled based on each drive signal 22a generated by the operation confirmation unit 22. Each drive signal 22a generated by the operation confirmation unit 22 corresponds to an operation confirmation signal for confirming the operation of the drive circuit described in the claims.

Next, the operation confirmation unit 22 outputs a relay drive command signal 22d of H level, drives the relay 46 via the relay drive circuit 45, and makes the contact 46b of the relay conductive. When the contact 46b of the relay is turned on, the battery power supply 17 is supplied to the drive circuit 30 so that a current can be supplied to the electric motor 10 via the drive circuit 30.

Next, the operation confirming unit 22 outputs a drive signal 2 for making only the field effect transistor (FET) Q1 conductive.
2a is output, and the detection outputs of the current detectors 14 and 15 are monitored. When the motor current is detected by the motor current detector 14, the operation checking unit 22 determines that a failure (on failure) in which the field effect transistor (FET) Q4 is turned on has occurred. When the drive circuit current is detected only by the drive circuit current detector 15, the operation check unit 22 determines that a failure (on failure) in which the field-effect transistor (FET) Q3 is turned on has occurred. The operation confirmation unit 22 determines that the ON failure has been detected.
The failure content is stored in a failure content storage unit (not shown). The operation confirmation unit 22 stops outputting the relay drive command signal 22d when the ON failure is detected. In addition, the operation confirmation unit 22
Stops the output of the power supply continuation command signal 22c.

Next, the operation confirmation unit 22 outputs a drive signal 2 for turning on only the field effect transistor (FET) Q2.
2a is output, and the detection outputs of the current detectors 14 and 15 are monitored. When the motor current is detected by the motor current detector 14, the operation checking unit 22 determines that a failure (on failure) in which the field-effect transistor (FET) Q3 is turned on has occurred. When the drive circuit current is detected only by the drive circuit current detector 15, the operation check unit 22 determines that the field-effect transistor (FET) Q4 has a failure to be turned on. When an ON failure is detected, the operation confirmation unit 22 stores the failure content in a failure content storage unit (not shown). Operation check section 22
Is a relay drive command signal 22d when an ON failure is detected.
Stop output of The operation confirmation unit 22 also stops outputting the power supply continuation command signal 22c.

Next, the operation confirming unit 22 outputs the drive signal 2 for turning on only the field effect transistor (FET) Q3.
2a is output, and the detection outputs of the current detectors 14 and 15 are monitored. When the motor current is detected by the motor current detector 14, the operation checking unit 22 determines that a failure (on failure) in which the field-effect transistor (FET) Q2 is turned on has occurred. When the drive circuit current detector 15 detects the drive circuit current, the operation check unit 22 determines that a failure (on failure) in which the field-effect transistor (FET) Q1 is turned on has occurred. When an ON failure is detected, the operation confirmation unit 22 stores the failure content in a failure content storage unit (not shown). The operation confirmation unit 22 stops outputting the relay drive command signal 22d when the ON failure is detected. In addition, the operation confirmation unit 22
The output of the power supply continuation command signal 22c also stops.

Next, the operation confirming unit 22 outputs the drive signal 2 for turning on only the field effect transistor (FET) Q4.
2a is output, and the detection outputs of the current detectors 14 and 15 are monitored. When the motor current is detected by the motor current detector 14, the operation check unit 22 determines that a failure (on failure) in which the field-effect transistor (FET) Q1 is turned on has occurred. When the drive circuit current is detected only by the drive circuit current detector 15, the operation confirmation unit 22 determines that a failure has occurred in which the field effect transistor (FET) Q2 becomes conductive. When an ON failure is detected, the operation confirmation unit 22 stores the failure content in a failure content storage unit (not shown). Operation check section 22
Is a relay drive command signal 22d when an ON failure is detected.
Stop output of The operation confirmation unit 22 also stops outputting the power supply continuation command signal 22c.

Next, the operation confirmation section 22 includes a field effect transistor (FET) Q1 and a field effect transistor (FE).
T) A current detection operation test PWM drive signal 22a for switching operation of Q4 with a preset current detection operation test duty ratio is output. As a result, the motor 10 is driven at the PWM with the duty ratio for the current detection operation test.
Be driven. The duty ratio for the current detection operation test is set so that a relatively small current of, for example, about several amperes flows through the electric motor 10.

The operation confirming unit 22 includes the drive circuit current detector 1
It is checked based on the drive circuit current signal 15a output from 5 whether the drive current corresponding to the duty ratio for the current detection operation test is detected. Further, the operation confirmation unit 22 determines whether or not the motor current corresponding to the duty ratio for the current detection operation test is detected based on the motor current signal 14a output from the motor current detector 14.
Also, it is checked whether the polarity of the detected motor current is appropriate. The operation confirmation unit 22 outputs current detection signals 14a, 15
When an abnormality is detected in a, the detected abnormality is stored in a failure content storage unit (not shown), and the output of the relay drive command signal 22d and the power supply continuation command signal 22c is stopped.

Next, the operation confirmation unit 22 includes a field effect transistor (FET) Q2 and a field effect transistor (FE).
T) A current detection operation test PWM drive signal 22a for switching operation of Q3 with a preset current detection operation test duty ratio is output, and each current detector 1
It is checked whether there is any abnormality in the current detection signals 14a and 15a of the fourth and the fifth.

Further, the operation confirmation unit 22 outputs the current detection operation test PWM drive signal 22a to switch the motor 10 to P
While the WM operation is being performed, the output of the relay drive command signal 22d is stopped, and the contact 46b of the relay 46 is opened.
Close the contacts. Electric motor 1 via drive circuit 30
0 while the current is being supplied to the contact 4 of the relay 46.
By opening the contact 6b, an arc discharge is generated at the contact 46b of the relay, and the contact 46b of the relay 46 is self-cleaned. The self-cleaning operation of the contact 46b may be performed before checking the current detection operation of each of the current detectors 14 and 15.

When the operation check unit 22 completes the switching operation check of each of the field effect transistors Q1 to Q4, the current detection operation of each of the current detectors 14 and 15, and the cleaning operation of the contact 46b of the relay 46, the H level is set to H level. The output selection command signal 22b is output so that each drive signal 23a output from the steering assist torque control unit 23 can be supplied to the drive circuit 30 via the output selection unit 24, and the steering assist torque control start request The signal 22e is supplied to the steering assist torque control unit 23 to start the supply control of the steering assist torque.

After receiving the power-on reset signal 43a, the operation confirmation unit 22 stops the vehicle based on the vehicle speed signal 13a (or the vehicle is under a predetermined vehicle speed).
If it is determined that the vehicle is traveling at a speed equal to or higher than a predetermined vehicle speed, the control for supplying the steering assist torque is started without performing the above-described initial check process. In this case, the operation confirmation unit 22 outputs the H-level output selection signal 22b and outputs the drive signals 23a output from the steering assist torque control unit 23 to the drive circuit 3.
0, and outputs the relay drive command signal 22d to operate the relay 46. And
The operation confirmation unit 22 outputs the steering assist torque control start request signal 2
2e is supplied to the steering assist torque control unit 23 to start the supply control of the steering assist torque.

When the steering assist torque control end signal 23c is supplied from the steering assist torque control unit 23, the operation check unit 22 stops outputting the relay drive command signal 22d and the power supply continuation command signal 22c.

FIG. 4 is a block diagram showing a specific example of the steering assist torque control unit. The steering torque signal 12 a related to the steering torque Tp detected by the steering torque detector 12 is supplied to the target current setting unit 51. Target current setting unit 51
Outputs a target current signal 51a related to the target current IT of the electric motor set in advance corresponding to the magnitude and direction of the steering torque Tp. The target current signal 51a is supplied to a vehicle speed correction unit 52.

The vehicle speed corrector 52 performs a vehicle speed corresponding correction on the target current IT based on the vehicle speed signal 13a detected by the vehicle speed detector 13, and outputs a corrected target current signal 52a obtained by performing the vehicle speed correction. When the vehicle speed is close to zero (vehicle stopped state), the vehicle speed correction unit 52 outputs the target current IT set by the target current setting unit 51 as it is, and corrects so that the steering assist torque becomes smaller as the vehicle speed becomes higher. Perform The correction target current signal 52a has a fade-in
The data is supplied to the deviation calculation unit 54 via the fade-out processing unit 53.

Fade-in / fade-out processing section 53
Sets the target motor current 53a supplied to the deviation calculation unit 54 to zero when the power-on reset signal 43a is supplied. Then, when the steering assist torque control start command signal 22e is supplied, the fade-in / fade-out processing unit 53 performs a fade-in process. In the fade-in process, the target motor current 53a to be supplied to the deviation calculation unit 54 is increased from zero toward the value of the corrected target current signal 52a subjected to the vehicle speed correction for a predetermined time. After the end of the fade-in process, the corrected target current signal 52a subjected to the vehicle speed correction is directly supplied to the deviation calculating unit 54.

The deviation calculating section 54 includes a target motor current signal 53a supplied through the fade-in / fade-out processing section 53 and the motor current signal 14a detected by the motor current detector 14 (the current actually flowing through the motor). And a deviation signal 54a is supplied to the PID control unit 55. The PID control unit 55 outputs the deviation signal 5
4a is subjected to PID (proportional / integral / differential) processing to generate a drive control signal 55a for controlling the current supplied to the electric motor 10 so that the deviation approaches zero, and the generated drive control signal 55a is PWM The signal is supplied to the signal generator 56.

The PWM signal generation section 56 outputs the drive control signal 5
A pulse width modulated (PWM) drive signal 23a is generated and output for performing the PWM operation of the electric motor 10 based on 5a. The drive signal 23a output from the steering assist torque control unit 23 is supplied to the gate drive circuit 31 via the output selection unit 24 shown in FIG. The gate drive circuit 31
The gates of the respective field effect transistors are driven based on the drive signal 23a that has been subjected to pulse width modulation (PWM) to switch the respective field effect transistors Q1 to Q4. Thereby, the electric motor 10 is subjected to the PWM operation, and the steering assist torque corresponding to the manual steering torque is supplied from the electric motor 10.

When the fade-in / fade-out processing section 53 in the steering assist torque control section 23 detects that the ignition switch 16 has been operated to the open state based on the ignition switch open / close state signal 41a, the fade-out processing is performed. After that, a steering assist torque control end signal 23c is output. In the fade-out process,
The target motor current 53a to be supplied to the deviation calculation unit 54 is decreased from the value of the corrected target current 52a subjected to the vehicle speed correction toward zero for a predetermined time.

When the steering assist torque control end signal 23c is supplied, the operation check section 22 shown in FIG. 3 stops outputting the relay drive command signal 22d and turns off the contact 46b of the relay 46.
And the output of the power supply continuation command signal 22c is stopped, and the stabilized power supply circuit 4
The power supply to 2 is stopped. Thereby, all the operations of the control device 20 are stopped.

The operation confirmation unit 22 determines whether or not the vehicle is in a stopped state based on the vehicle speed signal 13a, and outputs each drive signal 22a as an operation confirmation signal only when the vehicle is in a stopped state. The operation of the drive circuit 30 and the current detectors 14 and 15 is checked. When the vehicle is in a running state, the drive circuit 30 and the current detectors 14 and 15 are checked.
15 is not checked. Therefore, even if, for example, the operation of opening and closing the ignition switch 16 is performed in the running state of the vehicle, the operation of the drive circuit 30 and the current detectors 14 and 15 is not checked. Therefore, the drive circuit 30 and each current detector 1
A current is supplied to the electric motor 10 in accordance with the operations 4 and 15,
The phenomenon that the torque of the electric motor 10 generated by the supply of the electric current to the electric motor 10 is transmitted to the steering system and gives a feeling of strangeness to the steering of the driver does not occur as long as the vehicle is running.

Although FIGS. 2 and 3 show a configuration in which two current detectors, that is, the motor current detector 14 and the drive circuit current detector 15, are provided, the drive circuit is not provided without the motor current detector 14. The current detector 15 may be configured to detect the motor current. Although the configuration using the field effect transistors Q1 to Q4 has been described as a specific example of the drive circuit 30, a bridge circuit for driving a motor may be configured using an insulated power bipolar transistor (IGBT).

[0067]

As described above, the vehicle steering apparatus according to the present invention does not output an operation confirmation signal for confirming the operation of the drive circuit when the vehicle is in a running state. The operation of the drive circuit is not confirmed while the vehicle is running. Therefore, the current is supplied to the electric motor in accordance with the operation check of the drive circuit, and the assist torque from the electric motor is supplied to the steering system, so that the steering does not feel uncomfortable.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of an electric power steering device as a specific example of a vehicle steering device.

FIG. 2 is a block diagram showing a specific example of a conventional control device.

FIG. 3 is a block diagram of a control device for a vehicle steering device according to the present invention;

FIG. 4 is a block diagram showing a specific example of a steering assist torque control unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device, 2 ... Steering wheel (handle), 10 ... Electric motor, 12 ... Steering torque detector, 13 ... Vehicle speed detector, 14 ... Electric motor current detector,
Reference numeral 15: drive circuit current detector, 16: ignition switch, 20: control device, 21: control unit, 22: operation confirmation unit, 22a: drive signal as operation confirmation signal, 23: steering assist torque control unit, 24: output Selection section, 30: drive circuit, 31: gate drive circuit, 32: field effect transistor bridge circuit, 41: ignition switch open / closed state detection circuit, 44: power supply continuation circuit, 45: relay drive circuit, 46: relay.

Claims (2)

[Claims] 1. A vehicle steering system comprising: an electric motor provided in a steering system of a vehicle; a drive circuit for driving the motor; and an operation confirmation unit for outputting an operation confirmation signal for confirming the operation of the drive circuit. In the above, a vehicle speed detecting unit for detecting a speed of the vehicle is provided, and the operation checking unit is configured not to output the operation checking signal when the vehicle speed detected by the vehicle speed detecting unit is equal to or higher than a preset value. Vehicle steering device. 2. An electric motor for applying an auxiliary torque to a steering system of a vehicle, a driving circuit for driving the electric motor, controlling the operation of the electric motor via the driving circuit, and confirming the operation of the driving circuit. A steering unit for outputting an operation confirmation signal for a vehicle, comprising: a vehicle speed detection unit that detects a speed of the vehicle, wherein the control unit detects that the vehicle speed detected by the vehicle speed detection unit is equal to or greater than a preset value. A steering device for a vehicle, wherein the operation confirmation signal is not output at the time.