JP2001287606A - Electronic controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely exhibit a fail-safe control function even when a control circuit board gets wet by water inundated an inside of a cabin. SOLUTION: A backup CPU 3 having the fail-safe control function in abnormality of a main CPU 2 is arranged in an upper side of the main CPU 2 in a controller for a vehicle wherein the control circuit board 1 having the main CPU 2 and the backup CPU 3 is arranged in the vicinity of a floor inside a cabin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic control unit for a vehicle in which a control circuit board is disposed in the vicinity of a floor in a vehicle compartment. The present invention relates to a vehicle electronic control device capable of reliably exhibiting a fail-safe control function.

[0002]

2. Description of the Related Art In recent years, EPS (Electric PoWer) has been used in vehicles, including fuel injection control of an engine, shift control of an automatic transmission, and control of distribution of driving force to wheels.
erSteering), auxiliary steering torque control of an electric power steering device, VGS (Varia)
2. Description of the Related Art Various types of electronic control units for a vehicle, which perform control of a change characteristic of a steering angle ratio of a variable steering angle ratio steering device, which is abbreviated as ble gear ratio steering, are mounted.

A control circuit board of this type of vehicle electronic control device usually includes a main CPU (Central Pro).
sessing Unit) and a backup C having a fail-safe control function when the main CPU fails.
PU and are arranged. This type of control circuit board is usually placed in an engine room or the like in a state where waterproof measures are taken.

[0004]

By the way, the EPS
In the control circuit board of the control device and the VGS control device,
In some cases, it is placed near the floor in the vehicle compartment without taking waterproof measures. In this case, there is no problem in the case of a vehicle with a roof because there is no danger of inundation in the vehicle interior due to rainfall,
In a vehicle with a sunroof, an open car, or the like, when the vehicle interior is flooded by heavy rain such as a shower, there is a risk that the control circuit board will be flooded and break down.

If the control circuit board of the electronic control unit for a vehicle is completely wetted, both the main CPU and the backup CPU fail and stop functioning.
When the main CPU is first wetted and stops functioning, the backup CPU can exhibit the fail-safe control function until the main CPU is wetted and stops functioning. Conversely, if the backup CPU is wetted first and stops functioning, the fail-safe control function when the main CPU is wetted and fails will no longer be executable.

Accordingly, an object of the present invention is to provide an electronic control unit for a vehicle capable of reliably exhibiting a fail-safe control function even when a control circuit board is flooded by water in a vehicle interior. I do.

[0007]

In order to solve the above-mentioned problems, the present invention is a control device for a vehicle in which a control circuit board having at least a main CPU and a backup CPU is arranged near a floor in a vehicle compartment. , The main CP
The backup CPU having a fail-safe control function at the time of abnormality of U is arranged above the main CPU.

In the control apparatus for a vehicle according to the present invention, when the control circuit board is flooded by water in the vehicle interior, the main CPU is flooded before the backup CPU. It is possible to reliably exhibit the fail-safe control function when the CPU is abnormal.

In the vehicle control device of the present invention, when the main CPU has a VGS control function and the backup CPU has a fail-safe control function of the VGS control, the backup CPU is wetted by itself. It is possible to exhibit the fail-safe control function of the VGS control before.

Further, in the vehicle control device of the present invention,
Sub C having a mutual monitoring function with the main CPU
When the PU is disposed below the backup CPU and provided on the control circuit board, when one of the main CPU and the sub CPU is wet, the monitoring function of the other CPU monitors the wet CPU. Accordingly, the backup CPU can exhibit the fail-safe control function before it is flooded. For example, a fail-safe control function of VGS control can be exhibited.

Further, in the vehicle control device according to the present invention, the power supply of the backup CPU is controlled by the main CPU.
If the power supply of the main CPU is disposed below the backup CPU and its power supply,
Since the main CPU and its power supply are flooded before the backup CPU and its power supply, the backup CPU
Further, the power supply can surely exhibit a fail-safe control function before it is flooded by itself, for example, a fail-safe control function of VGS control.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an electronic control unit for a vehicle according to the present invention. In the drawings to be referred to, FIG. 1 is a configuration diagram of a control circuit board of a vehicle electronic control device according to one embodiment in a vehicle interior, and FIG. 2 is a main C on the control circuit board of the vehicle electronic control device.
FIG. 2 is a diagram illustrating an arrangement configuration of a PU, a backup CPU, and the like.

An electronic control unit for a vehicle according to one embodiment includes:
For example, it is intended for an open car, and as shown in FIG. 1, includes a control circuit board 1 arranged near a floor F in a vehicle interior R. The control circuit board 1 includes an ECU (Electric) installed obliquely along a toe board T rising from a floor F in front of the passenger seat S.
(Control Unit). The lower edge of the control circuit board 1 is a floor F
Are arranged at a height of H from the upper surface of the.

As shown in FIG. 2, a main CPU 2, a backup CPU 3, a sub C
A PU 4, a main power supply 5 shared by the main CPU 2 and the sub-CPU 4, a backup power supply 6 for the backup CPU 3, and wet sensors 7 and 8 are provided. here,
The wet sensors 7 and 8 are arranged near the lower edge of the control circuit board 1 and are separated from each other, and the sub CPU 4 and the main power supply 5 are arranged side by side slightly above the wet sensors 7 and 8. I have. The main CPU 2 is connected to the control circuit board 1.
The backup power supply 6 is disposed above the main CPU 2 so as to face near the upper edge of the control circuit board 1. The backup CPU 3 is arranged above the main CPU 2 along with the backup power supply 6.

The main CPU 2 has an EPS control function for variably controlling an auxiliary steering torque of an electric power steering device described later, and a VGS control for variably controlling a change characteristic of a steering angle ratio of a variable steering angle ratio steering device described later. A function for monitoring the operation of the backup CPU 3;
A mutual monitoring function for monitoring the mutual operation with the PU 4 is provided as a normal function. Also, this main CP
U2 has a function of stopping the mutual monitoring function between itself and the sub CPU 4 and causing the backup CPU 3 to execute the fail-safe control of the VGS control as a function when the U2 and the sub CPU 4 are abnormal. Further, the main CPU 2
Is an EP function as a function when the backup CPU 3 is abnormal.
An assist complement control function for limiting S control to basic control and a fail-safe control function for VGS control are provided.

On the other hand, the backup CPU 3 has, as a normal function, a preparation function for preparing to immediately exhibit the fail-safe control function of the VGS control.
The backup CPU 3 has a VGS control fail-safe control function as a function when the main CPU 2 or the sub CPU 4 is abnormal. The backup CPU 3 stops its function when its own abnormality occurs.

The sub CPU 4 has, as a normal function, a mutual monitoring function of mutually monitoring the operation with the main CPU 2. The sub CPU 4 has a main C
Stop the mutual monitoring function with PU2 and back up C
It has a function of causing the PU 3 to execute the fail-safe control of the VGS control.

The water sensors 7 and 8 detect water in a state where the control circuit board 1 is energized, and output a detection signal to the main CPU 2 so that appropriate signals necessary for a short time when water is received. This is to cause the main CPU 2 to perform a treatment.

Here, the main CP of the control circuit board 1
The configuration of a steering system in which an electric power steering device under EPS control by U2 and the like and a variable steering angle ratio steering device under VGS control are incorporated will be described with reference to FIG. The steering system 10 is a so-called rack and pinion type steering system. , 14 are connected to an input shaft 15A of a variable steering angle ratio device 15. The pinion 16A of the rack and pinion mechanism 16 is formed integrally with the output shaft of the variable steering angle ratio device 15.

The rack and pinion mechanism 16 has a rack shaft 16C formed with rack teeth 16B meshing with the pinion 16A. At both ends of the rack shaft 16C, left and right steering wheels W, W of the vehicle are attached. Knuckle arm 1
7 are connected via tie rods 18, 18, respectively. A ball screw portion 19A of the ball screw mechanism 19 is formed coaxially with the rack shaft 16C. A ball nut 19B meshing with the ball screw portion 19A is fixed to a rotor 20A of an EPS motor 20 for EPS control of the electric power steering device.
The EPS motor 20 is provided with the rack shaft 16C.
Are disposed around the periphery of the body so as to pass therethrough.

Here, the variable steering angle ratio device 15 constituting the variable steering angle ratio steering device will be described with reference to FIGS. As shown in FIGS. 4 and 5, the variable steering angle ratio device 15 rotates the input shaft 15A connected to the universal joint 14 and the output shaft 15B integrally formed with the pinion 16A in an eccentric state. Built-in so-called kind of Oldham coupling freely connected, input shaft 15A
The output shaft 15B is configured to follow and rotate at a non-uniform speed with the rotation of. This variable steering angle ratio device 15 is provided in FIG.
As shown in the figure, the input shaft 15A with respect to the output shaft 15B
VGS motor 21 for VGS control that variably controls the amount of eccentricity.

As shown in FIG. 5, a coupling 15E is provided at the lower end of the input shaft 15A to movably guide the slider 15D along a guide groove 15C orthogonal to the axial direction.
Is provided. On the other hand, on the upper end surface of the output shaft 15B,
An intermediate shaft 15G that protrudes relative to the slider 15D via a tapered roller bearing 15F is protrudingly provided. The slider 15D has flat needle bearings 15H that roll along guide grooves 15C of the coupling 15E.
Is attached.

The input shaft 15A is, as shown in FIG.
It is rotatably fitted via a ball bearing 15K to a position eccentric from the center of rotation of the rotation support member 15J. The rotation support member 15J is provided with a casing 15 of the steering angle ratio variable device 15.
L is rotatably supported via a ball bearing 15M,
It is configured to be rotated in the forward and reverse directions by a rotation operation shaft 23 via a worm reduction mechanism 22.

On the other hand, as shown in FIG. 6, a rotating shaft 21A of the VGS motor 21 is configured to be transmitted to the rotating operation shaft 23 via a worm speed reduction mechanism 24. The rotation operation shaft 23 is configured to rotate the rotation support member 15J via the worm reduction mechanism 22. By rotating the rotation support member 15J via the rotation operation shaft 23 by the rotation of the VGS motor 21, the amount of eccentricity of the input shaft 15A with respect to the output shaft 15B is variably controlled. ing.

The input shaft 1 with respect to the output shaft 15B
In order to detect the amount of eccentricity of 5A and perform feedback control of the rotation of the VGS motor 21, the rotation support member 15J
A pin 24 protrudes from an upper surface of the casing 15L.
Is fixed to a displacement sensor 25 for detecting the amount of movement of the pin 24. The displacement sensor 25 is connected to the input shaft 15A.
Is detected based on the amount of movement of the pin 24, and the eccentricity signal AE is output to the electronic control unit 40 provided on the control circuit board 1.

FIG. 7 shows the relationship between the rotation angle α of the input shaft 15A of the steering angle ratio varying device 15 and the rotation angle β of the output shaft 15B. When the amount of eccentricity e of the input shaft 15A with respect to the output shaft 15B is zero, e0 is set, and e0 <e1 <e2.
When the amount of eccentricity is e0, the output shaft 15B rotates following the input shaft 15A at a constant speed, and the steering angle ratio β / α becomes 1. In the case of the eccentric amount e1, the output shaft 15B rotates following the input shaft 15A at an unequal speed, and the steering angle ratio β / α becomes smaller than 1. The same applies to the case of the eccentric amount e2, but in this case, the steering angle ratio β / α is further smaller than that of the case of the eccentric amount e1. The change characteristic of the steering angle ratio β / α in the case of the eccentric amount e2 is that the steering angle ratio β / α is particularly small in a region where the rotation angle α of the input shaft 15A is small, and that a sharp steering feeling cannot be expected. This is a characteristic with a strong so-called dull tendency, which provides a light and stable steering feeling.

Therefore, in the VGS control, the eccentricity e is reduced in order to obtain a sharp steering feeling when the vehicle is running at low speed, and the eccentricity e is increased in order to obtain a particularly stable steering feeling in high speed running. Thus, the rotation of the VGS motor 21 is controlled. Then, in the fail-safe control of the VGS control by the backup CPU 3 when the main CPU 2 fails, the rotation of the VGS motor 21 is controlled so that the eccentricity e is fixed to the maximum value in order to obtain a particularly light steering feeling.

Next, the electronic control unit 40 provided on the control circuit board 1 will be described with reference to FIG.
The electronic control unit 40 includes a steering torque input circuit 41, a vehicle speed input circuit 42 in addition to the main CPU 2, the backup CPU 3, the sub CPU 4, the main power supply (main power supply circuit) 5, and the backup power supply (backup power supply circuit) 6. , Actual eccentricity input circuit 43, gate drive circuit 44,
An EPS bridge circuit 45, a VGS bridge circuit 46, and a switching circuit 50 are provided. And this electronic control unit 4
0, the steering torque signal T from the steering torque sensor 30
S, vehicle speed signal VP from vehicle speed sensor 31, EPS motor current signal EIMO from EPS motor current sensor 32,
The VGS motor current signal VIMO from the VGS motor current sensor 33 and the eccentricity signal AE from the displacement sensor 25
Is entered.

The steering torque sensor 30 is incorporated in the variable steering angle ratio device 15 shown in FIG. 3 and sends a steering torque signal TS indicating the direction and magnitude of the manual steering torque applied to the steering system 10 to an electronic control unit. It outputs to the steering torque input circuit 41 of 40. The steering torque input circuit 41 converts the steering torque signal TS from an analog signal to a digital signal and outputs the signal to the main CPU 2 and the sub CPU 4.

The vehicle speed sensor 31 detects the number of revolutions of a transmission output shaft (not shown), and outputs the detection signal to a vehicle speed signal VP.
To the vehicle speed input circuit 42 of the electronic control unit 40. The vehicle speed input circuit 42 converts the vehicle speed signal VP from an analog signal to a digital signal,
U2, output to backup CPU3 and sub CPU4.

The EPS motor current sensor 32 includes a resistor or a Hall element connected in series with the EPS motor 20. An EPS motor current signal EIMO corresponding to the direction and magnitude of the current flowing through the EPS motor 20 is provided.
To the main CPU 2 of the electronic control unit 40. The VGS motor current sensor 33 includes a resistor or a Hall element connected in series to the VGS motor 21 and electronically controls the VGS motor current signal VIMO according to the direction and magnitude of the current flowing through the VGS motor 21. Output to the main CPU 2 of the device 40.

The displacement sensor 25 outputs an eccentricity signal AE indicating the eccentricity of the input shaft 15A with respect to the output shaft 15B of the steering angle ratio varying device 15 to the actual eccentricity input circuit 43 of the electronic control unit 40. The actual eccentricity input circuit 43 converts the eccentricity signal AE from an analog signal to a digital signal and outputs the digital signal to the main CPU 2, the backup CPU 3 and the sub CPU 4.

In order to operate the electronic control unit 40,
The main power supply (main power supply circuit) 5 includes a main CP
U2 and the sub CPU 4 allow the EPS motor 20
A power supply voltage necessary for controlling the VGS motor 21 is supplied to each unit of the electronic control unit 40. That is, the main power supply 5 supplies a power supply voltage of +5 V to the main CPU 2, the sub CPU 4, the steering torque input circuit 41, the vehicle speed input circuit 42, the actual eccentricity input circuit 43, the gate drive circuit 44, the switching circuit 50, etc. Circuit 45 and VGS
A power supply voltage of +12 V is supplied to the bridge circuit 46.

On the other hand, when the main CPU 2 or the sub CPU 4 fails, the backup power supply (backup power supply circuit) 6 supplies a power supply voltage necessary for controlling the VGS motor 21 by the backup CPU 3 to the electronic control unit 4.
0 is supplied to each part. That is, the backup power supply 6
Supplies the power supply voltage +5 V to the backup CPU 3, the actual eccentricity input circuit 43, the switching circuit 50, and the like, and supplies the power supply voltage +12 V to the VGS bridge circuit 46.

The main CPU 2, sub CPU 4, backup C
The PU 3, the gate drive circuit 44, and the switching circuit 50 will be sequentially described. First, the main CPU 2 controls the EPS to variably control the auxiliary steering torque of the electric power steering device.
It has a control function. In the EPS control, the target current value determined based on the steering torque signal TS from the steering torque sensor 30 and the vehicle speed signal VP from the vehicle speed sensor 31 and the EPS motor current signal EIMO from the EPS motor current sensor 32 are used. E detected based on
EPS motor current E actually flowing to PS motor 20
The rotation of the EPS motor 20 is controlled by feedback control so as to match IM.

That is, in the EPS control, the main C
The PU2 sets the steering torque signal TS and the vehicle speed signal VP as addresses based on data of the steering torque signal TS and the vehicle speed signal VP set in advance based on experimental values or design values and the corresponding target current values. Read the current value. Then, the main CPU 2 subtracts the EPS motor current signal EIMO from the target current value and calculates the deviation. Further, the main CPU 2 performs P (proportional), I (integral) and D (differential) control on this deviation,
PID (Proporti) indicating the direction and current value of the current supplied to the EPS motor 20 in order to make the deviation close to 0
onal Integral Differentia
l) Generate a control signal. Subsequently, the main CPU 2
Based on the PID control signal, the PWM (Puls) corresponding to the direction and current value of the current supplied to the EPS motor 20
e Width Modulation) signal, an ON signal, and an OFF signal.

The PWM signal is transmitted to the EPS bridge circuit 4
5 Power FET (Field Effect Tra)
nsistor) 45a gate G1 or power FE
The signal is input to the gate G2 of T45b, and the power FET 45a or the power FET 45b is
Drive M.

It should be noted that the PWM signal is either gate G1 or gate G
Which of the two gates is input is determined by the polarity of the deviation (PID control signal). When the PWM signal is input to the gate G1, the power FET 45d
ON signal is input to the gate G4 of the power FET 45.
d is turned on. On the other hand, when the PWM signal is input to the gate G2, the gate G3 of the power FET 45c is
Is input, and the power FET 45c is turned on. At this time, P out of the gate G1 or the gate G2
An off signal is input to the gate to which the WM signal is not input, and the power FET 45a or 45b is turned off. At this time, when the off signal is input to the gate G1, the off signal is also input to the gate G4 of the power FET 45d, and the power FET 45d is also turned off. On the other hand, when the off signal is input to the gate G2, the off signal is also input to the gate G3 of the power FET 45c,
The power FET 45c is also turned off.

EPS motor 2 by the main CPU 2
0 main drive control signal MEMS is applied to gates G1 to G4.
, An ON signal and an OFF signal to be output to the EPS bridge circuit 4 via the gate drive circuit 44.
5 is supplied.

The main CPU 2 has a VGS control function for variably controlling the change characteristic of the steering angle ratio of the variable steering angle ratio steering device. In the VGS control, the target eccentricity (corresponding to the target steering angle ratio) determined based on the vehicle speed signal VP from the vehicle speed sensor 31 and the actual eccentricity detected based on the eccentricity amount signal AE from the displacement sensor 25. The rotation of the VGS motor 21 of the variable steering angle ratio device 15 is controlled by feedback control so that the amount (corresponding to the actual steering angle ratio) matches.

That is, in the VGS control, the main C
The PU 2 reads out the target eccentricity using the vehicle speed signal VP as an address, based on the vehicle speed signal VP set in advance based on an experimental value or a design value and the data (conversion table) of the corresponding target eccentricity. Incidentally, the target eccentricity is associated with the vehicle speed signal VP by a small value at a low speed where the road surface reaction force is large, and by a large value at a high speed in order to secure stability during traveling. It is attached. Then, the main CPU 2 calculates the deviation by subtracting the actual eccentricity AE based on the eccentricity signal AE from the target eccentricity. Further, the main CPU 2 calculates P
(Proportional), I (integral), and D (differential) controls are performed to generate a PID control signal indicating the direction and current value of the current supplied to the VGS motor 21 to make the deviation close to zero.
Subsequently, the main CPU 2 generates a PWM signal, an ON signal, and an OFF signal corresponding to the direction and the current value of the current supplied to the VGS motor 21 based on the PID control signal.

The VGS motor 2 by the main CPU 2
The main drive control signal MVMS is composed of a PWM signal, an ON signal, and an OFF signal output to the gates G1 to G4 of the VGS bridge circuit 46.
It is supplied to the S bridge circuit 46. The drive control of the VGS bridge circuit 46 by the motor control signal MVMS is performed by the EPS by the main drive control signal MEMS.
Since the drive control is the same as that of the bridge circuit 45, a detailed description is omitted.

Further, the main CPU 2 has a sub CPU 4
Function to monitor operation between each other and backup C
A function of monitoring the operation of the PU3. Sub CPU4
In the mutual monitoring function with the sub C, the main CPU 2
The operation of the sub CPU 4 is monitored by comparing the vehicle speed and the like calculated by the PU 4 with the vehicle speed and the like calculated by itself, and it is determined whether the sub CPU 4 is normal or malfunctions. Then, the main CPU 2 transmits the sub CPU monitoring information to the sub CPU 4. Further, the main CPU 2 uses the main CPU monitoring information from the sub CPU 4 to generate a main signal SM by a self-monitoring function using a watchdog timer, and outputs this to the switching circuit 50.

The main signal SM is an H signal when the main CPU 2 is normal and an L signal when the main CPU 2 has failed. The main signal SM is for causing the backup CPU 3 to execute the fail-safe control function when the main CPU 2 fails. Signal. When the main CPU 2 or the sub CPU 4 fails, the main CPU 2 outputs the main signal SM as an L signal to the switching circuit 50 and outputs the V signal of the steering angle ratio variable device 15.
Backup C for fail-safe control of GS motor 21
Switch to PU3 and stop all its functions.

On the other hand, in the monitoring function of the backup CPU 3, the main CPU 2 compares the vehicle speed and the like calculated by the backup CPU 3 with the vehicle speed and the like calculated by itself, and monitors the operation of the backup CPU 3 to determine whether the backup CPU 3 is normal or faulty. Is determined. Then, the main CPU 2
The backup CPU monitoring information is transmitted to the backup CPU 3.

Backup CPU 3 or switching circuit 50
In the event of a failure, the main CPU 2 controls the EPS motor 20 of the electric power steering system to
Assist supplement control that limits S control to basic control is performed. As the control of the VGS motor 21 of the variable steering angle ratio device 15, the target eccentric amount of the variable steering angle ratio device 15 is set to the maximum amount. Then, the main CPU 2 sets V so that the actual eccentric amount AE of the steering angle ratio varying device 15 becomes the maximum eccentric amount.
The GS motor 21 is controlled, and the change characteristic of the steering angle ratio is the characteristic having the strongest tendency to be dull, that is, the characteristic that the steered wheel W is not turned much even when the steering wheel 11 is rotated greatly, and the steering is light and stable. Shift to a characteristic that gives a feeling.

Backup CPU 3 or switching circuit 50
In the failure determination of the above, when the vehicle stops, the main CPU 2 outputs the L signal as the main signal SM to the switching circuit 50 in a simulated manner, and the state in which the VGS motor current signal VIMO from the VGS motor current sensor 33 is 1 A or less continues for 10 ms. (Ie, when the VGS motor current VIM is not flowing through the VGS motor 21), the backup CPU
3 or the switching circuit 50 determines that a failure has occurred.

That is, the main CPU 2 or the sub CPU
In case of failure, the backup CPU 3 shifts the steering angle ratio characteristic of the steering angle ratio varying device 15 to the dull side.
The rotation of the VGS motor 21 is controlled. At this time, the backup CPU 3 sets the target eccentric amount to the maximum amount and performs control, so that a large VGS motor current VIM flows through the VGS motor 21. Therefore, if the VGS motor current VIM does not flow through the VGS motor 21 when the main CPU 2 falsely outputs the L signal as the main signal SM to indicate its own failure, the switching circuit 50 normally operates the main drive control signal. MVMS has not been switched to the backup drive control signal BVMS, or the backup CPU 3 has a normal backup drive control signal BVMS.
Can not be output. By the way, the main CP
U2 performs this failure determination as an initial check.

Further, in the failure judgment of the switching circuit 50, when the main CPU 2 outputs the L signal as the main signal SM to the switching circuit 50, the main return signal RM1 from the switching circuit 50 outputs the H signal (or If the state of the main return signal RM2 is L signal) for 10 mS, the switching circuit 50 determines that a failure has occurred. Also, the main C
The PU 2 transmits a request signal for checking the switching circuit 50 to the sub CPU 4, and causes the switching circuit 50 to output an L signal as the sub signal SS from the sub CPU 4. Then, when the state of the main return signal RM1 from the switching circuit 50 as the H signal (or the main return signal RM2 as the L signal) continues for 10 ms, the main CPU 2 determines that the switching circuit 50 has failed. By the way,
The main CPU 2 also performs these failure determinations as an initial check.

Next, the sub CPU 4 will be described. The sub CPU 4 determines whether control of the electric power steering device by the main CPU 2 is prohibited. The sub CPU 4 monitors the main CPU 2 and monitors itself. Further, when the main CPU 2 or the sub CPU 4 fails, the sub CPU 4 controls the VGS motor 21 by the switching circuit 50 by the backup CPU 3.
To stop all functions.

In the prohibition determination of the control of the main CPU 2, the sub CPU 4 monitors the main drive control signal MEMS or the like from the main CPU 2 to determine whether the EPS motor 20 is abnormally driven or to determine whether the EPS motor 20 is abnormally driven or the steering torque signal TS.
And monitors the relationship between the EPS motor current signal EIMO and the abnormal output of the main CPU 2, and outputs an auxiliary inhibition signal SB to the gate drive circuit 44. The auxiliary inhibition signal SB is an H signal when the control by the main CPU 2 is inhibited, and is an L signal when the control by the main CPU 2 is not inhibited.
Signal.

In monitoring the main CPU 2, the sub C
The PU 4 compares the vehicle speed and the like calculated by the main CPU 2 with the vehicle speed and the like calculated by itself, monitors the main CPU 2, and determines whether the main CPU 2 is normal or has a failure. Then, the sub CPU 4 transmits the main CPU monitoring information to the main CPU 2.

The sub-CPU 4 generates a sub-signal SS by a self-monitoring function using a watchdog timer using the sub-CPU monitoring information from the main CPU 2 and outputs it to the switching circuit 50. Note that the sub signal SS is
The signal is H when the PU 4 is normal, and is L when the sub CPU 4 is out of order.

When the main CPU 2 or the sub CPU 4 fails, the sub CPU 4 outputs the L signal as the sub signal SS to the switching circuit 50 and supplies the backup CPU 3 with VGS.
The control of the motor 21 is switched, and all functions are stopped.

Next, the backup CPU 3 will be described. The backup CPU 3 always controls the VGS motor 2 of the steering angle ratio variable device 15 so that the eccentric amount shifts to the safe side.
1 is generated, a backup drive control signal BVMS for the VGS motor 21 is generated. When the main CPU 2 or the sub CPU 4 fails, the backup CPU 3 controls the VGS motor 21 of the variable steering angle ratio device 15 so that the eccentricity e shifts to the safe side. Further, the backup CPU 3 stops all functions when it fails.

Next, referring to FIG.
The internal configuration of U3 will be described. The backup CPU 3
Mainly, the target eccentricity setting unit 3a, the deviation calculation unit 3b, P
It comprises an ID control unit 3c and a PWM signal generation unit 3d.

The target eccentricity setting section 3a is provided with a ROM (R
There is provided a storage means such as an ead only memory, and the maximum eccentricity is stored as the target eccentricity CE.
Then, the target eccentricity setting section 3a outputs the target eccentricity CE to the eccentricity calculating section 3b. By the way, the steering angle ratio variable device 1
5, the change characteristic of the steering angle ratio of the variable steering angle ratio device 15 becomes the highest dull characteristic, and the steering wheels W and W are changed with respect to the steering of the steering wheel 11 from the neutral position. W slowly follows and steers. Further, the steering wheel 11 can be lightly operated even when the auxiliary steering torque by the EPS motor 20 is not applied.

The deviation calculator 3b has a subtractor or a soft control subtraction function. The target eccentricity CE from the target eccentricity setting unit 3a and the eccentricity signal A from the actual eccentricity input circuit 43 are provided.
E is input, and the deviation ΔE is output to the PID control unit 3c. The deviation calculator 3b calculates the actual eccentricity A from the target eccentricity CE.
E is subtracted to calculate a deviation ΔE (= CE−AE).

The PID control unit 3c receives the deviation ΔE from the deviation calculation unit 3c and inputs the deviation ΔE to the PWM signal generation unit 3d.
A PID control signal PS for E is output. The PID control unit 3c performs P (proportional), I (integral), and D (differential) control on the deviation ΔE, and sets V to make the deviation close to zero.
A PID control signal PS indicating the direction and current value of the current supplied to the GS motor 21 is generated.

The PWM signal generator 3d is provided with a PID controller 3
c, the PID control signal PS from the
Outputs the backup drive control signal BVMS. PW
The M signal generating unit 3d is configured to output the M signal based on the PID control signal PS.
A PWM signal, an ON signal, and an OFF signal corresponding to the direction and current value of the current supplied to the VGS motor 21 are generated. The backup drive control signal BVMS includes a PWM signal, an ON signal, and an OFF signal output to the gates G1 to G4 of the VGS bridge circuit 46. The VGS bridge circuit 4 by the backup drive control signal BVMS
6 is controlled by the main drive control signal MVMS described above.
Since the drive control of the VGS bridge circuit 46 is the same as that of FIG.

The backup CPU 3 is connected to the main CPU 2
Even when the steering angle ratio variable device 15 is controlled by
A backup drive control signal BVMS is generated and output to the switching circuit 50. The backup drive control signal BVMS is transmitted by the switching circuit 50 to the main CPU 2.
Alternatively, the signal is supplied to the VGS bridge circuit 46 only when the sub CPU 4 fails or the electronic control device 40 is hard reset from the outside. The backup CPU 3
Is the backup return signal R from the switching circuit 50.
B1 is the L signal (or the return signal R for backup)
When B2 is an H signal), the main CPU 2 or the sub CP
It can be determined that U4 has failed or that the electronic control unit 40 has been externally hard reset.

The backup CPU 3 is connected to the main CPU 2
Using the backup CPU monitoring information and the like, a self-monitoring function using a watchdog timer determines whether a malfunction or a failure has occurred. If the backup CPU 3 determines that it has failed, it stops all functions.

Next, referring to FIG.
Will be described. The gate drive circuit 44 is provided with an EPS
An EPS gate control signal EMS is output to each of the gates G1 to G4 of the bridge circuit 45. Further, the gate drive circuit 4
4 is the main CPU 2 when the auxiliary prohibition signal SB is an H signal.
Motor 20 for electric power steering system
Prohibit the control of. Therefore, the gate drive circuit 44 includes
The main drive control signal MEMS from the main CPU 2 and the auxiliary prohibition signal SB from the sub CPU 4 are input, and EPS
The gate control signal EMS is output to the EPS bridge circuit 45.

The gate drive circuit 44 has four NOT circuits and four AND circuits. Then, the gate drive circuit 44 inverts and outputs the auxiliary inhibition signal SB to four AND circuits by using four NOT circuits. Further, the gate drive circuit 4
4 are provided with main drive control signals MEMS for the gates G1 to G4 of the EPS bridge circuit 45.
And the inverted output of the NOT circuit are input, and four A
Gates G1 to G of the ND circuit to the EPS bridge circuit 45
4 outputs an EPS gate control signal EMS. The gate drive circuit 44 outputs all the OFF signals as the EPS gate control signal EMS when the auxiliary prohibition signal SB is the H signal, and outputs the off signal when the auxiliary prohibition signal SB is the H signal.
The main drive control signal MEMS is directly output as the EPS gate control signal EMS.

Next, the switching circuit 50 will be described with reference to FIG. The switching circuit 50 switches the control of the variable steering angle ratio device 15 from the main CPU 2 to the backup CPU 3 when the main CPU 2 or the sub CPU 4 fails or when the electronic control device 40 performs a hard reset. Therefore, the switching circuit 50 receives the main drive control signal MVMS and the main signal SM from the main CPU 2 and the sub CPU
4 and the hard drive reset signal SH and the backup drive control signal BVMS from the backup CPU 3 are input to the VGS bridge circuit 46.
The gate control signal VMS is output. For this purpose, the switching circuit 50 includes a failure determination unit 51, a main output determination unit 52, a backup output determination unit 53, and a return signal output unit 5
4 is provided.

The failure judging section 51 judges whether the main CPU 2 and the sub CPU 4 are faulty or normal, and whether the electronic control unit 40 has a hard reset. For this purpose, the failure determination unit 51 includes three AND circuits 51a, 51b, 5
1c and NOT circuits 51d, 51e and 51f. The AND circuit 51a receives the main signal SM and the hard reset signal SH, and calculates the logical product of these two signals as A
Output to the ND circuit 51c. The hard reset signal SH is an H signal at normal times, and an L signal when a hard reset is performed from outside the electronic control unit 40. The AND circuit 51b receives the sub-signal SS and the hard reset signal SH, and calculates the logical product of these two signals as an AND signal.
Output to the D circuit 51c. AND circuit 51c
The signals of the logical product from the circuit 51a and the AND circuit 51b are respectively input, and the logical product of these two signals is converted to the NOT circuit 51.
d and 51e.

The NOT circuit 51d includes an AND circuit 51
The logical product output from c is inverted and output to the main output determination unit 52 and the return signal output unit 54, respectively. NOT circuit 5
1e inverts the logical product output from the AND circuit 51c to the NOT circuit 51f. NOT circuit 51f
The inverted output from the circuit 51e is used as a backup output determination unit 5.
3 and a return signal output unit 54.
Therefore, when the main signal SM, the sub signal SS, and the hard reset signal SH are all H signals, the failure determination unit 5
1 outputs an H signal from the AND circuit 51c,
It is determined that the PU 2 and the sub CPU 4 are normal and there is no hard reset.

Then, the failure judging section 51 receives the main drive control signal MVMS from the main output judging section 52 as V
To output as a GS gate control signal VMS, A
The H signal from the ND circuit 51c is output to the main output determination unit 52 as an L signal by the NOT circuit 51d. Further, the failure determination unit 51 outputs the H signal from the AND circuit 51c to the NOT circuit 51 so that the backup output determination unit 53 stops the output of the backup drive control signal BVMS.
e and 51f output an H signal to the backup output determination unit 53.

On the other hand, at least one of the main signal SM, the sub signal SS and the hard reset signal SH is at L level.
In the case of a signal, the failure determination unit 51 outputs an L signal from the AND circuit 51c, and determines that the main CPU 2 or the sub CPU 4 has failed or has a hard reset. And
The failure determination section 51 outputs the L signal from the AND circuit 51c to the main output determination section 52 as an H signal by the NOT circuit 51d so that the main output determination section 52 stops the output of the main drive control signal MVMS. Further, the failure determination section 51 outputs the AND circuit 51 so that the backup output determination section 53 outputs the backup drive control signal BVMS as it is as the VGS gate control signal VMS.
The L signal from c is output to the L circuits by NOT circuits 51e and 51f.
The signal is output to the backup output determination unit 53 as a signal.

Incidentally, the two NOT circuits 51e and 51
The logic of the signal is returned to the original logic by f. This is to ensure the insulation between the two power supply circuits of the main power supply 5 and the backup power supply 6 included in the electronic control unit 40. This is because the switching elements 51e and 51f are constituted by switching elements such as transistors, and even if one of them is short-circuited, the other is electrically insulated.

The main output determination section 52 determines whether or not to output the main drive control signal MVMS to the VGS bridge circuit 46. For this purpose, the main output determination unit 52
Four NOT circuits 52a, 52b, 52c, 52d and 4
And two AND circuits 52e, 52f, 52g, and 52h. The NOT circuits 52a, 52b, 52c, 52d
A signal from the OT circuit 51d is input, and this signal is
The inverted signals are output to the D circuits 52e, 52f, 52g, and 52h, respectively. The signals from the NOT circuits 52a, 52b, 52c, and 52d and the gates G1 to G4 of the VGS bridge circuit 46 are provided to the AND circuits 52e, 52f, 52g, and 52h.
, And a main drive control signal MVMS for each of them is input, and the logical product of these signals is output. The signals input to the NOT circuits 52a, 52b, 52c, 52d are H
Signal (that is, the main CPU 2 or the sub CP
If U4 fails or has a hard reset), AN
The D circuits 52e, 52f, 52g, 52h all output L signals.

On the other hand, NOT circuits 52a, 52b, 52
When the signals input to c and 52d are L signals (that is, when the main CPU 2 and the sub CPU 4 are normal and there is no hard reset), the AND circuits 52e, 52f,
52g and 52h are input main drive control signals MV
Output MS as it is. Then, the main drive control signal MVMS becomes VGS as the VGS gate control signal VMS.
The signals are input to the gates G1 to G4 of the bridge circuit 46.

The backup output determination section 53 determines whether or not to output the backup drive control signal BVMS to the VGS bridge circuit 46. For this purpose, the backup output determination unit 53 includes four NOT circuits 53a, 53b,
53c, 53d and four AND circuits 53e, 53f, 5
3g, 53h. NOT circuits 53a, 53b, 5
Signals from the NOT circuit 51f are input to 3c and 53d, and the signals are converted to AND circuits 53e, 53f, 53g, and 5d.
The output is inverted at 3h. AND circuits 53e, 53f,
NOT circuits 53a, 53b, 53
c, 53d and a backup drive control signal B for each of the gates G1 to G4 of the VGS bridge circuit 46.
VMS are input, and the logical product of these signals is output. Then, NOT circuits 53a, 53b, 53c, 53
If the signal input to d is an L signal (that is, if the main CPU 2 or the sub CPU 4 has failed or has a hard reset), the AND circuits 53e, 53f, and 53
g and 53h are the inputted backup drive control signals B
The VMS is output as it is. Then, the backup drive control signal BVMS is input to each of the gates G1 to G4 of the VGS bridge circuit 46 as the VGS gate control signal VMS.

On the other hand, NOT circuits 53a, 53b, 53
When the signals input to c and 53d are H signals (that is, when the main CPU 2 and the sub CPU 4 are normal and there is no hard reset), the AND circuits 52e, 52f,
52g and 52h all output the L signal.

The return signal output unit 54 is provided with main return signals RM1 and RM2 for use in failure determination and the like.
And backup return signals RB1 and RB2. Therefore, the return signal output unit 54 includes four NOT circuits 54a, 54b 54c, and 54d.
The NOT circuit 54a inverts and outputs the signal from the NOT circuit 51d to the main CPU 2 as the main return signal RM1. The NOT circuit 54b inverts and outputs the signal from the NOT circuit 51d to the backup CPU 3 as the backup return signal RB1. NOT circuit 54c
Outputs the signal from the NOT circuit 51f to the main CPU 2 as a main return signal RM2. NOT
The circuit 54d uses the signal from the NOT circuit 51f as the backup return signal RB2 and
Is inverted.

Therefore, the switching circuit 50 sets the main signal SM, the sub signal SS, and the hard reset signal all to H level.
In the case of a signal, the main drive control signal MVMS is output to the VGS bridge circuit 46 as the VGS gate control signal VMS. On the other hand, when at least one of the main signal SM, the sub signal SS and the hard reset signal is an L signal, the switching circuit 50 outputs the backup drive control signal BVMS
To the VGS bridge circuit 46 as the VGS gate control signal VMS.

Next, the EPS bridge circuit 45 will be described with reference to FIG. The EPS bridge circuit 45 receives the EPS gate control signal EMS from the gate drive circuit 44, and generates an E based on the EPS gate control signal EMS.
The PS motor voltage EVM is applied to the EPS motor 20,
An EPS motor current EIM is output to the PS motor 20.
The EPS bridge circuit 45 is composed of a bridge circuit composed of switching elements of four power FETs (field effect transistors) 45a, 45b, 45c, and 45d.
A voltage of 2V is supplied. Further, the EPS bridge circuit 45 includes the EPS motor 20 connected in series between the power FET 45a and the power FET 45d, and
b and the power FET 45c are connected in series.

The power FETs 45a and 45b are turned on when a PWM signal or an OFF signal is input to each of the gates G1 and G2, and when the PWM signal is input and the logic level is "1". The power FETs 45c and 45d have respective gates G3 and
An ON signal or an OFF signal is input to G4, and the signal turns on when the ON signal is input. The EPS bridge circuit 45 includes power FETs 45a, 45b, 45c, and 45d.
When an EPS gate control signal EMS is input to each of the gates G1, G2, G3, and G4, the EPS motor voltage EVM is applied to the EPS motor 20 based on the EPS gate control signal EMS. Then, the EPS motor 20 has an EP
The S motor current EIM flows, and the EPS motor 20 drives forward or reverse to generate a torque proportional to the EPS motor current EIM.

Note that the EP applied to the EPS motor 20
The S motor voltage EVM is determined by the duty ratio of the PWM signal. Then, E flowing through the EPS motor 20
PS motor current EIM corresponds to EPS motor voltage EVM. For example, when the duty ratio of the PWM signal is 7 (logical level 1): 3 (logical level 0), 12V × (7
/10)=8.4V becomes the EPS motor voltage EVM,
This means that 8.4 V is continuously applied to the EPS motor 20.

Next, the VGS bridge circuit 46 will be described with reference to FIG. In the VGS bridge circuit 46,
The VGS gate control signal VMS is input from the switching circuit 50, and VGS is controlled based on the VGS gate control signal VMS.
The motor voltage VVM is applied to the VGS motor 21 and VGS
The VGS motor current VIM is output to the motor 21. VG
The S bridge circuit 46 is constituted by a bridge circuit including switching elements of four power FETs (field effect transistors) 46a, 46b, 46c, 46d, and has a 12V
Are supplied. The VGS bridge circuit 46
Has the same configuration and operation as the EPS bridge circuit 45, and a detailed description thereof will be omitted.

In one embodiment of the electronic control unit for a vehicle configured as described above, the main CPU 2 and the sub CPU 4
Is normal, the electronic control unit 40 executes EPS control and VGS control by the main CPU 2. For this purpose, the main CPU 2 sets a target current value based on the steering torque signal TS and the vehicle speed signal VP, and generates a main drive value based on the target current value and the EPS motor current signal EIMO from the EPS motor current sensor 32. The control signal MEMS is output to the gate drive circuit 44. Further, the gate drive circuit 44 outputs an EPS gate control signal EMS to each of the gates G1 to G4 of the EPS bridge circuit 45 based on the auxiliary inhibition signal SB. And EPS
The bridge circuit 45 applies the EPS motor voltage EVM to the EPS motor 20 based on the EPS gate control signal EMS, and supplies the EPS motor current EIM. Then, the rotational driving force of the EPS motor 20 generates an auxiliary steering torque of the electric power steering device, and assists the driver's steering force.

The electronic control unit 40 includes a main CPU
2, a target eccentricity is set based on the vehicle speed signal VP or the like, and the main drive control signal MV generated based on the target eccentricity and the actual eccentricity AE from the actual eccentricity input circuit 43.
Output MS. Further, the switching circuit 50 includes a main CP
Since U2 and sub CPU 4 are normal (ie, both main signal SM and sub signal SS are H signals), main drive control signal MVMS is changed to VGS gate control signal VM.
As S, each gate G1 to G4 of the VGS bridge circuit 46
Output to Then, the VGS bridge circuit 46
The VGS motor voltage VVM is applied to the VGS motor 21 based on the S gate control signal VMS, and the VGS motor current V
Supply IM. Then, the rotation support member 15J is rotated by the rotation driving force of the VGS motor 21, and the eccentric amount e of the variable steering angle ratio device 15 becomes the target eccentric amount CE.
The change characteristic of the steering angle ratio is optimized. The backup CPU 3 always outputs a backup drive control signal BVMS to the switching circuit 50 as a preparation function that can instantaneously exhibit the fail-safe control function of the VGS control.

When the main CPU 2 or the sub CPU 4 fails, the electronic control unit 40 controls the main CPU 2 and the sub CPU
Stop all functions by PU4. Therefore, the control of the electric power steering device is stopped, and the steering force of the driver is not assisted because no auxiliary steering torque is generated. However, the variable steering angle ratio device 15 is controlled by the backup CPU 3 so that the change characteristic of the steering angle ratio shifts to the highest dull side. Therefore, the steering wheel 11 requires a large amount of operation, but has a small operating force. Incidentally, since the main CPU 2 and the sub CPU 4 are communicating with each other, it is possible to recognize that they have failed each other.

That is, when the main CPU 2 fails, the main CPU 2 outputs the L signal as the main signal SM, and when the sub CPU 4 fails, the sub CPU outputs the L signal as the sub signal SS. Then, the switching circuit 50
Performs a failure determination in a failure determination section 51 and outputs a NOT
d outputs an H signal, and NOT circuit 51f outputs an L signal. With this signal, the switching circuit 50 stops the output of the main drive control signal MVMS in the main output determination section 52, outputs the backup drive control signal BVMS as it is in the backup output determination section 53, and outputs the backup drive control signal BVMS. Each gate G of the VGS bridge circuit 46 is used as the VGS gate control signal VMS.
1 to G4.

The backup CPU 3 always has the target eccentricity set to the maximum eccentricity and the actual eccentricity input circuit 4.
3 outputs a backup drive control signal BVMS generated on the basis of the actual eccentricity AE. And VGS
The bridge circuit 46 applies the VGS motor voltage VVM to the VGS motor 21 based on the VGS gate control signal VMS, and supplies the VGS motor current VIM. By the way,
Since the steering angle ratio variable device 15 is shifted to the maximum eccentric amount, V
A large VGS motor current VIM flows through the GS motor 21. Then, the rotation support member 15J is rotated by the rotational driving force of the VGS motor 21, and the eccentric amount of the variable steering angle ratio device 15 becomes the maximum eccentric amount.

In the initial check by the main CPU 2, the main CPU 2 checks whether or not each section in the electronic control device 40 is functioning normally when the electronic control device 40 is started. Here, an initial check of whether the backup CPU 44 and the switching circuit 50 are functioning normally will be described.

First, the main CPU 2 outputs the main signal SM
And outputs the L signal in a pseudo manner, and monitors the VGS motor current signal VIMO from the VGS motor current sensor 33,
It is checked whether the backup CPU 3 and the switching circuit 50 are functioning normally. That is, the main signal S
When M is an L signal, as described above, the switching circuit 50
The backup drive control signal BVMS is output as the VGS gate control signal VMS. Then, the backup CP
In the control of U3, the steering angle ratio variable device 15 is shifted to the maximum eccentric amount, so that a large VGS motor current VIM flows through the VGS motor 21. However, if the switching circuit 50 has not normally switched or the backup CPU 3 has not normally output the backup drive control signal BVMS, the VGS motor current VIM does not flow through the VGS motor 21. Therefore, when the VGS motor current signal VIMO is kept at 1 A or less for 10 mS when the L signal is pseudo-outputted as the main signal SM, the main CPU 2 determines that the VGS motor current VIM is not flowing through the VGS motor 21. ), Backup CPU
3 or the switching circuit 50 determines that a failure has occurred. Then, the main CPU 2 shifts the change characteristic of the steering angle ratio of the variable steering angle ratio device 15 to the highest dull characteristic, and performs assist complement control on the electric power steering device.

Further, the main CPU 2 outputs the main signal S
An L signal is output as M, and the main return signals RM1 and RM2 from the switching circuit 50 are monitored to check whether the switching circuit 50 is functioning normally. That is, when the main signal SM is an L signal, the switching circuit 50 causes the failure determination unit 51 and the return signal output unit 54 to output an L signal as the main return signal RM1 and an H signal as the main return signal RM2. However, if the switching circuit 50 is not functioning properly, the main signal SM
Output the H signal as the main return signal RM1 or the L signal as the main return signal RM2. Therefore, the main CPU 2 outputs the main signal SM
If the state of the main return signal RM1 from the switching circuit 50 as the H signal (or the main return signal RM2 as the L signal) from the switching circuit 50 continues for 10 mS when the L signal is output, the switching circuit 50 is determined to be faulty. And the main C
The PU 2 shifts the change characteristic of the steering angle ratio of the steering angle ratio variable device 15 to the highest dull characteristic, and performs assist complement control for the electric power steering device.

The main CPU 2 outputs a request signal to the sub CPU 4 so as to output the L signal as the sub signal SS, monitors the main return signals RM1 and RM2 from the switching circuit 50, and the switching circuit 50 operates normally. Check to see if it works. That is, the sub signal SS
Is an L signal, the switching circuit 50 operates as in the case where the main signal SM is an L signal. Therefore, when the main CPU 2 outputs a request signal to the sub CPU 4 to output the L signal as the sub signal SS, the main return signal RM1 from the switching circuit 50 becomes the H signal (or the main return signal RM2 becomes the L signal). When the state of (signal) continues for 10 ms, the switching circuit 50 determines that a failure has occurred. The main CPU 2 controls the variable steering angle ratio steering device 1.
While shifting the steering angle ratio characteristics of the
The assist complement control is performed on the electric power steering device.

That is, in the vehicular electronic control device of one embodiment, the EPS control of the electric power steering device is normally performed when the main CPU 2, the backup CPU 3, the sub CPU 4, etc. on the control circuit board 1 are operating normally. VGS control of the variable steering angle ratio steering device is the main CPU
2 is performed. At this time, the main CPU 2
The sub CPU 4 monitors whether the operation of the U4 and the backup CPU 3 is normal, the sub CPU 4 monitors whether the operation of the main CPU 2 is normal, and the backup CPU 3
It is prepared so that the fail-safe control function of the GS control can be immediately exhibited.

Here, when an abnormality occurs in the backup CPU 3, the backup CPU 3 stops its function. At that time, the main CPU 2 detects the abnormality by the monitoring function of the backup CPU 3, executes the assist complement control in which the EPS control is limited to the basic control, and
The fail-safe control of the VGS control is executed. That is, as the assist supplement control, the assist steering torque that increases or decreases only in response to the detection signal of the steering torque sensor 30 is set to the EPS.
Generated by the motor 20. Further, as the fail-safe control of the VGS control, the change characteristic of the steering angle ratio of the steering angle ratio variable device 15 is changed so that the so-called dull feeling is strong and the steering force is light, that is, the change of the input shaft 15A with respect to the output shaft 15B is performed. The rotation of the VGS motor 21 is controlled so that the amount of eccentricity e becomes maximum.

On the other hand, if an abnormality occurs in the sub CPU 4,
The sub CPU 4 stops the mutual monitoring function with the main CPU 2 and sends a signal for causing the backup CPU 3 to execute the fail-safe control of the VGS control. that time,
The main CPU 2 detects the abnormality by the monitoring function of the sub CPU 4 and sends a signal for executing the fail-safe control of the VGS control to the backup CPU 3.

Here, due to heavy rain such as a shower, FIG.
When the control circuit board 1 is flooded with rainwater accumulated on the floor F and the control circuit board 1 is flooded, the main CPU 2 disposed below the control circuit board 1 is flooded before the backup CPU 3. When the main CPU 2 is damaged by water, the main CPU 2 stops the mutual monitoring function with the sub CPU 4 and sends a signal to the backup CPU 3 to execute the fail-safe control of the VGS control. Therefore, the backup CPU 3, which is prepared to immediately exhibit the fail-safe control function of the VGS control,
The VGS motor 21 is controlled so that the change characteristic of the steering angle ratio of the variable steering angle ratio device 15 is a stable change characteristic with a so-called dull feeling, that is, the eccentricity of the input shaft 15A with respect to the output shaft 15B is maximized. Control rotation.

[0094]

As described above, according to the vehicular electronic control device of the present invention, when the control circuit board is flooded due to water in the vehicle interior, the main CPU is flooded before the backup CPU. The CPU can surely exhibit the fail-safe control function in the event of an abnormality of the main CPU before the CPU is wet.

In the vehicle control apparatus of the present invention, if the main CPU has a VGS control function and the backup CPU has a fail-safe control function of the VGS control, the backup CPU is wetted by itself. It is possible to exhibit the fail-safe control function of the VGS control before. For example, as a fail-safe control function of the VGS control, it is possible to change a change characteristic of a steering angle ratio of a turning angle to a steering angle to a stable change characteristic having a so-called dull feeling.

Further, in the vehicle control device of the present invention,
Sub C having a mutual monitoring function with the main CPU
When the PU is disposed below the backup CPU and provided on the control circuit board, when one of the main CPU and the sub CPU is wet, the monitoring function of the other CPU monitors the wet CPU. Accordingly, the backup CPU can exhibit the fail-safe control function before it is flooded. For example, a fail-safe control function of VGS control can be exhibited to change a change characteristic of a steering angle ratio of a turning angle to a steering angle to a stable change characteristic having a so-called dull feeling.

Further, in the vehicle control device according to the present invention, the power source of the backup CPU is connected to the main CPU.
If the power supply of the main CPU is disposed below the backup CPU and its power supply,
Since the main CPU and its power supply are flooded before the backup CPU and its power supply, the backup CPU
Also, the power supply can surely exhibit the fail-safe control function before it is flooded. For example, VG
By exhibiting the fail-safe control function of the S control, it is possible to change the change characteristic of the steering angle ratio of the turning angle to the steering angle to a stable change characteristic with a so-called dull feeling.

[Brief description of the drawings]

FIG. 1 is a layout diagram of a control circuit board of a vehicle electronic control device according to an embodiment of the present invention in a vehicle cabin.

FIG. 2 is an arrangement configuration diagram of a main CPU, a backup CPU, and the like on a control circuit board of the vehicle electronic control device according to one embodiment.

FIG. 3 is an overall configuration diagram of a steering system controlled by a vehicle electronic control device according to one embodiment.

FIG. 4 is a longitudinal sectional view of a variable steering angle ratio device controlled by a vehicle electronic control device according to one embodiment.

FIG. 5 is an exploded perspective view showing a connection structure of an input shaft and an output shaft of the variable steering angle ratio device controlled by the vehicle electronic control device according to the embodiment.

FIG. 6 is a transverse sectional view taken along the line AA of FIG. 4;

FIG. 7 is a graph showing a relationship between a rotation angle of an input shaft and a rotation angle of an output shaft in a variable steering angle ratio device controlled by a vehicle electronic control device according to one embodiment.

FIG. 8 is a block diagram of an electronic control unit that constitutes the vehicle electronic control unit according to one embodiment.

FIG. 9 is an internal block configuration diagram of a backup CPU included in the vehicle electronic control device according to the embodiment.

FIG. 10 is a logic circuit diagram of a switching circuit included in the vehicle electronic control device according to the embodiment.

[Explanation of symbols]

 1: Control circuit board 2: Main CPU 3: Backup CPU 4: Sub CPU 5: Main power supply 6: Backup power supply 10: Steering system 15: Variable steering angle ratio device 20: EPS motor 21: VGS motor 25: Displacement sensor 30: Steering torque sensor 31: Vehicle speed sensor 32: EPS motor current sensor 33: VGS motor current sensor 41: Steering torque input circuit 42: Vehicle speed input circuit 43: Actual eccentricity input circuit 44: Gate drive circuit 50: Switching circuit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B62D 119: 00 B62D 119: 00 (72) Inventor Koji Sasashima 1-4-1 Chuo, Wako-shi, Saitama Stock 3D032 CC35 CC37 DA04 DA15 DA16 DA23 DA64 DC01 DC02 DC04 DD10 DD17 EA01 EB04 EB05 EC23 EC31 3D033 CA03 CA04 CA05 CA16 CA18 CA20 CA21 CA28 CA32

Claims (4)

[Claims] An electronic control unit for a vehicle, wherein a control circuit board having at least a main CPU and a backup CPU is disposed near a floor in a vehicle interior, the electronic control unit having a fail-safe control function when the main CPU is abnormal. An electronic control unit for a vehicle, wherein the backup CPU is disposed above the main CPU. 2. The vehicular electronic control device according to claim 1, wherein the main CPU has a VGS control function, and the backup CPU has a fail-safe control function of the VGS control. 3. The control circuit board according to claim 1, wherein the main CP is
3. The electronic control unit for a vehicle according to claim 1, wherein a sub CPU having a mutual monitoring function with the U is provided below the backup CPU. 4. 4. The power supply of the backup CPU is arranged above the main CPU, and the power supply of the main CPU is arranged below the backup CPU and its power supply. 3. The electronic control device for a vehicle according to claim 1.