JP2001270452A - Control device and variable steering angle ratio steering device - Google Patents

Abstract

(57) [Problem] To improve the efficiency of designing and manufacturing a CPU with a small amount of processing, and not to mistake the installation position when installing a CPU. SOLUTION: As a sub CPU 42 and a backup CPU 43 in a control device 40, CPUs having the same structure
Is used. This CPU includes a sub-program control unit 65 and a backup program control unit 66 with a small processing amount, and further, a determination port 67 is provided. A discrimination voltage for discriminating between the sub CPU 42 and the backup CPU 43 is supplied to the discrimination ports 67 and 67 from the board, and based on the discrimination voltage, which of the sub CPU 42 and the backup CPU 43 is used is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device provided with two CPUs, and the steering of a steering wheel with respect to a suitable steering angle of a steering wheel according to a driving operation situation of a vehicle by a driver using the control device. The present invention relates to a variable steering angle ratio steering device that performs control capable of automatically setting an angle ratio (hereinafter, referred to as “steering angle ratio”).

[0002]

2. Description of the Related Art Conventionally, as a vehicular steering device for assisting a driver's driving, there is known a vehicular steering device which automatically sets a steering angle ratio according to a surrounding environment of a vehicle.

[0003] For example, the present applicant has disclosed in
No. 944 discloses a variable steering angle ratio steering device for a vehicle. The variable steering angle ratio steering device for a vehicle includes a variable steering angle ratio device capable of changing the rotation amount of a steered wheel with respect to a steering wheel, and a control device for controlling the variable steering angle ratio device. Further, the variable steering angle ratio steering device includes an electric motor for varying the steering angle ratio.

Then, the steering angle ratio is automatically set according to the vehicle speed and the like. For example, when running lightly on a mountain road with continuous curves, the steering angle ratio is set to be large. Conversely, when the vehicle travels on a highway or the like at a substantially constant speed, the steering angle ratio is set to be small, and a steering angle ratio suitable for each case is set.

[0005]

In such a control device for a variable steering angle ratio steering device, it is necessary to consider safety and the like when a failure occurs in the variable steering angle ratio steering device.
For this reason, the control device includes a main CP that is normally used.
It is conceivable to provide a sub CPU for mutually detecting a failure between U and the main CPU, and a backup CPU used when a failure occurs in the main CPU or the sub CPU.

However, the sub CPU in the control device
The backup CPU has a very small processing amount as compared with the main CPU. As described above, designing and manufacturing CPUs each having a small processing amount separately may be wasteful. As a result, the cost of the control device itself increases.

Further, a main CPU, a sub CPU, and a backup CPU are provided on a board of the control device, and the voltage of a current supplied to each CPU is specified. At this time, for example, the sub CP
The backup CPU is set at the position where the backup CPU is set, and the sub CPU is set at the position where the backup CPU is set.
Is installed, the sub CPU and the backup C
An appropriate voltage is not applied to the PU. Therefore, the sub C
There is a problem that the PU and the backup CPU do not function properly.

Therefore, an object of the present invention is to design and design a CPU.
In addition to increasing the efficiency of manufacturing, when installing a CPU,
The purpose is to ensure that the installation position is not mistaken.

[0009]

According to a first aspect of the present invention which solves the above problems, a first CPU having a first program written therein and a second CPU having a second program written therein are provided on a substrate. A control device, wherein both the first program and the second program are written as the first CPU and the second CPU, and a determination port for determining the first CPU and the second CPU is provided. A CPU is used, the CPU is mounted on a board, and a discrimination voltage is applied from the board via the discrimination port, and based on the discrimination voltage, the CPU is used by the first CPU and the second CPU.
A control device for determining which of the CPUs is used.

In the invention according to claim 1, a CPU in which both the first program and the second program are written is used as the first CPU in which the first program is written and the second CPU in which the second program is written. ing. For this reason, the trouble of individually designing and manufacturing the CPU in which the program is written can be omitted.

Also, both CPUs are provided with a discrimination port, and a discrimination voltage is applied to both CPUs.
Determine which of the PU and the second CPU is used. For this reason, after the first CPU and the second CPU are installed, the first CP
Automatically determining whether to function as U or the second CPU. Therefore, the first CPU and the second CP
When mounting the U on the board, each CPU may be installed at a corresponding position on the board without discriminating between them, so that there is no mistake in mounting the first CPU and the second CPU. It should be noted that the term "determination voltage is applied" in the present invention means that a voltage of 0 V is applied, in other words, it includes the state of being grounded.

According to a second aspect of the present invention, a variable steering angle ratio device capable of changing a ratio of a steering angle of the steering wheel to the steering wheel is provided in a steering system from the steering wheel to the steering wheel. In a variable steering angle ratio steering device provided with a control device for controlling an angle ratio device, the control device includes: a main CPU that is normally used; a sub CPU that monitors failures between the main CPU and the main CPU; Backup CPU used when at least one of the main CPU and the sub CPU fails
And both the program corresponding to the sub CPU and the program corresponding to the backup CPU are written as the sub CPU and the backup CPU, and the sub CPU and the backup CPU are determined. A CPU provided with a discrimination port is provided on the board, and a discrimination voltage is given from the board via the discrimination port.
A variable steering angle ratio steering device, wherein a PU is determined as one of the sub CPU and the backup CPU.

In the invention according to claim 2, the sub-CP
Since U and the backup CPU have programs for the sub CPU and the backup CPU, respectively, it is possible to save the trouble of separately designing and manufacturing the sub CPU and the backup CPU. In addition, since the sub CPU and the backup CPU have a smaller processing amount than the main CPU, unnecessary programs not used in each CPU can be reduced. Further, a voltage of, for example, 0 V is applied to the sub CPU via the determination port, and a voltage of 5 V is applied to the backup CPU via the determination port. Therefore, there is no mistake when attaching the sub CPU and the backup CPU.

[0014]

Embodiments of the present invention will be specifically described below with reference to the drawings. The present invention relates to a control device and a variable steering angle ratio steering device. First, the overall configuration of the variable steering angle ratio steering device will be described. FIG. 1 is an overall configuration diagram of a variable steering angle ratio steering device according to the present invention. A variable steering angle ratio steering device 1 according to the present invention includes a variable steering angle ratio device 10 provided in a steering system S from a steering wheel 2 as a steering wheel to steered wheels W, W, and a variable steering angle ratio based on a vehicle speed. Control device 4 for controlling device 10
0 is provided.

In the steering system S, a steering shaft 3 provided integrally with the steering wheel 2 includes:
It is connected to the input shaft of the variable steering angle ratio device 10 via a connection shaft 4 having universal joints 4A and 4B. The variable steering angle ratio device 10 is capable of continuously changing the ratio β / α of the rotation angle β of the output shaft to the rotation angle α of the input shaft. The output shaft of the variable steering angle ratio device 10 is provided with a pinion 5. By meshing the pinion 5 with the rack teeth of the rack shaft 6, the rotational movement of the output shaft is changed by the linear movement (L ), And the linear motion of the rack shaft 6 is converted into the steering motion (T) of the steered wheels W, W via the tie rods 7, 7 and the knuckle arm.

On the side of the rack shaft 6, a motor (hereinafter, referred to as "EPS motor") 8 for an electric power steering device (hereinafter, referred to as "EPS") for generating an auxiliary steering torque is provided. And are arranged coaxially. Then, the rotation of the EPS motor 8 is converted into thrust through a ball screw mechanism 9 provided coaxially with the rack shaft 6, and this thrust is applied to the rack ball screw shaft 9A.

Next, the structure of a specific example of the variable steering angle ratio device 10 according to this embodiment will be described with reference to FIGS. As shown in FIG. 2, the input shaft 11 is rotatably supported via a ball bearing 15 at an eccentric position of a support member 14 rotatably supported by an upper casing 13 a via a ball bearing 12. . At the end of the input shaft 11 protruding into the lower casing 13b, a coupling 16 for transmitting a rotational force to the output shaft 17 is integrally formed. The input shaft 11 is connected to the connection shaft 4 (see FIG. 1), and rotates through the connection shaft 4 when the driver steers the steering wheel 2.

The output shaft 17 has a pair of ball bearings 18.
It is rotatably supported by the lower casing 13b via a and 18b. A pinion 5 meshing with the rack teeth 6a of the rack shaft 6 is formed integrally with a lower portion of the output shaft 17. The end of the output shaft 17 protrudes into the lower casing 13b, and the output shaft 17 at the end of the output shaft 17 is formed.
An intermediate shaft 19 protrudes at a position eccentric from the center of the shaft. The intermediate shaft 19 and the coupling 16 formed integrally with the input shaft 11 are connected to each other via a slider 21 having a flat needle bearing 20 interposed therebetween and a tapered roller bearing 22. Further, a seal member 35 having a flexible tubular portion is provided between the input shaft 11 and the upper casing 13a. The seal member 35 maintains the airtightness of the variable steering angle ratio device 10.

As shown in FIG. 3, a groove 23 having a trapezoidal cross section is formed on the lower surface of the coupling 16 so as to expand and open downward. A slider 21 having a pair of flat needle bearings 20 interposed in the groove 23 is provided in the groove 2.
3 are slidably engaged with each other. An intermediate shaft 19 is engaged with the center of the lower surface of the slider 21 via a tapered roller bearing 22 so as to be relatively rotatable.

As shown in FIG. 2, the lower casing 13b
, An adjusting screw 24 that comes into contact with the outer race of the ball bearing 18b that supports the lower end of the output shaft 17 is screwed. By properly tightening the adjusting screw 24, the pinion 5 is pressed in the axial direction, and an appropriate preload is applied between the input shaft 11 and the output shaft 17 via the coupling 16. In this way, it is possible to improve the connection rigidity by removing the play of the coupling 16.

As shown in FIG. 4, a fan-shaped partial worm wheel 25 is provided on a part of the outer peripheral portion of the support member 14. A worm 28 driven by a motor 27 which is an electric motor is engaged with the partial worm wheel 25 via a worm reduction mechanism 26. And
By the rotational driving force of the motor 27, the support member 14 can be rotated with respect to the upper casing 13a over a predetermined angular range.

The worm 28 is supported by the upper casing 13a via a backlash removing member 29 using an eccentric cam. The hexagonal wrench is engaged with the hexagonal hole 30 formed at the end of the backlash removing member 29, and the hexagonal wrench is rotated with respect to the upper casing 13a, so that the shaft center moves. The engagement with the partial worm wheel 25 is changed. The worm 28 and the worm reduction mechanism 26 are connected via an Oldham coupling 31 in order to allow the axis of the worm 28 to move.

Further, a displacement sensor 33, which is a steering angle ratio sensor of the present invention, comprising a differential transformer or the like engaged with a pin 32 protruding from the upper surface of the support member 14 is attached to the upper casing 13a. . This displacement sensor 33
Detects the amount of displacement of the support member 14. The displacement sensor 33 controls the detected rotation amount of the support member 14, that is, the eccentricity signal (corresponding to the "steering angle ratio signal" of the present invention) 33a of the input shaft 11 supported by the support member 14. 40. In the present embodiment, in the variable steering angle ratio steering device 1, the steering angle ratio characteristic changes according to the amount of eccentricity, and the steering angle ratio continuously changes according to the steering angle of the steering wheel based on the steering angle ratio characteristic. To the optimal value for
That is, in the present embodiment, the steering angle ratio changes according to the amount of eccentricity. Therefore, in the present embodiment, instead of directly detecting the steering angle ratio, the displacement sensor 3 uses the actual eccentric amount corresponding to the actual steering angle ratio.
3 is detected.

The control device 40 includes a target eccentric amount (corresponding to the target steering angle ratio) determined based on the vehicle speed signal Va from the vehicle speed sensor VS and an actual eccentric amount detected by the displacement sensor 33 (corresponding to the actual steering angle ratio). The rotational drive of the motor 27 is controlled by feedback control so as to match 33) (see FIG. 7). The control device 40 will be described later in detail.

The vehicle speed sensor VS is provided in a speedometer (not shown) and detects the speed of the vehicle. Then, the vehicle speed sensor VS transmits to the control device 40 a vehicle speed signal Va of an analog electric signal corresponding to the detected vehicle speed. In addition,
The vehicle speed sensor VS may be a dedicated sensor for the variable steering angle ratio steering device 1 or a sensor shared with another system.

Next, the operation principle of the variable steering angle ratio device will be described. FIG. 5 is an explanatory diagram showing the operation principle of the variable steering angle ratio device, and FIG. 6 is an input / output angle characteristic diagram showing the steering angle ratio characteristics of the variable steering angle ratio device.

As shown in FIG. 5, A is the center of rotation of the input shaft 11, B is the center of rotation of the output shaft 17, and C is the point of action of the intermediate shaft 19. The dimension between BC is b, the amount of eccentricity between the input shaft 11 and the output shaft 17 (dimension between AB) is a, the rotation angle of the input shaft 11 (steering angle) is α, and the rotation angle of the output shaft 17 is α. (Pinion rotation angle) is β. At this time, since b · sin β = (b · cos β−a) tan α, α = tan ⁻¹ (b · sin β / (b · cos β−a)).

When the driver rotates the input shaft 11 by operating the steering wheel 2, the intermediate shaft 1
The crank 9 rotates around the axis of the output shaft 17 by engaging the coupling 16 of the input shaft 11 with the slider 21. For example, as shown in FIG. 5, when the rotation angle α1 of the input shaft 11 is 90 degrees, the rotation angle β1 of the output shaft 17 is as shown in FIG.

Here, when the support member 14 is rotated, the eccentric cam action of the support member 14 changes the axis of the input shaft 11 in the range indicated by reference numerals A0 to A2 in FIGS. When the amount of eccentricity a between the input and output shafts is appropriately determined by changing the axis of the input shaft 11 and the axes of the input shaft 11 and the output shaft 17 are mutually eccentric, the input shaft 11 and the output shaft 17 The rotation angles do not match. In addition, the angle change of the output shaft 17 when the input shaft 11 is rotated by equal angles gradually increases (see the solid lines a1 and a2 in FIG. 6).

When the eccentricity a of the axis between the input shaft 11 and the output shaft 17 is continuously changed in the range of a2 to a0 (a2>a1> a0 = 0), the rotation angle of the input shaft 11 is obtained. , The ratio of the rotation angle of the output shaft 17 to the output shaft 17, that is, the practical steering angle ratio can be continuously changed. Now, if the amount of eccentricity a between the input and output axes is increased, the rate of change of the output angle β with respect to the input angle α gradually increases, and if the amount of eccentricity a between the input and output axes is set to 0, the dashed line (a0 ), The input angle α is equal to the output angle β.

If this change in the steering angle ratio is controlled to, for example, the a0 side in a low-speed running range and the a2 side in a high-speed running range, the rack stroke with respect to the steering angle α of the steering wheel is reduced in the low-speed running range. By setting the value larger than that of the device, more sensitive (quick) characteristics can be realized.
Further, in the high-speed running range, the rack stroke with respect to the steering angle α of the steering wheel is set smaller than that of the conventional steering device, so that a more insensitive (dull) characteristic can be realized. Therefore, the relationship between the practical steering wheel angle and the traveling speed is
Flat characteristics can be obtained.

Next, the control device 40 will be described with reference to FIG. As shown in FIG. 7, the control device 40
A main CPU 41 used during normal times and a main CPU 4
1 and a sub CPU 42 for mutually detecting a failure with the main CPU 41 or the sub CPU 42.
Backup CPU 43 used when 42 fails
have. These main CPU 41 and sub CPU 4
2 and the backup CPU 43 are respectively provided with the switching circuit 4
4 is connected.

The switching circuit 44 includes the motor driving circuit 4
5 and has a changeover switch (not shown), and determines which of the motor drive signal 41a output from the main CPU 41 and the motor drive signal 43a output from the backup CPU 43 is output to the motor drive circuit 45. Switching. The motor drive circuit 45
A bridge circuit composed of four FET switching elements is connected to a battery power supply (not shown), and supplies a current to the motor 27 based on a signal from the switching circuit 44 to drive the motor 27. is there.

Main CPU 41 and sub CPU 42
Is a gate drive circuit 4 for driving the EPS motor 8
6 is connected to the EPS motor drive circuit 47. The EPS motor drive circuit 47 is formed of a bridge circuit including four FET switching elements, is connected to a battery (not shown), and supplies a current to the EPS motor 8 based on an EPS drive signal 41b from the main CPU 41. Then, the EPS motor 8 is driven.
Further, between the EPS motor drive circuit 47 and the EPS motor 8, a motor current detecting means 71 for detecting a current supplied to the EPS motor 8 is provided. The current of the EPS motor 8 detected by the motor current detecting means 71 is output to the main CPU 41 and used for feedback control.

Further, the control device 40 is provided with an actual steering angle ratio input circuit 48. The actual steering angle ratio input circuit 48 outputs the actual eccentricity of the input shaft 11 (FIG. 2) detected by the displacement sensor 33 to the main CPU 41, the sub CPU 42, and the backup CPU 43. On the other hand,
The control device 40 includes a steering torque input circuit 49 and a vehicle speed input circuit 50. The steering torque input circuit 49
The steering torque signal Ta from the steering torque sensor TS is output to the main CPU 41 and the sub CPU 42. The vehicle speed input circuit 50 outputs a vehicle speed signal Va from the vehicle speed sensor VS to the main CPU 41, the sub CPU 42, and the backup CPU 43, respectively.

The main CPU 41, as shown in FIG.
In order to control the variable steering angle ratio device 10, a target eccentricity determination unit 51, a deviation calculation unit 52, a PID control unit 53, a PWM
A signal generator 54 and a gate drive circuit 55 are provided. In order to perform EPS control, the target current setting unit 5
6, a deviation calculation unit 57, a PID control unit 58, and a PWM signal generation unit 59. Further, a sub CPU mutual monitoring unit 6 for mutually detecting a failure with the sub CPU 42.
0 and a backup CPU failure detection unit 61 for detecting a failure of the backup CPU 43.

First, the control of the variable steering angle ratio device 10 will be described. The target eccentricity determining unit 51 includes storage means such as a ROM, and a vehicle speed signal Va and a target eccentricity set in advance based on experimental values or design values. The data (conversion table) corresponding to the quantity is stored. Then, the target eccentricity determination unit 51 reads the corresponding target eccentricity using the vehicle speed signal Va as an address, and outputs the target eccentricity signal 51a to the deviation calculating unit 52. Here, the target eccentric amount is associated with the vehicle speed signal Va at a low speed where the road surface reaction force is large, and at a high speed in order to secure stability during traveling, a large value is set. Corresponding. The vehicle speed signal Va input to the target eccentricity determination unit 51 is obtained by converting the vehicle speed signal Va input from the vehicle speed sensor VS via an FV converter (not shown) from an analog signal to a digital signal.

The deviation calculator 52 calculates the target eccentricity signal 51a.
A deviation between the eccentricity signal 33a indicating the actual eccentricity (corresponding to the actual steering angle ratio) detected by the displacement sensor 33 is obtained, and a deviation signal 52a is output. The eccentricity signal 33a is output to the deviation calculator 52 via the actual steering angle ratio input circuit 48. P
The ID control unit 53 performs processing such as proportionality, integration, and differentiation on the deviation signal 52a, and generates a drive control signal 53a indicating the direction and the current value of the current supplied to the motor 27 to reduce the deviation to zero. And output.

The PWM signal generation section 54 outputs the drive control signal 5
3A for PWM operation of motor 27 based on PWM
An M (pulse width modulation) signal 54 a is output to the gate drive circuit 55. The gate drive circuit 55 outputs to the switching circuit 44 a motor drive signal 55a for driving the gate of each FET of the motor drive circuit 45 based on the PWM signal 54a to switch the FETs.

Next, the steps of the EPS control will be described.
The target current setting section 56 includes storage means such as a ROM, and stores data (conversion table) corresponding to the steering torque signal Ta set in advance based on experimental values or design values and the target eccentricity. Then, the target current setting unit 56
Reads the corresponding target current value using the steering torque signal Ta as an address and calculates the target current signal 56a
7 is output.

The deviation calculator 57 calculates the deviation between the target current signal 56a and the current signal 71a supplied to the EPS motor 8 by the motor current detecting means 71, and calculates the deviation signal 5
7a is output to the PID control unit 58. PID control unit 58
Is a drive control signal 58 indicating the direction and current value of the current supplied to the EPS motor 8 in order to subject the deviation signal 57a to processing such as proportionality, integration, and differentiation, and to make the deviation close to zero.
a is generated and output to the PWM signal generation unit 59.

The PWM signal generation section 59 outputs the drive control signal 5
A PWM (pulse width modulation) signal 59a for performing PWM operation of the EPS motor 8 based on the
6 is output. The gate drive circuit 46 outputs the PWM signal 59
A motor drive signal 46a for driving the gate of each FET of the EPS motor drive circuit 47 based on a to drive the FETs for switching is output to the EPS motor drive circuit 47.

In addition, in the main CPU 41, the sub CP
The U mutual monitoring unit 60 mutually detects a failure with the sub CPU 42. Also, backup CPU
The failure detection unit 61 detects a failure of the backup CPU 43. Thus, in the main CPU 41,
A great deal of processing has been done.

As the sub CPU 42 and the backup CPU 43, CPUs having the same structure are used.
Each has a sub-program control unit 65, a backup program control unit 66, and a determination port 67. The “program corresponding to the sub CPU” of the present invention is written in the subprogram control unit 65, and the “program corresponding to the backup CPU” of the present invention is written in the backup program control unit 66. .

The sub-program control section 65 in the sub-CPU 42 exchanges the failure detection signal 42a with the sub-CPU mutual monitoring section 60 in the main CPU 41 to mutually detect failures. And the main CP
When a failure is detected in U41, a failure signal 42b is output to the switching circuit 44. In the switching circuit 44, the failure signal 4
In response to 2b, the output of the motor drive signal 41a output to the motor drive circuit 45 is stopped. Instead, it outputs a motor drive signal 43 a of the backup CPU 43 to the motor drive circuit 45. The sub CPU 42
In, the backup program control unit 66 does not perform any work.

On the other hand, in the backup program control section 66 of the backup CPU 43, the main CPU 4
When at least one of the sub CPU 1 and the sub CPU 42 fails, a motor drive signal 43 a for driving the motor 27 is generated and output to the switching circuit 44. At normal times, that is, when the main CPU 41 and the sub CPU 42 are functioning normally, the motor drive signal 43 a generated by the backup CPU 43
Is not output to When a failure occurs in at least one of the main CPU 41 and the sub CPU 42, the switching circuit 44 is switched, and the backup C is replaced with the motor drive signal 41a from the main CPU 41.
The motor drive signal 43 a from the PU 43 is output to the motor drive circuit 45. The backup CPU 43 is used when a failure occurs in the main CPU 41. When at least one of the main CPU 41 and the sub CPU 42 fails, the control of the variable steering angle ratio device 10 by the main CPU 41 becomes impossible. . Accordingly, the backup program control unit 66 in the backup CPU 43 generates the motor drive signal 43a for shifting the variable steering angle ratio device 10 to the dull side (the maximum eccentric amount side) from the viewpoint of fail-safe, and
4 is output. In generating the motor drive signal 43a, feedback control is performed using the eccentricity signal 33a output from the actual steering angle ratio input circuit 48.
In the backup CPU 43, the sub-program control unit 65 does not perform any operation.

As described above, the processing amounts of the sub CPU 42 and the backup CPU 43 are small.
Therefore, these are manufactured as CPUs having the same structure,
Even if a program not used for processing is written in each of them, it is not a big waste.

Further, a discrimination voltage is applied to the discrimination ports 67, 67 of the sub CPU 42 and the backup CPU 43 from a board (not shown). The determination voltage applied from the board determines which of the sub CPU 42 and the backup CPU 43 is used. Now, a voltage of 0 V is applied to the determination port 67 in the sub CPU 42, in other words, the ground is provided, and a voltage of 5 V is applied to the determination port 67 in the backup CPU 43. That is, CP
When U is installed, a voltage of 0 V is automatically applied to the determination port 67 of the CPU installed at the position where the sub CPU 42 is to be installed. On the other hand, the determination port 67 of the CPU installed at the position where the backup CPU 43 is to be installed includes:
A voltage of 5V is automatically applied.

The discrimination processing procedure in each of these CPUs will be described with reference to the flowchart shown in FIG. 9. The CPU is installed at a predetermined position and the processing is started (S1). When the process is started, a determination voltage applied to the determination port 67 is detected (S2). As a result, if the discrimination voltage is 0 V, it is used as the sub CPU 42, and the subprogram is executed (S3). On the other hand, if the discrimination voltage is 5 V, it is used as the backup CPU 43, and the backup program is executed (S4). After the subprogram is started or the backup program is executed, it is determined whether or not the control or the like has been completed (S5). As a result, if the control or the like has not been completed, the flow returns to step S2 to detect the determination voltage applied to the determination port 67. On the other hand, if the control or the like has been completed, the determination process ends (S6). In this way, just installing the same CPU at each position,
Automatically the sub CPU 42 and backup CPU 43
Is determined, the sub CPU 42 and the backup C
There will be no mistake in attaching the PU 43. In addition, since the same CPU is manufactured, it is possible to prevent a mistake in making the sub CPU 42 and the backup CPU 43 at the time of manufacturing, a difference in writing a program, and the like.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and a CPU having a program with a small processing amount can be used for other control devices. The present invention can be applied to any control device having two or more control devices. Also, the sub CPU
Although the CPU used for the backup CPU has the same structure, the CPU may not have the same structure as long as it has both the sub-program control unit and the backup program control unit. Furthermore, if there is a common routine between the subprogram and the backup program,
This can be written in one program and shared by both. Even when a program having many such common routines is written, it is effective to use a CPU having the same structure. On the other hand, the sub CPU and the backup CPU may have another program control unit other than the sub program control unit and the backup program control unit.

[0051]

As described above, according to the first aspect of the present invention, it is possible to save the trouble of designing and manufacturing two CPUs individually, thereby preventing an increase in cost. Moreover, there is no mistake in attaching these two CPUs. In addition, it is possible to prevent a mistake in making a CPU, a mistake in writing a program, and the like.

Further, according to the second aspect of the present invention, in the variable steering angle ratio steering device having the main CPU, the sub CPU, and the backup CPU, it is not necessary to separately design and manufacture the sub CPU and the backup CPU. Also, there is no mistake when attaching the sub CPU and the backup CPU.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a variable steering angle ratio steering device according to the present embodiment.

FIG. 2 is a front sectional view of the variable steering angle ratio device according to the embodiment.

FIG. 3 is an exploded perspective view of a shaft portion of the variable steering angle ratio device according to the present embodiment.

FIG. 4 is a sectional view taken along line AA of FIG. 2;

FIG. 5 is an explanatory diagram illustrating an operation principle of the variable steering angle ratio steering device according to the present embodiment.

FIG. 6 is an input / output angle characteristic diagram showing a steering angle ratio characteristic of the variable steering angle ratio steering device according to the present embodiment.

FIG. 7 is a block diagram of a control device of the variable steering angle ratio steering device according to the present embodiment.

FIG. 8 is a block diagram showing a configuration around a main CPU of the variable steering angle ratio steering device according to the present embodiment.

FIG. 9 is a flowchart illustrating a determination processing procedure in a sub CPU and a backup CPU;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Variable steering angle ratio steering device 2 Steering wheel (handle) 10 Variable steering angle ratio device 40 Control device 41 Main CPU 42 Sub CPU (1st CPU) 43 Backup CPU (2nd CPU) 65 Subprogram control unit (1st program) 66 Backup program control unit (second program) 67 Discrimination port W Steering wheel

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideki Watanabe 2021-8, Hozoji Temple, Takanezawa-cho, Shioya-gun, Tochigi Pref. F-term in Keihin Tochigi Development Center (reference) 3D032 CC37 CC48 DA04 DA15 DA16 DA23 DA64 DD10 DD17 EA01 EB05 EC23 GG01 3D033 CA03 CA13 CA16 CA20 CA21 CA28 CA31 JC19

Claims (2)

[Claims] 1. A first CP in which a first program is written
U, and a control device in which a second CPU in which a second program is written is installed on a substrate, wherein both the first program and the second program are written as the first CPU and the second CPU, A CPU provided with a discrimination port for discriminating between the first CPU and the second CPU is used. The CPU is mounted on a board, and a discrimination voltage is applied from the board through the discrimination port. Based on the first CPU and the second CP
A control device for determining which of U is used. 2. A steering system from a steering wheel to a steered wheel is provided with a variable steering angle ratio device capable of changing a steering angle ratio of the steered wheel to the steering wheel, and a control device for controlling the variable steering angle ratio device. In the variable steering angle ratio steering device provided with: a control device, the control device includes: a main CPU that is normally used; and a sub-CP that mutually monitors a failure between the main CPU and the main CPU.
U, and a backup CPU that is used when at least one of the main CPU and the sub CPU fails. As the sub CPU and the backup CPU,
A CP in which both a program corresponding to the sub CPU and a program corresponding to the backup CPU are written, and a determination port for determining the sub CPU and the backup CPU is provided.
U is used, and the CPU is mounted on a board, and a discrimination voltage is given from the board through the discrimination port. Based on the discrimination voltage, the CPU is used as either the sub CPU or the backup CPU. A variable steering angle ratio steering device for determining whether or not to be used.