JP2005032261A - Electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device that improves the efficiency of designing and manufacturing a CPU with a small amount of processing, and prevents the mistake in installing the CPU when installing the CPU.
A CPU having the same structure is used as a sub CPU and a backup CPU 43 in a control device 40. The CPU includes a subprogram control unit 65 and a backup program control unit 66 with a small processing amount, and further includes a determination port 67. From the board, a discrimination voltage for discriminating between the sub CPU 42 and the backup CPU 43 is given to the discrimination ports 67 and 67, and it is determined which of the sub CPU 42 and the backup CPU 43 is used based on this discrimination voltage.
[Selection] Figure 7

Description

  The present invention relates to an electronic device including a plurality of CPUs.

  2. Description of the Related Art Conventionally, as a vehicle steering device that assists driving of a driver, a variable steering angle ratio steering device that automatically sets a steering angle ratio corresponding to the surrounding environment of the vehicle (see, for example, Patent Document 1) is known. Yes. This variable rudder angle ratio steering device has a variable rudder angle ratio device capable of changing the amount of rotation of the steered wheels relative to the steering wheel, and also has a control device for controlling the variable rudder angle ratio device. Further, the variable steering angle ratio steering apparatus includes an electric motor for changing the steering angle ratio.

Then, the steering angle ratio is automatically set according to the vehicle speed and the like. For example, when lightly traveling on a mountain road with continuous curves, the steering angle ratio is increased. Conversely, when traveling 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.
Japanese Patent Laid-Open No. 11-78944 (paragraphs 0011 and 0012, FIG. 1)

  In the control device in such a variable steering angle ratio steering apparatus, it is necessary to consider safety in the event of a failure in the variable steering angle ratio steering apparatus. For this reason, the control device includes a main CPU that is normally used, a sub CPU that performs mutual fault detection with the main CPU, and a backup CPU that is used when a failure occurs in the main CPU or the sub CPU. It is conceivable to use an electronic device provided with

  However, when such an electronic device is used as a control device, the processing amount of the sub CPU and backup CPU is very small compared to the main CPU. In this way, designing and manufacturing CPUs with a small amount of processing separately may cause waste. As a result, the cost of the electronic device itself is increased.

  Further, a main CPU, a sub CPU, and a backup CPU are installed on the board of the electronic device, and the voltage of the current supplied to each CPU is defined. At this time, for example, if the backup CPU is installed at the position where the sub CPU is installed, and the sub CPU is installed at the position where the backup CPU is installed, an appropriate voltage is not applied to the sub CPU and the backup CPU. For this reason, there is a problem that the sub CPU and the backup CPU do not function normally.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to improve the efficiency of CPU design and manufacture, and to prevent the installation position from being mistaken when the CPU is installed. .

The present invention was devised to achieve the above-mentioned object, and the invention according to claim 1 of the present invention that has solved the above-mentioned problems comprises a substrate on which a first CPU and a second CPU are mounted, An electronic device that performs processing by a first program written in a first CPU and processing by a second program written in the second CPU,
The board is configured to give different discrimination voltages to positions where the first CPU and the second CPU are installed,
The first CPU and the second CPU are the same CPU having a discrimination port in which both the first program and the second program are written and used for inputting the discrimination voltage, and An electronic device is characterized in that it is determined which one of the first CPU and the second CPU is used based on a discrimination voltage input from a substrate through the discrimination port.

  In the first aspect of the present invention, 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. For this reason, the trouble of individually designing and manufacturing the CPU in which the program is written can be omitted.

  In addition, both CPUs are provided with a discrimination port, and a discrimination voltage is given to both the CPUs. Based on the discrimination voltage, it is determined whether the both CPUs are used as the first CPU or the second CPU. decide. For this reason, after the first CPU and the second CPU are installed, whether to function as the first CPU or the second CPU is automatically determined according to the discrimination voltage given from the substrate. Therefore, when attaching the first CPU and the second CPU to the board, it is only necessary to install each CPU at a corresponding position on the board without discriminating them. Therefore, it is possible to make a mistake when attaching the first CPU and the second CPU. Disappear. In the present invention, “the determination voltage is given” is given a voltage of 0 V, in other words, includes a grounded state.

  According to the first aspect of the present invention, the trouble of designing and manufacturing the two CPUs individually can be omitted, thereby preventing an increase in cost. Moreover, there is no mistake when attaching these two CPUs. In addition, it is possible to prevent mistakes in making the CPU and writing mistakes in the program.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. The present invention relates to an electronic apparatus. First, the overall configuration of the variable steering angle ratio steering apparatus will be described. FIG. 1 is an overall configuration diagram of a variable steering angle ratio steering apparatus according to an embodiment of the present invention. A variable steering angle ratio steering apparatus 1 according to an embodiment includes a variable steering angle ratio apparatus 10 provided in a steering system S from a steering wheel 2 that is a steering wheel to steering wheels W and W, and a variable steering angle based on a vehicle speed. A control device 40 for controlling the ratio device 10 is provided.

  In the steering system S, a steering shaft 3 provided integrally with the steering wheel 2 is connected to an input shaft of the variable steering angle ratio device 10 via a connecting shaft 4 having universal joints 4A and 4B. The variable steering angle ratio device 10 uses a device that can continuously vary the ratio β / α of the rotation angle β of the output shaft to the rotation angle α of the input shaft. A pinion 5 is provided on the output shaft of the variable rudder angle ratio device 10, and by rotating the pinion 5 and the rack teeth of the rack shaft 6, the rotational motion of the output shaft is converted into the linear motion (L ) To convert the linear motion of the rack shaft 6 into the steered motion (T) of the steered wheels W and W via the tie rods 7 and 7 and the knuckle arm.

  Also, on the side of the rack shaft 6, an electric motor (hereinafter referred to as “EPS motor”) 8 for generating an auxiliary steering torque (hereinafter referred to as “EPS”) 8 is coaxial with the rack shaft 6. It is arranged. 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, with reference to FIG. 2 thru | or FIG. 4, the structure of the example of the variable steering angle ratio apparatus 10 which concerns on this embodiment is demonstrated. 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 that is rotatably supported by the upper casing 13 a via a ball bearing 12. . A coupling 16 that transmits a rotational force to the output shaft 17 is integrally formed at the end of the input shaft 11 that has entered the lower casing 13b. The input shaft 11 is connected to the connecting shaft 4 (see FIG. 1), and rotates through the connecting shaft 4 when the driver steers the steering wheel 2.

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

  As shown in FIG. 3, a groove 23 having a trapezoidal cross section is formed in the lower surface of the coupling 16 so that the lower side is widened and opened. A slider 21 having a pair of flat needle bearings 20 is engaged with the groove 23 so as to slide on the inclined surfaces facing each other. Further, an intermediate shaft 19 is engaged with the center portion of the lower surface of the slider 21 so as to be relatively rotatable via a tapered roller bearing 22.

  As shown in FIG. 2, the lower casing 13 b is screwed with an adjusting screw 24 that comes into contact with the outer race of the ball bearing 18 b that supports the lower end of the output shaft 17. By appropriately tightening the adjustment 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, the coupling rigidity can be improved by removing the backlash 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. The partial worm wheel 25 meshes with a worm 28 driven by a motor 27 which is an electric motor via a worm reduction mechanism 26. The rotational driving force of the motor 27 allows the support member 14 to 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. A hexagonal bar wrench is engaged with the hexagonal hole 30 formed at the end of the backlash removing member 29, and the hexagonal bar wrench is rotated with respect to the upper casing 13a. The meshing with the partial warm wheel 25 is changed. In addition, the worm 28 and the worm speed reduction mechanism 26 are connected via an Oldham coupling 31 to allow movement of the axis of the worm 28.

  Further, a displacement sensor 33, which is a steering angle ratio sensor according to the present invention including a differential transformer that engages with a pin 32 protruding from the upper surface of the support member 14, is attached to the upper casing 13a. The displacement sensor 33 detects the amount of displacement of the support member 14. Then, the displacement sensor 33 controls the detected rotation amount of the support member 14, that is, the eccentric amount signal (corresponding to the “steering angle ratio signal” of the present invention) 33 a of the input shaft 11 supported by the support member 14. 40 is output. In this embodiment, the variable rudder angle ratio steering apparatus 1 changes the rudder angle ratio characteristic according to the amount of eccentricity, and the rudder angle ratio continuously varies according to the steering angle of the steering wheel based on this rudder angle ratio characteristic. Variable to the optimum value for. That is, in the present embodiment, the steering angle ratio changes according to the amount of eccentricity. Therefore, in the present embodiment, the steering angle ratio is not directly detected, but the actual eccentric amount corresponding to the actual steering angle ratio is detected by the displacement sensor 33.

  The control device 40 has 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 (corresponding to the actual steering angle ratio) 33a detected by the displacement sensor 33. The rotational drive of the motor 27 is controlled by feedback control so as to match (see FIG. 7). The control device 40 will be described in detail later.

  The vehicle speed sensor VS is disposed in a speedometer (not shown) and detects the speed of the vehicle. The vehicle speed sensor VS transmits a vehicle speed signal Va, which is an analog electric signal corresponding to the detected vehicle speed, to the control device 40. The vehicle speed sensor VS may be a dedicated sensor for the variable steering angle ratio steering apparatus 1 or a sensor shared with other systems.

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

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

  When the driver rotates the input shaft 11 by operating the steering wheel 2, the intermediate shaft 19 cranks around the axis of the output shaft 17 due to the engagement with the slider 21 of the coupling 16 of the input shaft 11. . 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 shaft center of the input shaft 11 changes in the range indicated by reference signs A0 to A2 in FIGS. 3 and 4 due to the eccentric cam action of the support member 14. If the eccentricity a between the input and output shafts is appropriately determined by changing the shaft center of the input shaft 11 and the input shaft 11 and the output shaft 17 are eccentric to each other, the input shaft 11 and the output shaft 17 The rotation angles are not consistent. Moreover, the change in the angle of the output shaft 17 when the input shaft 11 is rotated by equal angles gradually increases (see solid lines a1 and a2 in FIG. 6).

  When the eccentricity a of the shaft center of the input shaft 11 and the output shaft 17 is continuously changed in the range of a2 to a0 (a2> a1> a0 = 0), the output shaft with respect to the rotation angle of the input shaft 11 The rotational angle ratio β / α of 17, that is, the practical steering angle ratio can be continuously changed. If the eccentricity a between the input and output shafts is increased, the rate of change of the output angle β with respect to the input angle α is gradually increased. If the eccentricity a between the input and output shafts is set to 0, a one-dot chain line (a0 in FIG. ), The input angle α and the output angle β are equal.

  When the change in the steering angle ratio is controlled to be, for example, a0 side in the low-speed traveling region and a2 side in the high-speed traveling region, the rack stroke with respect to the steering angle α of the steering wheel is compared with the conventional steering device in the low-speed traveling region. Therefore, it is possible to realize a more sensitive (quick) characteristic by setting a larger value. Further, in a high-speed traveling region, the rack stroke with respect to the steering angle α of the steering wheel can be set smaller than that of a conventional steering device, and a further insensitive characteristic can be realized. Therefore, the relationship between the practical steering angle and the traveling speed can be made flat.

Next, a control device 40 to which the electronic device according to the present invention is applied will be described with reference to FIG.
As shown in FIG. 7, the control device 40 includes a main CPU 41 that is normally used, and a sub CPU 42 that performs mutual fault detection between the main CPU 41, and further, the main CPU 41 or the sub CPU 42 fails. A backup CPU 43 is used for use. The main CPU 41, the sub CPU 42, and the backup CPU 43 are connected to the switching circuit 44, respectively.

  The switching circuit 44 is connected to the motor driving circuit 45 and has a switching switch (not shown). Either the motor driving signal 41 a output from the main CPU 41 or the motor driving signal 43 a output from the backup CPU 43 is selected. Is output to the motor drive circuit 45. The motor drive circuit 45 is constituted by a bridge circuit composed of switching elements of four FETs, and is connected to a battery power source (not shown). Based on a signal from the switching circuit 44, the motor drive circuit 45 supplies current to the motor 27 to 27 is driven.

  The main CPU 41 and the sub CPU 42 are connected to the EPS motor drive circuit 47 through a gate drive circuit 46 for driving the EPS motor 8. The EPS motor drive circuit 47 is composed of a bridge circuit composed of four FET switching elements, and is connected to a battery (not shown), and supplies current to the EPS motor 8 based on an EPS drive signal 41b from the main CPU 41. Thus, the EPS motor 8 is driven. Further, between the EPS motor drive circuit 47 and the EPS motor 8, motor current detection 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 detection 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 eccentric amount of the input shaft 11 (FIG. 2) detected by the displacement sensor 33 to the main CPU 41, sub CPU 42, and 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 outputs a steering torque signal Ta from the steering torque sensor TS 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.

  As shown in FIG. 8, the main CPU 41 controls the variable steering angle ratio device 10 so as to control the target eccentricity amount determination unit 51, the deviation calculation unit 52, the PID control unit 53, the PWM signal generation unit 54, and the gate drive. A circuit 55 is provided. In addition, in order to perform EPS control, a target current setting unit 56, a deviation calculation unit 57, a PID control unit 58, and a PWM signal generation unit 59 are provided. Further, a sub CPU mutual monitoring unit 60 for detecting a fault mutually with the sub CPU 42 and a backup CPU fault detecting unit 61 for detecting a fault of the backup CPU 43 are provided.

  First, the control of the variable steering angle ratio device 10 will be described. The target eccentricity determination unit 51 includes storage means such as a ROM, and the correspondence between the vehicle speed signal Va set in advance based on experimental values or design values and the target eccentricity. Data (conversion table) to be 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 calculation unit 52. Here, the target eccentricity is associated with a small value in the case of a low speed with a large road reaction force, and a large value in the case of a high speed in order to ensure stability during traveling. It is associated. 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 obtains a deviation between the target eccentricity signal 51a and the eccentricity signal 33a indicating the actual eccentricity detected by the displacement sensor 33 (corresponding to the actual steering angle ratio), and outputs a deviation signal 52a. The eccentricity signal 33a is output to the deviation calculator 52 via the actual steering angle ratio input circuit 48. The PID 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 current value of the current supplied to the motor 27 in order to make the deviation close to zero. And output.

  The PWM signal generation unit 54 outputs a PWM (pulse width modulation) signal 54 a for performing PWM operation of the motor 27 to the gate drive circuit 55 based on the drive control signal 53 a. The gate drive circuit 55 drives the gate of each FET of the motor drive circuit 45 based on the PWM signal 54a and outputs an electric motor drive signal 55a for switching the FET to the switching circuit 44.

  Subsequently, the EPS control process will be described. The target current setting unit 56 includes a storage unit such as a ROM, and data corresponding to the steering torque signal Ta set in advance based on experimental values or design values and the target eccentricity ( Conversion table). Then, the target current setting unit 56 reads the corresponding target current value using the steering torque signal Ta as an address, and outputs the target current signal 56 a to the deviation calculation unit 57.

  The deviation calculating unit 57 obtains a deviation between the target current signal 56 a and the current signal 71 a supplied to the EPS motor 8 by the motor current detecting unit 71, and outputs the deviation signal 57 a to the PID control unit 58. The PID control unit 58 performs processing such as proportionality, integration, and differentiation on the deviation signal 57a, and generates a drive control signal 58a indicating the direction and current value of the current supplied to the EPS motor 8 in order to make the deviation close to zero. Generated and output to the PWM signal generator 59.

  The PWM signal generation unit 59 outputs a PWM (pulse width modulation) signal 59a for performing PWM operation of the EPS motor 8 to the gate drive circuit 46 based on the drive control signal 58a. The gate drive circuit 46 drives the gate of each FET of the EPS motor drive circuit 47 based on the PWM signal 59 a and outputs an electric motor drive signal 46 a for switching the FET to the EPS motor drive circuit 47.

  In addition, in the main CPU 41, the sub CPU mutual monitoring unit 60 performs mutual fault detection with the sub CPU 42. Further, the backup CPU failure detection unit 61 detects a failure of the backup CPU 43. As described above, the main CPU 41 performs a great amount of processing.

  Further, as the sub CPU 42 and the backup CPU 43, CPUs having the same structure are used, and each has a sub program control unit 65, a backup program control unit 66, and a discrimination port 67. The “program corresponding to the sub CPU” of the present invention is written in the sub program 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 unit 65 in the sub CPU 42 exchanges fault detection signals 42 a with the sub CPU mutual monitoring unit 60 in the main CPU 41, and performs mutual fault detection. When a failure is detected in the main CPU 41, a failure signal 42b is output to the switching circuit 44. In response to the failure signal 42b, the switching circuit 44 stops the output of the motor drive signal 41a output to the motor drive circuit 45. Instead, the motor drive signal 43a of the backup CPU 43 is output to the motor drive circuit 45. In the sub CPU 42, the backup program control unit 66 is not performing work.

  On the other hand, the backup program control unit 66 in the backup CPU 43 generates an electric motor drive signal 43a for driving the motor 27 and outputs it to the switching circuit 44 when at least one of the main CPU 41 and the sub CPU 42 fails. Yes. During normal operation, 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 the motor drive circuit 45. 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 an electric motor driving signal 43a from the backup CPU 43 is output to the electric motor driving circuit 45 in place of the electric motor driving signal 41a from the main CPU 41. Is done. 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 main CPU 41 cannot control the variable steering angle ratio device 10. . Therefore, 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 (maximum eccentricity side) from the viewpoint of fail-safe, and the switching circuit 44 Is output. In generating the electric motor drive signal 43a, feedback control using the eccentric amount signal 33a output from the actual steering angle ratio input circuit 48 is performed. In the backup CPU 43, the subprogram control unit 65 is not working.

  Thus, the processing amount in the sub CPU 42 and the backup CPU 43 is small. Therefore, even if these are manufactured as CPUs having the same structure and programs that are not used for processing are written, there is no waste.

  Further, the determination ports 67 and 67 in the sub CPU 42 and the backup CPU 43 are supplied with a determination voltage from a substrate (not shown). Which of the sub CPU 42 and the backup CPU 43 is used is determined by the discrimination voltage given from the substrate. Now, a voltage of 0V is applied to the determination port 67 in the sub CPU 42, in other words, it is grounded, and a voltage of 5V is applied to the determination port 67 in the backup CPU 43. That is, when the CPU is installed on the substrate, a voltage of 0 V is automatically applied to the discrimination port 67 of the CPU installed at the position where the sub CPU 42 should be installed. On the other hand, a voltage of 5V is automatically applied to the discrimination port 67 of the CPU installed at the position where the backup CPU 43 should be installed.

  The determination 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 (S 1). When the process is started, a discrimination voltage applied to the discrimination port 67 is detected (S2). As a result, if the determination voltage is 0 V, it is used as the sub CPU 42, so the sub program is executed (S3). On the other hand, if the discrimination voltage is 5V, it is used as the backup CPU 43, so 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 is finished (S5). As a result, if the control or the like has not ended, the process returns to step S2 to detect the discrimination voltage applied to the discrimination port 67. On the other hand, if control etc. are complete | finished, a discrimination | determination process will be complete | finished (S6). In this way, the sub CPU 42 and the backup CPU 43 are automatically discriminated only by installing the same CPU at each position, so that the sub CPU 42 and the backup CPU 43 are not mistakenly attached. 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, and a difference in program writing.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and two or more CPUs having a program with a small amount of processing can be used even in other electronic devices. Any electronic device can be used. Further, although the CPUs used for the sub CPU and the backup CPU have the same structure, they may not have the same structure as long as they have both the sub program control unit and the backup program control unit. Furthermore, if there is a routine common between the subprogram and the backup program, it 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 CPUs having the same structure. On the other hand, the sub CPU and the backup CPU may have other program control units and the like of the sub program control unit and the backup program control unit.

1 is an overall configuration diagram of a variable steering angle ratio steering device according to an embodiment of the present invention. It is a front sectional view of the variable rudder angle ratio device according to the present embodiment. It is a disassembled perspective view of the axial part of the variable steering angle ratio apparatus which concerns on this Embodiment. It is the sectional view on the AA line of FIG. It is explanatory drawing which shows the principle of operation of the variable steering angle ratio steering apparatus which concerns on this Embodiment. It is an input-output angle characteristic figure which shows the steering angle ratio characteristic of the variable steering angle ratio steering apparatus which concerns on this Embodiment. It is a block block diagram of the control apparatus of the variable steering angle ratio steering apparatus which concerns on this Embodiment. It is a block block diagram around the main CPU of the variable steering angle ratio steering apparatus according to the present embodiment. It is a flowchart which shows the discrimination | determination processing procedure in a sub CPU and backup CPU.

Explanation of symbols

1 Variable steering angle ratio steering device 2 Steering wheel (handle)
10 Variable rudder angle ratio device 40 Control device (electronic device)
41 Main CPU
42 Sub CPU (first CPU)
43 Backup CPU (second CPU)
65 Subprogram control unit (first program)
66 Backup program control unit (second program)
67 Discriminating port W Steering wheel

Claims (1)

An electronic device comprising a substrate on which a first CPU and a second CPU are mounted, and performing processing by a first program written in the first CPU and processing by a second program written in the second CPU,
The substrate is configured to give different determination voltages to a position where the first CPU is installed and a position where the second CPU is installed,
The first CPU and the second CPU are the same CPU having a discrimination port in which both the first program and the second program are written and used for inputting the discrimination voltage, and An electronic apparatus that determines which of the first CPU and the second CPU is used based on a discrimination voltage input from a substrate through the discrimination port.

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