JP2013025570A - Electronic control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic control unit for achieving high safety and desired vehicle control by using lockstep processing while suppressing current consumption.SOLUTION: A sub-microcomputer 6 is configured to compare the arithmetic results of a first instruction execution part 6a and a second instruction execution part 6b by lockstep processing. The sub-microcomputer 6 is configured to monitor the control state of a first main microcomputer 3 by the lockstep processing from a virtual CPU, and to, when it is determined that the control state of the first main microcomputer 3 is not normal, reset the first main microcomputer 3. Therefore, the sub-microcomputer 6 is able to monitor the first main microcomputer 3 by the lockstep processing from a virtual CPU (A) virtually constructed inside the sub-microcomputer 6.

Description

  The present invention relates to an electronic control unit including a microcomputer that performs vehicle control.

  In order to realize various controls, techniques related to the present application are provided (see, for example, Patent Documents 1 and 2). Patent Document 1 provides a technology for constructing a virtual CPU. In particular, in an electronic control unit that provides a calculation result to an in-vehicle device, a real CPU, a virtual CPU construction means for constructing a virtual CPU from the real CPU, a first virtual CPU and a first virtual CPU constructed And a second virtual CPU that monitors a first virtual CPU that provides a calculation result. Further, Patent Document 2 provides a lockstep technique that includes at least two instruction execution units and one comparison unit, and compares the operation results of the instruction execution units with the comparison unit.

JP 2011-22934 A Special table 2009-505183

  Usually, the ECU for vehicle control is equipped with a control microcomputer and a monitoring microcomputer for monitoring the control microcomputer. Among a plurality of control systems controlled by the control microcomputer, for the control requiring higher safety such as electronic throttle control, the target control system is monitored using a monitoring microcomputer. In recent years, in the field of vehicle control technology, it has been proposed to add a lockstep process described in Patent Document 2 in order to further improve safety.

  However, when the lock step process is added to the control microcomputer, there is a concern that the control current increases. That is, when the lock step technology is applied to the control microcomputer, the lock step process is applied to a control system that does not require monitoring.

  The present invention has been made in view of the above circumstances, and an electronic control unit that has a special effect of being able to achieve high safety and achieve desired vehicle control using lockstep processing while suppressing current consumption. It is to provide.

  According to the first aspect of the present invention, the first microcomputer performs vehicle control, but the second microcomputer compares the calculation results of the instruction execution unit with each other by lock step processing. The second microcomputer includes virtual CPU construction means for constructing a virtual CPU, and at least a first virtual CPU and a second virtual CPU constructed by the virtual CPU construction means. Then, the first virtual CPU of the second microcomputer monitors at least the control state of the first microcomputer by the lock step process, and when it is determined that the control state of the first microcomputer is not normal, the first microcomputer resets the first microcomputer. After the reset, the first microcomputer can perform normal vehicle control.

  Therefore, the second microcomputer as the monitoring microcomputer performs the lock step process by the first virtual CPU virtually built therein, and monitors the first microcomputer as the control microcomputer. It has a special effect that high safety can be realized using the processing and desired vehicle control can be realized.

  According to the second aspect of the invention, the third microcomputer performs vehicle control of a type different from the vehicle control performed by the first microcomputer, and the second virtual CPU is configured to monitor the control state by the third microcomputer. Thus, the monitoring process can be performed without newly adding a monitoring microcomputer, and the current consumption can be further suppressed.

  According to the third aspect of the present invention, the first microcomputer monitors the control state of the first virtual CPU and resets only the first virtual CPU when it is determined that the first virtual CPU is not normal. One microcomputer and the first virtual CPU can be monitored each other, and the safety can be further improved.

  According to the fourth aspect of the present invention, the first microcomputer monitors the control state of the first virtual CPU, and if it is determined that the first virtual CPU is not normal, the third microcomputer indicates that the first virtual CPU is not normal. Therefore, the third microcomputer can recognize that the first virtual CPU is not operating normally, and can reduce the adverse effect of the third microcomputer on the control system. Moreover, since the first virtual CPU and the second virtual CPU are reset, the monitoring process of the control state of the third microcomputer by the first virtual CPU and the second virtual CPU can be normally performed after the reset.

  According to the fifth aspect of the present invention, the first virtual CPU performs the monitoring process of the first microcomputer using the control information of both the control state of the first microcomputer and the control state of the third microcomputer, thereby controlling the first microcomputer. The safety of the system can be further improved.

  According to the sixth aspect of the invention, the second microcomputer monitors the control state of the first microcomputer by the first virtual CPU, and processes the system different from the first microcomputer by a virtual CPU different from the first virtual CPU. Can be executed.

  According to the seventh aspect of the invention, the first microcomputer performs vehicle control, but the third microcomputer performs vehicle control of a type different from the vehicle control performed by the first microcomputer. The second microcomputer compares the operation results of the instruction execution units with each other by lock step processing using at least two or more instruction execution units and comparison units. The second microcomputer monitors the control state of the first microcomputer by lockstep processing, and resets the first microcomputer when it is determined that the control state of the first microcomputer is not normal, and monitors the control state of the third microcomputer. Since the third microcomputer is reset when it is determined that the control state of the three microcomputers is not normal, both the first microcomputer and the third microcomputer can perform normal vehicle control after the reset.

1 is an electrical block configuration diagram schematically showing a first embodiment of the present invention. Electrical block diagram showing an example of monitoring mode Timing chart showing the flow of lockstep processing FIG. 1 equivalent view schematically showing a second embodiment of the present invention.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. Usually, in order to control a large number of actuators in the vehicle, a vehicle is equipped with several tens or more electronic control units such as an engine control ECU (Electronic Control Unit), a brake control ECU, a body control ECU, and a meter control ECU. These ECUs communicate with each other according to a predetermined communication standard, thereby controlling the entire vehicle. In recent years, ECUs have been integrated for the purpose of cost reduction and the like. Therefore, in the present embodiment, the integrated ECU 1 in which the functions of the engine control ECU, the body control ECU, and the brake control ECU are mounted will be described.

FIG. 1 schematically shows an electrical block configuration in the integrated ECU according to the present embodiment.
The integrated ECU 1 has functions of an engine control ECU, a body control ECU, and a brake control ECU. The integrated ECU 1 is operated by the power supplied from the common power supply circuit 2. The common power supply circuit 2 converts the constant power supply voltage supplied from the battery into a voltage used in each circuit in the integrated ECU 1 and supplies the converted voltage.

  The integrated ECU 1 includes a first main microcomputer 3, a second main microcomputer 4, and a third main microcomputer 5. The first main microcomputer 3 mainly has functions of an engine control ECU such as electronic throttle control. The second main microcomputer 4 mainly includes the function of the brake control ECU. The third main microcomputer 5 mainly includes the function of the body control ECU. These first to third main microcomputers 3 to 5 include CPUs 3a to 5a, ROM (not shown), RAM (not shown), system interface (I / F) circuits 3b to 5b, respectively. In the drawing, the symbols “a” are added to the mounted CPUs of the first to third main microcomputers 3 to 5 and the symbols “b” are added to the system interface circuits.

  In addition, a sub-microcomputer 6 is mounted in the integrated ECU 1 in addition to the first to third main microcomputers 3 to 5. The sub-microcomputer 6 includes therein a plurality of instruction execution units (first instruction execution unit 6a and second instruction execution unit 6b), a comparison unit 6c including a comparator, and a system interface circuit 6d. A virtual CPU (virtual CPU (A) (corresponding to the first virtual CPU) described later, virtual CPU (B) (corresponding to the second virtual CPU), etc.) is constructed in each of 6a and the second instruction execution unit 6b. The first instruction execution unit 6a, the second instruction execution unit 6b, and the comparison unit 6c perform a lock step. The outline of the lock step process by the sub-microcomputer 6 will be described later.

  The system interface circuits 3b to 5b, 6d include an A / D converter (ADC) that converts an analog input signal into digital data and outputs it to its own microcomputer, an input buffer that inputs a digital input signal and outputs it to its own microcomputer, etc. , An output I / F (interface) that outputs an actuator drive signal, and a communication I / F (interface) that performs communication processing with other microcomputers. Although not shown, the integrated ECU 1 is mounted with various peripheral circuits such as a memory such as an EEPROM as well as the common power supply circuit 2, the first to third main microcomputers 3 to 5, and the sub-microcomputer 6 described above.

FIG. 2 shows a specific example of the monitoring mode of the operating state of the first main microcomputer 3 by the sub-microcomputer 6.
The first main microcomputer 3 inputs an accelerator opening signal through an input I / F (ADC) of the system interface circuit 3b. Similarly, the sub-microcomputer 6 inputs the accelerator opening signal through the input I / F (ADC) of the system interface circuit 6d. The first main microcomputer 3 determines the operation amount of the throttle opening when the accelerator opening signal is inputted.

  The throttle opening signal is input to the first main microcomputer 3 through the input I / F of the system interface circuit 3b. This throttle opening signal is also input to the sub-microcomputer 6 through the input I / F of the system interface circuit 6d. Further, the accelerator opening signal and the throttle opening signal acquired by the first main microcomputer 3 may be transmitted to the monitoring sub-microcomputer 6.

  The CPU 3a of the first main microcomputer 3 obtains the opening deviation by comparing the operation amount of the throttle opening and the throttle opening signal, obtains the control amount required for the control motor of the electronic throttle S, and calculates the control amount. The opening of the throttle valve Sa is controlled by converting it into a duty ratio and supplying a current corresponding to the signal to the motor (throttle opening control).

  The sub-microcomputer 6 monitors the throttle opening control state via the system interface circuit 6d. If the monitoring result is abnormal, the sub-microcomputer 6 stops the motor drive or performs power-off control (power-off). As this method, by obtaining the logical sum of the output I / F of the system interface circuit 3b of the first main microcomputer 3 and the output I / F of the system interface circuit 6d, the power supply energization and the validity / invalidity of the motor drive signal are determined. There is a way to switch.

  As another method, communication processing is performed between the communication I / F of the system interface circuit 3b of the first main microcomputer 3 and the communication I / F of the system interface circuit 6d of the sub-microcomputer 6, and the first main microcomputer 3 There is a method in which an instruction for selecting an output I / F with a selection function mounted in the system interface circuit 3b is issued from the sub-microcomputer 6 and the sub-microcomputer 6 directly controls the electronic throttle S.

  FIG. 3 shows the flow of monitoring processing by the lock step of the sub-microcomputer 6. As shown in FIG. 3, the sub-microcomputer 6 causes the first main microcomputer 3 to have the same operation clock by the virtual CPU (A) (VCPU processing 1) using the first instruction execution unit 6a and the second instruction execution unit 6b. Monitor processing by. In this case, the sub-microcomputer 6 compares the monitoring calculation results of the first instruction execution unit 6a and the second instruction execution unit 6b using the comparison unit 6c formed of a comparator, and determines whether or not they are the same calculation result. To do. The sub-microcomputer 6 determines that the monitoring calculation result is normal when the comparison results of the monitoring processing are the same.

  Subsequently, the sub-microcomputer 6 monitors the second main microcomputer 4 with the same operation clock by the virtual CPU (B) (VCPU processing 2) using the first instruction execution unit 6a and the second instruction execution unit 6b. . In this case, the sub-microcomputer 6 uses the comparator comparison unit 6c to compare the monitoring operation results of the first instruction execution unit 6a and the second instruction execution unit 6b, and these monitoring operation results are the same operation result. It is determined whether or not.

The sub-microcomputer 6 determines that the monitoring calculation result is normal when it is determined that the comparison results of the monitoring processing are the same. Subsequently, the sub-microcomputer 6 performs other processing (for example, meter control) by the processing of the VCPU processing 3. In this way, the sub-microcomputer 6 continues the monitoring process. Hereinafter, the example of the aspect of the monitoring method is given.
<Aspects of the monitoring method of the first to third main microcomputers 3 to 5 by the sub-microcomputer 6>
Hereinafter, a monitoring mode example in which the sub-microcomputer 6 serving as the monitoring microcomputer monitors the first and second main microcomputers 3 and 4 serving as the control microcomputer will be described. As an example, the monitoring of the first main microcomputer 3 is shown, but the same applies to the second main microcomputer 4.
<Example 1>
The first main microcomputer 3 outputs a watchdog counter signal (H / L pulse signal), and the sub-microcomputer 6 monitors the watchdog signal. If the watchdog signal disappears, it can be detected that the first main microcomputer 3 is operating abnormally.
<Example 2>
The sub-microcomputer 6 communicates and outputs homework information to the first main microcomputer 3, and the first main microcomputer 3 processes the homework information and transmits it to the sub-microcomputer 6 on the monitoring side. The monitoring side sub-microcomputer 6 checks whether or not the first main microcomputer 3 is operating normally according to whether the answer is correct. If the answer is incorrect, the first main microcomputer 3 is operating abnormally. Can be detected.
<Example 3>
The monitoring side sub-microcomputer 6 acquires the input data and output data of the first main microcomputer 3, and the monitoring side sub-microcomputer 6 uses a simple calculation that is different from the processing performed by the first main microcomputer 3 using the input data. A process is performed to check the difference from the output data of the first main microcomputer 3. If the difference is greatly different from the predetermined range, it is determined that the first main microcomputer 3 is operating abnormally.

  The sub-microcomputer 6 monitors the first main microcomputer 3 according to such a monitoring mode. If the monitoring result is abnormal, the sub-microcomputer 6 performs power-off control, stops the motor drive, and resets the first main microcomputer 3. When the sub-microcomputer 6 determines that the monitoring result is abnormal, the sub-microcomputer 6 controls the output of the first main microcomputer 3 through the communication I / F of the system interface circuits 3b and 6d as described above, and then the first main microcomputer 3 The microcomputer 3 may be reset.

  Conventionally, when a monitoring function is added to each of the first and second main microcomputers 3 and 4, the first and second main microcomputers 3 and 4 need to operate at 32 bits (actual operation) +32 bits (monitoring process). As a result, the total number of operating bits increases and the overall power consumption increases. According to the present embodiment, for example, the CPUs 3a and 4a of the first and second main microcomputers 3 and 4 are operated with 32 bits, and the first instruction execution unit 6a and the second instruction execution unit 6b of the sub-microcomputer 6 are operated. By operating each with 32 bits, the total number of actual operation bits can be reduced while adding a monitoring function to the first and second main microcomputers 3 and 4, respectively, thereby reducing power consumption. As a result, high safety can be realized using lockstep processing while suppressing current consumption, and desired vehicle control can be realized.

  According to this embodiment, it has the following features. The sub-microcomputer 6 compares the operation results of the first instruction execution unit 6a and the second instruction execution unit 6b with each other by lock step processing. The sub-microcomputer 6 monitors the control state of the first main microcomputer 3 by lockstep processing by the virtual CPU, and resets the first main microcomputer 3 when determining that the control state of the first main microcomputer 3 is not normal. After the reset, the first main microcomputer 3 can perform normal vehicle control.

  Accordingly, the sub-microcomputer 6 can monitor the first main microcomputer 3 by performing the lock step process by the virtual CPU (A) virtually built therein, so that it is high using the lock step process while suppressing the current consumption. Safety can be realized and desired vehicle control can be realized. In other words, the current consumption can be suppressed by performing the lock step process not by the first main microcomputer 3 that performs complicated control such as electronic throttle control or other engine control but by the sub-microcomputer 6 that is relatively light processing such as monitoring the electronic throttle. .

  The first main microcomputer 3 and the second main microcomputer 4 perform different types of vehicle control. In this case, the first main microcomputer 3 and the second main microcomputer 4 are different from the virtual CPU (A) (VCPU process 1) that performs the monitoring process of the first main microcomputer 3. Since the monitoring process of the second main microcomputer 4 is performed by the virtual CPU (B) (VCPU process 2), it is possible to perform the monitoring process without newly adding a monitoring microcomputer, and further suppress current consumption. Can be planned.

Further, when there is a margin in the processing load of the sub-microcomputer 6, a virtual CPU (C) may be constructed to perform other processing.
(Modification of the first embodiment)
In the first embodiment, the sub-microcomputer 6 individually monitors and controls the control state of the first main microcomputer 3, but in this modification, the sub-microcomputer 6 is controlled by the virtual CPU (A) by the first main microcomputer 3. The monitoring process of the first main microcomputer 3 is performed using the control information of both the control state of the microcomputer 3 and the control state of the second main microcomputer 4. This is because it is more desirable to perform the monitoring process of one first main microcomputer 3 taking into account the related control information. For example, the following cases may be mentioned.

For example, the sub-microcomputer 6 is
(1) Normal reception of watchdog counter signal information from both the first main microcomputer 3 and the second main microcomputer 4 (2) Acquisition of deceleration control information by brake control from the second main microcomputer 4 for brake control (3) No. 1 When the main microcomputer 3 receives a control signal that satisfies all the conditions (1) to (3), such as increasing the throttle opening of the electronic throttle S, or maintaining a high opening above a certain level for a predetermined time or more. If there is, the sub-microcomputer 6 determines that the first main microcomputer 3 is operating abnormally, and resets the first main microcomputer 3 by instructing the reset. The safety of the control system can be further improved by combining the related control information and monitoring the operation of the first main microcomputer 3.

(Second Embodiment)
FIG. 4 shows a second embodiment of the present invention, which is characterized in that an ECU having a different function instead of an integrated ECU is mounted on a separate board. In the above-described embodiment, the integrated ECU 1 has been described. However, the integrated ECU 1 may be configured using one or two or more substrates.

  For example, as shown in FIG. 4, the engine control ECU 7, the brake control ECU 8, the body control ECU 9, and the monitoring control ECU 10 are configured on separate boards, for example, the engine control ECU 7, the brake control ECU 8, the body control ECU 9, You may make it implement | achieve vehicle control by mutually communicating between ECU10 for control.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows, for example.

  In the above-described embodiment, an integrated ECU 1 that integrates the functions of engine control, brake control, and body control, or a mode in which these control functions are mounted on separate boards as an engine control ECU 7, a brake control ECU 8, and a body control ECU 9, respectively. doing.

  Among these, the monitoring process may be performed separately for a process with a relatively high importance level that requires a lock step and a process with a relatively low importance level that does not require a lock step process. Controls that should be monitored using the lock step include, for example, electronic throttle control, brake control, electric power steering control, and air bag control. Since these control processes are related to safety performance, they are highly important, and safety can be improved by providing a lockstep function.

  The control which may use the lock step function but may omit it is, for example, a sensing process by a meter, an air conditioner, a tire pressure monitor, and a sonar around the vehicle. If monitoring is performed without providing a lockstep function, an extra function can be omitted. In such a case, by monitoring the control state separately whether the lock step function is necessary or not, the control state can be monitored by providing the lock step only for the necessary control, and desired vehicle control can be realized.

Although the embodiment in which the sub-microcomputer 6 monitors the operations of the first to third main microcomputers 3 to 5 has been shown, conversely, the first main microcomputer 3 may have a function of monitoring the sub-microcomputer 6. Hereinafter, a specific example of a monitoring method in which the sub-microcomputer 6 serving as the monitoring microcomputer monitors the first main microcomputer 3 serving as the control microcomputer will be described.
<Specific example of monitoring method of sub-microcomputer 6 by first main microcomputer 3>
<Example 4>
The first main microcomputer 3 checks the watchdog counter signal of the virtual CPU (A) by the sub-microcomputer 6, and if the first main microcomputer 3 determines that the sub-microcomputer 6 is operating abnormally, The virtual CPU (A) is reset and the first main microcomputer 3 is reset by itself.
<Example 5>
The simple calculation processing acquired in the lock step by the virtual CPU (A) of the sub-microcomputer 6 described in <Example 3> of the above-described embodiment is also checked on the first main microcomputer 3 side. The virtual CPU (A) is reset and the first main microcomputer 3 is reset by itself.

  In such a case, when the first main microcomputer 3 determines that the virtual CPU (A) is not operating normally, it notifies the other second main microcomputer 4 and the third main microcomputer 5 of this fact. Then, since the second main microcomputer 4 and the third main microcomputer 5 can recognize that the virtual CPU (A) is not operating normally, the adverse effect of the second main microcomputer 4 and the third main microcomputer 5 on the control system is reduced. it can.

  At this time, the first main microcomputer 3 instructs the virtual CPU (A) and virtual CPU (B) of the sub-microcomputer 6 to be reset via the system I / F 3b, and both the virtual CPU (A) and virtual CPU (B) are instructed. It is good to reset. Then, after the reset, the monitoring process of the control state of the second main microcomputer 4 and the third main microcomputer 5 by the virtual CPU (A) and the virtual CPU (B) can be normally performed.

  In the above <Example 4> and <Example 5>, the monitoring example of the sub-microcomputer 6 by the first main microcomputer 3 is given. However, the second main microcomputer 4 or the third main microcomputer 5 may monitor the sub-microcomputer 6. It is the same.

  Further, when the comparison unit 6c detects a mismatch between the operation results of the first instruction execution unit 6a and the second instruction execution unit 6b, the first instruction execution unit 6a and the second instruction execution unit 6b are reset. Good. In that case, the first main microcomputer 3 and the second main microcomputer 4 may be notified in advance.

  The first instruction execution unit 6a and the second instruction execution unit 6b installed in the sub-microcomputer 6 are not limited to these two. Further, the number of virtual CPUs executed by the first instruction execution unit 6a and the second instruction execution unit 6b is not limited to the number shown in the above-described embodiment. The first to third main microcomputers 3 to 5 and the sub-microcomputer 6 may be communicably connected or may be mixed in one board and connected by wiring. Further, the lock step technique may be applied to the first to third main microcomputers 3 to 5.

  In the drawings, 1 is an integrated ECU (electronic control unit), 2 is a common power supply circuit, 3 is a first main microcomputer (first microcomputer in the claims), and 4 is a second main microcomputer (third microcomputer in the claims). 5 is a third main microcomputer, 6 is a sub-microcomputer (second microcomputer in the claims), 6a is a first instruction execution unit, 6b is a second instruction execution unit, 6c is a comparison unit (comparison unit), and 6d is a system. An interface circuit, 7 is an engine control ECU, 8 is a brake control ECU, 9 is a body control ECU, and 10 is a monitoring ECU.

Claims (7)

A first microcomputer for controlling the vehicle;
A second microcomputer that compares the operation results of the instruction execution unit with each other by lockstep processing using at least two or more instruction execution units and a comparison unit;
The second microcomputer includes virtual CPU construction means for constructing a virtual CPU, and at least a first virtual CPU and a second virtual CPU constructed by the virtual CPU construction means,
The first virtual CPU of the second microcomputer monitors at least the control state of the first microcomputer by the lock step process, and resets the first microcomputer when determining that the control state of the first microcomputer is not normal. An electronic control unit. A third microcomputer for performing vehicle control of a type different from the vehicle control performed by the first microcomputer;
The electronic control unit according to claim 1, wherein the second virtual CPU monitors a control state by the third microcomputer.   The first microcomputer monitors a control state of the first virtual CPU and resets only the first virtual CPU when it is determined that the first virtual CPU is not normal. 3. The electronic control unit according to 2.   The first microcomputer monitors the control state of the first virtual CPU, and if it is determined that the first virtual CPU is not normal, notifies the third microcomputer that the first virtual CPU is not normal, The electronic control unit according to claim 2, wherein the first virtual CPU and the second virtual CPU are reset.   The first virtual CPU performs monitoring processing of the first microcomputer by using control information of both the control state of the first microcomputer and the control state of the third microcomputer. Or the electronic control unit of 4.   The second microcomputer monitors the control state of the first microcomputer by the first virtual CPU, and executes processing of a system different from the first microcomputer by a virtual CPU different from the first virtual CPU. 6. The electronic control unit according to claim 1, wherein the electronic control unit is characterized in that: A first microcomputer for controlling the vehicle;
A third microcomputer for performing vehicle control of a type different from the vehicle control performed by the first microcomputer;
A second microcomputer that compares the operation results of the instruction execution unit with each other by lockstep processing using at least two or more instruction execution units and a comparison unit;
The second microcomputer monitors the control state of the first microcomputer by the lock step process and resets the first microcomputer when it is determined that the control state of the first microcomputer is not normal. An electronic control unit characterized in that when the control state is monitored and it is determined that the control state of the third microcomputer is not normal, the third microcomputer is reset.

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