JP2016162330A - Electronic controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent omission of a task while suppressing reduction of control performance.SOLUTION: An electronic controller comprises: storage means in which a task to be executed for every constant time, is stored; and processing means for executing the task for every constant time. In plural functions for forming the task, a first kind logic function which cannot be simplified, and a second kind logic function which has a less affection to control of a control target even when it is simplified, are contained. The storage means stores, as the second kind logic function, a normal logic function which is not simplified and a simple logic function which is simplified. As execution modes of the task, a normal logic mode (S150) for executing the normal logic function as the second kind logic function, and the simple logic mode (S160-S200) for executing the simple logic function, are provided. The processing means switches the execution mode from the normal logic mode to the simple logic mode, when it is determined that omission of the task may occur.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electronic control device.

  For example, in an electronic control device that controls a vehicle engine, a CPU (Central Processing Unit) of a microcomputer executes a task for controlling the engine at regular intervals. A task executed at regular intervals is called a regular task.

  In recent years, the control software for the powertrain system has become larger and the processing load on the CPU tends to increase. When the processing load on the CPU increases, there is a possibility that a task (so-called task omission) in which a task to be executed every predetermined time cannot be executed every predetermined time is generated. When a task omission occurs, the task is not executed at the original execution timing, so that it is impossible to perform good control of the controlled object.

  On the other hand, for example, Patent Document 1 describes a technique of stopping execution of a part of a control program when a processing load (calculation load) is larger than a threshold value.

JP 2002-366374 A

  The technique of Patent Document 1 does not prevent task omission, and when the processing load is large, a part of the control program is not executed, so that the control function by the control program that is no longer executed is lost. As a result, the control performance is significantly reduced.

  Accordingly, an object of the present invention is to prevent task omission while suppressing a decrease in control performance.

  An electronic control device according to a first aspect of the present invention comprises storage means for storing a task to be executed at regular intervals in order to control a controlled object, and processing means for executing the tasks at regular intervals. As the plurality of functions constituting the task, a first type logic function that is a logic function that cannot be simplified, and a second type logic that is a logic function that has little influence on the control of the control target even if simplified. There is a function.

  The storage means stores, as the second type logic function, a normal logic function for a normal operation that is not simplified and a simple logic function for a calculation simplified more than the normal operation. In addition, as the execution mode when the processing means executes the task, the normal logic mode that executes the normal logic function as the second type logic function and the simple logic function that executes the simple logic function as the second type logic function. There is a logic mode.

  The processing unit includes a determination unit and a mode switching unit. The determination unit determines whether or not there is a possibility that a task omission that cannot be executed at regular time intervals may occur. The mode switching means switches the task execution mode from the normal logic mode to the simple logic mode when the determination means determines that there is a possibility of task omission.

  According to this electronic control device, when the processing load of the processing means increases and the possibility of task omission occurs, among the functions constituting the task, the second type logic function other than the first type logic function As for, instead of the normal logic function, a simplified logic function simplified than the normal logic function is executed.

  For this reason, the processing load of the processing means is reduced, and the occurrence of task omission is prevented. In addition, since the processing of the second type logic function is not executed at all, the simple logic function is executed as the second type logic function, so that it is possible to suppress a decrease in control performance. Therefore, task omission can be prevented while suppressing a decrease in control performance.

  In addition, the code | symbol in the parenthesis described in the claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this invention is limited is not.

It is a block diagram showing the structure of the electronic control apparatus of embodiment. It is explanatory drawing explaining a logic table. It is a flowchart of a task process. It is a flowchart of a logic mode determination process.

Hereinafter, an electronic control device according to an embodiment to which the present invention is applied will be described.
An electronic control device (hereinafter referred to as ECU) 1 of the embodiment shown in FIG. 1 is an ECU that controls an engine of a vehicle, for example, and a microcomputer (hereinafter referred to as microcomputer) 3 is used as a processing unit that controls the operation of the ECU 1. Prepare. Note that ECU is an abbreviation for “Electronic Control Unit”. The microcomputer 3 includes a CPU 5 as processing means, a ROM 7 as storage means in which a program executed by the CPU 5 is stored, and a RAM 9 in which calculation results by the CPU 5 are stored.

  The ECU 1 is connected with an intake air amount sensor 11, a crank angle sensor 12, a water temperature sensor 13, an intake air temperature sensor 14, an air-fuel ratio sensor 15, and the like as sensors for detecting information used for controlling the engine. The ECU 1 is connected with an injector 17 as a drive target.

  Signals from the sensors 11 to 15 are input to the microcomputer 3 via a signal input circuit (not shown). In the microcomputer 3, the CPU 5 calculates the fuel injection amount for the engine based on the signals from the sensors 11 to 15 by executing the program in the ROM 7, and controls the driving of the injector 17 based on the calculation result. . Although not shown, the ECU 1 is also provided with a drive circuit that outputs a drive signal to the injector 17 in response to an injection command signal from the microcomputer 3.

The engine control program stored in the ROM 7 of the microcomputer 3 includes a task to be executed at regular intervals (hereinafter referred to as a regular task).
The engine control logic assigned to the periodic task is classified into a first type logic that requires normal calculation even when the CPU 5 is heavily loaded, and a second type logic that has little influence on engine control even with simple calculation. ing. The first type logic is essential logic that cannot be simplified in engine control, and the second type logic is logic that has little influence on engine control even if simplified.

  For this reason, among the functions for engine control constituting the periodic task, the first type logic function (hereinafter also referred to as an essential logic function) that is a function of the first type logic cannot be simplified. On the other hand, the second type logic function, which is a function of the second type logic, has little influence on the engine control even if simplified, and can therefore be simplified and executed when the CPU 5 is under a high load. Further, among the first type logic function and the second type logic function, there are at least a plurality of second type logic functions.

  Therefore, in the ROM 7 of the microcomputer 3, for each of the second type logic functions constituting the periodic task, a normal logic function for normal calculation that is not simplified and a calculation that is simplified more than normal calculation are provided. Simple logic functions are stored.

Specifically, the normal logic function and the simple logic function are stored in the ROM 7 in the form of a logic table shown in FIG.
As shown in FIG. 2, the logic table includes a normal logic table that records a normal logic function for each of the second type logic functions, and a simple logic table that records a simple logic function for each of the second type logic functions. It consists of two. In FIG. 2, “Func A ()”, “Func B ()”, “Func C ()”, “Func D ()”... Are normal logic functions, and “Func a ()”, “Func b” “()”, “Func c ()”, “Func d ()”... Are simple logic functions. The ROM 7 stores both the normal logic function and the simple logic function as the second type logic function. The normal logic function corresponds to the original type 2 logic function, and a simplified logic function is a simplified version of the normal logic function.

And the processing time of the simple logic function is also recorded on each simple logic function in the simple logic table.
In the simple logic table, the recording order of the simple logic functions is in the order of processing time. The processing order of the simple logic functions is the recording order of the simple logic functions in the simple logic table (that is, the processing time is the smallest) as shown in the “processing order” column at the left end in FIG. .

  For example, the first type logic function includes a basic injection amount calculation function for calculating a basic injection amount, which is a basic value of the injection amount, from the intake air amount and the rotation speed of the engine, and a plurality of corrections that have already been calculated. There is a control injection amount calculation function that corrects the basic injection amount using a coefficient and calculates a final injection amount used for drive control of the injector 17.

The second type logic function is a function for calculating the plurality of correction coefficients.
For example, as the second type logic function, a function (for example, Func A (), Funca ()) that calculates a correction coefficient based on the engine water temperature, or a function that calculates a correction coefficient based on the intake air temperature of the engine. (For example, Func B (), Func b ()), a function for calculating a correction coefficient based on the elapsed time since the engine start (for example, Func C (), Func c ()), Functions for calculating correction coefficients (for example, Func D (), Func d ()).

Next, periodic task processing executed by the CPU 5 will be described with reference to FIG.
In the microcomputer 3, a wake-up request for a regular task is generated every predetermined time, and when the wake-up request is generated, the CPU 5 starts executing the periodic task shown in FIG.

As shown in FIG. 3, in the periodic task, the CPU 5 first calculates a margin time for the periodic task in S110. The spare time is the time from the previous end of the periodic task to the start of this time. For example, when the periodic task ends, the free run timer value in the microcomputer 3 is stored in the RAM 9 as the task end time, and is stored in the RAM 9 from the free run timer value when the current wakeup request is generated. A value obtained by subtracting the task end time can be calculated as a margin time.

In step S120, the CPU 5 executes the essential logic function. As described above, the essential logic function is the first type logic function.
In the next S130, the CPU 5 performs a logic mode determination process shown in FIG.

  The execution mode when the CPU 5 executes the periodic task includes a normal logic mode and a simple logic mode. The normal logic mode is a mode in which the normal logic function is executed as the second type logic function, and the simple logic mode is a mode in which the simple logic function is executed as the second type logic function. The logic mode determination process is a process for switching the execution mode of the regular task between the normal logic mode and the simple logic mode.

  As shown in FIG. 4, in the logic mode determination process, the CPU 5 determines in S210 whether or not the current execution mode is the simple logic mode, and if it is not the simple logic mode (that is, in the normal logic mode). If there is), the process proceeds to S220.

  In S220, the CPU 5 determines whether or not the margin time calculated in S110 of FIG. 3 is less than a specified value. If the allowance time is not less than the specified value (S220: NO), the logic mode determination process is terminated as it is. If the allowance time is less than the specified value (S220: YES), the task missing from the periodic task occurs. The process proceeds to S230.

  In S230, the CPU 5 cancels the normal logic mode and sets it to the simple logic mode in order to prevent task omission. That is, the execution mode of the periodic task is switched from the normal logic mode to the simple logic mode. Thereafter, the logic mode determination process is terminated.

If the CPU 5 determines in S210 that the current execution mode is the simple logic mode, the process proceeds to S240.
In S240, the CPU 5 determines whether or not the current processing load of the CPU 5 is in a low load state. The low load state is a processing load state in which there is no possibility of a task omission of a periodic task.

For example, in the microcomputer 3, the processing load of the CPU 5 changes according to a specific input signal.
For example, a signal (hereinafter referred to as a crank angle signal) output from the crank angle sensor 12 generates a pulse every time the crankshaft of the engine rotates by a predetermined angle. In the microcomputer 3, an interrupt is generated every time a pulse is generated in the crank angle signal, and the CPU 5 performs an interrupt process. For this reason, as the engine speed increases, the frequency of interruptions increases and the processing load on the CPU 5 increases. Therefore, in S240, for example, the CPU 5 determines whether or not the engine speed detected based on the pulse generation interval in the crank angle signal is equal to or smaller than a predetermined value, and if the engine speed is equal to or smaller than the predetermined value. It is determined that the load is low.

  If the CPU 5 determines in S240 that it is not in a low load state, the CPU 5 terminates the logic mode determination process as it is. If it is determined that the load is in a low load state, a task missing from a periodic task occurs. If it is determined that there is no longer a possibility to do so, the process proceeds to S250.

  In S250, the CPU 5 cancels the simple logic mode and sets the normal logic mode. That is, the execution mode of the periodic task is switched from the simple logic mode to the normal logic mode. Thereafter, the logic mode determination process is terminated.

Returning to the description of FIG. CPU5 will complete | finish the logic mode determination process of FIG. 4 in S130, and will progress to S140.
In S140, the CPU 5 determines whether or not the current execution mode is the simple logic mode. If it is not the simple logic mode (that is, if it is the normal logic mode), the CPU 5 proceeds to S150.

  In S150, the CPU 5 executes each of the normal logic functions recorded in the above-described normal logic table (FIG. 2) as each of the second logic functions, and then ends the periodic task.

On the other hand, if the CPU 5 determines in S140 that the current execution mode is the simple logic mode, the process proceeds to S160.
In S160, the CPU 5 selects one simple logic function to be executed from the above-described simple logic table (FIG. 2), and reads the processing time of the selected simple logic function. The rules for selecting a simple logic function in S160 are as follows.

・ Select from the smallest processing time.
However, if the next start function information is stored in the RAM 9 in the later-described periodic task in S200 described later, the simple logic function indicated by the next start function information is selected in order. The next start function information indicates a simple logic function having the shortest processing time next to the simple logic function last executed in the previous periodic task among the simple logic functions recorded in the simple logic table. The next start function information is deleted when the simple logic mode returns to the normal logic mode.

  Then, in the next S170, the CPU 5 measures the remaining time from the present to the next scheduled start time of the periodic task (specifically, the next scheduled wakeup request generation time). For example, the current free-run timer value is subtracted from the free-run timer value corresponding to the scheduled time for the next wake-up request, and the subtracted value is multiplied by the resolution time of the free-run timer value to calculate the remaining time. To do. Further, in S170, the CPU 5 determines whether or not the time obtained by subtracting the predetermined time Tα from the measured remaining time (hereinafter referred to as processable time) is equal to or longer than the processing time of the simple logic function selected in S160. The predetermined time Tα is the maximum processing time required from the completion of the execution of the simple logic function in S180 described later to the end of the periodic task without executing the next simple logic function. Therefore, the processable time (= remaining time−Tα) can be used for the execution of the simple logic function as long as the periodic task can be completed by the next scheduled start time of the periodic task. It's time.

  If the CPU 5 determines in S170 that the processable time is equal to or longer than the processing time, even if the simple logic function selected in S160 is executed, the CPU 5 executes the periodic task until the next wake-up request is generated. If it is determined that the process can be completed, the process proceeds to S180, and the simple logic function selected in S160 is executed.

In step S190, the CPU 5 determines whether or not the execution of all the simple logic functions recorded in the simple logic table is completed, and determines that the execution of all the simple logic functions is not completed. If so, the process returns to S160. In S <b> 160 in this case, the CPU 5 selects a simple logic function having the next shortest processing time after the simple logic function selected in the previous S <b> 160.

If the CPU 5 determines in S190 that the execution of all the simple logic functions has been completed, the CPU 5 ends the periodic task.
On the other hand, if it is determined in S170 that the processable time is not equal to or longer than the processing time, the CPU 5 proceeds to S200 without executing the simple logic function selected in S160. In this case, if the simple logic function selected in S160 is executed, the periodic task cannot be completed until the next wake-up request is generated, causing a task omission.

  In S200, the CPU 5 stores the information indicating the simple logic function selected in S160 in the RAM 9 as the above-mentioned next start function information, and then ends the periodic task. In this case, in the next periodic task, in the first S160, the simple logic functions indicated by the next start function information are selected in order. Therefore, the next task is executed from the simple logic function in the next order of the simple logic function executed last in the previous periodic task. As the next start function information, for example, the processing order of the corresponding simple logic function (see the leftmost column in FIG. 2) is stored.

  In the ECU 1 as described above, when the CPU 5 of the microcomputer 3 determines that there is a possibility that the task of the periodic task may be lost (S220: YES), the execution mode of the periodic task is switched from the normal logic mode to the simple logic mode. (S230). In the case of the simple logic mode in the regular task, a simple logic function obtained by simplifying the normal logic function is executed as the second type logic function (S160 to S190).

  For this reason, the processing load of the CPU 5 is reduced (specifically, the processing time of the periodic task is shortened), and the occurrence of task omission is prevented. In addition, the process of the second type logic function is not stopped at all, but the simple logic function is executed as the second type logic function, so that it is possible to suppress a decrease in the control performance of the engine. Therefore, task omission can be prevented while suppressing a decrease in control performance.

  Further, when the execution of the periodic task is started, the CPU 5 measures the time from the previous end of the periodic task to the start of this time as an allowance time (S110), and if the measured allowance time is less than the specified value. For example, it is determined that there is a possibility that the task omission of the periodic task may occur (S220). Therefore, it is possible to correctly determine whether or not there is a possibility of task omission.

  Further, in the periodic task, the CPU 5 executes the first type logic function before the second type logic function (S120). In the regular task in the simple logic mode, the simple task is completed as much as possible within a range in which the task can be completed by the next scheduled start time of the task after completing the execution of the first type logic function. The logic function is executed (S160 to S190). For this reason, it is possible to execute as many simple logic functions as possible and suppress the influence on the control while preventing task omission.

  In addition, in the regular task in the simple logic mode, the CPU 5 executes the simple logic functions in descending order of processing time. For this reason, more simple logic functions can be executed.

Further, when all the simple logic functions cannot be executed in the regular task in the simple logic mode (S170: NO), the CPU 5 determines the last simple logic function executed in the current regular task. Information indicating the next simple logic function is stored in the RAM 9 as next start function information (S200). Then, the CPU 5 executes the next regular task from the simple logic function indicated by the next start function information (that is, the simple logic function in the next order of the simple logic function executed last in the previous regular task) (S160). , S180). For this reason, all the simple logic functions can be executed by a plurality of periodic tasks. Also from this, the influence on the control can be suppressed.

  In addition, when the CPU 5 determines that there is no longer a possibility of the task missing of the periodic task after shifting to the simple logic mode (S240: YES), the execution mode of the periodic task is switched from the simple logic mode to the normal logic mode. (S250). For this reason, it is possible to return to the normal mode.

  In S240 of FIG. 4, it is determined whether or not the margin time calculated in S110 of FIG. 3 is equal to or greater than a predetermined value. If the margin time is equal to or greater than the predetermined value, there is no possibility of task omission. The determination may be made to proceed to S250.

As mentioned above, although embodiment of this invention was described, this invention can take a various form, without being limited to the said embodiment. The above-mentioned numerical values are also examples, and other values may be used.
For example, in S200 of FIG. 3, information indicating the simple logic function last executed in the current periodic task is stored in the RAM 9, and in the next periodic task, the simple logic in the next order of the simple logic function indicated by the information is stored. It may be executed from a function. Further, the control target may be a transmission or the like.

  In addition, the functions of one component in the above embodiment may be distributed as a plurality of components, or the functions of a plurality of components may be integrated into one component. Further, at least a part of the configuration of the above embodiment may be replaced with a known configuration having the same function. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, all the aspects included in the technical idea specified by the wording described in the claims are embodiments of the present invention. In addition to the electronic control unit (ECU) described above, a system including the electronic control unit as a constituent element, a program for causing a computer to function as the electronic control unit, a medium storing the program, a task omission prevention method, etc. The present invention can also be realized in various forms.

  1 ... ECU (electronic control unit), 5 ... CPU, 7 ... ROM

Claims (6)

An electronic control device (7) that includes a storage unit (7) that stores a task to be executed at regular intervals to control a control target, and a processing unit (5) that executes the task at regular intervals. In 1)
As the plurality of functions constituting the task, a first type logic function that is a logic function that cannot be simplified, and a second type logic function that is a logic function that has little influence on the control of the control target even if simplified. There is,
The storage means stores, as the second type logic function, a normal logic function for a normal operation that is not simplified and a simple logic function for a calculation that is simplified more than the normal operation. And
The execution mode when the processing means executes the task includes a normal logic mode (S150) in which the normal logic function is executed as the second type logic function, and the simple logic as the second type logic function. There is a simple logic mode (S160 to S200) for executing the function,
The processing means includes
A determination means (S110, S220) for determining whether or not there is a possibility that a task omission that cannot be performed at the predetermined time may occur;
Mode switching means (S230) for switching the execution mode from the normal logic mode to the simple logic mode when the determination means determines that the task omission may occur.
An electronic control device. The electronic control device according to claim 1.
When the execution of the task is started, the determination unit measures the time from the previous end of the task to the start of this time as a margin time, and if the measured margin time is less than a specified value, Determining that the task omission may occur,
An electronic control device. The electronic control device according to claim 1 or 2,
There are a plurality of the second type logic functions, and the storage unit stores the normal logic function and the simple logic function for each of the plurality of the second type logic functions.
The processing means includes
In the task, the first type logic function is executed before the second type logic function (S120),
Further, in the task in the simple logic mode, as much as possible within a range in which the task can be completed by the next scheduled start time of the task after the execution of the first type logic function is completed. Executing the simple logic function (S160 to S200);
An electronic control device. The electronic control device according to claim 3.
In the task in the case of the simple logic mode, the processing means executes the simple logic functions in order from the smallest processing time,
An electronic control device. The electronic control device according to claim 4.
In the task in the case of the simple logic mode, the processing means may not execute all the simple logic functions (S170: NO), and the next task is the previous task. Executing from the simple logic function in the next order of the simple logic function executed last (S200, S160, S180),
An electronic control device. The electronic control device according to any one of claims 1 to 5,
The processing means includes
After the execution mode is switched from the normal logic mode to the simple logic mode, a return determination unit (S240) for determining whether or not the possibility of the task omission occurs is eliminated.
Mode return means (S250) for switching the execution mode from the simple logic mode to the normal logic mode when it is determined by the return determination means that there is no possibility that the task omission occurs.
An electronic control device.