JP5040710B2 - Electronic control device and calculation method in electronic control device - Google Patents

Description

  The present invention relates to an electronic control device that controls each part of a vehicle, and also relates to a calculation method in a control process in the electronic control device.

  2. Description of the Related Art Conventionally, various electronic control devices (hereinafter referred to as ECUs) are mounted on a vehicle according to functions. For example, there are various types such as an engine ECU for controlling the engine and a brake ECU for controlling the brake. Each of these ECUs incorporates dedicated software (see, for example, Patent Document 1).

  In the process of developing an ECU and embedded software incorporated in the ECU, the range of values that can be handled (hereinafter referred to as the data range) is changed to control requirements (for example, fuel injection amount, torque, engine speed, etc.). In many cases, the data type (memory size) of the memory for storing the data is predicted in advance, and the data accuracy according to the data range and data type is determined and designed. In order to effectively use limited resources, a data range is predicted in advance, and an optimal data type and data accuracy are determined (designed) according to the predicted data range.

  Data types (memory size) include 2 bytes and 4 bytes. For example, when a value of 1 to 10 (data range is 1 to 10) is represented by a 2-byte data type, the resolution (data accuracy) is 10/65535 (2 bytes). When data with a data range of 1-1000 is represented by a 2-byte data type, the resolution (data accuracy) is 1000/65535 (2 bytes). Other data types include, for example, an integer type that handles integers and a real number type that handles real numbers. Examples of the integer type include a signed integer type indicating positive / negative and an unsigned integer type including only positive numbers, and examples of the real number type include a floating point type and a fixed point type.

And in the embedded software in ECU, a calculation is performed using the data type and data accuracy which were determined beforehand.
JP 59-85444 A

  By the way, in the development process as described above, a change may occur in the data range determined according to the control requirements. When the data range changes, the data type and data accuracy determined according to the data range need to be reviewed. In other words, it is necessary to redesign the embedded software.

  Although it is conceivable to estimate the data range with a margin in advance, if the data range is large, if the value is expressed with a limited data type (memory size), the resolution of the memory (LSB) ) Is inevitably rough. That is, if the data range is set large, the data accuracy is lowered and the error is increased. On the other hand, increasing the memory size increases the cost.

  In terms of the increase in cost due to the increase in memory size, there is a problem from the following viewpoint. In recent years, floating-point arithmetic has been introduced as the performance of microcomputers has improved. However, in floating-point arithmetic, resources (memory size) are uniform regardless of the data range determined from control requirements. It is determined (eg, 4 bytes) and may require more resources (memory size) than before. As a result, it may be necessary to increase the capacity of the memory in the microcomputer or increase the capacity of the nonvolatile memory (EEPROM), which leads to an increase in cost.

  The present invention has been made in view of these problems, and an object of the present invention is to improve as much as possible the accuracy of data handled in control processing for control in an electronic control device for a vehicle that controls each part of the vehicle. The object is to prevent software redesign and memory capacity increase in the apparatus.

  The electronic control device according to claim 1, which has been made to achieve the above object, is provided in a vehicle and executes a control process for controlling a control target in the vehicle. In the control processing program, the data type of the variable (for example, a type such as 2 bytes or 4 bytes) is predetermined (for example, declared in the program).

  In the electronic control device according to the first aspect, the data width acquisition means is numerical data detected for controlling the control object, and the width of the variable range of the numerical data handled in the control process (hereinafter, Information representing data width) is acquired, and the resolution calculation means calculates a resolution obtained by dividing the data width acquired by the data width acquisition means by a value representing a range that can be stored in the data type. In the control process, numerical data is stored in the memory with the resolution calculated by the resolution calculation means.

  That is, the resolution is calculated according to the data width of the numerical data. For example, if there is numerical data A whose variable range is 0 to 10 (data width is 10) and numerical data B whose variable range is 0 to 100 (data width is 100), if they are stored in the same data type In the case of the former, the resolution can be increased 10 times. Specifically, if the data type is 2 bytes, the resolution of the numerical data A is 10/65535, and the resolution of the numerical data B is 100/65535. In the electronic control device according to the first aspect of the present invention, since the resolution is set optimally (so that the resolution becomes higher) according to the data width of the numerical data, it is possible to prevent the data accuracy from becoming coarse. . In other words, the data accuracy is improved as much as possible.

Further, since the resolution (data accuracy) is calculated according to the data width, it is possible to flexibly cope with changes in the data width.
For example, in the past, at the design stage, the data width was predicted according to the control requirements and specifications, and the data type and resolution (data accuracy) were set according to the predicted data width. Are calculated (predicted) according to control requirements and specifications, and the calculated value (predicted value) of the data width may change. For this reason, the data type and resolution (data accuracy) may need to be reviewed. In other words, redesign may be necessary. In order to avoid such redesign, it is conceivable to estimate the data width to be large, but in this case, the resolution (data accuracy) becomes coarse.

  On the other hand, in the electronic control device according to the first aspect, since the resolution (data accuracy) is calculated according to the data width, the resolution (data accuracy) which has been a problem in the related art as described above is reviewed. Such work becomes unnecessary. That is, the problem of redesign can be avoided. Further, it is possible to avoid the problem that the resolution (data accuracy) is lowered by estimating the data width to be large.

  Furthermore, according to the configuration of the first aspect, the versatility of the software can be improved. Specifically, for example, the data width varies depending on the type of vehicle or engine, but according to software whose resolution (data accuracy) is calculated according to the data width, what kind of electronic data is used regardless of the type of vehicle or engine. It can also be mounted on a control device. In addition, since the resolution (data accuracy) is calculated on the software, the resolution (data accuracy) is recognized on the software. Therefore, the program (calculation) is switched according to the resolution (data accuracy). It is no longer necessary. For example, in the conventional configuration in which the resolution (data accuracy) is set in advance, for example, the resolution (data accuracy) is defined in advance in the program. Therefore, it is necessary to switch the program for each resolution (data accuracy). According to the configuration of claim 1, such a need is eliminated.

Next, the electronic control device according to claim 1 may be configured as in claim 2.
According to a second aspect of the present invention, there is provided the electronic control device according to the first aspect, wherein the data width acquisition means divides the data width by a predetermined number of divisions, and the individual data widths after the division (hereinafter referred to as individual data widths) And a resolution calculation unit that calculates a resolution obtained by dividing the individual data width by a value representing a range that can be stored in the data type (hereinafter referred to as individual resolution). It has become.

  Then, the variable range is divided by a predetermined number of divisions, and for each of the divided areas (hereinafter referred to as individual areas), an offset value for calculating the starting value (hereinafter referred to as an offset value) of that area In the control process, a value obtained by subtracting an offset value (hereinafter referred to as a target offset value) of an individual area including the numerical data from the numerical data value is stored in the memory with the individual resolution. In addition, the numerical data is expressed using the value stored in the memory and the target offset value.

The configuration of the second aspect will be specifically described with an example.
Take numerical data A whose variable range is 0 to 10 (data width is 10) as an example. The number of divisions is 4 and the data type is 2 bytes.

  When the data width of the numerical data A is divided by the number of divisions 4 (that is, divided into four), the individual data width after division is 2.5. When the data width 2.5 is stored in a 2-byte data type, the resolution is 2.5 / 65535.

  The individual areas after dividing the variable range 0 to 10 by the division number 4 are 0 to 2.5 (area 0), 2.5 to 5.0 (area 1), and 5.0 to 7.5, respectively. (Region 2), 7.5 to 10 (region 3). The starting value (offset value) of each region is 0, 2.5, 5.0, and 7.5, respectively. The numerical value of the boundary between the regions belongs to the region with a large number. For example, a numerical value of 2.5 belongs to region 1.

  Here, a case where a numerical value of 3.5 is expressed is considered. The numerical value 3.5 is included in the region 1 among the individual regions after the variable range 0 to 10 is divided into four. 3.5 is 2.5 + 1, and is expressed as a numerical value obtained by adding 1 to the offset value 2.5 of the region 1.

  In the configuration of claim 2, 1 in the case of 3.5 = 2.5 + 1 is stored in the memory with a resolution of 2.5 / 65535. Then, the value stored in the memory and the numerical value of 2.5 which is the offset value represent a numerical value of 3.5.

  According to this, when a value of 3.5 is represented, the value can be represented with higher resolution (data accuracy). Specifically, the data width of the predetermined numerical data is divided by the predetermined number of divisions, and the resolution is calculated based on the data width after the division, so the resolution (data accuracy) is improved by (1 / number of divisions) times Can be made fine.

Next, the electronic control device according to claim 2 is preferably configured as in claim 3.
According to a third aspect of the present invention, in the electronic control device of the second aspect, the data width is divided into a predetermined number of divisions for each predetermined width, and the offset value is divided into individual data widths. It is calculated by multiplying the minimum value of the integer value representing the number of boundaries by the maximum value.

Regarding the number of division boundaries, for example, in the case of four divisions, the number of boundaries (number of divisions) is three.
For example, in the example in which the variable range 0 to 10 and the data range 10 of the numerical data A are divided into four, according to the configuration of the third aspect, the offset values 0, 2.5, 5.0, and 7.5 are bothered. Even if the data width is 2.5 and the information indicating the number of division boundaries (information indicating four divisions) is present, the data width 2.5 is multiplied by 0 to 3 to obtain the offset value. 0 (2.5 * 0), 2.5 (2.5 * 1), 5.0 (2.5 * 2), and 7.5 (2.5 * 3) can be calculated. In the case of four divisions, there are three division boundaries as described above, and the offset value is calculated by multiplying the data width 2.5 by an integer value of 0 to 3.

  By the way, in an electronic control device, numerical data may be stored in a non-volatile memory (hereinafter referred to as EEPROM) or backup RAM provided in the electronic control device. In this case, if the offset value is stored as it is, more memory capacity is required. In this regard, in the electronic control device according to the third aspect, as long as the information indicating the number of divisions is stored, it is not necessary to store the offset value as it is, so that the memory capacity can be saved.

  In addition, when 2 bits are allocated as a memory size for storing information representing the number of divisions, 0 to 3 (that is, information representing up to 4 divisions) can be stored in the memory. For this reason, for example, information representing up to four divisions can be stored for each of four types of numerical data in 1-byte data.

Next, the electronic control device according to claims 1 to 3 can be configured as in claim 4.
The electronic control device according to claim 4 includes operation control means for controlling operations of the data width acquisition means and the resolution calculation means, the operation control means for each type of numerical data based on a user input. It is determined whether or not the operation of the acquisition unit and the resolution calculation unit is permitted. When the operation is not permitted by the operation control unit, the data width acquisition unit and the resolution calculation unit are configured not to operate, and the control processing in this case In this case, numerical data is stored in the memory with a resolution input in advance by the user.

  For example, the configuration in which the resolution (data accuracy) is appropriately calculated according to the data width has the advantages as described above. On the other hand, the developer (designer) may want to fix the resolution (data accuracy). is assumed. In this regard, according to the electronic control device of claim 4, it is possible to invalidate the configuration in which the resolution (data accuracy) is calculated according to the data width, which is requested by the developer (designer). Can respond.

Next, according to a fifth aspect of the present invention, in the electronic control device according to the first to fourth aspects, the numerical data is stored in the memory as a fixed-point variable.
For example, in the case of a floating-point variable, the data type is at least 4 bytes, and it may be necessary to increase the memory capacity. On the other hand, in the electronic control device according to the fifth aspect, since the fixed decimal type is applied, the memory capacity can be suppressed as compared with the case where the floating decimal type is applied.

  Depending on the type of numerical data, whether to apply a floating decimal type or a fixed decimal type may be changed. For example, a floating-point type is applied to numerical data that requires precision in resolution (data accuracy), and a fixed decimal type is applied to numerical data that does not require much precision in resolution (data accuracy). You may make it.

Next, an electronic control device according to a fifth aspect is preferably configured as in the sixth aspect.
According to a sixth aspect of the present invention, in the electronic control device of the fifth aspect, the required accuracy of the numerical data is predetermined, and the numerical data is stored in the memory with a resolution calculated by the resolution calculating means as a fixed-point variable. Comparing means for comparing the accuracy of the stored data (hereinafter referred to as numerical data accuracy) with the required accuracy is provided. Whether the numerical data accuracy satisfies the required accuracy based on the comparison result of the comparing means Is satisfied, the numerical data is stored in the memory as a fixed decimal variable.

  According to this, when the numerical data is stored in the memory in the fixed decimal type, if the resolution (data accuracy) calculated according to the data width by the resolution calculation means satisfies the predetermined required accuracy. In this case, the memory capacity can be saved. Conversely, if the resolution (data accuracy) calculated according to the data width by the resolution calculation means does not satisfy the predetermined required accuracy, it can be prevented from being stored in the fixed decimal type. In this case, for example, the accuracy of numerical data can be improved by storing the data in a floating-point type.

That is, according to the configuration of the sixth aspect, it is possible to achieve both saving of memory capacity and preventing deterioration of data accuracy.
Next, an electronic control device according to a seventh aspect of the present invention is an electronic control device that is provided in a vehicle and executes a control process for controlling a control target in the vehicle, and a data type of a variable is determined in advance in the control process program. The resolution that is the numerical data detected for controlling the controlled object and is the required accuracy of the numerical data to be handled in the control process is determined in advance.

  The data width acquisition means acquires information indicating the width of the variable range of the numerical data (hereinafter referred to as data width), and the division number calculation means can store the data width in the data type with the resolution. Divide by the value representing the range, round up the result to calculate the number of divisions, and the offset value calculation means calculates the number of divisions in which the variable range of the numerical data is calculated by the division number calculation means (hereinafter calculated division) For each of the individual regions (hereinafter referred to as individual regions) after being divided by a number), the starting value (hereinafter referred to as an offset value) of that region is calculated.

  In the control process, a value obtained by subtracting an offset value (hereinafter referred to as a target offset value) of an individual area including the numerical data from the value of the numerical data is stored in the memory with a predetermined resolution. In addition, the numerical data is represented using the value stored in the memory and the target offset value.

  8. The electronic control unit according to claim 7, wherein the variable range (data width) of the numerical data is divided, and the width stored in the memory is narrowed to the data width after the division, so that the resolution of the data (data accuracy) which is required accuracy There is a purpose of satisfying. It differs from claim 2 in the following points.

  In the electronic control device of claim 7, the required accuracy of numerical data is predetermined, and the number of divisions of the variable range (data width) of the numerical data is calculated in accordance with the required accuracy. This is different from the configuration of 2.

  For example, in an electronic control device, the precision of resolution (data accuracy) may be determined based on control requirements or specifications, but if the data width is large, if the resolution (data accuracy) is to be maintained, the data You have to make the mold bigger.

  In this regard, according to the electronic control device of the present invention, the division number calculating means converts the data width acquired by the data width acquiring means into a predetermined data type with a predetermined resolution (both are predetermined in advance). In order to calculate the number of divisions by dividing by the value representing the storable range and rounding up the result, the variable storage range (data width) of the numerical data is divided by the number of divisions. Since the resolution (data accuracy) when narrowed to the individual data width later matches the predetermined required accuracy, the required accuracy can be satisfied without increasing the data type.

Next, an electronic control device according to a seventh aspect may be configured as in the eighth aspect.
An electronic control device according to an eighth aspect of the present invention is the electronic control device according to the seventh aspect, further comprising operation control means for controlling operations of the data width acquisition means and the division number calculation means, and the operation control means is based on a user input. Then, for each type of numerical data, it is determined whether or not the operation of the data width acquisition unit and the division number calculation unit is permitted, and when the operation is not permitted by the operation control unit, the data width acquisition unit and the division number calculation unit In the control process in this case, the numerical data is stored in the memory with the resolution input in advance by the user.

According to this, the same effect as described in claim 4 can be obtained.
Next, the invention of claim 9 is an arithmetic method used in a control process for controlling an object to be controlled in the vehicle by an electronic control device provided in the vehicle, wherein the data type of the variable is set in advance in the program of the control process. Information that is defined and detected to control the control target, and that represents the width of the variable range of the numerical data (hereinafter referred to as data width) handled in the control process, A resolution obtained by dividing the data width by a value representing a range that can be stored in the data type is calculated, and in the control process, numerical data is stored in the memory with the calculated resolution. It is the calculation method in a control apparatus.

  According to this, the same effect as described in claim 1 can be obtained.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a configuration diagram of an electronic control device (hereinafter referred to as ECU) 1 to which the present invention is applied.

  The ECU 1 of FIG. 1 is provided in a vehicle and controls each part of the vehicle. From the range (data range described later) that can be taken by various control data values handled by the ECU 1, It has a function of dynamically calculating the resolution (LSB: Last Significant Bit) of a memory for storing control data. In other words, the data accuracy of the control data is dynamically calculated according to the data range for each control data, instead of handling the data accuracy uniformly. The control data is used in various control processes (control logic) for controlling the vehicle. For example, data such as the fuel injection amount and the engine speed can be considered.

The ECU 1 includes a microcomputer 10 and an EEPROM 30 that is a nonvolatile memory.
The microcomputer 10 operates in accordance with a predetermined program to execute various calculations, a flash ROM 16 in which programs for causing the CPU 12 to execute various calculations and fixed data are stored in advance, and calculation results by the CPU 12 are temporarily stored. And a backup RAM 20 that is always supplied with a power supply voltage from, for example, a battery (not shown) provided in the vehicle and can hold information while the power supply voltage is supplied.

The CPU 12 also includes an FPU 14 that performs floating-point arithmetic. The FPU 14 is an arithmetic unit that operates according to a command from the CPU 12 and performs floating-point arithmetic.
Next, the processes of FIGS. 2 to 4 executed by the CPU 12 of the ECU 1 will be described.

  First, FIG. 2 is a flowchart showing a resolution calculation process for calculating data accuracy (memory resolution) of control data. This resolution calculation process is executed at a timing when the control data is updated or referred to.

  In the resolution calculation process of FIG. 2, first, in S110, information representing a data range (hereinafter also referred to as Ds (also described as Ds)) that is a range (width) of values that can be taken by the control data is acquired. In the following description, description of “information representing” is omitted as appropriate, for example, “acquire data range (Ds)”. The data range (Ds) specifically refers to the width of the range of the minimum value to the maximum value of the control data. The data range (Ds) is stored in advance in the flash ROM 16, and the data range (Ds) is read from the flash ROM 16 and acquired in S110. The data range (Ds) is determined according to control requirements (for example, various requirements such as fuel injection amount, torque, and engine speed), and the flash ROM 16 includes a data range (Ds) and control requirements. Information (table) representing the relationship is stored. In S110, information on the data range (Ds) corresponding to the control requirements at that time is read.

  After S110, the process proceeds to S120, and the type (size) of the memory storing the control data is acquired (read). In other words, the memory type is a variable type (for example, a type such as 2 bytes or 4 bytes). In the following, the memory type (size) is also described (also shown) as Dsp. Information indicating the memory type (Dsp) is stored in advance in the flash ROM 16, for example.

  Next, in S130, the resolution of the memory (hereinafter also referred to as Vac (also described)) is updated (calculated). Specifically, the resolution (Vac) of the memory is calculated by the equation Vac = Ds / Ds_max. Ds_max is the maximum value of the memory type (Dsp). That is, the resolution (Vac) of the memory is a value obtained by dividing the data range (Ds) by the range (Dsp) that can be stored in the memory type. For example, when storing control data in the data range 10 (minimum value 0 to maximum value 10) in a 2-byte type, the resolution is 10/65535. After S130, the process ends.

  Next, FIG. 3 is a flowchart showing a storage process in which actual data calculated by various control logics is converted using the memory resolution (Vac) calculated in the process of FIG. 2 and stored in the memory. Here, the actual data (tDfx) is a temporary variable that is temporarily used in the program (stored temporarily in a register or the like), for example, and the control data (Dfx) has a storage address defined therein. Distinguish it as a variable exposed to control logic.

In the storage process of FIG. 3, first, predetermined actual data (hereinafter also referred to as tDfx (also described)) is calculated in S210.
In step S220, the actual data (tDfx) is converted into data that matches the resolution (Vac) of the memory calculated in advance in step S130, and the converted data is written in the memory. Data written in the memory is control data (Dfx), which can be used in various control logics.

  The control data (Dfx) is calculated by the equation Dfx = tDfx / Vac. That is, in S220, the actual data (tDfx) is stored in the memory as data (control data: Dfx) that matches the resolution (Vac) of the memory calculated in advance on the software. After the process of S220, the process ends.

  Next, FIG. 4 is a flowchart showing a conversion process for converting the control data (Dfx) stored in the memory into actual data (tDfx) that can be used in various control logic programs.

In this conversion process, first, in S310, the control data (Dfx) stored in the memory in S220 described above is read from the memory.
Next, proceeding to S320, actual data (tDfx) is calculated. Specifically, the actual data (tDfx) is calculated by the equation tDfx = Dfx * Vac.

In S330, processing (control logic) using actual data (tDfx) is executed. Thereafter, the process is terminated.
As described above, in the ECU 1 of the first embodiment, the resolution (data) of the memory is determined from the data range that is the range (width) of values that the control data can take and the type (size) of the memory that stores the control data. Accuracy) is calculated on the software. As a result, regardless of the size of the data range, appropriate data accuracy is set on the software according to the data range. For example, when the data range is small, the data accuracy is set high, so that even finer digits are expressed, and conversely, when the data range is large, the data accuracy is set small, thereby making the fine data Even if it cannot be expressed up to digits, a wider range of values can be expressed.

  In this way, since the data accuracy is calculated on the software, the data accuracy can be recognized on the software and the calculation can be executed. Conventionally, for example, when there are a plurality of types of data accuracy, there is a case in which a configuration in which computation on software is switched in accordance with the data accuracy may be provided, but the ECU 1 of the present embodiment recognizes the data accuracy. Therefore, such a configuration is not necessary. This increases the versatility of the software.

  Further, in the development of the embedded software installed in the ECU 1, it is possible to avoid the problem that the data accuracy needs to be reviewed (redesigned) due to a change in the data range predicted according to the control requirements and specifications. .

In this embodiment, the process of S110 corresponds to a data width acquisition unit, and the process of S130 corresponds to a resolution calculation unit.
[Second Embodiment]
Next, the second embodiment will be described focusing on differences from the first embodiment.

The second embodiment is different from the first embodiment in that the CPU 12 executes the processes of FIGS. 5 to 7 instead of the processes of FIGS.
FIG. 5 shows a calculation for calculating the range of each divided area according to the data range (Ds) and the number of divisions of the data range (Ds), and calculating the resolution of the memory according to the calculated range. It is a flowchart showing a process.

  In the process of FIG. 5, first, in S410, the data range (Ds) and the number of divisions of the data range (Ds) (hereinafter referred to as Ndiv (also described)) are acquired. Here, the data range (Ds) and the division number (Ndiv) are stored in the flash ROM 16 in advance, and in S410, the data range (Ds) and the division number (Ndiv) are read from the flash ROM 16 and acquired. The division number (Ndiv) is determined for each data type, for example.

  In step S420, the data range (Ds) is equally divided by the number of divisions (Ndiv), and the data range of the divided area (hereinafter also referred to as Dsd (also described)) is calculated. The data range (Dsd) represents the width of each area after the division, and is calculated by the equation Dsd = Ds / Ndiv.

  Next, proceeding to S430, an offset value (Dofn) is calculated. Here, the offset value (Dofn) is the starting value of each area after the variable range of the minimum value to the maximum value of the data is divided by the division number (Ndiv), and the value of the data range (Dsd) is 0. It is calculated by multiplying the value of ~ n (n = 0 to Ndiv-1). That is, the offset value (Dofn) is calculated by the equation Dofn = Dsd * n. The calculated offset value (Dofn) is stored in a predetermined memory.

The data range (Dsd) and the offset value (Dofn) will be described with examples.
For example, when the data range (Ds) is 10 (minimum value 0 to maximum value 10) and the division number (Ndiv) is 4 (that is, when the data range 10 is divided into 4), the data range of each divided area (Dsd) is 10 (data range: Ds) / 4 (number of divisions: Ndiv) = 2.5 (data range: Dsd). The offset values (Dofn) are 2.5 * 0 = 0, 2.5 * 1 = 2.5, 2.5 * 2 = 5, 2.5 * 3 = 7.5.

  In step S440, the resolution (Vac) of the memory is calculated. The resolution (Vac) of the memory is calculated by the equation Vac = Dsd / Ds_max. That is, here, the resolution (Vac) of the memory is calculated according to the data range (Dsd) of the area after the data range (Ds) is divided by the division number (Ndiv). Specifically, the resolution when the width stored in the memory is the data range (Dsd) is calculated. According to this, the resolution (Vac) of the memory is improved as compared with the case of calculating in accordance with the data range (Ds) before the division, but this is because the data stored by narrowing the data range stored in the memory. The purpose is to improve the data accuracy. As will be described in detail later, the control data can be expressed (restored) using the value in the data range (Dsd) after the division and the above-described offset value.

  Next, FIG. 6 is a flowchart showing a storage process in which actual data calculated by various control logics is converted using the memory resolution (Vac) calculated in the process of FIG. 5 and stored in the memory.

In this storage process, first, predetermined actual data (tDfx) is calculated in S510.
Next, proceeding to S520, an offset value (Dofn) is calculated. This process is the same as the process of S430 described above, and is calculated by an expression of Dofn = Dsd * n (n = 0 to Ndiv-1).

  In step S530, the real data (tDfx) is divided into the number of divisions (Ndiv) in the variable range from the minimum value to the maximum value of the actual data (tDfx). Calculate whether it is included. The purpose is to calculate the value of n of the offset value (Dofn) (to calculate a specific value of Dofn). This is why “calculation of n” is described in S530. For example, when the value of the actual data (tDfx) is compared with the offset value calculated in S520, if Dof2 ≦ tDfx <Dof3, n = 2. Details will be described later with reference to FIG.

  In step S540, the actual data (tDfx) is converted into data that matches the resolution (Vac) of the memory calculated in advance in step S440, and the converted data is written in the memory. As described above, the data written in the memory is control data (Dfx) that can be used by various control logics. Here, the control data (Dfx) is calculated by an expression of Dfx = (tDfx−Dofn) / Vac. That is, a value obtained by subtracting the offset value (Dofn) from the actual data (tDfx) is calculated using the resolution of the memory (in other words, the data accuracy) calculated according to the data range (Dsd) of the divided area. According to this, while the data accuracy of the converted data is improved, the original data can be correctly calculated (restored) using the converted data and the offset value (Dofn).

  Next, FIG. 7 is a flowchart showing a conversion process for converting the control data (Dfx) stored in the memory into actual data (tDfx) that can be used in programs of various control logics.

In this conversion process, first, in S610, the control data (Dfx) stored in the memory in S540 is read from the memory.
Next, proceeding to S620, actual data (tDfx) is calculated. Specifically, the actual data (tDfx) is calculated by the equation tDfx = Dfx * Vac + Dofn.

In S630, processing (control logic) using actual data (tDfx) is executed. Thereafter, the process is terminated.
Next, the operation of the second embodiment will be described with reference to FIG.

In the graph of FIG. 8, the vertical axis indicates the data value, and the horizontal axis indicates the number of divisions.
In FIG. 8, the width of the data values Vmin to Vmax is the data range (Ds).
In the second embodiment, the data range (Ds) is equally divided by the division number (Ndiv). The range (width) of each area after equally dividing the data range (Ds) by the number of divisions (Ndiv) is the data range (Dsd). Of the divided areas, the 0th area corresponds to Vmin (or offset value Dof0) to Dof1, and the first area corresponds to Dof1 (offset value of the first area) to Dof2. This area corresponds to Dof2 (offset value of the second area) to Dof3. Hereinafter, the same applies to the nth. The values of the offset values Dof0, Dof1, Dof2, Dof3,... Dofn are calculated by the formula Dofn = Dsd * n (n = 0 to Ndiv-1) as described above and stored in a predetermined memory. .

Assume that actual data (tDfx) is calculated (S510). Then, it is assumed that the value of the actual data (tDfx) is included in the second area (Dof2 to Dof3).
In this case, it is calculated that Dof2 ≦ tDfx <Dof3, and n = 2 (actual data: tDfx is included in the second region) (S530).

  At this time, the resolution (Vac) of the memory for storing the actual data (tDfx) is calculated by the equation Vac = Dsd / Ds_max as described above (S440). The data range (Dsd) is the width of the range of Dof2 to Dof3. That is, since the data stored in the memory only needs to represent the data range (Dsd: Dof2 to Dof3), not the data range (Ds), a finer digit can be expressed. For this reason, data accuracy is improved.

  On the other hand, since the offset value (Dof2) of the area including the value of the actual data (tDfx) is separately calculated, the actual value (tDfx) is calculated from the offset value (Dof2) and the high resolution value stored in the memory. ) Is represented correctly.

  Here, an application example (application example) of the second embodiment will be described taking post-processing control in a vehicle as an example. More specifically, the post-processing control is, for example, when particulate matter (PM) contained in the exhaust gas of a diesel engine is captured by a diesel particulate filter (DPF), and when the captured PM reaches a predetermined amount. The control is such that the temperature of the DPF is raised, PM is burned by the reaction of the catalyst supported on the DPF, and the DPF to which the PM is attached is regenerated.

  In such post-processing control, the PM amount generated in one cycle of the diesel engine is calculated, and the calculated values are integrated. The integrated value is the amount of PM deposited on the DPF. The integrated value is stored (updated and stored) in the backup RAM 20 or the EEPROM 30. By the way, the amount of PM generated per cycle is very small, but the value increases as it is integrated. For this reason, the structure which can memorize | store the value of PM amount in high resolution and wide range is needed. Conventionally, there is a case where the capacity of the backup RAM 20 or the EEPROM 30 is increased.

  On the other hand, according to the configuration of the second embodiment, by dividing the data range and narrowing the width of the value stored in the memory (backup RAM 20 or EEPROM 30) to the width of each divided area, The resolution can be improved and a wide range of numerical values can be stored by separately holding the starting value (offset value) of each region. As a result, a desired value can be stored in a wide range over a wide range without increasing the memory capacity.

In the present embodiment, the process of S420 corresponds to the individual data width calculation unit, and the process of S430 corresponds to the offset value calculation unit.
[Third Embodiment]
Next, the third embodiment will be described with a focus on differences from the second embodiment compared to the second embodiment.

The third embodiment is different from the second embodiment in that floating point arithmetic is executed by the control logic, whereby floating point type data is calculated.
Then, the CPU 12 executes a process of converting the floating point type data into fixed decimal type data.

  Specifically, in the third embodiment, as compared with the second embodiment, the CPU 12 executes the process of FIG. 9 instead of the storage process of FIG. The process of FIG. 9 is executed at a timing at which control data is updated or referenced.

In the process of FIG. 9, first, in S710, predetermined floating-point actual data (tDfl) is calculated.
Next, proceeding to S720, an offset value (Dofn) is calculated. The process of S720 is the same as the process of S520 of FIG.

  Next, the process proceeds to S730, and it is calculated in which area the actual data (tDfl) is included in the divided area obtained by equally dividing the data range (Ds) by the division number (Ndiv). The purpose is to calculate the value of n of the offset value (Dofn) (to calculate a specific value of Dofn). This is why “calculation of n” is described in S730. For example, when the value of the actual data (tDfl) is compared with the offset value calculated in S720, if Dof2 ≦ tDfl <Dof3, n = 2.

  In step S740, the actual data (tDfl) is converted into data that matches the memory resolution (Vac) calculated in advance in step S440, and the converted data is written in the memory. As described above, the data written in the memory is control data (Dfx) that can be used by various control logics. The control data (Dfx) is calculated by the equation Dfx = (tDfl−Dofn) / Vac. After S740, the process ends.

As described above, in the third embodiment, the calculation by the control logic is executed in the floating-point type to ensure the accuracy, and the calculated floating-point type data is converted into the fixed-point type and stored in the memory. Thus, the memory capacity is saved. For example, 4 bytes are required to store single-precision floating-point data, but if converted to fixed-decimal data, only 2 bytes are required. For this reason, memory capacity can be saved.
<Modification 1>
By the way, in the said 3rd Embodiment, you may comprise like the modification 1 shown below.

  FIG. 10 is a diagram for explaining the contents of the first modification. Specifically, FIG. 10 shows the control data (Dfx) calculated in the process of S740 in FIG. 9 and the value of n calculated in the process of S730 (offset value: the value of n in Dofn) in the EEPROM 30 (FIG. It is drawing which shows the method to memorize | store in 1).

  First, FIG. 10A will be described. The actual data (tDfl1, tDfl2) calculated in S710 described above is converted into control data (Dfx1, Dfx2) that is fixed decimal type data (S740). In addition, the value of n representing which area contains the control data (Dfx1, Dfx2) among the individual areas after dividing the variable range of the minimum value to the maximum value of the control data (Dfx1, Dfx2). (N1, n2) are respectively calculated (S730).

  Then, as shown in FIG. 10B, the calculated values of n (n1, n2) are converted into bit values and stored in the EEPROM 30. Regarding the point of storing the value (n1, n2) of n, this means that the value (n1, n2) of n is stored instead of storing the offset value (Dofn). More specifically, if the offset value (Dofn) is stored for each of n = 0 to Ndiv-1, a large memory capacity is required. Therefore, only the value of n is stored, and the offset value is calculated from the value of n. A specific value of (Dofn) can be calculated.

  For example, in a predetermined 16-bit memory area, the first 1 and 2 bits are allocated for storing n1, and the next 3 and 4 bits are allocated for storing n2. The same applies hereinafter. The last 15th and 16th bits are allocated for storing n8. If 2 bits are allocated as a memory area for storing the value of n as in the example of FIG. 10B, 0 to 3 can be expressed as the value of n.

According to the first modification, the memory capacity can be reduced as compared with the case where the offset value (Dofn) is stored for each of n = 0 to Ndiv-1.
For example, as shown in FIG. 10C, the data range (Ds) is 10 (minimum value 0 to maximum value 10), the division number (Ndiv) is 4 (that is, 4 divisions), the memory type is 2 bytes, The case where the value of the control data (tDfl) is 3.5 will be described as an example.

  The divided data range (Dsd) is 10 (data range: Ds) / 4 (number of divisions: Ndiv) = 2.5. The resolution (Vac) is 2.5 (data range: Dsd) / 65535 (2 bytes).

  In addition, the areas after dividing the area of the minimum value 0 to the maximum value 10 into four are 0 to 2.5 (area 0: n = 0) and 2.5 to 5.0 (area 1: n = 1), respectively. ), 5.0 to 7.5 (region 2: n = 2), and 7.5 to 10 (region 3: n = 3). The value 3.5 of the control data (tDfl) is included in the region 1 (that is, n = 1).

  In this case, in the first modification, 1 which is the value of n is converted into a bit value and stored. According to this, since the offset value (2.5) can be calculated by 2.5 (data range: Dsd) * 1 without storing the offset value (2.5), the offset value is stored. Compared to the case, the memory capacity can be saved.

On the other hand, 3.5 (actual data: tDfl) −2.5 (offset value: Dof1) = 1 is stored in the memory for control data (Dfx), but the resolution (Vac) is used. When converted, 1 / (2.5 / 65535) = 26214. In the case of hexadecimal display, it is 0x6666. That is, Dfx is represented by 0x6666, and this data is stored in the memory. Note that “0x” of 0x6666 is a code indicating that the display is hexadecimal. In calculating the actual data (tDfl) used in the control logic program, the actual data (tDfl) = 3.5 (10) from 1 (decimal number) represented by ˜0x6666 and the offset value 2.5 (decimal number). Decimal).
[Fourth Embodiment]
Next, the fourth embodiment will be described focusing on differences from the third embodiment compared to the third embodiment.

  Compared to the third embodiment, the fourth embodiment has a predetermined accuracy (required accuracy) required for data, and the number of divisions (Ndiv) of the data range (Ds) is not predetermined. The difference is that the division number (Ndiv) and the offset value (Dofn) are calculated according to the data range (Ds) so as to satisfy the required accuracy.

  Specifically, in the fourth embodiment, as compared with the third embodiment, the CPU 12 executes the process of FIG. 11 instead of the process of FIG. The process of FIG. 11 is executed at a timing when the control data is updated or referenced.

In the process of FIG. 11, first, floating-point actual data (tDfl) is calculated in S810.
In step S820, a predetermined memory type (Dsp) and resolution (Vac) are acquired. Information indicating the memory type (Dsp) and the resolution (Vac) of the memory is stored in advance in a predetermined memory, and the information is read out in S820.

  In step S830, the data range (Ds) of the actual data (tDfl) is calculated. The data range (Ds) is calculated by the formula of maximum value-minimum value of actual data (tDfl). This data range (Ds) is calculated on software based on various control requirements. That is, it changes according to control requirements.

  In step S840, the number of divisions (Ndiv) of the data range (Ds) is calculated. Specifically, the division number (Ndiv) is calculated so that the resolution when the range (width) of each divided data is stored in the memory satisfies the resolution (Vac) acquired in S820. The number of divisions (Ndiv) is calculated by the equation: Number of divisions (Ndiv) = tData / Ds_max. Here, tData = Ds / Vac. In calculating the number of divisions (Ndiv), the numbers after the decimal point are rounded up.

  Next, proceeding to S850, an offset value (Dofn) is calculated. Specifically, the offset value (Dofn) is calculated by an expression of offset value (Dofn) = data range (Dsd) * n (n = 0 to Ndiv−1). Dsd = tData / Ndiv.

  Next, proceeding to S860, control data (Dfx) is calculated. Specifically, the control data (Dfx) is calculated by the equation Dfx = (tDfl−Dofj) / Vac. The value of j of Dofj is calculated based on the formula of Dofj ≦ tDfl <Dofj + 1. That is, the value of j is calculated so as to satisfy Dofj ≦ tDfl <Dofj + 1.

In the fourth embodiment, the process of S840 corresponds to the division number calculating means.
<Modification 2>
By the way, in the said 2nd-4th embodiment, you may comprise like the modification 2 shown below. FIG. 12 is a diagram illustrating the contents of Modification 2. Specifically, in the second modification shown in FIG. 12, it is managed whether the resolution (Vac) of the memory and the offset value (Dofn) are dynamically calculated on software. In other words, it manages whether to enable or disable the configuration for dynamically calculating the resolution (Vac) and offset value (Dofn) of the memory on the software.

  For example, in the example of FIG. 12, management is performed using 2-bit data (that is, a numerical value of 0 to 3). The 2-bit management information is held for each data type. Specifically, in the example of FIG. 12, eight types of 2-bit management information are stored in 2-byte data. That is, 2-bit management information is assigned to each of the eight types of data.

  In the example of FIG. 12, 0 represents application among the numerical values of 0 to 3 represented by 2-bit data. Specifically, in the case of “apply”, the resolution (Vac) and offset value (Dofn) of the memory are dynamically calculated on the software. For example, this corresponds to the realization of the second embodiment or the third embodiment, and more specifically, this corresponds to the processing of S430 and S440 of the second embodiment being executed.

On the other hand, in the example of FIG.
Among these, 1 represents an example in which the resolution (Vac) is fixed to 160/256 and the offset value (Dofn) is fixed to 0. 2 represents an example in which the resolution (Vac) is fixed to 200/256 and the offset value (Dofn) is fixed to 10. 3 represents an example in which the resolution (Vac) is fixed to −1 and the offset value (Dofn) is fixed to 1. This corresponds to, for example, realizing the fourth embodiment in which the resolution (Vac) is predetermined.

According to the second modification, it is possible to easily enable or disable the configuration in which the resolution (Vac) or offset value (Dofn) of the memory is dynamically calculated on the software. Therefore, the degree of freedom is expanded. For example, it is possible to easily respond to a request from a developer (designer) who wants to fix the resolution (Vac).
<Modification 3>
Next, in the first to fourth embodiments, whether to apply the fixed decimal type or the floating decimal type as the type of the control data (Dfx) may be determined as follows.

Specifically, the CPU 12 executes the processing of FIG. 13 to determine whether to adopt the fixed decimal type or the floating decimal type.
In the process of FIG. 13, first, in S910, the memory type (Dsp) and the memory resolution (Vac) are acquired. The resolution (Vac) of the memory is calculated in S130 or S440 described above.

  Then, the process proceeds to S920, and whether or not the resolution (Vac) of the memory acquired in S910 is equal to or lower than the resolution (Vacmin) required in advance (in other words, whether the resolution is high or the resolution is excellent). Or not).

  If it is determined in S920 that Vac ≦ Vacmin (S920: YES), it is determined that the resolution (Vac) acquired in S910 is higher than the required resolution (Vacmin), the process proceeds to S930, and the fixed decimal type is applied. The purpose is to save the necessary memory capacity by applying the fixed decimal type. Thereafter, the process is terminated.

  On the other hand, if it is determined in S920 that Vac ≦ Vacmin does not hold, that is, Vac> Vacmin (S920: NO), it is determined that the resolution (Vac) acquired in S910 is inferior to the required resolution (Vacmin). Move to and apply floating point type. This is to prevent the resolution (data accuracy) of the control data (Dfx) from deteriorating from the required value. Thereafter, the process is terminated.

In this third modification, it is possible to achieve both saving of the memory capacity and preventing the resolution (data accuracy) from deteriorating from the required value.
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various form can be taken within the technical scope of this invention.

  For example, in the first embodiment, the resolution calculation process in FIG. 2 may be periodically executed. Note that, when periodically executed, the Vac calculated in the process of S130 needs to be held. That is, the calculated Vac needs to be stored in a predetermined memory area.

  In the resolution calculation process of FIG. 2, Vac may be updated (calculated) only when the data range changes. For example, in the process of FIG. 2, after acquiring Ds (data range) in S110, the CPU 12 determines whether or not the Ds (data range) has changed from the previous acquired value, and determines that it has changed. , Sac may be executed to update (calculate) Vac.

  In the resolution calculation process of FIG. 2, the minimum value (Vmin) and the maximum value (Vmax) that can be taken by the control data value are stored in the flash ROM 16 in advance, and in the process of S110, the CPU 12 determines the minimum value ( Vmin) and the maximum value (Vmax) are read from the flash ROM 16, and the data range (Ds) is calculated by executing the calculation of data range (Ds) = maximum value (Vmax) −minimum value (Vmin). Also good. The same applies to the calculation processing of FIG.

  Moreover, in the said modification 2, management information may be allocated for every group which grouped data into the bigger classification | category. Further, validity / invalidity may be managed for a configuration in which the division number (Ndiv) is dynamically calculated. In some cases, a configuration for dynamically calculating the memory type may be added. In this case, the configuration for dynamically calculating the memory type may be managed as valid / invalid. good.

It is a block diagram of ECU1 of this embodiment. It is a flowchart showing the resolution calculation process which CPU12 performs. It is a flowchart showing the storage process which CPU12 performs. It is a flowchart showing the conversion process which CPU12 performs. It is a flowchart showing the resolution calculation process which CPU12 of 2nd Embodiment performs (the 1). It is a flowchart showing the storage process which CPU12 of 2nd Embodiment performs (the 2). It is a flowchart showing the conversion process which CPU12 of 2nd Embodiment performs (the 3). It is drawing showing the effect | action of 2nd Embodiment. It is a flowchart showing the process which CPU12 of 3rd Embodiment performs. 10 is a diagram showing the contents of Modification 1. It is a flowchart showing the process which CPU12 of 4th Embodiment performs. 10 is a diagram showing the contents of Modification 2. 10 is a flowchart illustrating processing executed by a CPU 12 of Modification 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... ECU, 10 ... Microcomputer, 12 ... CPU, 14 ... FPU, 16 ... Flash ROM, 18 ... RAM, 20 ... Backup RAM, 30 ... EEPROM.

Claims (9)

An electronic control device that is provided in a vehicle and executes a control process for controlling a control target in the vehicle,
In the control processing program, the data type of the variable is predetermined,
Data width acquisition means for acquiring information indicating the width of a variable range of the numerical data (hereinafter referred to as data width) handled in the control process, which is numerical data detected for controlling the control object; ,
Resolution calculating means for calculating a resolution obtained by dividing the data width acquired by the data width acquiring means by a value representing a range that can be stored in the data type, and
In the control processing, the numerical data is stored in a memory with the resolution calculated by the resolution calculation means. The electronic control device according to claim 1.
The data width acquisition means includes
Individual data width calculation means for dividing the data width by a predetermined number of divisions and calculating individual data widths after the division (hereinafter referred to as individual data widths),
The resolution calculation means calculates the resolution obtained by dividing the individual data width by a value representing a range that can be stored in the data type (hereinafter referred to as individual resolution).
An offset value for dividing the variable range by the predetermined number of divisions and calculating a starting value (hereinafter referred to as an offset value) of each area after the division (hereinafter referred to as an individual area). A calculation means,
In the control process, a value obtained by subtracting an offset value (hereinafter referred to as a target offset value) of the individual area including the numerical data from the value of the numerical data is stored in the memory with the individual resolution. And an electronic control unit configured to represent the numerical data using a value stored in the memory and the target offset value. The electronic control device according to claim 2,
The data width is divided for each predetermined width by the predetermined number of divisions,
The electronic control device is characterized in that the offset value is calculated by multiplying the individual data width by a minimum value from a minimum value of integer values representing the number of division boundaries, respectively. The electronic control device according to any one of claims 1 to 3,
Operation control means for controlling the operations of the data width acquisition means and the resolution calculation means, the operation control means for each type of numerical data based on a user input, the data width acquisition means and the resolution calculation Determine whether to allow the action of the means,
When the operation is not permitted by the operation control unit, the data width acquisition unit and the resolution calculation unit are configured not to operate. In the control process in this case, the numerical data is input with a resolution input in advance by a user. Is configured to be stored in a memory. The electronic control device according to any one of claims 1 to 4,
The electronic control device is characterized in that the numerical data is stored in a memory as a fixed-point variable. The electronic control device according to claim 5.
The required accuracy of the numerical data is predetermined,
When the numerical data is stored as a fixed-point variable in the memory with the resolution calculated by the resolution calculation means, the accuracy of the data (hereinafter referred to as numerical data accuracy) is compared with the required accuracy. Comparing means to
Based on the comparison result of the comparison means, it is determined whether or not the numerical data accuracy satisfies the required accuracy, and if it satisfies, the numerical data is stored in a memory as a fixed decimal variable. An electronic control device characterized by that. An electronic control device that is provided in a vehicle and executes a control process for controlling a control target in the vehicle,
In the control processing program, the data type of the variable is predetermined,
The numerical data detected for controlling the control object, the resolution to be the required accuracy of the numerical data handled in the control process is determined in advance,
Data width acquisition means for acquiring information indicating the width of the variable range of the numerical data (hereinafter referred to as data width);
A division number calculating means for dividing the data width by a value representing a range that can be stored in the data type with the resolution and rounding up the decimal point of the result to calculate the division number;
For each of the individual areas (hereinafter referred to as individual areas) after the variable range of the numerical data is divided by the number of divisions calculated by the division number calculation means (hereinafter referred to as the calculated division number) Offset value calculating means for calculating a starting value (hereinafter referred to as an offset value) of
In the control process, a value obtained by subtracting an offset value (hereinafter referred to as a target offset value) of the individual area including the numerical data from the value of the numerical data is stored in the memory with the resolution. In addition, the electronic control device is configured such that the numerical data is represented using a value stored in the memory and the target offset value. The electronic control device according to claim 7.
And an operation control unit that controls operations of the data width acquisition unit and the division number calculation unit, and the operation control unit performs the data width acquisition unit and the division for each type of numerical data based on a user input. Determine whether to allow the operation of the number calculation means,
When the operation is not permitted by the operation control unit, the data width acquisition unit and the division number calculation unit are configured not to operate. In the control process in this case, the numerical value is input with a resolution input in advance by a user. An electronic control device configured to store data in a memory. An arithmetic method used in a control process for controlling a control target in a vehicle in an electronic control device provided in the vehicle,
In the control processing program, the data type of the variable is predetermined,
It is numerical data detected for controlling the control object, and obtains information indicating the width of the variable range of the numerical data handled in the control process (hereinafter referred to as data width),
Calculating a resolution obtained by dividing the acquired data width by a value representing a range that can be stored in the data type;
In the control process, the numerical data is stored in a memory with the calculated resolution.

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