JP3639615B2 - Electronic control unit - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an electronic control device such as an automobile control device, for example, having a microcomputer, at least one nonvolatile memory, and an input / output circuit, to which at least one sensor can be connected. .
[0002]
[Prior art]
For example, publicly known document-VDI Reports No. 612, 1986, pp. 361-373; “Self-Dianosis of Electronic Control Units in Motor Vehicles” byB. One control device is known from Przybyla-. The control device includes a microcomputer, a nonvolatile memory (EPROM), and a volatile memory (CMOS-RAM). Further, this control device is provided with an analog / digital converter and an output stage unit for outputting a control signal in order to detect a sensor signal from the connected sensor. The connected sensor is used for detecting operating parameters of the internal combustion engine, for example, intake air amount, engine speed, engine temperature, and the like.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to improve in view of the shortcomings of conventional devices. For example, when a control device is assembled, learning of a reference value characterizing the initial state of a system to be controlled is automatically performed. It is to provide an electronic control device as is done automatically.
[0004]
According to the present invention, the above problem is that at least one reference value is automatically obtained by a microcomputer when the control device is assembled, and the reference value is determined for at least one sensor and a new state of the sensor. And / or characterizing a new state of a component whose measured quantity is detected by the sensor, wherein the microcomputer detects a signal of at least one sensor applied during assembly of the control device, and The computer is solved by being configured to write the signal detected during assembly into the nonvolatile memory as the determined reference value.
[0005]
The advantage obtained by the control device according to the invention as defined in the characterizing part of claim 1 is that, when the control device is assembled, the reference value characterizing the initial state of the system to be controlled is automatically learned. is there. Thereby, the control device and the connected components are adapted. This has an advantageous effect on the accuracy of the sensor signal to be detected during the execution of the control device. The initial storage operation of the reference value for the sensor makes it possible to easily identify the appearance of aging during the execution operation. On the other hand, all that is required is to compare the reference value stored during the assembly of the control device with the instantaneous reference value under the same initial state. Furthermore, it is advantageous to set a wide range of manufacturing deviations for the sensor within a predetermined frame. This is because the reference value for each sensor is detected separately.
[0006]
Further advantageous embodiments and improvements of the invention are described in the dependent claims.
[0007]
According to an advantageous embodiment of the invention, an identifier is stored in the control device indicating whether or not at least one reference value for at least one sensor is stored in a non-volatile memory, the microcomputer comprising: At least one reference value is automatically detected by the microcomputer only when an inquiry is made as to whether or not the identifier is set effectively and it is determined that the identifier is not set effectively in the inquiry result. Written in non-volatile memory. As a result, the reference value is stored only in the operation state for executing the storage operation of the control device.
[0008]
Further advantageously, the control device comprises means for effectively setting the identifier after storage of the reference value. Thereby, for example, when the control device is assembled to the automobile, the detection and storage of the reference value by the control device can be achieved at one time.
[0009]
Further advantageously, after the microcomputer reads out the reference value and writes it in the nonvolatile memory, the identifier is written in the nonvolatile memory by the microcomputer. No additional circuit cost is required for this. The microcomputer can very easily query whether an identifier is set.
[0010]
More advantageously, the identifier is set as follows: That is, the identifier is set by establishing or releasing an electrical connection in the process of inserting the control device into the module slot to which it belongs. In this case, the electrical connection is only activated or deactivated after a predetermined time delay. This allows the control device to read at least one reference value during the time delay. This guarantees the following: In other words, the reference value is stored in the process of inserting the control device, and it is guaranteed that whether or not the control device is inserted for the first time can be identified from the outside.
[0011]
Further advantageously, the formed or released electrical connection path is effectively retained both after withdrawal of the control device from the module slot and after subsequent reinsertion into the module slot. This avoids reading and storing a new reference value for each plug-in process by the control device.
[0012]
Further advantageously, the formed or released electrical connection path is restored by mechanical action. In this case, an initial state similar to that before the initial assembly of the control device can be restored. As a result, it can be achieved that the control device can learn a new reference value even when, for example, the reference value by this sensor is still unknown after the sensor has been replaced.
[0013]
【Example】
Next, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
In FIG. 1, a reference numeral 10 indicates an automotive airbag control device. The control device 10 includes a microcomputer 11, a RAM 12, a ROM 13, an EEPROM 14, and an input / output circuit 15. The microcomputer 11 includes one PROM 16 as a characteristic. An acceleration sensor 17 is connected to the control device 10. Further, the control device 10 is provided with a switching output stage 18 for igniting the charge unit of the driver side and passenger side airbag. As a further sensor, a sheet occupation state identification sensor 21 is connected to the microcomputer 11.
[0015]
The sheet occupation state identification sensor 21 includes RC elements 20 and 19. The assembly position of the seat occupation state identification sensor 21 is a passenger seat of an automobile. The capacitor 19 is configured as a flat plate capacitor. The capacitance of this capacitor changes depending on the occupied state of the passenger seat. The capacitance of the plate capacitor changes greatly as soon as a person sits in the passenger seat. The RC elements 20 and 19 are supplied with an AC voltage having a fixed frequency. This alternating voltage can be generated using the control device 10, for example. The control device 10 evaluates the signal of the sheet occupation state identification sensor 21 with respect to the frequency during the operation period. When the accident occurrence state is signaled by the acceleration sensor 17, the microcomputer 11 triggers the charge ignition output stage 18 for the passenger side and driver side airbags. In this case, the output stage 18 is only for the case where the passenger seat is identified as occupied in the evaluation of the seat occupation state identification sensor 21 with respect to ignition of the charge of the airbag for the passenger seat. Make a connection.
[0016]
FIG. 2 shows an assembling process of the air bag control device 10. In this case, the plug connector 32 of the control device 10 is inserted into the module slot 31 to which the automobile 30 belongs. This process takes place at the end of the final assembly phase of the car 30. As soon as the operating voltage is applied to the control device 10 by the insertion of the control device, the program shown in FIG.
[0017]
Following the program start step 40, the microcomputer reads the configuration word (configuration) from the PROM 16. In the inquiry step 42, the microcomputer 11 detects whether or not an identifier is included in the constituent word. This identifier indicates whether or not one reference value related to the frequency of the signal of the seat occupation state identification sensor 21 for the passenger seat in the unoccupied state is already stored. If the reference value is already stored, the program ends at program step 46.
[0018]
If the reference value has not been stored yet, the stored content of the EEPROM 14 is erased in the program step 43. The erase of the stored contents of the EEPROM 14 in which the reference value is entered is for the following purpose. That is, for example, when the sensor 21 is replaced, the reference value of the previous sensor 21 is not carried over to the new sensor 21. Thereafter, in the program step 44, the frequency of the AC voltage signal of the sheet occupation state identification sensor 21 is measured. The following must be ensured during the phase of the assembly process of the airbag control device 10. That is, it must be ensured that the passenger seat is unoccupied so that the read frequency value is valid as a reference value for the unoccupied state of the seat. The measured frequency is written into the EEPROM 14. Subsequently, in the program step 45, the identifier is written into the PROM 16 by setting one or more bits. This identifier represents that the control device 10 has read the reference value of the sheet occupation state identification sensor 21. Thereafter, the program ends in program step 46. Subsequently, the microcomputer 11 starts executing the control program. A detailed description of this control program is omitted here.
[0019]
4a and 4b show two embodiments of the attachment member of the control device 10. FIG. These are integrated in the plug connector 32 of the control device 10. This ensures the following for the microcomputer 11 (which does not have a PROM) in a mechanical-electrical manner. That is, it is ensured that the microcomputer 11 automatically reads the reference value of the sheet occupation state identification sensor 21 during the assembly process of the control device 10 and generates an identifier indicating that the reference value is stored.
[0020]
In FIG. 4 a, a part of the plug connector of the control device 10 is indicated by reference numeral 32. A contact block 51 is integrated in the plug connector 32 as an attachment member. A voltage is supplied to the contact block 51 from the control device 10 side. A slide bar 50 is engaged with the contact block 51. This engagement relationship is shown only schematically for clarity. The slide bar 50 is connected to the connector pin 54 of the plug connector 32 via a connection line 53. In the process of assembling the control device 10, the slide bar 50 is pushed against the wall of the module slot 31 on the automobile 30 side. That is, the slide bar 50 is slid in the direction of the arrow by the assembling process. This sliding is performed until the protrusion 58 of the slide bar 50 is engaged with the notch of the contact block 51. Further, the slide bar 50 is insulated from the contact block 51 by the insulating layer 52.
[0021]
The program of the microcomputer 11 for this embodiment is shown in FIG. After the program start step 40, the microcomputer 11 measures the voltage at the contact pin 54. In a subsequent inquiry step 61, the microcomputer 11 checks whether the voltage at the contact pin 54 corresponds to the voltage at the contact block 51. If not, the microcomputer 11 evaluates this as the following identification state. That is, it is evaluated that the control device 10 has already been assembled once. Further, the microcomputer 11 ends the program at program step 46. If the voltage at contact pin 54 corresponds to the voltage at contact block 51, EEPROM 14 is erased at program step 43 and program step 44 is performed as described in FIG. Thereafter, similarly, the program ends at program step 46. By slowly pushing the control device 10 into the module slot 31, it is guaranteed that the program of FIG. 5 will be terminated anyway until the protrusion 58 is locked to the notch of the contact block 51.
[0022]
When the control device 10 is pulled out from the module slot 31 for maintenance, the program shown in FIG. 5 follows the inquiry step 61 when the control device 10 is newly assembled while the slide bar 50 remains in the locked state. finish.
[0023]
By using a mechanical tool, it is possible to return the slide bar 50 to its initial position. This is advantageous, for example, when a new passenger seat has to be assembled in the vehicle or when the reference value of the seat occupation state identification sensor has to be newly stored.
[0024]
FIG. 4 b shows a second embodiment for the attachment member of the control device 10. In this case, the contact rod 57 subjected to mechanical prestress is engaged with the conductive surface of the module slot 51. The contact rod 57 is provided on the bimetal 57. The bimetal 56 is connected to the plug connector 32 of the control device 10 via the contact bar 55. As soon as a current flows through the bimetal 56 during the assembly of the control device 10, the bimetal 56 is immediately warmed, whereby the bimetal 56 is deformed as follows. That is, the contact rod 57 is deformed so as to gradually lift. Finally, the contact rod 57 is slid into the groove portion of the insulating layer 52 of the contact block 51. As a result, energization through the bimetal 56 is interrupted. The contact rod 57 is fixed to the groove of the contact block 51 even after the bimetal 56 is cooled. This is because the contact rod 57 is prestressed accordingly. The same program as shown in FIG. 5 can be used for storing the reference value. The following is simply captured for this embodiment. That is, in this embodiment, the contact bar 55 cooperates with the bimetal 56 and the contact rod 57 to replace the connecting line 53 and the protrusion 58 of the first embodiment.
[0025]
The above-described present invention is not limited to the embodiments described so far. The present invention can be used whenever a sensor that requires a separate alignment adjustment is connected to the controller. Another example is a potentiometer that requires zero point adjustment or maximum value adjustment. This type of potentiometer is, for example, a load-potentiometer used to detect the engine load in an internal combustion engine or a throttle valve-potentiometer used to detect the position of the throttle valve in an output control device for the internal combustion engine.
[0026]
A further example is wheel inspection by measuring the peripheral speed. In this case, the initial value corresponding to the new tire characteristic value is given by the thread pattern and the tire pressure at a predetermined speed.
[0027]
【The invention's effect】
According to the present invention, learning of the reference value characterizing the initial state of the system to be controlled is automatically performed. Thereby, the connected components and the control device are adapted. This has an advantageous effect on the accuracy of the sensor signal to be detected during the continuous operation of the control device. The initial storage operation of the reference value for the sensor makes it possible to easily identify the appearance of aging during operation. This only requires comparing the reference value stored during assembly of the control device with the instantaneous reference value under the same initial conditions. Further advantageously, the manufacturing deviation for the sensor can be detected continuously within a predetermined frame.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of a control device according to the present invention.
FIG. 2 is a view schematically showing an assembling process of a control device according to the present invention.
FIG. 3 is a flowchart for a program executed in the microcomputer of the control device according to the present invention;
FIG. 4A is a first embodiment of a means for forming an electrical contact connection in assembling a control device to an automobile, and FIG. 4B is a second embodiment thereof.
FIG. 5 is a second flowchart for a program executed in the microcomputer of the control device according to the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Airbag control apparatus 11 Microcomputer 15 Input / output switching circuit 17 Acceleration sensor 19, 20 RC element 21 Sheet occupation state identification sensor 31 Module slot 32 Plug connector 50 Slide bar 51 Contact block 52 Insulating layer 53 Connection line 55 Contact bar 56 Bimetal 57 Contact rod 58 Projection

Claims (8)

In an electronic control device comprising a microcomputer, at least one nonvolatile memory, and an input / output circuit, wherein at least one sensor can be connected to the input / output circuit.
At least one reference value is automatically determined by the microcomputer (11) when the control device is assembled , and the reference value is determined for at least one sensor (21) and the new state of the sensor (21). / Or characterizing the new state of the component whose measured quantity is detected by the sensor (21),
The microcomputer (11) detects a signal of at least one sensor (21) applied at the time of assembly of the control device, and the microcomputer (11) obtains a signal detected at the time of assembly. electronic control unit and writes the non-volatile memory (14) as obtained reference value.   An identifier indicating whether or not at least one reference value for at least one sensor (21) is stored in the nonvolatile memory (14) is stored in the control device (10), and the microcomputer (11) Performs an inquiry as to whether or not the identifier is set effectively, and at least one reference value is set by the microcomputer (11) only when it is determined in the inquiry result that the identifier is not set effectively. The electronic control unit according to claim 1, wherein is automatically determined and written into the non-volatile memory.   The electronic control device according to claim 2, wherein the control device (10) has means for effectively setting an identifier after a reference value is stored.   4. The electronic control unit according to claim 3, wherein the microcomputer (11) writes corresponding data words in at least one non-volatile memory (14, 16) as a means for a valid set of identifiers.   5. The electronic control device according to claim 4, wherein an electronic programming device is assigned to the electronic control device, and the data word for the effective set of identifiers can be erased by using the electronic programming device.   As a means for a valid set of identifiers, a predetermined time delay is provided by additional components in the control device (10) during the insertion process of the control device (10) into the module slot (31) to which it belongs. The electronic control device according to claim 3, wherein an electrical connection path is formed or released together.   The formed or released electrical connection path is effectively maintained even after the controller (10) is pulled out of the module slot (31) and after reinsertion into the module slot. The electronic control device according to claim 6.   A mechanical component is disposed on the electronic control unit, wherein the formed or released electrical connection can be interrupted without disruptive action by the mechanical component. 8. The electronic control device according to 6 or 7.

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