JP2004066974A - Vehicle control device and its communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle control device and its communication method capable of flexibly meeting a combination of a plurality of control units. <P>SOLUTION: A meter ECU 11, i.e., a main control unit exchanges an information required for a control of respective parts of an automobile 1 by periodically carrying out communication among respective sub control units, i.e., body unity ECU21, key free ECU 22 and stabilization control ECU 23 through a pass line 10. In the automobile in which any one of the sub control units, for example the key free ECU 22 is not installed, the meter ECU 11 determines that the ECU 22 is not connected when it detects that no response to the answer requirement to the ECU 22 exists. The meter ECU 11 informs other ECU 21, 23 of the matter. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle control device including a plurality of control units mounted on a vehicle and controlling respective parts of the vehicle, and a communication method between the control units.
[0002]
[Prior art]
2. Description of the Related Art In recent years, electronic control of vehicles such as automobiles has been advanced, and with this, many electronic devices have been mounted on vehicles. Such an electronic device is composed of a plurality of control units that individually control each part of the vehicle in order to ensure variety of vehicle types and convenience of assembly and maintenance work. These control units are connected by a communication line and communicate with each other to exchange information, so that the entire vehicle is integrally controlled.
[0003]
Some of the plurality of control units are indispensably provided for operating the vehicle. In addition, in order to add functions according to the specifications of the vehicle or according to the user's preference, Some are installed as optional equipment. As described above, in order to integrally control a vehicle configured by a combination of various control units, it may be necessary to make the control operation of each unit different depending on the combination.
[0004]
In order to cope with such a need, in the conventional vehicle control device, the contents of the equipment mounted on the vehicle are written in a memory of one of the control units at the factory shipment stage, and each control unit is stored in the memory. By switching the control operation mode according to the read data, vehicle control according to a combination of control units in the vehicle is enabled. For example, as described in JP-A-8-296492, specification information is stored in an engine control device in advance, and the transmission control device receives the specification information via a communication cable, and receives the specification information. There is a device configured to select the control content according to the control.
[0005]
In other conventional technologies, multiple types of products with different operation modes are prepared in advance for each control unit, and they are appropriately selected and combined according to the contents of the equipment to support various equipments. I can do it.
[0006]
[Problems to be solved by the invention]
However, the above-described related art has the following problems. That is, in the method of writing the contents of the equipment into the memory at the time of shipment from the factory, it is necessary to write data according to the equipment of the vehicle for each vehicle to be manufactured. Will be raised. Also, when replacing a control unit equipped with this memory, it is necessary to write the data in the memory of the new unit again, which makes the maintenance troublesome.
[0007]
In addition, preparing multiple types of products having different operation modes in advance requires manufacturing and management costs, which not only leads to an increase in vehicle cost, but also causes erroneous operations during maintenance and repair. The risk of attaching the unit increases.
[0008]
Further, in any of the above-described methods, it is difficult to flexibly cope with a change in specifications after shipment from a factory, that is, the addition of a new control unit or the abolition of an existing unit.
[0009]
Therefore, an object of the present invention is to provide a vehicle control device and a communication method thereof that can flexibly cope with a combination of a plurality of control units.
[0010]
[Means for Solving the Problems]
A vehicle control device according to the present invention includes a main control unit, and a communication line electrically connected to the main control unit, and a plurality of sub-control units that control each part of the vehicle can be connected to the communication line. In the vehicle control device, in order to achieve the above object, the main control unit determines a connection state of each sub-control unit to the communication line based on a communication result with the plurality of sub-control units, While notifying the connection state to the sub-control unit connected to the communication line via the communication line, at least one of the main control unit and the sub-control unit connected to the communication line has a plurality of An operation mode is configured to be executable, and one of the plurality of operation modes is selected and executed according to the connection state. (Claim 1).
[0011]
According to such a configuration, for each vehicle, the main control unit determines the connection state based on the communication result with each sub-control unit, and each control unit executes an operation according to the determination result. That is, each control unit executes a control operation according to the combination of the control units in the vehicle, and it is not necessary to write data indicating the combination in advance at the factory. Also, a plurality of operation modes corresponding to an assumed combination are prepared in advance for each control unit, and one of the operation modes is selected and executed according to the combination. A plurality of combinations can be supported by a product number, and there is no need to prepare products of a plurality of product numbers for each operation mode. Therefore, the cost required for manufacturing and management can be reduced, and the occurrence of mounting errors can be prevented.
[0012]
In addition, since the main control unit determines the combination of each control unit and notifies each sub-control unit, the sub-control unit does not need to make the determination, and the operation of the sub-control unit is simplified, further reducing the cost. be able to.
[0013]
Further, in the vehicle control device according to the present invention, the main control unit can output a response request signal to one of the sub-control units to the communication line, and the sub-control units A predetermined response signal is output to the communication line in response to the response request signal to the control unit (claim 2).
[0014]
According to such a configuration, since each sub-control unit outputs a predetermined response signal in response to a response request signal from the main control unit, communication between a plurality of control units is performed smoothly without confusion, Further, the main control unit can reliably determine the connection state based on the presence or absence of a response signal from each sub control unit.
[0015]
Further, in the vehicle control device according to the present invention, the main control unit periodically transmits the response request signal to one of the sub-control units via the communication line, and The presence or absence of the response signal from the sub-control unit may be detected, and the connection state of the sub-control unit to the communication line may be determined based on the result (claim 3).
[0016]
According to such a configuration, the main control unit determines the connection state of each sub-control unit at any time, so that the combination of the control units is changed after shipment, or an abnormality occurs in any of the units during operation. Even in such a case, the change can be detected, and the operation mode of each control unit can be changed accordingly to cope with these situations.
[0017]
When the response signal is at least once, it is determined that the sub-control unit is connected to the communication line. On the other hand, when the number of transmissions without response reaches a predetermined number, the sub-control unit is It may be determined that it is not connected to the communication line (claim 4).
[0018]
According to such a configuration, it is determined that the connection is not established for the first time when the communication failure between the control units is repeated a predetermined number of times. Therefore, even if the communication with the main control unit fails due to noise in the communication line or poor connection of the connection, even though the sub control unit is connected, the sub control unit is immediately Is not determined to be not connected. Therefore, even if the communication is somewhat unstable, the main control unit can reliably determine the presence or absence of each sub-control unit.
[0019]
On the other hand, if the sub-control unit is not connected, no response signal can be received, so if the response signal is received even once, it can be determined that this sub-control unit is connected to the communication line. .
[0020]
Further, in the vehicle control device according to the present invention, the main control unit does not receive a response from the sub control unit to the transmission of the response request signal to the sub control unit determined to be connected to the communication line. When the number of transmissions reaches a predetermined number, it may be determined that the sub-control unit has failed, and the failure of the sub-control unit may be notified to the other sub-control units (claim 5). .
[0021]
According to such a configuration, when the sub control unit once determined to be connected stops responding due to some abnormality later, the main control unit determines that the unit has failed. Then, if each control unit performs control according to the failure state, it is possible to appropriately cope with the occurrence of the failure.
[0022]
For example, when the main control unit determines that at least one of the sub-control units has failed, the main control unit may further include a notifying unit that notifies the operator of the failure (claim 6). By doing so, the driver as the operator can detect the occurrence of the failure at an early stage, so that the danger of continuing driving without knowing the occurrence of the failure can be avoided. In addition, the service person as the operator can easily know the status of occurrence of the failure, so that the maintainability of the vehicle can be improved.
[0023]
Further, a communication method according to the present invention is a communication method between a plurality of control units connected to each other by a communication line to control each part of the vehicle. One control unit, which is provided as standard, transmits a predetermined response request signal to one selected unit among other control units connectable to the communication line via the communication line, and The other connected control unit outputs a predetermined response signal to the communication line when the response request signal transmitted from the one control unit corresponds to the control unit, and outputs the one control signal. The unit determines the connection state of the selection unit according to the presence or absence of a response signal from the selection unit (claim 7).
[0024]
According to such a configuration, similarly to the above-described vehicle control device, it is possible to grasp, for each vehicle, a combination of control units mounted on the vehicle. Therefore, by adopting such a communication method, it is not necessary to previously store the combination in the memory or to prepare a product having a plurality of product numbers corresponding to the combination, thereby reducing the cost required for manufacturing and managing the apparatus. be able to.
[0025]
Further, in the communication method according to the present invention, the one control unit periodically transmits the response request signal to the selection unit, and when the response signal from the selection unit is at least once, While it is determined that the selected unit is connected to the communication line, when the number of transmissions without a response from the selected unit reaches a predetermined number, it is determined that the selected unit is not connected to the communication line. (Claim 8).
[0026]
According to such a configuration, similarly to the above-described vehicle control device, the combination of the control units in the vehicle is determined at any time, and a change in the combination after shipment or abnormal operation of any of the control units is detected at an early stage. It is possible to do.
[0027]
Further, in this communication method, the one control unit is configured to transmit the response request signal to the selected unit determined to be connected to the communication line by a predetermined number of times without transmitting a response from the selected unit. , It may be determined that the selected unit is out of order (claim 9).
[0028]
According to such a configuration, similarly to the above-described vehicle control device, if the sub-control unit once determined to be connected no longer responds due to some abnormality, the unit is determined to be faulty. In addition, each control unit can take appropriate measures for occurrence of a failure.
[0029]
Further, similarly to the above-described vehicle control device, when the one control unit determines that at least one of the other control units is faulty, a predetermined notifying unit notifies the operator of the occurrence of the fault. (Claim 10).
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
A configuration of an embodiment in which the present invention is applied to a control device of an automobile will be described with reference to FIG. However, FIG. 1 is a block diagram showing a control device of this embodiment.
[0031]
As shown in FIG. 1, in the control device of this embodiment, a plurality of electronic control units (hereinafter, referred to as “ECUs”): a meter ECU 11; a body integrated ECU 21; And the stabilization control ECU 23 can be electrically connected.
[0032]
Among these units, the meter ECU 11 communicates with other ECUs to be described later via the bus line 10 to transmit various information such as the running speed of the automobile 1, the engine speed, and the remaining fuel amount of the automobile 1. It has functions of collecting information from various parts, displaying the information on the display unit 12 provided in the driver's seat, and sounding a buzzer (not shown) to notify the driver when there is an operation abnormality.
[0033]
The body integrated ECU 21 has functions of controlling blinking of a direction indicator lamp, a room lamp, and the like (not shown), controlling a door lock mechanism to lock and unlock the door, and the like.
[0034]
The meter ECU 11 and the body integrated ECU 21 are indispensable for operating various parts of the automobile 1 to realize the minimum necessary functions, and are therefore mounted as standard equipment on the automobile 1.
[0035]
On the other hand, the key-free ECU 22 and the stabilization control ECU 23 are mounted on the automobile 1 as optional equipment as needed. That is, the key-free ECU 22 performs a function of unlocking the door only when the driver carrying the electronic card key approaches the driver's seat, and automatically locking the door when the driver leaves the vehicle 1. is there. Further, the stabilization control ECU 23 is provided for the purpose of integrally controlling the operation timing and output of the brake and the engine to secure the stability of the vehicle and to enhance the maneuverability for the driver. It integrates an anti-lock brake system (ABS), traction control (TCS), etc.
[0036]
These equipments are additionally mounted on the above-mentioned standard equipments according to the product grade and user's preference. Therefore, even if the automobile 1 is of the same model, these ECUs 22 and 23 are on the market. Those that are mounted and those that are not are mixed.
[0037]
The plurality of ECUs 11 and the like are connected to each other by a common bus line 10, and perform data communication with each other via the bus line 10, thereby exchanging necessary information in the respective ECUs. Each ECU controls each part of the automobile 1 based on output signals from various sensors such as a vehicle speed sensor, an acceleration sensor, and a steering angle sensor provided in each part. Data communication can be performed between such ECUs based on a communication protocol known as, for example, LIN (Local Interconnect Network). Hereinafter, the operation will be described in accordance with the LIN protocol, but based on other communication protocols. It may be something.
[0038]
In the control device configured as described above, one of the plurality of ECUs, for example, the meter ECU 11 determines the connection state of each ECU based on the result of communication performed with another ECU 21 or the like, and determines the connection state. The control operation according to the state is executed, and the determination result is output to the bus line 10. That is, in this embodiment, the meter ECU 11 functions as a "main control unit", while the other ECUs 21, 22, and 23 function as "sub-control units". When the ECUs 21, 22, and 23 as sub-control units receive the data on the connection state of the other ECUs, they select an operation mode according to the connection state from a plurality of operation modes programmed in advance. Execute.
[0039]
As described above, in this embodiment, the meter ECU 11 grasps the connection state from the result of communication with the other ECUs, and notifies the other ECUs of the connection state, so that each ECU can respond to the connection state. Control operation can be performed, so that optimal control can always be performed corresponding to various combinations of the ECUs. Therefore, unlike the related art, there is no need to write data designating the combination at the factory. In addition, there is no need to prepare a plurality of ECUs corresponding to each combination, and it is only necessary to prepare one part number that can be executed by switching a plurality of operation modes for each unit.
[0040]
Next, a method in which the meter ECU 11 determines the connection state by communication with each ECU will be described with reference to FIGS. However, FIG. 2 is a waveform diagram illustrating the LIN protocol, and FIG. 3 is a flowchart illustrating communication processing. FIG. 4 is a flowchart showing a sub process in the communication process.
[0041]
As shown in FIG. 2, in the LIN protocol, one message frame includes a header part and a response part. That is, when the meter ECU 11 as the main control unit outputs, as a header portion, data including an identification code assigned to the ECU requesting data output among identification codes for identifying each ECU, the ECU to which the identification code is assigned is output. Outputs predetermined data as a response unit.
[0042]
For example, when the meter ECU 11 outputs data including an identification code indicating the body integrated ECU 21 to the bus line 10, the body integrated ECU 21 outputs predetermined data to the bus line 10 in response to the data (FIG. 2 (a)). )), All ECUs connected to the bus line 10 can receive this data. On the other hand, there is a case where the meter ECU 11 outputs the identification code assigned to itself, and in this case, the meter ECU 11 itself outputs predetermined data to the bus line 10 as a response unit (FIG. 2B). As described above, in this embodiment, in one message frame, the header portion including the identification code of each ECU and output by the meter ECU 11 corresponds to the “response request signal” of the present invention. The response section output from the ECU corresponds to a “response signal”.
[0043]
As described above, in this embodiment, the meter ECU 11 controls the bus line 10 as a master node in the LIN protocol, and the ECUs 21 and the like function as slave nodes to mutually transmit and receive data between the ECUs. . Specifically, the meter ECU 11 controls the data communication via the bus line 10 by executing a pre-programmed communication process shown in FIG.
[0044]
In this communication processing, when an ignition switch (not shown) is turned on by the driver and the meter ECU 11 is started, as shown in FIG. 3, the meter ECU 11 controls the bus line 10 and transmits predetermined data to each ECU. Is transmitted (step S1). Then, each ECU is sequentially designated as a “selection unit” (steps S2, S4, S6), and the sub-process shown in FIG. 4 is executed (steps S3, S5, S7), and the data output from each ECU is While receiving, the connection state of each ECU to the bus line 10 is determined based on the communication result. This sub-process will be described later in detail.
[0045]
Then, the process returns to step S1, and the processes of steps S1 to S7 are repeated. In this way, data from each ECU is periodically output to the bus line 10, and when each ECU receives this data, information necessary for control is exchanged between the ECUs and the information is updated as needed. Go on.
[0046]
Next, the sub-process shown in FIG. 4 will be described. In this sub-process, meter ECU 11 outputs header section data including an identification code corresponding to the previously specified ECU to bus line 10 (step S101). Since predetermined data is output as a response unit from the ECU specified by the identification code among the ECUs that have received this data, the meter ECU 11 takes in this data (step S102).
[0047]
Here, as described above, some of the ECUs, that is, the key-free ECU 22 and the stabilization control ECU 23 are optional equipment, and these ECUs 22 and 23 are not necessarily connected to the bus line 10. In addition, there may be some ECUs that cannot communicate due to a failure even though they are connected to the bus line 10. As described above, when some of the ECUs are not connected or have failed, even if the identification code specifying the ECU is transmitted, there should be no response from the ECU.
[0048]
That is, whether or not the ECU is correctly connected to the bus line 10 can be determined based on whether or not there is a response from the designated ECU. However, data transmission / reception may have failed due to a communication failure such as noise mixing, and it is not preferable to immediately determine that the ECU is not connected just because there is no response from the ECU. Therefore, in this embodiment, each time the identification code is transmitted to the designated ECU, it is determined whether or not there is a response from the ECU (step S103). The provided error counter is incremented (step S104), and when the value of the error counter reaches a predetermined value (step S105), it is determined that the ECU is not connected (step S107).
[0049]
The presence or absence of a response from each ECU can be determined by the presence or absence of a change in the level of the bus line 10 in the response section. As the error counter, for example, a RAM provided in the meter ECU 11, a memory in a CPU, a register, or the like can be used. It is arbitrary how many times the value of the error counter is determined to be “None” for the ECU. For example, using an 8-bit counter, when the upper limit value, that is, 255 in decimal, is reached. "None" can be determined.
[0050]
On the other hand, if the value of the error counter has not reached the predetermined value (for example, 255), the process returns to step S101 without immediately determining “none” (step S106), and the above processing is performed at a predetermined number of repetitions. Re-execute and attempt communication. The number of repetitions is arbitrary, but here the initial value is set to 3 as an example. Then, if there is no response from the designated ECU after repeating the above process a predetermined number of times, the sub-process is ended once and the process returns to the process of FIG.
[0051]
When the error counter reaches the predetermined value in step S105 and it is determined that the designated ECU is “none” (step S108), the number of repetitions is changed to 1. In this embodiment, as shown in FIG. 3, all connectable ECUs, that is, the body integrated ECU 21, the key-free ECU 22, and the stabilization control ECU 23 are sequentially operated regardless of whether they are actually connected to the bus line 10. Communication is specified. This is because, by doing so, the ECU that has been once determined to be “absent” due to a failure or the like and unable to perform communication becomes able to recognize the subsequent communication. However, if the ECU is not connected, it is useless to repeatedly try the communication. In this case, the number of repetitions is changed to try the communication only once as described above.
[0052]
Then, in order to notify each ECU that the ECU is not connected, the determination result is output to the bus line 10 (step S109). Each ECU recognizes that this ECU is not connected by receiving this.
[0053]
On the other hand, if there is a response in step S103, that is, if a response signal from the designated ECU has been received, the value of the error counter is decremented (step S110). However, if the value of the error counter is zero, it is left as it is. Then, it is determined that the designated ECU is present (step S111), the number of repetitions is set to three (step S112), and the result of the determination is output to the bus line 10 (step S109).
[0054]
Here, the reason why the error counter is decremented when there is a response from the designated ECU is as follows. That is, as described above, in this embodiment, the ECU is determined to be “none” only when the error counter reaches a predetermined value in consideration of the fact that communication may be unstable. ing. In other words, it can be said that the ECU in which the value of the error counter is relatively high has a high possibility that the operation state is unstable even if it is not determined to be “none”. Therefore, even if the communication is successful once with such an ECU, there is a possibility that the communication may be disabled again immediately after that, and in such a case, the determination is made “none” in a shorter time. Should.
[0055]
Therefore, while accumulating and counting the number of communication failures, if the communication is successful, the value is decreased, so that ECUs with high frequency of communication failures and unstable are determined to be "none" relatively early. On the other hand, for a stable ECU with a large number of successes, the time required to determine “none” becomes longer, and the presence or absence of each ECU can be appropriately determined according to the communication stability.
[0056]
As described above, in the control device of this embodiment, the meter ECU 11 periodically communicates with each ECU, determines the presence or absence of each ECU based on the communication result, and transmits the determination result to each ECU. are doing. Therefore, each ECU can grasp the device configuration of this control device, that is, which of the connectable ECUs is connected and which is not. Each ECU can optimize the operation of the vehicle 1 as a whole by appropriately switching and executing the processing corresponding to the above-described device configuration as needed.
[0057]
The processing that requires such switching includes, for example, the following. That is, in the vehicle 1 equipped with the stabilization control ECU 23, the functions of the ECU 23 prevent the occurrence of phenomena such as wheel lock and slippage. However, in order to ensure safety, the driver should be informed that the vehicle is in an unstable state where such a phenomenon may occur. As such a notifying means, for example, a display unit 12 installed in a driver's seat and controlled by the meter ECU 11 can be used.
[0058]
Therefore, when the stabilization control ECU 23 is provided, the meter ECU 11 needs to receive the output data and cause the display unit 12 to perform a predetermined warning display as necessary. On the other hand, when the stabilization control ECU 23 is not provided, such processing is unnecessary.
[0059]
In addition, the body integrated ECU 21 needs to change the control operation of the door lock mechanism depending on, for example, whether the key free ECU 22 is connected, that is, whether or not the key free function is provided.
[0060]
For switching these processes, a program for executing a plurality of operation modes according to the device configuration is incorporated in each ECU in advance, and these operations are performed according to the connection state of each ECU determined as described above. This is achieved by switching modes.
[0061]
An example of data communication between the ECUs performed in this manner will be described with reference to FIG. However, FIG. 5 is a timing chart showing data communication between ECUs.
[0062]
Here, a meter ECU 11 and a body integrated ECU 21 as standard equipment and a stabilization control ECU 23 among optional equipment are connected to a bus line 10 provided in the automobile 1 in FIG. It is assumed that the key-free ECU 22 is not connected. Each waveform in FIG. 5 shows a signal output from each ECU to the bus line 10.
[0063]
When the ignition switch is turned on by the driver and the meter ECU 11 starts executing the communication processing of FIG. 3, in the first message frame, that is, frame 1, both the header portion and the response portion are output from the meter ECU 11 (see FIG. 3). Step S1). As a result, the transmission data from the meter ECU 11 is received by the other ECUs, that is, the body integrated ECU 21 and the stabilization control ECU 23.
[0064]
Next, in the frame 2, the meter ECU 1 outputs an identification code corresponding to the body integrated ECU 21 and requests a response (steps S2 and S3). In response, the body integrated ECU outputs predetermined data. By receiving this data, the meter ECU 11 determines that the designated ECU, that is, the body integrated ECU 21 is “present”.
[0065]
In response to this, in the frame 3, the meter ECU 11 transmits the result of the determination, that is, data including information indicating that the body integrated ECU 21 is connected. Each ECU that has received the information recognizes that the body integrated ECU 21 is connected to the bus line 10.
[0066]
Subsequent frames 4 to 6 are response requests made by the meter ECU 11 to the key-free ECU 22 (steps S4 and S5 in FIG. 3). In this example, since the key-free ECU 22 is not connected and there is no response, the meter ECU 11 repeatedly makes a response request three times, and the value of the error counter corresponding to the key-free ECU 22 increases each time.
[0067]
If there is no response even if the response is repeated three times, the meter ECU 11 then makes a response request to the stabilization control ECU 23 (steps S6 and S7). In response to this, the stabilization control ECU 23 outputs predetermined data (frame 7), and in the subsequent frame 8, the meter ECU 11 outputs data including information indicating that the stabilization control ECU 23 is connected to the bus line 10. I do.
[0068]
As described above, when the communication processing cycle of FIG. 3 is repeated, predetermined data exchange is continuously performed between the ECUs 21 and 23 connected to the bus line 10 and the meter ECU 11, while the unconnected key free The value of the error counter corresponding to the ECU 22 gradually increases, and when it reaches a predetermined value (for example, 255), the ECU 22 is determined to be “none”. Then, the fact is transmitted from the meter ECU 11 to each ECU, and thereafter, the response request from the meter ECU 11 to the key-free ECU 22 is made only once per cycle. The cycle of one communication cycle is arbitrary, but may be, for example, about 50 to 100 ms in consideration of the communication speed and the number of connectable units.
[0069]
Further, when the ECU initially determined to be “present” does not respond during operation and is determined to be “absent”, the ECU may be malfunctioning. Therefore, in such a case, it is desirable that the meter ECU 11 transmits the fact to other ECUs and notifies the driver by displaying a warning on the display unit 12 or sounding a buzzer.
[0070]
As described above, in the control device of this embodiment, the meter ECU 11 performs data communication with each ECU, and determines the connection state of each ECU from the communication result. Then, the determination result is transmitted to each ECU via the bus line 10, and each ECU switches and executes the operation mode as necessary based on the result.
[0071]
Therefore, optimal control can always be performed irrespective of the combination of ECUs, and there is no need to write data at the factory before shipment or to prepare a plurality of product numbers corresponding to the combination for each unit, etc. Manufacturing and management costs can be reduced. Further, since the connection state of each ECU is periodically determined, it is possible to flexibly cope with a specification change after shipment, a unit failure, and the like.
[0072]
Moreover, since the meter ECU 11 that controls the display unit 12 functions as the main control unit, when an abnormality such as a failure occurs, the fact is immediately displayed on the display unit 12 to alert the driver. Can be.
[0073]
In addition, when the value of the error counter that counts the number of times of communication failure reaches a predetermined value, it is determined that “none” for the first time, and when the communication is successful, the value of this error counter is reduced. In addition, the number of erroneous determinations due to noise and the like is small, and the presence / absence can be appropriately determined in accordance with the stability of communication with each ECU.
[0074]
Only the meter ECU 11, which is the main control unit, determines whether or not each ECU is present. Other ECUs only need to switch the operation mode according to the determination result. The degree is high, and the burden on the developer and the development cost are reduced.
[0075]
The meter ECU 11 does not perform special communication to determine the presence or absence of each ECU, but performs communication for performing normal data exchange, and determines the connection state of each ECU based on the communication result. Therefore, the communication efficiency does not decrease by executing the presence / absence determination of each ECU.
[0076]
The present invention is not limited to the above-described embodiment, and various changes other than those described above can be made without departing from the gist of the present invention. For example, the combination of the ECUs in the above-described embodiment is merely an example for explaining the present invention, and other units may be combined. For example, the stabilization control ECU 23 in the above embodiment integrally controls an antilock brake system (ABS), a traction control (TCS), and the like. However, these are vehicles that are controlled by individual ECUs. Is also good.
[0077]
Further, the upper limit value of the error counter and the number of repetitions of the response request in the above embodiment are not limited to the above values, and may be other values.
[0078]
In the above-described embodiment, the communication between the ECUs is performed based on the LIN protocol. However, other communication protocols may be used.
[0079]
Further, in the above-described embodiment, the meter ECU 11 outputs the determination result to the bus line 10 each time it determines the presence or absence of each ECU. You may make it output collectively in a frame.
[0080]
【The invention's effect】
As described above, according to the first and seventh aspects of the present invention, the connection state of each unit to the communication line is determined based on the communication result between the control units. The operation of storing the combination is unnecessary, and there is no need to prepare a plurality of types of products corresponding to the combination, so that the manufacturing and management costs can be reduced.
[0081]
According to the second aspect of the present invention, the communication between the plurality of control units is smoothly performed without confusion, and the main control unit determines the connection state based on the presence or absence of a response signal from each sub control unit. The determination can be made reliably.
[0082]
According to the third and eighth aspects of the present invention, since the connection state of each control unit is determined as needed, the combination of each control unit is changed after shipment, or an abnormality occurs in any of the units during operation. Even in the case of occurrence, the change can be detected, and by changing the operation mode of each control unit accordingly, it is possible to cope with these situations.
[0083]
According to the fourth aspect of the present invention, even if communication with the sub-control unit fails due to noise mixing into the communication line or poor connection of the connection, the sub-control unit is immediately connected. It is not determined that they have not. Therefore, even if the communication is somewhat unstable, the main control unit can reliably determine the presence or absence of each sub-control unit.
[0084]
According to the fifth and ninth aspects of the present invention, if a control unit once determined to be connected is no longer responding due to some abnormality, the unit is determined to be faulty and each control The unit can take an appropriate response to the occurrence of a failure.
[0085]
According to the inventions of claims 6 and 10, since the driver can detect the occurrence of the failure at an early stage, the danger caused by continuing to drive without knowing the occurrence of the failure is avoided beforehand. can do.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a control device of this embodiment.
FIG. 2 is a waveform diagram illustrating a LIN protocol.
FIG. 3 is a flowchart illustrating a communication process.
FIG. 4 is a flowchart showing a sub-process in the communication process.
FIG. 5 is a timing chart showing data communication between ECUs.
[Explanation of symbols]
1 car (vehicle)
10 Bus line (communication line)
11 Meter ECU (Main control unit)
12 Display part (notification means)
21 Body integrated ECU (sub control unit)
22 Key Free ECU (Sub Control Unit)
23 Stabilization control ECU (sub-control unit)

Claims (10)

A main control unit,
A vehicle control device comprising: a communication line electrically connected to the main control unit; and a plurality of sub-control units that control each part of the vehicle, the vehicle control device being configured to be connectable to the communication line.
The main control unit determines a connection state of each sub-control unit to the communication line based on a communication result with the plurality of sub-control units, and determines a connection state of the sub-control unit connected to the communication line. While notifying the connection status via a communication line,
At least one of the main control unit and the sub-control unit connected to the communication line is configured to execute a plurality of operation modes, and selects and executes one of the plurality of operation modes according to the connection state. A vehicle control device comprising: The main control unit is capable of outputting a response request signal to one of the sub control units to the communication line,
The vehicle control device according to claim 1, wherein each of the sub-control units is configured to output a predetermined response signal to the communication line in response to the response request signal to the sub-control unit. The main control unit periodically transmits the response request signal to one of the sub-control units via the communication line, and determines the presence or absence of the response signal from the sub-control unit for each transmission. The vehicle control device according to claim 2, wherein the detection is performed, and a connection state of the sub control unit to the communication line is determined based on a result of the detection. The main control unit determines that the sub control unit is connected to the communication line when the response signal is at least once,
4. The vehicle control device according to claim 3, wherein when the number of times of transmission without a response reaches a predetermined number, it is determined that the sub-control unit is not connected to the communication line. The main control unit, when the number of transmissions without a response from the sub-control unit to the transmission of the response request signal to the sub-control unit determined to be connected to the communication line has reached a predetermined number, The vehicle control device according to claim 4, wherein it is determined that the sub-control unit has failed, and the failure of the sub-control unit is notified to the other sub-control units. The vehicle control device according to claim 5, further comprising: a notifying unit that notifies an operator of a failure when the main control unit determines that at least one of the sub-control units has failed. In a communication method between a plurality of control units connected to each other by a communication line to control each part of the vehicle,
One of the plurality of control units, which is provided as standard equipment in the vehicle, transmits a predetermined response request signal to one of the other control units that can be connected to the communication line, through the communication line. Send through,
The other control unit connected to the communication line outputs a predetermined response signal to the communication line when the response request signal transmitted from the one control unit corresponds to the control unit,
The communication method according to claim 1, wherein the one control unit determines a connection state of the selection unit according to presence / absence of a response signal from the selection unit. The one control unit periodically transmits the response request signal to the selection unit,
When the response signal from the selection unit is at least once, it is determined that the selection unit is connected to the communication line,
The communication method according to claim 7, wherein when the number of transmissions without a response from the selection unit reaches a predetermined number, it is determined that the selection unit is not connected to the communication line. The one control unit, when the number of transmissions without a response from the selection unit to the transmission of the response request signal to the selection unit determined to be connected to the communication line has reached a predetermined number, the one selection unit 9. The communication method according to claim 8, wherein it is determined that the unit has failed. The communication method according to claim 9, wherein when the one control unit determines that at least one of the other control units is faulty, a predetermined notification unit notifies the operator of the occurrence of the fault.

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