JP4019840B2 - Network communication system and control processing system using the network communication system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of synchronizing timers in each ECU when a plurality of ECUs (electronic control units) are operated in cooperation according to a communication protocol of a multiplex communication system that detects and communicates carrier waves between ECUs.
[0002]
[Prior art]
In recent years, a system for network communication between a plurality of ECUs has become indispensable when a plurality of controls such as a vehicle are combined or executed. However, each ECU (so-called electronic control unit) usually has an independent timer, and when a plurality of ECUs execute one or a plurality of controls in conjunction with each other, the time of the timer between the ECUs. , And the need for matching the operation timing, control processing timing, and the like has been improved. In particular, in control and the like where high responsiveness is required, the influence of deviations in calculation timing and the like in each ECU is large, and such a requirement is further increased.
[0003]
As a method for network communication between a plurality of ECUs, for example, as disclosed in Japanese Patent Application Laid-Open No. 11-261611, there is a multiple communication system (so-called CSMA system: hereinafter referred to as CSMA system) that detects and communicates with a carrier wave. Are known. In the network communication by this CSMA method, it is impossible to estimate the time required for communication, that is, the time required for the message frame to be transmitted / received due to the collision of the message frames transmitted from each of the plurality of ECUs. close.
[0004]
Therefore, conventionally, in order to perform time synchronization between ECUs in network communication using the CSMA method, a method of explicitly preparing a master ECU and transmitting information when performing time synchronization from the master ECU has been adopted. For example, in the absolute time synchronization method of the distributed processing system described in Japanese Patent Publication No. 1-60853, it is disclosed that the time information is transmitted from the center device to the local device separately for the center device and a plurality of local devices. .
[0005]
[Problems to be solved by the invention]
However, even if a master ECU is prepared as in the prior art, there is a problem that time synchronization in consideration of communication error time (time lag) due to collision of message frames on the network communication bus cannot be realized. In other words, this error in communication time means that when a message frame including a timer value is transmitted from a predetermined ECU to another ECU, there are various types of messages other than the message frame related to the local timer value on the communication bus connecting these ECUs. Various message frames (ex. Operation data, operation results, etc.) are flowing. Therefore, the error time (time lag) until the message frame including the timer value is received by another ECU varies depending on the communication density on the communication bus.
[0006]
Conventionally, the error time (time lag) due to the collision of the message frame on the communication bus has not been taken into consideration in time synchronization between ECUs.
[0007]
Accordingly, the present invention has an object to provide a network communication system that realizes time synchronization between ECUs in consideration of communication error time due to collision of message frames on a communication bus, and a control processing system using this network communication system. To do.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the invention according to claim 1, in a network communication system in which a plurality of ECUs each having three or more local timers are connected, a master ECU is included in one of the ECUs. A slave ECU that is a remaining ECU of the ECU and is adapted to a local timer value of the master ECU, and includes a storage means for storing the local timer value provided in all of the ECUs, and the slave One of the ECUs adjusts the local timer value to the local timer value transmitted from the master ECU at the beginning of the process of time synchronization of the local timer and sets the local timer to the master ECU and the remaining slave ECUs. A function of transmitting a value, and the remaining slave ECU The local timer value transmitted from the master ECU is matched with the local timer value transmitted from the master ECU at the beginning of the process of synchronizing the timer and the local timer value transmitted from one of the slave ECUs and the transmission is received. A function of calculating a difference time from its own local timer value stored before and transmitting the difference time information to the master ECU, wherein the master ECU And having the function of transmitting its own local timer value to all the slave ECUs that need to be synchronized at least in time, and adding the difference time to the local timer value transmitted from one of the slave ECUs. It is characterized by having a function to set its own local timer value.
[0009]
In the invention according to claim 2, in the control processing system using the network communication system in which the plurality of ECUs are connected by a network and the control processing is performed in cooperation between the plurality of ECUs, the plurality of ECUs includes: Each of the plurality of ECUs is provided with a master ECU and a plurality of slave ECUs, and the master ECU is connected to the plurality of slave ECUs with the local timer. A first step of transmitting a timer value; and the local timer value transmitted by all of the plurality of slaves in the first step is stored as a local timer value of each slave ECU, and at least one of the slave ECUs One sends the stored local timer value to all other ECUs At least one of the slave ECUs having received the transmission in step 2 and the second step calculates a difference time between the local timer value by the transmission and the stored local timer value, and the master ECU The master ECU includes a third step of adding the difference time to the local timer value transmitted in the second step and storing the difference time information.
[0010]
As described above, in the first and second aspects of the invention, the master ECU and the slave ECU are defined at least among the ECUs that are to be synchronized in time, and the master ECU transmits its own local timer value to the slave ECU. Then, the local timer value of the slave ECU is matched with the local timer value of the master ECU. Then, the local timer value is transmitted from one of the slave ECUs to the other ECU. In this case, the local timer value between the master ECU and the slave ECU is shifted by a time lag due to a collision of message frames on the communication bus when the local timer value is transmitted from one of the slave ECUs to another ECU. Will be. Therefore, in a slave ECU other than the slave ECU that performed the transmission, the time lag when the local timer value is transmitted from one of the slave ECUs to the other ECU is calculated as the difference time, and the difference time is transmitted to the master ECU. Send information. Then, by adding to the local timer value transmitted from the slave ECU by the difference time in the master ECU, the local timer values of all the ECUs, that is, the master ECU and the slave ECU can be synchronized.
[0014]
Claim 3 In the invention described in item 1, the master ECU is changed to another ECU among the plurality of ECUs at a predetermined timing.
[0015]
In this way, if the master ECU is changed, the reliability related to time synchronism increases as compared with the case where the master ECU is fixed. That is, even when the master ECU cannot function as the master ECU due to a failure or the like, it is possible to achieve time synchronization when the master ECU is changed.
[0016]
Claim 4 As described in the invention, the message frame includes information specifying which slave ECU the difference time is calculated in addition to the local timer value information, and the difference time information has passed a predetermined time. However, if it is not transmitted or / and at least not received by the master ECU, it may have a function of causing another slave ECU to calculate the difference time and transmitting it to at least the master ECU.
[0017]
In this case, even if the slave ECU that plays the role of transmitting the difference time information breaks down or an ECU that does not have the function of transmitting the difference time information is included in the slave ECU, A situation in which time synchronization cannot be achieved without information being transmitted to the master ECU can be avoided.
[0018]
Claim 5 When the local timer value cannot be transmitted within a predetermined time to the slave ECU that needs to be synchronized at least at the beginning of the process of synchronizing the time of the local timer as in the invention described in Or / and a means for detecting and determining when the difference time cannot be added to its own local timer value when the difference time information is received from one of the slave ECUs. When an affirmative determination is made by the detection means, the master ECU may be changed to one of the slave ECUs.
[0019]
In such a case, even when the ECU defined in the master ECU does not satisfy the predetermined failure or the function as the master ECU, the time synchronization is not achieved by changing the master ECU. You can avoid that.
[0020]
Claim 6 As described in the invention, the function of calculating the difference and transmitting it to at least the master ECU is a slave ECU that could not transmit the difference time, a slave ECU that was supposed to receive the information of the difference time, or a master Any one or a plurality of ECUs may be provided.
[0021]
Claims 7 Or claims 8 As described above, the timing for changing the master ECU may be the timing at which the vehicle is turned on or the timing at which the ECU is controlled, for example, the control execution start timing or the control end timing. In other words, it is desirable to set the timing so that the original control contents of the ECU are not interrupted or the local timer value is not changed during the control.
[0022]
Claim 9 In this invention, the local timer value is communicated on a message frame in the network communication system, and this message frame includes information defining which ECU is the current master ECU in addition to the local timer value information. It is characterized by being.
[0023]
In this way, even when the master ECU is changed as needed, time synchronization can be smoothly realized.
[0024]
Claim 1 0 In the invention described in the above, the message frame is an application message frame including control data and the like, and the application message frame includes the local timer value, master ECU information, and difference time information. Yes.
[0025]
Claim 1 0 , 1 1 If configured as described above, it is possible to suppress an increase in the total number of message frames by performing time synchronization as compared to the number of message frames used for control executed by the normal ECU. Efficiency is increased.
[0026]
Claim 1 2 As described in the invention described above, the local timer value is communicated on a message frame in the network communication system, and this message frame does not include other control data but only includes data for performing the time synchronization. It is also possible to do. For example, when there are many vehicle variations and product variations, the above-mentioned application message frame must be reconstructed when the control data differs for each variation. However, as in the present invention, a message frame dedicated to time synchronization can be provided. For example, regardless of variations, it is possible to realize time synchronization only by providing a message frame dedicated to time synchronization in an ECU group that requires time synchronization.
[0027]
Claim 1 3 As described in the invention described above, the system may include an ECU group that performs time synchronization and an ECU that does not perform time synchronization.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing a schematic configuration of a first embodiment of the present invention. The ECUs 1, 2, 3, and 4 are connected by a LAN (local area network) cable 5 indicated by a thick solid line. The LAN cable 5 transmits data to a transmission / reception task (not shown) of each ECU 1 to 4. At this time, a system indicated by a thin solid line indicates data transmission from the ECU 1 to the other ECUs 2 to 4, and a system indicated by a dotted line indicates data transmission from the ECU 2 to the other ECUs 1, 3 and 4. A system indicated by a one-dot broken line indicates data transmission from the ECU 3 to the other ECUs 1, 2, and 4, and a system indicated by a two-dot broken line indicates data transmission from the ECU 4 to the other ECUs 1 to 3. Such a network communication system between three or more ECUs employs the CSMA method.
[0029]
Each of the ECUs 1 to 4 includes a local timer (not shown). Then, processing such as control calculation in each of the ECUs 1 to 4 is executed according to each local timer value. The local timer values in the ECUs 1 to 4 are temporarily stored by the local timer itself or another storage part, and the timer count can be executed starting from the stored local timer value. The storage of the local timer value can be rewritten at any time.
[0030]
Next, an example of a so-called message frame format of data transmitted and received by the ECUs 1 to 4 using the LAN cable 5 will be described with reference to FIG.
[0031]
The message frame shown in FIG. 2 is an example in which one message frame is formed of 0 to 6 bytes, and each byte has a meaning as a set unit, and writing / updating is performed.
[0032]
In the 0th byte, the content indicating “mode number” is stored. For example, mode number = 0 is “identification means used when transmitting a local timer value from the master ECU to the slave ECU”, and mode number = 1 is “local from any one slave ECU to the master ECU and other slave ECUs. “Identification means used when transmitting the timer value” and mode number = 2 is “identification means used when transmitting the calculation result of the difference time of the local timer value to the master ECU”. Note that the mode number = 2 is “identification means used when transmitting the calculation result of the difference time of the local timer value from the slave ECU that performed this calculation to a slave ECU other than the slave ECU that performed this calculation and the master ECU. Even if it is positioned as “,” the same effect is exhibited. The difference time between local timer values will be described later.
[0033]
The first byte stores contents that mean “node number”. This node number is a management number that prescribes which ECU is the synchronization time information.
[0034]
The second byte stores the contents that mean “master node number”. The master node number is a management number that defines which ECU is the current master ECU. This master node number is unnecessary and can be omitted when the master ECU is fixed and determined. That is, this master node number is used to define which ECU is the current master when the master ECU and the slave ECU are switched at regular time intervals or at every control processing timing.
[0035]
In the 3rd to 4th bytes, the contents indicating “local timer value” are stored. The local timer value is a value of a local timer serving as a reference for processing timing such as a control calculation provided in each of the master ECU and each slave ECU. The local timers in the ECUs 1 to 4 write the local timer value at the third to fourth bytes, and change the local timer value by reading the local timer value. When the local timer value is transmitted in the 3rd to 4th bytes, the mode number is 0 or 1, and when the mode number is 0, the 3rd to 4th bytes are used. The local timer value of the master ECU is written. When the mode number is 1, the local timer value of the slave ECU is written. When the mode number is 2, nothing is written in the 3rd to 4th bytes, and the empty state is maintained.
[0036]
The contents of the fifth to sixth bytes mean “timer differential time”. This timer difference time is the difference time of the local timer value of the slave ECU calculated when the mode number is 2.
[0037]
Based on FIG. 3, a process of how the message frame described in FIG. 2 described above is transmitted and received between the ECUs 1 to 4 and how the local timer value of each ECU is updated and synchronized Will be explained.
[0038]
In FIG. 3, the ECU 1 is positioned as a master ECU. Then, the ECUs 2 to 4 are positioned as slave ECUs. That is, the master ECU 1 is positioned as an ECU having a local timer value as a first reference of a sequence for synchronizing the local timer values of the ECUs 1 to 4, and the slave ECUs 2 to 4 are ECUs that are time-synchronized depending on the master ECU 1. . FIG. 3 shows the passage of time t in the downward direction on the page. In addition, (1) to (2) describe timings or sequences between ECUs at each timing. FIG. 4 shows an example of how the local timer values in the ECUs 1 to 4 are specifically updated and the time is synchronized when the sequence shown in FIG. 3 is executed. In the column of the timing t1 in FIG. 4, an example of disjoint local timer values at a stage where time synchronization is not established between the ECUs 1 to 4 is described.
[0039]
At timing t1, the ECU 1 transmits a message frame A including an internal local timer value to each of the slave ECUs 2 to 4. (This corresponds to (1) in FIG. 3)
When the example shown in FIG. 2 is adopted for the message frame A at this time, mode number = 0, node number = 1 (“1” is the case where the message frame is transmitted by the ECU 1. , The node number is shifted to “2-4” as needed.), Master node number = 1 (for example, the master node number = 1 when the current master node is in ECU 1), local timer value = 12 Second 345 (corresponding to {circle over (1)} in FIG. 4), timer difference value = empty (current t1 is empty because it is not the timing for transmitting the differential time).
[0040]
After the master ECU 1 transmits the message frame A at the timing t1, until each of the slave ECUs 2 to 4 receives the message frame A, the message frame A collides with other message frames on the LAN cable 5 or the like. An error time, that is, a time lag Tsys1 (corresponding to (2) in FIG. 3) occurs. Therefore, the slave ECUs 2 to 4 receive the message frame A from the master ECU 1 at the timing t2 when the time lag Tsys1 has elapsed from the timing t1. (This corresponds to (3) in FIG. 3)
When the message frame A is received at the timing t2, the local timer values of the ECUs 1 to 4 have a time lag Tsys of 1 hour as compared with the local timer value at the timing t1, as shown in the upper column of the timing t2 in FIG. The local timer value is set. Here, the time lag Tsys1 is set to 5 milliseconds.
[0041]
Then, the slave ECUs 2 to 4 that have received the message frame A rewrite and store the local timer value (= 12 seconds 345) stored in the message frame A. (Corresponding to (4) in FIG. 3)
This processing is performed at the same time as the ECUs 2 to 4 receive the message frame at the timing t2.
[0042]
The predetermined elapsed time Tw1 is a predetermined time that defines the time until the next message frame is transmitted. For example, it is a timing at which a transmission task is transmitted. In this embodiment, the interval Tw1 is 100 milliseconds as an example. (Corresponding to (4) in FIG. 3)
Accordingly, when the ECUs 2 to 4 set the local timer values transmitted from the ECU 1, only the ECU 1 has the local timer value of 12 seconds 350, and the other ECUs 2 to 4 have the local timer values of 12 seconds 345.
[0043]
Next, at the timing t3 when the elapsed time Tw1 has elapsed from the timing t2, the slave ECU 2, which is one of the slave ECUs, sends a message frame B including the internal local timer value to the other ECUs, here the master ECU 1 and the slave ECUs 3, 4. Send. (Corresponding to (5) in FIG. 3)
The message frame B at this time is mode number = 1 when FIG. 2 is taken as an example. The other bytes are node number = 2, master node number = 1, and local timer value = 12S445.
[0044]
At this time, as shown in the column of the timing t3 in FIG. 4, the local timer value is a value obtained by elapse of Tw1 from the time t2. Also in this transmission, it has a predetermined time lag Tsys2 (here, 10 milliseconds is taken as an example). (Corresponding to (6) in FIG. 3)
Then, ECU 1, 3, 4 receives message frame B from ECU 2 at time t 4 when time lag Tsys 2 has elapsed from time t 3. (Corresponding to (7) in FIG. 3)
As shown in the column of timing t4 in FIG. 4, the local timer value of each ECU at the time of reception is a value at which the time lag Tsys2 has elapsed compared to the local timer value at the time t3.
[0045]
The ECU 1 sets the local timer value transmitted from the ECU 2 at the timing t4 when the message frame B is received. As shown in the lower column of t4 in FIG. 4, 12 seconds 445 that is the value of the local timer of the ECU 2 at the timing t3 is set in the ECU 1. Even at this time, only the ECU 1 that is the master ECU in the ECUs 1 to 4 still differs from the local timer values in the other ECUs by the time lag Tsys2.
[0046]
Further, in the other slave ECUs other than the slave ECU 2 which has become the reference for rewriting the local timer value in the master ECU 1 during the elapsed time Tw2, the internal local timer value and the reference for rewriting the local timer value in the master ECU The difference time from the local timer value in the slave ECU, that is, the received local timer value is calculated. Here, the difference time between the local timer value (12 seconds 455) in the ECU 3 and the local timer value (12 seconds 445) stored in the message frame B transmitted from the ECU 2 is calculated. (Corresponding to (8) in FIG. 3)
The elapsed time Tw2 is synonymous with Tw1, and is a predetermined time until the next message frame is transmitted, and is 100 milliseconds as an example here.
[0047]
Then, at the timing t5 when the elapsed time Tw2 has elapsed from the timing t4, the message frame C including the difference time is transmitted from the slave ECU 3 to the other ECUs 1, 2, and 4. The message frame C may be transmitted only from the ECU 3 to the master ECU 1. At time t5 (corresponding to (9) in FIG. 3), as shown in FIG. 4, the elapsed time is compared with the local timer value of each ECU when the ECU 1 sets the local timer value received from the ECU 2. Tw2 minutes have passed.
[0048]
In FIG. 2, the message frame C has mode number = 2, node number = 3, master node number = 1, local timer value = empty, and timer difference value = 10 milliseconds.
[0049]
At timing t6 when the time lag Tsys3 has elapsed from timing t5, at least the master ECU 1 receives the difference time information. (Equivalent to ■ in Figure 3)
As shown in the column of timing t6 in FIG. 4, the time lag Tsys3 has elapsed at the timing t6. The time lag Tsys3 is set to 10 milliseconds as an example.
[0050]
When the master ECU 1 receives the difference time information at time t6, the master ECU 1 immediately adds the difference time to its own local timer value. (Corresponding to ■ 'in Fig. 3)
By executing such a sequence of timings t1 to t6, high time synchronization accuracy between the ECUs can be realized. Further, in this embodiment, it is possible to realize time synchronization between ECUs in consideration of error time due to collision of message frames on the network, that is, time lags Tsys1 to Tsys3.
[0051]
Next, a second embodiment according to the present invention will be described with reference to FIG.
[0052]
In the embodiment shown in FIG. 5, it is assumed that the master ECU has a function capable of receiving a message frame transmitted by itself as a function of the master ECU. When there is a master ECU having such a function, time synchronization between the master ECU and one or more slave ECUs can be achieved if there are one or more slave ECUs. As an essential function of the slave ECU, the local timer value of the slave ECU can be rewritten and stored in the local timer value transmitted from the master ECU, and the difference transmitted from the master ECU with respect to the local timer value of the slave ECU itself It is necessary to be able to add time information.
[0053]
FIG. 5 shows the transition of the local timer values in the master ECU and the slave ECU at each time t, and the sequence at each timing T1 to T4.
[0054]
At timing T1, the master ECU transmits its current local timer value to the slave ECU and itself.
[0055]
At timing T2, which is after the time lag Tadv due to transmission, the master ECU and the slave ECU simultaneously receive the local timer value Tadj transmitted from the master ECU at timing T1. Then, at this timing T2, the slave ECU changes and stores its own local timer value to the received local timer value (Tadj).
[0056]
The period between T2 and T3, which is between T2 and T3, is a predetermined time that defines the time until the next message frame is transmitted, and is synonymous with Tw1 and Tw2 in the first embodiment.
[0057]
At timing T3, the master ECU calculates a difference time between its own local timer value (Tadj + Tadv) received at timing T2 and the local timer value Tadj transmitted at timing T1. Then, the difference time information is transmitted to the slave ECU.
[0058]
At a timing T4 after a time lag of Tadv2 between T3 and T4, the difference time transmitted from the master ECU at the timing T3 in the slave ECU is added to the local timer value in the slave ECU.
[0059]
By executing such a sequence, the local timer values in the master ECU and the slave ECU are time-synchronized.
[0060]
Also in this second embodiment, a plurality of slave ECUs may be provided. When there are a plurality of slave ECUs, information transmitted from the master ECU, that is, a local timer value at timing T1, and a differential time at timing T3. Each slave ECU receives the information, and the difference time information may be added to the local timer value of the slave ECU.
[0061]
Further, in the second embodiment described above, the difference time is calculated at timing 3, but may be calculated at timing T2 and transmitted to the slave ECU at timing T3.
[0062]
The present invention is not limited to the above embodiment, and various modifications can be made.
[0063]
For example, in the above embodiment, the master ECU may be fixed to the ECU 1 in advance, and the master ECU may be changed among the ECUs 1 to 4 at every control timing or / and every predetermined time or / and every sequence start timing. May be. That is, even if the master ECU = ECU1 and the slave ECU = ECU2 to 4 this time, the master ECU = ECU2 and the slave ECU = ECU1, 3, 4 may be used in the next time synchronization process. If the master ECU can be changed at any time in this way, even when a specific ECU, for example, a fixed master ECU fails, time synchronization between the ECUs can be achieved when another ECU becomes the master ECU. There is a merit.
[0064]
In addition, the sequence in the above embodiment may be periodically executed at predetermined time intervals, or may be executed at each ON operation timing of the ignition switch when used in a vehicle or the like. The time synchronization sequence may be executed in accordance with the control execution timing and control end timing of the ECU that performs time synchronization. The control execution timing may be immediately before the start of control. Further, which ECU's control execution / end timing is used as a reference may be, for example, the execution / end of control in a higher hierarchy in the ECU group for time synchronization.
[0065]
In the above-described embodiments, the node number in the message frame is used as an identification signal that defines the difference time of the local timer value in which ECU. However, not only this, but for example, which ECU is the master of the difference time result. You may make it use in order to identify whether it is difference time in the case of being ECU.
[0066]
In addition, the time interval at which the message frame is to be transmitted to another ECU is defined in advance, and if a message frame including information on the difference time is not transmitted even if the specified time interval is exceeded, another ECU The difference time information may be transmitted using a node number that defines the difference time. Specifically, in the above-described embodiment, the ECU 3 calculates the difference time. If the node number in this case is 1, a message frame including the node number = 1 is transmitted even if it exceeds the specified time. If not, the difference time may be calculated in the ECU 4 and the difference time information in the ECU 4 may be transmitted as a node number = 2 in a message frame. The slave ECU 3 has a function of causing the other ECU 4 to execute detection and / or calculation of the difference time when the message frame including the node number = 1 has not been transmitted even after the specified time has elapsed and to transmit at least the master ECU. Alternatively, the master ECU 1 may detect that this message frame has not been received. When the message frame including the difference time information is set to be transmitted from the ECU 3 to another slave ECU such as the ECU 4, the other slave ECU, for example, the ECU 4 is provided with such a function. Also good. Note that the reason why the transmission is not performed even if the difference time exceeds the specified time is that there is an ECU failure or / and an ECU 2 to 4 that is an off-the-shelf general-purpose product that does not have a function for calculating the difference time. If it corresponds to the ECU 3 of the above-described embodiment, it can be expected that the difference time information will not be transmitted from the ECU 3 no matter what time. However, if the node number has the above functions, the compensation for ECU failure is increased, and / or a commercially available general-purpose ECU can be mixed and used on the network.
[0067]
Thus, even in an off-the-shelf general-purpose ECU, the local timer itself exists without omission, so if it has a function of reading and rewriting the local timer value and a function of transmitting and receiving the local timer value on a message frame, etc. Time synchronization can be taken. In the case of an ECU that does not have a function for reading / rewriting the local timer value and a function for transmitting and receiving the local timer value on a message frame or the like, a pseudo timer is provided in the ECU. If the local timer value is changed, rewritten, or transmitted, time synchronization can be achieved for all ECUs.
[0068]
Thus, the time synchronization method according to the present invention can be applied to a system in which an ECU that requires time synchronization and an ECU that does not require time synchronization coexist, and the collective unit of ECUs that require time synchronization is a system. The present invention can be applied even when two or more of them exist. For example, when time synchronization is achieved by the ECUs 1, 2, 3, and 4 and time synchronization is achieved by the ECUs 5, 6, and 7 (not shown) independently of the ECUs 1 to 3, for example, in the message frame shown in FIG. The master ECU may be divided and managed by the master node number, and a set unit for time synchronization may be distinguished by providing another byte.
[0069]
Further, in order to achieve time synchronization, the message frames A to C may be provided independently of other control message frames, or necessary data may be included in an existing application message frame for control or data. May be mixed. In this case, it is not necessary to prepare a special message frame for time synchronization. For example, in terms of vehicle control, any or all of the vehicle body speed, wheel speed, engine speed, intake air amount, steering rotation angle, etc. are stored as a plurality of data in the message frame and communicated between the ECUs. A mode number, a local timer value, a timer difference value, and the like necessary for realizing time synchronization between ECUs in the present invention may be added to such a message frame and transmitted / received between ECUs as an application message frame. . In this case, the data transfer efficiency on the network can be improved, and it is possible to suppress the error time itself from becoming longer due to collision of message frames. Note that the above-described node number and master node number may be added to the application message frame as necessary.
[0070]
In the example of the message frame described in FIG. 2, the local timer value byte and the difference time byte are separated. However, when the local timer value is transmitted in one byte or a group of bytes, the local timer value is transmitted. When storing a value and transmitting difference time information, one byte or a group of bytes may be shared so that the difference time is stored. Such sharing can be similarly realized when an application message frame is adopted.
[0071]
In addition, when the above-described embodiments are applied to a real-time distributed system connected via a CSMA network, it is possible to improve control performance in systems such as vehicle behavior control and integrated control that have severe processing response time constraints. is there. In the network system based on the CSMA system, the time lags Tsys1, Tsys2, Tsys3, Tadv, and Tadv2 in the above-described embodiment are uniformly the same time between any ECUs. Therefore, the present invention can be applied to any communication system in which the time lags Tsys1, Tsys2, Tsys3, Tadv, and Tadv2 are the same between any ECUs other than the systems connected by the CSMA system network.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a communication system of the present invention.
FIG. 2 is a diagram illustrating an example of a configuration of a message frame.
FIG. 3 is a diagram showing a time synchronization sequence of local timers of ECUs 1 to 4 according to the first embodiment.
FIG. 4 is a diagram showing a specific example when local timer values of ECUs 1 to 4 according to the first embodiment are time-synchronized.
FIG. 5 is a diagram illustrating a sequence illustrating a second embodiment.
[Explanation of symbols]
1-4 ... ECU
5 ... LAN cable

Claims (14)

    In a network communication system in which a plurality of three or more ECUs each having a local timer are connected, one of the ECUs is a master ECU, and the remaining ECUs in the ECUs are local to the master ECU. A slave ECU to be adjusted to a timer value is provided, and all the ECUs are provided with storage means for storing the local timer value, and one of the slave ECUs is the first in the process of time synchronization of the local timer The local timer value transmitted from the master ECU is adjusted to the local timer value and the local timer value is transmitted to the master ECU and the remaining slave ECU. From the master ECU at the beginning of the synchronization process The local timer value is adjusted to the local timer value transmitted, and the local timer value transmitted from one of the slave ECUs and the local timer value stored before receiving this transmission A function of calculating a difference time and transmitting difference time information to the master ECU is provided, and the master ECU transmits its own local timer value to all the slave ECUs at the beginning of the process of time synchronization of the local timer. A network communication system having a function, and having a function of adding the difference time to a local timer value transmitted from one of the slave ECUs to obtain its own local timer value, and the network communication Control processing device using the system.   In a control processing system using a network communication system in which a plurality of ECUs are connected by a network and a control process is performed in cooperation with the plurality of ECUs, the plurality of ECUs each have a local timer and a value of the local timer. Storage means for storing, in the plurality of ECUs, a master ECU and a plurality of slave ECUs time-synchronized with a local timer value of the master ECU are positioned, and the master ECU is connected to the plurality of slave ECUs A first step of transmitting the local timer value; and the local timer value transmitted by all of the plurality of slaves in the first step is stored as a local timer value of each slave ECU itself; At least one of the A second step of transmitting a timer value, and at least one of the slave ECUs receiving the transmission of the second step calculates a difference time between the local timer value of the transmission and the stored local timer value. And a third step of transmitting the difference time information to the master ECU, and the master ECU adding and storing the difference time to the local timer value transmitted in the second step. A control processing system using a characteristic network communication system.   3. The network communication system according to claim 1 or 2, wherein the master ECU is changed to another ECU of the plurality of ECUs at a predetermined timing, and control using the network communication system. Processing equipment. The local timer value is communicated on a message frame in the network communication system, and this message frame includes information specifying which slave ECU the difference time is calculated in addition to the local timer value information. In addition, if the information on the difference time is not transmitted even after a predetermined time has passed, and / or at least the master ECU does not receive the information, the other slave ECU calculates the difference time and at least the master The network communication system according to claim 1, 2 or 3 , and a control processing apparatus using the network communication system, comprising a function of causing the ECU to transmit. When the local timer value cannot be transmitted to a slave ECU that needs to synchronize at least at the beginning of the process of synchronizing the time of the local timer within a predetermined time, or / and the slave A means for detecting and determining when the difference time cannot be added to its own local timer value when the difference time information is received from one of the ECUs is provided. the network communication system and the network communication system of claim 1 or claim 2 or claim 3 or claim 4, characterized in that to change the master ECU in one of the slave ECU when the Control processing device used. The function of causing the other slave ECUs to calculate the difference time and transmitting it to at least the master ECU is the slave ECU that could not transmit the difference time, the slave ECU that was to receive the information of the difference time, or the master ECU 5. The network communication system according to claim 4 , and a control processing apparatus using the network communication system according to claim 4 , wherein the network communication system is provided in any one or a plurality of itself.   6. The network communication system according to claim 5, and a control processing apparatus using the network communication system according to claim 5, wherein the predetermined timing is every time the ignition switch of the vehicle is turned on. The network communication system according to claim 3 or 7 , and the control process using the network communication system according to claim 3 , wherein the predetermined timing is a control timing in any one of the plurality of ECUs. apparatus. The local timer value is communicated on a message frame in the network communication system, and this message frame includes information specifying which ECU is the current master ECU in addition to the local timer value information. control processing apparatus using the network communication system and the network communication system according to any one of claims 1 to 8, characterized. The local timer value is communicated on a message frame in the network communication system, and the message frame is an application message frame including control data and the like. The network communication system according to any one of claims 1 to 9 and control using the network communication system, including information on which ECU the master ECU is and information on difference time Processing equipment. 11. The network communication system according to claim 10 and a control processing apparatus using the network communication system according to claim 10 , wherein all of the message frames do not only perform time synchronization of local timers of the plurality of ECUs. The local timer value is communicated on a message frame in the network communication system, and the message frame does not include other control data but only includes data for performing the time synchronization. A network communication system according to any one of claims 1 to 9 , and a control processing apparatus using the network communication system. In the system, the plurality of the ECU, to any one of claims 1 to 12, wherein the time synchronization and ECU group performed the time synchronization is included an ECU not performed The described network communication system and a control processing apparatus using the network communication system. The network communication system according to any one of claims 1 to 13 , and a control processing apparatus using the network communication system, wherein a CSMA multiple communication system is employed as the network communication system.

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