Source: https://patents.google.com/patent/JP5111613B2/en
Timestamp: 2019-12-10 20:43:46
Document Index: 504868113

Matched Legal Cases: ['art 13', 'art 12', 'art 34', 'art 35', 'art 30', 'art 30', 'art 30', 'art 44', 'art 45', 'art 40', 'art 40', 'art 10', 'art 13']

JP5111613B2 - Communication device, communication system, and communication method - Google Patents
Communication device, communication system, and communication method Download PDF
JP5111613B2
JP5111613B2 JP2010536685A JP2010536685A JP5111613B2 JP 5111613 B2 JP5111613 B2 JP 5111613B2 JP 2010536685 A JP2010536685 A JP 2010536685A JP 2010536685 A JP2010536685 A JP 2010536685A JP 5111613 B2 JP5111613 B2 JP 5111613B2
JP2010536685A
JPWO2010052892A1 (en
啓史 堀端
2008-11-04 Priority to JP2008283539 priority Critical
2008-11-04 Priority to JP2008283538 priority
2008-11-04 Priority to JP2008283539 priority
2009-11-03 Application filed by 株式会社オートネットワーク技術研究所, 住友電装株式会社, 住友電気工業株式会社 filed Critical 株式会社オートネットワーク技術研究所
2009-11-03 Priority to PCT/JP2009/005835 priority patent/WO2010052892A1/en
2009-11-03 Priority to JP2010536685A priority patent/JP5111613B2/en
2012-04-05 Publication of JPWO2010052892A1 publication Critical patent/JPWO2010052892A1/en
2013-01-09 Publication of JP5111613B2 publication Critical patent/JP5111613B2/en
The present invention relates to a communication system that transmits and receives data between a plurality of devices. In particular, the device reduces the collision of the communication in the communication line connecting the communication apparatus which can improve communication efficiency, a communication system and a communication method including the pre-Symbol communication equipment as a relay device.
In recent years, systems in which a plurality of devices are connected, functions are assigned to the respective devices, data are mutually exchanged, and various processes are performed in cooperation have been used in various fields. For example, in the field of in-vehicle LAN (Local Area Network) distributed to vehicles, ECUs (Electronic Control Units) perform specialized processing, and are connected to each other by communication lines. Various functions are realized as a system by exchanging.
The number and types of ECUs connected to the communication line increase with the specialization of functions realized by the ECU and the increase and diversification of functions that can be realized. Furthermore, since various functions are expected as a system, it is necessary for each ECU to share data and cooperate, and the amount of data to be transmitted increases.
An increase in the amount of data transmitted and received on the communication line causes a data delay due to collision (collision). Significant data delays can be fatal to driving functions such as brake control by the ECU.
FIG. 23A and FIG. 23B are explanatory diagrams illustrating an example in which communication of data from the ECU collides with the communication line. FIG. 23A shows a connection configuration of ECU (A) to ECU (E). The ECU (A) to ECU (E) are connected to the communication line in a bus type, and can transmit data when the communication line is released. FIG. 23B shows the transmission timing from each ECU in time series. As shown in FIGS. 23A and 23B, the ECU transmits data at predetermined intervals. Although the predetermined interval fluctuates somewhat due to the operation of the ECU itself, it is usually a substantially constant interval. In order to avoid transmission collisions as much as possible, there are cases where each ECU is devised such as shifting the interval to 10 milliseconds, 12 milliseconds, 15 milliseconds, or the like. However, there is a timing at which a plurality of ECUs attempt to transmit data almost simultaneously, such as at time t in FIG. 23B, every period of the least common multiple of the transmission interval of each ECU. Occurs.
On the other hand, regulations such as FlexRay, in which transmission / reception is controlled by a time trigger protocol (TTP), time-divides a predetermined communication cycle between ECUs to communicate within an assigned period, thereby avoiding a collision. . However, it is desirable that the present invention can be applied to a CAN (Controller Area Network) that performs event trigger control that is normally used in a vehicle-mounted LAN without being restricted by the definition of the time trigger protocol.
Patent Document 1 proposes a technique for controlling so that communication between ECUs does not interfere and collide by a method applicable to CAN. In the technique disclosed in Patent Document 1, each ECU has a time measuring means to measure the transmission timing of data from other ECUs, and when the transmission from other ECUs is completed, the ECU itself starts transmission Thus, the collision of communication is avoided by determining the transmission timing of its own data.
Also, in order to avoid collisions due to an increase in the number of ECUs connected to the communication line, the communication line is divided into a plurality of parts, the ECUs are connected to different communication lines, and the different communication lines are connected by a relay device (gateway device). Thus, a configuration is also implemented in which data is relayed to a relay device (for example, Patent Document 2). As a result, the number of ECUs connected to the communication line is reduced, so the amount of communication can be reduced, and data collisions can be avoided. In this case, ECUs that commonly use data are grouped into groups, so that wasteful use of communication lines can be suppressed and collisions can be avoided.
In Patent Document 3, ECUs in the field of in-vehicle LANs are divided into a plurality of groups, each group is connected to a communication line, and the communication line is further connected by a relay device (gateway device). A technique is disclosed that preferentially relays high-priority data based on the degree, so that transmission of high-priority data is not greatly delayed even when the communication load of the communication line increases.
In a CAN that is used as a standard in an in-vehicle LAN, the message ID added to the message corresponds to the priority, and when the message ID is interpreted as a numerical value, a message having a smaller value is more preferentially transmitted. (Non-Patent Document 1).
When a relay device tries to relay a message received from an ECU connected to one communication line or a message created from the message to the other communication line, even if the message can be transmitted on one communication line, When a message having a higher priority is being transmitted on the other communication line, the relay device may not be able to transmit because the priority is low. At this time, other messages to be relayed from one communication line cannot be transmitted and stay.
In this case, even if the message is a message that should be received almost simultaneously by a device that requires the message, the message stays when the message passes through the relay device, so that the message reception is synchronized. It cannot be secured.
Therefore, a method of adjusting the transmission timing of each message so that the message does not stay in the relay apparatus can be considered. Applying the invention disclosed in Patent Document 1, each ECU has time measuring means to measure the transmission timing of data from other ECUs, and transmits itself when transmission from other ECUs is completed Communication collision is avoided by determining the transmission timing of its own data so as to start the communication.
JP 2007-60400 A JP 2002-16614 A JP 2005-159568 A Renesas Technology, "CAN Primer", published on January 31, 2006, [online], [searched on August 25, 2008], Internet <URL: http://documentation.renesas.com/jpn/products/ mpumcu / apn / rjj05b0937_canap.pdf>
By using the technique disclosed in Patent Document 1, it is possible to avoid a communication collision between devices connected in a bus type. However, in the configuration in which the transmission timing is determined based on the transmission of data from a specific device, when a failure occurs in the specific device and transmission cannot be performed, all other devices may determine the transmission timing. It may not be possible. Moreover, in the configuration based on the transmission of data from other devices to each other, there is a possibility that the transmission timing does not converge efficiently.
Furthermore, the processing load of each apparatus is heavy in the structure which always measures the transmission timing from another apparatus mutually and determines transmission timing. During the period when the communication line is free, processing for determining the transmission timing in each device is not necessary.
The present invention has been made in view of such circumstances, and is connected to the communication line when the transmission timing is adjusted among a plurality of devices connected in a bus shape to the communication line. The communication device effectively adjusts the transmission timing when there is a collision on the communication line, effectively reduces the communication load while reducing the processing load on each device, and is effective for each device. It is an object of the present invention to provide a communication device, a communication system, and a communication method that can improve communication efficiency by adjusting transmission timing.
A communication device according to the present invention is a communication device in which a plurality of devices for transmitting and receiving messages are connected to a communication line connected in a bus shape, and receives a part or all of a message transmitted to the communication line. A plurality of devices based on a comparison between a measuring means for measuring the number of messages transmitted during a predetermined monitoring time divided into a plurality of periods and the number of messages for each of the plurality of periods measured by the measuring means Determining means for determining whether or not there is a bias in the transmission timing of the message transmitted by the transmitter, and transmitting means for transmitting to the communication line an instruction message for instructing to advance or delay the transmission timing when it is determined that the determination means is present. It is characterized by providing.
In the communication apparatus according to the present invention, the determination unit includes a unit that determines whether or not a period during which a message is not transmitted among the plurality of periods is a predetermined number or more, and determines that the unit is a predetermined number or more. In this case, the transmission timing is judged to be biased .
Communication apparatus according to the present invention, the determining means, the maximum value of the number of messages in the plurality of periods, and means for determining whether a predetermined times the minimum value, said means at least a predetermined times When it is determined that there is a transmission timing, it is determined that there is a deviation in transmission timing.
In the communication apparatus according to the present invention, the measurement unit periodically measures the predetermined monitoring time as one cycle, and the determination unit determines that a predetermined number of cycles is determined to have no transmission timing bias. A means for determining whether or not to continue, and a means for transmitting to the communication line a message instructing to stop adjusting the transmission timing when it is determined that the means continues for a predetermined number or more. .
The communication apparatus according to the present invention includes means for determining a transmission time point of a message instructing adjustment to advance or delay transmission timing based on a distribution of the number of messages in each period measured by the measurement means in the monitoring time, If the determination means determines that there, characterized in that an indication message indicating the advancing or delaying adjustment of the transmission timing, are to be transmitted to the communication line in the transmission time.
Communication device according to the present invention, each message Yes so as to be transmitted periodically, if it is determined that there is the judgment means includes means for identifying a transmission period of the message each transmission timing is biased, The transmission means transmits the instruction message at a timing corresponding to the specified transmission cycle.
Communication device according to the present invention, the transmission unit, until it is determined that there is no by the determining means and that you have to transmit continuously the indication message.
The communication system according to the present invention is connected to a plurality of devices that transmit and receive messages and a plurality of communication lines to which the plurality of devices are connected in a bus type, and each of the devices connected to one communication line. In a communication system including a relay device that receives a part or all of a message from a device and relays it to a device connected to another communication line, the relay device is divided into a plurality of periods on one communication line The one communication based on a comparison between the measuring means for measuring the number of messages transmitted during the predetermined monitoring time and the number of messages for each of the plurality of periods measured by the measuring means in the plurality of periods. A determination means for determining whether or not there is a deviation in transmission timing of messages transmitted by a plurality of devices connected to the line, and when the determination means determines that there is a transmission timing, Means for transmitting an instruction message for instructing an adjustment to accelerate or delay the operation, and when each of the plurality of devices receives the instruction message, the means for detecting when a specific message is transmitted; And adjusting means for adjusting the transmission timing of the next own message by advancing or delaying so as to reduce the time difference based on the time difference between the time when the message is detected and the time when the message is transmitted by itself. To do.
In the communication system according to the present invention, the relay device includes means for specifying a message whose transmission timing is biased, and means for specifying a transmission cycle of each of the specified messages , wherein the transmission means is further specified. The instruction message is transmitted together with message identification information of a message whose transmission timing is biased at a timing according to the transmission cycle, and the adjusting means of the plurality of devices is configured to transmit the instruction message at a timing Specific means for specifying the message, determination means for determining whether the message identified by the message identification information transmitted together with the instruction message is a message transmitted by itself, and a message transmitted by the determination means by itself Is determined at the timing specified by the specifying means, Characterized in that it comprises a means to bring the transmission timing of the message.
The communication system according to the present invention comprises means for keeping the message transmission timing away from the timing specified by the specifying means when each of the plurality of devices is determined not to be a message transmitted by the determining means. It is characterized by.
The communication method according to the present invention includes a plurality of devices that transmit and receive messages and a communication line that is connected to each of the plurality of devices in a bus type, and a part of the message transmitted to the communication line or In a communication method with a communication apparatus that receives all, the communication apparatus measures the number of messages transmitted during a predetermined monitoring period divided into a plurality of periods, and measures each of the measured periods. Based on the comparison between the number of messages, it is determined whether or not there is a bias in the transmission timing of the messages transmitted by the plurality of devices, and if it is determined that there is a bias, an instruction message for instructing an adjustment to advance or delay the transmission timing It transmits to said several apparatus via a line, It is characterized by the above-mentioned.
In the present invention, whether or not there is a deviation in timing of messages transmitted to a communication line by a communication apparatus (relay apparatus) that receives messages transmitted to the communication line from a plurality of apparatuses connected in a bus shape to the communication line. To be judged. Note that the presence or absence of bias is determined based on a comparison of the number of messages for each of a plurality of periods. When it is determined that there is a bias, a message instructing adjustment to advance or delay the transmission timing from the communication device (or relay device) to each communication device is transmitted to the communication line. Thus, only when it is determined that there is a bias, the transmission timing is adjusted by each device. A plurality of devices connected to the communication line may try to adjust the transmission timing earlier or later, triggered by the fact that a message instructing transmission timing adjustment is transmitted from the communication device to the communication line. Therefore, it is not necessary to perform the process of adjusting the transmission timing at all times, and the load on each device is reduced.
In the present invention, among the plurality of periods included in the monitoring time, if the number of periods message is zero is equal to or larger than a predetermined number, it is determined that there is a deviation of transmission timing. Because there is a period in which the number of messages to be transmitted is zero, a bias is estimated in the transmission timing of the message, and it is necessary to constantly adjust by adjusting the transmission timing only when such a bias is estimated. Absent.
In the present invention, among a plurality of periods included in the monitoring period, the number of messages (maximum value) in the period in which the number of transmitted messages is maximum is the number of messages (minimum value) in the period in which the number of messages is minimum. when the predetermined times or more, it is determined that there is a deviation of transmission timing. If the number of messages in a certain period is more than a predetermined number of times in other periods, it is estimated that there is a bias in the transmission timing of the message, and it is necessary to constantly adjust by adjusting the transmission timing only when there is such a bias There is no.
In the present invention, the number of messages is periodically measured with a monitoring time as one period, and a predetermined number of periods when it is determined that there is no bias in transmission timing based on the number of messages measured in a plurality of periods in each monitoring time. In the case where it continues, the stop of the adjustment of the transmission timing is instructed. Thus, when the stable becomes uniform number of messages sent during the monitoring period, it is not necessary to perform adjustment processing of the transmission timing each device to each other.
In the present invention, based on the distribution of the number of messages in each period during the monitoring time, it is determined at which timing a message instructing adjustment of transmission timing should be transmitted. For example, in each period during the monitoring time, a period in which the number of messages to be transmitted is less than the other , or a period in which the number of messages is more congested than the other is specified, and it is determined that there is a deviation in transmission timing In this case, a message instructing adjustment of transmission timing is transmitted in a corresponding period in the next monitoring time. Since the transmission timing adjustment is started when each device receives a message for instructing adjustment, the transmission timing can be adjusted efficiently by transmitting a message for instructing adjustment at an appropriate effective timing. Made.
In the present invention, each message is transmitted periodically. An instruction message is transmitted at a timing corresponding to the transmission cycle so that the transmission cycle of the message related to the bias is made known to other message transmission apparatuses. By receiving the instruction message, each device can recognize the reception cycle as a transmission cycle of a message that is difficult to be transmitted to other communication lines, and shift the transmission timing so that it does not coincide with the transmission cycle. Is possible.
In the present invention, during the period when it is determined that there is a bias , the instruction message is continuously transmitted, and the transmission timing of the message is adjusted by each device based on the instruction message. When it is determined that there is no bias , the transmission of the instruction message is stopped, and the adjustment of the message transmission timing is stopped. As a result, the transmission timing is adjusted only when necessary.
In the present invention, the instruction message is transmitted at a timing according to the transmission cycle so that the transmission cycle of the message related to the deviation of the transmission timing is made known to the device that transmits other messages. Then, the device that has transmitted the message related to the bias adjusts the transmission timing based on the transmission timing of the instruction message, and the message related to the bias is transmitted from the next time at the reference timing. This makes it possible for each device to recognize the transmission timing of a message related to a deviation in transmission timing, which is efficient.
In the present invention, a message other than the message according to the deviation of the transmission timing, wherein the message transmission timing according to the deviation are controlled so as to be transmitted away. Thereby, it is controlled so that a large number of messages do not arrive at the relay apparatus following the message related to the transmission timing deviation . Adjustment makes it possible to prevent the transmission timing bias from further increasing / deteriorating, and improve communication efficiency.
In the case of the present invention, it is determined that adjustment is necessary when the transmission timing is adjusted between a plurality of communication devices connected in a bus shape to the communication line, and adjustment is made only when necessary. Therefore, it is possible to efficiently reduce communication collisions while reducing the processing load on each communication device, and to effectively adjust transmission timing to improve communication efficiency.
Further, according to the present invention, since the transmission timing is adjusted when the message stays in the relay device, transmission and reception of messages between a plurality of devices connected in a bus form to the communication line are relayed thereafter. It is possible to prevent messages from staying unnecessarily in the relay device. In addition, when it is determined that a relay device that receives a message from each device is necessary, the transmission timing is adjusted by transmitting an instruction message, so that each device constantly adjusts the transmission timing. Thus, it is possible to efficiently reduce communication collisions while reducing the processing load on each device, and improve the communication efficiency of the entire communication system.
When communicating via a wired connection via a communication line, especially in an in-vehicle LAN, communication is possible without using a solution such as increasing the communication speed and without applying a heavy processing load to each device. It is desirable to reduce collisions and to communicate more efficiently and at high speed. Even in such a case, according to the present invention, it is possible to effectively reduce communication collisions on the communication line and improve communication efficiency.
1 is a configuration diagram showing a configuration of an in-vehicle communication system in a first embodiment. It is a block diagram which shows the internal structure of ECU and the relay apparatus which comprise the vehicle-mounted communication system in Embodiment 1. FIG. It is explanatory drawing which shows the example of the content of the message transmitted / received between ECU ... connected to the communication line in Embodiment 1. FIG. 6 is an explanatory diagram illustrating an example of contents of a relay table according to Embodiment 1. FIG. 6 is an explanatory diagram illustrating an example of group classification for transmission timing adjustment processing in Embodiment 1. FIG. 6 is an explanatory diagram showing an outline of transmission timing adjustment processing by an ECU according to Embodiment 1. FIG. The time distribution at the time of transmission of each message before the adjustment process of the transmission timing by ECU in Embodiment 1 is shown. The time distribution at the time of transmission of each message after the transmission timing adjustment processing by the ECU in the first embodiment is shown. 6 is a flowchart illustrating an example of a procedure of message observation processing and adjustment necessity determination processing executed by the control unit of the relay apparatus according to the first embodiment. 6 is a flowchart illustrating an example of a procedure of adjustment necessity determination processing executed by a determination unit of the relay device according to the first embodiment. 6 is an explanatory diagram for describing a specific example of determination processing by a determination unit according to Embodiment 1. FIG. 10 is a flowchart illustrating an example of a procedure of adjustment necessity determination processing executed by a determination unit of the relay device according to the second embodiment. 10 is an explanatory diagram for describing a specific example of determination processing by a determination unit according to Embodiment 2. FIG. 10 is a flowchart illustrating an example of a procedure for determining whether adjustment is necessary or not, which is executed by the determination unit of the relay device according to the third embodiment. 10 is an explanatory diagram for describing a specific example of determination processing by a determination unit according to Embodiment 3. FIG. FIG. 10 is a configuration diagram showing a configuration of an in-vehicle communication system in a fourth embodiment. FIG. 11 is a block diagram showing an internal configuration of an ECU and a relay device that constitute an in-vehicle communication system in a fourth embodiment. 15 is a flowchart illustrating an example of a processing procedure when the control unit of the relay device in Embodiment 4 instructs adjustment of transmission timing. 15 is a flowchart illustrating an example of a determination processing procedure for determining whether or not a stay is being performed, which is executed by the determination unit of the relay device according to the fourth embodiment. 15 is a flowchart illustrating another example of a determination processing procedure for determining whether or not the object is staying, which is executed by the determination unit of the relay device according to the fourth embodiment. 10 is a flowchart illustrating an example of a processing procedure when the control unit of the relay apparatus in Embodiment 5 instructs transmission timing adjustment. 16 is a flowchart illustrating an example of a transmission timing adjustment processing procedure based on an instruction message by an ECU according to the fifth embodiment. FIG. 16 is an explanatory diagram schematically showing a specific example of a result of transmission timing adjustment processing by an ECU in the fifth embodiment. It is explanatory drawing which shows the example in which communication of the data from ECU collides with a communication line. It is explanatory drawing which shows the example in which communication of the data from ECU collides with a communication line.
Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. In the embodiment described below, a communication device according to the present invention is applied to a relay device in an in-vehicle communication system in which a plurality of ECUs mounted on a vehicle are connected and data transmission / reception between ECUs is relayed by a relay device. A case will be described as an example.
FIG. 1 is a configuration diagram showing the configuration of the in-vehicle communication system in the first embodiment. In the in-vehicle communication system, ECUs 1, 1,..., Which are devices for transmitting and receiving messages, communication lines 2a, 2b connecting ECUs 1, 1,... For each group, and communication lines 2a, 2b are respectively connected. And a relay device 3 that relays data transmission / reception between the ECUs 1, 1,.
The ECUs 1, 1,... Are connected in a bus form to the communication lines 2a, 2b, respectively. The ECUs 1, 1,... Are devices that can transmit data including numerical information of various physical quantities such as measured values, calculated values, and control values, or can be controlled by a microcomputer such as an engine and a brake in order to realize the functions of the vehicle. . When sending data including numerical information, the ECUs 1, 1,..., Put a “message” in which a plurality of data is collected and a message ID is assigned according to the data into a CAN (Controller Area Network) protocol. Send and receive according to.
The relay device 3 is also connected to the communication lines 2a and 2b in a bus shape, and the relay device 3 can receive all the messages transmitted to the communication lines 2a and 2b.
In the in-vehicle communication system described below, the ECUs 1, 1,... Adjust the message transmission timing in accordance with the control of the relay device 3 to improve the communication efficiency of the communication lines 2a, 2b.
FIG. 2 is a block diagram showing an internal configuration of the ECU 1 and the relay device 3 constituting the in-vehicle communication system in the first embodiment. The ECU 1 includes a control unit 10 that controls the operation of each component using a CPU (Central Processing Unit), an MPU (Micro Processing Unit), and the like, and a storage unit 11 that uses a memory such as an EEPROM (Electrically EPROM) or a flash memory. And a timer 12 that implements a timer function and a communication unit 13 that implements communication via the communication line 2a (or communication line 2b).
The control unit 10 of the ECU 1 receives power supplied from a power supply device such as a vehicle battery and an alternator (not shown) to control the operation of each component. The storage unit 11 stores a computer program that realizes transmission timing adjustment processing, which will be described later, or various types of information that the control unit 10 refers to during processing.
The timer 12 measures the passage of time by counting at a predetermined frequency. The control unit 10 can acquire time information at an arbitrary timing from the time measuring unit 12.
The communication unit 13 has a network controller chip or a network controller function, and realizes communication via the communication line 2a (or communication line 2b). In communication between the ECUs 1, 1,... And the relay device 3 via the communication lines 2a, 2b, messages are transmitted and received in accordance with the CAN protocol. Therefore, the communication part 13 implement | achieves transmission / reception of the message via the communication line 2a (or communication line 2b) based on the CAN protocol. For example, when the control unit 10 of the ECU 1 connected to the communication line 2a monitors the communication status on the communication line 2a by the communication unit 13, determines whether or not it can transmit a message, and can transmit it. Send a message to Specifically, the ECU 1 can transmit the message by the communication unit 13 while the other ECUs 1, 1,... Connected to the communication line 2a or the relay device 3 is not transmitting the message. According to the rules of CAN, the message ID functions as an arbitration field. When the binary number of the message ID is used, the longer the zero bit is, that is, the lower the numerical value when the message ID is interpreted as a numerical value, the higher the priority. Is done. When transmission of a message is attempted simultaneously by any one of the ECUs 1, 1,... And the relay device 3 connected to the communication line 2a, a message with a small message ID is transmitted first. Further, when any one of the ECUs 1, 1,... Connected to the communication line 2a and the relay device 3 transmits a message via the communication line 2a, the other ECUs 1, 1 connected to the communication line 2a. ,... Can receive messages simultaneously.
ECU1,1, ... comprised in this way transmits a message periodically based on the timer function in the time measuring part 12. FIG. The period is set for each message. That is, even a message transmitted from the same ECU 1 may include a message transmitted every 10 milliseconds and a message transmitted every 25 milliseconds. Each of the ECUs 1, 1,... Performs a process of mutually adjusting the message transmission timing as will be described later.
The relay device 3 uses a control unit 30 that controls the operation of each component using a CPU, MPU, etc., a storage unit 31 that uses a memory such as an EEPROM or a flash memory, and a memory such as a DRAM or SRAM. Temporary storage unit 32, timer unit 33 that realizes a timer function, first communication unit 34 connected to communication line 2a, second communication unit 35 connected to communication line 2b, communication line 2a, A determination unit 36 that monitors communication in 2b and determines whether or not transmission timing adjustment is necessary.
The control unit 30 receives power supplied from a power supply device such as a vehicle battery and an alternator (not shown) and controls the operation of each component.
The storage unit 31 stores a relay table 37 including a message ID to be relayed so that the control unit 30 can refer to the relay process.
In the temporary storage unit 32, information generated by the processing of the control unit 30 is temporarily stored, and a part of the information is used as a buffer and a message received for relaying is stored.
The timer 33 measures the passage of time by counting at a predetermined frequency. The control unit 30 can acquire time information from the time measuring unit 33 at an arbitrary timing.
The 1st communication part 34 and the 2nd communication part 35 implement | achieve transmission / reception of the message with ECU1,1, ... connected via communication line 2a, 2b. That is, messages are transmitted and received according to the CAN protocol.
Based on the messages received by the first communication unit 34 and the second communication unit 35, the determination unit 36 performs a process for determining whether transmission timing adjustment is necessary, which will be described later. The determination unit 36 notifies the control unit 30 when it is determined that adjustment is necessary.
In the in-vehicle communication system configured as described above, the ECUs 1, 1,... Periodically transmit messages at a preset transmission cycle. If the starting points of the transmission cycles are deviated from each other, the possibility of overlapping transmission timings decreases. However, since the starting point may be shifted due to each operation, there is a possibility that the transmission cycle is synchronized and the transmission timing is always overlapped. When the ECUs 1, 1,... Connected to the same communication line 2a (or communication line 2b) try to transmit almost simultaneously, a collision occurs and communication efficiency is reduced. In the event of a collision, delays occur, such as a message that has been postponed because the priority is relatively low, and is further interrupted by other high-priority messages that are transmitted later, reducing communication efficiency. To do. If the transmission timing is controlled so as not to overlap, the transmission is smoothly performed regardless of the priority level, and the communication efficiency is improved.
Therefore, in the in-vehicle communication system according to the first embodiment, the transmission timings from the ECUs 1, 1,... Do not overlap each other, and processing for mutual adjustment is performed so that the transmissions are evenly distributed. Improve communication efficiency.
In the ECUs 1, 1,..., Which ECUs 1, 1,... Transmit which messages are received and received and used for control are statically set. Each of the storage units 11 of the ECUs 1, 1,... Stores a message ID of a message transmitted by itself, a message ID of a message to be received, a transmission cycle, and the like. Based on the timer function, a message is created and transmitted at the stored transmission cycle.
FIG. 3 is an explanatory diagram showing an example of the contents of messages transmitted and received between the ECUs 1, 1,... Connected to the communication line 2a in the first embodiment. A message ID is assigned to a message transmitted and received between the ECUs 1, 1,... According to the content of data included in the message. In the explanatory diagram of FIG. 3, message IDs such as “010” and “200” are assigned. In the explanatory diagram of FIG. 3, the message ID is represented by 11 bits. For example, “010” represents “(0) 000 0001 0000”, and “200” represents “(0) 010 0000 0000” in hexadecimal. . At this time, when the message ID is interpreted as a numerical value, the smaller the numerical value, the higher the priority. That is, in the explanatory diagram of FIG. 3, the message with the message ID “010” has the highest priority. In the explanatory diagram of FIG. 3, the level of priority is represented by a number indicating the priority order.
In addition, each message is determined as to whether or not the message is allowed to be delayed from being transmitted to being received according to the contents. In the content example shown in the explanatory diagram of FIG. 3, a message whose message ID is “050” (“(0) 000 0101 0000”) is allowed to be delayed, but a message whose message ID is “010” is delayed. Not allowed.
Further, each message is divided into systems A, B, and C according to the contents of data included in the message. For example, if the ECUs 1, 1,... Are devices that control the body system of the vehicle, the messages transmitted and received are systems such as whether they are body systems, light systems, door systems, or window systems. Divided. Since messages with the same system are highly likely to be used for processing at the same time, it is desirable that they are received by the ECUs 1, 1,.
FIG. 4 is an explanatory diagram showing an example of the contents of the relay table 37 in the first embodiment. As shown in FIG. 4, the relay table 37 includes a message ID of a message to be relayed and information indicating the relay source and the relay destination. The relay source means the communication line 2a or 2b to which the message transmission source ECU 1 is connected, and the relay destination means the communication line 2a or 2b to which the message transmission destination ECU 1 is connected. In the example illustrated in FIG. 4, the communication line 2 a is represented by “0 (zero)”, and the communication line 2 b is represented by “1”. When the first communication unit 34 receives a message with the message ID “010” transmitted to the communication line 2a, the control unit 30 of the relay device 3 temporarily stores the message in the buffer of the temporary storage unit 32 and relays it. With reference to the table 37, it is determined that the communication line 2 b should be relayed, and the second communication unit 35 transmits the result. Note that the control unit 30 of the relay device 3 determines that relaying is unnecessary for a message with a message ID that is not included in the relay table 37.
In the in-vehicle communication system according to the first embodiment, the messages shown in FIG. 3 are classified into groups according to the priority of the message, whether the delay is allowed, and the system, and the transmission timing is adjusted efficiently.
FIG. 5 is an explanatory diagram illustrating a group classification example for transmission timing adjustment processing in the first embodiment. The example shown in FIG. 5 is an example in which the messages shown in FIG. 3 are classified.
In the example shown in FIG. 5, messages are classified into groups (1) to (4), and message IDs “010”, “020” (“(0) 000 0010 0000”) and Messages that are “180” (“(0) 001 1000 0000”), group (2), messages that have message IDs “150” (“(0) 001 0101 0000”) and “200”, group (3 ) Belongs to the message with the message ID “050”, and the message with the message ID “100” (“(0) 001 0000 0000”) belongs to the group (4). The master shown in FIG. 5 is a specific message that is used as a reference in each group in a message transmission timing adjustment process to be described later, and the number indicates the priority as a master. When the message with the highest priority is not transmitted due to a failure of the ECU 1 or the like, each ECU recognizes the message with the next highest priority as the master message in the group to which the message transmitted by itself belongs. Process.
The messages shown in FIG. 5 are classified into groups (1) to (4) as follows. First, classification is based on whether delay is allowed or not. Referring to the content example of FIG. 3, messages with message IDs “010”, “020”, and “150” are classified as messages that do not allow delay, and message ID “050” as a message that allows delay. ”,“ 100 ”,“ 180 ”, and“ 200 ”.
Next, messages classified as not allowing delay are classified by lineage. As a result, messages whose delay is not allowed are classified into messages (system C) having message IDs “010” and “020” and messages (system A) having “150”, respectively.
On the other hand, among messages classified as allowing delay, messages having a large message ID value and low priority are classified into the same system of messages not allowing delay. Specifically, among messages classified as allowing delay, the message with the lowest priority message ID “200” has the message ID “150” because the system is “A”. The message having the same classification as the message and the message ID “180” having the next lowest priority is classified as the message having the message ID “010” and “020” because the system is “C”. .
Of the messages classified as being allowed delay, those other than those classified into messages not allowing delay based on low priority are grouped. That is, a message with a message ID “050” and a message with “100” are grouped with one message each.
Messages classified as unacceptable delays and classified according to the system select a master for each classification. At this time, it is desirable for the master to select a message having the shortest transmission cycle in the group, that is, a message with the highest priority (usually delay is not allowed) as the master. Thereby, the classification into groups as shown in FIG. 5 is realized.
Based on the messages grouped in this way, the ECUs 1, 1,... That transmit each message send the messages belonging to the same group close to the master message transmission timing, so that the master messages are mutually transmitted. The transmission timing is adjusted so as to be separated from each other.
FIG. 6 is an explanatory diagram showing an outline of transmission timing adjustment processing by the ECUs 1, 1,... In the first embodiment. The upper part of FIG. 6 shows a relationship between the master message and the transmission timing relationship between the message and other messages belonging to the same group. The lower part of FIG. 6 shows the force (F) of approaching the master transmission timing for each of the other messages belonging to the same group as the master message according to the time difference between the message transmission time and the master message transmission time. The graph which shows a magnitude | size is shown.
The transmission timing of each ECU 1, 1,... In the first embodiment is adjusted in relation to the master message transmission timing as shown in FIG. The ECUs 1, 1,... Are different from the transmission time of the message transmitted by the master with respect to the transmission time of the master message belonging to the same group as the message transmitted by the ECU (= master transmission time−the time of the message transmitted by itself). The force F determined by the following equation (1) according to the transmission time) is added to the next transmission timing and transmitted. In equation (1), r is a time difference, and G and g are predetermined constants.
As a result, the ECU 1, 1,... Has a positive value when the transmission time of the message transmitted by itself is before the transmission time of the master message (left arrow at the top of FIG. 6). At the next transmission timing, the force F is added and delayed. On the other hand, when the transmission time of the message transmitted by itself is later than the transmission time of the master message (the right arrow at the top of FIG. 6), the force F becomes a negative value. It is decremented by F, and it is advanced. In the first embodiment, when the time difference from the master message transmission time is extremely large, the force F does not work so strongly, but when the time difference is a predetermined time difference, the timing is most strongly approached.
As described above, the ECUs 1, 1,... That transmit other messages belonging to the same group as the master message are next only for the time corresponding to the magnitude of the force F obtained from the time difference from the transmission time of the master message. The transmission timing of the master message is approximated to the transmission timing of the master message by advancing or delaying the transmission timing.
7A and 7B are explanatory diagrams schematically showing a specific example of the result of the transmission timing adjustment processing by the ECUs 1, 1,... In the first embodiment. FIG. 7A shows a time distribution before the adjustment process, and FIG. 7B shows a time distribution at the time of transmission of each message after the adjustment process. In FIG. 7A and FIG. 7B, the horizontal axis represents the time axis, and the transmission time of each message is indicated by an arrow. It should be noted that the time at which the master message is transmitted is shown on the upper side of the time axis, and the time at which messages other than the master are sent is shown on the lower side.
In the example shown in FIG. 7A, a message (hatching arrow) having a message ID “010” is transmitted a plurality of times. On the left side in FIG. 7A, the message ID is “050” for the message “180”. , “020”, “200”, “180” and “150” are close to each other. In contrast, the time difference between the transmission time of the message with the message ID “150” and the second transmission time of the message “010”, the transmission time of the message with the message ID “100”, and “ The time difference from the third transmission time of the “010” message is relatively large, and it can be said that the transmission timing of the messages from the ECUs 1, 1,.
On the other hand, in FIG. 7B, the master messages “050”, “010”, “150”, and “100” are adjusted by adjusting the transmission timing so that the transmission timings are separated from each other. The time difference at the time of transmission is substantially uniform. In addition, the messages with message IDs “020” and “180” are close to the transmission timing of the message “010” that is the message of the master of the same group, and the messages of the same group are received in proximity. It has been adjusted to be possible. Further, the message with the message ID “200” is brought close to the transmission timing of the master message “150”.
In this way, the transmission timing is adjusted mutually by the processing of each ECU 1, 1,. Thereby, the collision of the communication in the communication line 2a is reduced, and communication efficiency improves.
However, if ECU1,1, ... performs the above-mentioned process constantly, the processing load of each ECU1,1, ... will become heavy. In this case, it goes against the problem of reducing the processing load of the ECUs 1, 1,. Since the ECUs 1, 1,... Are desired to be simplified in configuration, for example, by reducing the memory, especially in the case of in-vehicle use, the processing should be simplified and the processing load should be further reduced.
Therefore, in the in-vehicle communication system according to the first embodiment, when each ECU 1, 1,... Performs the adjustment process as described above, the relay device 3 determines whether transmission timing adjustment between the ECUs 1, 1,. The ECUs 1, 1,... Are instructed and adjustments are made when instructed. The necessity of the adjustment process is determined based on the time distribution of the number of messages transmitted through the communication lines 2a and 2b. The relay device 3 measures the number of messages transmitted during the monitoring time divided into a plurality of basic periods for each basic period, and if the transmission timing of each message is biased, the transmission timing is It is determined that the adjustment should be made, and the ECU 1, 1,. The relay device 3 monitors all messages transmitted from the ECUs 1, 1,... For relay and relays messages that need to be relayed. Therefore, even if the time distribution of the total number of messages is observed, the processing load is excessive. It is hard to become.
Hereinafter, message observation processing and determination processing for determining necessity of adjustment by the relay device 3 will be described with reference to flowcharts.
FIG. 8 is a flowchart illustrating an example of a procedure of message observation processing and adjustment necessity determination processing executed by the control unit 30 of the relay device 3 according to the first embodiment. The control unit 30 starts measuring the monitoring time by the timer function of the time measuring unit 33, performs the message number measurement process during the monitoring time, and causes the determination unit 36 to determine whether adjustment is necessary. .
The control unit 30 starts timing of one basic period by the timer function of the timing unit 33 (step S1), and whether or not a message is transmitted to the communication line 2a (or communication line 2b) during the one basic period. Is determined (step S2). At this time, the case of transmitting the message for relaying is also included in the transmission.
When it is determined that the message has been transmitted (S2: YES), the control unit 30 adds the number of messages in the one basic period (step S3), and determines whether one basic period has elapsed (step S3). S4). The control unit 30 stores the number of messages for each basic period added in step S3 in the storage unit 31. It may be stored in a memory built in the control unit 30.
If the control unit 30 determines in step S2 that the message has not been transmitted (S2: NO), the process proceeds to step S4 to determine whether or not the basic period has elapsed (S4).
When it is determined that one basic period has not elapsed (S4: NO), the control unit 30 returns the process to step S2 and determines whether another message has been transmitted (S2). When it is determined that the basic period has elapsed (S4: YES), the controller 30 determines whether or not the monitoring time has ended (step S5). If the control unit 30 determines that the monitoring time has not yet ended (S5: NO), the control unit 30 returns the process to step S1 and starts measuring the basic period to measure the number of messages in the next basic period. (S1).
When determining that the monitoring time has ended in step S5 (S5: YES), the control unit 30 adjusts the transmission timing between the ECUs 1, 1,... According to the number of messages in each basic period included in the monitoring time. The determination unit 36 is made to determine whether it is necessary (step S6).
The control unit 30 determines whether or not adjustment is necessary in step S6 (step S7). If it is determined that adjustment is necessary (S7: YES), the controller 30 instructs adjustment. An instruction message is created and transmitted to the communication line 2a or the communication line 2b by the first communication unit 34 or the second communication unit 35 (step S8), and the process ends.
When it is determined in step S6 that the adjustment is unnecessary (S7: NO), the control unit 30 determines whether the adjustment is determined to be unnecessary for a predetermined number of times (step S9). ). When it is determined that the number of times that the determination unit 36 determines that the adjustment is unnecessary is continuously less than the predetermined number (S9: NO), the control unit 30 ends the process as it is.
When the determination unit 36 determines that the adjustment is unnecessary for a predetermined number of times or more (S9: YES), the control unit 30 issues an adjustment stop message that instructs the ECU 1, 1,. The data is created and transmitted to the communication line 2a or the communication line 2b by the first communication unit 34 or the second communication unit 35 (step S10), and the process ends.
When the instruction message is transmitted to the communication line 2a (or the communication line 2b), the ECUs 1, 1,... Connected to the communication line 2a receive this by the communication unit 13 and adjust the transmission timing described above. The execution of the process starts and continues until an adjustment stop message is received (see FIG. 7).
FIG. 9 is a flowchart illustrating an example of a procedure of adjustment necessity determination processing executed by the determination unit 36 of the relay device 3 according to the first embodiment. The processing procedure shown below is details of the determination as to whether or not the transmission timing needs to be adjusted in step S6 in the flowchart of FIG.
The determination unit 36 specifies the number of messages measured in each basic period obtained by dividing the monitoring time (step S611). Since the number of messages for each basic period is stored in the memory in the storage unit 31 or the control unit 30, the determination unit 36 performs processing with reference to this.
The determination unit 36 determines whether or not there is a predetermined number or more of basic periods in which the number of messages is zero among the basic periods for which the number of messages has been specified in step S611 (step S612). If the determination unit 36 determines that there are a predetermined number of basic periods in which the number of messages is zero (S612: YES), the determination unit 36 determines that transmission timing adjustment processing between the ECUs 1, 1,. S613), the process returns to step S7 shown in the flowchart of FIG.
If the determination unit 36 determines that the basic period in which the number of messages is zero is less than the predetermined number in step S612 (S612: NO), the determination unit 36 determines that the transmission timing adjustment processing is unnecessary (step S614). The process returns to step S7 shown in the flowchart of FIG.
FIG. 10 is an explanatory diagram for describing a specific example of determination processing by the determination unit 36 according to the first embodiment. In FIG. 10, the horizontal axis represents the time axis, the time points when messages are transmitted in each basic period including the monitoring time are indicated by arrows, and the time distribution of the number of messages measured during the monitoring time is shown. .
The monitoring time is divided into M basic periods T1, T2,. The basic period is, for example, the greatest common divisor of each transmission period of a message to be transmitted, or the shortest period among the transmission periods of all messages. The monitoring time is, for example, the longest period in the transmission cycle of all messages.
In each basic period T1, T2,..., TM, the number of messages measured by the control unit 30 is N1, N2,. In the example shown in FIG. 10, N2 and N4 are zero. When the determination unit 36 determines whether or not the basic period in which the number of messages is zero is equal to or greater than the predetermined number, if the predetermined number is 2, it is determined that the transmission timing needs to be adjusted in the example illustrated in FIG. (FIG. 9, S612: YES, S613). And the instruction | indication message which instruct | indicates adjustment is transmitted by the control part 30 of the relay apparatus 3, and adjustment processing is performed between each ECU1,1, ... in order to improve the bias | inclination of transmission timing.
In this way, in the in-vehicle communication system according to the first embodiment, the ECUs 1, 1,... Connected to the communication lines 2a, 2b mutually perform transmission timing adjustment processing, so the communication lines 2a, 2b Communication collision is reduced and communication efficiency is improved. Further, the relay device 3 connected to the communication lines 2a, 2b and monitoring the messages transmitted from the ECUs 1, 1,... For relaying observes the communication statuses on the communication lines 2a, 2b. .., 1,... Transmits an instruction message to adjust the transmission timing only when the transmission timings from the ECUs 1, 1,. Thus, the ECUs 1, 1,... Only need to perform the adjustment process when receiving the instruction message, and since it is not necessary to perform the process constantly, the processing load can be reduced, which is efficient.
In the first embodiment, the necessity of adjusting the transmission timing between the ECUs 1, 1,... Is determined based on whether or not the basic period in which the number of messages is zero is equal to or greater than a predetermined number among the plurality of basic periods in the monitoring time. Judgment was made by evaluating the transmission timing bias. On the other hand, in the second embodiment, when transmission exceeding the upper limit is performed in a certain basic period, it is determined that adjustment is necessary because the transmission timing of messages from the ECUs 1, 1,.
Since the hardware configuration of the in-vehicle communication system according to the second embodiment is the same as that of the first embodiment, the same reference numerals are given and detailed description thereof is omitted. Further, since the outline of the transmission timing adjustment process by the ECUs 1, 1,. The details of the adjustment necessity determination process by the determination unit 36, which is the difference from the first embodiment, will be described below.
FIG. 11 is a flowchart illustrating an example of the procedure of the adjustment necessity determination process executed by the determination unit 36 of the relay device 3 according to the second embodiment. The processing procedure shown below corresponds to another example of the details of determining whether or not the transmission timing needs to be adjusted in step S6 in the flowchart of FIG.
The determination unit 36 specifies the number of messages measured in each basic period obtained by dividing the monitoring time (step S621). Since the number of messages for each basic period is stored in the memory in the storage unit 31 or the control unit 30, the determination unit 36 performs processing with reference to this.
The determination unit 36 determines whether there is a basic period in which the number of messages is equal to or greater than a predetermined number among the basic periods for which the number of messages has been specified in step S621 (step S622). If it is determined that there is a basic period in which the number of messages is equal to or greater than the predetermined number (S622: YES), the determination unit 36 determines that the transmission timing adjustment processing between the ECUs 1, 1,... Is necessary (step S623). ), The process returns to step S7 shown in the flowchart of FIG.
If the determination unit 36 determines in step S622 that there is no basic period in which the number of messages is equal to or greater than the predetermined number (S622: NO), it determines that the transmission timing adjustment processing is unnecessary (step S624), and FIG. The process returns to step S7 shown in the flowchart of FIG.
In the determination process in step S622, it is determined whether there is a basic period in which the number of messages is a predetermined number or more. Here, the predetermined number is a predetermined ratio (for example, 80%) to the theoretical value of the number of messages that can be transmitted during the basic period from the communication speed of the communication lines 2a and 2b and the message size (number of bytes, number of bits, etc.). %). As a result, when there is a basic period in which the number of messages that can be transmitted, that is, messages are transmitted at a frequency close to the limit, it is evaluated that there is a bias in the transmission timing, and it is determined that adjustment is necessary.
FIG. 12 is an explanatory diagram for describing a specific example of determination processing by the determination unit 36 according to the second embodiment. In FIG. 12, as in FIG. 10 in the first embodiment, the horizontal axis represents the time axis, the time points when the message was transmitted in each basic period including the monitoring time are indicated by arrows, and the measurement was performed during the monitoring time. The time distribution of the number of messages is shown.
In the example shown in FIG. 12, in each basic period T1, T2,..., TM, the number of messages N2 in the basic period T2 among the number of messages N1, N2,. Suppose that it exceeds. In this case, the determination unit 36 determines whether or not there is a basic period in which the number of messages is a predetermined number or more, and determines that the transmission timing needs to be adjusted (FIG. 11, S622: YES, S623). And the instruction | indication message which instruct | indicates adjustment is transmitted by the control part 30 of the relay apparatus 3, and adjustment processing is performed between each ECU1,1, ... in order to improve the bias | inclination of transmission timing.
As described above, also in the in-vehicle communication system according to the second embodiment, the relay device 3 accurately determines whether or not the transmission timing needs to be adjusted, thereby reducing the load caused by the transmission timing adjustment processing performed by each ECU 1, 1,. However, it is possible to reduce communication collisions in the communication lines 2a and 2b and improve communication efficiency.
In the first embodiment, the necessity of adjusting the transmission timing between the ECUs 1, 1,... Is determined based on whether or not the basic period in which the number of messages is zero is equal to or greater than a predetermined number among the plurality of basic periods in the monitoring time. Judgment was made by evaluating the transmission timing bias. On the other hand, in the third embodiment, when the maximum value is equal to or greater than a predetermined multiple of the minimum value among the number of messages in each of the plurality of basic periods, the transmission timing of the messages from the ECUs 1, 1,. It is determined that there is a need for adjustment.
Since the hardware configuration of the in-vehicle communication system in the third embodiment is the same as that in the first embodiment, the same reference numerals are given and detailed description thereof is omitted. Further, since the outline of the transmission timing adjustment process by the ECUs 1, 1,... And the message number observation process by the control unit 30 of the relay device 3 are the same, detailed description thereof will be omitted. The details of the adjustment necessity determination process by the determination unit 36, which is the difference from the first embodiment, will be described below.
FIG. 13 is a flowchart illustrating an example of a procedure of adjustment necessity determination processing executed by the determination unit 36 of the relay device 3 according to the third embodiment. The processing procedure shown below corresponds to another example of the details of determining whether or not the transmission timing needs to be adjusted in step S6 in the flowchart of FIG.
The determination unit 36 specifies the number of messages measured in each basic period obtained by dividing the monitoring time (step S631). Since the number of messages for each basic period is stored in the memory in the storage unit 31 or the control unit 30, the determination unit 36 performs processing with reference to this.
Then, the determination unit 36 specifies the maximum value and the minimum value among the number of messages in each basic period specified in step S631 (steps S632 and S633). Based on the maximum value and the minimum value specified in steps S632 and S633, the determination unit 36 determines whether or not the maximum value is equal to or greater than a predetermined multiple of the minimum value (step S634). If the determination unit 36 determines that the maximum value is greater than or equal to a predetermined multiple of the minimum value (S634: YES), the determination unit 36 determines that transmission timing adjustment processing between the ECUs 1, 1,... Is necessary (step S635). Then, the process returns to step S7 shown in the flowchart of FIG.
On the other hand, when determining that the maximum value of the number of messages is less than a predetermined multiple of the minimum value in step S634 (S634: NO), the determination unit 36 determines that the transmission timing adjustment process is unnecessary (step S636). Then, the process returns to step S7 shown in the flowchart of FIG.
FIG. 14 is an explanatory diagram for describing a specific example of determination processing by the determination unit 36 according to the third embodiment. In FIG. 14, as in FIG. 10 in the first embodiment, the horizontal axis represents the time axis, the time points when the message was transmitted in each basic period including the monitoring time are indicated by arrows, and the measurement was performed during the monitoring time. The time distribution of the number of messages is shown.
In the example shown in FIG. 14, the message number N2 in the basic period T2 is the maximum value among the message numbers N1, N2,... NM measured by the control unit 30 in each basic period T1, T2,. Assume that the number of messages N3 in the basic period T3 is specified as the minimum value. The determination unit 36 determines whether or not the maximum number of messages is equal to or greater than a predetermined multiple of the minimum value. Here, if the predetermined multiple is, for example, five, the determination unit 36 determines that the transmission timing needs to be adjusted (FIG. 13, S634: YES, S635). And the instruction | indication message which instruct | indicates adjustment is transmitted by the control part 30 of the relay apparatus 3, and adjustment processing is performed between each ECU1,1, ... in order to improve the bias | inclination of transmission timing.
As described above, even in the in-vehicle communication system according to the third embodiment, the relay apparatus 3 accurately determines whether or not the transmission timing needs to be adjusted based on the deviation of the transmission timing, thereby adjusting the transmission timing performed by each ECU 1, 1,. While reducing the load caused by processing, it is possible to reduce communication collisions in the communication lines 2a and 2b and improve communication efficiency.
In the first to third embodiments, the relay device 3 is configured to measure the transmission timing of messages from the ECUs 1, 1,. However, the device that measures the transmission timing and transmits the instruction message is not necessarily the relay device 3. In the first to third embodiments, the relay device 3 is configured to measure the transmission timing. The relay device 3 transmits messages from the ECUs 1, 1,... Connected to the communication line 2a to the other communication line 2b. This is because all the messages are originally received and the processing is performed according to the message ID for relaying. Even if functions such as the above-described adjustment processing for determining necessity and instruction message transmission processing are added to the relay device 3, it does not cause an excessive load, and can be implemented without increasing the capability of the device. Is preferable. In addition, since the relay device 3 is connected to the plurality of communication lines 2a and 2b for the purpose of relaying, the determination of necessity of adjustment and the transmission process of the instruction message in both the communication lines 2a and 2b are realized by one device. it can. However, the present invention is not limited to this, and a specific device that determines whether adjustment is necessary and transmits an instruction message may be connected to each of the communication lines 2a and 2b in a bus type. The device may be a device only for adjusting the transmission timing, or one of the ECUs 1, 1,... Connected to the respective communication lines 2a, 2b functions as a specific device, and adjustment is required. It may be configured to perform a determination of NO and an instruction message transmission process.
In the fourth embodiment, the transmission timing is adjusted by the relay device 3 that is connected to different communication lines 2a and 2b and relays messages between the communication lines 2a and 2b. In communication based on CAN, transmission / reception is realized by performing arbitration using the message ID. Since arbitration is separately performed on different communication lines 2a and 2b, a message relayed from one communication line 2a may be continuously lost on the other communication line 2b by another high-priority message. . In this case, when messages that need to be relayed are transmitted from one communication line 2a side in succession, messages that cannot be relayed to the communication line 2b side accumulate in the relay device 3. Therefore, in the following fourth embodiment, in order to prevent message retention in the relay device 3 from increasing or worsening, the relay device 4 determines whether or not the transmission timing needs to be adjusted, and if necessary, transmission is performed. Make timing adjustments.
The configuration of the in-vehicle communication system in the fourth embodiment is the same as the configuration in the first embodiment except for the detailed processing in the relay device 4. Therefore, hereinafter, the same reference numerals are assigned to configurations common to the first embodiment, detailed description thereof is omitted, and differences are mainly described.
FIG. 15 is a configuration diagram showing the configuration of the in-vehicle communication system in the fourth embodiment. In the in-vehicle communication system, ECUs 1, 1,..., Which are devices for transmitting and receiving messages, communication lines 2a, 2b connecting ECUs 1, 1,... For each group, and communication lines 2a, 2b are respectively connected. And a relay device 4 that relays data transmission / reception between the ECUs 1, 1,. The relay device 4 is also connected to the communication lines 2a and 2b in a bus shape, and the relay device 4 can receive all the messages transmitted to the communication lines 2a and 2b.
FIG. 16 is a block diagram showing an internal configuration of the ECU 1 and the relay device 4 constituting the in-vehicle communication system in the fourth embodiment. The relay device 4 according to the fourth embodiment includes a control unit 40 that controls the operation of each component using a CPU, MPU, etc., a storage unit 41 that uses a memory such as an EEPROM or a flash memory, a DRAM, an SRAM, or the like. A temporary storage unit 42 using the memory, a timer unit 43 that realizes a timer function, a first communication unit 44 connected to the communication line 2a, and a second communication unit 45 connected to the communication line 2b, And a determination unit 46 that monitors communication on the communication lines 2a and 2b and determines whether or not transmission timing adjustment is necessary.
The control unit 40 receives power from a power supply device such as a vehicle battery and an alternator (not shown) and controls the operation of each component.
The storage unit 41 stores a relay table 47 including a message ID to be relayed so that the control unit 40 can refer to the relay process.
In the temporary storage unit 42, information generated by the processing of the control unit 40 is temporarily stored. A part of the temporary storage unit 42 is used as a relay buffer, and a message received for relaying is temporarily stored. At this time, it is assumed that the relayed message is stored in the buffer by a FIFO (First In First Out) method, read, and transmitted.
The timer 43 measures the passage of time by counting at a predetermined frequency. The control unit 40 can acquire time information from the timing unit 43 at an arbitrary timing.
The 1st communication part 44 and the 2nd communication part 45 implement | achieve transmission / reception of the message with ECU1,1, ... connected via communication line 2a, 2b. That is, messages are transmitted and received according to the CAN protocol.
The determination unit 46 performs a process of determining whether or not messages received from the ECUs 1, 1,... Via the communication lines 2a, 2b are staying in the buffer of the temporary storage unit 32 without being relayed. The determination unit 46 notifies the control unit 40 when determining that it is staying.
In the in-vehicle communication system configured as described above, the ECUs 1, 1,... Periodically transmit messages at a preset transmission cycle. If the transmission cycle start points deviate from each other, the transmission timings do not overlap. However, since the starting point may be shifted due to each operation, there is a possibility that the transmission cycle is synchronized and the transmission timing is always overlapped. When the ECUs 1, 1,... Connected to the same communication line 2a (or communication line 2b) try to transmit almost simultaneously, a collision occurs and communication efficiency is reduced. In the event of a collision, delays occur, such as a message that has been postponed because the priority is relatively low, and is further interrupted by other high-priority messages that are transmitted later, reducing communication efficiency. To do.
Moreover, since the priority is high between the messages transmitted from the ECUs 1, 1,... Connected to the communication line 2a, the messages are transmitted to the communication line 2a, and the message is connected to the communication line 2b by the relay device 4. When relayed from the ECU 1, 1,... To the communication line 2b, the message is stored in the buffer of the temporary storage unit 42 without being transmitted to the communication line 2b because the priority is low in the communication line 2b. It may stay. Even if the messages are to be received almost simultaneously by a device that requires the message, it is possible to ensure the synchronization of message reception by staying in the relay device when the message passes through the relay device. Can not.
On the other hand, if it is controlled so that other messages are transmitted evenly and in a time-separated manner from the transmission time of the messages that are staying, transmission is made smoothly regardless of the priority level, Communication efficiency is improved. Even if a message stays in the relay device 4, if the message does not reach the relay device 4 and arrives at an interval, the message that has stayed until then is relayed by several attempts. This is because it can be expected that the completion and the retention will be prevented from increasing or deteriorating.
Therefore, in the in-vehicle communication system according to the fourth embodiment, the relay device 4 that relays transmission and reception of messages mutually adjusts so that transmission timings from the ECUs 1, 1,. The communication efficiency in the communication lines 2a and 2b is improved.
The message ID, the message classification, and the contents of the relay table 47 in Embodiment 4 and the contents of the transmission timing adjustment processing performed by the ECUs 1, 1,... Are the same as those in Embodiment 1, and are detailed. Description is omitted (see FIGS. 3 to 7).
In the in-vehicle communication system according to the fourth embodiment, the relay device 4 relays a message between the different communication lines 2a and 2b, so even if one communication line 2a can win the transmission by arbitration in the arbitration field, The communication line 2b loses due to arbitration and cannot transmit, and may stay in the temporary storage unit 42 of the relay device 4. In this case, if a message is continuously transmitted from the communication line 2a and is not received by the relay device 4, the message related to the stay can be relayed by several attempts, but the transmission timing is biased and continues. If a message is transmitted to the relay device 4, the stay in the relay device 4 may further increase or deteriorate.
Therefore, in the in-vehicle communication system according to the fourth embodiment, when each of the ECUs 1, 1,... Performs the adjustment process as described above, the relay device 4 determines the retention of the message to be relayed and It is assumed that the ECUs 1, 1,... Are instructed to adjust the transmission timing between the ECUs 1, 1,... And the transmission timing is adjusted between the ECUs 1, 1,.
Hereinafter, a message retention determination process and a transmission timing adjustment instruction process performed by the relay apparatus 4 and a process in each ECU 1, 1,... When an adjustment instruction is issued will be described with reference to flowcharts.
FIG. 17 is a flowchart illustrating an example of a processing procedure when the control unit 40 of the relay device 4 according to the fourth embodiment instructs transmission timing adjustment. The control unit 40 repeats the following processing procedure at regular intervals.
The control unit 40 causes the determination unit 46 to determine whether or not the message stored in the buffer of the temporary storage unit 42 is retained for reception and relaying (step S11). It is determined whether or not it has been determined (step S12). Details of the determination process in step S11 will be described later.
If the control unit 46 determines in step 12 that it is not determined that the message is retained (S12: NO), the control unit 46 ends the process.
When it is determined that the message is staying in step S12 (S12: YES), the control unit 46 specifies the staying message (step S13). At this time, in detail, the control unit 46 specifies the message ID of the message stored at the head of the buffer of the temporary storage unit 42. The control unit 46 controls the first communication unit 44 (or the second communication unit 45) on the communication line 2a (or communication line 2b) side corresponding to the instruction message so that the transmission timing of the message is adjusted between the ECUs 1, 1,. ) (Step S14). The control unit 46 transmits an instruction message in step S13 and transmits information indicating the message specified in step S13, that is, a message ID (step S15), and ends the process.
The control unit 46 repeats the above process. Thus, the instruction message is continuously transmitted while it is determined that the message stays in the relay device 4, that is, until it is determined that the message does not stay.
FIG. 18 is a flowchart illustrating an example of a determination processing procedure for determining whether or not the user is staying, which is executed by the determination unit 46 of the relay device 4 according to the fourth embodiment. The processing procedure shown below is the details of step S11 in the flowchart of FIG.
The control unit 40 receives the message, stores the received message in the buffer of the temporary storage unit 42, and receives the message by the time measuring unit 43 when determining that the message is to be relayed with reference to the relay table 47 of the storage unit 41. Start measuring the elapsed time from the time. The elapsed time measured by the control unit 40 can be referred to by the determination unit 46. Therefore, the determination unit 46 determines whether or not the elapsed time since reception of the message stored in the buffer of the temporary storage unit 42 for reception and relaying is equal to or longer than a predetermined time (step S101). . That is, it is determined whether or not a delay time required for transmission from the transmission source ECU 1 connected to the communication line 2a to transmission from the relay device 4 to the communication line 2b is a predetermined time or more. For example, the predetermined time may be based on the allowable delay time set for each message. In this case, the determination unit 46 may specify the allowable delay time from the message ID of the message stored at the head of the buffer, and determine whether or not the elapsed time exceeds about half of the allowable delay time. .
If the determination unit 46 determines that the elapsed time is equal to or longer than the predetermined time in step S101 (S101: YES), that is, if it is determined that the delay time is long, the determination unit 46 determines that the message stays in the relay device 4. Then (step S102), the process returns to step S12 shown in the flowchart of FIG.
When determining that the elapsed time is less than the predetermined time in step S101 (S101: NO), that is, when determining that the delay time is short, the determining unit 46 determines that the message is not staying (step S103). Then, the process returns to step S12 shown in the flowchart of FIG.
The determination by the determination unit 46 as to whether or not a message is retained is not limited to the processing shown in the flowchart of FIG. FIG. 19 is a flowchart illustrating another example of the determination processing procedure for determining whether or not the user is staying, which is executed by the determination unit 46 of the relay device 4 according to the fourth embodiment.
The determination unit 46 determines whether or not the number of messages stored in the buffer of the temporary storage unit 42 for reception and relaying, that is, the number of unsent messages and stored is a predetermined number or more ( Step S111).
If the determination unit 46 determines that the number of unsent messages is greater than or equal to a predetermined number (S111: YES), the determination unit 46 determines that the message is retained in the relay device 4 (step S112), and is shown in the flowchart of FIG. The process returns to step S12.
If the determination unit 46 determines that the number of unsent messages is less than the predetermined number (S111: NO), the determination unit 46 determines that the messages are not staying (step S113), and proceeds to step S12 shown in the flowchart of FIG. Return processing.
The determination unit 46 performs processing for determining whether or not the message is retained by combining one or both of the processing shown in the flowchart of FIG. 18 and the processing shown in the flowchart of FIG. 19.
When the message to be relayed stays in the relay device 4 by the processing in the relay device 4 as described above, the communication line 2a (or communication line 2b) to which the ECUs 1, 1,. ), An instruction message for instructing adjustment of the transmission timing of the message between the ECUs 1, 1,. When the instruction message is transmitted, each of the ECUs 1, 1,... Connected to the transmitted communication line 2a (or communication line 2b) receives this by the communication unit 13, and basically, as described above. The execution of the transmission timing adjustment process described is started and continued until the transmission of the instruction message is completed (FIG. 7).
Thus, in the in-vehicle communication system according to the fourth embodiment, the ECUs 1, 1,... Connected to the communication lines 2a, 2b mutually perform transmission timing adjustment processing. Collisions are reduced. In particular, when a message stays in the relay device 4, the transmission timing is adjusted so that the message is received almost evenly in the relay device 4. Deterioration can be prevented. Further, the relay device 4 connected to the communication lines 2a, 2b and monitoring the messages transmitted from the ECUs 1, 1,. An instruction message is transmitted at 1,... To adjust the transmission timing. Thus, the ECUs 1, 1,... Only need to perform the adjustment process only when receiving the instruction message, and it is not necessary to perform the process constantly, so that the processing load can be reduced and it is efficient.
In the fourth embodiment, the ECUs 1, 1,... Are configured to mutually adjust the transmission timing when receiving the instruction message so as to eliminate the bias with reference to the master message. In the fifth embodiment, when it is determined that the message is staying in the relay device 4, adjustment is performed so that the transmission timing of the message related to staying and the transmission timing of other messages do not overlap as much as possible.
Since the hardware configuration of the in-vehicle communication system according to the fifth embodiment is the same as that of the fourth embodiment, the same reference numerals are given and detailed description thereof is omitted. Further, since the stay determination process by the determination unit 46 of the relay apparatus 4 is the same, detailed description thereof is omitted. Hereinafter, the instruction message transmission processing procedure by the control unit 40 of the relay apparatus 4 and the transmission timing adjustment processing by the ECUs 1, 1,..., Which are different from the fourth embodiment, will be described.
FIG. 20 is a flowchart illustrating an example of a processing procedure when the control unit 40 of the relay device 4 according to the fifth embodiment instructs transmission timing adjustment. The control unit 40 repeats the following processing procedure at regular intervals. Of the processing procedures shown in the flowchart of FIG. 20, the same processing steps as those shown in FIG. 17 of the fourth embodiment are denoted by the same step numbers, and detailed description thereof is omitted.
The control unit 40 causes the determination unit 46 to determine whether the message is staying (S11), determines whether it is determined that the message is staying (S12), and determines that it is determined that the message is staying. If it has been (S12: YES), the message (message ID) staying is specified (S13). Next, the control part 40 specifies the transmission cycle of the message which concerns on the said residence from message ID (step S16). And the control part 40 transmits an instruction | indication message with the specified transmission period (step S17), transmits the information of message ID of the message which is staying (S15), and complete | finishes a process.
When the control unit 40 determines that it is not determined that it is staying (S12: NO), when the instruction message is periodically transmitted, the control unit 40 stops the transmission of the instruction message (step S18) and ends the process. To do.
In step S17, the control unit 40 transmits the instruction message according to the transmission cycle of the staying message. Thereby, it becomes possible to make other ECU1,1, ... recognize the transmission timing of the message which is staying.
By receiving the instruction message, the ECUs 1, 1,... Basically perform a process of adjusting based on the transmission timing of the master message as described in the fourth embodiment. Further, in the fifth embodiment, the ECUs 1, 1,... Can recognize the transmission timing of the messages that are staying in the instruction message, and adjust the transmission timing based on the transmission timing.
FIG. 21 is a flowchart illustrating an example of a transmission timing adjustment processing procedure based on an instruction message from the ECUs 1, 1,. Each of the ECUs 1, 1,... Repeatedly performs the following processing.
The control part 10 of ECU1 judges whether the message was received by the communication part 13 (step S21). When it is determined that the message has not been received (S21: NO), the control unit 10 returns the process to step S21.
The control unit 10 determines whether or not the received message is an instruction message transmitted from the relay device 4 (step S22). When the control unit 10 determines that the message is not an instruction message (S22: NO), the control unit 10 ends the process, repeats the process from step S21.
If the control unit 10 determines that the received message is an instruction message transmitted from the relay device 4 (S22: YES), the control unit 10 receives information indicating the message ID transmitted together (step S23). Since the instruction message is periodically transmitted according to the transmission period of the staying message while it is determined that the instruction message is staying, the control unit 10 specifies the transmission timing of the instruction message (step S24). .
Next, the control unit 10 determines whether or not the message ID is the message ID of the message transmitted by itself (step S25). When the control unit 10 determines that the message ID is the message ID of the message to be transmitted (S25: YES), the control unit 10 transmits the message by the communication unit 13 so as to approach the transmission timing specified in step S24 (step S26). The process is terminated.
The message ID indicated by the information transmitted together with the instruction message is the message ID of the message staying in the relay device 4. If it is determined in step S25 that the message ID is the message ID transmitted by itself, that is, it is possible to recognize that the message transmitted by itself is retained in the relay device 4. In this case, the relay device 4 transmits an instruction message that serves as a reference for the transmission timing of the staying message so that the ECU 1, 1,... Then, the ECU 1 that transmits the message is transmitting the message related to the stay in accordance with the transmission timing of the instruction message.
When the control unit 10 determines in step S25 that the message ID is not the message ID of the message transmitted by itself (S25: NO), the transmission timing of the message transmitted by itself is determined in step S24. (Step S27), and the process ends.
Specifically, in step S27, the control unit 10 adjusts the transmission timing based on the following grounds. A message is transmitted from each ECU 1, 1,... According to a transmission cycle. After the instruction message is transmitted, the staying message is periodically transmitted from the corresponding ECU 1 starting from the time point when the instruction message is transmitted and the time point in the vicinity thereof by the process of step S25 and step S26 described above. Is done. The other ECUs 1, 1,... Transmit the messages from themselves at a time sufficiently shifted from the timing at which the staying messages are transmitted. It adjusts so that the starting point of its message transmission cycle is shifted with respect to the timing. Specifically, the control unit 10 of the ECUs 1, 1,..., For example, sets a time point that is half the length of its own transmission cycle from the time when the instruction message is transmitted as the starting point of the next transmission cycle. adjust.
In addition, as described in the fourth embodiment, the control unit 10 basically adjusts the master message to be close to the transmission time point of each group and adjusts the master messages to be separated from each other. Also do. Here, when the message transmitted by the control unit 10 belongs to a group in which the staying message is a master, the control unit 10 does not perform a process of bringing the transmission time point closer to the master message. Exceptionally, adjust the transmission time away. As a result, the transmission timing varies more precisely, and the increase and deterioration of stay in the relay device 4 is avoided. For example, since a message transmitted through the communication line 2a has a low priority in the communication line 2b, the message should be relayed by several attempts even if it is not smoothly relayed from the relay device 4. In the meantime, if the message is not transmitted from the other ECUs 1, 1,... Connected to the communication line 2a and the next message is transmitted when the relay of the relatively low priority message is completed, the relay is also efficient. Can be executed.
FIG. 22 is an explanatory diagram schematically showing a specific example of the result of the transmission timing adjustment processing by the ECUs 1, 1,... In the fifth embodiment. In FIG. 22, the horizontal axis indicates the time axis, and the transmission time of each message is indicated by an arrow. It should be noted that the time at which the master message is transmitted is shown on the upper side of the time axis, and the time at which messages other than the master are sent is shown on the lower side.
In the example shown in FIG. 22, the message (hatching arrow) with the message ID “010” is transmitted a plurality of times, and on the left side of FIG. 22, the message of group (1) having the message “010” as the master Has been sent. Specifically, the message IDs are “020” and “180”, respectively. Further, the transmission time point of the message having the message ID “050” is close to the message having the message ID “010”.
For example, it is assumed that a message with a message ID “010” is determined to be staying in the relay device 4 at time t1 in FIG. In this case, an instruction message is transmitted from the relay device 4 and information indicating the message ID “010” of the staying message is transmitted.
The ECU 1 that transmits the message with the message ID “010” transmits the message with the message ID “010” thereafter so as to approach the time t2 when the instruction message is received. Thereafter, the instruction message is transmitted at time points t3 and t4 based on the transmission cycle T of the message whose message ID is “010” until it is determined that the instruction message is not retained. The ECU 1 that transmits the message with the message ID “010” transmits the message with the message ID “010” at a time close to the time t3 and the time t4. The ECU 1 may specify that the instruction message is transmitted in the transmission cycle of the message “010” (transmission timing) starting from the time of reception, and then transmit at the transmission timing.
When receiving the instruction message, the ECUs 1, 1,... That transmit a message whose message ID is not “010” transmit the message away from the time of reception (the time when the instruction message is transmitted). Specifically, the ECU 1 that transmits the message with the message ID “180” adjusts the transmission timing based on the time difference between the time when the message with the message ID “010” as the master is transmitted and its own transmission time. To do. However, the transmission timing should be kept away from the timing at which the instruction message is transmitted. An instruction message reception time point is detected a plurality of times, an instruction message transmission timing start point and a transmission cycle are specified, an adjustment process away from the specified timing, and a transmission timing adjustment process based on the master message transmission time point In the case of conflict, priority is given to the former process.
The ECUs 1, 1,... Determine whether or not the message ID of the message relating to the stay transmitted together with the instruction message matches the message ID of the master of the message group to which the ECU belongs, The adjustment of the transmission timing according to the force F based on the time difference from the transmission time of the master message may not be executed until the instruction message is not transmitted.
Thus, in the example illustrated in FIG. 22, the transmission timing of the message with the message ID “180” is adjusted so that the time difference becomes large even though the message “010” is the master. Thereafter, the timing is further away. Also, for the message with the message ID “020”, the transmission timing is adjusted so that the time difference becomes large after the first instruction message is received even though the message “010” is the master. ing.
In the example illustrated in FIG. 22, the message with the message ID “100” and the message with the message ID “050” are also sufficiently separated from the transmission point of the message with the message ID “010”. It is shown that the transmission timing is adjusted.
In this way, the transmission timing is adjusted mutually by the processing of each ECU 1, 1,. Thereby, the collision of the communication in the communication line 2a is reduced, and communication efficiency improves. Further, since the transmission cycle of the message staying in the relay device 4 can be recognized by the ECUs 1, 1,... That send other messages by sending the instruction message, each ECU 1, 1,. It is possible to adjust the transmission timing so that messages are not transmitted repeatedly until the relay of the existing message is completed, and it is possible to prevent the retention and the deterioration of the message that needs to be relayed in the relay device 4 Thus, the communication efficiency of the entire in-vehicle communication system including the relay device 4 is improved.
In the first to fifth embodiments, the in-vehicle communication system has been described as an example. However, the present invention is not limited to in-vehicle use, but exchanges data among a plurality of communication devices and adjusts transmission timing so that communication between communication devices does not collide in a communication system that operates in cooperation. It is possible to apply to cases.
The disclosed embodiments should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
1 ECU (multiple devices)
2a, 2b Communication line 3 Relay device (communication device)
30 Control Unit 31 Storage Unit 32 Temporary Storage Unit 36 Judgment Unit 4 Relay Device 40 Control Unit 41 Storage Unit 42 Temporary Storage Unit 46 Judgment Unit
In a communication device in which a plurality of devices that transmit and receive messages are connected to a communication line that is connected in a bus shape, and receives a part or all of the message transmitted to the communication line,
Measuring means for measuring the number of messages transmitted during a predetermined monitoring time divided into a plurality of periods;
A determination unit that determines whether or not there is a deviation in transmission timing of messages transmitted by the plurality of devices based on a comparison between the number of messages measured by the measurement unit for each of the plurality of periods;
A communication apparatus comprising: a transmission unit configured to transmit an instruction message for instructing an adjustment for advancing or delaying a transmission timing to the communication line when the determination unit determines that the transmission unit is present.
Means for determining whether or not there is a predetermined number of periods during which no message is transmitted among the plurality of periods;
2. The communication apparatus according to claim 1 , wherein when it is determined that the number of means is equal to or greater than a predetermined number, it is determined that there is a deviation in transmission timing.
Means for determining whether a maximum value of the number of messages in the plurality of periods is equal to or greater than a predetermined multiple of a minimum value;
The communication apparatus according to claim 1 , wherein when it is determined that the means is equal to or greater than a predetermined multiple, it is determined that there is a deviation in transmission timing.
The measuring means is configured to periodically measure the predetermined monitoring time as one period,
Means for determining whether or not the period when the determination means determines that there is no bias in transmission timing continues for a predetermined number of times;
If said means determines that the continuous predetermined number or more, communication according to any one of claims 1 to 3, characterized in that it comprises a means for transmitting a message instructing the stop of the adjustment of the transmission timing to the communication line apparatus.
A means for determining a transmission time point of a message instructing an adjustment for advancing or delaying a transmission timing based on a distribution of the number of messages in each period measured by the measurement unit in the monitoring time;
If it is determined that there is the judgment unit, an instruction message for instructing advancing or delaying adjusting transmission timing, any of claims 1 to 4, characterized in that in the transmission time are to be transmitted to the communication line A communication device according to claim 1.
Each message is sent periodically,
If it is determined that the determination means is provided, the transmission timing of each message whose transmission timing is biased is provided.
The transmission unit, a communication device according to any one of claims 1 to 4, characterized in that the timing corresponding to the specified transmission cycle are so as to transmit the indication message.
The communication device according to any one of claims 1 to 4 , wherein the transmission unit continuously transmits the instruction message until the determination unit determines that there is no transmission.
A plurality of devices that transmit and receive messages, and a plurality of devices connected to a plurality of communication lines that are connected in a bus type, and a part of a message from each device connected to one communication line or In a communication system including a relay device that receives all and relays to a device connected to another communication line,
Measuring means for measuring the number of messages transmitted during a predetermined monitoring time divided into a plurality of periods on one communication line;
Presence / absence of bias in transmission timing of messages transmitted by a plurality of devices connected to the one communication line based on a comparison of the number of messages for each of the plurality of periods measured by the measuring means in the plurality of periods A judging means for judging
A means for transmitting an instruction message for instructing an adjustment for advancing or delaying the transmission timing to each of the plurality of devices when it is determined that the determination means is present;
Means for detecting when a specific message is transmitted when the instruction message is received;
Adjusting means for adjusting the transmission timing of the next own message by advancing or delaying so as to reduce the time difference based on the time difference between the time point when the means detects and the time point when the message is transmitted by itself. A featured communication system.
The relay device specifies a message whose transmission timing is biased;
Means for identifying the transmission period of each identified message,
The transmitting means further includes
The instruction message is transmitted together with message identification information of a message whose transmission timing is biased according to the timing according to the identified transmission cycle,
The adjusting means of the plurality of devices is
Specifying means for specifying the timing at which the instruction message is transmitted;
Determining means for determining whether the message identified by the message identification information transmitted together with the instruction message is a message transmitted by itself;
The communication system according to claim 8 , further comprising: a unit that brings the transmission timing of the message closer to the timing specified by the specifying unit when the determining unit determines that the message is transmitted by itself.
10. The communication system according to claim 9 , further comprising: a unit that moves a transmission timing of the message away from a timing specified by the specifying unit when the determining unit determines that the message is not a message transmitted by the determining unit.
A plurality of devices that transmit and receive messages, and a communication device that is connected to a communication line connected to each of the plurality of devices in a bus type, and that receives a part or all of the message transmitted to the communication line In the communication method between
Measure the number of messages sent during a given monitoring period divided into multiple periods,
Based on the comparison between the measured number of messages for each of the plurality of periods, it is determined whether there is a bias in the transmission timing of the messages transmitted by the plurality of devices,
When it is determined that there is a bias, an instruction message for instructing adjustment to advance or delay transmission timing is transmitted to the plurality of apparatuses via the communication line.
JP2010536685A 2008-11-04 2009-11-03 Communication device, communication system, and communication method Expired - Fee Related JP5111613B2 (en)
JP2008283539 2008-11-04
JP2008283538 2008-11-04
JP2010536685A JP5111613B2 (en) 2008-11-04 2009-11-03 Communication device, communication system, and communication method
PCT/JP2009/005835 WO2010052892A1 (en) 2008-11-04 2009-11-03 Communication device, relay device, communication system, and communication method
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JP2010536685A Expired - Fee Related JP5111613B2 (en) 2008-11-04 2009-11-03 Communication device, communication system, and communication method
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JP (1) JP5111613B2 (en)
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