Communication system, master control device, and slave control device

Abstract

A communication system includes: a central ECU; and a regional ECU that can communicate with the central ECU via a communication bus. The central ECU periodically transmits the count signal including the count value counted each time the count signal is transmitted to the communication bus, transmits a control signal including a start count value and control content to the communication bus, and sets the transmission priority of the count signal to be higher than that of the control signal. The regional ECU receives the count signal and the control signal, and after receiving the control signal, when the count value included in the received count signal is equal to the start count value included in the control signal, starts an operation corresponding to the control content included in the control signal.

Description

Technical Field

[0001] The present invention relates to a communication system, a superior control device, and a subordinate control device. Background Art

[0002] In recent years, there has been research: a regional ECU controls electrical devices within a region according to an instruction from a central ECU through communication between the central ECU (superior control device) and regional ECUs (subordinate control devices) provided in each region of a vehicle.

[0003] In the prior art, as a communication method between ECUs mounted on a vehicle, CAN or CAN-FD of a passive communication method without using a repeater (gateway, etc.) has been used (Patent Documents 1 and 2). In the above CAN or CAN-FD of the passive communication method, in order to ensure a normal communication transmission path, the number of devices connected to the bus and the transmission path length are limited. Therefore, when using the above CAN or CAN-FD for communication between a central ECU and a plurality of regional ECUs distributed in various regions of a vehicle, it is difficult to connect the central ECU and all regional ECUs through one bus.

[0004] Therefore, for example, it is possible to consider providing a left bus provided on the left side of the vehicle and a right bus provided on the right side, connecting the central ECU and the regional ECU provided on the left side of the vehicle through the left bus, and connecting the central ECU and the regional ECU provided on the right side of the vehicle through the right bus. In addition, it is also possible to consider providing a front bus provided on the front side of the vehicle and a rear bus provided on the rear side of the vehicle, connecting the central ECU and the regional ECU provided on the front side of the vehicle through the front bus, and connecting the central ECU and the regional ECU provided on the rear side of the vehicle through the rear bus.

[0005] The regional ECU operates according to a control signal transmitted from the central ECU via the bus, but when the bus is in a high-load state, the control signal waits and there is a transmission delay. Therefore, when the bus is provided on the front and rear sides or the left and right sides, there is a problem of operation timing deviation due to the transmission timing deviation of the control signal between the regional ECUs of different buses. Therefore, the illumination of the front and rear turn signals and the left and right turn signals may be different, and the control timing of the front and rear brake actuators may also deviate.

[0006] Citation List

[0007] Patent Documents

[0008] Patent Document 1: JP-2002-261780-A;

[0009] Patent Document 2: JP-2002-254996-A. Summary of the Invention

[0010] The present invention is made in view of the above circumstances, and an object of the present invention is to provide a communication system, a master control device, and a slave control device that can prevent a deviation in the operation start timing between slave control devices connected to different buses.

[0011] In order to achieve the above object, the communication system, the master control device, and the slave control device according to the present invention are characterized as follows.

[0012] A communication system according to the present invention includes: a master control device; a first slave control device capable of communicating with the master control device via a first bus; and a second slave control device capable of communicating with the master control device via a second bus. The master control device includes: a first transmission unit configured to periodically transmit a count signal to the first bus and the second bus, the count signal including a count value that increments each time the count signal is transmitted; and a second transmission unit configured to transmit a control signal including a start count value and control content to the first bus and the second bus. The transmission priority of the count signal is set higher than the transmission priority of the control signal. The first slave control device and the second slave control device include a first reception unit configured to receive the count signal and a second reception unit configured to receive the control signal. After receiving the control signal, when the count value included in the received count signal becomes equal to the start count value included in the control signal, an operation corresponding to the control content included in the control signal is started.

[0013] In addition, a master control device according to the present invention can communicate with a first slave control device via a first bus and can communicate with a second slave control device via a second bus. The master control device includes: a first transmission unit configured to periodically transmit a count signal to the first bus and the second bus, the count signal including a count value that increments each time the count signal is transmitted; and a second transmission unit configured to transmit a control signal including a start count value and control content to the first bus and the second bus. The transmission priority of the count signal is set higher than the transmission priority of the control signal.

[0014] A slave control device according to the present invention is capable of communicating with a master control device. The slave control device includes: a first receiving unit configured to receive a reception count signal from the priority master control device, the count signal including a count value that increments each time the count signal is transmitted; and a second receiving unit configured to receive a control signal from the priority master control device, the control signal including a start count value and control content. After receiving the control signal, when the count value included in the received count signal becomes equal to the start count value included in the control signal, an operation corresponding to the control content included in the control signal is started.

[0015] The present invention has been briefly described above. In addition, details of the present invention will be described by reading aspects for implementing the invention to be described below (hereinafter, referred to as "embodiments") with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a block diagram showing an embodiment of a communication system according to the present invention.

[0017] Figure 2A is a diagram showing the frame structure of a count signal, and Figure 2B is a diagram showing the frame structure of a control signal.

[0018] Figure 3 is a diagram showing signals transmitted by Figure 1 shown central ECU and a table of IDs assigned to the signals.

[0019] Figure 4 is used to represent Figure 1 the timing diagram of the operation of the communication system shown. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, specific embodiments according to the present invention will be described with reference to the drawings.

[0021] Figure 1 is a block diagram showing an embodiment of a communication system 1 according to the present invention. The communication system 1 according to this embodiment is installed in a vehicle 100. The communication system 1 includes a plurality of communication buses B1 (first bus), communication bus B2 (second bus), a central ECU 2 (master control device), a plurality of area ECUs 31 to 34 (first slave control devices), and a plurality of area ECUs 41 to 44 (second slave control devices).

[0022] For example, a plurality of communication buses B1 and B2 are connected between a central ECU2 provided in the instrument panel of the vehicle 100 and area ECUs 31 to 34 and 41 to 44 provided in respective areas of the vehicle 100. In the present embodiment, the communication bus B1 is connected between the central ECU2 and the plurality of area ECUs 31 to 34 provided in the left area of the vehicle 100. The communication bus B2 is connected between the central ECU2 and the plurality of area ECUs 41 to 44 provided in the right area of the vehicle 100.

[0023] In the present embodiment, an example in which the communication buses B1 and B2 are provided corresponding to the left and right areas will be described, but the present invention is not limited thereto. The communication buses B1 and B2 may be provided corresponding to respective areas of the vehicle 100. For example, the vehicle 100 may be divided into a front area and a rear area, and the central ECU2 and the area ECUs 31 to 34 provided in the front area may be connected through the communication bus B1 corresponding to the front area, and the central ECU2 and the area ECUs 41 to 44 provided in the rear area may be connected through the communication bus B2 corresponding to the rear area.

[0024] The central ECU2 includes a microcomputer having a CPU and controls the entire communication system 1.

[0025] A plurality of area ECUs 31 to 34 are provided in the left area of the vehicle 100. A plurality of area ECUs 41 to 44 are provided in the right area of the vehicle 100. In the present embodiment, the area ECUs 31 and 41 are provided on the front side of the vehicle 100, the area ECUs 32, 34, 42, and 44 are provided near the door on the driver's seat side of the vehicle 100, and the area ECUs 33 and 43 are provided on the rear side of the vehicle 100.

[0026] The area ECUs 31 to 34 and 41 to 44 communicate with the central ECU2 and control the lights 51 to 53 and 61 to 63 provided in respective areas according to control signals transmitted from the central ECU2. The lights 51 to 53 are provided in the left area of the vehicle 100. The lights 61 to 63 are provided in the right area of the vehicle 100. The lights 51 and 61 are provided side by side on the front side of the vehicle 100 and are turned on and off simultaneously. The lights 52 and 62 are respectively provided on the left and right side mirrors and are turned on and off simultaneously. The lights 53 and 63 are provided side by side on the rear side of the vehicle 100 and are turned on and off simultaneously.

[0027] The lights 51 to 53 are respectively connected to and controlled by the area ECUs 31 to 33. The lights 61 to 63 are respectively connected to and controlled by the area ECUs 41 to 43. In Figure 1 the example shown, in addition to the lights 51 to 53 and 61 to 63, the area ECUs 31 to 33 and 41 to 43 are also connected to the powertrain system electrical devices and the chassis system electrical devices.

[0028] The communication system 1 according to the present embodiment adopts a multi-master system, in which equal bus access can be implemented in the central ECU 2 and the regional ECUs 31 to 34 and 41 to 44. In the multi-master system, the central ECU 2 and the regional ECUs 31 to 34 and 41 to 44 determine whether other ECUs are performing signal transmission to the communication buses B1 and B2 based on the voltage levels of the communication buses B1 and B2. When other ECUs are not performing signal transmission, the central ECU 2 and the regional ECUs 31 to 34 and 41 to 44 transmit signals, and when other ECUs are performing signal transmission, the central ECU 2 and the regional ECUs 31 to 34 and 41 to 44 wait until the signal transmission is completed and then transmit signals.

[0029] In addition, the communication system 1 according to the present embodiment adopts CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance), so that multiple ECUs 2, 31 to 34 and 41 to 44 can transmit signals to the communication buses B1 and B2 simultaneously, thereby preventing signals from colliding with each other. In CSMA / CA, the ECUs 2, 31 to 34 and 41 to 44 assign IDs indicating transmission priorities to the signals to be transmitted. When signals assigned with IDs having higher transmission priorities than those of the ECUs 2, 31 to 34, 41 to 44 are transmitted simultaneously, the ECUs 2, 31 to 34 and 41 to 44 stop signal transmission based on the voltage levels of the communication buses B1 and B2. Therefore, the signals assigned with IDs having higher transmission priorities are preferentially transmitted to the communication buses B1 and B2.

[0030] More specifically, the ECUs 2, 31 to 34 and 41 to 44 transmit signals including "0: dominant (superior)" and "1: recessive (inferior)". In the communication buses B1 and B2, when signals including "0" and "1" are transmitted simultaneously, the signal level corresponds to "0". Therefore, as Figure 3 shown, the ID with all bits being "0" is the ID with the highest priority, and the ID with all bits being "1" is the ID with the lowest transmission priority. For example, when an ID with all bits being "1" and an ID with all bits being "0" are transmitted simultaneously, the ID with all bits being "0" is preferentially transmitted in the communication buses B1 and B2. When the signal transmitted during ID transmission does not match the signal level of the communication buses B1 and B2, the ECUs 2, 31 to 34 and 41 to 44 determine that signals assigned with higher transmission priorities than those of the ECUs 2, 31 to 34 and 41 to 44 are transmitted simultaneously, and stop signal transmission.

[0031] Next, the signals transmitted by the central ECU 2 will be described. The central ECU 2 functions as a first transmission unit and periodically transmits count signals to the communication buses B1 and B2. The frame structure of the count signals will be described with reference to Figure 2A As Figure 2AAs shown, the count signal includes a data header, a data area, and a data tail, and the time count value is included in the data area. Each time the central ECU 2 transmits a count signal, the central ECU 2 increments the time count value. The data header of the count signal includes an ID indicating the transmission priority. In this embodiment, as Figure 3 shown, an ID with all bits of "0" having the highest priority is assigned as the ID of the count signal.

[0032] In addition, the central ECU 2 functions as a second transmission unit and transmits control signals for controlling the area ECUs 31 to 34 and 41 to 44. Among the control signals, for example, the lamp control signals output to the area ECUs 31 to 34 and 41 to 44 that are connected to different communication buses B1 and B2 and need to operate simultaneously include a data header, a data area, and a data tail, and the control content (turning on the lamp) and the start count value are included in the data area. The data header of the lamp control signal includes an ID indicating the transmission priority. In this embodiment, as Figure 3 shown, the ID of the lamp control signal is assigned an ID with a lower transmission priority than the powertrain-related control signals for controlling the electrical devices of the powertrain system and the chassis-system-related control signals for controlling the electrical devices of the chassis system. The central ECU 2 transmits the lamp control signals to the two communication buses B1 and B2.

[0033] The central ECU 2 causes the control signal to include a start count value that has a shorter difference from the time count value included in the count signal just transmitted before as the transmission priority of the ID included in the control signal is higher. Specifically, when the time count value just transmitted before is 100, 105 is included as the start count value in the powertrain-related control signal with a higher transmission priority, and 110 is included as the start count value in the lamp control signal with a lower transmission priority. Therefore, the control content included in the control signal including the ID with a higher transmission priority can be executed quickly.

[0034] On the other hand, the area ECUs 31 to 33 and 41 to 43 connected to the lamps 51 to 53 and 61 to 63 function as a first receiving unit and a second receiving unit, and receive the count signal and the lamp control signal. After the area ECUs 31 to 33 and 41 to 43 receive the lamp control signal, when the count value included in the received count signal becomes equal to the start count value included in the control signal, the area ECUs 31 to 33 and 41 to 43 turn on the lamps 51 to 53 and 61 to 63 according to the control content included in the lamp control signal.

[0035] Next, the operation of the above communication system 1 will be described with reference to the Figure 4 timing diagram. As Figure 4As shown, the central ECU2 periodically transmits count signals to communication buses B1 and B2. Since the count signals have the highest-priority ID, the count signals can be transmitted to communication buses B1 and B2 with the highest priority. Therefore, as Figure 4 shown, there is almost no transmission deviation of the count signals between communication buses B1 and B2.

[0036] When the central ECU2 determines that the hazard lighting instruction is issued by the driver, the central ECU2 transmits a lamp control signal to communication buses B1 and B2. In the Figure 4 example shown, since communication bus B1 is not in use, the central ECU2 can immediately transmit the lamp control signal to communication bus B1. At the same time, since another control signal is being transmitted in communication bus B2, the central ECU2 waits until the transmission of the corresponding other control signal is completed and then transmits the lamp control signal. After that, in the Figure 4 example shown, since a control signal with a higher transmission priority than the lamp control signal in terms of its ID is being transmitted simultaneously, the central ECU2 can transmit the lamp control signal by further waiting until the transmission of the control signal is completed. Therefore, there is a large transmission deviation of the lamp control signal between communication buses B1 and B2.

[0037] However, 110 is written as the start count value in the lamp control signal. Therefore, after receiving the count signal in which "110" is written as the count value, the regional ECUs 31 to 33 and 41 to 43 turn on lamps 51 to 53 and 61 to 63 according to the control content included in the control signal. In this way, there is almost no transmission deviation of the count signals between communication buses B1 and B2. Therefore, it is possible to prevent a deviation in the lighting start timing between lamps 51 to 53 provided on the left side and lamps 61 to 63 provided on the right side.

[0038] The present invention is not limited to the above embodiments and can be appropriately modified, improved, etc. In addition, as long as the object of the present invention can be achieved, the materials, shapes, dimensions, quantities, arrangement positions, etc. of the components in the above embodiments are optional and not limited.

[0039] In the above embodiments, the ID of the count signal is set to the ID with the highest priority, but the present invention is not limited thereto. The ID of the count signal can have a higher transmission priority than the ID of the lamp control signal. The higher the transmission priority of the ID, the smaller the transmission deviation from communication buses B1 and B2. Therefore, in the above embodiments, when the ID of the count signal is given the highest priority, it is possible to maximally prevent a deviation in the lighting timing of lamps 51 to 53 and 61 to 63. However, even when the ID is not given the highest priority, if the transmission priority is higher than the ID of the lamp control signal, it is also possible to prevent a deviation in the lighting timing of lamps 51 to 53 and 61 to 63.

[0040] In the above-described embodiment, the communication system 1 includes two communication buses B1 and B2, but the present invention is not limited thereto. The communication system 1 may also include three or more communication buses B1 and B2.

[0041] In the above-described embodiment, the area ECUs 31 to 33 and 41 to 43 control the lamps 51 to 53 and 61 to 63, but the present invention is not limited thereto. The electrical devices connected to the area ECUs 31 to 33 and 41 to 43 may be front and rear brake actuators or the like.

[0042] Here, the features of the communication system, the master control device, and the slave control device according to the above-described embodiments of the present invention will be briefly summarized and listed in [1] to [5] below. [1]

[0044] A communication system (1) comprising:

[0045] A master control device (2);

[0046] A first slave control device (31 to 34) capable of communicating with the master control device (2) via a first bus (B1); and

[0047] A second slave control device (41 to 44) capable of communicating with the master control device (2) via a second bus (B2).

[0048] The master control device (2) includes:

[0049] A first transmission unit (2) configured to periodically transmit a count signal to the first bus (B1) and the second bus (B2), the count signal including a count value that increments each time the count signal is transmitted, and

[0050] A second transmission unit (2) configured to transmit a control signal including a start count value and control content to the first bus (B1) and the second bus (B2).

[0051] The transmission priority of the count signal is set higher than the transmission priority of the control signal.

[0052] The first slave control device (31 to 34) and the second slave control device (41 to 44) include:

[0053] A first reception unit (31 to 34, 41 to 44) that receives the count signal; and

[0054] A second reception unit (31 to 34, 41 to 44) that receives the control signal.

[0055] After receiving the control signal, when the count value included in the received count signal becomes equal to the start count value included in the control signal, an operation corresponding to the control content included in the control signal is started. [2]

[0057] The communication system (1) according to [1],

[0058] The upper control device (2) causes the count signal to be transmitted to the first bus (B1) and the second bus (B2) with the highest priority. [3]

[0060] The communication system (1) according to [1] or [2],

[0061] The upper control device (2) causes the control signal to include the start count value having a shorter difference from the count value in the count signal just transmitted before as the transmission priority of the control signal is higher, and transmits the control signal. [4]

[0063] An upper control device (2) capable of communicating with a first subordinate control device (31 to 34) via a first bus (B1) and capable of communicating with a second subordinate control device (41 to 44) via a second bus (B2), the upper control device (2) includes:

[0064] A first transmission unit (2) configured to periodically transmit a count signal to the first bus (B1) and the second bus (B2), the count signal including a count value that is incremented each time the count signal is transmitted; and

[0065] A second transmission unit (2) configured to transmit a control signal including a start count value and control content to the first bus (B1) and the second bus (B2).

[0066] The transmission priority of the count signal is set higher than the transmission priority of the control signal. [5]

[0068] A subordinate control device (31 to 34, 41 to 44) capable of communicating with an upper control device (2), the subordinate control device (31 to 34, 41 to 44) includes:

[0069] A first receiving unit (31 to 34, 41 to 44) configured to receive a count signal from the upper control device (2), the count signal including a count value that is incremented each time the count signal is transmitted; and

[0070] Second receiving units (31 to 34, 41 to 44), configured to receive a control signal including a start count value and control content from the upper control device (2).

[0071] After receiving the control signal, when the count value included in the received count signal becomes equal to the start count value included in the control signal, start an operation corresponding to the control content included in the control signal.

[0072] According to the communication system having configuration [1], when the count value of the count signal with a higher transmission priority becomes the start value count value included in the control signal, the first and second subordinate control devices start operations according to the control content included in the control signal. Therefore, it is possible to prevent a deviation in the operation start timing between the first and second subordinate control devices.

[0073] According to the communication system having configuration [2], the upper control device transmits the count signal to the first bus and the second bus with the highest priority. Therefore, it is possible to further prevent a deviation in the operation start timing between the first and second subordinate control devices.

[0074] According to the communication system having configuration [3], the control content included in the control signal with a transmission priority can be executed quickly.

[0075] According to the upper control device having configuration [4], a count signal including a count value that increments each time the count signal is transmitted is periodically transmitted to the first and second buses, and a control signal including a start count value and control content is transmitted to the first and second buses. Therefore, when the count value of the count signal becomes the start count value included in the control signal, the subordinate control devices connected to the first and second buses can start operations according to the control content included in the control signal. Therefore, it is possible to prevent a deviation in the operation start timing between the first and second subordinate control devices.

[0076] According to the subordinate control device having configuration [5], after receiving the control signal, when the count value included in the received count signal becomes equal to the start count value included in the control signal, start an operation corresponding to the control content included in the control signal. Therefore, it is possible to prevent a deviation in the operation start timing between the subordinate control devices connected to different buses.

[0077] According to the present invention, it is possible to provide a communication system, an upper control device, and a subordinate control device capable of preventing a deviation in the operation start timing between subordinate control devices connected to different buses.

Claims

1. A communication system, comprising: A superior control device; A first subordinate control device capable of communicating with the superior control device via a first bus; And A second subordinate control device capable of communicating with the superior control device via a second bus, Wherein, the superior control device includes A first transmission unit configured to periodically transmit a count signal to the first bus and the second bus, the count signal including a count value that increments with each transmission of the count signal, and A second transmission unit configured to transmit a control signal including a start count value and control content to the first bus and the second bus, Wherein, the transmission priority of the count signal is set higher than the transmission priority of the control signal, Wherein, the first subordinate control device and the second subordinate control device include a first receiving unit configured to receive the count signal and a second receiving unit configured to receive the control signal, and Wherein, after receiving the control signal, when the count value included in the received count signal becomes equal to the start count value included in the control signal, an operation corresponding to the control content included in the control signal is started, Wherein, the superior control device causes the control signal to include the start count value having a shorter difference from the count value in the count signal just transmitted before as the transmission priority of the control signal is higher, and transmits the control signal.

2. The communication system according to claim 1, Among them, The superior control device causes the count signal to be transmitted to the first bus and the second bus with the highest priority.

3. A superior control device capable of communicating with a first subordinate control device via a first bus and capable of communicating with a second subordinate control device via a second bus, the superior control device comprising: A first transmission unit configured to periodically transmit a count signal to the first bus and the second bus, the count signal including a count value that increments with each transmission of the count signal; And A second transmission unit configured to transmit a control signal including a start count value and control content to the first bus and the second bus, Wherein, the transmission priority of the count signal is set higher than the transmission priority of the control signal, Wherein, the superior control device causes the control signal to include the start count value having a shorter difference from the count value in the count signal just transmitted before as the transmission priority of the control signal is higher, and transmits the control signal.

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