JP2933972B2 - Multiplex transmission equipment for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multiplex transmission system for a vehicle in which a multiplex transmission system such as a CSMA / CD system is applied to signal transmission in a vehicle, and more particularly to a distributed transmission system for the vehicle. The present invention relates to a vehicle transmission device integrating a multiplex communication network and a parallel bus line.

(Prior Art) With the development of electronics in automobiles, the enlargement and complexity of wiring (wire harness) connecting electronic components has become a serious problem. In order to solve this problem, especially in the field of automobiles, multiplex communication has attracted attention. The multiplex communication is to transmit a plurality of data in a time-division multiplex on one wiring, and is basically based on serial transmission.

In the field of automobiles, the network form of the multiplex communication is considered to be classified into a complete multiplex type and a partial multiplex type, or a centralized type and a distributed type. The partial multiplexing type is a mixture of a non-multiplexing communication part and a multiplex communication part. In the multiplex communication part, switches, loads, and the like, which are distributed in a distance, are connected by a multiplex transmission unit. It is said that individual wiring is required between the unit, switch and load, so that the total length of the wiring is reduced, but the number is increased. In the centralized type, the transmission unit of a plurality of slaves is connected to the transmission unit of one master. Although the effect of reducing the diameter can be obtained, the system goes down when the master goes down, and design changes are required. It is said that there are drawbacks such as difficulty. On the other hand, although the dispersion type is expensive, it has been spotlighted in that a large diameter reduction effect can be obtained, reliability for partial down is high, flexibility for design change is high, and the like (for example, JP 62-4658
issue).

In this distributed multiplex communication system, for example, the CSMA / CD system is adopted in a standardization plan of the American Society of Automotive Engineers (SAE).

In addition, the present applicant has reported that PALMNET (Protocol for Automobile Local area Ne
A twork) system has also been proposed as Japanese Patent Application No. 62-302421.

In Japanese Patent Application Laid-Open No. 1-36541 by the present applicant, a master node sets a channel on a transmission line and sends a reference pulse for time-dividing a bus access right.

(Problems to be Solved by the Invention) In recent multiplex communication systems for vehicles, it has been proposed to connect controllers (engine controller, traction controller, and the like) in a narrow sense by multiplex communication. Since the frequency of the data to be transmitted and the data required by itself is quite high, the communication nodes for these controllers are provided for electrical components such as actuators (motors, etc.) and sensors. When nodes and nodes are mixed, the communication speed of the entire system must be set to a high value, which has caused a cost increase.

On the other hand, with the advancement of controls such as traction control, rear wheel steering control, and ABS control, these controls not only require high-speed processing, but also information data used between these controllers includes: These controllers are closely related to each other. In other words, the exchange of information between these controllers has become indispensable. In other words, it is time to reconfigure the system considering such controllers as one group.

The present invention has been made based on such a background, and an object of the present invention is to efficiently and inexpensively transmit a vehicle state signal collected by a sensor for the purpose of controlling a vehicle to another communication node. To provide a multiplex transmission device for vehicles.

(Means and Actions for Achieving the Object) A vehicle for transmitting a state signal collected by one sensor communication node to a plurality of other communication nodes for the purpose of vehicle control according to the present invention for achieving the above object. The multiplex transmission device includes a serial bus line provided for communication, a parallel bus line provided for data transfer, a RAM node connected to the parallel bus line, and a serial bus connected to the parallel bus line. A communication node connected to the bus line, wherein the first sensor communication node detects a predetermined state of the vehicle and sends the state to the serial bus line as a state signal; and the serial bus line and the parallel bus line. And the first state signal from the first sensor communication node is transmitted to the serial bus line. In receiving, the purpose, the first for controlling the vehicle
A second communication node that processes the status signal to convert it into a second status signal, and writes the second status signal to the RAM node via the parallel bus line; And a third communication node connected to the RAM node for reading the second state signal from the RAM node via the parallel bus line for controlling the vehicle. .

According to the multiplex transmission device for a vehicle having such a configuration, the first state signal relating to the vehicle state collected by the sensor communication node is transmitted to both the second and third communication nodes by a single transmission to the serial bus line. . In this case, it is transmitted directly to the second communication node via the serial bus line, where it is processed into this second state signal and used at the second communication node for vehicle control purposes. . On the other hand, the second state signal obtained by this processing is transmitted to the third communication node via the parallel bus line and the RA.
It is transmitted indirectly via the M-node, where it is used for vehicle control purposes. For example, vehicle speed data and the like are required by a plurality of communication nodes. However, the sensor node cannot detect the vehicle speed data itself. For example, a predetermined signal is obtained from a rotation signal (that is, a first state signal). Vehicle speed data (second state signal) is generated using the calculation.
The third communication node can obtain the second vehicle state data without performing the operation.

According to a preferred embodiment of the present invention, the third communication node is further connected to the serial bus line.

The third communication node needs to know the timing when the signal is stored in the RAM node. Therefore, according to claim 3, which is a preferable aspect of the present invention, the second communication node and the third communication node have an interrupt control function, and the second communication node transmits the status signal. Is written to the RAM node via the parallel bus line, the third communication node is interrupted, and when the third communication node is interrupted by the second communication node, The state data is read from the RAM node.

On the other hand, in order to know the timing, according to claim 4, which is a preferred embodiment of the present invention, the RAM node indicates a storage area for storing a state signal and that the state signal is stored. A storage area for storing a flag, wherein the third communication node checks the flag area at a predetermined timing to confirm the presence / absence of a newly stored state signal.

(Embodiment) The present invention will now be described with reference to the accompanying drawings.
An example in which the present invention is applied to a multiplex communication apparatus for a vehicle using the system will be described.

FIG. 1 shows the configuration of this embodiment. In the figure, reference numeral 1 denotes a transmission line, which uses a twisted pair line. The communication speed was 20 kbps. Two to ten nodes are connected on this transmission line 1. 11a and 11b are parallel bus lines, where 11a is a data bus and 11b is a control bus (address line, interrupt line, memory control signal line).

The bus 11 includes an active suspension controller (MACS) node 10, a rear wheel steering controller (4WS) node 8, an ABS node 7 including a controller for anti-lock brake control, and an engine control A node 6 for a controller (EGI) is connected.

In FIG. 1, the sensor node 2 is, for example, a node to which a sensor for detecting an acceleration in a vertical movement direction required for active suspension control is connected. The actuator node 3 is, for example, a motor for rear wheel steering. The sensor node 4 is for a sensor for measuring the wheel speed. The actuator node 5 is a traction control motor.

For convenience, a node that requires cooperative control that is closely related to each other (often uses common data), such as an ABS / TRC controller or 4WS controller, is called a controller node, and is used for passive elements such as sensors and actuators. The node is called a body node.

Reference numeral 9 denotes a RAM device, which is connected to the bus 11. That is, data can be written to and read from the RAM 9 from the nodes 6 to 10.

As a method of using the RAM 9, for example, the ABS / TRC node 7 receives data from the wheel speed sensor 4, calculates the wheel speed, and stores the calculated wheel speed at a predetermined position on the RAM 9. If this wheel speed data is also required at EGI node 6, ABS / TRC
Node 7 interrupts the EGI node to indicate that data has been stored in RAM 9. The interrupted EGI node reads the wheel speed data in the RAM 9. After calculating the vehicle speed from the wheel speed data, the EGI node calculates a fuel injection amount, for example, and sends the fuel injection amount data to a node (not shown) having a fuel injection valve (not shown).

FIG. 2 shows a configuration of a communication node for an EGI controller as an example. Each node is connected to the transmission line 1 via the communication LSI 21. Further, it is connected to the parallel bus 11 via the bus interface 24. Reference numeral 20 denotes a control CPU which operates according to a program stored in the RAM / ROM 22. An interrupt controller 23 detects an interrupt from another node and sends a control command to the CPU 20 according to the interrupt. The physical layer level protocol control of the CSMA / CD system is performed by the LSI 21. The CPU 20 controls the LSI 21 and processes data from the LSI and transfers the data to the EGI controller, or
Control for transferring data from the controller to the LSI 21 is performed.

The interface 24 and the interrupt controller 23 shown in FIG. 1 are not required for the sensor and actuator nodes shown in FIG.

In the multiplex transmission system for vehicles of this embodiment, vehicle driving information is transmitted for each frame F having a configuration as shown in FIG.

The frame F has a frame structure including an SD (Start Delimiter) code, a priority code, a frame ID code, a data length, data 1 to data N, and a check code.

First, the “SD code” is a specific code indicating the start of the frame F, and the receiving multiplex node recognizes the start of the frame F when receiving the SD code code. The "priority code" is a code indicating a priority order that indicates which signal should be processed with priority when a plurality of multiplex nodes transmit data at the same time and signals collide. In this embodiment, the lower the priority is, the higher the priority is assigned. This is because the low level of the bus 1 is WIRED-OR. If a signal is sent from a plurality of nodes at the same time, the "priority code" of the node with the higher priority remains on the bus 1, and the lower node uses the "priority code" transmitted by itself as another code. , The collision is detected. Then, by delaying the retransmission of its own failed frame, retransmission from a node with a higher priority is given priority.

“Frame ID code” is a code indicating the transmission source of the frame. In the fail notification frame according to the present embodiment, the ID is unified to “01” regardless of the failure notification frame from any node. Information on which node has failed is stored in a subsequent data bit (DA
TA).

In the “data length”, the number of data that follows is written. If there are N data, N is sent as the data length. At the multiplex node receiving this frame,
Reads only the data length. The field following the data is the CRC check code (error detection code). By confirming this, it is possible to know that the end of the frame has been reached. The format shown in FIG. 3 shows a general format, and the data length of the frame used in this embodiment is unified to 4 bytes.

FIG. 4 is a diagram showing a controller node (EG) shown in FIG.
FIG. 3 illustrates sensors and actuators necessary for I nodes, ABS / TRC nodes, 4WS nodes, and ASC nodes) and the locations of the nodes.

In FIG. 4, the four controller nodes are interconnected by a parallel bus 11. These four controller nodes are also connected to the serial bus 1. In FIG. 4, 30 is a vehicle height sensor node for ACS, and 31 is ACS.
Hydraulic open / close valve node, 32 is a wheel speed sensor, 33 is
ABS / TRC brake pressure adjustment valve node, 34 is a steering wheel angle sensor, 35 is a rear wheel steering angle sensor node for rear wheel steering control, 37 is a motor node for 4WS, 35 is an acceleration sensor node for ACS , 39 are fuel injector nodes. These “body” nodes are connected to the serial bus 1. 36 is a rear wheel steering device.

Fig. 5 shows the serial bus 1 in the "body" node.
7 is a flowchart showing a data transfer control procedure of the first embodiment.
In step S2, the SD indicating the beginning of the frame on the transmission path 1
Check if is detected. If the SD is detected, the frame is received and the data contained in the frame is processed. If there is no frame on the transmission path 1, it is checked in step S8 whether or not there is data to be transmitted. If there is transmission data, the frame is transmitted onto the serial bus 1.

FIG. 6 shows a parallel bus in a controller node.
11 is a flowchart illustrating data transfer control with the serial bus 11 and data transfer control with the serial bus 1. Step S20
Now check if there was an interrupt. This interrupt includes:
There is an interrupt from the LSI 21 when an SD is detected on the serial transmission line 1 and an interrupt from another controller node (indicating that data has been written to the RAM 9).

If the other controller node is an interrupt indicating that the data for the node has been written to the RAM 9, the data is read from the RAM 9 in step S24.
In step S26, the data is processed. This "data processing" includes creation of frame data to be sent to another body node and creation of data to be written to the RAM 9.

If the interrupt is due to SD detection, step S28
Step S30 is executed to receive the frame and perform "data processing".

If it is determined in step S20 that there is no interrupt,
In step S32, it is checked whether there is data to be transmitted to another node or the RAM 9. If the data is to be transmitted on the serial bus 1 as a frame, the frame is transmitted in step S36. Transmission data is RAM9
Then, after confirming that the parallel bus 11 is not busy, the data is written to the RAM 9 in step S40. Then, in step S42, an interrupt is issued to the controller node to which the data is to be sent. This interrupt writes the node address of the destination to the address bus on the control bus 11b, and places the RAM 9 on the data bus 11a.
Write the storage address in

As described above, according to the above-described embodiment, since: the controller nodes that often require cooperative control are connected not only by the serial bus but also by the parallel bus, Can be performed at high speed. The main task of these controller nodes is data processing.
The installation position is relatively unimportant compared to the body node. This is because the body nodes need to be located in the vicinity of the sensors and actuators in order to directly relate to them. In the above embodiment, the property that the installation positions of the controller nodes are relatively insignificant is skillfully used, and these nodes are connected by a high-speed parallel bus that needs to be arranged close to each other. .

: Further, since data is transferred between these controller nodes, the shared memory 9 is used, so that data transfer is efficient. This is because one piece of data written in the RAM 9 can be referred to by a plurality of controller nodes.

The controller nodes, which often require cooperative control, are interconnected by a high-speed parallel bus 11, and the body nodes and the body nodes and the controller nodes are connected by a serial bus. Therefore, a relatively low communication speed of the serial bus 1 is sufficient.

The present invention can be variously modified without departing from the gist thereof.

For example, the number of nodes is not limited to the number described above.

Further, in the above embodiment, the notification of the end of the data writing to the RAM 9 is performed by interruption, but may be changed as follows. That is, a flag indicating that the data has been updated is provided in the RAM 9 in addition to the data area. Then, the receiving node periodically checks the flag and, if there is updated data, takes in the data.

Further, the following modification is proposed. For example, ABS / TRC
The control procedure has a lot in common with the ABS control and the 4WS control. Therefore, when a certain controller has a large data processing load, another controller can access data in the RAM 9 and perform data processing in place of the busy controller. By performing such parallel distributed processing, multiplexing of the control system can be prevented.

(Effect of the Invention) As described above, according to the multiplex transmission apparatus for a vehicle according to the first aspect of the present invention, the vehicle state signal collected by the first sensor communication node for the purpose of controlling the vehicle is transmitted. It is possible to transmit to other communication nodes (the second communication node and the third communication node) efficiently and at low cost. In particular, when the second state signal is needed at both the second communication node and the third communication node, the third communication node does not perform the operation for obtaining the second state signal. It can be obtained and contributes to the low cost of the third communication node.

Further, according to the multiplex transmission apparatus for a vehicle of the third aspect, by using the interrupt, the third communication node can surely read the state data.

According to the multiplex transmission apparatus for a vehicle of the fourth aspect, by using the flag indicating that the state signal is stored, the third communication node can reliably read the state data.

[Brief description of the drawings]

FIG. 1 is a diagram showing a network configuration of an embodiment to which the present invention is applied, FIG. 2 is a block diagram showing a hardware configuration of a controller system node used in the embodiment, and FIG. 3 is a frame used in the embodiment. FIG. 4 is a diagram specifically showing an installation position of each node, and FIGS. 5 and 6 are flowcharts showing a control procedure according to the embodiment. In the figure, 1 ... a serial transmission line, 2 ... a sensor node, 3 ... an actuator node, 4 ... a wheel speed sensor node, 5
…… Actuator node, 6 …… EGI node, 7 …… A
BS / TRC node, 8 ... 4WS node, 9 ... RAM, 10 ... AC
S node, 11 ... Parallel bus, 11a ... Data bus, 11b ...
... Control bus, 20 ... CPU, 21 ... Communication LSI, 22 ... RAM /
ROM, 23 interrupt controller, 24 bus interface, 30 vehicle height sensor node for ACS, 31 A
Hydraulic opening / closing valve node for CS, 32 …… wheel speed sensor node, 33 …… node for ABS / TRC brake pressure adjusting valve, 3
4 ... steering wheel steering angle sensor node, 35 ... rear wheel steering angle sensor node, 36 ... rear wheel steering device, 37 ... motor node for 4WS, 38 ... acceleration sensor node for ACS, 39 ... fuel It is an injection valve node.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-222953 (JP, A) JP-A-64-27025 (JP, A) JP-A-1-36541 (JP, A) JP-A 61-221 218242 (JP, A) JP-A-2-121495 (JP, A) JP-A-1-36541 (JP, A) JP-B-54-21915 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60R 16/02

Claims (4)

(57) [Claims] 1. A vehicle multiplex transmission device for transmitting state signals collected by one sensor communication node to a plurality of other communication nodes for the purpose of vehicle control, comprising: a serial bus line provided for communication; A parallel bus line provided for data transfer, a RAM node connected to the parallel bus line, and a communication node connected to the serial bus line without being connected to the parallel bus line, A first sensor communication node that detects a predetermined state and sends the state to the serial bus line as a first state signal, and a communication node connected to both the serial bus line and the parallel bus line, The first state signal from the first sensor communication node is received on the serial bus line to control the vehicle. And it converts the second state signal by processing the state signals,
A second communication node for writing the second state signal to the RAM node via the parallel bus line, and a communication node connected to at least the parallel bus line for controlling the vehicle; And a third communication node for reading out the second state signal from the RAM node via the parallel bus line. 2. The multiplex transmission device for a vehicle according to claim 1, wherein said third communication node is further connected to said serial bus line. 3. The second communication node and the third communication node have an interrupt control function, and the second communication node transmits the second state signal to the RAM via the parallel bus line. When writing to a node, the third communication node interrupts the third communication node, and the third communication node transmits the second state signal from the RAM node when interrupted by the second communication node. 2. The multiplex transmission device for a vehicle according to claim 1, wherein the transmission is performed. 4. The RAM node includes a storage area for storing a status signal, and a storage area for storing a flag indicating that the status signal is stored, wherein the third communication node has a predetermined area. 2. The multiplex transmission device for a vehicle according to claim 1, wherein the flag area is checked at a timing to check whether or not there is a newly stored state signal.