JPS63237628A - System for codeing vehicle multiplex transmission system - Google Patents

Abstract

PURPOSE:To attain the high reliability of multiplex transmission of data while maintaing high transmission efficiency by varying the redundancy depending on the importance of vehicle driving information to code the information. CONSTITUTION:Data are coded by varying the redundancy depending on the importance of vehicle driving information in a manner that as the importance of a vehicle driving information goes to high level, for instance, the more number of bits are allocated then the information is coded, or that the information are classified in accordance with the degrees of importance, thereafter error detection codes having bit lengths corresponding to the importance are added and codes in the case of coding vehicle driving information. Therefore, without increasing the number of the check bits of the whole frames, the check function for the vehicle driving information having high importance can be strengthen. As a result, while keeping high transmission efficiency, the high reliability of signal transmission can be guaranteed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a vehicle multiplex transmission system in which vehicle driving information multiplexed within one frame is classified into multiple degrees of importance. Concerning how to encode.

(Prior Art) Conventionally, it has been put into practical use that a microcomputer is installed in a car to control various parts of the car. In such control, various vehicle driving information inputs are encoded, converted into serial data, and multiplexed transmitted frame by frame over the data bus.

By the way, as an encoding method in such a vehicle multiplex transmission system, the document Autonot:ve Eng
i-neering, August, 1980, Vo
rM as described in I, 8g, No. 8, pp50-56
ultiplexing simplifications an
d expandsdriver controls
However, in the encoding method in the conventional vehicle multiplex transmission system described in this document, one bit of information is assigned to any vehicle driving information input.

In other words, information multiplexed within one frame includes start information (START), as shown in FIG.
), priority information, destination address information, source address information 1 Vehicle driving information (ignition switch on/off information (iGN-SW), start switch on/off information (start SW), headlamp on/off information (headlamp), small Lamp on/off information (small lamp), fog lamp on/off information (
fog lights), washer motor on/off information (washer motor).

Turn light switch signal on/off information (turn R),
Turn left switch signal on/off information (turn)
, error detection information (8-bit CRC).

There is data end information Ig (ENI) OF DATA), but in particular vehicle driving information (data) is divided into one for each of the five switch signals, as is clear from this Figure 4.
Bits are assigned bit by bit.

Note that for each data, "1" means on, and "0" means off.

(Problems to be Solved by the Invention) However, in the encoding method in such a conventional vehicle multiplex transmission system, one switch signal corresponds to one bit, so it may have an important effect on the running of the vehicle, for example. The on/off signal of the ignition switch, which gives the same information, and the on/off signal of the fog lamp, which has relatively low importance, are treated with the same importance, and as a result, the probability of malfunction of vehicle driving information becomes the same for all of them.

Therefore, if the important ignition (frame check function according to the word name) is strengthened by providing 16 bits and 7 bits as shown in Figure 5, the check bits will have to be increased for all frames, and this will result in There is a problem that the transmission efficiency decreases.

The present invention aims to solve these problems, and provides an encoding method for a vehicle multiplex transmission system, which enables data multiplex transmission with high reliability while maintaining high transmission efficiency. With the goal.

(Means for Solving the Problems) In order to achieve the above-mentioned object, according to the present invention, there is provided a multiplex transmission system for a vehicle in which vehicle driving information multiplexed and transmitted within one frame is classified into a plurality of degrees of importance. In the present invention, there is provided an encoding method for a multiplex transmission system for a vehicle, characterized in that when encoding the vehicle driving information, the redundancy is changed depending on the degree of importance of the vehicle driving information.

(Function) In the encoding method in the vehicle multiplex transmission system of the present invention described above, when encoding the vehicle driving information, for example, the higher the importance of the vehicle driving information, the more allocated bits are encoded. By classifying vehicle driving information into classes based on the same level of importance and then adding and encoding error detection codes with bit lengths corresponding to the level of importance, redundancy is created according to the level of importance of vehicle driving information. Encoding is performed at different degrees.

(Embodiment) Hereinafter, a coding method in a vehicle multiplex transmission system as an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is an overall configuration diagram showing an example of a vehicle multiplex transmission system to which the method of the present invention is applied. In this multiplex transmission system for a vehicle, a headlamp switch 16. Small lamp switch 17 for turning on and off the small lamp 9. Turn light switch 18. Turns on/off the right turn signal lamp lO. Turn left switch 19 for turning on and off the left blinker lamp 11. Fog lamp switch 20 that turns the fog lamp 12 on and off. Washer morus inch 21 for turning on and off the washer motor 13.
Starter motor! A start switch 221 turns on and off the main relay 15 for the power line to the ignition system and fuel system. The on/off information is input to the input interface 28 of the switch multiplex terminal station 4 on the transmitting side, and is further input to the communication control circuit IA.
The data is then transmitted frame by frame as serial data through the multiplex signal transmission line 6, and then converted to parallel data at the output interface 3 via the communication control circuit IB of the front multiplex terminal 5 on the receiving side. Furthermore, a spin lamp element (transistor, etc.) for operating each switch? The headlamps 8.A to 7H are turned on and off as appropriate according to the on/off information from the switches 16 to 23 described above. Small lamp9. Right blinker lamp 10
．． Left turn signal lamp 11. Fog lamp I2. Washer motor 13. Starter motor 14. main relay 1
5 is turned on or activated as appropriate.

By the way, in this embodiment, the vehicle driving information (data) includes ignition on/off information (IGN-SW), start switch on/off information (start SW), as in the conventional one (see Figure 4.5). ), headlamp on/off information (headlamp), small lamp on/off information (small lamp), fog lamp on/off information (fog lamp), washer motor on/off information (
washer motor), turn light switch signal on/off information (turn R), and turn left switch signal on/off information (turn OFF), these pieces of information differ in their importance for vehicle operation.

Therefore, these pieces of information are divided into three ranks in descending order of my degree, and the one with the highest degree of importance is given the degree of importance I, and as the degree of importance decreases, the degree of importance is given to ■.

Let the importance level be m. Here, information that falls under importance level 1 can include ignition on/off information and start switch on/off information, and information that belongs to importance level H can include headlamp on/off information and small lamp on/off information. Information belonging to the importance level ■ includes fog lamp on/off information, washer motor on/off information, turn light switch on/off information, and turn left switch on/off information I.

When encoding this information, the degree of redundancy is changed depending on its importance. That is, as shown in Fig. 1, during encoding, one bit is assigned to each switch signal for the switch signal with the lowest importance level ■, and one bit is assigned to the switch signal with the lowest importance level ■. One sui.

Two bits are assigned to each child signal, and three pins are assigned to one switch signal for a switch signal with an importance level of 1, which is the most important.

Here, for information assigned 1 bit, "1" means on and "0" means off, and for information assigned 2 bits, "11" means on and "00" means off. And with the information assigned 3 bits, rlooJ
is on, r 001. J means off.

Note that other inertia within one frame is determined by [start information (
START), priority information 1, destination address information, source address information, error detection information (8-bit 2-bit CRC), data end information (END OF DAT)
For ^)), the same number of bits as the conventional one shown in FIG. 4 is allocated.

In this way, the degree of redundancy during encoding is changed depending on the level of importance of vehicle driving information, so one switch signal is
The probability of malfunction due to noise is greatly reduced compared to when allocating to bits. In addition, as shown in Figure 5, compared to other conventional methods that improve the checking ability by simply increasing the number of error nick bits, it does not increase overhead and is more efficient in transmission even when there are many signals of low importance. There is no disadvantage in this respect.

In the example shown in Figure 1, the 8-node CRC is used for error checking of the entire frame, but this can be replaced by other error checking methods such as the inverted double transmission method, horizontal and vertical parity check methods, etc. It can also be realized in the same way.

Furthermore, in the example shown in FIG. 1 mentioned above, it can be said that the check mark is added to each highly important signal within one frame, but the highly important signals are shown in FIG. 3. It is also possible to collect them into classes (clusterize) for each level of importance, and add a check code with a bit length according to the degree of importance. , start switch on/off information i1), 2-bit CI? C (parity) is given, and CRC (parity) of 1 pit is given to the two switch signals of importance level ■ information (headlamp on/off information, small lamp on/off information), and importance degree of importance level ■ is given. Redundancy is not given to one switch signal (fog lamp on/off information, washer motor on/off information, turn light switch on/off information, turn left switch on/off information), and an 8-bit CRC is given as a whole.

In the example shown in Fig. 3, 2-bit CRC and 1-bit CRC are used for groups of importance levels ■ and ■, respectively, and 8-bit CRC is used for the entire frame.
However, for groups with importance level I, inversion 2 is adopted.
It goes without saying that it is also possible to use a continuous transmission method, and a configuration in which the inverted two-continuous transmission method is used for the entire frame, and furthermore, it can be similarly realized by a combination of the inversion two-continuous transmission method with CRC.

(Effects of the Invention) As detailed above, according to the encoding method in the vehicle multiplex transmission system of the present invention, encoding is performed with the degree of redundancy changed depending on the importance of vehicle driving information. , it is possible to strengthen the checking function of highly important vehicle driving information without increasing the number of check bits in all frames, and has the advantage of guaranteeing highly reliable signal transmission while maintaining high transmission efficiency. be.

[Brief explanation of drawings]

Figures 1 and 2 show a coding method in a vehicle multiplex transmission system as an embodiment of the present invention. Figure 1 is a schematic diagram showing the multiplex transmission data arrangement, and Figure 2 shows the method of the present invention. An overall configuration diagram showing an example of an applied vehicle multiplex transmission system, and FIG. 3 is a schematic diagram showing a multiplex transmission data arrangement for explaining the encoding method in a vehicle multiplex transmission system as another embodiment of the present invention. 4.5 are schematic diagrams showing multiplex transmission data arrays for explaining the encoding method in the conventional vehicle multiplex transmission system. IA, IB...Communication control circuit, 2...Input interface, 3...Output interface, 4...Switch multiple terminal station, 5...Front multiple terminal station, 6...
Multiple signal transmission line, 78-7H... switching element,
8...Headlamp, 9...Small lamp, IO
... Right turn signal lamp, 11 ... Left turn signal lamp, 12 ... Fog light, 13 ... Washer motor, 14 ... Starter motor, 15 ... Main relay, 16 ... Headlamp switch , 17...
Small lamp switch, 18... Turn light switch, 19... Turn left switch, 20... Fog lamp switch, 21... Wofsha motor inch, 22... Start switch, z3... Ignition switch.

Claims (3)

[Claims] (1) In a vehicle multiplex transmission system in which vehicle driving information that is multiplexed and transmitted within one frame is classified into multiple degrees of importance, when encoding the vehicle driving information, it is necessary to An encoding method in a vehicle multiplex transmission system characterized by encoding with varying degrees of redundancy. (2) An encoding method in a vehicle multiplex transmission system according to claim 1, characterized in that the higher the importance of the vehicle driving information, the greater the number of allocated bits for encoding. (3) The vehicle driving information is divided into classes according to the same degree of importance, and then an error detection code having a bit length corresponding to the degree of importance is added and encoded. An encoding method in a vehicle multiplex transmission system according to item 1.