JPH11115647A - Vehicular multiplex communication circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a wrong assembly by setting peculiar ID codes on a plurality of sub-controllers respectively, reading the ID codes of respective sub- controllers at the throwing in time of an electric source, comparing with a regular ID code memorized on a main controller and shifting the main controller to an usual action mode at the matched time. SOLUTION: A tuning constant and ID code peculiar to respective protection devices 2, 3 are set and memorized to ROM 37, 43 of the occupant SIDE IM PACT protection device 2 for a front passenger seat and the occupant side impact protection device 3 for a driver's seat. The regular ID codes of each of occupant crash protection devices 2, 3 are set and memorized to the first ROM 17 of an occupant front impact protection device 1. At the throwing in time of an electric source, the regular ID code is read from the first ROM 17 in the microcomputer 15 of the occupant front impact protection device 1 and also the ID codes set and memorized on the second/third ROM 37, 43 are read and they are compared with each other and at the matched time, they are shifted to an usual action made, while at the unmatched time, a wrong detection warning is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplex communication circuit for a vehicle used for an occupant protection device including a plurality of airbags for protecting an occupant in the event of a vehicle collision.

[0002]

2. Description of the Related Art FIG. 2 shows an occupant protection apparatus using a vehicle multiplex communication circuit of this type, and the structure thereof will be described below with reference to FIG. That is, what is shown in FIG.
The front occupant protection device 1, the front passenger occupant protection device 2 and the driver occupant side collision occupant protection device 3 are combined using multiplex communication. Next, the passenger side side occupant protection device 2 will be described. Note that the driver's side passenger occupant protection device 3 is substantially the same as the passenger seat side occupant protection device 2, and a detailed description thereof will be omitted.

First, the configuration of the front collision occupant protection device 1 will be described. That is, 4 is a battery, 5 is an ignition switch, and 6 is a booster circuit, which boosts an input voltage from the battery 4 supplied through the ignition switch 5 and charges a backup capacitor 8 through a resistor 7. The boosted voltage is supplied to the passenger side side occupant protection device 2 via the first switch circuit 10 and the resistor 11 inserted in the power supply line 9 in series.
The boosted voltage is supplied to the driver's side side occupant protection device 3 through the second switch circuit 13 and the resistor 14 inserted in series. Reference numeral 16 denotes a longitudinal acceleration sensor that detects acceleration generated in the longitudinal direction of the vehicle. An acceleration signal, which is a detection signal, is supplied to the microcomputer 15.

The microcomputer 15 has a collision judgment function, and when the collision judgment function is executed, the first RO
An algorithm tuning constant for collision determination stored in M (abbreviation of read only memory) 17 is read, and a collision is determined by executing an algorithm tuned based on the constant. That is, the microcomputer 15 is shared in terms of hardware for all types of vehicles, and differs only in tuning constants related to the operation of the algorithm. For this reason, it is possible to judge a collision occurring in all the vehicle types by writing a tuning constant suitable for the vehicle type in the first ROM 17.
The microcomputer reads a tuning constant from the reference 17, calculates an acceleration signal supplied from the longitudinal acceleration sensor 16 by a predetermined algorithm, and turns on the switch circuit 18 when it is determined that a serious collision has occurred.
Is discharged through the discharge diode 19, and an ignition current is supplied to the primer 20 and the mechanical acceleration switch 21 in series.

[0005] The microcomputer 15 comprises:
It has a failure diagnostic function for important circuit portions of the front collision occupant protection device 1, the passenger side side occupant protection device 2, and the driver side side occupant protection device 3, for example, a passenger side side occupant protection device. When the failure data is detected by performing multiplex communication with the second microcomputer 28 via the power supply line 9 or when the failure of the front occupant protection device 1 is detected, an alarm is issued via a not-shown alarm unit. Further, the microcomputer 15 is provided for a predetermined time immediately after the ignition switch 5 is turned on (this predetermined time is provided for the microcomputer 28 of the side collision occupant protection devices 2 and 3 to perform an initial failure diagnosis. The first and second switch circuits 10 and 13 are turned off via the signal lines X and U, and the third switch circuit 40 is turned on via the signal line T. Of the respective microcomputers 28 (the microcomputer of the driver's seat side occupant protection device 3 is not shown) is started.

[0006] The microcomputer 15 comprises:
A request signal is transmitted to the microcomputer 28 of the passenger side side occupant protection device 2 via the signal line S, the first communication circuit 26, the switching transistor 22, the resistor 23 and the power supply line 9, and The response signal from 28 is input via the second communication circuit 32, the switching transistor 36, the resistor 35, the power supply line 9, and the signal line V. The microcomputer 15 also provides a signal line S, a first communication circuit 26, and a switching transistor 2 to the microcomputer (not shown) of the driver's side side occupant protection device 3.
4, a request signal is transmitted through the resistor 25 and the power supply line 12, and a response signal from the microcomputer of the driver's side passenger occupant protection device 3 (not shown) is transmitted in the same manner as the passenger side passenger occupant protection device 2. , Via a communication circuit, a switching transistor, a resistor, a power supply line 12 and a signal line Y.

Reference numeral 18 denotes a switch circuit which is interposed between the booster circuit 6 and the squib 20 and is turned on when an ignition signal is supplied from the microcomputer 15 to comprise the squib 20 and the mechanical acceleration switch 21. Supply the ignition current to the series circuit. When this ignition current is supplied,
It goes without saying that the mechanical acceleration switch 21 is on. When a request signal is supplied from the microcomputer 15 via the signal line S, the first communication circuit 26 switches the two switching transistors 22 based on the address data attached to the request signal.
24, which is selectively turned on, and the request signal is transmitted via the power supply line 9 or 12 to either the passenger side passenger occupant protection device 2 or the driver seat side occupant protection device 3. To be transmitted.

Reference numerals 38, 41, and 42 denote backflow preventing diodes, 39 denotes a resistor, and a series circuit including a diode 38, a resistor 39, a third switch circuit 40, and a diode 41;
And the diode 28, the resistor 29, and the third switch circuit 4.
A series circuit composed of 0 and the diode 42 is configured to operate only for a predetermined time immediately after the ignition switch 5 is turned on.

Next, the passenger-side side occupant protection device 2 will be described. An acceleration sensor 27 is the same as the longitudinal acceleration sensor 16 and has a different detection direction from the longitudinal acceleration sensor 16 and is mounted so as to detect the lateral acceleration of the vehicle. 28. The microcomputer 28 has a collision judging function similarly to the microcomputer 15, and based on an acceleration signal supplied from the lateral acceleration sensor 27 and a switch signal supplied from an acceleration switch 29 described later, The magnitude of the collision from one side is determined, and when it is determined that the collision is a serious collision, the switch circuit 30 is turned on to supply an ignition current to the primer 31.

The microcomputer 28 has a diagnostic function similarly to the microcomputer 15, and
Diagnosis such as disconnection of the first communication circuit 26 is performed, and based on a request signal supplied through the first communication circuit 26, the diagnosis result is transmitted to the second communication circuit 32 (the same as the first communication circuit 26), It is supplied to the microcomputer 15 of the front occupant protection device 1 via the line 9 and the signal line V. The acceleration switch 29 includes a semiconductor acceleration sensor and a comparison circuit, and outputs a switch signal when an output from the semiconductor acceleration sensor exceeds a reference value of the comparison circuit.

Reference numeral 36 denotes a switching transistor composed of a field effect transistor, which is turned on and off by an output signal of the second communication circuit 32 and outputs a signal indicating a result of various diagnoses. 35 is a resistor inserted between the switching transistor 36 and the power supply line 9;
When the switching transistor 36 is turned on (or a switching transistor formed on the output side of the first communication circuit 26), the voltage on the anode side of the backflow prevention diode 33 is connected in series with the resistor 11 via the power supply line 9. When (not shown) is turned on), the input voltage is maintained at a constant voltage other than 0 level so that the input voltage can be constantly supplied to a constant voltage circuit 34 described later.

Reference numeral 37 denotes a second ROM having the same function as that of the first ROM 17, which stores a tuning constant of an algorithm for collision determination similarly to the first ROM 17, and which is used by the microcomputer 28 when making a collision determination. The tuning constants related to the calculation of are stored.

The power supply lines 9 and 12 are connected to each other when the front passenger occupant protection device 1 and the front passenger occupant protection device 2 are communicating with each other.
When communication is performed between the driver and the driver's seat side occupant protection device 3, the voltage waveform is as shown in FIG. That is,
In FIG. 3, the voltage V1 is, for example, a value obtained by dividing the output voltage V3 of the booster circuit 6 when the switching transistor 36 is turned on by the resistors 35 and 11, and the voltage V2 is the resistance 11 of the voltage when the switching transistor 36 is turned off. Is determined by the value of

Next, the operation of the above configuration will be described with reference to FIG. First, when the ignition switch 5 is turned on (step ST100), the microcomputer 1
Steps 5 and 28 enter a communication initial diagnosis mode in step ST110, in which it is determined whether the front collision occupant protection device 1 can communicate with the front passenger occupant protection device 2 and the driver side occupant protection device 3. It diagnoses whether the function is operable, the collision determination function is operable, and the like. After that, the microcomputer 15, 2
In step ST120, the process proceeds to step ST120, in which processing such as address assignment of an internal memory is performed.
In step ST130, the microcomputers 15, 2
In order to output a watchdog pulse to an external watchdog timer (not shown), the logic of the watchdog pulse output terminal is inverted every time this step is passed. Thereafter, the process proceeds to a normal failure diagnosis step ST140 and a collision determination step ST150 described below.

(1) Normal failure diagnosis function (step ST1)
40) When the microcomputer 15 of the front collision occupant protection device 1 starts operating, the microcomputer 15 connects the first and second switch circuits 10, 1 via the signal lines U, X.
3 and the third switch circuit 40 is switched to the on state, and the program of the microcomputer 15 of the front occupant protection device 1 and the program of the Microcomputer 28
And the program of the microcomputer of the driver's seat side occupant protection device 3 start operating simultaneously and individually.

After the predetermined time has elapsed, the microcomputer 15 of the front occupant protection device 1 sends the signal to the microcomputer of the front passenger occupant protection device 2 via the signal line S, the first communication circuit 26 and the like. A request signal is supplied, and a response signal to the request signal is transmitted from the microcomputers of the passenger and driver side passenger occupant protection devices 2 and 3 via a communication circuit and a switching transistor, etc., to the front occupant protection device 1. Microcomputer 1
A response signal including a diagnosis result is transmitted to the control signal No. 5.
As a result, if it is determined that an abnormality such as a failure has occurred even in a part of the entire circuit, an alarm signal is output from the microcomputer 15 of the front occupant protection device 1 to an alarm device (not shown). Is done.

For example, the microcomputer 28 in the passenger-side side occupant protection device 2 of the side-side occupant protection devices 2 and 3 that have received the request signal includes various components in the passenger-side side occupant protection device 2, For example, by reading the terminal voltage of the primer 31 and turning on and off the switching transistor 36 by the output of the second communication circuit 32, the signal line V is connected to the microcomputer 15 of the front collision occupant protection device 1 via the power supply line 9. The microcomputer 15 determines whether there is a signal indicating a failure or not, and activates the alarm device when it determines that there is a signal indicating a failure. It goes without saying that the same operation is performed for the driver's side side occupant protection device 3 as well.

(2) Collision judgment function (step ST15)
0) After the completion of the various diagnoses, each microcomputer is connected to the first, second and third connected to the respective microcomputer.
The tuning constants are read from the ROMs 17, 37, and 43, and an algorithm program for collision determination is set. Thereafter, when the vehicle has a frontal collision, the mechanical acceleration switch 21 of the frontal occupant protection device 1 is turned on, and the microcomputer 15 further activates the longitudinal acceleration sensor 1.
When it is determined that a serious collision has occurred based on the acceleration signal from 6,
The microcomputer 15 controls the switching circuit 18 to turn on the switch circuit 18 to supply the electric charge charged in the backup capacitor 8 to the primer 20 via the discharging diode 19, deploy the airbag and the like, and protect the occupant from a forward collision.

When the vehicle is collided in the lateral direction, ie, the driver's seat side door or the passenger's seat side, the mechanical acceleration switch 21 of the front collision occupant protection device 1 is not turned on, and the longitudinal acceleration sensor is not turned on. 16 does not output an acceleration signal having a magnitude corresponding to the acceleration signal associated with the forward collision, so that no ignition current is supplied to the primer 20.

However, the microcomputer 28 of one of the side collision occupant protection devices, for example, the passenger side collision occupant protection device 2 is an acceleration switch 29.
When it is determined that a serious collision has occurred based on the switch signal from the switch and the acceleration signal from the lateral acceleration sensor 27, the switch circuit 30 is turned on to control the backup capacitor 8
Is supplied to the primer 31 via the power supply line 9 to deploy the airbag to protect the occupant from a side collision. It goes without saying that the same operation is performed also for the driver's side side occupant protection device 3.

[0021]

However, when the occupant protection device shown in FIG. 2 is used, the hardware of the side collision occupant protection devices 2 and 3 is set to be shared between the vehicle types, and each of them is set. Since only the tuning constant of the collision algorithm of the microcomputer of the model is set to be different, for example, at the time of impact inspection after assembling the vehicle, it is necessary to install a proper side collision occupant protection device, other different If you notice that you have installed a side collision occupant protection device for your vehicle type, you will have to disassemble and re-attach it with a lot of man-hours. For this reason, a strict management system had to be established and stored and managed, which was very difficult.

In view of the above, the present invention has been made in view of the above-mentioned problem, and it has been made possible to check whether or not a proper assembling has been performed by performing only electric connection between occupant protection devices. Aim.

[0023]

A multiplex communication circuit for a vehicle according to the present invention includes a plurality of sub-control units and a main control unit connected to each of the sub-control units. In the vehicle multiplex communication circuit that performs multiplex communication with a sub-control unit, each of the plurality of sub-control units has an ID code uniquely set, and the main control unit includes the sub-control unit. Is stored in each of the sub-control units when the power is turned on, reads the ID code set in each of the sub-control units, compares with the normal ID code, and when there is a match, The main control unit executes a normal operation mode, and in the case of a mismatch,
It is characterized in that a notifying signal is generated for activating notifying means for notifying that any of the sub-control units is not a proper one.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. A first embodiment according to the present invention will be described. The configuration is almost the same as that shown in FIG.
The ROMs 37 and 43 of the passenger-side side occupant protection device 2 and the driver-side side occupant protection device 3 have, in addition to the tuning constants specific to each, an ID code and operation specific to the passenger-side side occupant protection device 2. ID unique to the seat side occupant protection device 3
The codes are set and stored as a set, and the first ROM 17 of the front occupant protection device 1 further sets and stores the regular ID codes of the passenger side side occupant protection device 2 and the driver side side occupant protection device 3. In addition, the ID code collation function is added to the function of the microcomputer 15 because the ID code is set and stored.
That is, as shown in FIG. 1, steps ST160, ST170, and ST180 are added to the flowchart, which will be described below. This corresponds to the vehicle type to which the front occupant protection device 1 is assembled.

That is, in FIG. 1, step ST1
60 is a microcomputer of the front occupant protection device 1
5 reads the regular ID code from the first ROM 17, and stores the ID code set and stored in the second and third ROMs 37, 43 into the microcomputers 28 (driver side seat occupant) of the side occupant protection devices 2, 3. The microcomputer of the protection device 3 is read via a not shown). In step ST170, when the ID codes of both side occupant protection devices 2 and 3 read in step ST160 are compared with the regular ID codes read from the first ROM 17, it is determined that they match, and in step ST12.
Go to 0. If it is determined in step ST170 that the ID codes do not match, the process proceeds to step ST18.
Proceed to 0, issue a false alarm and instruct reassembly.

This check is performed by electrically connecting the occupant protection devices 1, 2, and 3 to each other at the time of temporary connection before the vehicle assembly is completed.

[0027]

As described above, according to the present invention, it is possible to check whether or not a proper occupant protection device has been assembled before the vehicle assembly is completed. This has the effect of promoting the sharing of the same.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a microcomputer of a front collision occupant protection device when a vehicular multiplex communication device according to the present invention is used in an occupant protection device.

FIG. 2 is an explanatory diagram of a circuit block when a conventional vehicle multiplex communication device is used for an occupant protection device.

FIG. 3 is a waveform chart for explaining a communication method of the circuit block of FIG. 2;

4 is an explanatory diagram of a flowchart of a microcomputer of the conventional front occupant protection device of FIG. 2;

[Explanation of symbols]

 16, 27 Acceleration sensor 15, 28 Microcomputer 10, 13, 18, 30 Switch circuit 20, 31, Detonator 26, 32 Communication circuit 22, 24, 36 Switching transistor 29 Acceleration switch 17, 37, 43 ROM

Claims (1)

[Claims] 1. A vehicular multiplex comprising: a plurality of sub-control units; and a main control unit connected to each of the sub-control units, and performing multiplex communication between the main control unit and the plurality of sub-control units. In the communication circuit, each of the plurality of sub-control units has an ID code uniquely set, and the main control unit stores a regular ID code set in each of the sub-control units, When the power is turned on, the main control unit reads an ID code set in each of the sub-control units, compares the read ID code with the regular ID code, and when they match, executes the normal operation mode, If there is a mismatch,
A multiplex communication circuit for a vehicle, wherein the multiplex communication circuit generates a notification signal for activating notification means for notifying that any of the sub-control units is not a proper one.