JP3719371B2 - Vehicle occupant protection system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a vehicle occupant protection system.
[0002]
[Prior art]
  Conventionally, in a vehicle occupant protection system, there is an airbag system as disclosed in JP-A-10-154992. This airbag system is configured by connecting an electronic control device and a plurality of ignition circuits to the same serial communication bus.
[0003]
[Problems to be solved by the invention]
  By the way, according to the airbag system, the electronic control device controls each ignition circuit using software via the same serial communication bus based on the detection output of the acceleration sensor. Therefore, even if the number of ignition circuits increases in the future, the electronic control device only needs to be changed by software.
[0004]
  However, for example, when the acceleration sensor erroneously detects and outputs a collision of the vehicle, this erroneous detection output is given to each ignition circuit by the same serial communication bus. Therefore, the ignition circuit may cause the airbag to malfunction.
[0005]
  Further, in the airbag system, if the electronic control device has only one collision determination function part, the airbag is similarly detected even when the collision determination function part erroneously determines the collision of the vehicle. May malfunction.
[0006]
  Therefore, in order to deal with the above, the present invention prevents malfunction of the occupant protection mechanism if there is only one failure regardless of the occurrence of any failure in the vehicle occupant protection system. For the purpose.
[0007]
[Means for Solving the Problems]
  In solving the above-described problems, a vehicle occupant protection system according to the invention described in claim 1 includes a plurality of occupant protection mechanisms, a plurality of acceleration sensor modules (20 to 20c), and a plurality of devices mounted at different positions of the vehicle. The squib module (30 to 30 g) and the electronic control device (10), and the serial communication bus (40) formed by connecting each acceleration sensor module, each squib module, and the electronic control device.
[0008]
  In the vehicle occupant protection system, each of the plurality of acceleration sensor modules includes an acceleration sensor (21) that detects the acceleration of the vehicle at different positions of the vehicle, and the acceleration detected by the acceleration sensor is used for the corresponding squib module. And transmission means (23, 218) for transmitting the data as acceleration data to the serial communication bus.
[0009]
  Further, the electronic control unit determines the presence or absence of a vehicle collision based on the acceleration data for the corresponding squib module on the serial communication bus, and transmits the determination result to the serial communication bus as the corresponding squib module determination data. Means (15, 16, 116) are provided.
[0010]
  In addition, each of the plurality of squib modules is a squib (39a) that is driven when operating a corresponding occupant protection mechanism among the plurality of occupant protection mechanisms, and only when both are connected in series to the squib and are turned on. Both ignition switches (38, 39) for driving the squib and collision determination means (37) for determining the presence or absence of a vehicle collision based on the acceleration data for the corresponding squib module on the serial communication bus and turning on one of the ignition switches ). The other ignition switch of both ignition switches is turned on when the corresponding squib module determination data on the serial communication bus indicates a vehicle collision.
[0011]
  Thus, for each squib module, the squib is driven only when both of the ignition switches are turned on. Therefore, the squib is not driven when only one of the two ignition switches is turned on. In other words, even if only one of the two ignition switches is erroneously turned on due to a failure of the system, the squib is not driven, so that the malfunction of the occupant protection mechanism can be reliably prevented.
[0012]
  MaClaim2In the invention described in claim1In the vehicle occupant protection system according to claim 1, the collision determination unit of the electronic control device transmits the determination data for the corresponding squib module to the serial communication bus in a signal form different from the acceleration data for the corresponding squib module. And Thereby, the collision determination means of each squib module can correctly determine the corresponding squib module determination data without mistaken the corresponding squib module acceleration data. As a result, the claims1The effect of the invention described in 1 can be achieved with higher accuracy.
[0013]
  Claims3According to the invention described in claim2In the vehicle occupant protection system described above, the signal form of the determination data for the corresponding squib module has a voltage amplitude different from that of the acceleration data for the corresponding squib module. As a result, the claim2The effects of the invention described in 1) can be further improved.
[0014]
  Claims4In the invention described in claim 1, the claims 1 to3In the invention described in any one of the above, the collision determination means of the electronic control device determines including the collision mode of the vehicle. As a result, the determination by the collision determination means of the electronic control device is performed in consideration of the collision mode.1Thru3As a matter of course, the occupant protection mechanism can be operated in accordance with the collision site and acceleration state of the vehicle.
[0015]
  Moreover, in invention of Claim 5, in invention of any one of Claims 1 thru | or 4,The electronic control device includes ignition command transmission means (128) for transmitting a corresponding squib module ignition command for any of the plurality of squib modules to the serial communication bus, and each of the plurality of squib modules includes a serial communication bus. The ignition command for the corresponding squib module above is received, the presence or absence of a vehicle collision is determined based on the determination data for the corresponding squib module on the serial communication bus, and the other ignition switch is turned on when it is determined that there is a collision. Other collision determination means (321 to 324) are provided.
[0016]
  In this way, the other collision determination means of the squib module determines the presence or absence of a collision based on the ignition command of the electronic control unit. Therefore, while further increasing the number of collision determinations, the invention according to claim 1 Similar effects can be achieved.
[0017]
  In the invention according to claim 6,5In the invention described in the item 1, one of the both collision determination means of the plurality of squib modules is determined including the collision form of the vehicle. Thereby, one of the collision determination means of each squib module is determined in consideration of the collision mode.5The occupant protection mechanism can be operated in a state that matches the collision site and the acceleration state of the vehicle.
[0018]
  In the invention according to claim 7, the claim5In the vehicle occupant protection system described in (1), the electronic control device immediately after the start of the operation, information for determining one of the both collision determination means of the plurality of squib modules including the collision mode of the vehicle, An information transmission means (104) for transmitting to the serial communication bus is provided, and one of the both collision determination means of the plurality of squib modules is determined based on the information on the serial communication bus, including the vehicle collision mode. It is characterized by that.
[0019]
  According to this, since the same effect as the invention of Claim 6 can be achieved, the information is transmitted on the serial communication bus by the information transmission means of the electronic control unit. Even if the number of squib modules or acceleration sensor modules is changed, it is only necessary to change information in the information transmission means of the electronic control device, and an easy and flexible response to the change of the system is possible.
[0020]
  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of an airbag system for a passenger car according to the present invention. This airbag system includes an electronic control unit 10 (hereinafter referred to as ECU 10), N acceleration sensor modules (hereinafter referred to as G sensor modules), M skib modules, ECU 10, each G sensor module, and each And a serial communication bus 40 connected between the squib modules.
[0022]
  In this embodiment, N = 4, and G sensor modules 20 to 20c are employed as four G sensor modules. Further, at M = 8, the squib modules 30 to 30g are employed as eight squib modules. N = 1 to N = 4 correspond to the G sensor module 20 to the G sensor module 20c, respectively. M = 1 to M = 8 correspond to the squib module 30 to squib module 30g, respectively. Further, each of the squib modules 30 to 30g is for actuating each airbag mechanism at each arrangement position of the vehicle described later. Each airbag mechanism deploys the airbag by its operation.
[0023]
  The serial communication bus 40 includes a ground line 41 and a power signal line 42. The ground line 41 grounds the ground terminals of the constituent elements of the ECU 10, the G sensor modules 20 to 20c, and the squib modules 30 to 30g.
The power signal line 42 supplies power to the G sensor modules 20 to 20c and the squib modules 30 to 30g from a power source (not shown) in the ECU 10.
The power supply signal line 42 is normally at the voltage a (V), and changes the voltage according to the digital signal during communication (see FIG. 4). The voltage width differs depending on the type of information, the diagnosis signal or the like is in the voltage range A (ab) (V), the acceleration data or the like is in the voltage range B (ac) (V), The ignition command or the like is in the voltage range C (ad) (V).
[0024]
  ECU10 is provided in the floor center left-right center part under the vehicle interior front wall of the said passenger car (refer FIG. 1). As shown in FIG. 3, the ECU 10 includes driver receivers 11 to 13, a data conversion circuit 14, a communication control circuit 15, and a collision determination circuit 16.
[0025]
  Each of the driver receivers 11 to 13 is connected between the power signal line 42 and the data conversion circuit 14 and functions as an interface circuit. Further, each of the driver receivers 11 to 13 performs power feeding between a power source (not shown) and each component in the ECU 10 and the G sensor modules 20 to 20 c via the power signal line 42.
[0026]
  The driver receiver 11 transmits and receives a signal in the voltage range A shown in FIG. 4 (such as a diagnostic signal) between the data conversion circuit 14 and the power supply signal line 42. The driver receiver 12 transmits and receives a signal (acceleration data or the like) in the voltage range B shown in FIG. 4 between the data conversion circuit 14 and the power supply signal line 42. The driver receiver 13 transmits and receives a signal (ignition command or the like) in the voltage range C shown in FIG. 4 between the data conversion circuit 14 and the power supply signal line 42.
[0027]
  The data conversion circuit 14 is connected between the communication control circuit 15 and each of the driver receivers 11 to 13, and this data conversion circuit 14 determines the sign of the output data from each of the driver receivers 11 to 13 for reception. The data is appropriately converted and output to the communication control circuit 15, and the bit error of the output data is also checked. The data conversion circuit 14 generates a message with a check bit added based on the output address and command from the communication control circuit 15 and outputs the message to one of the driver receivers 11 to 13 for transmission.
[0028]
  The communication control circuit 15 is connected between the data conversion circuit 14 and the collision determination circuit 16, and this communication control circuit 15 is connected to each G sensor module 20 to 20c connected to the power signal line 42. A request for acceleration data, a request for self-diagnosis, and an ignition command are transmitted to the power supply signal line 42 via the data conversion circuit 14 and the driver receivers 11 to 13. If there is a response to each request through the power signal line 42, the communication control circuit 15 receives the response through each of the driver receivers 11 to 13 and the data conversion circuit 14, and communicates with the entire airbag system. To control.
[0029]
  Further, the communication control circuit 15 outputs the acceleration data input via the data conversion circuit 14 to the collision determination circuit 16, receives data on the collision of the passenger car and information on the collision form from the collision determination circuit 16, An ignition command is generated and output to the data conversion circuit 14. The communication control circuit 15 has a microcomputer as a main element. With this microcomputer, a program is executed in accordance with the flowcharts shown in FIGS. 12 to 15, and the above-described processing in the communication control circuit 15 is performed. In addition, the memory of the microcomputer stores in advance each physical address, logical address, development attribute, and state information for specifying each G sensor module 20 to 20c and each squib module 30 to 30g (see FIG. 5 and FIG. 5). (See FIG. 10).
[0030]
  The collision determination circuit 16 is composed of a microcomputer. The collision determination circuit 16 is an acceleration transmitted from at least two of the G sensor modules 20 to 20c via the power signal line 42, the driver receiver 12, and the communication control circuit 15. The digital data is taken in, and based on the data, the presence / absence of a collision of the passenger car is determined. At the time of the determination as a collision, the type of collision is determined based on the data of FIGS. The determination data is sent to the power supply signal line 42 through the communication control circuit 15, the data conversion circuit 14 and the driver receiver 13. In the present embodiment, each development attribute in FIG. 5 and each data in FIG. 10 are set in consideration of acceleration characteristics according to the arrangement position of each squib module with respect to the passenger car.
[0031]
  As shown in FIG. 1, both G sensor modules 20 and 20a are mounted on the front left and right in the front bonnet of the passenger car. Both G sensor modules 20b and 20c are mounted on the left and right sides of the passenger compartment floor of the passenger car.
[0032]
  As shown in FIG. 6, each of the G sensor modules 20 to 20 c includes an acceleration sensor 21 (hereinafter referred to as a G sensor 21), an AD converter 22, a communication control circuit 23, a data conversion circuit 24, and the like. The G sensor modules 20 to 20c each convert the detected acceleration of the G sensor 21 by the A / D converter 22 according to the request of the ECU 10, A message is transmitted to the power supply signal line 42 through any one of the communication control circuit 23, the data conversion circuit 24, and both the driver receivers 25 and 26. However, if all the G sensor modules 20 to 20c transmit at the same time, the transmission signals collide on the power supply signal line 42, so that each G sensor module 20 to 20c performs transmission at different timings.
[0033]
  Here, the G sensor 21 of each G sensor module 20 to 20c detects the acceleration generated at the position where each G sensor module 20 to 20c is disposed with respect to the passenger car. The AD converter 22 digitally converts the acceleration detected by the G sensor 21 and outputs the digital acceleration to the communication control circuit 23 as acceleration digital data. The communication control circuit 23 operates in response to a request from the ECU 10. The communication control circuit 23 basically sends acceleration digital data and performs self-diagnosis and sends the result. Do.
[0034]
  The communication control circuit 23 includes a microcomputer as a main component, and the microcomputer controls the timing of each transmission in the communication control circuit 23 and each transmission according to the flowcharts shown in FIGS. This is done by executing the program. Each physical address shown in FIG. 7 is stored in advance in the memory area of the microcomputer memory (see FIG. 7). The memory is provided with another memory area for storing a logical address used only in the G sensor module having the memory.
[0035]
  The data conversion circuit 24 performs substantially the same processing as the data conversion circuit 14 of FIG. Both driver receivers 25 and 26 perform substantially the same processing as the driver receiver of FIG. Since the ignition command is not transmitted / received, a driver receiver corresponding to the driver receiver 13 is not necessary.
[0036]
  As shown in FIG. 8, the squib modules 30 to 30g include driver receivers 31 to 33, both data conversion circuits 34 and 35, a communication control circuit 36, an acceleration level determination circuit 37, and a normally open ignition. Switches 38 and 39 and a squib 39a are provided. The driver receivers 31 to 33 are the same as the driver receivers 11 to 13 in FIG.
[0037]
  Both data conversion circuits 34 and 35 are the same as the data conversion circuit 14 of FIG. 3, but the data conversion circuit 34 is connected between the communication control circuit 36 and each of the driver receivers 31, 32, and 33 to perform data conversion. The circuit 35 is connected between the acceleration level determination circuit 37 and the driver receiver 33.
[0038]
  The communication control circuit 36 has a function of turning on the ignition switch 38 in response to an ignition command from the ECU 10 via the driver receiver 32 and the data conversion circuit 34, and a function of performing self-diagnosis in accordance with a self-diagnosis command and sending out the diagnosis result. Have The communication control circuit 36 includes a microcomputer as its main component, and the microcomputer executes a program in accordance with the flowcharts shown in FIGS. Control and transmission.
[0039]
  Further, in the memory area of the microcomputer memory of the communication control circuit 36, physical addresses as shown in FIG. 9 are stored in advance. Furthermore, another memory area for storing a logical address used only in the squib module and an airbag deployment attribute (see FIG. 10) is secured in the memory. In FIG. 10, “0” represents the non-deployment of the airbag, and “1” represents the deployment of the airbag.
[0040]
  The acceleration level determination circuit 37 receives only the acceleration digital data from the data conversion circuit 35, and turns on the ignition switch 39 when the value of this data exceeds a predetermined acceleration level.
[0041]
  In the communication control circuit 36 configured as described above, both the ignition switches 38 and 39 are turned on to drive the squib 39a. Further, the ignition switch 38 is turned on in response to an ignition command from the ECU 10, and the ignition switch 39 exceeds the predetermined acceleration level when the acceleration digital data flowing in the power signal line 42 is read by the acceleration level determination circuit 37. Turn on when. As described above, since the squib 39a is driven by two independent systems, even if one of the systems breaks down and the ignition switch is turned on, the squib 39a is not ignited by the drive.
[0042]
  The squib module 30 operates the passenger seat airbag mechanism of the passenger car, and the squib module 30a operates the driver seat airbag mechanism of the passenger car. The squib modules 30b and 30d are provided on the left side of the passenger car. Each of the squib modules 30c and 30e operates a front and rear seat airbag mechanism on the right side of the passenger car, and the squib module 30f includes a left curtain airbag mechanism of the passenger car. And the squib module 30g operates the right curtain airbag mechanism of the passenger car.
[0043]
  Next, the communication rule in this embodiment is demonstrated. This communication rule is a master / slave method. The airbag system has one master and a plurality of slaves, and the slaves do not operate unless requested by the master. Therefore, the slaves do not communicate with each other without permission, but each slave monitors all the signals on the power supply signal line 42 even if there is no request from the master. A request from the master can specify a specific slave, and can send a request without specifying a slave. In the airbag system, the master is the ECU 10, and the slaves are the G sensor modules 20 to 20c and the squib modules 30 to 30g.
[0044]
  In the airbag system, the master uses three types of addresses, that is, a physical address, a logical address, and a deployment attribute in order to identify each slave. The physical address is an address assigned when each slave such as each G sensor module 20 to 20c or each squib module 30 to 30g is manufactured at a parts factory, and is used to set a logical address when the airbag system is started up. Used for. Each physical address is different from one another for each slave. Each physical address is preferably standardized according to the type of module and the mounting position.
[0045]
  The logical address is an address used to identify the slave during the normal mode of the airbag system. In general, the amount of information is smaller than the physical address because it is only necessary to be able to be identified within the airbag system. The purpose of not using a physical address in the normal mode is to improve communication efficiency.
[0046]
  The deployment attribute is set for each air bag deployable squib module, and this deployment attribute is information that specifies what type of collision of the passenger car should be deployed. Accordingly, an object is to ignite a plurality of squibs by a single ignition command (see FIG. 10). Each of the collision modes 1 to P includes the magnitude of acceleration, the transmission speed, and the airbag (the airbag of each airbag mechanism corresponding to each squib module) according to the collision site (arrangement position of each squib module) of the passenger car. ) Is specified.
[0047]
  In the communication control circuit 15 of the ECU 10 as the master, development attributes (see FIG. 10) representing the relationship between the individual squib modules and the collision modes 1 to P are stored in advance as format data. The master then transfers the information to the slave during initial operation. Along with this, the slave that is the squib module stores the information, checks this stored information with the collision mode information sent together with the ignition command from the master, and determines whether to drive the squib. decide. In order to avoid a match with the physical address, for example, the first bit of the physical address is set to 1, and the first bit of the expansion attribute is set to 0.
[0048]
  Next, the message format in this embodiment will be described. Basically, a message sent out in one transmission consists of an address, a data area, and a check bit, but the detailed parts are slightly different between master-to-slave communication and slave-to-master communication (Fig. 11).
[0049]
  The message from the master to the slave as shown in FIG. 11 includes a destination address, a data area, and a check bit. The destination address is a logical address to which the message is sent. It is also possible to designate all slaves by broadcast communication. The data area starts with a command and is followed by data. The check bit is a redundant bit for detecting a bit error on the power supply signal line 42 and preventing the malfunction. The message from the slave to the master is composed of a source address, data and check bits. The data varies depending on requests from the master, such as acceleration digital data and self-diagnosis results.
[0050]
  The operation of the present embodiment configured as described above will be described separately for the initial mode, the normal mode, and the ignition mode.
[0051]
  (1) Initial mode
  Based on FIGS. 12, 13, 16, 19, 20, and 23, an initial mode as an initial operation of the ECU 10, the G sensor modules 20 to 20c, and the squib modules 30 to 30g will be described.
[0052]
  First, the communication control circuit 15 of the ECU 10 serving as the master initializes n = 1 in step 100 of FIG. 12, and supplies the message n1 (see FIG. 23) through the data conversion circuit 14 and the driver receiver 11 in step 101. Send to signal line 42. As shown in FIG. 24, the message n1 includes a logical address, a physical address, and a check bit added by a data conversion circuit.
[0053]
  The communication control circuit 23 of each G sensor module that is each slave determines YES in step 200 of FIG. 16 based on the transmission message n1 and receives the message by using the microcomputer. The physical address contained in the password is checked against its own physical address. If they match, the microcomputer of the communication control circuit 23 writes the logical address of the message in the memory area at step 202, and informs the master at step 203 that the logical address setting has been performed normally. n1 ′ (see FIGS. 23 and 24) is transmitted to the power supply signal line 42 through the data conversion circuit 24 and the driver receiver 25. Ignore if they do not match.
[0054]
  Based on the transmission message n1 ′, the microcomputer of the master communication control circuit 15 receives the message n1 ′ based on the determination of YES in step 102 and confirms that the address setting has been normally performed. Later, if the slave is a deployable slave (squib module), it is determined YES in step 103, and a message n2 (see FIGS. 23 and 24) is sent to step 104 in order to set a deployment attribute. And transmit to the power signal line 42 in the same manner as described above. The message n1 and the message n2 are for logical address setting and development attribute setting, respectively.
[0055]
  The communication control circuit 36 of each squib module as a slave, in the same way as the processing in steps 200 to 203, after the processing in both steps 300 to 305 in FIG. 19, in step 306, the expansion attribute included in the message n2 Is stored in the memory, and the message n2 ′ (= message n1 ′) is transmitted to the power supply signal line 42 in the same manner as described above in step 307. The message n2 is also received by other slaves, but is ignored because the expansion attribute does not match any physical address.
[0056]
  Next, the microcomputer of the communication control circuit 15 of the ECU 10 determines YES in step 105 of FIG. 12 under reception of the message message n2 ′, and updates n = n + 1 = 2 in step 107. Thereafter, the above initial procedure is repeated for the remaining slaves until n> N + M.
[0057]
  If it is determined for all slaves and YES is determined in step 108, it is determined in step 109 whether there is a slave whose status information is 1. This determination is made based on the fact that the state information is set to 1 in step 106 when the determination in step 105 is NO. If YES in step 109, a warning is given in step 110 that there is an abnormality in the system configuration of the airbag system. Thus, the initial mode ends.
[0058]
  (2) Normal mode
  Next, a normal mode that is a normal operation of the ECU 10, the G sensor modules 20 to 20c, and the squib modules 30 to 30g will be described with reference to FIGS. 14, 15, 17, 18, and 25. FIG. FIG. 25 shows transmission timings of the communication control circuit 15 of the ECU 10 and the communication control circuit 23 of each G sensor module in the normal mode.
[0059]
  The master communication control circuit 15 uses the microcomputer to set n = 1 and flag f = 0 in step 111 of FIG. 14, and then in step 112, resets the timer to start timing. In step 113, an acceleration data request command is transmitted to the power signal line 42 by broadcast communication. Note that f = 0 indicates that no self-diagnosis signal is transmitted.
[0060]
  In the communication control circuit 15, the microcomputer receives acceleration data from the power supply signal line 42 in step 114, and in step 115, it is determined whether or not the acceleration data has been received. If the determination in step 115 is NO, step 114 is repeated until YES is determined in step 115.
[0061]
  Thereafter, it is determined in step 116 whether an ignition instruction is issued from the collision determination circuit 16 to the communication control circuit 15. If the determination in step 116 is NO because there is no ignition instruction, it is determined YES in step 117 (see FIG. 15) based on f = 0. In step 118, a self-diagnosis command is sent to the slave corresponding to n. The signal is transmitted through the power signal line 42, and in step 119, f = 1 is set.
[0062]
  When the time measured by the timer exceeds T0 seconds, the determination at step 120 is YES, and the processing after step 112 is similarly repeated. Thereafter, if NO is determined based on f = 1 in step 117, the self-diagnosis result of the slave corresponding to n is received in step 121. If there is an abnormality in the self-diagnosis result, the determination in step 122 is YES, and a warning is displayed (for example, a warning lamp is turned on) in step 123. Note that this warning lamp is provided in a part such as an instrument panel where the user's eyes can reach.
[0063]
  On the other hand, if the determination in step 122 is NO, in step 124, f = 0 is set, and in step 125, it is determined whether n = M + N. If n = M + N is not satisfied, the determination in step 125 is NO, and n = n + 1 is added and updated in step 126. This process is repeated until YES is determined in step 125. If YES is determined in step 125, n = 1 is set in step 127.
[0064]
  If the determination in step 116 is YES because there is an ignition instruction, the ignition command is transmitted to the power signal line 42 by broadcast communication in step 128, and the flag f = 0 is set in step 129.
[0065]
  The communication control circuit 23 of the G sensor module sets all of the self-diagnosis flag d, the last flag d1 and the acceleration data transmission flag e to 0 in step 204 of FIG. The signal on 42 (signal other than the ignition command) is received. Next, since d = 0, the determination in step 206 is NO, and if the received signal in step 205 has a message logical address = n or a broadcast communication signal, it is determined as YES in step 207. . Note that d1 = 1 indicates that the slave is the last, and e = 1 indicates that the slave has already transmitted the acceleration data.
[0066]
  Next, in step 208 of FIG. 18, if there is no acceleration data request command in the received signal in step 205, NO is determined. In step 209, if the received signal in step 205 has a self-diagnosis command, YES is determined. Determined. In step 210, self-diagnosis is started, d = 1 is set in step 211, and NO is determined in step 212 based on e = 0. On the other hand, if e = 1 at the present stage, the determination at step 212 is YES, and d1 = 1 is set at step 213.
[0067]
  On the other hand, if there is an acceleration data request command in the received signal in step 205 in step 208, YES is determined, and in step 214, the acceleration data is sampled. Thereafter, if the current G sensor module is the first one (G sensor module 20), since n = 1, the determination in step 215 is YES.
[0068]
  On the other hand, when the determination in step 215 is NO, in step 216, the signal on the power supply signal line 42 is received by the communication control circuit 23 with the microcomputer. If the message logical address is not n−1 at this stage, the determination in step 217 is NO, and the processing through steps 215, 216, and 217 is repeated until the message logical address = n−1. Here, the determination of YES in step 217 means that n corresponding to the current G sensor module has been reached.
[0069]
  After step 217, the sampled acceleration data is encoded in step 214 and transmitted to the power signal line 42. Then, after setting e = 1 in step 219, it is determined in step 220 whether d = 1 and d1 = 1. Here, if d = 1 and d1 = 1, the determination in step 220 is YES, and in step 221, the self-diagnosis result in step 210 is sent to the power signal line 42 by the communication control circuit 23 using the microcomputer. Sent. Thereafter, in step 222, d = 0 is set. If NO is determined in step 220, the processes in both steps 221 and 222 are skipped.
[0070]
  If the determination in step 207 is NO after determining NO in step 206 as described above, in step 223, any of logical addresses 1 to n is set as the logical address a of the microcomputer of the communication control circuit 23. In step 224, e = 0 is set.
[0071]
  If the determination in step 206 is YES after the processing in step 205 as described above, it is determined in step 225 whether or not the logical address of the message = a. If the logical address is a, the determination in step 225 is YES, and in step 226, the communication control circuit 23 transmits the self-diagnosis result to the power supply signal line 42 by the microcomputer. Next, d = 0 is set in step 227.
[0072]
  The above-described normal mode will be described in summary with reference to FIG. 25. When the ECU 10 serving as the master transmits an acceleration request command by broadcast communication using the communication control circuit 15, each G sensor module receives the transmission command and samples acceleration data. Are transmitted as acceleration data (digital data) sampled in the order of logical addresses.
[0073]
  The master transmits a self-diagnosis command to a specific slave having the logical address n after reception of all acceleration data is completed. The designated slave executes self-diagnosis and enters a state of waiting for self-diagnosis result transmission. In parallel with this, the master transmits an acceleration data request command again by broadcast communication. Similarly, the G sensor module transmits acceleration data sampled in the order of logical addresses. The slave requested for self-diagnosis transmits the self-diagnosis result after the last G sensor module transmits.
[0074]
  The cycle from the start of the acceleration data request command by broadcast communication to the transmission of the acceleration data request command again is defined as one cycle (see FIG. 25), and the time interval from the master or each slave transmitting until the next transmission is transmitted. This is called a frame. One cycle is composed of N + 2 frames because there are N G sensor modules. If the acceleration data request command is frame 0, the self-diagnosis request and the result are transmitted in frame N + 1. The time interval of one cycle is fixed at T0 seconds. T0 is determined by the required frequency bandwidth of acceleration.
(3) Ignition mode
  Next, the operation from the collision detection of the passenger car to the ignition of the squib will be described as an ignition mode with reference to FIG. 21, FIG. 22, and FIG.
[0075]
  The communication control circuit 36 of the squib module sets the self-diagnosis flag d = 0 in step 308 of FIG. 21 by the microcomputer. In step 309, the signal on the power supply signal line 42 is received by the communication control circuit 36 using the microcomputer. At this stage, since d = 0, NO is determined in step 310, and in step 311, the logical address of the message in the signal on the power supply signal line 42 is m or a signal on the power supply signal line 42 is determined. Is determined as YES when a broadcast communication signal is included.
[0076]
  Thereafter, in step 312, it is determined whether the signal voltage in the signal on the power signal line 42 is at the ignition level. If the signal voltage is not at the ignition level, it is determined in step 313 whether or not there is a self-diagnosis command in the signal on the power supply signal line 42. If the determination in step 313 is YES, in step 314, the microcomputer of the communication control circuit 36 starts self-diagnosis. In step 315, d = 1 is set.
[0077]
  As described above, after the determination in step 310 is NO, if the determination in step 311 is NO, in step 316, any one of logical addresses 1 to n is set as the logical address a in the memory of the microcomputer of the communication control circuit 36. Stored.
[0078]
  If the determination in step 310 is YES after the processing in step 309 as described above, it is determined in step 317 whether or not the logical address of the message = a. Here, if the determination in step 317 is YES, it is determined in step 318 whether there is a signal on the power signal line 42. If not, the determination in step 318 is NO, and in step 319, The communication control circuit 36 transmits the self-diagnosis result to the power signal line 42 by the microcomputer. After step 319, d = 0 is set in step 320.
[0079]
  In addition, if the determination in step 312 is YES after the determination of YES in step 311 as described above, whether or not there is an ignition command in the signal on the power supply signal line 42 in step 321. Is determined. Here, if the determination in step 321 is YES due to the presence of the ignition command, in step 322, the collision mode in the message included in the signal on the power supply signal line 42 is determined in the microcomputer memory of the communication control circuit 36. Matches the expansion attribute of On the other hand, when the determination in step 321 is NO, the process returns to step 309 without performing step 322.
[0080]
  As a result of the collation in step 322, it is determined in step 323 whether or not the collision mode is a collision mode in which the airbag is to be deployed. In step 324, the ignition switch 38 is turned on by the communication control circuit 36 with the microcomputer.
[0081]
  On the other hand, when the acceleration level determination circuit 37 of the communication control circuit 36 receives acceleration data from the power supply signal line 42 through the driver receiver 33 and the data conversion circuit 35, the acceleration level determination circuit 37 indicates that the level of the acceleration data is that of the passenger car. It is determined whether or not it matches the acceleration level representing the collision. If this determination is a match, the ignition switch 39 is turned on by the acceleration level determination circuit 37. As described above, when both ignition switches 38 and 39 are turned on, the squib 39a is ignited and the airbag of the corresponding airbag mechanism is deployed.
[0082]
  The ignition mode will be described in summary with reference to FIG. 26. The master collision determination circuit 16 analyzes the acceleration data sent from each G sensor module, determines the presence or absence of a collision of the passenger car, and has a collision. In this case, data indicating what type of collision is output to the communication control circuit 15 at an arbitrary timing. The communication control circuit 15 continues to receive acceleration data without changing the basic cycle and frame framework even if it receives data representing the collision mode from the microcomputer, and sends the ignition command at frame N + 1. Do.
[0083]
  Here, since the message including the ignition command also includes information indicating the collision type, the communication control circuit 36 of the squib module that has received this message uses the microcomputer to determine whether the signal voltage is the ignition level (voltage range C). It is determined whether or not the command is an ignition command. If the command is an ignition command, the collision mode is compared with the expansion attribute in the memory of the microcomputer. Switch 38 is turned on.
[0084]
  The acceleration level determination circuit 37 of the squib module reads the acceleration data on the power signal line 42 through the driver receiver 33 and the data conversion circuit 35, and the level of the acceleration data exceeds a predetermined level representing the collision of the passenger car. If so, the ignition switch 39 is turned on. Thus, when both ignition switches 38 and 39 are turned on, the squib 39a is ignited.
[0085]
  As a result, in the present embodiment, no matter what single failure occurs in the airbag system, erroneous ignition is reliably prevented in any of the squibs of the airbag system, thereby preventing malfunction of the airbag mechanism. It is possible.
[0086]
  Further, since the airbag deployment state of the airbag mechanism is controlled based on the collision modes 1 to P corresponding to each squib module as described above, the acceleration is generated according to the acceleration generated at the location of each squib module with respect to the passenger car. The airbag deployment state of the airbag mechanism can be ensured.
[0087]
  Note that the airbag system described in the above embodiment has a minimum necessary configuration when a mechanical safing sensor is not used. With such a configuration, the effects of the above embodiment are achieved. It can be done.
[0088]
  In implementing the present invention, the present invention may be applied to an occupant protection system such as a belt tensioner for a seat of the passenger car without being limited to the airbag system.
[0089]
  Further, in the implementation of the present invention, the collision determination circuit 36 of each squib module 30 to 30g may be eliminated.
[0090]
  Further, in the implementation of the present invention, the collision determination circuit 16 of the ECU 10 may be eliminated.
[0091]
  In implementing the present invention, the number of G sensor modules and squib modules need not be limited to the number described in the above embodiment, and may be changed as appropriate.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an embodiment in which an airbag system according to the present invention is provided in a passenger car.
FIG. 2 is a block diagram of the airbag system.
FIG. 3 is a detailed block diagram showing a configuration of the ECU 10 of FIG.
FIG. 4 is a waveform diagram of each voltage range A to C;
FIG. 5 is a diagram showing a physical address, a logical address, a development attribute, and state information corresponding to each slave stored in advance in the memory of the microcomputer of the communication control circuit of the ECU 10;
FIG. 6 is a detailed block diagram showing a configuration of each G sensor module.
FIG. 7 is a diagram showing physical addresses and logical addresses stored in a microcomputer memory of a communication control circuit of each G sensor module.
FIG. 8 is a detailed block diagram showing the configuration of each squib module.
FIG. 9 is a diagram showing physical addresses, logical addresses, and development attributes stored in a microcomputer memory of a communication control circuit of each squib module.
FIG. 10 is a diagram illustrating the format of the development attribute by the relationship between each squib module and each collision mode 1 to P.
FIG. 11 is a diagram illustrating a configuration of a message from a master to a slave and a message from a slave to a master.
FIG. 12 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of the ECU 10;
13 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of the ECU 10. FIG.
14 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of the ECU 10. FIG.
15 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of the ECU 10. FIG.
FIG. 16 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of each G sensor module.
FIG. 17 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of each G sensor module.
FIG. 18 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of each G sensor module.
FIG. 19 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of each squib module.
FIG. 20 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of each squib module.
FIG. 21 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of each squib module.
FIG. 22 is a part of a flowchart showing the operation of the microcomputer of the communication control circuit of each squib module.
FIG. 23 is a timing chart showing message exchange between a master and a slave in a slave corresponding to a logical address n.
FIG. 24 is a diagram illustrating a configuration of messages n1, n2, n1 ′, and n2 ′.
FIG. 25 is a timing chart showing exchange of data for each frame between the ECU 10 and each G sensor module in the normal mode.
FIG. 26 is a timing chart showing exchange of data for each frame between the ECU 10 and each G sensor module in the ignition mode.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 10 ... ECU, 15, 23, 36 ... Communication control circuit, 16 ... Collision determination circuit, 20 thru | or 20c ... G sensor module, 21 ... Acceleration sensor, 30 thru | or 30g ... Squib module, 37 ... Acceleration level determination circuit, 38, 39 ... Ignition switch, 39a ... Squib, 40 ... Serial communication bus.

Claims (7)

A plurality of occupant protection mechanisms, a plurality of acceleration sensor modules (20 to 20c), a plurality of squib modules (30 to 30g) and an electronic control device (10) mounted at different positions of the vehicle, and each of the acceleration sensors A vehicle occupant protection system comprising a module, a serial communication bus (40) formed by connecting each squib module and the electronic control unit,
Each of the plurality of acceleration sensor modules includes an acceleration sensor (21) that detects acceleration of the vehicle at different positions of the vehicle, and the serial communication bus using acceleration detected by the acceleration sensor as acceleration data for a corresponding squib module. Transmission means (23, 218) for transmitting to
The electronic control unit determines the presence or absence of a vehicle collision based on the acceleration data for the corresponding squib module on the serial communication bus, and transmits the determination result to the serial communication bus as determination data for the corresponding squib module. With collision determination means (15, 16, 116),
Each of the plurality of squib modules is a squib (39a) that is driven when operating a corresponding occupant protection mechanism among the plurality of occupant protection mechanisms, and only when both are connected in series to the squib and are turned on. Collision determination for determining whether or not there is a vehicle collision based on the acceleration data for the corresponding squib module on the serial communication bus and turning on one of the ignition switches (38, 39) for driving the squib Means (37),
The vehicle occupant protection system in which the other ignition switch among the ignition switches is turned on when the determination data for the corresponding squib module on the serial communication bus indicates a vehicle collision. Collision determination means of the electronic control device, the corresponding squib module determination data, to claim 1, characterized in that transmitted to the serial communication bus in a different signal form and said corresponding squib module acceleration data The vehicle occupant protection system described. The vehicle occupant protection system according to claim 2 , wherein the signal form of the corresponding squib module determination data has a voltage amplitude different from that of the corresponding squib module acceleration data. The vehicle occupant protection system according to any one of claims 1 to 3 , wherein the collision determination means of the electronic control device determines including a vehicle collision mode. The electronic control device includes ignition command transmission means (128) for transmitting a corresponding squib module ignition command for any of the plurality of squib modules to the serial communication bus,
Each of the plurality of squib modules receives the ignition command for the corresponding squib module on the serial communication bus, and determines whether or not there is a vehicle collision based on the determination data for the corresponding squib module on the serial communication bus. The vehicle according to any one of claims 1 to 4, further comprising another collision determination means (321 to 324) that determines and determines that there is a collision and turns on the other ignition switch. Crew protection system. 6. The vehicle occupant protection system according to claim 5 , wherein one of the both collision determination units of the plurality of squib modules includes a vehicle collision mode. Immediately after the start of the operation, the electronic control device transmits information to the serial communication bus for information that one of the collision determination means of each of the plurality of squib modules includes, including the vehicle collision mode. A transmission means (104),
6. The vehicle according to claim 5 , wherein one of the both collision determination means of the plurality of squib modules makes a determination including a vehicle collision mode based on the information on the serial communication bus. Crew protection system.

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