JP2006193043A - Communication system for occupant protection unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system for an occupant protection unit which communication system suppresses a delay in communication of sending startup information for starting the occupant protection unit. <P>SOLUTION: The communication system comprises a main ECU 100 which transmits startup information for starting the occupant protection units 30 to 33 via a first transmission line 60, and sub-ECUs 100a to 100d which judges on the abnormality of information transmission via the first transmission line 60, and transmits information of the judgement to the main ECU 100. The sub-EUCs 100a to 100d transmits the information of judgement via a second transmission line 70 different from the first transmission line 60. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication system for an occupant protection device, and more particularly to a communication system for activation of an occupant protection device.

Conventionally, an ECU system in which a plurality of ECUs are connected via a communication line is known (for example, see Patent Document 1). This ECU system transmits a command for instructing other ECUs to store vehicle information via a communication line when the operation of a controlled device controlled by a certain ECU is detected. Thus, information possessed by a plurality of ECUs is utilized to enhance the abnormality analysis effect of the controlled device.
JP 2002-193070 A

  By the way, in recent years, the number of occupant protection devices mounted on vehicles has been increasing in order to improve occupant protection performance. However, as the number of occupant protection devices increases, the functions to be controlled increase and become complicated. Therefore, when one ECU controls all of these functions, there arises a problem such as vehicle mountability such as ECU size increase. There is a risk that. Therefore, a distributed system has been considered in which these functions are distributed to ECUs provided in each part of the vehicle and each ECU is connected via a communication line.

  However, when using a communication line to which a plurality of ECUs are connected, there is a possibility that communication delay of activation information that activates the occupant protection device may occur due to overlapping with communication performed by other ECUs. In this regard, the above-described conventional technology discloses an ECU system when applied to an airbag ECU. However, the occurrence of the same communication delay is not assumed, and this is not an ideal configuration.

  Accordingly, an object of the present invention is to provide a communication system for an occupant protection device that suppresses a communication delay of activation information that activates the occupant protection device.

In order to solve the above problems, according to one aspect of the present invention,
A first control unit for transmitting activation information for activating the occupant protection device via the first transmission line;
An occupant protection device communication system comprising: a second control unit that performs abnormality determination on transmission via the first transmission path and transmits the determination information to the first control unit;
The second control unit provides a communication system for an occupant protection device, wherein the determination information is transmitted via a second transmission path different from the first transmission path.

  According to this aspect, since the information that the second control unit has determined to be abnormal is not transmitted to the first control unit via the first transmission path, the communication load of the first transmission path is reduced by the determination information, Communication delay of activation information can be suppressed.

  In this aspect, it is preferable that the second transmission path is a bidirectional communication system. Thus, in order to transmit information including at least the activation information among the information transmitted to the second control unit via the first transmission path and to transmit other information via the second transmission path, The communication load of one transmission path is reduced by the amount of information via the second transmission path, and the communication delay of activation information can be suppressed.

  The first transmission path is preferably a unidirectional communication system from the first control unit to the second control unit. Accordingly, since all information transmitted from the second control unit to the first control unit is not transmitted via the first transmission path, it is possible to suppress a communication delay of the activation information. In particular, if the first transmission path is a dedicated transmission path for activation information and all information other than the activation information is transmitted via the second transmission path, the activation information can be transmitted without delay.

  ADVANTAGE OF THE INVENTION According to this invention, the communication delay of the starting information which starts a passenger | crew protection apparatus can be suppressed.

  The best mode for carrying out the present invention will be described below. FIG. 1 is a diagram showing a configuration of a communication system of an occupant protection device according to the present invention.

  The front airbag sensor 20 is attached to the front portion of the vehicle and senses an impact on the front portion of the vehicle. The side airbag sensor 21 is attached to the lower part of the center pillar on the left and right sides of the vehicle, and senses an impact on the side of the vehicle. The side airbag sensor rear 22 is attached to the lower part of the C pillar on the left and right sides of the vehicle and senses an impact on the side of the vehicle.

  As these airbag sensors, piezoelectric G sensors or semiconductor G sensors are used. The piezoelectric G sensor is a device in which a piezoelectric element is attached to a plate that senses acceleration / deceleration, and a voltage value corresponding to the amount of deformation of the piezoelectric element due to a collision is detected. On the other hand, the semiconductor G sensor detects a voltage value corresponding to the deformation amount of the strain gauge due to a collision.

The seat position sensor 23 is attached to the seat rail portion and detects the seat slide position. The occupant's posture is detected based on the seat slide position. The buckle switch 24 detects whether or not the seat belt is worn.
The main ECU 100 performs activation determination (ignition determination) of each occupant protection device, which will be described later, based on, for example, detection values by these sensors 20 to 24 and detection values by a safing sensor (not shown) in the main ECU 100. That is, the main ECU 100 can recognize the occupant's seating state with the seat position sensor 23 and the buckle switch 24, and determines that the occupant protection device can be ignited based on a predetermined ignition determination condition. For example, when the detection values of the front airbag sensor 20 and the safing sensor are equal to or greater than a predetermined value and both are turned ON, it is determined that the airbag 30 in the driver seat / passenger seat can be ignited.

  In addition to the airbag 30, the occupant protection device includes, for example, a side airbag 31 that reduces and absorbs impact on the occupant side, a seat belt 32 with a pretensioner that enhances the occupant's restraining effect, A curtain shield airbag 33 that relieves and absorbs shocks can be used. For these occupant protection devices as well, the main ECU 100 makes an ignition determination based on the values detected by the safing sensor and the sensors 20 to 24 in the same manner as described above.

  However, in the ECU system in which each occupant protection device is controlled by one ECU as shown in FIG. 2, problems such as vehicle mountability arise as the number of occupant protection devices increases as described above. Therefore, the ECU system of the present invention distributes the ECU functions by providing the sub ECUs 100a to 100d between the main ECU 100 and the occupant protection devices 30 to 33. Each occupant protection device and each ECU are connected via a communication line. Each sub-ECU includes an abnormality determination (diagnostic) circuit, a driving circuit for each occupant protection device, a control program thereof, and the like, and functions are distributed both in hardware and software.

  By dispersing in this way, the size of each main ECU 100 is prevented from being increased, and each sub-ECU is also reduced in size, so that the vehicle mountability of each ECU is improved. For example, the main ECU 100 is installed in the front part of the vehicle, and each sub ECU is installed in the rear part of the vehicle. And it becomes possible to mount in a smaller space. Furthermore, it is possible to reduce the product number of the main ECU 100 that has been individually set due to the difference in the equipment of the occupant protection device for each vehicle type and specification, and to reduce the cost of the entire occupant protection system.

  In this distributed ECU system, when the main ECU 100 determines that ignition is possible as described above, activation information for activating (igniting) each occupant protection device assigned to each sub ECU via the ignition communication line 60. (Ignition information) is transmitted. Each sub-ECU drives an occupant protection device assigned based on the received ignition information. For example, the sub ECU 100 a drives the airbag 30 based on the ignition information of the airbag 30 from the main ECU 100. The sub ECU may also include sensors such as the rear seat buckle switch 25 and the rear seat occupant detection sensor 26 for detecting the occupant's seating. For example, the sub ECU 100c determines whether the rear seat buckle switch 25 or the rear seat occupant detection sensor 26 for detecting the seating of the occupant and the ignition information of the seat belt with the front seat pretensioner from the main ECU 100 are used. Drive seat belt with tensioner.

  In FIG. 1, the ignition communication line 60 is branched to each sub-ECU. However, the main ECU 100 and each sub-ECU may be connected one-to-one. Further, the ignition information transmitted from the main ECU 100 may be transmitted as it is detected value information from the sensors 20 to 24 and the safing sensor, or based on the sensors 20 to 24 and the safing sensor as described above. The ignition information that is the result of the ignition determination may be transmitted. In the former case, each sub-ECU performs ignition determination of the occupant protection device assigned to each sub ECU based on the detected value information and the detected values by the sensors 25 and 26.

  Each sub-ECU has a function of performing diagnosis determination regarding transmission via the ignition communication line 60 and diagnosis determination within itself. Diagnosis for transmission via the ignition communication line 60 includes, for example, diagnosis (disconnection, power supply (+ B) short, ground (GND) short) determination of the ignition communication line 60, and from the main ECU 100 via the ignition communication line 60. Diagnosis of information to be transmitted can be mentioned.

  The diagnosis determination of the ignition communication line 60 is, for example, when predetermined check information is transmitted from the main ECU 100 via the ignition communication line 60 at regular intervals, and the check information is not received (for example, continuously for a predetermined time). When the reception cannot be confirmed), each sub ECU determines that the ignition communication line 60 is abnormal.

  The diagnosis determination of information transmitted from the main ECU 100 via the ignition communication line 60 means that, for example, each sub-ECU monitors the abnormality of the information itself transmitted from the main ECU 100 to the main ECU 100 that is the transmission source. Determine whether there is an abnormality.

  Each sub-ECU may have a function of determining a diagnosis (disconnection, + B short, GND short) of the communication lines 50a to 50d.

  However, when using a communication line to which a plurality of ECUs are connected, there is a possibility that a communication delay of ignition information that activates the occupant protection device may occur due to overlapping with communication performed by other ECUs. For example, when the determination information, which is a result of the diagnosis determination by each sub ECU, is transmitted to the main ECU 100 as a response, if it is transmitted via the ignition communication line 60, it overlaps with the transmission timing of the ignition information, which is an important signal for passenger safety. Therefore, there is a possibility that communication delay of ignition information occurs.

  Therefore, the communication system of the occupant protection device of the present invention is newly provided with a diagnosis communication line 70 for transmitting diagnosis determination information different from the ignition communication line 60. The diagnosis communication line 70 is a local communication line to which only the main ECU 100 and each sub ECU are connected. Accordingly, each sub ECU transmits diagnosis determination information to the main ECU 100 not via the ignition communication line 60 but via the diagnosis communication line 70, so that the ignition communication line 60 is compared with a case where transmission is made via the ignition communication line 60. Communication load is reduced by the diagnosis determination information, and communication delay of ignition information can be suppressed.

  Further, the main ECU 100 determines whether or not there is an abnormality in the transmission via the ignition communication line 60 based on the diagnosis determination information received via the diagnosis communication line 70. When the diagnosis determination information is not received (for example, when reception cannot be confirmed continuously for a predetermined time), the main ECU 100 determines that there is an abnormality (disconnection, + B short, GND short) in the diagnosis communication line 70. The main ECU 100 acquires the diagnosis determination result of the communication lines 50a to 50d by each sub-ECU based on the information received via the diagnosis communication line 70, and whether or not each sub-ECU itself has an abnormality. It may be judged.

  By the way, the information transmitted from the main ECU 100 to each sub-ECU is not limited to the ignition information described above. There are determination information (for example, diagnosis determination information of the communication lines 40a to 40e) determined by the main ECU 100 and other control information. At this time, if the transmission is performed via the ignition communication line 60, there is a possibility that a communication delay of the ignition information may occur due to overlapping with the transmission timing of the ignition information.

  Therefore, in the communication system of the occupant protection device of the present invention, the diagnostic communication line 70 is a bidirectional communication system that allows the main ECU 100 and each sub ECU to transmit and receive each other. Accordingly, information including at least start-up information among information transmitted to each sub ECU is transmitted via the ignition communication line 60, and other information is transmitted via the diagnosis communication line 70. The communication load of 60 is reduced by the amount of information via the diagnostic communication line 70, and communication delay of ignition information can be suppressed.

  Furthermore, if information transmitted from each sub-ECU to the main ECU 100 is transmitted via the ignition communication line 60, there is a possibility that a communication delay of the ignition information occurs due to overlapping with the transmission timing of the ignition information.

  Therefore, the communication system of the occupant protection device of the present invention employs a unidirectional communication system in which the ignition communication line 60 can be transmitted only in the direction from the main ECU 100 to each sub ECU. Accordingly, since all information transmitted from each sub ECU to the main ECU 100 is not transmitted via the ignition communication line 60, a communication delay of the ignition information can be suppressed. In particular, if the ignition communication line 60 is a dedicated line for ignition information and all information other than the ignition information is transmitted via the diagnostic communication line 70, the ignition information can be transmitted without delay.

  Note that communication between the main ECU 100 and each sub-ECU is performed by, for example, a CAN protocol. FIG. 3 is a diagram showing the data contents of one frame transmitted by each ECU constituting the CAN communication system. Each frame transmitted as data by each ECU stores an ID field for storing its own ECU identification number, a control field for storing the data length of the data field, and data to be transmitted that varies in 0 to 8 bytes. A data field and a CRC field for storing data for performing a cyclic code redundancy check. Each ECU has a transmission rate of, for example, 500 kbps. When the data length of the data field is 8 bytes, one frame data of about 120 bits can be transmitted and received in about 250 μs. In this data field, ignition information, diagnosis determination information and other control information are stored.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, if it is impossible to set the local diagnostic communication line 70, information other than the ignition information may be transmitted via the existing in-vehicle LAN.

It is the figure which showed one structure of the communication system of the passenger | crew protection apparatus of this invention. It is the figure which showed one structure of the communication system of the passenger | crew protection device controlled by one ECU. The figure showing the data content of 1 frame which each ECU which comprises a CAN communication system transmits is shown.

Explanation of symbols

10 ECU
60 ignition communication line 70 diagnosis communication line 100 main ECU
100a to 100d Sub ECU

Claims (3)

A first control unit for transmitting activation information for activating the occupant protection device via the first transmission line;
An occupant protection device communication system comprising: a second control unit that performs abnormality determination on transmission via the first transmission path and transmits the determination information to the first control unit;
The communication system for an occupant protection device, wherein the second control unit transmits the determination information via a second transmission path different from the first transmission path.   The occupant protection device communication system according to claim 1, wherein the second transmission path is a two-way communication system.   The occupant protection device communication system according to claim 1 or 2, wherein the first transmission path is a unidirectional communication system from the first control unit to the second control unit.

Images