COMMUNICATION SYSTEM FOR A PASSENGER PROTECTION SYSTEM

• US 20120136541A1
• Filed: 11/22/2011
• Published: 05/31/2012
• Est. Priority Date: 11/25/2010
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Inamoto, Takashi
• Granted Patent: US 8,996,256 B2
• Time in Patent Office: Days
• US Class Current: 701/45
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: B60R 21/0173 Diagnostic or recording means therefor

Abstract

In each sensor unit, when a sensor control unit cannot detect current flowing to an output side, its address is set to the same address as a sensor unit of the last stage. In an ECU, if the set address and characteristic information of each sensor unit are not stored in a memory unit when the set addresses and the characteristic information of all the sensor units are received by an ECU control unit, the received set addresses and the characteristic information are stored. A failure check unit checks received characteristic information received by the ECU control unit with characteristic information stored in the memory unit. If one characteristic information is in disagreement, a sensor unit having such characteristic information is determined to be failing. If plural characteristic information are in disagreement, a sensor unit having characteristic information and closest to the ECU is determined to be failing.

Claims

1. A communication device for a passenger protection system comprising:

an ECU for controlling a passenger protection device, which protects a passenger at time of vehicle collision; and

a plurality of sensor units connected to the ECU in a daisy chain form for detecting acceleration of the vehicle and transmitting acceleration signals to the ECU,

wherein the sensor units, after being initialized by setting of respective set addresses in correspondence to address setting instructions of the ECU, transmit the set addresses and characteristic information of the respective sensor units, and

wherein the ECU includes a memory unit and a failure check unit,

the memory unit storing as correspondence information, in which the characteristic information transmitted from the sensor units are associated with the set addresses, respectively, and

the failure check unit checking up the characteristic information transmitted from the sensor units with the correspondence information with respect to each of the set addresses, if the characteristic information are stored in the memory unit, and determining that the sensor unit having the characteristic information, which is in disagreement with the correspondence information as a result of checkup, is failing.

2. The communication device for a passenger protection system according to claim 1, wherein:

the failure check unit determines that, if more than one sensor units have the characteristic information, which are in disagreement with the correspondence information, a sensor unit closest to the ECU among the more than one sensor units is failing.

3. The communication device for a passenger protection system according to claim 1, wherein:

the ECU further includes a control unit, which stores the characteristic information transmitted from the sensor unit as the correspondence information associated with the set address, if the correspondence information is not stored in the memory unit.

4. The communication device for a passenger protection system according to claim 1, wherein:

the failure check unit determines that, if the set addresses and the characteristic information are not received from all of the sensor units and the set addresses and the characteristic information of each sensor unit are not stored in the memory unit, a specific failure, which is other than the failure of the sensor units, is present.

5. The communication device for a passenger protection system according to claim 1, wherein:

the control unit updates, upon reception of the set addresses and the characteristic information from all of the sensor units, characteristic information by writing, over the characteristic information stored in the memory unit and in disagreement, the characteristic information, which is determined to be in disagreement with the characteristic information stored in the memory unit among the received characteristic information of all the sensor units.

6. The communication device for a passenger protection system according to claim 1, wherein:

the failure check unit determines that, if a set address count of the set addresses received by the control unit and an initialized sensor count of initialized sensor units counted up at reception of the characteristic information with the set address are equal and less than a count of all of the sensor units, an open-failure indicating disconnection is present between the sensor unit in the last stage included in the initialized sensor count and the sensor unit subsequent to the last stage.

7. The communication device for a passenger protection system according to claim 1, wherein:

each of the sensor units includes a failure detection unit, which detects current flowing in the sensor unit when the sensor unit is activated, and determines presence and absence of the failure if a detected current value is less than and equal to or greater than a predetermined value, respectively; and

each of the sensor units controls the sensor unit to an off-state without performing the address setting, when the failure detection unit determines that a failure is present.

8. The communication device for a passenger protection system according to claim 2, wherein:

the ECU further includes a control unit, which stores the characteristic information transmitted from the sensor unit as the correspondence information associated with the set address, if the correspondence information is not stored in the memory unit.

9. The communication device for a passenger protection system according to claim 2, wherein:

the failure check unit determines that, if the set addresses and the characteristic information are not received from all of the sensor units and the set addresses and the characteristic information of each sensor unit are not stored in the memory unit, a specific failure, which is other than the failure of the sensor units, is present.

10. The communication device for a passenger protection system according to claim 2, wherein:

the control unit updates, upon reception of the set addresses and the characteristic information from all of the sensor units, characteristic information by writing, over the characteristic information stored in the memory unit and in disagreement, the characteristic information, which is determined to be in disagreement with the characteristic information stored in the memory unit among the received characteristic information of all the sensor units.

11. The communication device for a passenger protection system according to claim 2, wherein:

the failure check unit determines that, if a set address count of the set addresses received by the control unit and an initialized sensor count of initialized sensor units counted up at reception of the characteristic information with the set address are equal and less than a count of all of the sensor units, an open-failure indicating disconnection is present between the sensor unit in the last stage included in the initialized sensor count and the sensor unit subsequent to the last stage.

12. The communication device for a passenger protection system according to claim 2, wherein:

each of the sensor units includes a failure detection unit, which detects current flowing in the sensor unit when the sensor unit is activated, and determines presence and absence of the failure if a detected current value is less than and equal to or greater than a predetermined value, respectively; and

each of the sensor units controls the sensor unit to an off-state without performing the address setting, when the failure detection unit determines that a failure is present.

13. The communication device for a passenger protection system according to claim 3, wherein:

the failure check unit determines that, if the set addresses and the characteristic information are not received from all of the sensor units and the set addresses and the characteristic information of each sensor unit are not stored in the memory unit, a specific failure, which is other than the failure of the sensor units, is present.

14. The communication device for a passenger protection system according to claim 3, wherein:

the control unit updates, upon reception of the set addresses and the characteristic information from all of the sensor units, characteristic information by writing, over the characteristic information stored in the memory unit and in disagreement, the characteristic information, which is determined to be in disagreement with the characteristic information stored in the memory unit among the received characteristic information of all the sensor units.

15. The communication device for a passenger protection system according to claim 3, wherein:

the failure check unit determines that, if a set address count of the set addresses received by the control unit and an initialized sensor count of initialized sensor units counted up at reception of the characteristic information with the set address are equal and less than a count of all of the sensor units, an open-failure indicating disconnection is present between the sensor unit in the last stage included in the initialized sensor count and the sensor unit subsequent to the last stage;

each of the sensor units includes a failure detection unit, which detects current flowing in the sensor unit when the sensor unit is activated, and determines presence and absence of the failure if a detected current value is less than and equal to or greater than a predetermined value, respectively; and

each of the sensor units controls the sensor unit to an off-state without performing the address setting, when the failure detection unit determines that a failure is present.