JP2006047045A - Occupant detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an occupant detecting device capable of performing an occupant detection function satisfactorily by warming a sensor itself or its surroundings, even in a cryogenic environment. <P>SOLUTION: This occupant detecting device having an occupant detecting sensor for detecting an occupant on a seat and capable of solving former problems, is equipped with a heater having a function of warming at least the occupant detecting sensor, and a heater control means for controlling the heater so that the temperature of the occupant detection sensor or its surroundings may be a predetermined temperature value or higher. Namely, though the occupant detection function is usually prohibited to operate in the cryogenic environment being outside guarantee temperatures, the sensor itself or its surroundings can be warmed by operating a seat heater or the like, even if the temperature in a vehicle compartment is low and has not risen up to a guarantee temperature, and the occupant detection function is made satisfactorily operatable. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an occupant detection device that detects an occupant on a seat.

Conventionally, a seated occupant detection device that accurately detects the load of a seated occupant is known (for example, Patent Document 1). In this seat occupant detection device, when an occupant sits on a seat, a load corresponding to the weight of the occupant acts on the load sensor.
JP 2001-74543 A

  However, sensors used in general occupant detection devices, including load sensors used in the above-described seated occupant detection devices, have temperature characteristics. In an environment of extremely low temperature (for example, −40 ° C.) in a cold region or the like, the detection performance of the sensor tends to be worse than that at normal temperature. As a result, the occupant detection device cannot sufficiently exhibit its occupant detection function. Furthermore, since whether or not to deploy the airbag is determined based on the detection result of the occupant detection device, it is desirable to use the sensor in an environment where the temperature is as high as possible.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an occupant detection device in which an occupant detection function sufficiently works by warming the sensor itself or its surroundings even in a cryogenic environment.

In order to solve the above problems, according to one aspect of the present invention,
An occupant detection device having an occupant detection sensor for detecting an occupant on a seat,
A heater having a function of warming at least the occupant detection sensor;
There is provided an occupant detection device comprising: a heater control means for controlling the heater so that the occupant detection sensor or a temperature around the occupant detection sensor is equal to or higher than a predetermined temperature. In this case, the passenger detection sensor itself can be warmed up to a predetermined temperature in a short time by operating the heater even in a cold region or the like, where the passenger compartment is cold. In particular, occupant detection based on the detection result of the occupant detection sensor is preferably prohibited when the temperature of the occupant detection sensor or its surroundings is lower than the predetermined temperature. For example, the occupant detection function of the occupant detection device has been prohibited from operating in an extremely low temperature environment that is outside the guaranteed temperature of the occupant detection sensor. Since the temperature of the occupant detection sensor itself or its surroundings depends on the vehicle interior temperature, it is necessary for a long time until the vehicle interior temperature rises to the guaranteed temperature range, especially in extremely low temperature environments, and during that time the occupant detection function is activated. I couldn't. However, even when the passenger compartment temperature has not risen to the guaranteed temperature range, operating the heater can warm the passenger detection sensor itself or the surrounding temperature, and quickly and sufficiently detect the passenger. You will be able to work the function. It should be noted that the occupant detection sensor only needs to be warmed, so it may be warmed by a seat heater, or may be warmed by the warm air of an air conditioner.

  The predetermined temperature is preferably set based on a temperature region in which the detection performance of the occupant detection sensor is poor. Thereby, when the temperature of the occupant detection sensor or its surroundings is in a temperature range where the accuracy of the detection performance of the occupant detection sensor cannot be expected, the seat heater can be operated to increase the temperature to a temperature range where accuracy can be expected at an early stage. it can. Even if the occupant detection function is disabled because it is outside the guaranteed temperature, occupant detection can be started early.

  In particular, the occupant detection sensor may detect a weight applied to the seat as the occupant. In this case, an occupant on the seat is detected based on a detection result of a load sensor such as a strain gauge or a pressure sensor. By operating the seat heater, the load sensor itself or its surroundings can be warmed to a predetermined temperature, and the occupant detection function can be fully activated.

  Moreover, it is preferable that the heater control means controls the heater so that a time determined according to a temperature at which the heater starts operating elapses. In this case, based on the temperature at which the heater starts operating, for example, the heater operating time required to reach the guaranteed temperature range is known. Therefore, by controlling the operation of the heater so that the operation time elapses, the occupant detection function can be sufficiently activated by heating the occupant detection sensor itself or its surroundings even in an extremely low temperature environment.

  According to the present invention, even in an extremely low temperature environment, the occupant detection function can be sufficiently activated by warming the sensor itself or its surroundings.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a vehicle sectional view showing a system in which an occupant detection device according to an embodiment of the present invention is used. The system of the present embodiment is established by the relationship between the occupant detection device of the present invention and the airbag system. The occupant detection device is controlled by the occupant detection ECU 20, and the airbag system is controlled by the airbag ECU 12. For example, the passenger detection device detects whether or not an occupant is sitting in the passenger seat, thereby determining whether or not the airbag on the passenger seat side is allowed to deploy. The occupant detection device detects a load value or load distribution applied to the seat 10 to determine whether an adult is sitting or a child is sitting. Thereby, the deployment method (deployment direction, etc.) of the airbag is changed according to the seated occupant so that the seated occupant is appropriately protected. Note that the occupant detection device of the present invention is not limited to a system that is established in relation to the airbag system, and can be implemented in a different system in relation to other systems. For example, cooperative control with the air conditioning control system can be considered. The occupant detection device detects the occupant's seating status for each seat (driver's seat, front passenger seat, rear seat, etc.), and captures the seating status detection results for each seat into the air conditioning control system. The direction can be controlled.

  Now, a system when the occupant detection device of the present invention is applied to an airbag system will be described. An airbag module 14 and an indicator 16 are connected to the airbag ECU 12. The airbag module 14 and the indicator 16 are provided on the instrument panel 18 of the vehicle. The airbag module 14 operates when a predetermined operation signal is supplied from the airbag ECU 12. The indicator 16 is turned on when a predetermined lighting signal is supplied from the airbag ECU 12. The airbag ECU 12 lights the indicator 16 when the operation of the airbag module 14 is prohibited.

  One of the cases where the operation of the airbag module 14 is prohibited is when the occupant detection ECU 20 outputs an operation prohibition signal to the airbag ECU 12. The case where the occupant detection ECU 20 outputs the operation prohibition signal is, for example, when it is detected that no occupant is sitting on the seat, or when the occupant detection ECU 20 is in an extremely low temperature environment that is outside the guaranteed temperature. The reason for prohibiting the operation of the airbag module 14 in an extremely low temperature environment is that there is a problem in safety to operate it outside the guaranteed temperature range. In general, the ECU can operate up to around −40 ° C., but it is desirable that the environment in which the sensor is used be several tens of degrees higher than the temperature.

  The occupant detection ECU 20 is provided under the seat 10 and is connected to a load sensor 22 that is an occupant detection sensor that detects an occupant on the seat 10. The load sensor 22 is a film-like pressure sensor, for example, and is provided inside the seat 10. In this pressure sensor, the electrical resistance value of the sensing portion changes when a load is applied. The occupant detection ECU 20 can detect the presence / absence of an occupant on the seat 10 and the load value applied to the seat 10 by reading the electrical resistance value change in the sensing portion.

  A seat heater 24 is provided inside the seat 10. The seat heater 24 is known to enhance passenger comfort by warming the seat 10 because the seat 10 is cold during cold weather. The seat heater 24 makes it possible to adjust the temperature of the seat 10 according to the detection result of the internal temperature of the seat 10 by the in-seat temperature sensor 26. An occupant sitting on the seat 10 can adjust the seat 10 to a desired temperature by operating a seat heater manual operation switch or a temperature adjustment volume beside the seat 10, for example.

  Furthermore, the seat heater 24 can be operated not only by manual operation by the occupant but also by the occupant detection ECU 20. The occupant detection ECU 20 uses a seat heater based on the atmospheric temperature data in the vehicle interior detected by the occupant detection ECU internal temperature sensor 28 incorporated in the occupant detection ECU 20 and the internal temperature data of the seat 10 detected by the in-seat temperature sensor 26. The operation of 24 is controlled. Therefore, when a cryogenic temperature at which the temperature of the load sensor 22 or its surroundings is outside the guaranteed temperature of the load sensor 22 is detected by these temperature sensors, the occupant detection ECU 20 detects the air pressure from the airbag ECU 12 as described above. An operation inhibition signal for inhibiting the operation of the back module 14 is output.

  Now, an operation example of the occupant detection device will be described with reference to a flowchart. First, a first embodiment of the occupant detection device of the present invention will be described. In the first embodiment, the seat heater 24 is controlled based on the detection result of the in-seat temperature sensor 26. FIG. 2 is a flowchart showing the operation of the occupant detection device of the first embodiment. This flow starts when the occupant detection ECU 20 is activated. First, the internal temperature data of the sheet 10 is acquired by the in-sheet temperature sensor 26 (step 100). Then, the occupant detection ECU 20 determines whether or not the acquired temperature data is lower than the predetermined temperature β, and determines whether or not occupant detection is permitted (step 110). In the present embodiment, for example, if the temperature range in which the accuracy of the detection performance of the load sensor 22 can be expected is −10 ° C. or higher, the predetermined temperature β is set to −10 ° C. In step 110, if the acquired temperature data falls below −10 ° C., the occupant detection ECU 20 prohibits occupant detection determination (step 120), and if it is −10 ° C. or higher, the occupant detection ECU 20 permits occupant detection determination (step 140). ).

When the occupant detection determination is prohibited in step 120, the occupant detection ECU 20 activates the seat heater 24 (step 130). By operating the seat heater 24, the seat 10 is warmed and the load sensor 22 is also warmed. Until the internal temperature data of the seat 10 acquired by the in-seat temperature sensor 26 is −10 ° C. or higher, the occupant detection determination by the occupant detection ECU 20 is prohibited, and the operating state of the seat heater 24 by the occupant detection ECU 20 continues. further,
On the other hand, if the acquired temperature data is −10 ° C. or higher in step 110, the occupant detection ECU 20 permits occupant detection determination (step 140). The case where the acquired temperature data is −10 ° C. or higher means that the temperature around the temperature sensor 26 in the vehicle interior or in the seat is originally −10 ° C. or higher, or that the seat heater 24 is activated in step 130 to activate the seat. This is when the internal temperature of 10 rises to -10 ° C or higher.

  Thereafter, the occupant detection ECU 20 determines whether or not the seat heater manual operation switch is OFF (step 150). If it is not OFF (ON), the occupant detection ECU 20 does nothing and returns to the beginning of the flow. If it is off, the occupant detection ECU 20 turns off the seat heater 24 and returns to the beginning of the flow (step 160).

  The seat heater 24 can be controlled from the occupant detection ECU 20 side, or can be controlled from the occupant side using a seat heater manual operation switch or a temperature adjustment volume.

  Therefore, if it is determined in step 150 that the seat heater manual operation switch is not turned off (turned on), nothing is particularly done from the occupant detection ECU 20 side according to the occupant's intention to turn it on. . In other words, if the seat heater manual operation switch is ON, the seat heater 24 remains ON, and if the seat heater manual operation switch is OFF, the seat heater 24 remains OFF.

  On the other hand, if it is determined in step 150 that the seat heater manual operation switch is OFF, the seat heater 24 that has been turned ON by the occupant detection ECU 20 is turned on from the occupant detection ECU 20 side according to the occupant's intention to turn OFF. It will be turned off.

  Next, a second embodiment of the present invention will be described. In the second embodiment, the seat heater 24 is controlled based on the detection results of the in-seat temperature sensor 26 and the occupant detection ECU internal temperature sensor 28. FIG. 3 is a flowchart showing the operation of the occupant detection device of the second embodiment. This flow starts when the occupant detection ECU 20 is activated. First, atmospheric temperature data in the passenger compartment is acquired by the occupant detection ECU internal temperature sensor 28 (step 200).

  Then, the occupant detection ECU 20 determines whether or not the acquired ambient temperature data is below a predetermined temperature α (step 210). In this embodiment, for example, if the temperature range in which the accuracy of the detection performance of the load sensor 22 can be expected is −10 ° C. or higher, the predetermined temperature α is set to −10 ° C. In step 210, if the acquired ambient temperature data is −10 ° C. or higher, the temperature of the load sensor 22 is already expected to be high, so the occupant detection ECU 20 does nothing and returns to the beginning of the flow. If the acquired ambient temperature data is less than −10 ° C., the process proceeds to step 220.

  In step 220, the internal temperature data of the seat 10 is acquired by the in-sheet temperature sensor 26. Then, the occupant detection ECU 20 determines whether or not the acquired temperature data is lower than the predetermined temperature β, and determines whether or not occupant detection is permitted (step 230).

  At this time, the seat heater 24 does not directly warm the load sensor 22 but warms through the cushion of the seat 10, so the value of the in-seat temperature sensor 26 is not necessarily the value of the load sensor 22 as it is. Sometimes. Therefore, if the temperature range in which the accuracy of the detection performance of the load sensor 22 can be expected is −10 ° C. or higher, for example, +10 so that the temperature detected by the in-seat temperature sensor 26 becomes a temperature corresponding to −10 ° C. 0 ° C corrected by ° C is set as a predetermined temperature β. In step 230, if the acquired temperature data falls below 0 ° C, the occupant detection ECU 20 prohibits occupant detection determination (step 240), and if it is 0 ° C or higher, the occupant detection ECU 20 permits occupant detection determination (step 260).

  If the occupant detection determination is prohibited in step 240, the occupant detection ECU 20 activates the seat heater 24 (step 250). By operating the seat heater 24, the seat 10 is warmed and the load sensor 22 is also warmed. The occupant detection determination by the occupant detection ECU 20 is prohibited and the operating state of the seat heater 24 by the occupant detection ECU 20 continues until the internal temperature data of the seat 10 acquired by the in-seat temperature sensor 26 becomes 0 ° C. or higher.

  On the other hand, if the acquired temperature data is 0 ° C. or higher in step 230, the occupant detection ECU 20 permits occupant detection determination (step 260). The case where the acquired temperature data is 0 ° C. or higher means that the temperature around the temperature sensor 26 in the vehicle interior or the seat is originally 0 ° C. or higher, or that the seat heater 24 is activated in step 130 to activate the seat 10. This is when the internal temperature rises to 0 ° C. or higher.

  Thereafter, the occupant detection ECU 20 performs temperature correction on the occupant detection data (for example, load value data) detected by the load sensor 22 (step 270). For example, the correction coefficient between the detection temperature of the occupant detection ECU internal temperature sensor 28 and the actual temperature of the load sensor 22 is used as the correction coefficient A, and the correction coefficient between the detection temperature of the in-seat temperature sensor 26 and the actual temperature of the load sensor 22 is corrected. If the coefficient B is used, “temperature-corrected occupant detection data (load value data) = detected value of the load sensor 22 × (correction coefficient A + correction coefficient B)”.

  Then, the passenger detection ECU 20 determines whether or not the seat heater manual operation switch is OFF (step 280). If it is not OFF (ON), the occupant detection ECU 20 does nothing and returns to the beginning of the flow. If it is off, the occupant detection ECU 20 turns off the seat heater 24 and returns to the beginning of the flow (step 290). The meanings of steps 280 and 290 are the same as the contents described in the first embodiment.

  Next, a third embodiment of the present invention will be described. In the third embodiment, the seat heater 24 is controlled by obtaining the operating time of the seat heater 24 based on the detection result of the temperature sensor 28 in the occupant detection ECU. FIG. 4 is a flowchart showing the operation of the occupant detection device of the third embodiment. This flow starts when the occupant detection ECU 20 is activated. First, atmospheric temperature data in the passenger compartment is acquired by the occupant detection ECU internal temperature sensor 28 (step 300).

  Then, the occupant detection ECU 20 determines whether or not the acquired ambient temperature data is below a predetermined temperature α (step 310). In this embodiment, for example, if the temperature range in which the accuracy of the detection performance of the load sensor 22 can be expected is −10 ° C. or higher, the predetermined temperature α is set to −10 ° C. In step 310, if the acquired ambient temperature data is −10 ° C. or higher, the temperature of the load sensor 22 is already expected to be high, so the occupant detection ECU 20 returns to the beginning of the flow without doing anything. If the acquired ambient temperature data is less than −10 ° C., the process proceeds to step 320.

  And if it transfers to step 320, passenger detection ECU20 prohibits passenger detection determination. Thereafter, the occupant detection ECU 20 activates the seat heater 24 (step 330).

  In step 340, the operating time of the seat heater 24 is determined. For example, based on the timer map indicating the relationship between the atmospheric temperature data detected by the occupant detection ECU internal temperature sensor 28 and the operating time of the seat heater 24 until reaching the temperature at which the accuracy of the detection performance of the load sensor 22 can be expected. Thus, the operating time of the seat heater 24 is determined.

  In step 350, the seat heater 24 continues to operate until the operating time γ minutes calculated in step 340 is reached. When it becomes more than γ minutes, the occupant detection ECU 20 turns off the seat heater 24 (step 360) and permits the occupant detection determination (step 370).

  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, as an occupant detection sensor for detecting an occupant on a seat, a load sensor is exemplified in the description of the above-described embodiment, but an infrared sensor or a temperature sensor for detecting the occupant's body temperature, whether or not light is blocked. An occupant on the seat may be detected based on a detection result of an illuminance sensor or the like to be detected.
Further, not only the in-seat temperature sensor 26 but also the seat internal temperature may be detected by estimating the temperature from the value of the current flowing when the seat heater 24 is operated.

1 is a vehicle cross-sectional view showing a system in which an occupant detection device according to an embodiment of the present invention is used. It is a flowchart which shows operation | movement of the passenger | crew detection apparatus of a 1st Example. It is a flowchart which shows operation | movement of the passenger | crew detection apparatus of a 2nd Example. It is a flowchart which shows operation | movement of the passenger | crew detection apparatus of a 3rd Example.

Explanation of symbols

10 seat 12 airbag ECU
20 Occupant detection ECU
22 Load sensor 24 Seat heater 26 In-seat temperature sensor 28 Occupant detection ECU internal temperature sensor

Claims (5)

An occupant detection device having an occupant detection sensor for detecting an occupant on a seat,
A heater having a function of warming at least the occupant detection sensor;
An occupant detection device comprising: a heater control means for controlling the heater so that the temperature of the occupant detection sensor or its surroundings is equal to or higher than a predetermined temperature.   The occupant detection device according to claim 1, wherein occupant detection based on a detection result of the occupant detection sensor is prohibited when a temperature of the occupant detection sensor or its surroundings is lower than the predetermined temperature.   The occupant detection device according to claim 1 or 2, wherein the predetermined temperature is set based on a temperature region in which the detection performance of the occupant detection sensor is poor.   The occupant detection device according to any one of claims 1 to 3, wherein the occupant detection sensor detects a weight applied to the seat as the occupant.   The occupant detection device according to claim 1, wherein the heater control unit controls the heater so that a time determined according to a temperature when the heater starts operation is passed.

Images