JP2012011803A - Device for detecting posture of occupant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect and determine the sitting posture of an occupant in response to various occupants.SOLUTION: The device 100 for detecting the posture of an occupant includes: an electrostatic capacity sensor section 10; and a circuit section 20. The electrostatic sensor section has: a main detecting electrode 19 disposed in a cabin ceiling part 2; and auxiliary detecting electrodes 41-44 disposed in a seat front surface part 3, a side door 4, a headrest 5 and a backrest part 6. The main detecting electrode and the auxiliary detecting electrodes are respectively connected to an electrostatic capacity-detecting circuit 21 and a shield driving circuit 23 of the circuit section 20 through selector switches SW1, SW4-SW7. A CPU 29 compares a detecting signal from the main detecting electrode with a threshold value, and determines whether a detected part of an occupant exists within an appropriate detection range of the main detecting electrode or not. If the detected part of the occupant exists in the appropriate detection range, the CPU 29 determines the sitting posture of the occupant based on the detecting signal from the main detecting electrode; and if the detected part of the occupant does not exist in the appropriate detection range, the CPU 29 determines the sitting posture based on the detecting signal from at least the auxiliary detecting electrode.

Description

  The present invention relates to an occupant posture detection device that detects the posture of an occupant (human body) seated in a vehicle seat.

  With the recent improvement in performance of vehicles such as automobiles, for example, the deployment of airbags for protecting passengers seated in a seat at the time of a vehicle collision is being controlled based on the posture of the passenger (sitting posture). is there. For example, a head position detection system disclosed in the following Patent Document 1 is known as a device that detects the posture of such an occupant.

  In this head position detection system, an oscillation electrode that is electrically connected in high frequency with an occupant seated in a vehicle seat (seat) is arranged in the seat seat (seat), and oscillation occurs between the oscillation electrode and the metal frame. An oscillating unit for applying an output and a distance measuring sensor in which a receiving electrode is disposed in an insulating manner on the ceiling of the vehicle compartment so as to face the oscillating electrode.

  Further, the head position detection system includes a calibration sensor that performs measurement by separating a known reception electrode from a conductor surface that is electrically connected to an occupant, facing the conductor surface, and insulating the calibration receiving electrode. And a processing circuit that determines each distance in the receiving electrode and a characteristic curve related to the output voltage based on the measurement result of, and applies each output voltage value to the corresponding characteristic curve to obtain each distance. With such a configuration, the position of the head is detected by measuring the distance between the head of the passenger and the receiving electrode.

JP 2002-365011 A

  However, in the conventional head position detection system disclosed in Patent Document 1 described above, the distance between the receiving electrode disposed on the ceiling of the passenger compartment above the seat and the head of the passenger seated on the seat is measured. However, since the position of the occupant's head is detected based on the measurement result, the detection accuracy is inferior in order to detect a fine sitting posture corresponding to various occupants such as adults and children. There is a problem of end.

  An object of the present invention is to provide an occupant posture detection device capable of detecting and determining a seating posture of an occupant with high accuracy corresponding to various occupants in order to eliminate the above-described problems caused by the prior art. To do.

  In order to solve the above-described problems and achieve the object, an occupant posture detection device according to the present invention is seated on at least one main detection electrode provided on a ceiling of a passenger compartment above a vehicle seat and the seat. At least one auxiliary detection electrode provided in the circumferential direction of the occupant, and posture determination means for determining a seating posture of the occupant based on a detection signal indicating capacitance from the main detection electrode and the auxiliary detection electrode; It is provided with.

  The occupant posture detection device according to the present invention includes auxiliary detection electrodes provided in the circumferential direction of the occupant in addition to the main detection electrodes provided on the ceiling of the passenger compartment. Correspondingly, the seating posture of the occupant can be detected and determined with high accuracy.

  In the occupant posture detection device according to the present invention, the posture determination means compares the detection signal with a predetermined threshold value so that the detection signal from the main detection electrode indicates that the detected portion of the occupant is the main detection portion. When the detection electrode indicates that it is within the appropriate detection range, the seating posture of the occupant is determined based on the detection signal from the main detection electrode, and the detection signal from the main detection electrode is detected by the detected portion of the occupant Indicates that the seating posture of the occupant is determined based on at least a detection signal from the auxiliary detection electrode.

  Thus, even when there is an occupant outside the appropriate detection range of the main detection electrode and the seating posture of the occupant cannot be determined by the detection signal from the main detection electrode, the seating posture is based on at least the detection signal from the auxiliary detection electrode. Therefore, it is possible to detect and determine the sitting posture with high accuracy corresponding to various occupants.

  The auxiliary detection electrode may be disposed on at least one of a seat front portion located in front of the seat, a side door next to the seat, a headrest of the seat, and a backrest portion of the seat.

  The posture detection means indicates that the detection signal from the main detection electrode indicates that the detected part of the occupant is outside the appropriate detection range of the main detection electrode, and the auxiliary detection arranged in the front part of the seat When the detection signal from the electrode is equal to or greater than a predetermined threshold value, it can be determined that the occupant is bent toward the seat front side.

  The posture determination means indicates that the detection signal from the main detection electrode indicates that the detected portion of the occupant is outside the appropriate detection range of the main detection electrode, and the auxiliary detection electrode disposed on the side door When the detection signal from the vehicle is greater than or equal to a predetermined threshold value, it can be determined that the occupant is leaning toward the side door.

  The posture determination means is arranged on the headrest and the backrest when the detection signal from the main detection electrode indicates that the detected part of the occupant is outside the appropriate detection range of the main detection electrode. The height of the occupant can be determined using a detection signal from the auxiliary detection electrode.

  ADVANTAGE OF THE INVENTION According to this invention, the passenger | crew attitude | position detection apparatus which can detect and determine a passenger | crew's sitting posture with high precision corresponding to various passenger | crew can be provided.

It is a figure showing the whole crew posture detection device composition concerning a 1st embodiment of the present invention. It is a figure which shows the structure of each detection electrode of the passenger | crew attitude | position detection apparatus. It is a figure for demonstrating the relationship between an electrostatic capacitance and distance. It is a figure for demonstrating the detection range and suitable detection range of a detection electrode. It is a flowchart which shows the passenger | crew attitude | position detection processing procedure by the passenger | crew attitude | position detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the whole structure of the passenger | crew attitude | position detection apparatus which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the operation principle of the head position determination of the passenger | crew attitude | position detection apparatus. It is a figure for demonstrating the position determination operation | movement of the left-right direction of the head of the passenger | crew attitude | position detection apparatus. It is a figure for demonstrating the position determination operation | movement of the front-back direction of the head of the passenger | crew attitude | position detection apparatus. It is a figure which shows the structure of the passenger | crew attitude | position detection apparatus which concerns on the 3rd Embodiment of this invention.

  Hereinafter, a first embodiment of an occupant posture detection device according to the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, an occupant posture detection device 100 according to the first embodiment includes, for example, a static detection electrode 19 provided with at least one main detection electrode 19 provided in a passenger compartment ceiling 2 above a seat 40 of a vehicle 1. From the capacitance sensor unit 10, the auxiliary detection electrodes 41, 42, 43, and 44 provided in the circumferential direction of the occupant (human body) 48 seated on the seat 40, and the main detection electrode 19 and the auxiliary detection electrodes 41 to 44, respectively. And a circuit unit 20 that determines the seating posture of the occupant 48 seated on the seat 40 based on a detection signal indicating the electrostatic capacity of the vehicle.

  The main detection electrode 19 of the capacitance sensor unit 10 is arranged in a state having a detection surface substantially parallel to the horizontal direction inside the vehicle interior ceiling portion 2 or on the vehicle interior side surface. The electrostatic capacitance between the vehicle interior and the ceiling part 2 (specifically, the main detection electrode 19) is detected. More specifically, the main detection electrode 19 of the capacitance sensor unit 10 detects capacitance between the head portion 49 of the head 49 of the occupant 48.

  The auxiliary detection electrode 41 is arranged in a state having a detection surface substantially parallel to the vertical direction inside or on the front side of the seat front portion 3 located in front of the seat 40 of the vehicle 1. It is arranged in a state having a detection surface substantially parallel to the vertical direction inside the side door 4 next to the seat 40 or on the vehicle interior side.

  In addition, the auxiliary detection electrode 43 is disposed in the headrest 5 of the seat 40 or in a state having a detection surface substantially parallel to the surface thereof on the front surface side, and the auxiliary detection electrode 44 is provided inside or on the front surface of the backrest portion 6 of the seat 40. It is arranged with a detection surface substantially parallel to the surface on the side.

  Therefore, the auxiliary detection electrode 41 detects the electrostatic capacitance in a direction (horizontally toward the rear of the vehicle 1) from the seat front part 3 to the backrest part 6 of the seat 40, and the auxiliary detection electrode 42 is a side door. The electrostatic capacitance in the direction (horizontal direction from left to right or from right to left) of the vehicle 1 is detected from 4 to above the seating portion 7 in a substantially horizontal direction.

  Further, the auxiliary detection electrode 43 is a direction that substantially intersects the front surface of the headrest 5 from the headrest 5 of the seat 40 (ie, a direction that is substantially horizontal above the seating portion 7 when the seat 40 is in a normal state (that is, a vehicle 1)), and the auxiliary detection electrode 44 substantially intersects the front side surface of the backrest 6 from the backrest 6 of the seat 40 (when the seat 40 is in a normal state). Detects the electrostatic capacitance in a direction substantially horizontally above the seating portion 7 (also in the direction toward the front of the vehicle 1).

  The seat front portion 3 includes, for example, a steering wheel (handle) and an instrument panel when the seat 40 is a driver seat of the vehicle 1, and a dashboard and a dashboard panel when the seat 40 is a passenger seat. Including glove box. Moreover, when the seat 40 is a rear seat, the back side of the backrest portion 6 of the front seat is included. The auxiliary detection electrodes 41 to 44 arranged in this way can detect the circumferential capacitance of the occupant 48 seated on the seat 40.

  Here, in the capacitance sensor unit 10, for example, in order to promote modularization of components and the like, the main detection electrode 19 as described above is formed on one surface side of a substrate (not shown), and the vehicle interior ceiling unit 2 is formed. May be arranged. Further, the circuit unit 20 may be disposed after being mounted on the same surface side or the other surface side of the substrate. In addition, depending on the mode of arrangement, each part may be arranged separately, or only the main detection electrode 19 may be directly formed on the vehicle interior ceiling 2. Further, the auxiliary detection electrodes 41 to 44 may also be formed on the substrate as described above.

  When the capacitance sensor unit 10 or the like is formed on a substrate, for example, a flexible printed circuit (FPC), a rigid substrate, a rigid flexible substrate, or the like is used as the substrate. For example, when the substrate is made of FPC, the main detection electrode 19 and the auxiliary detection electrodes 41 to 44 are polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polyamide (PA), or glass epoxy resin. It is made of a conductive material such as copper, copper alloy or aluminum patterned on a base material made of an insulator.

  In addition, the main detection electrode 19 and the auxiliary detection electrodes 41 to 44 may be formed in a membrane circuit, or may be formed of other members such as a conductive adhesive material, a conductive film, or a general electric wire. Depending on the location, a transparent electrode may be used. In this case, the substrate may be formed of a transparent panel or film material, and the main detection electrode 19 and the auxiliary detection electrodes 41 to 44 may be configured with transparent electrodes.

  Here, for example, ITO (tin-doped indium oxide), PEDOT / PSS (polyethylene dioxythiophene / polystyrene sulfonic acid), or PEDOT / TsO (polyethylene dioxythiophene / toluene sulfonate) is used as the transparent electrode. Can do.

  The main detection electrode 19 configured in this way is connected to, for example, the capacitance detection circuit 21 of the circuit unit 20 via the changeover switch SW1, and can be connected to the shield drive circuit 23 via this changeover switch SW1. It is configured. Similarly, the auxiliary detection electrodes 41 to 44 are connected to the capacitance detection circuit 21 via the changeover switches SW4, SW5, SW6, and SW7, respectively, and to the shield drive circuit 23 via the changeover switches SW4 to SW7. It is configured to be connectable. Although illustration is omitted, the shield drive circuit 23 may be provided in the circuit unit 20.

  Further, as described above, it is sufficient that at least one auxiliary detection electrode 41 to 44 is provided in the circumferential direction of the occupant 48, and the arrangement mode thereof is, for example, the front, rear, left and right of the occupant 48 seated on the seat 40 as described above. It suffices if it is installed so as to constitute a range in which a capacitance for determining a difference in posture change or height can be appropriately detected.

  That is, the main detection electrode 19 detects the capacitance in the direction (vertical direction) toward the seat 40 (the seating portion 7 thereof), and the auxiliary detection electrodes 41 to 44 are circumferential directions (horizontal) surrounding the occupant 48 seated on the seat 40. Direction). As a result, the seating posture of the occupant 48 can be detected in detail and with high accuracy in the X, Y, and Z directions shown in FIG.

  On the other hand, the circuit unit 20 includes a capacitance detection circuit 21 that detects each capacitance value based on a detection signal indicating the capacitance detected by the main detection electrode 19 and the auxiliary detection electrodes 41 to 44, and An A / D converter 22 that converts an analog signal from the capacitance detection circuit 21 into a digital signal, and various operations of the occupant posture detection device 100 based on the information converted into a digital signal by the A / D converter 22 The CPU 29 controls control and arithmetic processing, and determines the seating posture of the occupant 48 and outputs information (posture information) on the determined seating posture to, for example, an ECU (electronic control unit) mounted on the vehicle 1. And is configured.

  The ECU functions to control the deployment of various airbags such as a driver airbag, a passenger airbag, and a side airbag mounted on the vehicle 1 (that is, control the airbag opening direction, expansion rate, etc.). And deployment of the airbag can be controlled with reference also to the posture information from the occupant posture detection device 100 of the first embodiment.

  Each change-over switch SW1, SW4-SW7 consists of units, such as a multiplexer, an analog switch, FET, or a relay, for example. Further, the circuit unit 20 includes a ROM as an information storage area (not shown), a RAM as a temporary calculation area of the CPU 29, and the CPU 29 outputs a switching control signal for switching operations of the selector switches SW1, SW4 to SW7. Control. Specifically, the occupant posture detection device 100 performs the following switching control.

  That is, for example, when the changeover switch SW1 is switched so that the main detection electrode 19 and the capacitance detection circuit 21 are connected by the changeover control signal from the CPU 29, the changeover switches SW4 to SW7 are set to the auxiliary detection electrodes 41 to 41. 44 are switched to be connected to the shield drive circuit 23, respectively.

  For example, when the changeover switch SW4 is switched so that the auxiliary detection electrode 41 and the capacitance detection circuit 21 are connected, the changeover switches SW1, SW5 to SW7 are the main detection electrode 19 and the auxiliary detection electrodes 42 to 44. Is switched to be connected to the shield drive circuit 23.

  Thus, when a certain detection electrode is switched by the changeover switch so as to be connected to the capacitance detection circuit 21, the other detection electrode is changed by the changeover switch so as to be connected to the shield drive circuit 23. Then, the CPU 29 selectively connects the main detection electrode 19 and the auxiliary detection electrodes 41 to 44 and the capacitance detection circuit 21 as described above (for example, when switched in order and connected). The seating posture of the occupant 48 is determined based on the detected capacitance values.

  The shield drive circuit 23 is configured to give a potential equivalent to the potential given by the capacitance detection circuit 21 to the connected detection electrode. As a result, it is possible to prevent electrostatic capacitance coupling between the main detection electrode 19 and the auxiliary detection electrodes 41 to 44, and to detect capacitance with high accuracy for each detection electrode.

  In addition, the shield drive circuit 23 may apply a potential generated through a single amplifier (buffer) with a higher impedance than the potential applied to the main detection electrode 19 and the auxiliary detection electrodes 41 to 44, for example. In addition, when the capacitance detection circuit 21 is a differential operation type, an equivalent potential may be applied by connecting a non-inverting input portion of an operational amplifier. By adopting the differential operation type, it is possible to cancel the temperature characteristics in the circuit while removing common mode noise. Since the differential operation type circuit configuration and operation principle are well-known techniques, description thereof is omitted here.

  As shown in FIG. 2, the main detection electrode 19 and the auxiliary detection electrodes 41 to 44 are each formed in a rectangular shape, for example, and each detection is performed on the back surface side (the side opposite to the detection range side where the detection surface is present). A shield part 17 that is electrically insulated from the electrode and suppresses detection of capacitance on the back side thereof, and a shield part 18 that provides the same effect around each detection electrode are formed. Also good.

  For example, the same potential as the main detection electrode 19 and the auxiliary detection electrodes 41 to 44 is applied to the shield portions 17 and 18. If such shield parts 17 and 18 are provided, the electrostatic capacity between the vehicle interior ceiling part 2 and the head 49, the seat front part 3, the side door 4, the headrest 5 and the backrest part 6 can be more accurately obtained. It is possible to detect the capacitance between the passenger 48 and the passenger 48.

  Since the occupant posture detection device 100 according to the first embodiment has a very large volume and dielectric constant compared to the main detection electrode 19 and the auxiliary detection electrodes 41 to 44, the occupant posture detection device 100 is almost grounded. The principle that can be regarded as (GND) is used. For this reason, the circuit part 20 employ | adopts the structure which can determine the seating attitude | position of the passenger | crew 48 using the electrostatic capacitance between each detection electrode and a ground (for example, passenger | crew 48).

  Therefore, according to the occupant posture detection device 100 having such a configuration, compared to a conventional device that requires transmission and reception of many signals in the system, such as the head position detection system described in the section of the related art. Thus, it is possible to construct a system capable of detecting a sitting posture with a very simple configuration and high accuracy. The specific operation of the occupant posture detection device 100 is, for example, as follows.

  First, when the operation is started, the CPU 29 of the circuit unit 20 connects the main detection electrode 19 to the capacitance detection circuit 21 by the changeover switch SW1, and the auxiliary detection electrodes 41 to 44 by the changeover switches SW4 to SW7. The change-over switches SW1, SW4 to SW7 are switched so as to be connected to the H.23.

  Here, the CPU 29 has, for example, a capacitance detected by the main detection electrode 19 of the capacitance sensor unit 10 equal to or higher than a predetermined threshold value (hereinafter simply referred to as “threshold value”). It is determined whether or not. Specifically, as shown in FIG. 3, the CPU 29, for example, when the capacitance value (V) from the main detection electrode 19 of the capacitance sensor unit 10 is equal to or greater than a threshold value (Th1). Then, it is determined that the distance d between the main detection electrode 19 and the head 49 of the occupant 48 is within the distance d1 (that is, within the appropriate detection range of the detectable range of the main detection electrode 19).

  As shown in FIG. 4, the appropriate detection range B of the main detection electrode 19 is a range in which the head 49 of the occupant 48 can be detected appropriately in the detectable range A of the main detection electrode 19. . Therefore, it can be said that the appropriate detection range B is a range of an area included in the range A that is narrower than the range A. The auxiliary detection electrodes 41 to 44 also have such a detectable range and an appropriate detection range, although illustration and description are omitted. Moreover, the to-be-detected site | part of the passenger | crew 48 means the site | part of the passenger | crew 48 nearest from the main detection electrode 19 (or auxiliary detection electrodes 41-44).

  In this case, the CPU 29 determines the seating posture of the occupant 48 based on only the detection signal from the main detection electrode 19 without using the detection signals from the auxiliary detection electrodes 41 to 44, for example. Thereby, the seating posture when the detected portion (here, the head 49) of the occupant 48 is within the appropriate detection range B of the main detection electrode 19 is an unnecessary (unnecessary) from the auxiliary detection electrodes 41 to 44. The determination can be made with the signal processing simplified as much as possible without using the detection signal.

  On the other hand, when the capacitance value (V) from the main detection electrode 19 of the capacitance sensor unit 10 is less than the threshold value (Th), it is between the main detection electrode 19 and the head 49 of the occupant 48. Is determined to be longer than the distance d1 (that is, outside the appropriate detection range B in the range A detectable by the main detection electrode 19). In such a case, in the CPU 29, the auxiliary detection electrodes 41 to 44 are sequentially connected to the electrostatic capacitance detection circuit 21 by the changeover switches SW4 to SW7, respectively, and the main detection electrode 19 is connected to the shield drive circuit 23 by the changeover switch SW1. In this manner, the selector switches SW1, SW4 to SW7 are switched.

  Similarly, it is determined whether or not the capacitance detected by the auxiliary detection electrodes 41 to 44 is equal to or greater than a threshold value, and the seating posture of the occupant 48 is determined based on the determination result. Further, even when it is determined that it is outside the appropriate detection range B of the main detection electrode 19, not only the capacitance value from the auxiliary detection electrodes 41 to 44 but also the capacitance value from the main detection electrode 19. Further, the seating posture of the occupant 48 may be determined in consideration.

  The occupant posture detection device 100 according to the first embodiment connects the main detection electrode 19 and the auxiliary detection electrodes 41 to 44 to one capacitance detection circuit 21 via the changeover switches SW1 and SW4 to SW7. The switching switches SW1, SW4 to SW7 are switched by the switching control by the CPU 29, and the seating posture of the occupant 48 is determined using the capacitance values detected by the main detection electrode 19 and the auxiliary detection electrodes 41 to 44. However, for example, the capacitance detection circuit 21 may be provided for the main detection electrode 19 and the auxiliary detection electrodes 41 to 44, respectively. However, in this case, it is necessary to synchronize each electrostatic capacitance detection circuit because the electric potential of the other detection electrode is affected when the electrostatic capacitance is detected (measured) by one detection electrode. There is.

  Here, the capacitance detection circuit 21 changes the duty ratio according to the capacitance between the main detection electrode 19 and the auxiliary detection electrodes 41 to 44 and the head 49 of the occupant 48 or the trunk of the occupant 48. A pulse signal is generated and smoothed to output a detection signal. That is, the capacitance detection circuit 21 has a CV conversion function for converting capacitance (Capacitance) into voltage (Voltage). For example, a circuit for measuring a known CR charge / discharge time, a charged charge is known. It is possible to configure using a circuit for transferring to a capacitor, a circuit for measuring impedance, a circuit for configuring an oscillation circuit and measuring an oscillation frequency, and the like.

  The occupant posture detection device 100 configured as described above determines the seating posture of the occupant 48 in detail as follows, for example. That is, as described above, when it is determined that it is within the appropriate detection range B of the main detection electrode 19, the position of the head 49 of the occupant 48 is the normal posture (that is, the normal basic posture that matches the shape of the seat 40). It is determined that an adult (a person with a certain height or more) is sitting normally.

  On the other hand, when it is determined that it is outside the appropriate detection range B of the main detection electrode 19, the position of the head 49 of the occupant 48 when the detection signal from the auxiliary detection electrode 41 of the seat front portion 3 is equal to or greater than a threshold value. Is an attitude in the vicinity of the seat front part 3 (an attitude bent forward), it is determined that an adult or a child is bent (including a case where the child is riding forward).

  When it is determined that the main detection electrode 19 is outside the appropriate detection range B, when the detection signal from the auxiliary detection electrode 42 of the side door 4 is equal to or greater than the threshold value, the trunk of the occupant 48 is moved to the side door 4. It is determined that an adult or a child is leaning on the side door 4 as a posture in the vicinity of (a posture leaning to the side).

  Further, when it is determined that the main detection electrode 19 is outside the appropriate detection range B, for example, the height of the occupant 48 is determined using detection signals from the auxiliary detection electrodes 43 and 44 of the headrest 5 and the backrest 6. Anyway. The determination of the height of the occupant 48 is, for example, a value obtained by dividing the capacitance value indicated by the detection signal from the auxiliary detection electrode 43 by the capacitance value indicated by the detection signal from the auxiliary detection electrode 44 is less than the threshold value. In this case, it is determined that the child is sitting in a normal posture, assuming that the person is less than a certain height.

  For example, if the value obtained by dividing the capacitance value indicated by the detection signal from the auxiliary detection electrode 43 by the capacitance value indicated by the detection signal from the auxiliary detection electrode 44 is equal to or greater than the threshold value, the height is somewhat Assuming that the person is the above person, it is determined that the adult is sitting in a normal posture. And such determination may be performed independently, respectively, and since it can also be performed using combining the detection signal from these auxiliary detection electrodes 41-44, the passenger | crew attitude | position detection apparatus 100 of 1st Embodiment. Can detect the sitting posture of the occupant 48 in more detail and with high accuracy.

  That is, for example, outside the appropriate detection range B of the main detection electrode 19, the detection signal from the auxiliary detection electrode 41 is greater than or equal to the threshold value, and the detection signal from the auxiliary detection electrode 42 is greater than or equal to the threshold value Th1. At this time, it is determined that the adult is bent from these combinations (or leaning on the side door 4 instead of or in addition to this).

  Further, the threshold is outside the appropriate detection range B of the main detection electrode 19, the detection signal from the auxiliary detection electrode 41 is equal to or greater than the threshold value, and the detection signal from the auxiliary detection electrode 42 is smaller than the threshold value Th1. When the value is equal to or less than Th2, it is determined that the child is moving forward from these combinations. When the detection signal from the auxiliary detection electrode 42 is smaller than the threshold value Th1 and larger than the threshold value Th2 under such conditions, it is determined that the adult is bent.

  Further, outside the appropriate detection range B of the main detection electrode 19, the detection signal from the auxiliary detection electrode 42 is equal to or less than the threshold value Th2, and the capacitance value indicated by the detection signal from the auxiliary detection electrode 43 is assisted. When the value divided by the capacitance value indicated by the detection signal from the detection electrode 44 is less than the threshold value, it is determined from these combinations that the child is sleeping with the backrest 6 lying down, and the divided value described above. Is equal to or greater than the threshold value, it is determined that the adult is lying on the backrest 6 while sleeping.

  The determination of the height of the occupant 48 using the capacitance value indicated by the detection signals from the auxiliary detection electrodes 43 and 44 can be performed by various calculations in addition to the division described above. Moreover, since the determination conditions listed above are merely examples, the occupant posture detection device 100 of the first embodiment is not limited to this. The occupant posture detection process performed by the occupant posture detection apparatus 100 will be briefly described as follows. In the following description, the same reference numerals are given to the same portions as those already described, and description thereof is omitted.

  As shown in FIG. 5, first, the CPU 29 of the circuit unit 20 switches the selector switches SW1, SW4 to SW7, whereby the electrostatic capacitance is detected by the main detection electrode 19 by the electrostatic capacitance detection circuit 21 (step S101). ).

  Next, the CPU 29 determines whether or not the capacitance value indicated by the detection signal from the capacitance detection circuit 21 is greater than or equal to a threshold value (step S102). If it is determined that the capacitance value is greater than or equal to the threshold value (Y in step S102), the posture determination as described above is performed (step S103), and posture information based on the determination result is output (step S104). Then, a series of occupant posture detection processing according to this flowchart is completed.

  On the other hand, when it is determined that the capacitance value is less than the threshold value (N in step S102), the changeover switches SW1, SW4 to SW7 are switched, and the capacitance detection circuit 21 uses the auxiliary detection electrodes 41 to 44. Is detected (step S105), the process proceeds to step S103, the posture determination as described above is performed (step S103), and the subsequent processing is executed.

  The circuit unit 20 stores in advance the capacitance values based on the capacitance when the occupant 48 is not seated in the seat 40 in the above-described ROM, RAM, etc., and stores them in these when the occupant 48 is seated. The increase amount from the electrostatic capacitance value thus detected may be detected and used for posture determination.

  Thus, according to the occupant posture detection device 100 of the first embodiment, the seating posture of the occupant 48 seated on the seat 40 can be detected and determined in detail and with high accuracy. Thereby, the deployment control of various airbags mounted on the vehicle 1 can be finely performed in accordance with the seating posture of the occupant 48. Next, a second embodiment of the occupant posture detection device according to the present invention will be described in detail.

  As shown in FIG. 6, an occupant posture detection device 100A according to the second embodiment includes the occupant posture detection device 100 according to the first embodiment, the configuration of the capacitance sensor unit 10, and the configuration of the changeover switch. Is different. That is, the capacitance sensor unit 10 of the occupant posture detection device 100A is positioned on the plane of the head of the occupant 48 seated on the seat 40 in the passenger compartment ceiling 2 above the seat 40 of the vehicle 1, for example. 3 detection electrodes (first main detection electrode 11, second main detection electrode 12, and third main detection electrode 13) arranged so as to be detectable.

  In the first to third main detection electrodes 11 to 13, for example, the first main detection electrode 11 is a vertex on the front side of the vehicle 1, and the second and third main detection electrodes 12 and 13 are left and right of the vehicle 1 on the seat 40. The vehicle interior ceiling is arranged so as to form a triangular plane (for example, an isosceles triangle having the first main detection electrode 11 at the front vertex) when the main detection electrodes 11 to 13 are linearly connected to each other. It is arrange | positioned in the inside of the part 2, or the vehicle interior side surface.

  The first main detection electrode 11 is disposed so as to be connectable to the capacitance detection circuit 21 and the shield drive circuit 23 via the changeover switch SW1. Further, the second main detection electrode 12 is arranged to be connectable to the capacitance detection circuit 21 and the shield drive circuit 23 via the changeover switch SW2 and the third main detection electrode 13 via the changeover switch SW3. Has been.

  And the electrostatic capacitance sensor part 10 comprised in this way detects the electrostatic capacitance between the head 49 of the passenger | crew 48 and the vehicle interior ceiling part 2 (specifically each main detection electrodes 11-13). To do. Based on the detection signal indicating the capacitance thus detected, the CPU 29 of the circuit unit 20 has the head 49 of the occupant 48 within the appropriate detection range B of the main detection electrodes 11 to 13 (as described above). Or not).

  In this case, the determination as to whether or not the value is within the appropriate detection range B is performed by comparing the total capacitance value or average capacitance value from the main detection electrodes 11 to 13 with a threshold value, for example. . Here, since the operation when it is determined that it is outside the appropriate detection range B is the same as the operation described in the first embodiment, it is mainly within the appropriate detection range B here. The operation and the like when it is determined will be described.

  The occupant posture detection device 100A according to the second embodiment determines the position of the head 49 with high accuracy when the head 49 of the occupant 48 is within the appropriate detection range B of the main detection electrodes 11-13. Is configured to be possible. FIG. 7 is a diagram for explaining the operation principle of the head position determination of the occupant posture detection device 100A. (1), (2), and (3) of the graph in FIG. -Corresponds to the third main detection electrodes 11-13.

  As shown in FIG. 7A, for example, when the occupant 48 is seated near the front right side of the vehicle 1 with respect to the seat 40, the detected capacitance of (1) of the first main detection electrode 11 is detected. The value (hereinafter referred to as “detection value”) ΔC is larger than the detection value ΔC of (2) of the second main detection electrode 12 and the detection value ΔC of (3) of the third main detection electrode 13. Therefore, it can be seen that the position of the head 49 of the occupant 48 (for example, the top of the head, the same applies hereinafter) is near the lower portion of the first main detection electrode 11 (that is, the front side of the seat 40). Here, the detection value ΔC indicates, for example, the ratio of the detection value to the total detection value.

  Further, when the detection value ΔC of (2) of the second main detection electrode 12 and the detection value ΔC of (3) of the third main detection electrode 13 are compared, the detection value ΔC of (2) of the second main detection electrode 12. Is bigger. For this reason, it can be seen that the position of the head 49 of the occupant 48 is close to the lower vicinity (that is, the right side) of the second main detection electrode 12. That is, by comparing the detection values ΔC of the first to third main detection electrodes 11 to 13 in this way, in this case, the seating posture of the occupant 48 is such that the head 49 is positioned in front of the right side of the seat 40. It turns out that it is.

  On the other hand, as shown in FIG. 7B, for example, when the occupant 48 leans on the seat 40 in a normal state and sits in the center (sits in the normal posture), the second main detection electrode The detection value ΔC of 12 (2) and the third main detection electrode 13 (3) is larger than the detection value ΔC of the first main detection electrode 11 (1). For this reason, it can be seen that the position of the head 49 of the occupant 48 is close to the lower side of the second main detection electrode 12 and the third main detection electrode 13 (that is, the rear side of the seat 40).

  Further, when the detection value ΔC of (2) of the second main detection electrode 12 and the detection value ΔC of (3) of the third main detection electrode 13 are compared, these detection values ΔC are substantially equal. Therefore, it can be seen that the position of the head 49 of the occupant 48 is below the intermediate point between the second and third main detection electrodes 12 and 13 (that is, leans on the seat 40 and sits at the center position). .

  Thus, since the distance d from each main detection electrode 11-13 to the head 49 of the passenger | crew 48 can be calculated | required using each detected value (DELTA) C, the well-known triangulation method etc. of the head 49 are used. The position can be calculated. However, the relationship between the detected value ΔC and the distance d of the head 49 depends on the size of the head 49 of the occupant 48, the distance to the vehicle interior ceiling 2, and the like. In the occupant posture detection device 100A, in addition to the triangulation method described above, the following processing is performed to accurately calculate the position of the head 49.

  That is, the occupant posture detection device 100A can perform the following arithmetic processing in the circuit unit 20 so that the position of the head 49 can be accurately detected even if the size of the head 49 changes, for example. It is carried out. First, the front-rear position of the head 49 obtained by the above-described operation is stored as a parameter in storage means such as a RAM or ROM (not shown) provided in the circuit unit 20. The detection value ΔC is a correction value = detection value of the second main detection electrode 12 / (detection value of the second main detection electrode 12 + third main detection electrode 13) for simplification of processing and accurate position detection. This is used for the correction calculation processing using the equation (detected value).

  For example, as shown in FIG. 8A, when the head 49 of the occupant 48 seated on the seat 40 swings in the left-right direction (for example, the X direction), the left / right direction (X direction) of the head 49 of the occupant 48 And the correction value (normalized detection value (left and right)) calculated based on the detection value ΔC of the second and third main detection electrodes 12 and 13 as shown in the graph of FIG. In addition, even if there is a deviation in the detected value due to a difference in position in the front-rear direction, it is approximately expressed.

  As shown in FIGS. 7 (a) and 7 (b), when the main detection electrodes 11 to 13 are linearly connected, each is formed into an isosceles triangle having the first main detection electrode 11 as a vertex on the front side. In the occupant posture detection device 100A in which the main detection electrodes 11 to 13 are arranged, as shown in FIG. 8B, the above-described normalized detection values (left and right) depend on the position of the head 49 in the front-rear direction. There is little influence.

  Next, information on the position in the left-right direction determined in this way is stored as a parameter as described above, and correction value = (detection value of main detection electrode 11 / {main detection electrode 11) using detection value ΔC. 11 correction value + (detection value of main detection electrode 12 + detection value of main detection electrode 13) / 2}).

  For example, as shown in FIG. 9A, when the head 49 of the occupant 48 seated on the seat 40 swings in the front-rear direction (for example, the Y direction), the front-rear direction (Y direction) of the head 49 of the occupant 48 And the correction value (standardized detection value (front and back)) calculated based on the detection value ΔC of each main detection electrode 11 to 13 is represented as a graph shown in FIG. 9B. .

  As shown in FIGS. 7 (a) and 7 (b), when the main detection electrodes 11 to 13 are linearly connected, each is formed into an isosceles triangle having the first main detection electrode 11 as a vertex on the front side. In the occupant posture detection device 100A in which the main detection electrodes 11 to 13 are arranged, as shown in FIG. 9B, the above-described normalized detection values (front and back) are different in the left and right position of the head 49 ( For example, right, center, left, etc.).

  However, the position in the front-rear direction of the head 49 of the occupant 48 is accurately determined by determining the position in the left-right direction based on the result described with reference to FIG. be able to. It should be noted that, instead of the triangulation method described with reference to FIG. 7, the correction calculation process based on the above-described theoretical formula is adopted as the main process for detecting the head 49 (the top of the head), and the head of the head 49 is directly detected. You may comprise so that a position may be detected. In this way, the top of the head closer to the “point” than the head 49 can be directly detected, and the position can be obtained more accurately while reducing processing.

  In addition, a metal member is often used for a frame or the like in the interior ceiling 2 of the vehicle 1 or in the seat 40, and each main detection electrode is moved when the occupant 48 changes posture by moving the seat 40. The positional relationship between the occupants 48 and 11 to 13 and 19 and the auxiliary detection electrodes 41 and 42 and the like changes, and the capacitance value due to such a change in the external environment may be detected, leading to a malfunction.

  Therefore, in order not to be affected as much as possible by such changes in the external environment, although not shown in the drawing, together with the shield portions 17 and 18 described above, an auxiliary electrode (shield electrode) for suppressing the capacitance change. ) May be provided in the vicinity of the main detection electrodes 11 to 13, 19 and the auxiliary detection electrodes 41 and 42.

  In this case, it is only necessary that each shield electrode has a potential equal to that of each of the main detection electrodes 11 to 13 and 19 and the auxiliary detection electrodes 41 and 42. As in the case of the shield drive circuit 23, the equivalent potential is, for example, an amplifier (buffer) having a high input impedance from the potential applied to each of the main detection electrodes 11 to 13, 19 and the auxiliary detection electrodes 41, 42, etc., with a high input impedance. Alternatively, in the case of the differential operation type capacitance detection circuit 21, the non-inverting input portion of the operational amplifier may be connected to the shield electrode. Next, a third embodiment of an occupant posture detection device according to the present invention will be described in detail.

  As shown in FIG. 10, here, when the right first main detection electrode 11 a and the left first main detection electrode 11 b are provided and the main detection electrodes 11 a, 11 b, 12, and 13 are linearly connected, the vehicle 1 The points placed on the passenger compartment ceiling portion 2 in a rectangular plane shape that forms sides in the front-rear direction and the left-right direction are the passenger posture detection devices 100, 100A according to the first and second embodiments described above. It is different.

  In this way, the position of the head 49 of the occupant 48 seated on the seat 40 can be determined with higher accuracy. Although the number of the main detection electrodes is four here, even if the number of the main detection electrodes is five or more, for example, the position detection accuracy can be improved to some extent in terms of cost. It is valid. Moreover, the arrangement | positioning aspect mainly demonstrated using FIGS. 7-9 can also be changed, for example so that the 1st main detection electrode 11 may become an isosceles triangle so that it may become one vertex of the back side. .

  As described above, the occupant posture detection device according to the above-described embodiment includes the capacitance sensor unit 10 including the main detection electrodes 11 to 13 and 19 and the auxiliary detection electrode 41 disposed in the circumferential direction of the occupant 48. With the very simple and inexpensive configuration of .about.44 and the circuit unit 20, the seating posture of the occupant 48 seated on the seat 40 can be detected and determined in detail and with high accuracy.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Car interior ceiling part 3 Seat front part 4 Side door 5 Headrest 6 Backrest part 7 Seating part 10 Capacitance sensor part 11 1st main detection electrode 12 2nd main detection electrode 13 3rd main detection electrode 19 Main detection electrode 20 Circuit Unit 21 Capacitance Detection Circuit 22 A / D Converter 23 Shield Drive Circuit 29 CPU
40 seats 41 to 44 auxiliary detection electrodes 48 occupant 49 head 100 occupant posture detection device 100A occupant posture detection device

Claims (6)

At least one main detection electrode provided on the ceiling of the passenger compartment above the seat of the vehicle;
At least one auxiliary detection electrode provided in the circumferential direction of an occupant seated in the seat;
An occupant posture detection device comprising: posture determination means for determining a seating posture of the occupant based on a detection signal indicating capacitance from the main detection electrode and the auxiliary detection electrode. The posture determination means compares the detection signal with a predetermined threshold value,
When the detection signal from the main detection electrode indicates that the detected portion of the occupant is within the appropriate detection range of the main detection electrode, the seating posture of the occupant is determined based on the detection signal from the main detection electrode. Judgment,
When the detection signal from the main detection electrode indicates that the detected portion of the occupant is outside the appropriate detection range of the main detection electrode, the seating posture of the occupant is based on at least the detection signal from the auxiliary detection electrode The occupant posture detection device according to claim 1, wherein: The auxiliary detection electrode is disposed on at least one of a seat front portion located in front of the seat, a side door next to the seat, a headrest of the seat, and a backrest portion of the seat. The occupant posture detection device according to claim 1 or 2. The posture detection means indicates that the detection signal from the main detection electrode indicates that the detected part of the occupant is outside the appropriate detection range of the main detection electrode, and the auxiliary detection arranged in the front part of the seat The occupant posture detection device according to claim 3, wherein when the detection signal from the electrode is equal to or greater than a predetermined threshold value, it is determined that the occupant is bent toward the seat front side. The posture determination means indicates that the detection signal from the main detection electrode indicates that the detected portion of the occupant is outside the appropriate detection range of the main detection electrode, and the auxiliary detection electrode disposed on the side door 5. The occupant posture detection device according to claim 3, wherein when the detection signal from the vehicle is greater than or equal to a predetermined threshold value, it is determined that the occupant is leaning toward the side door. The posture determination means is arranged on the headrest and the backrest when the detection signal from the main detection electrode indicates that the detected part of the occupant is outside the appropriate detection range of the main detection electrode. The occupant posture detection device according to any one of claims 3 to 5, wherein a height of the occupant is determined using a detection signal from the auxiliary detection electrode.

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