JP6028623B2 - Seat occupant determination device - Google Patents

Description

  The present invention relates to a seat occupant determination device that determines whether or not an occupant is seated on a vehicle seat based on a load value detected by a load detection device, and more particularly to occupant recognition by accurately determining occupant getting off. The present invention relates to a seat occupant determination device capable of accurately shifting from a mode to a no-sitting recognition mode.

  In a vehicle seat of an automobile, when an occupant is seated on the seat, an airbag is deployed at the time of an accident. For this purpose, a load detection device that detects the occupant's load is provided. . Then, when the load detected by the load detection device exceeds a predetermined threshold, it is determined that the passenger is seated, and when the load is equal to or less than the threshold, it is determined that the seat is not seated. It is supposed to be.

  Patent Document 1 describes an example of an occupant detection device that detects a load acting on a seat to determine the presence or absence of an occupant. In the occupant detection device described in Patent Document 1, load sensors are installed only at two front and rear positions of the four seat mounting portions, and the presence or absence of the occupant is determined from the sum of the two obtained load values. Yes.

  According to the occupant detection device described above, the load sensor is mounted at two places on the left or right side of the seat mounting portion so that the number of load sensors can be minimized and the cost and weight of the device can be reduced. However, the presence or absence of a passenger can be determined.

JP-A-9-207638

  However, in the method of installing load sensors at two positions on the left or right side of the seat mounting portion, the load value detected by the load sensor fluctuates with the turning of the vehicle, and there is a risk of erroneous determination. . For example, when load sensors are installed at two front and rear positions on the passenger seat side of a left-hand drive vehicle, the load value detected by the load sensor is caused by the centrifugal force acting on the seat as the vehicle turns left. Decrease. For this reason, it becomes difficult to distinguish whether the load value detected by the load detection device is due to the passenger getting off or the vehicle turning, and depending on the behavior of the vehicle, the airbag display lamp May continue to light.

  The present invention has been made in view of the above problems, and provides a seat occupant determination device that can accurately determine occupant disembarkation and accurately perform a transition from the occupant seating recognition mode to the non-sitting recognition mode. It is the purpose.

  In order to solve the above-described problem, a feature of the invention according to claim 1 is that a seat belt wearing detection unit that detects whether the seat belt is in a wearing state or a non-wearing state, and a lower side of the vehicle seat The seat belt is changed from the mounted state to the non-mounted state by the load detection device including two load sensors that are disposed on the front and rear sides of the left and right sides to detect the load acting on the vehicle seat, and the seat belt mounting detection unit. In the state change determination unit for determining this, and in the occupant seating recognition mode, the variation range of the load detected by the load detection device in the state where the seat belt non-mounting state is detected by the seat belt mounting detection unit is If it is within the threshold value of 1, the first judgment is made to determine that no occupant is seated on the vehicle seat by getting off the occupant and shift to the no-sitting recognition mode. In the processing unit and the occupant seating recognition mode, when the state change determination unit detects that the seat belt has changed from the mounted state to the non-mounted state, the load detection device detects for a predetermined time. If the fluctuation range of the applied load is within a second threshold value that is larger than the first threshold value, it is determined that no occupant is seated on the vehicle seat by getting off the occupant, and a transition to the no-sitting recognition mode is made. 2 is a seat occupant determination device including a determination processing unit.

  The invention according to claim 2 is characterized in that, after the seat belt is changed from the mounted state to the non-mounted state, the determination is made by the second determination processing unit for a predetermined time, and after the predetermined time has elapsed, the first belt The seat occupant determination device according to claim 1, wherein the determination is made by a determination processing unit.

  According to the first aspect of the present invention, it is possible to accurately determine whether or not the occupant gets out of the occupant from the occupant seating recognition mode within a certain period of time after detecting that the seat belt has changed from the mounted state to the non-mounted state. The transition to the non-sitting recognition mode can be performed with high accuracy. In other words, when the seat belt changes from the wearing state to the non-wearing state, there is a high probability that the occupant will get off within a certain time. Regardless of the fluctuation, it is possible to determine the passenger getting off at an early stage, and it is possible to prevent the airbag display lamp from being lit continuously despite the passenger getting off.

  According to the second aspect of the present invention, after the seat belt is changed from the mounted state to the non-mounted state, the determination is made by the second determination processing unit for a predetermined time, and after the predetermined time has elapsed, the first determination processing unit. Therefore, after the seat belt changes from the mounted state to the non-mounted state, it is possible to accurately determine whether the occupant is getting off without losing sight of the passenger getting off for a predetermined time. After the elapse of time, the load fluctuation width is reduced, so that it is possible to avoid confusion with the load fluctuation caused by turning of the vehicle.

It is a perspective view of a vehicle seat provided with a seat occupant determination device showing an embodiment of the invention. It is the figure which looked at the vehicle seat from the upper surface. It is a block diagram of a seat occupant determination device. It is a figure which shows the transition state of a seat occupant determination apparatus. It is a graph which shows the experimental data of a load fluctuation. It is a figure which shows the flowchart of a seat occupant determination apparatus.

  Hereinafter, an embodiment of a vehicle seat 11 provided with a seat occupant determination device 10 according to the present invention will be described with reference to the drawings. In addition, the directions of “front and rear, left and right, and up and down” used in this specification are described with reference to each direction of the vehicle viewed from the occupant seated on the vehicle seat 11. In the present embodiment, the vehicle is a left-hand drive vehicle, and the presence / absence of a passenger seated in the passenger seat is determined.

  As shown in FIG. 1, a seat cushion 11a as a seating surface on which an occupant is seated and a backrest that is attached to the rear end portion of the seat cushion 11a so as to be pivotable in the front-rear direction. The seat back 11b is provided. Further, the vehicle seat 11 is restrained when the occupant seated on the seat cushion 11a or a load detection device 12 (see FIGS. 2 and 3) for detecting the load of the load and the occupant seated on the vehicle seat 11 are attached. A seat belt 13 that is opened when worn, a buckle switch 14 that detects whether the seat belt 13 is worn or not, and a controller 15 are provided.

  The vehicle seat 11 is supported on the vehicle floor via a pair of left and right upper rails 17 of a seat slide device 16 that supports the vehicle seat 11 so that the position of the vehicle seat 11 can be adjusted in the longitudinal direction of the vehicle. On the pair of left and right upper rails 17, as shown in FIG. 2, four support legs 17 a, 17 b, 17 c, and 17 d that support the seat cushion 11 a of the vehicle seat 11 are separated from each other in the left-right direction and the front-rear direction of the vehicle. The four corners are arranged.

  The load detection device 12 is constituted by two load sensors 12a and 12b, and the load sensors 12a and 12b are strain gauge type sensors incorporating an amplifier. The two load sensors 12a and 12b are interposed between the seat cushion 11a and the upper rail 17 at two positions on the left and right sides (inner side) of the four support leg portions 17a to 17d described above. The load of an occupant seated on the 11 seat cushions 11a can be detected by the two load sensors 12a and 12b.

  As shown in FIG. 1, the seat belt 13 is provided with a tongue plate 20 in the middle thereof, and a buckle 21 detachably attached to the tongue plate 20 is provided at a side portion of the seat cushion 11a. The buckle 21 has a built-in buckle switch 14 that constitutes a seat belt wearing detection unit. When the tongue plate 20 is engaged with the buckle 21, the buckle switch 14 is turned on by assuming that the seat belt 13 is in the worn state. A signal is output. Further, when the tongue plate 20 is not engaged with the buckle 21, the buckle switch 14 outputs an OFF signal on the assumption that the seat belt 13 is not attached.

  FIG. 3 is a block diagram of the seat occupant determination device 10. A controller (ECU) 15 as a control device includes a CPU 33, a RAM 34, a ROM 35, and an interface 36, and a seat occupant determination program is stored in the ROM 35. Stored. In the RAM 34, the load signals detected by the two load sensors 12a and 12b, the ON / OFF signal of the buckle switch 14 of the seat belt 13, and the ON / OFF detection switch 30 for detecting the opening / closing of the door on the passenger seat side are turned ON. A / OFF signal is input via the interface 36. Further, an airbag display lamp 31 that displays that the airbag (not shown) is in an operable state is connected to the CPU 33 via an interface 36.

  The CPU 33 adds the load signals from the two load sensors 12a and 12b transmitted to the RAM 34, thereby detecting the weight of the passenger seated on the vehicle seat 11 and the weight of the load placed on the vehicle seat 11. . For example, when an occupant or the like is seated in a normal posture on the vehicle seat 11, substantially equal loads are applied to the two load sensors 12a and 12b disposed at the two front and rear sides of the seat cushion 11a. Be loaded.

  Accordingly, the load signals detected by the two load sensors 12a and 12b are added by the CPU 33, so that the weight of the passenger seated on the vehicle seat 11 and the weight of the luggage can be detected. Note that the outputs of the load sensors 12a and 12b are zero-calibrated when the vehicle is on a flat ground and nothing is seated or placed on the seat cushion 11a.

  Further, the RAM 34 stores a storage area A1 for storing a “no-sitting recognition mode” M1 for recognizing a non-sitting state in which no occupant is seated on the vehicle seat 11; A storage area A2 for storing “M2” and a storage area A3 for storing a “package recognition mode” M3 for recognizing the loading state of the package are provided. When the “seating absence recognition mode” M1 and the “luggage recognition mode” M3 are stored, the airbag display lamp 31 is turned off. When the “occupant seating recognition mode” M2 is stored, the airbag display lamp 31 is displayed. Illuminated.

  As shown in FIG. 4, the controller 15 performs a first transition process 37 and a second transition process 38. The first transition process 37 is performed under the condition that in the “no-sitting recognition mode” M1, the load detection device 12 continuously detects a load larger than the first load W1 and smaller than the second load W2 for a preset time t1. To the “cargo recognition mode” M3, and in the “cargo recognition mode” M3, the load detection device 12 continues the load slightly smaller than the first load W1 and smaller than the third load W3 for a preset time t2. The process proceeds to the “no seating recognition mode” M1 on the condition that it has been detected.

  Further, the second transition process 38 performs the “occupant seat recognition” on condition that the load detection device 12 continuously detects a load larger than the second load W2 for a preset time t1 in the “no seating recognition mode” M1. The mode is shifted to “M2” and the “occupant seating recognition mode” M2 is performed under the condition that the load detection device 12 continuously detects a load smaller than the third load W3 for a preset time t2. “Transition to M1.

  In the present embodiment, the basis for determining the “occupant seating recognition mode” M2 as the case where the load detection device 12 detects a load greater than or equal to the second load W2 is that the seat belt 13 is mounted. This is because even when a 6-year-old or older child or a relatively small adult woman who needs a seat sits shallowly on the front portion of the seat cushion 11a, the passenger seating can be detected.

  By the way, in this Embodiment, since the load sensors 12a and 12b which comprise the load detection apparatus 12 are arrange | positioned only before and behind one side (inner side) of the vehicle seat 11, the load detected by the load detection apparatus 12 The value fluctuates depending on whether the occupant is seated on the vehicle seat 11 or separated from the vehicle seat 11 in order to get off the vehicle seat 11, and also varies depending on the left turn or right turn when the vehicle is traveling.

  That is, when the vehicle turns left, the vehicle seat 11 on the passenger seat side (right side of the vehicle) and the occupant seated on the vehicle seat are swung to the right side by centrifugal force, so the output of the load detection device 12 is small. Become. On the contrary, when the vehicle travels to the right, the output of the load detection device 12 increases.

  In this case, if the occupant seated on the vehicle seat 11 is wearing the seat belt 13, the “occupant seating recognition mode” M2 can be determined regardless of the decrease in the load detected by the load detection device 12, and “no seating” There is no transition to the “recognition mode” M1. However, in the state where the seat belt 13 is not attached, just because the output of the load detection device 12 is smaller than a certain threshold value, it cannot be determined as the “non-sitting recognition mode” M1, and the decrease in the load turns to the left. It is necessary to determine whether it is due to traveling or due to passengers getting off.

  Whether the load decreases due to turning or the load decreases due to the passenger getting off can be determined by looking at the fluctuation range of the load. For example, during a left turn, the output of the load detection device 12 is greatly reduced, but the output of the load detection device 12 is not stable. This is because it is difficult to keep the steering angle or the vehicle speed constant during turning, and the load fluctuates due to road surface unevenness.

  On the other hand, when an occupant seated in the passenger seat gets out of the vehicle, the vehicle is naturally stopped, so that not only the output of the load detection device 12 is greatly reduced but also the load detection device 12 The output will also be stable.

  According to experiments by the present inventors, a threshold value α (for example, about ± 0.2 kg) of a certain load fluctuation range is set, and it is checked whether or not the output of the load detection device 12 is within the load fluctuation range α. Thus, it was found that it was possible to distinguish between getting off the passenger and turning the vehicle. That is, when the load fluctuation range continues for a predetermined time within the threshold value α, it can be determined that the passenger is getting off, and when the load fluctuation range is outside the threshold value α, it can be determined that the vehicle is turning. Since the load fluctuation due to the influence of electrical noise and the load fluctuation due to the influence of idle vibration occur while the vehicle is stopped, the load fluctuation width is set so as to allow these fluctuations.

  By the way, after the occupant changes from the state of wearing the seat belt 13 to the non-mounted state, the occupant has a high probability of getting off for a predetermined time tz (for example, several tens of seconds). Unlikely. Therefore, after the seat belt 13 has changed from the wearing state to the non-wearing state, it is effective to set a wide load stabilizing width so that the vehicle can be accurately determined for a predetermined time tz.

  That is, by setting a large load fluctuation range to allow the vehicle seat 11 to vibrate even when the vehicle seat 11 vibrates due to closing of the door when getting off or contact of the passenger to the vehicle seat 11 when getting off, Can be determined early. As a result, the transition from the “occupant seating recognition mode” M2 to the “no seating recognition mode” M1 can be performed in a short time and with high accuracy.

  FIG. 5 and FIG. 6 show a graph and a flowchart used for the determination process for determining the passenger getting off or turning of the vehicle. Basically, the load value is reduced to a certain range by the load sensors 12a and 12b. Depending on whether the load value is stable within a predetermined fluctuation range, it is determined whether the load is reduced by the passenger getting off or the load is reduced by turning.

  FIG. 5 shows the load fluctuation range for determining whether the passenger gets off or turns. That is, the occupant normally wears the seat belt 13 and puts the seat belt 13 in a non-wearing state when getting off the vehicle. Therefore, immediately after the seat belt 13 changes from the wearing state to the non-wearing state (the buckle switch 14 changes from ON to OFF), it can be said that the probability of getting off is high. During the time tz, the getting-off is determined by the wider load fluctuation range (second threshold) β than the normal narrow load fluctuation range (first threshold) α. In other cases, turning or getting off is determined based on the normal narrow load fluctuation range α.

  Here, it is appropriate to set the wide load fluctuation width β to 5 to 10 times the narrow load fluctuation width α.

  Even if the vehicle seat 11 vibrates and a load fluctuation exceeding the load fluctuation width α is caused by closing the door at the time of getting off or contacting the vehicle seat 11 at the time of getting off by expanding the load fluctuation width, It is possible to determine getting off early and with high accuracy. As a result, the driver's suspicion that the device may be out of order can be dispelled by keeping the airbag display lamp 31 lit even though the passenger gets off.

  FIG. 6 shows a flowchart of the determination process processed by the controller 15, and this flowchart is repeatedly executed at predetermined time intervals.

  First, in step S100, the load value detected by the load detection device 12 is input, and in the subsequent step S102, it is determined whether or not the seat belt 13 is in the mounted state. If the determination result in step S102 is Y (YES), that is, if the seat belt 13 is in the wearing state, the process proceeds to step S104. If N (NO), that is, the seat belt 13 is in the non-wearing state. If there is, the process proceeds to step S106.

  In step S104, it is determined whether or not the seat belt 13 has changed from the wearing state to the non-wearing state (the buckle switch 14 has changed from ON to OFF), and in the case of N, an occupant is seated on the vehicle seat 11. In step S108, it is determined as “occupant seating recognition mode” M2 and stored in the RAM 34 of the controller 15. As a result, the airbag display lamp 31 is turned on.

  On the other hand, if the determination result in step S102 is N, it is determined in step S106 whether or not the load fluctuation is stable within the defined first load fluctuation width α. Here, the first load fluctuation range α is set to a value (for example, 1 kg or less) that is smaller than the load fluctuation range due to cornering and larger than the load fluctuation range due to engine vibration. If the determination result in step S106 is Y, it is determined in step S130 that the occupant has got off the vehicle, and it is determined as “non-sitting recognition mode” M1 and stored in the RAM 34 of the controller 15. As a result, the airbag display lamp 31 is turned off.

  If the determination result in step S104 is Y, then in step S108, it is determined whether or not a fixed time tz has elapsed since the seat belt 13 was changed to the non-wearing state. If the time tz has not elapsed (if the time is within the time tz), it is then determined in step S110 whether or not the load fluctuation is stable within the determined second load fluctuation width β. The second load fluctuation range β here is a sufficiently large value (for example, about 5 to 10 times) as compared with the first load fluctuation range α described above.

  The reason for this is that immediately after the seat belt 13 changes from the mounted state to the non-mounted state, the probability of getting off is high, so the range of load stability is expanded (from the first load fluctuation range α to the second load fluctuation range β). It is intended to make it possible to accurately determine getting off regardless of load fluctuation due to disturbance or the like.

  If it is determined in step S108 that the time tz has elapsed, the process proceeds to step S106 described above, and it is determined whether or not the load fluctuation is stable within the first load fluctuation width α. When it is determined that the vehicle is stable within the load fluctuation range α, it is determined that the occupant has got off the vehicle, and a transition is made to the determination state of “non-sitting recognition mode” M1. On the other hand, when it is determined that the load is not stable, it is determined that the influence is due to turning, and the determination state of the “occupant seating recognition mode” M2 is maintained. Similarly, when the determination result in step S110 is N, it is determined that the influence is due to turning, and the determination state of the “occupant seating recognition mode M2” is maintained.

  The above-described steps S102 and S104 constitute a state change determination unit that determines that the seat belt 13 has changed from the wearing state to the non-wearing state. In addition, the above-described step S106 constitutes a first determination processing unit that shifts to the “non-sitting recognition mode M1” when the load fluctuation range is within the first threshold value α, and the above-described step S110 causes the load to be changed. When the fluctuation range is within the second threshold value β, a second determination processing unit is configured to shift to the “no seating recognition mode M1”.

  According to the above-described embodiment, the seat belt wearing detection unit (buckle switch 14) that detects whether the seat belt 13 is in the wearing state or the non-wearing state, and the left and right sides on the lower side of the vehicle seat 11 The seat belt 13 is changed from the mounted state to the non-mounted state by the load detection device 12 including two load sensors 12a and 12b that detect the load acting on the vehicle seat 11 and the seat belt mounting detection unit 14. In the state change determination unit (S102, S104) for determining whether or not the seat belt 13 is not in the “passenger seating recognition mode” M2, the load detection device 12 When the fluctuation range of the load detected by the vehicle is within the first threshold value α, the occupant is seated on the vehicle seat 11 by getting off the occupant. In the first determination processing unit (S106) for determining that the vehicle is not in the seating state and shifting to the “non-seating recognition mode” M1, and the “occupant seating recognition mode” M2, the state change determination unit (S102, S104) is used to attach the seat belt 13 When it is detected that the state has changed from the state to the non-wearing state, the fluctuation range of the load detected by the load detection device 12 is within a second threshold value β larger than the first threshold value for a predetermined time. In some cases, a second determination processing unit (S110) that determines that no occupant is seated on the vehicle seat 11 by getting off the occupant and shifts to the “no seating recognition mode” M1 is provided.

  As a result, immediately after it is detected that the seat belt 13 has changed from the mounted state to the non-mounted state, it is possible to accurately determine whether the occupant gets out of the vehicle, and from the “occupant seating recognition mode” M2 to the “no seating recognition mode” M1. The transition to can be performed with high accuracy. That is, when the seat belt 13 is changed from the wearing state to the non-wearing state, the probability that the occupant gets off within a predetermined time is high. The passenger getting off can be determined at an early stage in spite of the fluctuation of the vehicle, and it is possible to prevent the airbag display lamp 31 from being lit continuously even if the passenger gets off.

  Further, according to the above-described embodiment, after the seat belt 13 changes from the wearing state to the non-wearing state, the determination is made by the second determination processing unit (S110) for a predetermined time, and after the predetermined time has passed, Since the determination is made by the first determination processing unit (S106), after the seat belt 13 is changed from the wearing state to the non-wearing state, the passenger getting off is accurately determined without overlooking the passenger getting off for a predetermined time. In addition, after the predetermined time has elapsed, by reducing the load fluctuation range, it is possible to eliminate the confusion with the load fluctuation caused by the vehicle turning.

  In the above-described embodiment, the example in which the two load sensors 12a and 12b are arranged before and behind the passenger seat of the left-hand drive vehicle has been described. However, the two load sensors 12a and 12b are provided on the right handle. You may arrange | position before and behind the passenger's seat (right side) of a vehicle, and in this case, the load value detected by the load detection device 12 decreases by the vehicle turning right. Further, the two load sensors 12a and 12b may be arranged before and after the outside (close to the window) of the passenger seat.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the configurations described in the embodiments, and can take various forms within the scope described in the claims. Is.

  DESCRIPTION OF SYMBOLS 10 ... Seat occupant determination apparatus, 11 ... Vehicle seat, 12 ... Load detection apparatus, 12a, 12b ... Load sensor, 13 ... Seat belt, 14 ... Seat belt installation detection part ( Buckle switch), 15 ... Controller, 31 ... Airbag display lamp, M1 ... Seatless recognition mode, M2 ... Passenger seating recognition mode, M3 ... Baggage recognition mode, Steps S102, S104 ... State change judgment unit, Step S106: first determination processing unit, step S110: second determination processing unit.

Claims (2)

A seat occupant determination device that determines whether an occupant seating recognition mode in which an occupant is seated in a vehicle seat or a non-sitting recognition mode in which no occupant is seated in a vehicle seat,
A seat belt wearing detector for detecting whether the seat belt is in a worn state or a non-worn state;
A load detection device comprising two load sensors that are disposed in front of and behind one of the left and right sides of the vehicle seat and detect a load acting on the vehicle seat;
A state change determination unit that determines that the seat belt has changed from a wearing state to a non-wearing state by the seat belt wearing detection unit;
In the occupant seating recognition mode, when the seat belt non-wearing state is detected by the seat belt wearing detection unit, and the fluctuation range of the load detected by the load detecting device is within a first threshold, A first determination processing unit that determines that an occupant is not seated on the vehicle seat by getting off the occupant and shifts to a no-sitting recognition mode;
In the occupant seating recognition mode, when the state change determination unit detects that the seat belt has changed from the wearing state to the non-wearing state, the load detected by the load detection device for a predetermined time is detected. When the fluctuation range is within a second threshold value that is larger than the first threshold value, a second determination processing unit that determines that no occupant is seated on the vehicle seat by getting off the occupant and shifts to the no-sitting recognition mode. When,
A seat occupant determination device.   The determination is performed by the second determination processing unit for a predetermined time after the seat belt is changed from the mounted state to the non-mounted state, and the first determination processing unit is determined after the predetermined time has elapsed. The described seat occupant determination device.

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