JP2004132733A - Vehicle seat load detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle seat load detection device capable of easily detecting an accurate load on a seat by excluding shift of the load on the seat caused by a change with the passage of time of a load sensor or a vehicle attitude. <P>SOLUTION: This device is characterized by being equipped with a load sensor 12 load detection means for detecting the load W applied to a seat device 2, a seating detection sensor 15 object detection means for detecting whether an object is on the seat device 2 or not, an inclination sensor 29 attitude determination means for determining the vehicle attitude, and a controller 8 reference value adjusting means for adjusting a standard value of the load sensor 12 when it is determined that no object exists on the seat device 2 and that the vehicle is in the horizontal state and that an output Wn of the load sensor 12 is a normal value. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle seat load detecting device that can detect a load applied to a vehicle seat and detect a load of an occupant sitting on the seat.
[0002]
[Prior art]
The airbag mounted on the vehicle, especially the airbag on the passenger seat side, determines whether or not to deploy according to the presence or absence of an occupant, and sits on the seat with the shape of the airbag and the gas pressure at the time of deployment. The variable adjustment is performed after confirming the occupant's body shape, for example, whether it is an adult or a child.
Therefore, a weight detection type occupant detection sensor (hereinafter simply referred to as a load sensor) capable of detecting a load applied to the seat is mounted on the vehicle seat device side, the load applied to the seat is detected by the load sensor, and the occupant is seated on the seat. Whether or not the occupant is an adult or a child is recognized by the controller.
[0003]
As a seat device equipped with such a load sensor, for example, a seat connection mechanism in which a seat side and a floor side are pin-coupled with levers that can swing up and down, respectively, is used. Japanese Patent Application Laid-Open No. H11-304579 (Patent Literature 1) discloses a seat device that detects a received load sensor.
[0004]
[Patent Document 1]
JP-A-11-304579.
[0005]
[Problems to be solved by the invention]
By the way, the load sensor incorporating the seat connection mechanism is caused by the temporal deterioration of the inside of the seat connection mechanism, for example, the spring structure, or the body distortion on the floor side or the seat slide rail side of the vehicle body to which the load sensor is attached. When the seat attachment point is displaced, the zero point, which is the reference point of the load sensor, may shift with time.
[0006]
Therefore, when the reference point of such a load sensor shifts, the measurement accuracy of the load on the seat is reduced, and a state may be reached in which the presence or absence and identification of an occupant on the seat cannot be accurately performed.
In order to avoid this, it is necessary to adjust the reference point of the load sensor when the seat is vacant. However, it is difficult to identify whether or not the seat is vacant by only the output of the load sensor.
[0007]
In addition, since the load sensor connected to the seat slide rail in parallel is configured to detect the load via the seat coupling mechanism, the load sensor detects a load in a direction perpendicular to the longitudinal direction of the load sensor. For this reason, as will be described again with reference to FIG. 2 described later, when the vehicle stops on an inclined road having an inclination angle θx, the load W on the seat side is a load Wn = Wcosθx orthogonal to the sensor longitudinal direction and a sensor longitudinal load Wf. = Wsin θx, the load sensor 12 outputs a relatively small value of Wn = Wcos θx as a detection value, and the load W on the seat also shifts due to the inclination of the vehicle.
[0008]
The present invention provides a vehicle seat load detecting device that can easily detect a good on-seat load by eliminating a change in load on a seat due to a change over time of a load sensor or a vehicle posture based on the above-described problems. The purpose is to:
[0009]
[Means for Solving the Problems]
A first aspect of the present invention provides a load detecting unit that detects a load applied to a seat device, an object detecting unit that detects whether an object is present on the seat device, an attitude determining unit that determines an attitude of the vehicle, Reference value adjusting means for adjusting the reference value of the load detecting means when it is determined that there is no object in the device, the vehicle is in a horizontal state, and the output of the load detecting means is at a normal value. It is characterized by.
In this way, regardless of the aging of the load detecting means, the reference value (zero point) of the load detecting means is always adjusted with high accuracy, so that accurate load sensing can be performed. Since the (zero point) is not adjusted, the reliability of the adjustment is improved without being affected by the road surface condition.
Preferably, the determination is made while the vehicle is stopped. In this case, disturbance due to vehicle body vibration can be eliminated, and more accurate load sensing becomes possible.
[0010]
According to a second aspect of the present invention, in the vehicle seat load detecting device according to the first aspect, when the output of the load detecting means is determined to be abnormal, the adjustment is prohibited and a warning instruction is issued to a warning means.
As described above, if the output of the load detecting means is abnormal, the adjustment of the reference point of the load sensor is prohibited, and a warning is issued to the warning means. Adjustment can be prevented.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a vehicle seat load detecting device of FIG. 1 as one embodiment of the present invention will be described.
The vehicle seat load detecting device 1 is mounted on a seat device 2 in a passenger seat (not shown) of a vehicle, and the seat device is mounted on a floor panel 3 of a vehicle body. The seat device 2 is provided with a seat belt 5 for restraining an occupant 4 seated here, and an instrument panel 6 is provided on the front side (left side in FIG. 1). The instrument panel 5 houses an airbag device 11 therein, and a drive circuit 7 of the airbag device 11 is driven and controlled by a controller 8 described later.
[0012]
The airbag device 11 is embedded and mounted in a portion of the instrument panel 6 facing the front passenger seat, and when the airbag 111 is deployed and receives a force equal to or higher than a predetermined pressing force, the skin portion 601 of the instrument panel 6 is opened in the opening direction. It is configured to break and deploy the airbag 111 inside in front of the passenger in the passenger seat. Note that the inflator 112 for deploying the airbag 111 is divided into a plurality of sections, and only the number of inflators to which the explosion signal from the drive circuit 7 is input is blown up, so that the increase and decrease of the deployed gas pressure can be adjusted.
[0013]
The seat device 2 includes a seat body including a seat cushion 9 and a seat back 10. Left and right (front and rear sides of the paper) slide rails 14 provided below the seat cushion 9, and a load mounted on each seat slide rail 14. The vehicle includes a load sensor 12 as a detecting means, and a front-rear bent bracket 13 having front and rear ends of the load sensor 12 attached to the floor panel 3.
[0014]
As shown in FIG. 1, a seating detection sensor 15 is provided inside the seat cushion 9 as object detection means for detecting whether or not an occupant is seated on the seat cushion 9, and this seating signal s0 is output to the controller 8. Is done. Here, the seating detection sensor 15 is a pressure-sensitive film sensor in which a plurality of pressure-sensitive points are arranged and which can detect whether or not the occupant is seated based on the output distribution. Those without are adopted.
[0015]
As the seating detection sensor 15, an infrared sensor or an ultrasonic sensor (not shown) may be used instead of such a pressure-sensitive film sensor. In this case, an infrared sensor or an ultrasonic sensor is mounted on the instrument panel 6 facing the front passenger seat or on a roof (not shown), so that the presence or absence of a passenger in the front passenger seat is output as a seating signal s0. good.
[0016]
The left and right seat slide rails 14 (provided on the front and rear sides in FIG. 1) support the seat cushion 9 so as to be movable in the front and rear direction X with respect to the floor panel 3 and are provided on the left and right end sides of the downward facing surface of the seat cushion 9 respectively. Mounted. Each of the left and right seat slide rails 14 includes an upper rail 141 and a lower rail 142, and the upper rail 141 and the lower rail 142 have a shape in which the upper rail 141 and the lower rail 142 are slidably engaged with each other in a longitudinal direction X, which is a longitudinal direction.
The load sensor 12 includes a detection circuit (not shown) so as to output the load Wn of the occupant 4 when the load W from the seat cushion 9 is received via the seat connection mechanism 19.
[0017]
That is, when the seat connection mechanism 19 of the load sensor 12 transmits the load, if the vehicle stops on a flat ground, the load W = Wn, and there is no problem. However, for example, as shown in FIG. 2, when the vehicle is stopped on a road surface R having an inclination angle θx in the front-rear direction X, the load W applied to the seat connection mechanism 19 of the load sensor 12 is a component in a direction orthogonal to the sensor longitudinal direction. It is divided into Wn = Wcos θx and a longitudinal component Wf = Wsin θx, and the detection value of the load sensor 12 becomes Wn = Wcos θx, which is different from the load W detected on the flat ground. Although FIG. 2 illustrates the case of the road surface R having the inclination angle θx in the front-rear direction X, the case of a road surface having the inclination angle θy (not shown) in the vehicle width direction (the direction perpendicular to the paper surface of FIG. 2) is similarly applied. , A shift occurs with respect to the load W detected on a flat ground. Therefore, when the vehicle stops on the inclined road surface R, it is desirable that the load detection value be canceled.
[0018]
The controller 8 is a well-known electronic control device. An input circuit (not shown) includes a load sensor 12 that captures a load signal Wn, a seating detection sensor 15 that captures a seating signal s0, a vehicle speed sensor 27 that captures a vehicle speed Vc, and a vehicle collision. A collision detection sensor 28 for detecting the acceleration G at the time, and detecting the inclinations θx and θy of the vehicle body in the front-rear direction X and the vehicle width direction Y (perpendicular to the paper surface in FIG. 1), that is, posture determination means for determining the vehicle posture Is connected. Further, a drive circuit 7 of the airbag device 11 and a warning lamp 31 attached to the instrument panel 6 are connected to an output circuit (not shown).
[0019]
Here, as the inclination sensor 29 constituting the attitude determination means, for example, those capable of detecting the inclination angles θx and θy signals of the vehicle body in the front-rear direction X and the vehicle width direction Y using the spirit level principle are employed.
Such a controller 8 has the functions of a load sensor reference point adjustment process 801, an occupant individual recognition process 802, and a deployment drive process 803.
The controller 8 executes a well-known main routine of vehicle control processing, and proceeds to load sensor reference value adjustment processing as reference value adjustment means in the middle of the main routine.
[0020]
In the load sensor reference value adjustment process, when it is determined that there is no object in the seat device 1, the vehicle is in a horizontal state, and the output Wn of the load sensor 12 is at a normal value, the reference value of the load sensor 12 is adjusted. It functions and will be described sequentially.
In step s1 of the load sensor reference value adjustment routine shown in FIG. 3, the load signal Wn, the seating signal s0, the vehicle speed Vc, the inclinations θx and θy in the front-rear direction X and the vehicle width direction Y are fetched and stored in a predetermined data area. Proceed to step s2.
In step s2, the vehicle speed Vc is compared with a stop determination value V1, for example, 4 km / h, and it is determined whether the vehicle is stopped and an IG switch (not shown) is off (off). When the vehicle is stopped, the process proceeds to step s3.
[0021]
In step s3, it is determined whether or not the seating signal s0 is ON. If there is an occupant on the seat, the seat is determined to be seated, and the process returns to the main routine. If the seat is vacant, the process proceeds to step s4.
In step s4, it is determined whether or not the inclination θx, θy of the vehicle body in the front-rear direction X and the vehicle width direction Y exceeds predetermined inclination determination values θαx, θαy, respectively, and at least one of them is higher, that is, If the inclination angle of the road surface is large, the process returns to the main routine, and proceeds to step s5 on a flat ground. In setting the inclination determination values θαx and θαy, a deviation value between a load applied to the seat device 2 detected on a flat ground and a load Wn actually detected by the load sensor 12 is experimentally sampled in advance. . Then, it is appropriately set whether or not the load deviation is allowable. Then, the inclination determination values θαx and θαy corresponding to the allowable deviation value are appropriately set and adopted.
[0022]
In step s5, the allowable width of the load Wn when the load sensor 12 is vacant is set in advance, for example, is set to within ± 5 kg, and it is determined whether or not the current load Wn when vacant is smaller than this allowable width. If it is small and normal, the process proceeds to step s6. Otherwise, the sensor is regarded as abnormal, and the process proceeds to step s7.
In step s7, the number of times of sensor abnormality determination is counted a predetermined number of times. Before counting up, the process returns to the main routine. After counting, the process proceeds to step s8, where the warning lamp 31 is turned on, and the process returns to the main routine. Note that the count value here may be a value that can prevent disturbance, and is processed so as to be cleared when the engine key is turned off or every predetermined traveling distance.
[0023]
As described above, the load Wn when the seat is vacant is originally zero, but if the deterioration over time progresses excessively, the zero point, which is the reference value, is shifted until it exceeds ± 5 kg, which exceeds the reference point adjustable level. As a result, it is determined that repair or replacement is necessary.
On the other hand, if the load Wn at the time of vacancy is within the allowable range from step s5 and reaches step s6, the load sensor 12 is at the level where the reference point can be adjusted. And a plurality of values before this time are sequentially updated and stored in the same manner. Then, an average value Wnf = {Wn (n) + Wn (n−1) + Wn (n−2) +... + Wn (1)} / n of the load when the seat is vacated a plurality of times is calculated. As a result, the load Wn when the seat is vacant can be prevented from increasing or decreasing due to disturbance, and the reliability of control can be improved.
[0024]
When step s9 is reached from step s6, the average value Wnf of the unoccupied seat load is set as a reference point adjustment amount (deviation adjustment amount) ± α for correcting the average value Wnf of the load sensor 12 to a zero point which is a reference point of the load sensor 12, and is set to a predetermined value. , And the current control is terminated, and the process returns to the main routine.
Next, as the occupant solid recognition processing 802 performed by the controller 8, first, when the vehicle is stopped, the vehicle stops on a flat surface where the inclinations θx and θy in the front-rear direction X and the vehicle width direction Y are lower than the inclination determination values θαx and θαy, respectively. When the determination is made, and when the seating detection sensor 15 detects the input of the seating signal s0, the load Wn of the load sensor 12 at that time is captured.
[0025]
At this time, the controller 8 may correct the latest average load Wnf with the reference point adjustment amount (deviation adjustment amount) α to obtain the load W (= Wnf− (± α)) in the state where the zero point is adjusted. it can. Since the load W adjusted to the zero point is used, even if the load sensor 12 has deteriorated with time, its influence can be eliminated, and reliable load W data can be adopted.
Next, the level of the load Wn is classified into, for example, large, medium, small, and no load (when not seated) using a threshold appropriately set.
[0026]
In the deployment driving process 803 performed by the controller 8, first, the airbag gas pressure is variably set according to the category of the load Wn. In other words, when the load category is large or medium, the airbag operation mode is set so that the gas pressure is at the maximum level (all the inflators are detonated) and the gas pressure is at the middle level (all the inflators are partially detonated). I do. Further, when the load output is small or no load is applied, the gas pressure is set to zero, that is, the airbag non-operation mode is set.
Next, when the vehicle travels, the latest airbag deployment (operation mode) condition is read first to determine whether the current vehicle speed Vc exceeds the vehicle speed at which the airbag deployment is required at the time of a vehicle collision, for example, 20 km / h. Judge.
[0027]
Then, the latest acceleration G of the collision sensor 28 is fetched, and it is determined whether or not this value exceeds a predetermined threshold for judging a vehicle collision. Considering the time, the explosion signal from the drive circuit 7 is input to the number of inflators 112 corresponding to the current airbag operation mode, the airbag is exploded and deployed, and the airbag corresponding to the body shape of the passenger in the passenger seat is generated. The deployment process can be performed and safety can be ensured.
As described above, since the vehicle seat load detecting device 1 of FIG. 1 performs the load sensor reference point adjustment processing shown in FIG. 4, the reference value (zero point) of the load sensor 12 is always obtained regardless of the aging of the load sensor 12. Can be adjusted with high accuracy, and accurate sensing of the occupant load Wn can be performed.
[0028]
In particular, when performing the adjustment of the reference value (zero point), it is possible to perform processing to make a determination while the vehicle is stopped in step s2, to eliminate disturbance due to vehicle body vibration, and to accurately sense the load sensor 12 when the seat is empty. .
Furthermore, by performing the flat road determination in step s4 of the load sensor reference point adjustment routine, it is possible to eliminate the reference value (zero point) adjustment on the slope, prevent erroneous adjustment, and is not affected by the road surface condition. And the reliability of the reference value (zero point) adjustment is improved.
[0029]
Moreover, when it is determined in step s5 of the load sensor reference point adjustment routine that the output of the load sensor 12 is abnormal, the load sensor reference point adjustment in steps s6 and s7 is prohibited, and the warning light 31 is turned on to issue a warning instruction. It is possible to notify the occupant of the failure of the load sensor 12 easily and promptly, so that repair and the like can be quickly performed.
[0030]
In the load sensor reference point adjustment processing of the vehicle seat load detection device 1 of FIG. 1, the warning lamp 31 is turned on to give a warning instruction when the number of times of the sensor abnormality determination is counted up by a predetermined number of times in step s7. The control may be simplified by directly reaching step s8 from step s5 and turning on the warning lamp 31 to give a warning instruction.
[0031]
In the load sensor reference point adjustment process of the vehicle seat load detection device 1 of FIG. 1, when it is determined in step s5 that the current load Wn when the seat is empty is within the allowable range of the load Wn when seat is empty, the normal state is determined in step s6. The average value Wnf of the unoccupied load Wn is calculated, and the same value Wnf is set as the reference point adjustment amount (deviation adjustment amount) ± α of the load sensor 12. However, in some cases, the process directly proceeds from step s5 to step s9. May be set as the reference point adjustment amount (deviation adjustment amount) ± α of the load sensor 12 to simplify the control.
[0032]
【The invention's effect】
As described above, according to the present invention, the reference value (zero point) of the load detecting means is always adjusted with high accuracy regardless of the aging of the load detecting means. Since the reference value (zero point) is not adjusted on the road, the reliability of the adjustment is improved without being affected by the road surface condition.
[0033]
According to the second aspect of the invention, when the output of the load detecting means is abnormal, the adjustment of the reference point of the load sensor is prohibited, and a warning is issued to the warning means, so that the failure of the load detecting means can be notified to the occupant. Incorrect adjustment can be prevented.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a seat device equipped with a vehicle seat load detection device as one embodiment of the present invention.
FIG. 2 is an explanatory diagram illustrating a load distribution in an inclined state of a load sensor used in the vehicle seat load detecting device in FIG. 1;
FIG. 3 is a flowchart of a load sensor reference value adjustment routine executed by a controller of the vehicle seat load detection device in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle load detection device 2 Seat device 6 Instrument panel 8 Controller (reference value adjusting means)
11 Airbag device 12 Load sensor (load detection means)
15 Seating detection sensor (object detection means)
29 Tilt sensor (posture determination means)
Output of Wn load sensor

Claims (2)

Load detecting means for detecting a load applied to the seat device;
Object detection means for detecting whether or not there is an object on the seat device;
Attitude determination means for determining the attitude of the vehicle,
Reference value adjusting means for adjusting the reference value of the load detecting means when it is determined that there is no object in the seat device, the vehicle is in a horizontal state, and the output of the load detecting means is at a normal value,
A vehicle seat load detecting device comprising: The vehicle seat load detecting device according to claim 1,
When the output of the load detecting means is determined to be abnormal, the adjustment is prohibited and a warning instruction is issued to a warning means.

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