JP2003118531A - Occupant position detecting device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an occupant position detecting device for a vehicle capable of surely detecting the position and the posture of an occupant without performing complicated signal processing such as image recognition. SOLUTION: An optical distance surveying sensor 1 is provided in a backrest part 12 of a seat 10 to measure the distance to the back surface of the occupant. An occupant absolute position is obtained from the distance and the seat position to contribute to the development control of the air bag.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle occupant position detecting device.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 10-119
Japanese Patent No. 715 discloses a determination target that optically detects a distance to a plurality of optical sensor determination targets and stores each obtained distance data in advance in order to enhance a passenger occupant protection function, particularly a passenger seat occupant protection function at the time of a collision. It proposes a technique for judging the shape of the judgment target by comparing it with the judgment model information.

According to this technique, the physique and position of the occupant to be judged can be recognized in advance, so that airbag deployment control at the time of a vehicle collision can be suitably performed based on this information. .

[0004]

However, in the above-mentioned publication, a distance measuring method (hereinafter referred to as an optical distance measuring method) for obtaining the distance information by an optical sensor arranged rearward on a front end position of a vehicle body ceiling surface or a dashboard or the like. It has been found that the movement of the occupant's hand in front of the occupant's body causes the detection distance data to be greatly confused because the front distance measurement method is used. In particular, this problem is exacerbated when an occupant holds an item in his hand. It is theoretically possible to remove movements of the occupant's hands and movements of the carried objects by image processing, but it is necessary to accurately realize such complicated image processing in an extremely short time, for example, at the time of a collision. Is not easy, and at the present stage it is far from practical use. Therefore, it is not preferable to perform airbag deployment control at the time of a collision based on the occupant position formed without removing these false signals from the detected distance measurement data obtained by the current optical front distance measurement method. Deployment control may be selected, which is not preferable.

Similarly, a distance measuring system (hereinafter also referred to as an optical lateral surface distance measuring system) for obtaining the above distance information by an optical sensor disposed laterally at a position on the seat side of the vehicle body has been proposed. However, in this case as well, it was found that the movement of the hand or the article held in the hand gives a large noise to the determination of the position, posture and shape of the occupant, and the same problem as the above-mentioned optical front distance measuring method occurs. . Further, in this optical lateral distance measuring method, there are problems that a measurement target area in front of the distance measuring sensor to be monitored is wide and it is not easy to secure a storage space for the distance measuring sensor.

Further, in these optical front distance measuring method and optical side surface distance measuring method, external light (sunlight (infrared ray) or reflected light thereof) is incident on the distance measuring sensor or the lighter is ignited. However, there is also a problem that the removal process is troublesome.

As a result, the conventional optical front distance measuring method and the optical lateral distance measuring method have a problem that the signal accuracy is deteriorated due to a false signal such as incident of external light or movement of a passenger's hand.

The present invention has been made in view of the above problems, and provides a vehicle occupant position detection device capable of reliably detecting the occupant position and occupant posture without performing complicated signal processing such as image recognition processing. The purpose is to do.

[0009]

A vehicle occupant position detecting device according to the present invention is provided on a seat back portion of a seat, and provides information on a relative position of a predetermined area on the back of the upper half of the body of a seated occupant with the back portion as a reference. It is characterized in that it has an occupant relative position detecting means for detecting contact.

According to the present invention, since the sensor is provided on the backrest and the rear distance measuring system is adopted, the occupant's hands and hands can be compared with the conventional optical lateral distance measuring method and optical front distance measuring method. Since it is possible to reduce the influence of the movement of the carried object and erroneous detection due to strong external light incident from the outside, it is possible to detect the occupant position with high accuracy without complicating the circuit configuration and signal processing. .

The relative distance to the position of the occupant's backrest is important and useful information in controlling the deployment of the airbag. For example, a large relative distance suggests that at least the upper half of the occupant's upper body is in front, and rapid deployment of the airbag is desired during airbag deployment control. In addition, the fact that this relative distance is small suggests that the upper half of the occupant's upper body is behind, and it can be determined that rapid deployment of the airbag is not so required during airbag deployment control. Furthermore,
A large relative distance at the upper part of the backrest and a small relative distance at the lower part of the backrest means that the upper half of the occupant's upper body is in a large forward leaning position or a small child is seated. It can be directed to select the appropriate airbag deployment control.

In a preferred mode 1, the backrest position detecting means for detecting the position of the backrest, and the relative position of the occupant with respect to the vehicle body are defined based on the detected backrest position and the relative position, respectively. And an occupant absolute position determination means for determining the occupant absolute position. Thereby, the position of the occupant with respect to the vehicle body can be determined more accurately by adding the obtained relative position of the occupant and the backrest position.

In a preferred mode 2, there is provided occupant state determining means for determining the physique or posture of the occupant based on the distance information to the plurality of parts of the occupant input from the occupant relative position detecting means.

That is, in this configuration, the physique and posture of the occupant are determined based on the distances to a plurality of parts of the occupant.
For example, the optimum control can be further executed in the airbag deployment control.

In a preferred mode 3, the occupant relative position detecting means has a plurality of distance measuring sensors which are arranged apart from each other on the backrest portion and measure different front spaces. This eliminates the need for two-dimensional scanning or one-dimensional scanning of the front space by a single sensor, thus simplifying the circuit system.

In a preferred mode 4, the occupant state determining means estimates the head position of the occupant based on the forward leaning angle of the occupant calculated based on the distance measurement data detected by the distance measuring sensors. . As a safety measure against a collision, recognition of the occupant's head is particularly important in airbag deployment control, for example. It is most preferable to directly measure the position of the head, that is, the uppermost position on the back of the occupant, but when the occupant is in a large forward bending posture, it may be difficult or inaccurate to detect the head position. Therefore, in such a case, if the forward inclination from the waist to the upper part of the occupant's back is determined, the waist-to-head length (upper body height) measured in advance is used, The head position can be estimated almost accurately.

In a preferred aspect 5, the occupant relative position detection means, the occupant absolute position determination means, or the occupant state determination means uses the detected or determined relative position or absolute position or attitude or shape information of the occupant as an airbag. It is output to the airbag deployment control means that controls deployment. As a result, the airbag deployment control can be optimally performed according to the position, posture, and shape of the occupant, and the damage at the time of a collision can be minimized. For example, the airbag deployment control means speeds up the airbag deployment control when the occupant position is in front of when it is behind. Further, when the occupant is leaning forward and the child is standing on the seat or on the floor in front of the seat, appropriate airbag deployment control is performed according to the situation. When the occupant is small, the airbag deployment pressure is weakened to reduce the impact on the occupant. Since various concrete methods of airbag deployment control based on such occupant information are not the gist of the present invention and are publicly known, further description will be omitted.

In the sixth preferred embodiment, an optical non-contact distance sensor can be used as the occupant relative position detecting means. As the optical non-contact distance sensor, various known methods of detecting the distance to the measurement object using light directly or by image processing can be adopted, and it is preferable to use the infrared wavelength as the light wavelength to be used. However, it is of course possible to use wavelengths in the visible region. Examples of the optical non-contact distance sensor include a so-called active distance measurement method that uses reflected light of a light beam emitted from a laser or an LED to a predetermined portion, or images of a plurality of linear or area image sensors whose optical axes are offset. It is possible to use a so-called passive distance measurement method or the like in which distance measurement is performed based on comparison. In a preferred embodiment, the optical non-contact distance sensor can be arranged in the space between the seat back portion and the headrest. With this configuration, it is possible to reduce the possibility that the non-contact distance sensor rubs against the back of the occupant, causes the occupant's back to feel uncomfortable, or exposes the lens or the like to the backrest. The occupant's posture (front-back direction) can be detected by measuring the distances of the respective parts on the back of the occupant, which is particularly important in airbag control. For such distance measurement of a plurality of areas, a two-dimensional passive method using a pair of area image sensors, a two-dimensional active method in which a large number of active distance measuring devices are arranged in a two-dimensional matrix on the backrest at a predetermined pitch, A spatial scan method of scanning the target space with a beam can be adopted. The distance may be measured in the front-rear horizontal direction of the vehicle body from the backrest portion, or may be measured diagonally.

In the preferred aspect 7, an ultrasonic non-contact distance sensor can be adopted as the occupant relative position detecting means. According to this configuration, it is possible to detect the distance to the back of the occupant without having to worry about dirt on the lens or incidence of external light. Of course, this ultrasonic non-contact distance sensor may be arranged between the backrest and the headrest.

The ultrasonic transducers can be two-dimensionally arranged at a predetermined pitch on the backrest portion, and each ultrasonic transducer has an ultrasonic beam having a narrow divergence angle from a minute hole provided in the backrest portion to a near front space. May be emitted respectively. Alternatively, an ultrasonic beam may be emitted from a predetermined position of the backrest with a large divergence angle, and the ultrasonic beam for reception provided in each part of the backrest may receive the ultrasonic beam. After the transmission, the ultrasonic transducer for transmission can also serve as the ultrasonic transducer for reception, and the distance can be measured by multiplying the delay time from transmission to reception by the sound wave speed and dividing by 2. .

When a plurality of ultrasonic transducers for transmission are used, it is preferable to perform time-sequential processing by shifting the ultrasonic wave emission timings in time. This simplifies the circuit system by forming the voltage applied to these transmitting ultrasonic transducers with one transmitting circuit system and distributing the voltage to each transmitting ultrasonic transducer by the demultiplexer in time sequence. In addition, it is possible to prevent the ultrasonic waves emitted from the plurality of ultrasonic transducers for transmission from being mixed. Of course, it is also possible to discriminate according to the frequency by making the oscillation frequency of each ultrasonic transducer for transmission different.

When a plurality of ultrasonic transducers for reception are used, it is preferable to perform time-sequential processing by shifting the effective ultrasonic wave reception periods. As a result, the signal voltage output by these ultrasonic transducers for reception can be formed by one reception transmission circuit system, and the reception voltage of each ultrasonic transducer for reception can be sequentially processed by the multiplexer. The circuit system can be simplified.

A large number of ultrasonic transducers for transmitting and receiving ultrasonic waves can be formed by providing electrodes on a predetermined portion of a single film-shaped piezoelectric sheet. It is also possible to integrate the processing circuit module.

In a preferred mode 8, an alternating current antenna type non-contact distance sensor can be used as the occupant relative position detecting means. According to this configuration, the sensor can perform detection through the surface cover of the sheet or the like, so that the aesthetic appearance can be improved as compared with the optical type. Of course, this AC antenna type non-contact distance sensor may be arranged between the backrest and the headrest. This AC antenna type non-contact distance sensor (hereinafter, also referred to as an AC impedance sensor) is composed of, for example, a pair of electrodes embedded in the backrest at a predetermined distance from each other, and the AC impedance between these electrodes is close to that of the human body. The phenomenon that is modulated by the degree of is used. At high frequencies, the human body can be regarded as a substantially conductor or low resistance body, and the spatial distance between each electrode and their local surface of the adjacent human body is inversely proportional to the capacitance between them. Such electrostatic capacitance detection can be easily detected as a current change or an oscillation frequency change. Of course, the circuit system can be simplified by the time-sequential method using the demultiplexer and the multiplexer described in the section of the ultrasonic transducer.

With this AC impedance detection method,
Since the electrodes can be embedded in the backrest, it is possible to avoid a decrease in aesthetics and an increase in discomfort. For example, if a large number of electrodes are two-dimensionally arranged on the backrest at a constant pitch and the AC impedance between adjacent electrodes is detected, the spatial resolution can be further improved with a simple configuration. In this case, a higher signal frequency can improve the measurement resolution of the front target space.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be specifically described with reference to the following examples. (Embodiment 1) An embodiment of a vehicle occupant position detecting device of the present invention will be described below with reference to FIGS. 1 and 2
In the figure, 1 is an optical non-contact distance sensor (occupant relative position detecting means, hereinafter also simply referred to as an optical distance measuring sensor),
2 is a seat position sensor, 4 is a signal processing circuit, 5 is an airbag control unit, and 10 is a seat.

The seat 10 has a seating portion (seat) 11 and a backrest portion (seat back) 12, and constitutes a so-called passenger seat.

The optical distance measuring sensor 1 is embedded in the upper part of the backrest 12 to measure the distance to the object in the target area in the space in front of the seat 10, and the rear surface of the seated person in the target area. Detects the distance to the section.

In this embodiment, the distance measuring sensor 1 is a projection type triangulation device having a light projecting element 100, a light receiving element 101, a projection lens system 102 and a light receiving lens system 103, as shown in FIG. It is composed of a distance sensor. Projector 1
Reference numeral 00 is composed of a light emitting diode or a semiconductor laser element that projects light through the projection lens system 102.
Reference numeral 01 is composed of a PSD sensor, a CCD linear sensor, a photodiode linear array, and the like, and detects the distance to the object using a known triangulation method. That is, the optical axis of the projection lens system 102 and the optical axis of the light receiving lens system 103 are set parallel to each other with a predetermined distance d therebetween.
3 is x, the distance between the imaging point of the reflected beam incident on the light receiving element 101 and the optical axis of the light receiving lens system 103 is x, the distance between the light receiving lens system 103 and the light receiving element 101 is d ′, and the projection lens system 102 is If the distance to the object is L, then L =
d · d ′ / x, which can be easily detected.

This type of projection type (active) optical distance measuring sensor is well known as being used for distance measuring of a camera and the like, and this type of triangular distance measuring method itself is not the gist of the present invention. Description is omitted.

As the distance-measuring sensor 1, various optical passive distance-measuring devices, such as those for estimating the distance by comparing and matching the output images of two image sensors having parallel optical axes apart from each other, and further emitting Various known distance measuring methods can be used, such as an ultrasonic distance measuring method for measuring the distance by returning the reflected signal of the ultrasonic wave. In addition, as a simple distance detection method, it is also possible to detect whether or not the target has approached by the change in the AC impedance associated with the electrode facing the target space.

In this embodiment, the seat position sensor 2 is composed of a plurality of limit switches arranged at a predetermined pitch in the front-rear direction on the floor of the seat bottom, or the rotation angle of a roller that rotates in accordance with the front-back movement of the seat. The rotation angle detection sensor for detecting In the former case, for example, a protrusion (or a magnet) is provided as a detector on the seat side, and the front-back direction zone in which the seat is present can be detected depending on which limit switch the detector passed in which direction. Further, the rotary roller type sensor can detect the seat position in an analog manner.

The signal processing circuit 4 adds the relative position of the occupant to the backrest of the seat obtained from the distance measuring sensor 1 and the absolute seat position obtained from the seat position sensor 2 to obtain the occupant absolute position. The state of the occupant is determined, and the occupant state information is transmitted to the airbag control unit 5, and the airbag control unit 5 adjusts the inflation control of the airbag (not shown) based on the obtained absolute position of the occupant. FIG. 4 shows an example of the occupant absolute position output by the signal processing circuit 4 and the actual occupant state determined thereby.

(A) is a case where the distance measuring sensor 1 measures a long distance equal to or more than a predetermined value, and this is judged to be the case where there is no occupant. It is also possible to determine the seat position based on this distance, and then add the seat position change amount from this seat position to determine the current seat position. In this case, it is not always necessary to perform airbag deployment control even at the time of a collision.

(B) is a case where the distance measuring sensor 1 measures a short distance less than a predetermined value, which is determined as a normal sitting state in which the back surface of the occupant is substantially in close contact with the backrest 12. In this case, the airbag deployment control is performed in a regular time at the time of collision.

(C) is a case where the distance measuring sensor 1 measures the distance between the above (a) and (b), which means that the occupant is leaning forward or the child is more than the backrest 12. It is determined that there is a distance to the front. In this case, the airbag deployment control is performed in a shorter time than the regular time at the time of collision.

[0037]

Second Embodiment Another embodiment will be described below with reference to FIG.

This embodiment employs a multi-point distance measuring system in which the optical distance measuring sensor 1 described in the first embodiment is arranged in a matrix in the backrest portion 3 × 4. Each optical distance measuring sensor 1 is of the light beam projection type shown in FIG. 3, whereby the space in front of the backrest 12 is divided into 12 and distance measuring data can be obtained for each small space. In this way, as shown in FIG. 6, in addition to the accurate distinction between the adult normal seat and the adult forward lean seat, the normal seat of the child and its front seat and standing up are discriminated as shown in FIG. You can also

[0039]

Third Embodiment Another embodiment will be described below with reference to FIG.

In this embodiment, the matrix arranged optical distance measuring sensor 1 described in the second embodiment is replaced with a matrix arranged ultrasonic distance measuring sensor 100.

This matrix-arranged ultrasonic distance measuring sensor 1
00 is composed of a total of 12 ultrasonic transducers 101 to 112 arranged in a 3 × 4 matrix, and is embedded in the backrest 12. 121 is an oscillation circuit, 122 is an analog demultiplexer, 123 is an analog multiplexer, 1
24 is a counter. 121 is an oscillation circuit, 122 is an analog demultiplexer, 123 is an analog multiplexer, 124 is a narrow band (tuning) filter, 125 is a full-wave rectifier circuit, 126 is a comparator, and 127 is a counter.

The oscillating circuit 121 oscillates and amplifies a high frequency AC voltage of 100 kHz or more, and distributes it to the ultrasonic transducers 101 to 112 through the analog demultiplexer 122 in time sequence. The ultrasonic transducers 101 to 112 emit an ultrasonic beam having a narrow divergence angle forward only during a period in which the AC voltage is applied from the analog demultiplexer 122, and then change the reflected beam into an AC signal voltage as a receiving element. The analog multiplexer 123 is the ultrasonic transducer 1.
01 to 112, the signal voltage from the ultrasonic transducer immediately after emitting the ultrasonic beam is selected and amplified, and the narrow band (tuning) filter 124 causes the oscillating circuit 121 in the signal voltage to be selected.
The full-wave rectification circuit 125 rectifies the extracted frequency band. The rectified voltage is the comparator 12
It is binarized by 6 and input to the count stop terminal of the counter 127. Since the counter 127 counts the input clock pulse from the time when the ultrasonic beam of the corresponding ultrasonic transducer is emitted, the count value at the time when the counter 127 stops counting is from the backrest portion 12 to the front occupant rear area. Proportional to the round trip distance. Since the reflection of the surface cloth of the backrest 12 is weak, it is removed by the comparator 126. As a result, the same function as that of the first embodiment can be realized.

[0043]

Fourth Embodiment Another embodiment will be described below with reference to FIG.

In this embodiment, the matrix arranged ultrasonic distance measuring sensor 100 described in the third embodiment is replaced with a matrix arranged AC impedance sensor 200.

This matrix-arranged AC impedance sensor 200 has a total of 12 arranged in a 3 × 4 matrix.
It is composed of individual electrodes and is embedded in the backrest 12.
Reference numerals 201 to 204 denote electrodes for one vertical column.

By using the analog demultiplexer shown in FIG. 8 or a circuit similar to the analog multiplexer, the adjacent electrode pairs 201 and 202, the adjacent electrode pairs 202 and 203, and the adjacent electrode pairs 203 and 204 are time-sequentially, for example, several numbers. Ten ~
An AC voltage of several hundred kHz or more is applied and the voltage drop between these adjacent electrodes is measured.

Since the human body can be regarded as a good conductor, when the back of the occupant is in the normal sitting position 300,
The electrostatic capacitance CH between the adjacent electrode pairs 201 and 202 can be regarded as a combined capacitance of the approximately electrostatic capacitances C1 and C2, and the electrostatic capacitance CM between the adjacent electrode pairs 202 and 203 is approximately the electrostatic capacitance C2. And C3 can be regarded as a series-connected combined capacity, and the electrostatic capacity CL between the adjacent electrode pairs 203 and 204 can be regarded as a series-connected combined capacity of substantially electrostatic capacity C3 and C4. Therefore, if a circuit similar to FIG. 8 is used,
The alternating-current signal voltage according to these capacitance values can be subjected to time-sequential sampling processing. However, in this embodiment, instead of the comparator 126 and the counter 127, the rectified voltage of the received analog AC voltage is A / D converted and the capacitance is estimated based on the magnitude thereof.

On the other hand, when the back surface of the occupant is in the forward leaning seat position 301, the electrostatic capacitances CH and CM between the adjacent electrode pairs 201 and 202 are very small, and the adjacent electrode pair 2
Since the capacitance CL between 03 and 204 does not change so much, it can be determined that the seat is leaning forward. In addition, 120 is a surface position of the backrest 12.

(Modification) In each of the above-mentioned embodiments, the posture and the position are mainly determined by the distance data of one point or multiple points, but it is also possible to determine the shape of the occupant by using the multipoint data.

[Brief description of drawings]

FIG. 1 is a schematic block circuit diagram showing a first embodiment of the present invention.

2A is a front view showing the seat of FIG. 1, and FIG. 2B is a side view showing the seat of FIG.

FIG. 3 is a schematic diagram showing the principle of the optical distance measuring sensor of FIG.

FIG. 4 is a schematic diagram showing the relationship between optical distance measurement data and occupant posture according to the first embodiment.

FIG. 5 is a front view of a seat used in a second embodiment of the present invention.

FIG. 6 is a schematic diagram showing the relationship between optical distance measurement data and occupant posture according to the second embodiment.

FIG. 7 is a schematic diagram showing the relationship between optical distance measurement data and occupant posture according to the second embodiment.

FIG. 8 is a block circuit diagram showing an ultrasonic distance measuring system according to a third embodiment.

FIG. 9 is a block circuit diagram showing an AC impedance ranging method according to a fourth embodiment.

[Explanation of symbols]

1 Optical distance measuring sensor (passenger relative position detection means) 2 Seat position sensor (backrest position detection means) 4 Signal processing circuit (passenger absolute position determination means, occupant state determination means) 5 Airbag control section 10 seats

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hironori Sato             14 Iwatani Shimohakaku-cho, Nishio-shi, Aichi Stock Association             Company Japan Auto Parts Research Institute (72) Inventor Tomoyuki Goto             14 Iwatani Shimohakaku-cho, Nishio-shi, Aichi Stock Association             Company Japan Auto Parts Research Institute (72) Inventor Katsuyuki Imanishi             14 Iwatani Shimohakaku-cho, Nishio-shi, Aichi Stock Association             Company Japan Auto Parts Research Institute F term (reference) 3D054 AA03 EE11 FF16

Claims (6)

[Claims] 1. An occupant relative position detecting means, which is mounted on a back portion of a seat, for non-contactly detecting information on a relative position of a predetermined region on the back of the upper half of the body of a seated occupant with the back portion as a reference. Vehicle occupant position detection device. 2. The vehicle occupant position detecting device according to claim 1, wherein the backrest position detecting means for detecting the position of the backrest portion, and the backrest portion position and the relative position respectively detected, A vehicle occupant position detection device comprising: an occupant absolute position determination means for determining an occupant absolute position defined as a relative position of the occupant with respect to a vehicle body. 3. The vehicle occupant position detecting device according to claim 1, wherein the physique or posture of the occupant is determined based on each distance information to the plurality of parts of the occupant input from the occupant relative position detecting means. An occupant position detection device for a vehicle, comprising an occupant state determination means for determining. 4. The vehicle occupant position detection device according to claim 3, wherein the occupant relative position detection means includes a plurality of distance measurement sensors that are arranged apart from each other on the backrest portion and measure different front spaces. A vehicle occupant position detection device characterized by the above. 5. The vehicle occupant position detection device according to claim 4, wherein the occupant state determination means is based on the forward inclination angle of the occupant calculated based on each distance measurement data detected by each distance measurement sensor. An occupant position detecting device for a vehicle, which estimates the head position of the occupant by means of a vehicle. 6. The vehicle occupant position detection device according to any one of claims 1 to 5, wherein the occupant relative position detection means, the occupant absolute position determination means, or the occupant state determination means detects or determines the occupant. Relative position or absolute position or attitude or shape information of
An occupant position detection device for a vehicle, which outputs to an airbag deployment control means for performing airbag deployment control.