Method for determining the height and weight type of a seat occupant

Abstract

The invention relates to a method for determining the height and weight of a seat occupant; the method comprising: - a calculation (44) of a first value representing the pressure exerted on the seat from the resulting capacitance value of a first capacitive sensor with interdigitated electrodes located on the first lateral support edge and a resulting capacitance value of a second capacitive sensor with interdigitated electrodes located on the central part of the seat, - a calculation (46) of a second value representing the pressure exerted on the first lateral support edge of the seat from the resulting capacitance value of the first capacitive sensor, - a calculation (48) of a first value as a function of the first and second values, - a comparison (50) of the first value to a first threshold, generating a signal when the first value is lower than the first threshold. Figure to be published with the abbreviation: Figure 3

Description

Title of the invention: Method for determining the height and weight type of a seat occupant Technical field of the invention

[0001] The present application relates to a method for determining the staturoponderal type of a seat occupant. Prior art

[0002] There is a growing demand for devices to determine the type of occupant of a seat, in particular a vehicle seat, whether it is a driver or a passenger. These detection devices typically employ sensors such as a camera or a motion sensor located above the seat. However, measurements obtained using such devices generally have a long response time, on the order of several seconds, which is unsuitable for providing sufficiently rapid data in certain situations, particularly in the event of an accident. For example, there is a need to be able to adapt the properties of an airbag system designed to protect a vehicle seat occupant in the event of an accident. Thus, the operation of existing systems could be improved by adjusting the properties of an airbag and / or a vehicle seat belt pretensioner based on real-time knowledge of parameters such as the type of user, their height, weight, etc. Furthermore, the measurements obtained by such devices often lack robustness. In addition, the measurements taken by these devices exhibit drift over time. These devices are therefore unsuitable for applications in the automotive sector, where a reliability period of at least ten years is required. Summary of the invention

[0003] In order to address the aforementioned drawbacks and to meet this or these needs, the present invention relates to a method for determining the height and weight of an occupant of a seat, in particular a vehicle seat; the seat comprising a cushion, the cushion comprising a central part and a first lateral support edge; the method comprising: - a calculation of a first representative data point of the pressure exerted on the seat from the resulting capacitance value of a first capacitive sensor with interdigitated electrodes located on the first lateral support edge and at least one value of resulting capacity of a second capacitive sensor with interdigitated electrodes located on the central part of the seat, - a calculation of a second representative data point of the pressure exerted on the first lateral support edge of the seat, based on the resulting capacitance value of the first capacitive sensor, - a calculation of a first value based on the first and second data points, - a comparison of the first value to a first threshold, when the first value is less than the first threshold, generation of a signal representative of a child-type occupant.

[0004] The features described in the following paragraphs may optionally be implemented. They may be implemented independently of each other or in combination with each other: - the calculation of the first value includes a sum of the first data and the second data. - the calculation of the first data includes the calculation of a sum weighted by a weighting coefficient, of the resulting capacity values ​​of the capacitive sensors located on the base. - the seat includes a second lateral support rim, and the first data is calculated from the resulting capacitance value of the first capacitive sensor, the resulting capacitance value of at least the second capacitive sensor and a resulting capacitance value of a third capacitive sensor with interdigitated electrodes located on the second lateral support rim of the seat; the second data being calculated from the resulting capacitance value of the first capacitive sensor and the resulting capacitance value of the third capacitive sensor; the second data being representative of the pressure exerted on the first lateral support rim and on the second lateral support rim. - The weighting coefficient comprises a ratio between a non-zero natural number and a representative value of the pressure exerted on at least the first lateral edge. - The weighting coefficient comprises a ratio between a non-zero natural number and an average of a resulting capacitance value from the first capacitive sensor and a resulting capacitance value from the third capacitive sensor. - the second data includes the sum of a resulting capacitance value from the first capacitive sensor and a resulting capacitance value from the third capacitive sensor. - The second piece of data is the resulting capacitance value of the first capacitive sensor. The process involves: - the initialization of a first counter and a second counter, - a comparison of the second data point to a second threshold; if the second data point is less than the second threshold, then increment the first counter by a first number. if the second data is greater than the second threshold then increment the second counter by said first number; said first number being strictly greater than zero. - The method includes calculating a second value based on a resultant value from the second capacitive sensor and a resultant value from a fourth capacitive sensor with interdigitated electrodes located in a median area of ​​the central part of the base, the second capacitive sensor being located in a median area of ​​the central part of the base; comparing the second value to a third threshold, if the second value is less than the third threshold, then increment the first counter by a second number, if the second value is greater than the third threshold, then increment the second counter by the second number, the second number being strictly greater than zero. - The method includes: defining a second value equal to (or setting a second value equal to) a resultant value from at least one second capacitive sensor, the second capacitive sensor being located in a median area of ​​the central part of the seat; - a comparison of the second value to a third threshold, if the second value is less than the third threshold, then increment the first counter by a second number, if the second value is greater than the third threshold, then increment the second counter by the second number, the second number being strictly greater than zero. - The second number is less than the first number. - The process includes: - a calculation of a third value by subtracting a resultant value from a fifth capacitive sensor with interdigitated electrodes located in a rear area of ​​the central part of the seat, from the second value, - a comparison of the third value to a fourth threshold, if the third value is less than the fourth threshold, then increment the first counter by a third number, if the third value is greater than the fourth threshold, then increment the second counter by the third number, the third number being strictly greater than zero. - The third number is less than the second number. - The process involves comparing the value of the first counter and the value of the second counter; when the value of the first counter is greater than the value of the second counter, then a signal representative of a occupant of a first staturo-ponderal type, when the value of the first counter is less than the value of the second counter then generation of a signal representative of an occupant of a second staturo-ponderal type, the second staturo-ponderal type having a stature and a weight greater than the first staturo-ponderal type. - At least one capacitive sensor among the second capacitive sensor and the fourth capacitive sensor, has an "L" shape; and in which the second capacitive sensor and the fourth capacitive sensor are located symmetrically on either side of a central line extending in a longitudinal direction, said central line being centered with respect to the lateral edges of the central part of the seat. - The second capacitive sensor is located on a median area of ​​the seat, the second capacitive sensor being the only sensor located on the median area, the second capacitive sensor having the shape of an "I" extending along the transverse direction Y over a length at least equal to half the width of the seat. - The seat includes a sixth capacitive sensor with interdigitated electrodes, the sixth capacitive sensor being located on a front area of ​​the central part of the seat, the sixth capacitive sensor having the shape of an "I" extending along the transverse direction Y over a length at least equal to half the width of the seat. Brief description of the figures

[0005] [Fig.1] is a top perspective view of a seat of a determination system according to a first embodiment, this system allowing to implement a determination method according to a first embodiment of the invention;

[0006] [Fig.2] is a top view of a flexible support for the determination system illustrated in [Fig.1];

[0007] [Fig.3] is a flowchart representing the steps of the determination process according to the first embodiment;

[0008] [Fig.4] is a top view of a flexible support of a determination system according to a second embodiment and allowing to implement a determination process according to a second embodiment;

[0009] [Fig.5] is a top view of a flexible support of a first variant of the determination system according to the first embodiment. Detailed description of the invention

[0010] In the different figures, the same references designate identical or similar elements.

[0011] In the following description, spatial positioning indications such as up, down, superior, inferior, horizontal, vertical, etc., are given for clarity of explanation, based on the usual position of use of a seat, but are not limiting. More specifically, the orientations relating to the front and rear of the seat are relative to the usual position of use of the seat.

[0012] Longitudinal direction X means a horizontal direction extending from the front to the rear of the seat. Transverse direction Y means a horizontal direction extending from one side of the seat to the other side of the vehicle seat. Vertical direction Z means the direction perpendicular to the longitudinal direction X and the transverse direction Y.

[0013] The method for determining the height and weight type of a seat occupant makes it possible to determine the body size of a seat occupant. In particular, the method for determining a height and weight type makes it possible to select a height and weight type from among three characteristic types. These three characteristic types are a child type, an adult female type, and an adult male type. The method for determining the height and weight type of a seat occupant can, for example, be implemented by a determination system 2 according to a first embodiment illustrated in [Fig. 1]. This determination system 2 comprises a seat 4 having a seat 6 and a backrest 8 supported by the seat, a flexible support 9, six capacitive sensors with interdigitated electrodes Cl, C2, C3, C4, C5, C6 carried by the flexible support 9, and a controller 10 electrically connected to the capacitive sensors with interdigitated electrodes.

[0014] Seat 4 is for example a vehicle seat and in particular a motor vehicle seat.

[0015] The seat 6 includes a receiving face 12 intended to accommodate a seat occupant. The seat, and in particular the receiving face of the seat, includes a central part 14, a first lateral support edge 16 and a second lateral support edge 18.

[0016] For the purposes of this description, the central part 14 of the seat is said to be divided (or distributed) by two transverse lines Y1, Y2, into three zones. These three zones have the same dimensions along the longitudinal direction X. A zone adjacent to the backrest is called the "rear zone 20". A zone located on the side opposite the backrest is called the "front zone 22". The zone located between the front zone and the rear zone is called the "middle zone 24".

[0017] The lateral support edges 16, 18 are generally called "bolsters" in English. They are integral with and contiguous to the central part 14. They extend outward from the central part. They extend along the lateral sides 28, 30 of the central part of the seat.

[0018] The flexible support 9 is arranged on the seat foam or the network of threads forming the seat. The flexible support 9 is made of a plastic material such as, for example, thermoplastic polyurethane, known by the acronym TPU. The capacitive sensors with interdigitated electrodes Cl, C2, C3, C4, C5, C6 are attached to the flexible support, for example by gluing. These capacitive sensors with interdigitated electrodes are hereinafter referred to as capacitive sensors. These capacitive sensors are described in patent FR 2109436 granted to the applicant.

[0019] The flexible support 9 is fixed to the seat in such a way that the capacitive sensors are arranged at particular locations on the seat. Thus, a first capacitive sensor Cl is located on the first lateral support edge 16. Specifically, the first capacitive sensor Cl is located on a face of the first lateral support edge adjacent to the central part.

[0020] A second capacitive sensor C2 and a fourth capacitive sensor C4 are arranged on the flexible support so as to be located on the central part 14 of the seat.

[0021] In particular, in the first embodiment of the invention shown in [Fig. 1], the second capacitive sensor C2 and the fourth capacitive sensor C4 are arranged on the central area 24 of the seat. The second capacitive sensor C2 and the fourth capacitive sensor C4 have an "L" shape. One arm of this "L" shape extends along the longitudinal direction X. The other arm of this "L" shape extends along the transverse direction Y. The second capacitive sensor C2 and the fourth capacitive sensor C4 are located symmetrically on either side of a central line XI extending along a longitudinal direction X. The central line XI is centered along the transverse direction Y with respect to the lateral edges 28, 30 of the central part of the seat.

[0022] A third capacitive sensor C3 is arranged on the flexible support 9 so as to be located on the second lateral support rim 18, in particular, on a face of the second lateral support rim adjacent to the central part.

[0023] A fifth capacitive sensor C5 is arranged on the flexible support 9 so as to be located on the rear area 20 of the central part of the seat. Preferably, the fifth capacitive sensor C5 has a "T" shape. The fifth capacitive sensor C5 has a first arm extending along the transverse direction Y and a second arm extending along the longitudinal direction X. The second arm originates from the middle of the first arm. Preferably, the first arm extends along the transverse direction Y for a length at least equal to half the width of the central part 14 of the seat. In the present patent application, the width of the central part of the seat is measured along the transverse direction Y. Preferably, the first arm is centered along the transverse direction with respect to the lateral edges 28, 30 of the central part.Preferably, the second branch extends over a length less than one-third of the length of the first branch.

[0024] A sixth capacitive sensor C6 is arranged on the flexible support 9 so as to be positioned on the front area 22 of the central part of the seat. The sixth capacitive sensor C6 is shaped like an "I". The sixth capacitive sensor C6 extends along the transverse direction Y over a length at least equal to half the width of the central part of the seat.

[0025] The controller 10 includes a processor, a memory connected to the processor, a first counter 25 and a second counter 26 connected to the processor. The processor further includes a voltage source, a ground and a capacitance measuring unit.

[0026] The voltage source generates a voltage of, for example, 5 Volts.

[0027] The processor implemented by hardware may be equipped with ASICs (integrated circuits application-specific), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field-programmable gate arrays), and the like. The determination system 2 further comprises electrical wires 32 fixed to the flexible support 9, an electrical connector 34 fixed to one end of the flexible support, and wiring 36 connecting the controller 10 to the electrical connector 34. Each electrical wire 32 is connected between an electrode of a capacitive sensor and the electrical connector 34. The electrical wires 32 and the wiring 36 electrically connect one electrode of each capacitive sensor C1 to C6 to the voltage source of the controller and a second electrode of each capacitive sensor C1 to C6 to ground. The capacitance measurement unit is suitable for measuring the capacitance between the electrodes of each capacitive sensor.

[0028] According to a second embodiment illustrated in [Fig.4], the flexible support 9 of the determination system 2 comprises only a first capacitive sensor Cl intended to rest on the first lateral support edge 16, a second capacitive sensor C2 and a fourth capacitive sensor C4 intended to rest on the median area 24 of the central part of the seat, a fifth capacitive sensor resting on the rear area 20 and a sixth capacitive sensor resting on the front area 22.

[0029] According to a first variant of the first embodiment, the flexible support of the determination system 2 comprises only one capacitive sensor in its central area 24, called the second capacitive sensor. This second capacitive sensor C2 may be L-shaped and positioned on one side of the central line XL. This second capacitive sensor C2 may also be I-shaped, extending along the transverse direction Y for a length at least equal to half the width of the central part of the seat. In this case, it is centered along the transverse direction with respect to the lateral edges 28, 30 of the central part 14. This The first variant is illustrated in [Fig. 5] on a flexible substrate according to the first embodiment. This first variant can also be applied to a flexible substrate according to the second embodiment.

[0030] According to a second embodiment of the first, the fifth capacitive sensor C5, located on the rear area 20, has an "I" shape instead of a "T" shape. The fifth capacitive sensor C5 is centered in the transverse direction with respect to the lateral edges 28, 30 of the central part 14. The fifth capacitive sensor C5 extends in the transverse direction Y over a length at least equal to half the width of the central part of the seat. This second embodiment can also be applied to a flexible support according to the second embodiment.

[0031] According to a third variant of the first embodiment, the determination system 2 does not include the sixth capacitive sensor C6. No capacitive sensor is arranged on the flexible support so as to be located in the front area 22 of the central part. This third variant can also be applied to a flexible support according to the second embodiment.

[0032] According to a third embodiment, the flexible support of the determination system 2 comprises only the first capacitive sensor C1 arranged to rest on the first lateral support edge 16 and a second capacitive sensor C2 arranged to rest on the median area 24 of the central part of the seat. This second capacitive sensor C2 may be L-shaped and arranged on one side of the central line XL. This second capacitive sensor C2 may also be I-shaped, extending along the transverse direction Y for a length at least equal to half the width of the central part of the seat. In this case, it is centered along the transverse direction with respect to the lateral edges 28, 30 of the central part 14.

[0033] According to a variant of the first, second and third embodiments, the capacitive sensors Cl to C6 are arranged directly on the foam or the fiber tangle forming the seat. In this case, the determination system does not include a flexible support.

[0034] The method for determining the height and weight of a seat occupant according to the first embodiment is implemented by the determination system illustrated in Figures 1 and 2. This determination method begins with a triggering step 40 of a measurement phase of capacitance values ​​at the electrodes of the capacitive sensors C1 to C6 by the measuring unit. The measurement phase lasts for the entire duration of the detection process. The measurement phase is divided into measurement periods. A measurement period has a duration of between 0.6 and 1 millisecond. During each measurement period, the processor's measuring unit The capacitance values ​​of capacitive sensors Cl to C6 are measured at a frequency, for example, of 100 milliseconds. The process then continues with the steps described below.

[0035] During a processing step 42, the capacitance values ​​measured during each measurement period are processed in order to determine the resulting capacitance values ​​of these capacitive sensors.

[0036] In the present description, a resulting capacitance value of a given capacitive sensor may, for example, be an average capacitance value calculated from the capacitance values ​​measured over a period for that capacitive sensor.

[0037] A resulting capacitance value of a given capacitive sensor can also be a median value between a maximum capacitance value and a minimum capacitance value measured over a period for that capacitive sensor.

[0038] During a step 44, a first DI data representative of the pressure exerted on the seat is calculated from a resultant capacitance value Cri of the first capacitive sensor Cl, a resultant capacitance value Cr2 of the second capacitive sensor C2, a resultant capacitance value Cr3 of the third capacitive sensor C3, a resultant capacitance value Cr4 of the fourth capacitive sensor C4, a resultant capacitance value Cr5 of the fifth capacitive sensor C5 and a resultant capacitance value Cr6 of the sixth capacitive sensor C6.

[0039] In particular, the calculation of the first data DI includes the calculation of a sum weighted by a weighting coefficient, of the resulting capacitance values ​​of the capacitive sensors resting on the seat namely on the central part of the seat and on the lateral support edges 16, 18. These capacitive sensors are the capacitive sensors Cl to C6 in the first embodiment of the invention.

[0040] Preferably, the weighting coefficient comprises a ratio between a non-zero natural number and an average of a resulting capacitance value Cri of the first capacitive sensor C1 and a resulting capacitance value Cr3 of the third capacitive sensor C3. Preferably, the non-zero natural number is equal to one. Thus, when the determination system is the system illustrated in [Fig. 1], the first DI datum is calculated from the following formula: Crt+Cr2+Cr3rCr4+<::r5+Cr6 • average (Cr 1+Cr3) in which Cr1, Cr2, Cr3, Cr4, Cr5, Cr6 are the resulting values ​​of the capacitive sensors Cl to C6.

[0041] The value -------!------- is a weighting coefficient. This coefficient of average (Cr 1+Cr3) weighting is applied to each resulting capacitance value from each capacitive sensor.

[0042] In a step 46, a second datum D2 is calculated from the resulting capacitance value Cri of the first capacitive sensor Cl and the resulting capacitance value Cr3 of the third capacitive sensor C3. The second datum D2 is representative of the pressure exerted on the first lateral support edge 16 of the seat and the pressure exerted on the second lateral support edge 18. In particular, the second datum D2 comprises the sum of a resulting capacitance value of the first capacitive sensor Cl and a resulting capacitance value of the third capacitive sensor C3.

[0043] In other words: D2 = Cri + Cr3

[0044] in which Cri and Cr3 are the resulting values ​​of the first capacitive sensor Cl and the third capacitive sensor C3.

[0045] During a step 48, a first value V1 is calculated as a function of the first data DI and the second data D2. In particular, the first value V1 is the sum of the first data DI and the second data D2.

[0046] Thus y [ = + Q1 + average (Crl+Cr3)

[0047] In step 50, the first VI value is compared to a first SI threshold. The first SI threshold is between 2 and 4 picofarads. Preferably, the first SI threshold is equal to 3 picofarads. When the first VI value is less than the first threshold, a signal representative of a child-type occupant is generated and transmitted by the controller in step 51. For example, a child-type occupant has a weight of approximately between 13 and 19 kilograms and a height of approximately between 88 and 125 centimeters. Then, the process returns to step 42 to process the capacity values ​​of the next period.

[0048] During a step 52, the first counter 25 and the second counter 26 are initialized. During a step 54, the second data D2 is compared to a second threshold S2, if the second data D2 is less than the second threshold then the first counter 25 is incremented by a first number. If the second value D2 is greater than the second threshold S2, then the second counter 26 is incremented by the first number. The first number is strictly greater than zero. For example, the first number is equal to 2. The second threshold S2 is between 6 and 8 picofarads. Preferably, the second threshold S2 is equal to 7 picofarads.

[0049] During a step 56, a second value V2 is calculated as a function of the resulting value Cr2 of the second capacitive sensor C2 and the resulting value Cr4 of the fourth capacitive sensor C4.

[0050] Preferably, the second value V2 is equal to the sum of the resulting value Cr2 of the second capacitive sensor and the resulting value Cr4 of the fourth capacitive sensor.

[0051] V2 = Cr2 + Cr4 in which Cr2 and Cr4 are the resulting values ​​of the second capacitive sensor C2 and the fourth capacitive sensor C4. In step 58, the second value V2 is compared to a third threshold S3. If the second value V2 is less than the third threshold S3, then the first counter 25 is incremented by a second number. If the second value V2 is greater than the third threshold S3, then the second counter 26 is incremented by the second number. The second number is strictly greater than zero. Preferably, the second number is less than the first number. For example, the second number could be 1.5. The third threshold S3 is between 2 picofarads and 4 picofarads. Preferably, the third threshold S3 is equal to 3 picofarads.

[0052] During a step 60, a third value V3 is calculated by subtracting the second value V2 from the resulting value of the fifth capacitive sensor.

[0053] V3 = Cr5 - (Cr2 + Cr4)

[0054] Arguing that Cr2, Cr4, and Cr5 are the resulting values ​​of the second capacitive sensor C2, the fourth capacitive sensor C4, and the fifth capacitive sensor C5. In a step 62, the third value V3 is compared to a fourth threshold S4. If the third value V3 is less than the fourth threshold S4, then the first counter 25 is incremented by a third number. If the third value V3 is greater than the fourth threshold S4, then the second counter 26 is incremented by the third number. The third number is strictly greater than zero. The third number is less than the second number. The third number is, for example, equal to 1. The fourth threshold S4 is between 9 picofarads and 11 picofarads. Preferably, the fourth threshold S4 is equal to 10 picofarads.

[0055] During a step 64, the value of the first counter 25 is compared to the value of the second counter 26. When the value of the first counter 25 is greater than the value of the second counter, a signal representing an occupant of a first height-weight type is generated and transmitted by the controller. When the value of the first counter 25 is less than the value of the second counter 26, a signal representing an occupant of a second height-weight type is generated and transmitted. The second height-weight type has a greater height and weight than the first height-weight type.

[0056] The first height and weight type corresponds to a type known as an adult female. These individuals correspond to the 5th female percentile of the shortest and / or thinnest individuals in descriptive statistics, and in particular according to the female-specific curve of the Fisher-Snedecor distribution. These individuals have a weight between approximately between 46 kilograms and 52 kilograms and / or a height approximately between 139 centimeters and 160 centimeters.

[0057] The second height and weight type corresponds to what is called an adult male type. It corresponds to the 50th percentiles of the tallest and heaviest individuals in descriptive statistics, and in particular according to the curve relating to men in the Fisher-Snedecor distribution. These individuals have a weight of approximately between 76 kilograms and 81 kilograms and / or a height of approximately between 172 centimeters and 182 centimeters.

[0058] The determination method makes it possible to discriminate between different types of seat occupant in order to know whether or not the airbag should be triggered and possibly to know the quantity of air needed to inflate the airbag.

[0059] The determination method according to a second embodiment can be implemented using the determination system according to the second embodiment shown in [Fig. 4]. It is identical to the method according to the first embodiment except that:

[0060] - During step 44, the calculation of the first DI data includes the calculation of a sum weighted by a weighting coefficient, of the resulting capacitance values ​​of the capacitive sensors resting on the base namely the capacitive sensors C1,C2, C4 to C6.

[0061] Preferably, the weighting coefficient comprises a ratio between a non-zero natural number and a resulting capacitance value Cri of the first capacitive sensor CL. Thus, when the determination system is the system illustrated in [Fig. 4], the first data DI is calculated from the following formula: y» 4 Cr 1+Cr2+C .r4+(^r5+(..r6 • =m----- ' in which Cr1, Cr2, Cr4, Cr5, Cr6 are the resulting values ​​of the capacitive sensors Cl2, C4 to C6.

[0062] The weighting coefficient is here equal to .

[0063] - During step 46, the second data point D2 is calculated from the value of The resulting capacitance Cri of the first capacitive sensor CL. The second data point D2 is solely representative of the pressure exerted on the first lateral support edge 14 of the seat. In particular, the second data point D2 is equal to the resulting capacitance value of the first capacitive sensor CL.

[0064] In other words: D2 = Cr 1

[0065] in which Cri is the resulting value of the first capacitive sensor CL

[0066] - Furthermore, the value of the first threshold SI and the value of the second threshold S2 is different when there is only one sensor on a lateral support edge.

[0067] A determination method according to a third embodiment can be implemented using the determination system according to the first variant of the first embodiment shown in [Fig. 5]. It is identical to the method according to the first embodiment except that:

[0068] - During step 44, the first DI data point is calculated from the formula next: p _ Cr l+Cr2H< >4+Cr5+Cr6 average (Cr1+Cr3)

[0069] in which Cri, Cr2, Cr3, Cr5, Cr6 are the resulting values ​​of the capacitive sensors Cl to C3, C5 and C6.

[0070] - During step 56, the second value V2 is calculated based on the value resultant Cr2 of the second capacitive sensor C2 located on a median area of ​​the central part of the seat.

[0071] Preferably, the second value V2 is equal to the resulting value Cr2 of the second capacitive sensor.

[0072] V2 = Cr2 in which Cr2 is the resulting value of the second capacitive sensor C2.

[0073] - During step 60, the third value V3 is calculated by subtracting the second value V2 to the resulting value of the fifth capacitive sensor.

[0074] V3 = Cr5 - Cr2

[0075] Where Cr2 is the resulting capacitance value of the second capacitive sensor, and Cr5 is the resulting capacitance value of the fifth capacitive sensor C5.

[0076] In addition, the value of the first threshold S1, the value of the third threshold S3 and the value of the fourth threshold S4 are adapted to the fact that there is only one sensor of a different shape in this embodiment.

[0077] In the present application, the term “I” shape means a rectilinear shape.

Claims

Demands

1. Method for determining the staturo-ponderal type of an occupant of a seat, in particular of a vehicle seat (4); the seat comprising a seat (6), the seat comprising a central part (14) and a first lateral support edge (16);The method comprises: - a calculation (44) of a first datum (D1) representative of the pressure exerted on the seat from the resulting capacitance value of a first capacitive sensor (C1) with interdigitated electrodes located on the first lateral support edge (16) and at least one resulting capacitance value of a second capacitive sensor (C2) with interdigitated electrodes located on the central part (14) of the seat, - a calculation (46) of a second datum (D2) representative of the pressure exerted on the first lateral support edge (16) of the seat from the resulting capacitance value of the first capacitive sensor (C1), - a calculation (48) of a first value (VI) as a function of the first datum and the second datum, - a comparison (50) of the first value (VI) to a first threshold (SI), when the first value is less than the first threshold, generation of a signal representative of a child-type occupant;

2. Method of determination according to claim 1, wherein the calculation (48) of the first value (VI) comprises a sum of the first data (D1) and the second data (D2).

3. Method of determination according to any one of claims 1 and 2, wherein the calculation (44) of the first data (Dl) includes the calculation of a sum weighted by a weighting coefficient, of the resulting capacitance values ​​of the capacitive sensors located on the base.

4. A method for determining according to any one of claims 1 to 3, wherein the seat (4) comprises a second lateral support rim (18), and wherein the first datum (Dl) is calculated from the resulting capacitance value of the first capacitive sensor (Cl), the resulting capacitance value of at least a second capacitive sensor (C2), and a resulting capacitance value of a third capacitive sensor with interdigitated electrodes located on the second lateral support edge (18) of the seat; the second data (D2) being calculated from the resulting capacitance value of the first capacitive sensor (Cl) and the resulting capacitance value of the third capacitive sensor (C3); the second data being representative of the pressure exerted on the first lateral support edge (16) and on the second lateral support edge (18).

5. Method of determination according to claim 3, wherein the weighting coefficient comprises a ratio between a non-zero natural number and a value representative of the pressure exerted on at least the first lateral rim (16).

6. Method of determination according to the combination of claims 3 and 4, wherein the weighting coefficient comprises a ratio between a non-zero natural number and an average of a resultant capacitance value of the first capacitive sensor (Cl) and a resultant capacitance value of the third capacitive sensor (C3).

7. A method of determination according to the combination of claims 3 and 4, wherein the second data (D2) comprises the sum of a resulting capacitance value from the first capacitive sensor (Cl) and a resulting capacitance value from the third capacitive sensor (C3).

8. Method of determination according to any one of claims 1 to 3, wherein the second data (D2) is the resulting capacitance value of the first capacitive sensor (Cl).

9. A method of determination according to any one of claims 1 to 8, comprising: - an initialization (52) of a first counter (25) and a second counter (26), - a comparison of the second data (D2) to a second threshold (S2), if the second data (D2) is less than the second threshold (S2) then increment the first counter (25) by a first number, if the second data (D2) is greater than the second threshold (S2) then increment the second counter (26) by said first number; said first number being strictly greater than zero.

10. A method for determining according to claim 9, wherein the method comprises: - a calculation (56) of a second value (V2) as a function of a resultant value from the second capacitive sensor (C2) and a resultant value of a fourth capacitive sensor (C4) with interdigitated electrodes located on a median area (24) of the central part of the seat, the second capacitive sensor (C2) being located in a median area (24) of the central part of the seat, - a comparison (58) of the second value (V2) to a third threshold (S3), if the second value (V2) is less than the third threshold (S3), then increment the first counter (25) by a second number, if the second value is greater than the third threshold (S3), then increment the second counter (26) by the second number, the second number being strictly greater than zero.

11. A method of determination according to claim 9, wherein the method comprises: - a definition of a second value (V2) equal to a resultant value from at least a second capacitive sensor, the second capacitive sensor (C2) being located in a median area (24) of the central part of the seat; - a comparison of the second value (V2) to a third threshold (S3), if the second value (V2) is less than the third threshold (S3), then increment the first counter (25) by a second number, if the second value is greater than the third threshold (S3), then increment the second counter (26) by the second number, the second number being strictly greater than zero.

12. A method of determination according to any one of claims 10 and 11, wherein the second number is less than the first number.

13. A method for determining according to any one of claims 10 to 12, wherein the method comprises: - a calculation (60) of a third value (V3) by subtracting a resultant value from a fifth capacitive sensor (C5) with interdigitated electrodes located in a rear area (20) of the central part of the seat, from the second value (V2), - a comparison (62) of the third value (V3) to a fourth threshold (S4), if the third value (V3) is less than the fourth threshold (S4), then increment the first counter (25) by a third number, if the third value (V3) is greater than the fourth threshold (S4), then increment the second counter (26) by the third number, the third number being strictly greater than zero.

14. Method of determination according to claim 13, wherein the third number is less than the second number.

15. A method for determining according to any one of claims 9 to 14, comprising a comparison (64) of the value of the first counter (25) and the value of the second counter (26), where the value of the first counter is greater than the value of the second counter then generation of a signal representative of an occupant of a first staturo-ponderal type, where the value of the first counter (25) is less than the value of the second counter (26) then generation of a signal representative of an occupant of a second staturo-ponderal type, the second staturo-ponderal type having a stature and a weight greater than the first staturo-ponderal type.

16. A method of determination according to any one of claims 1 to 10 and 12 to 15, wherein at least one capacitive sensor among the second capacitive sensor (C2) and the fourth capacitive sensor (C4) has an "L" shape; and wherein the second capacitive sensor (C2) and the fourth capacitive sensor (C4) are located symmetrically on either side of a central line (XI) extending along a longitudinal direction X, said central line (XI) being centered with respect to the lateral edges (28, 30) of the central part of the seat.

17. A method of determination according to any one of claims 1 to 9 and 11 to 15, wherein the second capacitive sensor (C2) is located on a median area (24) of the seat, the second capacitive sensor (C2) being the only sensor located on the median area (24), the second capacitive sensor (C2) having the shape of an “I” extending along the transverse direction Y over a length at least equal to half the width of the seat.

18. A method of determination according to any one of claims 1 to 17, wherein the seat (6) comprises a sixth capacitive sensor (C6) with interdigitated electrodes, the sixth capacitive sensor (C6) being located on a front area (22) of the central part of the seat, the sixth capacitive sensor (C6) having the shape of an “I” extending along the transverse direction Y over a length at least equal to half the width of the seat.

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