Method for detecting an inappropriate posture of an occupant seated in a vehicle seat

Abstract

The invention is a method for detecting an inappropriate posture of an occupant seated in a vehicle seat, the method comprising the following steps: - after a first defined period following detection of the presence of an occupant in the seat, - for each pressure sensor of the detection system: a) determine (106) a characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a first period, b) determine (108) an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine (114, 116, 118, 120, 122) the absence of pressure on an area based on the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period, - generate (124) a warning signal when the absence of pressure has been determined in at least one area. Figure to be published with the abbreviation: Figure 3

Description

Title of the invention: Method for detecting an inappropriate posture of an occupant seated in a vehicle seat. Technical field of the invention

[0001] The invention relates to a method for detecting an inappropriate posture of an occupant seated on a seat of a vehicle, in particular a motor vehicle.

[0002] Presentation of the invention

[0003] It would be desirable to propose an inappropriate posture detection system that informs the seat occupant that he is either in an unsafe position in relation to his driving or in an uncomfortable position which may in the long term generate fatigue or muscular or joint pain in the back or neck.

[0004] The object of the present invention is to propose a reliable and robust method for detecting inappropriate posture. Summary of the invention

[0005] The present invention relates to a method for detecting an inappropriate posture of an occupant seated on a seat of a vehicle, in particular a motor vehicle; the seat having a seat and a backrest articulated to the seat, the backrest comprising two lateral edges, an upper edge and a lower edge adjacent to the seat; a first vertical central plane extending between and halfway between the two lateral edges, a first horizontal central plane extending between and halfway between the upper edge and the lower edge;the method being implemented by a detection system comprising a processor, at least a first pressure sensor arranged on a first zone located on one side of the first vertical central plane and above the first horizontal central plane, a second pressure sensor arranged on a second zone located on the other side of the first vertical central plane and above the first horizontal central plane, a third pressure sensor arranged on a third zone located on said side of the first vertical central plane and below the first horizontal central plane, a fourth pressure sensor arranged on a fourth zone located on said other side of the first vertical central plane and below the first horizontal central plane; the method comprising a step of triggering a measurement phase comprising periods of time during which capacitive values ​​are measured by the first, second, third and fourth pressure sensors;the process further comprising the following steps implemented by the processor during the measurement phase: ; - upon detection of the presence of an occupant on the seat, activate a timer to signal the end of a first defined period; - after the first defined period, consider each pressure sensor among the first, second, third, and fourth pressure sensors,

[0006] - for each pressure sensor considered: a) determine a characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a first period, b) determine an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine the presence or absence of support on an area based on the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate a warning signal when a lack of support has been determined in at least one of the areas considered.

[0007] 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 step of determining the presence or absence of support in an area includes the following steps: (i) determine a subsequent characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a subsequent period, (ii) compare the following characteristic value to said permissible variation range defined for the sensor in question; iii) determine the absence of a support on the area considered if the following characteristic value is not within the permissible variation range defined for said sensor considered or determine the presence of a support when the following characteristic value is within the permissible variation range defined for said sensor considered.

[0008] -The method further includes a step of repeating steps i) to iii) for a second defined duration and in which the step of generating a warning signal is implemented only if an absence of a support is determined continuously for a duration at least equal to the second defined duration. - If the presence of a support has been determined on the first zone and on the second zone and the absence of a support has been determined on the third zone and on the fourth zone, then the generated warning signal is representative of a pelvis position in front of the seat occupant. - If an absence of support has been determined on the first zone and the third zone, and a presence of support has been determined on the second zone and the fourth zone, then the generated warning signal is representative of a trunk position rotated to the side. - If an absence of support has been determined on the first zone and on the second zone and a presence of support has been determined on the third zone and on the fourth zone then the generated warning signal is representative of a forward leaning position of the seat occupant.

[0009] - the seat 4 comprises a front edge and a rear edge, a vertical transverse plane being defined at the midpoint between the front edge of the seat and the rear edge of the seat, The detection device comprises at least one first front pressure sensor disposed on a front area of ​​the seat located in front of the vertical transverse plane, and one first rear pressure sensor disposed on a rear area of ​​the seat located behind the vertical transverse plane; the method comprising the following steps: - consider each pressure sensor, including the first front pressure sensor and the rear pressure sensor, for each sensor considered: a) determine a characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a first period, b) determine an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine the presence or absence of support on an area based on the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate a warning signal when a lack of support has been determined in the rear area, the generated warning signal being representative of a pelvis position in front of the seat occupant.

[0010] The seat comprises two lateral edges, a second central vertical plane being defined midway between the two lateral edges of the seat, The front area comprises a first front seating area arranged on one side of the second central vertical plane, and a second front seating area arranged on the other side of the second central vertical plane. The rear area comprises a first rear seating area located on one side of the second central vertical plane, and a second rear seating area located on the other side of the second central vertical plane. the detection device includes a second front pressure sensor arranged In the second front zone, the first front pressure sensor being located in the first front zone, the detection device further comprises a second rear pressure sensor disposed in the second rear zone, the first rear pressure sensor being located in the first rear zone, the method comprising the following steps: - consider each pressure sensor from among the second front pressure sensor (34) and the second rear pressure sensor for each sensor considered: a) determine a characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a first period, b) determine an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine the presence or absence of support on an area based on the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate a warning signal when a lack of support has been determined on the first front zone or on the second front zone, the generated warning signal being representative of a position of one leg crossed over the other leg of the seat occupant.

[0011] The invention also relates in A): a method for detecting an inappropriate posture of an occupant seated on a seat in a vehicle, in particular a motor vehicle; the seat having a seat and a backrest articulated to the seat, the backrest comprising two lateral edges, a first central vertical plane extending between and midway between the two lateral edges; the method being implemented by a detection system comprising a processor, at least one first pressure sensor arranged on a first area located on one side of the first central vertical plane, and a second pressure sensor arranged on a second area located on the other side of the first central vertical plane; the method comprising a step of triggering a measurement phase comprising periods of time during which capacitive values ​​are measured by the first and second pressure sensors;the process further comprising the following steps implemented by the processor during the measurement phase: ; - upon detection of the presence of an occupant on the seat, activate a timer to signal the end of a first defined period; - after the first defined period, consider each pressure sensor, starting with the first pressure sensor and the second pressure sensor, for each sensor considered: a) determine a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine an permissible variation range defined for the sensor considered as a function of said characteristic value, c) determine the presence or absence of support on an area based on the permissible variation range defined for the sensor considered and the capacitive values ​​measured during a subsequent period by the pressure sensor considered arranged in said area, - generate a warning signal when a lack of support has been determined in at least one zone between the first zone and the second zone (Z2).

[0012] The invention also relates in B): a method for detecting an inappropriate posture of an occupant seated in a vehicle seat, in particular a motor vehicle; the seat having a seat and a backrest articulated to the seat, the backrest comprising an upper edge and a lower edge adjacent to the seat; a horizontal central plane extending midway between the upper edge and the lower edge; the method being implemented by a detection system comprising a processor, at least one first pressure sensor arranged on a first area located above the horizontal central plane, and a second pressure sensor arranged on a second area located below the horizontal central plane; the method comprising a step of triggering a measurement phase comprising periods of time during which capacitive values ​​are measured by the first and second pressure sensors;the process further comprising the following steps implemented by the processor during the measurement phase: ; - upon detection of the presence of an occupant on the seat, activate a timer to signal the end of a first defined period; - after the first defined duration, consider each pressure sensor, including the first pressure sensor and the second pressure sensor. for each sensor considered: a) determine a characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a first period, b) determine an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine the presence or absence of support on an area based on the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate a warning signal when a lack of support has been determined in at least one zone between the first zone and the second zone. According to one embodiment, in the detection method according to (A) and (B), the step of determining the presence or absence of a support on an area comprises the following steps: i) determine a subsequent characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a subsequent period, ii) compare the subsequent characteristic value to said permissible range of variation defined for the sensor in question; iii) determine the absence of a support on the area considered if the following characteristic value is not within the permissible variation range defined for said sensor considered or determine the presence of a support when the following characteristic value is within the permissible variation range defined for said sensor considered.

[0013] - According to one embodiment, the detection method according to A) and B) comprises in in addition to a step of repeating steps i) to iii) for a second defined duration and in which the step of generating a warning signal is implemented only if an absence or presence of a support is determined continuously for a duration greater than the second defined duration.

[0014] In the detection method according to A), if an absence of support has been determined in the first zone and a presence of support has been determined in the second zone then the generated warning signal is representative of a trunk position rotated to the side.

[0015] According to one embodiment, in the detection method according to B), if an absence of support has been determined in the first zone and in the second zone then the generated warning signal is representative of a forward-leaning position of the seat occupant.

[0016] According to one embodiment, in the detection method according to A) and B), the seat comprises a front edge and a rear edge, a vertical transverse plane being defined between and at the midpoint of the front edge of the seat and the rear edge of the seat, The detection device comprises at least one first front pressure sensor disposed on a front area of ​​the seat located in front of the vertical transverse plane, and one first rear pressure sensor disposed on a rear area of ​​the seat located behind the vertical transverse plane, the method comprising the following steps: - consider each pressure sensor, including the first front pressure sensor and the first rear pressure sensor, - for each sensor considered: a) determine a characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a first period, b) determine an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine the presence or absence of support on an area based on the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate a warning signal when a lack of support has been determined in the rear area, the generated warning signal being representative of a pelvis position in front of the seat occupant.

[0017] According to one embodiment, in the detection method according to A) and B), the seat comprises two lateral edges, a second vertical central plane being defined midway between the two lateral edges of the seat, The front area comprises a first front seating area arranged on one side of the second central vertical plane and a second front seating area arranged on the other side of the second central vertical plane. The rear area comprises a first rear seating area located on one side of the second central vertical plane, and a second rear seating area located on the other side of the second central vertical plane. The detection device includes a second front pressure sensor located in the second front zone, the first front pressure sensor being located in the first front zone. the detection device (further includes a second rear pressure sensor located on the second rear zone, the first rear pressure sensor being located on the first rear zone, The process involves the following steps: - consider each pressure sensor, including the second front pressure sensor and the second rear pressure sensor, - for each sensor considered: a) determine a characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a first period, b) determine an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine the presence or absence of support on an area based on the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate a warning signal when a lack of support has been determined on the first front zone or on the second front zone, the generated warning signal being representative of a position of one leg crossed over the other leg of the seat occupant. Brief description of the figures

[0018] [Fig.1] is a schematic perspective view of a seat and a detection system according to a first embodiment of the invention;

[0019] [Fig.2] is a schematic perspective view of the seat and part of a detection system that can be added to the detection system illustrated in [Fig.1];

[0020] [Fig.3] is a diagram representing the steps of the detection process according to the invention;

[0021] [Fig.4] is a schematic perspective view of a seat and a detection system according to a second embodiment;

[0022] [Fig.5] is a schematic perspective view of a seat and a detection system according to a third embodiment;

[0023] [Fig.6] is a schematic perspective view of a seat and a detection system, a fourth embodiment. Detailed description of the invention

[0024] In this patent application, identical or similar elements bear the same references and will not be described a second time.

[0025] In this application, the terms "upper", "lower", "front", "rear", "front", "rear" are to be interpreted with regard to the usual position of a seat in a motor vehicle. The front of a vehicle seat corresponds to the front of the vehicle when considering the normal direction of travel of the vehicle.

[0026] In this application, the longitudinal direction X means a horizontal direction extending from the front to the rear of the vehicle seat. The transverse direction Y means a horizontal direction extending from one side of the seat to the other side of the seat. The vertical direction Z means the direction perpendicular to the longitudinal direction X and the transverse direction Y.

[0027] A motor vehicle seat 2 comprises a seat 4, a backrest 6 articulated to the seat 4.

[0028] With reference to [Fig.1], the backrest 6 comprises two lateral edges 8, 10, an upper edge 12 and a lower edge 14 adjacent to the seat. For the purposes of this patent application, a first vertical central plane (X1,Z1) is defined extending between and halfway between the two lateral edges 8, 10, and a first horizontal central plane (X,Y) is defined extending between and halfway between the upper edge 12 and the lower edge 14 of the file. These plans allow us to define four zones on the file. In particular, a first zone Z1 is located on one side of the first vertical central plane (XI,Z1) and above the first horizontal central plane (X,Y). A second zone Z2 is located on the other side of the first vertical central plane (XI,Z1) and above the first horizontal central plane (X,Y).

[0029] A third zone Z3 is located on said side of the first vertical central plane (X1,Z1) and below the first horizontal central plane (X,Y). A fourth zone Z4 is located on said other side of the first vertical central plane (X1,Z1) and below the first horizontal central plane (X,Y).

[0030] The detection method according to a first embodiment is implemented by a detection system 15 according to a first embodiment comprising a processor 16, and at least four pressure sensors arranged on the backrest.

[0031] With reference to [Fig.1], the sensors located on the backrest include a first pressure sensor 18 arranged on the first zone Z1, a second pressure sensor 20 arranged on the second zone Z2, a third pressure sensor 22 arranged on a third zone Z3, a fourth pressure sensor 24 arranged on the fourth zone Z4 of the backrest.

[0032] According to an advantageous and in no way limiting variant, the detection method according to the first embodiment is implemented by a detection system 15 further comprising four pressure sensors on the seat.

[0033] In particular, with reference to [Fig.2], the seat 4 has a front edge 26, a rear edge 28 and two lateral edges 33, 36.

[0034] For the purposes of this patent application, a vertical transverse plane (Y,Z) is defined, located midway between the front edge 26 of the seat and the rear edge 28 of the seat, and a second central vertical plane (X2, Z2) is defined, located midway between the two lateral edges 33, 36 of the seat.

[0035] The seat 4 comprises a front zone ZA located in front of the vertical transverse plane (Y,Z), and a rear zone ZR located behind the vertical transverse plane (Y,Z). In particular, the seat comprises a first front zone ZA1 of the seat arranged on one side of the second vertical central plane (Y,Z), and a second front zone ZA2 of the seat arranged on the other side of the second vertical central plane (Y,Z). Similarly, the rear zone ZR of the seat 4 comprises a first rear zone ZR1 located on one side of the second vertical central plane (Y,Z), and a second rear zone ZR2 located on the other side of the second vertical central plane (Y,Z).

[0036] With reference to [Fig. 2], the sensors located on the seat comprise a first front pressure sensor 30 disposed on the first front zone ZA1 of the seat, a second front pressure sensor 34 disposed on the second front zone ZA2, a first rear pressure sensor 32 located on the first rear zone ZR1, and a second rear pressure sensor 37 located on the second rear zone ZR2.

[0037] Pressure sensors are, for example, capacitive sensors with coplanar interdigitated electrodes as described in patent application published under number FR 3 126 776.

[0038] With reference to [Fig. 3], the method for detecting an inappropriate posture begins with a trigger step 100 of a measurement phase. During the measurement phase, measurements are taken at regular time intervals of capacitance values ​​generated by the pressure sensors 18 to 24. The measurement phase includes time periods during which several measurements are taken. The measurement phase is implemented continuously throughout all steps of the process. Steps 114 to 124 are repeated with the new capacitance values ​​measured during the measurement phase.

[0039] The method then includes a step 102 for detecting the presence of an occupant on the seat. This step can be performed using capacitance values ​​measured according to a known method or by another means such as a camera and image recognition system. After detecting the presence of an occupant on the seat, a clock is triggered during a step 104. The clock is configured to signal the end of a first defined duration DI.

[0040] Then, after the first defined duration, each pressure sensor among the first, second, third, fourth pressure sensors, is considered.

[0041] For each pressure sensor considered, steps 106 to 122 are implemented.

[0042] During step 106, a characteristic value representing the capacitive values ​​generated by each pressure sensor considered is determined. This characteristic value is representative of the capacitive values ​​measured during a first period. The first period is the first period following the first defined duration DI. This characteristic value is, for example, an average value of the capacitive values ​​measured during the first period. Alternatively, the characteristic value is a median value of the capacitive values ​​measured during the first period. In step 108, a defined permissible variation range for the sensor in question is determined. This permissible variation range is determined based on the characteristic value. For example, the lower value of the permissible variation range is equal to the characteristic value less 15% of the characteristic value, and the upper value of the permissible variation range is equal to the characteristic value plus 15% of the characteristic value.

[0043] According to another example, the lower value of the allowable variation range is equal to the characteristic value less 20% of the characteristic value and the upper value of the allowable variation range is equal to the characteristic value plus 20 % of the characteristic value. During a step 110, the permissible range of variation defined during step 108 is stored in the memory of processor 16.

[0044] During step 112, the process returns to step 106, another pressure sensor is considered, and steps 106 to 110 are implemented for this other sensor. Steps 106 to 110 are thus implemented for each pressure sensor. During steps 114 to 122, each zone is considered, and the presence or absence of support is determined in each zone based on the capacitive values ​​measured by the pressure sensors arranged in those zones. The zones considered are the first zone Z1, the second zone Z2, the third zone, and the fourth zone Z4 of the backrest, as well as the first front zone ZA1, the second front zone ZA2, the first rear zone ZR1, and the second rear zone ZR2 of the seat.

[0045] During a step 114, a subsequent characteristic value is determined from the capacitive values ​​generated during a subsequent period by the pressure sensor in question. This subsequent characteristic value is representative of the capacitive values ​​measured during a subsequent period. In this patent application, the term "subsequent period" refers to the period immediately following the first period, as well as all subsequent periods. Step 114 will be repeated at each new period for the entire duration of the measurement phase. This subsequent characteristic value is, for example, an average value of the capacitive values ​​measured during a subsequent period. Alternatively, the subsequent characteristic value is a median value of the capacitive values ​​measured during a subsequent period.

[0046] During a step 116, the following characteristic value is compared to the permissible variation range defined for the sensor considered and stored in the processor memory. When the following characteristic value is within the permissible range of variation, the presence of a support in the area under consideration is determined during a step 118. When the following characteristic value is outside the permissible range of variation, the absence of a support in the area under consideration is determined during a step 118. Steps 114 to 118 are repeated for all pressure sensors during a step 120.

[0047] Preferably, the method includes a step 122 in which steps 114 to 118 are repeated based on the capacitive values ​​generated by the pressure sensors during subsequent periods. These steps 114 to 118 are repeated several times over a period at least equal to the second defined period D2. And steps 123 and 124 are only implemented if a lack of support has been determined during the second defined period. Then, during step 123, the set of support presence and absence states is analyzed to determine if the seat occupant has an unsuitable position on the seat.

[0048] During a step 124, a warning signal is generated when a lack of support has been determined in at least one area among the areas considered.

[0049] In particular, if the presence of a support has been determined in the first zone ZI and in the second zone Z2 and the absence of a support has been determined in the third zone Z3 and in the fourth zone Z4, then the generated warning signal is representative of a pelvis position in front of the seat occupant.

[0050] When the seat has four sensors on the seat in addition to the four sensors on the backrest, the warning signal representing a forward pelvic position of the seat occupant is confirmed by a determination of the absence of support on the first rear zone ZR1 from the capacitive values ​​measured by the first rear pressure sensor 32 and on the second rear zone ZR2 from the capacitive values ​​measured by the second rear pressure sensor 37.

[0051] When an absence of support has been determined on the first zone ZI and on the third zone Z3, and a presence of support has been determined on the second zone Z2 and on the fourth zone Z4, then the generated warning signal is representative of a trunk position rotated to the side.

[0052] When an absence of support has been determined on the second zone Z2 and on the fourth zone Z4, and a presence of support has been determined on the first zone ZI and on the third zone Z3, then the generated warning signal is also representative of a trunk position rotated to the side.

[0053] When an absence of support has been determined on the first zone ZI and on the second zone Z2 and a presence of support has been determined on the third zone Z3 and in the fourth zone Z4 then the generated warning signal is representative of a forward leaning position of the seat occupant.

[0054] When an absence of support has been determined on the first zone before ZA1 or on the second zone before ZA2, the generated warning signal is representative of a position of one leg crossed over the other leg of the seat occupant.

[0055] In step 126, the warning signal may be transmitted to a display device to show an image corresponding to the type of inappropriate posture detected. Alternatively, the warning signal is transmitted to an audible system emitting an audible alert or to a voice system capable of selecting a voice message corresponding to the type of inappropriate posture detected.

[0056] Figure 4 represents a detection system according to a second embodiment capable of implementing the detection method according to the invention. In this second embodiment, the detection system 15 comprises a processor 16, at least one first pressure sensor 18 arranged on a first zone ZI located on one side of the first vertical central plane (XI, ZI), and a second pressure sensor 20 arranged on a second zone Z2 located on the other side of the first vertical central plane (XI, ZI). The first vertical central plane (XI, ZI) being defined as the first vertical central plane (XI, ZI) illustrated in [Fig. I]. Steps 100 to 124 of the detection process according to the invention can be implemented by the detection system according to the second embodiment. In particular, the detection system according to the second embodiment includes a step for determining the presence or absence of a support on an area. This step includes the following steps: i) determine 114 a subsequent characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a subsequent period, ii) compare 116 the following characteristic value to said permissible variation range defined for the sensor considered; iii) determine 118 an absence of support on the area considered if the following characteristic value is not within the permissible variation range defined for said sensor considered or determine a presence of support when the following characteristic value is within the permissible variation range defined for said sensor considered.

[0057] The method for detecting an inappropriate posture implemented by the second detection system further includes a step 122 of repeating steps i) to iii) for a second defined duration D2. The step of generating a warning signal is implemented only if an absence or presence of support is determined continuously for a duration greater than the second defined duration.

[0058] In this embodiment, when an absence of support has been determined in the first zone Z1 and a presence of support has been determined in the second zone Z2, then the generated warning signal is representative of a trunk position rotated to the side. Preferably, the detection device 15 according to the second embodiment further comprises a first front pressure sensor 30 and a first rear pressure sensor 32, as illustrated in [Fig. 6]. The first front pressure sensor 30 is located on a front area ZA of the seat situated in front of a vertical transverse plane (Y, Z). The first rear pressure sensor 32 is located on a rear area ZR of the seat situated behind the vertical transverse plane (Y, Z). The plane vertical transverse (Y, Z) is defined and positioned in the same way as the vertical transverse (Y, Z) plane illustrated in [Fig.1].

[0059] When a lack of support has been determined on the rear area ZR, the generated warning signal is representative of a pelvis position in front of the seat occupant.

[0060] Alternatively, the detection device 15 according to the second embodiment further comprises four pressure sensors arranged on the seat as illustrated in [Fig.1].

[0061] In this case, the seat 4 has two lateral edges 33, 36. A second vertical central plane (X2, Z2) is defined midway between the two lateral edges of the seat. The front zone ZA has a first front zone ZA1 of the seat located on one side of the second vertical central plane and a second front zone ZA2 of the seat located on the other side of the second vertical central plane (X2, Z2). The rear zone has a first rear zone ZR1 of the seat located on one side of the second vertical central plane (X2, Z2) and a second rear zone ZR2 of the seat located on the other side of the second vertical central plane (X2, Z2). The detection device 15 includes a second front pressure sensor 34 located on the second front zone ZA2) the first front pressure sensor 30 being located on the first front zone ZA1. The detection device 15 further includes a second rear pressure sensor 37 located on the second rear zone ZR2, the first rear pressure sensor 32 being located on the first rear zone ZR1. The detection process implemented by the second detection system comprises the following steps: consider each pressure sensor among the second front pressure sensor 34 and the second rear pressure sensor 37, - for each sensor considered: a) determine 106 a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine 108 an permissible variation range defined for the sensor in question as a function of said characteristic value, (c) determine 114, 116, 118, 120 the presence or absence of support on an area from the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, and - generate a warning signal when a lack of support has been detected in the first zone before ZA1 or in the second zone before ZA2, the generated warning signal being representative of a crossed leg position on the other leg of the seat occupant. Figure 5 represents a detection system according to a third embodiment that can implement the detection method according to the invention. In this third embodiment, a horizontal central plane (X,Y) is defined. This horizontal central plane (X,Y) extends midway between the upper edge 12 and the lower edge 14 of the seat back. The detection system 15 according to this third embodiment comprises a processor 16, a first pressure sensor 18 arranged in a first zone Z1 located above the first vertical central plane (X,Z), and a second pressure sensor 20 arranged in a second zone Z2 located below the first vertical central plane (X,Z). Steps 100 to 124 of the detection process according to the invention can be implemented by the detection system according to the second embodiment. In particular, the detection system according to the second embodiment includes a step for determining the presence or absence of a support on an area. This step includes the following steps: i) determine 114 a subsequent characteristic value representative of the capacitive values ​​measured by the pressure sensor in question during a subsequent period, ii) compare 116 the following characteristic value to said permissible variation range defined for the sensor considered; iii) determine 118 an absence of support on the area considered if the following characteristic value is not within the permissible variation range defined for said sensor considered or determine a presence of support when the following characteristic value is within the permissible variation range defined for said sensor considered.

[0062] The method for detecting an inappropriate posture implemented by the second detection system further includes a step 122 of repeating steps i) to iii) for a second defined duration D2. The step of generating a warning signal is implemented only if an absence or presence of support is determined continuously for a duration greater than the second defined duration.

[0063] When an absence of support has been determined in the first zone ZI and in the second zone Z2, then the generated warning signal is representative of a forward-leaning position of the seat occupant.

[0064] Preferably, the seat 4 of the detection system according to a third embodiment comprises two lateral edges 33, 36. A second central vertical plane (X2, Z2) is defined midway between the two lateral edges of the seat. The front zone ZA comprises a first front zone ZA1 of the seating arranged with a side of the second central vertical plane and a second front zone ZA2 of the seat arranged on the other side of the second central vertical plane (X2, Z2), the rear area includes a first rear area ZR1 of the seat located on one side of the second central vertical plane (X2, Z2), a second rear area ZR2 of the seat located on the other side of the second central vertical plane (X2, Z2). The detection device 15 includes a second front pressure sensor 37 located on the second front zone ZA2, the first front pressure sensor 30 is located on the first front zone ZA1. The detection device 15 further includes a second rear pressure sensor 37 located on the second rear zone ZR2, the first rear pressure sensor 34 being located on the first rear zone (RL The detection process implemented by the detection system according to the third embodiment comprises the following steps: - consider each pressure sensor, starting with the second pressure sensor before 37 and the second rear pressure sensor 37, - for each sensor considered: a) determine 106 a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine 108 an permissible variation range defined for the sensor considered as a function of said characteristic value, c) determine 114, 116, 118, 120 the presence or absence of support on an area from the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate 124 a warning signal when an absence of support has been determined on the first zone before ZA1 or on the second zone before ZA2, the generated warning signal being representative of a position of one leg crossed over the other leg of the seat occupant.

[0065] Alternatively, the detection system according to the fourth embodiment may include two pressure sensors as illustrated in [Fig.6].

[0066] Alternatively, the detection system according to another embodiment may include four pressure sensors as illustrated in [Fig.1].

Claims

Demands

1. Method for detecting an inappropriate posture of an occupant seated on a seat (2) of a vehicle, in particular a motor vehicle; the seat (2) having a seat (4) and a backrest (6) hinged to the seat, the backrest (6) comprising two lateral edges (8, 10), an upper edge (12) and a lower edge (14) adjacent to the seat; a first vertical central plane ((X1,Z1)) extending between and midway between the two lateral edges (8, 10), a first horizontal central plane ((X,Y)) extending between and midway between the upper edge (12) and the lower edge (14);the process being implemented by a detection system (15) comprising a processor (16), at least a first pressure sensor (18) arranged on a first zone (Z1) located on one side of the first vertical central plane ((X1,Z1)) and above the first horizontal central plane ((X,Y)), a second pressure sensor (20) arranged on a second zone (Z2) located on the other side of the first vertical central plane ((X1,Z1)) and above the first horizontal central plane ((X,Y)), a third pressure sensor (22) arranged on a third zone (Z3) located on said side of the first vertical central plane ((X1,Z1)) and below the first horizontal central plane ((X,Y)), a fourth pressure sensor (24) arranged on a fourth zone (Z4) located on said other side of the first vertical central plane ((X1,Z1)) and below the first horizontal central plane ((X,Y));the method comprising a triggering step (100) of a measurement phase comprising time periods during which capacitive values ​​are measured by the first, second, third and fourth pressure sensors; the method further comprising the following steps implemented by the processor during the measurement phase:; - upon detection (102) of the presence of an occupant on the seat, activate (104) a clock to signal the end of a first defined duration (Dl); - after the first defined duration (Dl), consider each pressure sensor among the first, second, third, fourth pressure sensors, - for each pressure sensor considered: a) determine (106) a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine (108) an permissible variation range defined for the sensor considered as a function of said characteristic value, c) determine (114, 116, 118, 120, 122) the presence or absence of a support on an area from the permissible variation range defined for the sensor considered and the capacitive values ​​measured during a subsequent period by the pressure sensor considered arranged in said area, - generate (124) a warning signal when an absence of a support has been determined on at least one area among the areas considered.

2. A method for detecting an inappropriate posture according to claim 1, wherein the step of determining the presence or absence of pressure on an area comprises the following steps: i) determining (114) a subsequent characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a subsequent period, ii) comparing (116) the subsequent characteristic value to said permissible range of variation defined for the sensor considered; iii) determining (118) an absence of pressure on the area considered if the subsequent characteristic value is not within the permissible range of variation defined for said sensor considered or determining the presence of pressure when the subsequent characteristic value is within the permissible range of variation defined for said sensor considered.

3. Method for detecting an inappropriate posture according to claim 2, further comprising a step of repeating (122) steps i) to iii) for a second defined duration (D2) and wherein the step of generating a warning signal is implemented only if an absence of support is determined continuously for a duration at least equal to the second defined duration (D2).

4. A detection method according to any one of claims 1 to 3, wherein if the presence of a support has been determined on the first zone (Z1) and on the second zone (Z2) and the absence of a support has been determined on the third zone (Z3) and on the fourth zone (Z4), then the generated warning signal is representative of a pelvis position in front of the seat occupant.

5. A detection method according to any one of claims 1 to 3, wherein if an absence of support has been determined on the first zone (Z1) and the third zone (Z3), and that a support presence has been determined on the second zone (Z2) and the fourth zone (Z4), then the generated warning signal is representative of a trunk position rotated to the side.

6. A detection method according to any one of claims 1 to 3, wherein if an absence of support has been determined on the first zone (Z1) and on the second zone (Z2) and a presence of support has been determined on the third zone (Z3) and on the fourth zone (Z4) then the generated warning signal is representative of a forward-leaning position of the seat occupant.

7. A method for detecting an inappropriate posture according to any one of claims 1 to 6, wherein the seat (4) has a front edge (26) and a rear edge (28), a vertical transverse plane (Y,Z) being defined midway between the front edge (26) of the seat and the rear edge (28) of the seat, the detection device (15) comprises at least one first front pressure sensor (30) disposed on a front area of ​​the seat (ZA) located in front of the vertical transverse plane (Y,Z), and one first rear pressure sensor (32) disposed on a rear area of ​​the seat (ZR) located behind the vertical transverse plane (Y,Z); the method comprising the following steps: - considering each pressure sensor among the first front pressure sensor (30) and the rear pressure sensor (32),For each sensor considered: a) determine (106) a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine (108) an permissible variation range defined for the sensor considered as a function of said characteristic value, c) determine (114, 116, 118, 120, 122) the presence or absence of support on an area from the permissible variation range defined for the sensor considered and the capacitive values ​​measured during a subsequent period by the pressure sensor considered arranged in said area, - generate (124) a warning signal when an absence of support has been determined on the rear area (RA), the generated warning signal being representative of a pelvis position in front of the seat occupant.

8.

9. A method for detecting inappropriate posture according to claim 7, wherein the seat has two lateral edges (33, 36), a second vertical central plane (X2, Z2) being defined midway between the two lateral edges of the seat, the front zone (ZA) comprising a first front zone (ZA1) of the seat disposed on one side of the second vertical central plane (Y,Z), and a second front zone (ZA2) of the seat disposed on the other side of the second vertical central plane (Y,Z), the rear zone (ZR) comprising a first rear zone (ZR1) of the seat located on one side of the second vertical central plane (Y,Z), and a second rear zone (ZR2) of the seat located on the other side of the second vertical central plane (Y,Z), the detection device (15) comprising a second front pressure sensor (34) disposed on the second front zone (ZA2), the first front pressure sensor (30) being located on the first front zone (ZA1),The detection device (15) further comprises a second rear pressure sensor (37) disposed on the second rear zone (ZR2), the first rear pressure sensor (32) being located on the first rear zone (ZR1), the method comprising the following steps:, - consider each pressure sensor from the second front pressure sensor (34) and the second rear pressure sensor (37) for each sensor considered: a) determine (106) a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine (108) an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine (114, 116, 118, 120) the presence or absence of support on an area from the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate a warning signal when a lack of support has been determined on the first front zone or on the second front zone, the generated warning signal being representative of a position of one leg crossed over the other leg of the seat occupant. Method for detecting an inappropriate posture of an occupant seated on a seat (2) of a vehicle, in particular of a motor vehicle; the seat (2) having a seat (4) and a backrest (6) hinged to the seat, the backrest (6) comprising two lateral edges (8, 10), a first central vertical plane ((XI, Z1)) extending between and midway between the two lateral edges; the method being implemented by a detection system (15) comprising a processor (16), at least one first pressure sensor (18) arranged on a first zone (Z1) located on one side of the first central vertical plane ((XI, Z1)), and a second pressure sensor (20) arranged on a second zone (Z2) located on the other side of the first central vertical plane ((XI, Z1)); the method comprising a triggering step (100) of a measurement phase comprising time periods during which capacitive values ​​are measured by the first and second pressure sensors;the process further comprising the following steps implemented by the processor during the measurement phase:; - upon detection (102) of the presence of an occupant on the seat, activate (104) a clock to signal the end of a first defined duration (Dl); - after the first defined duration (Dl), consider each pressure sensor between the first pressure sensor (18) and the second pressure sensor (20), for each sensor considered: a) determine (106) a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine (108) an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine (114, 116, 118, 120) the presence or absence of support on an area from the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate (124) a warning signal when a lack of support has been determined in at least one zone between the first zone (Z1) and the second zone (Z2).

10. A method for detecting an inappropriate posture of an occupant seated on a seat (2) of a vehicle, in particular a motor vehicle; the seat (2) having a seat (4) and a backrest (6) hinged to the seat, the a backrest (6) comprising an upper edge (12) and a lower edge (14) adjacent to the seat; a horizontal central plane ((X,Y)) extending midway between the upper edge (12) and the lower edge (14); the method being implemented by a detection system (15) comprising a processor (16), at least one first pressure sensor (18) arranged in a first zone (Z1) located above the horizontal central plane ((X,Y)), and a second pressure sensor (20) arranged in a second zone (Z2) located below the horizontal central plane ((X,Y)); the method comprising a triggering step (100) of a measurement phase comprising time periods during which capacitive values ​​are measured by the first (18) and the second (20) pressure sensors; the method further comprising the following steps implemented by the processor during the measurement phase: - upon detection (102) of the presence of an occupant on the seat, activate (104) a clock to signal the end of a first defined duration (Dl); - after the first defined duration (Dl), consider each pressure sensor between the first pressure sensor (18) and the second pressure sensor (20), for each sensor considered: a) determine (106) a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine (108) an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine (114, 116, 118, 120) the presence or absence of support on an area from the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate (124) a warning signal when a lack of support has been determined in at least one zone between the first zone and the second zone.

11. A method for detecting an inappropriate posture according to any one of claims 9 and 10, wherein the seat (4) comprises a front edge (26) and a rear edge (28), a vertical transverse plane (Y, Z) being defined between and midway to the front edge (26) of the seat and rear edge (28) of the seat, the detection device (15) comprises at least a first front pressure sensor (30) disposed on a front area (ZA) of the seat located in front of the vertical transverse plane (Y, Z), and a first rear pressure sensor (32) disposed on a rear area (ZR) of the seat located behind the vertical transverse plane (Y, Z), the method comprising the following steps: - consider each pressure sensor from the first front pressure sensor (30) and the first rear pressure sensor (32), - for each sensor considered: a) determine (106) a characteristic value representative of the capacitive values ​​measured by the pressure sensor considered during a first period, b) determine (108) an permissible variation range defined for the sensor in question as a function of said characteristic value, c) determine (114, 116, 118, 120) the presence or absence of support on an area from the permissible variation range defined for the sensor in question and the capacitive values ​​measured during a subsequent period by the pressure sensor in question arranged in said area, - generate (124) a warning signal when a lack of support has been determined on the rear area, the generated warning signal being representative of a pelvis position in front of the seat occupant.

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