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

Abstract

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

Description

Title of the invention: Method for detecting an inappropriate posture of an occupant sitting on 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 unsuitable posture detection system making it possible to inform the occupant of the seat that he is occupying either an unsafe position in relation to his driving or an uncomfortable position which risks in the long term generating fatigue or muscular or joint pain in the back or neck pain.

[0004] The aim of the present invention is to propose a reliable and robust method for detecting unsuitable 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 midway between the two lateral edges, a first horizontal central plane extending between and midway 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 area 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 area 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 area 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 area 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 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 of the presence of an occupant on the seat, start a clock capable of signaling the end of a first defined duration; - after the first defined duration, consider each pressure sensor among the first, second, third, fourth pressure sensors,

[0006] - for each pressure 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 admissible variation range defined for the sensor considered as a function of said characteristic value, (c) determining the presence or absence of pressure on an area from the permissible variation range defined for the sensor in question and the capacitive values measured during a following period by the pressure sensor in question arranged in said area, - generate a warning signal when an absence of support has been determined on at least one zone among the zones considered.

[0007] The features set forth in the following paragraphs may optionally be implemented. They may be implemented independently of one another or in combination with one another: -the step of determining the presence or absence of support on an area includes the following steps: (i) determine a following characteristic value representative of the capacitive values measured by the pressure sensor considered during a following period, (ii) compare the following characteristic value with the said permissible variation range defined for the sensor considered; iii) determine the absence of a support on the area considered if the following characteristic value is not included in the admissible variation range defined for said sensor considered or determine the presence of a support when the following characteristic value is included in the admissible variation range defined for said sensor considered.

[0008] -The method further comprises 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 press is determined continuously for a duration at least equal to the second defined duration. - If the presence of support has been determined in the first zone and in the second zone and the absence of support has been determined in the third zone and in the fourth zone, then the warning signal generated is representative of a pelvic 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 position of the trunk 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 warning signal generated is representative of a forward leaning position of the seat occupant.

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

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

[0011] The invention also relates to A): 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, a first vertical central 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 zone located on one side of the first vertical central plane, and a second pressure sensor arranged on a second zone located on the other side of the first vertical central plane; the method comprising a step of triggering a measurement phase comprising time periods during which capacitive values are measured by the first and second pressure sensors;the method further comprising the following steps implemented by the processor during the measurement phase: ; - upon detection of the presence of an occupant on the seat, start a clock capable of signaling the end of a first defined duration; - after the first defined duration, consider each pressure sensor among the first pressure sensor and the second pressure sensor, for each sensor considered: a) determining a characteristic value representative of the capacitive values measured by the pressure sensor considered during a first period, b) determining an admissible variation range defined for the sensor considered as a function of said characteristic value, c) determining the presence or absence of pressure on an area from the admissible variation range defined for the sensor considered and the capacitive values measured during a following period by the pressure sensor considered arranged in said area, - generate a warning signal when an absence of support has been determined on at least one zone among 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 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 an upper edge and a lower edge adjacent to the seat; a horizontal central plane extending 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 above the horizontal central plane, and a second pressure sensor arranged on a second zone located below the horizontal central plane; the method comprising a step of triggering a measurement phase comprising time periods during which capacitive values are measured by the first and second pressure sensors;the method further comprising the following steps implemented by the processor during the measurement phase: ; - upon detection of the presence of an occupant on the seat, start a clock capable of signaling the end of a first defined duration; - after the first defined duration, consider each pressure sensor among 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 admissible variation range defined for the sensor considered as a function of said characteristic value, (c) determining the presence or absence of pressure on an area from the permissible variation range defined for the sensor in question and the capacitive values measured during a following period by the pressure sensor in question arranged in said area, - generate a warning signal when an absence of support has been determined on at least one zone among 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 pressure on an area comprises the following steps: i) determining a following characteristic value representative of the capacitive values measured by the pressure sensor considered during a following period, ii) comparing the following characteristic value with said admissible variation range defined for the sensor considered; iii) determine the absence of a support on the area considered if the following characteristic value is not included in the admissible variation range defined for said sensor considered or determine the presence of a support when the following characteristic value is included in the admissible 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 press is continuously determined for a duration greater than the second defined duration.

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

[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 midway between the front edge of the seat and the rear edge of the seat, the detection device comprises at least a first front pressure sensor arranged on a front area of the seat located in front of the vertical transverse plane, and a first rear pressure sensor arranged on a rear area of the seat located behind the vertical transverse plane, the method comprising the following steps: - consider each pressure sensor among the first front pressure sensor and the first rear pressure sensor, - for each sensor considered: a) determining a characteristic value representative of the capacitive values measured by the pressure sensor considered during a first period, b) determining an admissible variation range defined for the sensor considered as a function of said characteristic value, (c) determining the presence or absence of pressure on an area from the permissible variation range defined for the sensor in question and the capacitive values measured during a following period by the pressure sensor in question arranged in said area, - generate a warning signal when an absence of support has been determined on the rear area, the generated warning signal being representative of a pelvic 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 halfway between the two lateral edges of the seat, the front zone comprises a first front zone of the seat arranged on one side of the second vertical central plane and a second front zone of the seat arranged on the other side of the second vertical central plane, the rear zone comprises a first rear zone of the seat located on one side of the second vertical central plane, a second rear zone of the seat located on the other side of the second vertical central plane, the detection device comprises a second front pressure sensor arranged on the second front zone, the first front pressure sensor being located on the first front zone, the detection device (further comprises a second rear pressure sensor arranged on the second rear zone, the first rear pressure sensor being located on the first rear zone, the process comprising the following steps: - consider each pressure sensor among 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 considered during a first period, (b) determine an admissible variation range defined for the sensor considered as a function of said characteristic value, (c) determining the presence or absence of pressure on an area from the permissible variation range defined for the sensor in question and the capacitive values measured during a following period by the pressure sensor in question arranged in said area, - generate a warning signal when an absence 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 occupant of the seat. Brief description of the figures

[0018] [Fig.l] 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 a portion of a detection system that can be added to the detection system illustrated in [Fig.l];

[0020] [Fig.3] is a diagram representing the steps of the detection method 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 of 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 the present application, the terms "upper", "lower", "in front", "behind", "front", "rear" are to be interpreted with regard to the usual position of a seat of a motor vehicle. The front of the seat of a vehicle corresponds to the front of the vehicle considering the normal direction of travel of the vehicle.

[0026] In the present application, longitudinal direction X means a horizontal direction extending between the front and the rear of the vehicle seat. Transverse direction Y means a horizontal direction, extending from one side of the seat to the other side of the seat. Vertical direction Z means the direction perpendicular to the longitudinal directions X and transverse directions Y.

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

[0028] With reference to [Fig.l], 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) extending between and midway between the two lateral edges 8, 10, and a first horizontal central plane (X,Y) extending between and midway between the upper edge 12 and the lower edge 14 of the backrest are defined. These plans allow four zones to be defined on the file. In particular, a first zone ZI is located on one side of the first vertical central plane (XI,Zl) 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,Zl) 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.l], the sensors located on the backrest comprise a first pressure sensor 18 arranged on the first zone Zl, 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 comprises a front edge 26, a rear edge 28 and two lateral edges 33, 36.

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

[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). In the same way, 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 include a first front pressure sensor 30 arranged on the first front zone ZA1 of the seat, a second front pressure sensor 34 arranged 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 arranged on the second rear zone ZR2.

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

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

[0039] Then, the method comprises a step 102 of detecting the presence of an occupant on the seat. This step can be carried out from the capacitance values measured according to a known method or from 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 a step 106, a characteristic value representative of 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 a step 108, an admissible variation range defined for the sensor in question is determined. This admissible variation range is determined as a function of said characteristic value. For example, the lower value of the admissible variation range is equal to the characteristic value minus 15% of the characteristic value and the upper value of the admissible variation range is equal to the characteristic value plus 15% of the characteristic value.

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

[0044] During a step 112, the method 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 a support is determined on each zone considered from the capacitive values measured by the pressure sensors arranged in said zones considered. 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 next characteristic value is determined from the capacitive values generated during a following period by the pressure sensor in question. This next characteristic value is representative of the capacitive values measured during a following period. In the present patent application, the term "next 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 throughout the duration of the measurement phase. This next characteristic value is, for example, an average value of the capacitive values measured during a following period. Alternatively, the next characteristic value is a median value of the capacitive values measured during a following period.

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

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

[0048] During a step 124, a warning signal is generated when an absence of a press has been determined on at least one zone among the zones considered.

[0049] In particular, if a presence of a support has been determined in the first zone Z1 and in the second zone Z2 and an 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 pelvic position in front of the occupant of the seat.

[0050] When the seat comprises four sensors on the seat in addition to the four sensors on the backrest, the warning signal representative of a pelvic position in front of the occupant of the seat is confirmed by a determination of an absence of pressure 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 Z1 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 position of the trunk pivoted 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 Z1 and on the third zone Z3, then the generated warning signal is also representative of a position of the trunk pivoted to the side.

[0053] When an absence of support has been determined in the first zone Z1 and in the second zone Z2 and a presence of support has been determined in the third zone Z3 and in the fourth zone Z4 then the generated warning signal is representative of a forward leaning position of the occupant of the seat.

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

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

[0056] [Fig.4] represents a detection system according to a second embodiment able to implement 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, Zl). The first vertical central plane (XI, Zl) being defined as the first vertical central plane (XI, Zl) illustrated in [Fig.l]. Steps 100 to 124 of the detection method 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 comprises a step of determining the presence or absence of pressure on an area. This step comprises the following steps: i) determine 114 a following characteristic value representative of the capacitive values measured by the pressure sensor considered during a following period, ii) compare 116 the following characteristic value to said admissible 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 included in the admissible variation range defined for said sensor considered or determine a presence of support when the following characteristic value is included in the admissible variation range defined for said sensor considered.

[0057] The method for detecting an inappropriate posture implemented by the second detection system further comprises 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 a support is determined continuously for a duration greater than the second defined duration.

[0058] In this embodiment, when an absence of a support has been determined in the first zone Z1 and a presence of a support has been determined in the second zone Z2 then the generated warning signal is representative of a position of the trunk pivoted 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 arranged on a front area ZA of the seat located in front of a vertical transverse plane (Y, Z). The first rear pressure sensor 32 is arranged on a rear area ZR of the seat located 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 plane (Y, Z) shown in [Fig.l].

[0059] When an absence of support has been determined on the rear zone ZR, the warning signal generated is representative of a pelvic position in front of the occupant of the seat.

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

[0061] In this case, the seat 4 comprises two lateral edges 33, 36. A second vertical central plane (X2, Z2) is defined halfway between the two lateral edges of the seat. The front zone ZA comprises a first front zone ZA1 of the seat arranged on one side of the second vertical central plane and a second front zone ZA2 of the seat arranged on the other side of the second vertical central plane (X2, Z2), the rear zone comprises a first rear zone ZR1 of the seat located on one side of the second vertical central plane (X2, Z2), 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 comprises a second front pressure sensor 34 arranged 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 arranged on the second rear zone ZR2, the first rear pressure sensor 32 being located on the first rear zone ZR1. The detection method implemented by the second detection system comprises the following steps: considering 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 admissible variation range defined for the sensor considered as a function of said characteristic value, c) determining 114, 116, 118, 120 the presence or absence of pressure on an area from the admissible variation range defined for the sensor considered and the capacitive values measured during a following period by the pressure sensor considered arranged in said area, and - generate 124 a warning signal when an absence of support has been determined on the first front zone ZA1 or on the second front zone ZA2, the generated warning signal being representative of a position of a crossed leg on the other leg of the seat occupant. [Fig. 5] represents a detection system according to a third embodiment capable of implementing 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 halfway 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 on a first zone Z1 located above the first vertical central plane (X, Z), and a second pressure sensor 20 arranged on a second zone Z2 located below the first vertical central plane (X, Z). Steps 100 to 124 of the detection method 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 comprises a step of determining the presence or absence of pressure on an area. This step comprises the following steps: i) determine 114 a following characteristic value representative of the capacitive values measured by the pressure sensor considered during a following period, ii) compare 116 the following characteristic value to said admissible 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 included in the admissible variation range defined for said sensor considered or determine a presence of support when the following characteristic value is included in the admissible variation range defined for said sensor considered.

[0062] The method for detecting an inappropriate posture implemented by the second detection system further comprises 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 a support is continuously determined for a duration greater than the second defined duration.

[0063] When an absence of support has been determined in the first zone Z1 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 base 4 of the detection system according to a third embodiment comprises two lateral edges 33, 36. A second vertical central plane (X2, Z2) is defined halfway between the two lateral edges of the base. The front zone ZA comprises a first front zone ZA1 of the seat arranged in a side of the second vertical central plane and a second front zone ZA2 of the seat arranged on the other side of the second vertical central plane (X2, Z2), the rear zone comprises a first rear zone ZR1 of the seat located on one side of the second vertical central plane (X2, Z2), 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 comprises a second front pressure sensor 37 arranged 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 comprises a second rear pressure sensor 37 arranged on the second rear zone ZR2, the first rear pressure sensor 34 being located on the first rear zone (RL The detection method implemented by the detection system according to the third embodiment comprises the following steps: - consider each pressure sensor among the second pressure sensor before 37 and the second rear pressure sensor 37, - for each sensor considered: a) determining 106 a characteristic value representative of the capacitive values measured by the pressure sensor considered during a first period, b) determining 108 an admissible variation range defined for the sensor considered as a function of said characteristic value, c) determining 114, 116, 118, 120 the presence or absence of pressure on an area from the permissible variation range defined for the sensor in question and the capacitive values measured during a following 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 front zone ZA1 or on the second front zone ZA2, the generated warning signal being representative of a position of one leg crossed over the other leg of the occupant of the seat.

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

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

Claims

Claims

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) articulated 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 method being implemented by a detection system (15) comprising a processor (16), at least a first pressure sensor (18) arranged on a first zone (Zl) 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,Zl)) 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,Zl)) and below the first horizontal central plane ((X,Y));the method comprising a step of triggering (100) 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, trigger (104) a clock capable of signaling 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) determining (108) an admissible variation range defined for the sensor considered as a function of said characteristic value, c) determining (114, 116, 118, 120, 122) the presence or absence of a pressure on a zone from the admissible variation range defined for the sensor considered and the capacitive values measured during a following period by the pressure sensor considered arranged in said zone, - generating (124) a warning signal when an absence of a pressure has been determined on at least one zone among the zones considered.

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

3. Method for detecting an inappropriate posture according to claim 2, which further comprises a step of repeating (122) steps i) to iii) for a second defined duration (D2) 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 (D2).

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

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

6. Detection method according to any one of claims 1 to 3, in which if an absence of a support has been determined on the first zone (Z1) and on the second zone (Z2) and a presence 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 forward leaning position of the occupant of the seat.

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 a first front pressure sensor (30) arranged on a front area of the seat (ZA) located in front of the vertical transverse plane (Y,Z), and a first rear pressure sensor (32) arranged 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) determining (106) a characteristic value representative of the capacitive values measured by the pressure sensor considered during a first period, b) determining (108) an admissible variation range defined for the sensor considered as a function of said characteristic value, c) determining (114, 116, 118, 120, 122) the presence or absence of a support on a zone from the admissible variation range defined for the sensor considered and the capacitive values measured during a following period by the pressure sensor considered arranged in said zone, - generating (124) a warning signal when an absence of a support has been determined on the rear zone (ZR), the generated warning signal being representative of a pelvic position in front of the occupant of the seat.,

8.

9. A method for detecting an inappropriate posture according to claim 7, wherein the seat comprises 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) 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), the rear zone (ZR) comprises 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) comprises a second front pressure sensor (34) arranged 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) arranged 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 among the second front pressure sensor (34) and the second rear pressure sensor (37) for each sensor considered: a) determining (106) a characteristic value representative of the capacitive values measured by the pressure sensor considered during a first period, b) determining (108) an admissible variation range defined for the sensor considered as a function of said characteristic value, c) determining (114, 116, 118, 120) the presence or absence of a pressure on an area from the admissible variation range defined for the sensor considered and the capacitive values measured during a following period by the pressure sensor considered arranged in said area, - generate a warning signal when an absence 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 occupant of the seat. 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) articulated to the seat, the backrest (6) comprising two lateral edges (8, 10), a first vertical central plane ((XI, Zl)) 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 (Zl) located on one side of the first vertical central plane ((XI, Z1)), and a second pressure sensor (20) arranged on a second zone (Z2) located on the other side of the first vertical central plane ((XI, Zl)); the method comprising a step of triggering (100) a measurement phase comprising time periods during which capacitive values are measured by the first and second 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, trigger (104) a clock capable of signaling the end of a first defined duration (Dl); - after the first defined duration (Dl), consider each pressure sensor among the first pressure sensor (18) and the second pressure sensor (20), for each sensor considered: a) determining (106) a characteristic value representative of the capacitive values measured by the pressure sensor considered during a first period, b) determining (108) an admissible variation range defined for the sensor considered as a function of said characteristic value, c) determining (114, 116, 118, 120) the presence or absence of a pressure on an area from the admissible variation range defined for the sensor considered and the capacitive values measured during a following period by the pressure sensor considered arranged in said area, - generating (124) a warning signal when an absence of support has been determined on at least one zone among the first zone (Z1) and the second zone (Z2).

10. 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) articulated to the seat, the backrest (6) comprising an upper edge (12) and a lower edge (14) adjacent to the seat; a horizontal central plane ((X,Y)) extending halfway 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 a first pressure sensor (18) arranged on a first zone (Zl) located above the horizontal central plane ((X,Y)), and a second pressure sensor (20) arranged on a second zone (Z2) located below the horizontal central plane ((X,Y)); the method comprising a step of triggering (100) 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, trigger (104) a clock capable of signaling the end of a first defined duration (Dl); - after the first defined duration (Dl), consider each pressure sensor among the first pressure sensor (18) and the second pressure sensor (20), for each sensor considered: a) determining (106) a characteristic value representative of the capacitive values measured by the pressure sensor considered during a first period, b) determining (108) an admissible variation range defined for the sensor considered as a function of said characteristic value, c) determining (114, 116, 118, 120) the presence or absence of pressure on an area from the admissible variation range defined for the sensor in question and the capacitive values measured during a following period by the pressure sensor in question arranged in said area, - generate (124) a warning signal when an absence of a support has been determined on at least one zone among the first zone and the second zone.

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

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