Method for detecting an unfavorable body position of an occupant sitting on a vehicle seat

Abstract

The invention relates to a method for detecting an unfavorable posture of an occupant sitting on a vehicle seat, the method comprising the following steps: - after an initial defined period after the presence of an occupant on the seat has been detected, - for each pressure sensor of the detection system: a) determining (106) a characteristic value representative of the capacitive values measured by the pressure sensor taken into account over a first period of time, b) determining (108) an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining (114, 116, 118, 120, 122) the presence of pressure on a zone on the basis of the permissible variation range defined for the sensor taken into account and the capacitive values measured in a subsequent period, - generating (124) a warning signal when the absence of pressure on at least one zone has been determined.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a method for detecting an unfavorable posture of an occupant sitting on a seat of a vehicle, in particular a motor vehicle. OVERVIEW OF THE INVENTION

[0002] It would be desirable to propose a system for detecting awkward postures, making it possible to warn the seat occupant that he or she is adopting either an unsafe position with regard to driving the vehicle or an uncomfortable position that could lead to fatigue, muscle or back pain or neck pain.

[0003] The aim of the present invention is to propose a reliable and robust method for detecting an unfavorable body posture. SUMMARY OF THE INVENTION

[0004] The subject matter of the present invention is a method for detecting an unfavorable posture of an occupant sitting on a seat of a vehicle, in particular a motor vehicle; wherein the seat has a seat surface and a backrest hinged to the seat surface, wherein the backrest comprises two side edges, an upper edge and a lower edge adjacent to the seat surface; wherein a first vertical center plane extends between the two side edges and in the middle between them, wherein a first horizontal center plane extends between the upper edge and the lower edge of the backrest and in the middle between them.;wherein the method is implemented by a detection system comprising a processor, at least a first pressure sensor arranged in a first zone located on one side of the first vertical center plane and above the first horizontal center plane, a second pressure sensor arranged in a second zone located on the other side of the first vertical center plane and above the first horizontal center plane, a third pressure sensor arranged in a third zone located on the side of the first vertical center plane and below the first horizontal center plane, a fourth pressure sensor arranged in a fourth zone located on the other side of the first vertical center plane and below the first horizontal center plane;wherein the method comprises a step of activating a measurement phase comprising periods during which capacitive values are measured by the first, second, third, and fourth pressure sensors; wherein the method further comprises the following steps, implemented by the processor during the measurement phase: - upon detection of the presence of an occupant on the seat, activation of a clock capable of signalling the end of a first defined period; - after the first defined duration, taking into account each pressure sensor of the first, second, third and fourth pressure sensors, - for each pressure sensor considered: a) determining a characteristic value representative of the capacitive values measured by the pressure sensor taken into account over a first period of time, b) Determining an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured over a subsequent period by the pressure sensor in question located in that zone, - Generating a warning signal when a lack of pressure has been determined on at least one of the zones considered.

[0005] The features disclosed in the following paragraphs may be implemented optionally. They may be implemented independently or in combination with each other: - the step of determining the presence or absence of pressure on a zone comprises the following steps: i) determining a subsequent characteristic value representative of the capacitive values measured by the pressure sensor considered over a subsequent period of time, ii) comparing the subsequent characteristic value with the permissible range of variation defined for the sensor considered; iii) determining the absence of pressure on the zone under consideration if the subsequent characteristic value is not within the permissible range of variation defined for the sensor under consideration, or determining the presence of pressure if the subsequent characteristic value is within the permissible range of variation defined for the sensor under consideration. - The method further comprises a step of repeating steps i) to iii) for a second defined duration, wherein the step of generating a warning signal is implemented only when an absence of pressure is continuously determined for a duration at least equal to the second defined duration. - If the presence of pressure on the first zone and on the second zone is determined and the absence of pressure on the third zone and on the fourth zone is determined, then the warning signal generated is representative of a forward-displaced pelvic position of the seat occupant. - If an absence of pressure on the first and third zones has been determined and a presence of pressure on the second and fourth zones has been determined, then the warning signal generated is representative of a laterally rotated position of the upper body. - If an absence of pressure on the first zone and on the second zone has been determined and a presence of pressure on the third zone and on the fourth zone has been determined, then the warning signal generated is representative of a forward-leaning position of the seat occupant. - the seat surface 4 comprises a front edge and a rear edge, wherein a vertical transverse plane is defined midway between the front edge of the seat surface and the rear edge of the seat surface, the detection device comprises at least a first front pressure sensor arranged in a front zone of the seat surface located in front of the vertical transverse plane, and a first rear pressure sensor arranged in a rear zone of the seat surface located behind the vertical transverse plane; the method comprising the following steps: - Consider each pressure sensor of the first front pressure sensor and the rear pressure sensor, for each sensor considered: a) determining a characteristic value representative of the capacitive values measured by the pressure sensor taken into account over a first period of time, b) Determining an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured over a subsequent period by the pressure sensor in question located in that zone, - generating a warning signal when an absence of pressure on the rear zone has been determined, the generated warning signal being representative of a forward-displaced pelvic position of the seat occupant.

[0006] The seat comprises two side edges, with a second vertical median plane defined midway between the two side edges of the seat surface, the front zone comprises a first front zone of the seat surface arranged on one side of the second vertical median plane and a second front zone of the seat surface arranged on the other side of the second vertical median plane, the rear zone comprises a first rear zone of the seat surface located on one side of the second vertical median plane and a second rear zone of the seat surface located on the other side of the second vertical median plane, the detection device comprises 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 arranged in the second rear zone, wherein the first rear pressure sensor is located in the first rear zone, the method comprising the following steps: - Consider each pressure sensor of 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 taken into account over a first period of time, b) Determining an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured over a subsequent period by the pressure sensor in question located in that zone, - generating a warning signal when an absence of pressure on the first front zone or on the second front zone has been determined, the generated warning signal being representative of a position of a leg of the seat occupant crossed over the other leg.

[0007] The invention further relates to A): a method for detecting an unfavorable posture of an occupant sitting on a seat of a vehicle, in particular a motor vehicle; wherein the seat has a seat surface and a backrest hinged to the seat surface, the backrest comprising two side edges, a first vertical center plane extending between the two side edges and in the middle between them; wherein the method is implemented by a detection system comprising a processor, at least one first pressure sensor arranged in a first zone on one side of the first vertical center plane, and a second pressure sensor arranged in a second zone on the other side of the first vertical center plane; wherein the method comprises a step of activating a measuring phase comprising 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, activation of a clock capable of signalling the end of a first defined period; - after the first defined duration, Considering each pressure sensor of 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 taken into account over a first period of time, b) Determining an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured during a subsequent period by the pressure sensor in question located in that zone, - Generating a warning signal when a lack of pressure on at least one of the first zone and the second zone (Z2) has been determined.

[0008] The invention also relates to B): a method for detecting an unfavorable posture of an occupant sitting on a seat of a vehicle, in particular a motor vehicle; wherein the seat has a seat surface and a backrest hinged to the seat surface, the backrest comprising an upper edge and a lower edge adjacent to the seat surface; wherein a horizontal center plane extends midway between the upper edge and the lower edge; wherein the method is implemented by a detection system comprising a processor, at least one first pressure sensor arranged in a first zone above the horizontal center plane, and a second pressure sensor arranged in a second zone below the horizontal center plane; wherein the method comprises a step of activating a measuring phase comprising 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, activation of a clock capable of signalling the end of a first defined period; - after the first defined duration, taking into account each pressure sensor of 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 taken into account over a first period of time, b) Determining an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured during a subsequent period by the pressure sensor in question located in that zone, - Generating a warning signal when a lack of pressure has been determined on at least one of the first zone and the second zone.

[0009] According to one embodiment, in the method according to (A) and (B), the step of determining the presence or absence of pressure on a zone comprises the following steps: i) determining a subsequent characteristic value representative of the capacitive values measured by the pressure sensor considered over a subsequent period of time, ii) comparing the subsequent characteristic value with the permissible range of variation defined for the sensor considered; iii) determining that no pressure is exerted on the zone under consideration if the subsequent characteristic value is not within the permissible range of variation defined for the sensor under consideration, or determining the presence of pressure if the subsequent characteristic value is within the permissible range of variation defined for that sensor under consideration. - According to one embodiment, the detection method according to A) and B) further comprises a step of repeating steps i) to iii) for a second defined duration, wherein the step of generating a warning signal is implemented only if an absence or presence of pressure is continuously determined for a duration greater than the second defined duration.

[0010] In the detection method according to A), if an absence of pressure on the first zone and a presence of pressure on the second zone has been determined, the generated warning signal is representative of a sideways turned position of the upper body.

[0011] According to one embodiment, in the detection method according to B), if an absence of pressure on the first zone and on the second zone has been determined, the generated warning signal is then representative of a forward-leaning position of the occupant of the seat.

[0012] According to one embodiment, in the detection method according to A) and B), the seat surface comprises a front edge and a rear edge, wherein a vertical transverse plane is defined between and midway between the front edge of the seat surface and the rear edge of the seat surface, the detection device comprises at least a first front pressure sensor arranged in a front zone of the seat surface located in front of the vertical transverse plane and a first rear pressure sensor arranged in a rear zone of the seat surface located behind the vertical transverse plane, the method comprising the following steps: - Consider each pressure sensor of 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 taken into account over a first period of time, b) Determining an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured during a subsequent period by the pressure sensor in question located in that zone, - generating a warning signal when an absence of pressure on the rear zone has been determined, the generated warning signal being representative of a forward-displaced pelvic position of the seat occupant.

[0013] According to one embodiment, in the detection method according to A) and B), the seat surface comprises two side edges, wherein a second vertical median plane is defined in the middle between the two side edges of the seat surface, the front zone comprises a first front zone of the seat surface arranged on one side of the second vertical median plane and a second front zone of the seat surface arranged on the other side of the second vertical median plane, the rear zone comprises a first rear zone of the seat surface located on one side of the second vertical median plane and a second rear zone of the seat surface located on the other side of the second vertical median plane, the detection device comprises 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 arranged in the second rear zone, wherein the first rear pressure sensor is located in the first rear zone, the method comprising the following steps: - Consider each pressure sensor of the second front pressure sensor 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 taken into account over a first period of time, b) Determining an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured over a subsequent period by the pressure sensor in question located in that zone, - generating a warning signal when an absence of pressure on the first front zone or on the second front zone has been determined, the generated warning signal being representative of a position of a leg of the seat occupant crossed over the other leg. SHORT DESCRIPTION OF THE CHARACTERS [ Fig. 1] is a schematic perspective view of a seat and a detection system according to a first embodiment of the invention; [ Fig. 2] is a schematic perspective view of the seat and part of a detection system belonging to the Fig. 1 shown detection system can be added; [ Fig. 3] is a diagram showing the steps of the method according to the invention; [ Fig. 4] is a schematic perspective view of a seat and a detection system according to a second embodiment; [ Fig. 5] is a schematic perspective view of a seat and a detection system according to a third embodiment; [ Fig. 6] is a schematic perspective view of a seat and a detection system according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] In this patent application, identical or similar elements are provided with the same reference numerals and will not be described a second time.

[0015] In this application, the terms "upper," "lower," "front," "rear," "forward," and "rearward" are to be interpreted with reference to the usual position of a seat of a motor vehicle. The front of a vehicle seat corresponds to the front of the vehicle, taking into account the vehicle's normal direction of travel.

[0016] In the present application, the longitudinal direction X is understood to be a horizontal direction extending between the front and rear of the vehicle seat. The transverse direction Y is a horizontal direction extending from one side of the seat to the other side of the seat. The vertical direction Z is the direction perpendicular to the longitudinal direction X and the transverse direction Y.

[0017] A motor vehicle seat 2 comprises a seat surface 4 and a backrest 6 which is hinged to the seat surface 4.

[0018] With reference to Fig. 1, the backrest 6 comprises two side edges 8, 10, an upper edge 12 and a lower edge 14 adjacent to the seat.

[0019] For the purposes of this patent application, a first vertical median plane (X1, Z1) is defined which extends between the two side edges 8, 10 and midway therebetween, and a first horizontal median plane (X, Y) is defined which extends between the upper edge 12 and the lower edge 14 of the backrest and midway therebetween.

[0020] The levels define four zones on the backrest.

[0021] In particular, a first zone Z1 is located on one side of the first vertical center plane (X1, Z1) and above the first horizontal center plane (X, Y). A second zone Z2 is located on the other side of the first vertical center plane (X1, Z1) and above the first horizontal center plane (X, Y).

[0022] A third zone Z3 is located on the side of the first vertical center plane (X1, Z1) and below the first horizontal center plane (X, Y). A fourth zone Z4 is located on the other side of the first vertical center plane (X1, Z1) and below the first horizontal center plane (X, Y).

[0023] The detection method according to a first embodiment is implemented by a detection system 15 according to a first embodiment, which comprises a processor 16 and at least four pressure sensors arranged on the backrest.

[0024] With reference to Fig. 1, the sensors located on the backrest comprise a first pressure sensor 18 arranged in the first zone Z1, a second pressure sensor 20 arranged in the second zone Z2, a third pressure sensor 22 arranged in a third zone Z3, and a fourth pressure sensor 24 arranged in the fourth zone Z4 of the backrest.

[0025] According to an advantageous and non-limiting variant, the detection method according to the first embodiment is implemented by a detection system 15 which further comprises four pressure sensors on the seat surface.

[0026] In particular, with reference to Fig. 2, the seat surface 4 comprises a front edge 26, a rear edge 28 and two side edges 33, 36.

[0027] For the purposes of the present patent application, a vertical transverse plane (Y, Z) is defined which is located midway between the front edge 26 of the seat surface and the rear edge 28 of the seat surface, and a second vertical median plane (X2, Z2) which is located midway between the two side edges 33, 36 of the seat surface.

[0028] The seat surface 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 surface comprises a first front zone ZA1 of the seat surface, arranged on one side of the second vertical median plane (Y, Z), and a second front zone ZA2 of the seat surface, arranged on the other side of the second vertical median plane (Y, Z). Similarly, the rear zone ZR of the seat surface 4 comprises a first rear zone ZR1 located on one side of the second vertical median plane (Y, Z) and a second rear zone ZR2 located on the other side of the second vertical median plane (Y, Z).

[0029] With reference to Fig. 2, the sensors located on the seat surface comprise a first front pressure sensor 30 arranged in the first front zone ZA1 of the seat surface, a second front pressure sensor 34 arranged in the second front zone ZA2, a first rear pressure sensor 32 arranged in the first rear zone ZR1, and a second rear pressure sensor 37 arranged in the second rear zone ZR2.

[0030] The pressure sensors, for example, are capacitive sensors with coplanar interlocking electrodes, as described in the patent application published under the number FR 3 126 776.

[0031] With reference to Fig. 3, the method for detecting an unfavorable body posture begins with a step 100 for activating a measurement phase. During the measurement phase, the capacitive values generated by pressure sensors 18 to 24 are measured at regular intervals. The measurement phase includes periods in which multiple measurements are taken. The measurement phase is implemented continuously throughout all steps of the method. Steps 114 to 124 are repeated with the new capacitive values measured during the measurement phase.

[0032] The method then includes a step 102 of detecting the presence of an occupant on the seat. This step can be performed using capacitive values measured using a known method or using other means, such as a camera and an image recognition system. Once the presence of an occupant on the seat has been detected, a clock is started in step 104. The clock is configured to signal the end of a first defined duration D1.

[0033] Then, after the first defined duration, each pressure sensor of the first, second, third and fourth pressure sensors is taken into account.

[0034] Steps 106 to 122 are performed for each pressure sensor considered.

[0035] In step 106, a characteristic value is determined that is representative of the capacitive values generated by each pressure sensor considered. This characteristic value is representative of the capacitive values measured over a first period of time. The first period of time is the first period after the first defined duration D1. This characteristic value is, for example, an average value of the capacitive values measured during the first period of time. Alternatively, the characteristic value is a median value of the capacitive values measured during the first period of time.

[0036] In step 108, a permissible variation range defined for the sensor under consideration is determined. This permissible variation range is determined based on the characteristic value. For example, the lower value of the permissible variation range corresponds to the characteristic value minus 15% of the characteristic value, and the upper value of the permissible variation range corresponds to the characteristic value plus 15% of the characteristic value.

[0037] According to another example, the lower value of the allowable variation range corresponds to the characteristic value minus 20% of the characteristic value and the upper value of the allowable variation range corresponds to the characteristic value plus 20% of the characteristic value.

[0038] In step 110, the permissible variation range defined in step 108 is stored in the memory of the processor 16.

[0039] In step 112, the method returns to step 106, another pressure sensor is considered, and steps 106 through 110 are implemented for that other sensor. Thus, steps 106 through 110 are implemented for each pressure sensor.

[0040] In steps 114 to 122, each zone is considered, and the presence or absence of pressure on each considered zone is determined based on the capacitive values measured by the pressure sensors located in the considered zones. The considered zones 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.

[0041] In step 114, a next characteristic value is determined from the capacitive values generated by the pressure sensor under consideration in a subsequent time period. This subsequent characteristic value is representative of the capacitive values measured over a subsequent time period. In the present patent application, the term "subsequent time period" refers to the time period immediately following the first time period, as well as all subsequent time periods. Step 114 is repeated for each new time period throughout the measurement phase. This characteristic value is, for example, an average value of the capacitive values measured during the subsequent time period. Alternatively, the characteristic value is a median value of the capacitive values measured during the subsequent time period.

[0042] In step 116, the subsequent characteristic value is compared with the permissible range of variation defined for the sensor considered and stored in the processor memory.

[0043] If the subsequent characteristic value lies within the allowable variation range, the presence of a pressure in the considered zone is determined in step 118. If the subsequent characteristic value lies outside the allowable variation range, the absence of a pressure in the considered zone is determined in step 118.

[0044] Steps 114 to 118 are repeated in step 120 for all pressure sensors.

[0045] Preferably, the method comprises step 122, in which steps 114 to 118 are repeated based on the capacitive values generated by the pressure sensors over the subsequent time periods. These steps 114 to 118 are repeated multiple times over a duration equal to at least the second defined duration D2. And steps 123 and 124 are implemented only if no pressure was detected during the second defined duration.

[0046] In step 123, the set of pressure presence and pressure absence conditions is then analyzed to determine whether the seat occupant is in an unfavorable position on the seat.

[0047] In step 124, a warning signal is generated if an absence of pressure on at least one of the zones considered has been determined.

[0048] In particular, if the presence of pressure on the first zone Z1 and on the second zone Z2 and the absence of pressure on the third zone Z3 and on the fourth zone Z4 have been determined, then the generated warning signal is representative of a forward-displaced pelvic position of the seat occupant.

[0049] If the seat comprises four sensors on the seat cushion in addition to the four sensors on the backrest, the warning signal representative of a forward-displaced pelvic position of the seat occupant is confirmed by determining an absence of pressure on the first rear zone ZR1 based on the capacitive values measured by the first rear pressure sensor 32 and on the second rear zone ZR2 based on the capacitive values measured by the second rear pressure sensor 37.

[0050] If the absence of pressure on the first zone Z1 and on the third zone Z3 was determined and the presence of pressure on the second zone Z2 and on the fourth zone Z4 was determined, then the generated warning signal is representative of a sideways twisted position of the upper body.

[0051] If an absence of pressure on the second zone Z2 and on the fourth zone Z4 has been determined and a presence of pressure on the first zone Z1 and on the third zone Z3 has been determined, then the generated warning signal is also representative of a sideways turned position of the upper body.

[0052] If an absence of pressure on the first zone Z1 and on the second zone Z2 has been determined and a presence of pressure on the third zone Z3 and on the fourth zone Z4 has been determined, then the warning signal generated is representative of a forward-leaning position of the seat occupant.

[0053] If an absence of pressure on the first front zone ZA1 or on the second front zone ZA2 has been determined, the warning signal generated is representative of a position of a leg of the seat occupant crossed over the other leg.

[0054] In step 126, the warning signal may be transmitted to a display device to display an image corresponding to the type of awkward posture detected. Alternatively, the warning signal is transmitted to a sound system that emits an audible warning signal or to a voice system that is capable of selecting a voice message corresponding to the type of awkward posture detected.

[0055] Fig. Figure 4 shows a detection system according to a second embodiment, which can 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 in a first zone Z1 located on one side of the first vertical center plane (X1, Z1), and a second pressure sensor 20 arranged in a second zone Z2 located on the other side of the first vertical center plane (X1, Z1). The first vertical center plane (X1, Z1) is defined as the Fig. 1 shows the first vertical center plane (X1, Z1).

[0056] The steps 100 to 124 of the recognition method according to the invention can be implemented by the recognition system according to the second embodiment.

[0057] In particular, the detection system according to the second embodiment includes a step for determining the presence or absence of pressure on a zone. This step includes the following steps: i) determining 114 a subsequent characteristic value representative of the capacitive values measured by the pressure sensor considered over a subsequent period of time, ii) comparing 116 the subsequent characteristic value with the permissible range of variation defined for the sensor considered; iii) determining 118 the absence of pressure on the zone taken into account if the subsequent characteristic value does not lie within the permissible range of variation defined for the sensor taken into account, or determining the presence of pressure if the subsequent characteristic value lies within the permissible range of variation defined for the sensor taken into account.

[0058] The method for detecting an unfavorable 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 pressure is continuously determined for a duration greater than the second defined duration.

[0059] In this embodiment, when an absence of pressure on the first zone Z1 and a presence of pressure on the second zone Z2 has been determined, the generated warning signal is representative of a sideways rotated position of the upper body.

[0060] 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 shown in Fig. 6. The first front pressure sensor 30 is arranged in a front zone ZA of the seat surface in front of a vertical transverse plane (Y, Z). The first rear pressure sensor 32 is arranged in a rear zone ZR of the seat surface behind the vertical transverse plane (Y, Z). The vertical transverse plane (Y, Z) is defined and positioned in the same way as in Fig. 1 shown vertical transverse plane (Y, Z).

[0061] If an absence of pressure on the rear zone ZR has been determined, the warning signal generated is representative of a forward shifted pelvic position of the seat occupant.

[0062] Alternatively, the detection device 15 according to the second embodiment further comprises four pressure sensors arranged on the seat surface, as shown in Fig. 1 shown.

[0063] In this case, the seat surface 4 comprises two side edges 33, 36. A second vertical center plane (X2, Z2) is defined midway between the two side edges of the seat surface. The front zone ZA comprises a first front zone ZA1 of the seat surface, located on one side of the second vertical center plane, and a second front zone ZA2 of the seat surface, located on the other side of the second vertical center plane (X2, Z2). the rear zone comprises a first rear zone ZR1 of the seat surface located on one side of the second vertical median plane (X2, Z2), a second rear zone ZR2 of the seat surface located on the other side of the second vertical median plane (X2, Z2).

[0064] The detection device 15 comprises a second front pressure sensor 34 arranged in the second front zone ZA2), while the first front pressure sensor 30 is located in the first front zone ZA1.

[0065] The detection device 15 further comprises a second rear pressure sensor 37 arranged in the second rear zone ZR2, while the first rear pressure sensor 32 is located in the first rear zone ZR1.

[0066] The recognition process implemented by the second recognition system includes the following steps: Considering each pressure sensor of 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 taken into account over a first period of time, b) determining 108 an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining 114, 116, 118, 120 the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor taken into account and the capacitive values measured over a subsequent period by the pressure sensor taken into account arranged in that zone, and - generating 124 a warning signal when an absence of pressure on the first front zone ZA1 or on the second front zone ZA2 has been determined, the generated warning signal being representative of a position of a leg of the seat occupant crossed over the other leg.

[0067] Fig. Figure 5 shows a detection system according to a third embodiment, which can implement the detection method according to the invention. In this third embodiment, a horizontal center plane (X, Y) is defined. This horizontal center plane (X, Y) extends midway between the upper edge 12 and the lower edge 14 of the seat backrest. 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 plane (X, Z), and a second pressure sensor 20 arranged in a second zone Z2 located below the first vertical plane (X, Z).

[0068] The steps 100 to 124 of the recognition method according to the invention can be implemented by the recognition system according to the second embodiment.

[0069] In particular, the detection system according to the second embodiment includes a step for determining the presence or absence of pressure on a zone. This step includes the following steps: i) determining 114 a subsequent characteristic value representative of the capacitive values measured by the pressure sensor considered over a subsequent period of time, ii) comparing 116 the subsequent characteristic value with the permissible range of variation defined for the sensor considered; iii) determining 118 the absence of pressure on the zone taken into account if the subsequent characteristic value does not lie within the permissible range of variation defined for the sensor taken into account, or determining the presence of pressure if the subsequent characteristic value lies within the permissible range of variation defined for the sensor taken into account.

[0070] The method for detecting an unfavorable 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 pressure is continuously determined for a duration greater than the second defined duration.

[0071] If an absence of pressure on the first zone Z1 and on the second zone Z2 has been determined, then the warning signal generated is representative of a forward-leaning position of the seat occupant.

[0072] Preferably, according to a third embodiment, the seat surface 4 of the detection system comprises two side edges 33, 36. A second vertical median plane (X2, Z2) is defined midway between the two side edges of the seat surface.

[0073] The front zone ZA comprises a first front zone ZA1 of the seat surface, which is arranged on one side of the second vertical center plane, and a second front zone ZA2 of the seat surface, which is arranged on the other side of the second vertical center plane (X2, Z2), the rear zone comprises a first rear zone ZR1 of the seat surface located on one side of the second vertical median plane (X2, Z2), a second rear zone ZR2 of the seat surface located on the other side of the second vertical median plane (X2, Z2).

[0074] The detection device 15 comprises a second front pressure sensor 37 arranged in the second front zone ZA2, while the first front pressure sensor 30 is located in the first front zone ZA1.

[0075] The detection device 15 further comprises a second rear pressure sensor 37 arranged in the second rear zone ZR2, wherein the first rear pressure sensor 34 is located in the first rear zone ZR1.

[0076] The recognition method implemented by the recognition system according to the third embodiment comprises the following steps: - Considering each pressure sensor of 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 taken into account over a first period of time, b) determining 108 an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining 114, 116, 118, 120 the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor taken into account and the capacitive values measured over a subsequent period by the pressure sensor taken into account, which is arranged in that zone, - generating 124 a warning signal when an absence of pressure on the first front zone AZ1 or on the second front zone ZA2 has been determined, the generated warning signal being representative of a position of a leg of the seat occupant crossed over the other leg.

[0077] Alternatively, the detection system according to the fourth embodiment may comprise two pressure sensors as shown in Fig. 6 shown.

[0078] Alternatively, according to another embodiment, the detection system may comprise four pressure sensors, as shown in Fig. 1 shown. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] FR 3 126 776

[0030]

Claims

[1] Method for detecting an unfavorable posture of an occupant sitting on a seat (2) of a vehicle, in particular a motor vehicle; wherein the seat (2) has a seat surface (4) and a backrest (6) hinged to the seat surface, wherein the backrest (6) comprises two side edges (8, 10), an upper edge (12) and a lower edge (14) adjacent to the seat surface; wherein a first vertical center plane ((X1, Z1)) extends between the two side edges (8, 10) and in the middle between them, wherein a first horizontal center plane ((X, Y)) extends between the upper edge (12) and the lower edge (14) of the backrest and in the middle between them;wherein the method is implemented by a detection system (15) comprising a processor (16), at least one first pressure sensor (18) arranged in a first zone (Z1) located on one side of the first vertical center plane ((X1, Z1)) and above the first horizontal center plane ((X, Y)), a second pressure sensor (20) arranged in a second zone (Z2) located on the other side of the first vertical center plane ((X1, Z1)) and above the first horizontal center plane ((X, Y)), a third pressure sensor (22) arranged in a third zone (Z3) located on the side of the first vertical center plane ((X1, Z1)) and below the first horizontal center plane ((X, Y)), a fourth pressure sensor (24) arranged in a fourth zone (Z4) located on the other side of the first vertical center plane ((X1, Z1)) and below the first horizontal center plane ((X,Y)) is located;wherein the method comprises a step (100) of activating a measurement phase comprising periods during which capacitive values are measured by the first, second, third, and fourth pressure sensors; wherein the method further comprises the following steps, implemented by the processor during the measurement phase: - upon detection (102) of the presence of an occupant on the seat, activating (104) a clock suitable for signalling the end of a first defined period (D1); - after the first defined duration (D1), taking into account each pressure sensor of the first, second, third and fourth pressure sensors, - for each pressure sensor considered: a) determining (106) a characteristic value representative of the capacitive values measured by the pressure sensor taken into account over a first period of time, b) determining (108) an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining (114, 116, 118, 120, 122) the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured over a subsequent period by the pressure sensor in question arranged in that zone, - generating (124) a warning signal when an absence of pressure on at least one of the zones taken into account has been determined. [2] A method for detecting an unfavorable body posture according to claim 1, wherein the step of determining the presence or absence of pressure on a zone comprises the following steps: i) determining (114) a subsequent characteristic value representative of the capacitive values measured by the pressure sensor taken into account over a subsequent period of time, ii) comparing (116) the subsequent characteristic value with the permissible range of variation defined for the sensor considered; iii) determining (118) the absence of pressure on the zone taken into account if the subsequent characteristic value is not within the permissible range of variation defined for the sensor taken into account, or determining the presence of pressure if the subsequent characteristic value is within the permissible range of variation defined for the sensor taken into account. [3] A method for detecting an unfavorable body 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 when an absence of pressure is continuously determined for a duration at least equal to the second defined duration (D2). [4] Detection method according to one of claims 1 to 3, wherein, if a presence of pressure on the first zone (Z1) and on the second zone (Z2) has been determined and an absence of pressure on the third zone (Z3) and on the fourth zone (Z4) has been determined, the generated warning signal is then representative of a forwardly displaced pelvic position of the occupant of the seat. [5] Detection method according to one of claims 1 to 3, wherein, if an absence of pressure on the first zone (Z1) and on the third zone (Z3) has been determined, and a presence of pressure on the second zone (Z2) and on the fourth zone (Z4) has been determined, the generated warning signal is then representative of a sideways turned position of the upper body. [6] Detection method according to one of claims 1 to 3, wherein, if an absence of pressure on the first zone (Z1) and on the second zone (Z2) has been determined, and a presence of pressure on the third zone (Z3) and on the fourth zone (Z4) has been determined, the generated warning signal is then representative of a forward-leaning position of the occupant of the seat. [7] Method for detecting an unfavorable body posture according to one of claims 1 to 6, wherein the seat surface (4) comprises a front edge (26) and a rear edge (28), wherein a vertical transverse plane (Y,Z) is defined midway between the front edge (26) of the seat surface and the rear edge (28) of the seat surface, the detection device (15) comprises at least a first front pressure sensor (30) arranged in a front zone of the seat surface (ZA) located in front of the vertical transverse plane (Y,Z), and a first rear pressure sensor (32) arranged in a rear zone of the seat surface (ZR) located behind the vertical transverse plane (Y,Z); the method comprising the following steps: - Considering each pressure sensor of 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 taken into account over a first period of time, b) determining (108) an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining (114, 116, 118, 120, 122) the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor in question and the capacitive values measured over a subsequent period by the pressure sensor in question arranged in that zone, - generating a warning signal (124) when an absence of pressure on the rear zone (ZR) has been determined, the generated warning signal being representative of a forwardly displaced pelvic position of the seat occupant. [8] Method for detecting an unfavorable body posture according to claim 7, wherein the seat comprises two side edges (33, 36), a second vertical center plane (X2, Z2) being defined midway between the two side edges of the seat surface, the front zone (ZA) comprises a first front zone (ZA1) of the seat surface arranged on one side of the second vertical center plane (Y, Z), and a second front zone (ZA2) of the seat surface arranged on the other side of the second vertical center plane (Y, Z), the rear zone (ZR) comprises a first rear zone (ZR1) of the seat surface located on one side of the second vertical median plane (Y, Z), and a second rear zone (ZR2) of the seat surface located on the other side of the second vertical median plane (Y, Z), the detection device (15) comprises a second front pressure sensor (34) arranged in the second front zone (ZA2), the first front pressure sensor (30) being located in the first front zone (ZA1), the detection device (15) further comprises a second rear pressure sensor (37) arranged in the second rear zone (ZR2), the first rear pressure sensor (32) being located in the first rear zone (ZR1), the method comprising the following steps: - Considering each pressure sensor of 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 taken into account over a first period of time, b) determining (108) an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining (114, 116, 118, 120) the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor taken into account and the capacitive values measured over a subsequent period of time by the pressure sensor taken into account arranged in that zone, - generating a warning signal when an absence of pressure on the first front zone or on the second front zone has been determined, the generated warning signal being representative of a position of a leg of the seat occupant crossed over the other leg. [9] A method for detecting an unfavorable posture of an occupant sitting on a seat (2) of a vehicle, in particular a motor vehicle; wherein the seat (2) has a seat surface (4) and a backrest (6) hinged to the seat surface, wherein the backrest (6) comprises two side edges (8, 10), wherein a first vertical center plane ((X1 Z1)) extends between the two side edges and in the middle between them; wherein the method is implemented by a detection system (15) comprising a processor (16), at least one first pressure sensor (18) arranged in a first zone (Z1) on one side of the first vertical center plane ((X1, Z1)), and a second pressure sensor (20) arranged in a second zone (Z2) located on the other side of the first vertical center plane ((X1, Z1));wherein the method comprises a step (100) of activating a measurement phase comprising periods during which capacitive values are measured by the first and second pressure sensors; wherein the method further comprises the following steps, implemented by the processor during the measurement phase: - upon detection (102) of the presence of an occupant on the seat, activating (104) a clock suitable for signalling the end of a first defined period (D1); - after the first defined duration (D1), Considering each pressure sensor of 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 taken into account over a first period of time, b) determining (108) an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining (114, 116, 118, 120) the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor taken into account and the capacitive values measured over a subsequent period of time by the pressure sensor taken into account arranged in that zone, - generating (124) a warning signal when an absence of pressure on at least one of the first zone (Z1) and the second zone (Z2) has been determined. [10] Method for detecting an unfavorable posture of an occupant sitting on a seat (2) of a vehicle, in particular a motor vehicle; wherein the seat (2) has a seat surface (4) and a backrest (6) hinged to the seat surface, wherein the backrest (6) comprises an upper edge (12) and a lower edge (14) adjacent to the seat surface; wherein a horizontal center plane ((XY)) extends midway between the upper edge (12) and the lower edge (14); wherein the method is 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 center plane ((X,Y)), and a second pressure sensor (20) arranged in a second zone (Z2) located below the horizontal center plane ((X,Y));wherein the method comprises a step (100) of activating a measurement phase comprising periods during which capacitive values are measured by the first (18) and second (20) pressure sensors; wherein the method further comprises the following steps, implemented by the processor during the measurement phase: - upon detection (102) of the presence of an occupant on the seat, activating (104) a clock suitable for signalling the end of a first defined period (D1); - after the first defined duration (D1), Considering each pressure sensor of 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 taken into account over a first period of time, b) determining (108) an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining (114, 116, 118, 120) the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor taken into account and the capacitive values measured over a subsequent period of time by the pressure sensor taken into account arranged in that zone, - generating (124) a warning signal when an absence of pressure on at least one of the first zone and the second zone has been determined. [11] Method for detecting an unfavorable body posture according to one of claims 9 and 10, wherein the seat surface (4) comprises a front edge (26) and a rear edge (28), wherein a vertical transverse plane (Y, Z) is defined between and midway between the front edge (26) of the seat surface and the rear edge (28) of the seat surface, the detection device (15) comprises at least a first front pressure sensor (30) arranged in a front zone (ZA) of the seat surface located in front of the vertical transverse plane (Y, Z), and a first rear pressure sensor (32) arranged in a rear zone (ZR) of the seat surface located behind the vertical transverse plane (Y, Z), the method comprising the following steps: - Considering each pressure sensor of 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 taken into account over a first period of time, b) determining (108) an allowable range of variation defined for the sensor considered based on the characteristic value, c) determining (114, 116, 118, 120) the presence or absence of pressure on a zone on the basis of the permissible range of variation defined for the sensor taken into account and the capacitive values measured over a subsequent period of time by the pressure sensor taken into account arranged in that zone, - generating a warning signal (124) when an absence of pressure on the rear zone has been determined, the generated warning signal being representative of a forwardly displaced pelvic position of the seat occupant.

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