Method for detecting inappropriate posture of occupant sitting on vehicle seat

Abstract

The invention relates to a method for detecting an inappropriate posture of an occupant sitting on a seat of a vehicle, comprising the following steps:-after a first defined duration after detecting an occupant on the seat,-for each pressure sensor of a detection system: a) determining (106) a characteristic value, the characteristic value represents a capacitance value measured by the pressure sensor under consideration for a first time period, b) determining (108) an allowable variation range defined for the sensor under consideration on the basis of the characteristic value, c) determining (114, 116, 118, 120, 122) the absence of pressure on the region on the basis of the allowable variation range defined for the sensor under consideration and the capacitance value measured for a subsequent time period, and d) determining (114, 116, 118, 120, 122) the absence of pressure on the region on the basis of the allowable variation range defined for the sensor under consideration and the capacitance value measured for a subsequent time period. -generating (124) a warning signal when it is determined that there is no pressure on the at least one area.

Description

Field of the Invention

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

[0002] Object of the Invention

[0003] Preferably, a system for detecting an improper posture is proposed in order to inform the passenger on the seat that his position is unsafe or uncomfortable for driving and may ultimately lead to fatigue, pain in the muscles or back joints or neck pain.

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

[0005] The object of the present invention is a method for detecting an improper posture of an occupant sitting on a seat of a vehicle, in particular a motor vehicle; the seat having a seat base and a backrest hinged to the seat base, the backrest including two lateral edges, an upper edge and a lower edge adjacent to the seat base; a first vertical central plane extending between and in the middle of the two lateral edges, a first horizontal central plane extending between and in the middle of the upper edge and the lower edge; the method being implemented by a detection system including a processor, at least a first pressure sensor, a second pressure sensor, a third pressure sensor, a fourth pressure sensor, the first pressure sensor being arranged on a first area located on one side of the first vertical central plane and above the first horizontal central plane, the second pressure sensor being arranged on a second area located on the other side of the first vertical central plane and above the first horizontal central plane, the third pressure sensor being arranged on a third area located on the said one side of the first vertical central plane and below the first horizontal central plane, the fourth pressure sensor being arranged on a fourth area located on the said other side of the first vertical central plane and below the first horizontal central plane; the method including the step of activating a measurement phase, the measurement phase including a time period during which capacitance values are measured by the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor; the method further including the following steps performed by the processor during the measurement phase:

[0006] - When an occupant is detected on the seat, activating a clock suitable for emitting a signal indicating the end of a first defined duration;

[0007] - After the first defined duration, considering each of the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor,

[0008] - For each considered pressure sensor:

[0009] a) Determine an eigenvalue that represents a capacitance value measured by the pressure sensor under consideration during a first time period.

[0010] b) Based on the eigenvalue, determine a permitted variation range defined for the sensor under consideration.

[0011] c) Based on the permitted variation range defined for the sensor under consideration and the capacitance value measured by the sensor under consideration arranged in the area during a subsequent time period, determine the presence or absence of pressure on the area.

[0012] - When it is determined that there is no pressure on at least one area in the area under consideration, generate a warning signal.

[0013] The features disclosed in the following paragraphs can be implemented selectively. They can be implemented independently of each other or in combination with each other:

[0014] - The step of determining the presence or absence of pressure on the area includes the following steps:

[0015] i) Determine a subsequent eigenvalue that represents a capacitance value measured by the pressure sensor under consideration during a subsequent time period.

[0016] ii) Compare the subsequent eigenvalue with the permitted variation range defined for the sensor under consideration;

[0017] iii) If the subsequent eigenvalue is not within the permitted variation range defined for the sensor under consideration, determine that there is no pressure on the area under consideration, or when the subsequent eigenvalue is indeed within the permitted variation range defined for the sensor under consideration, determine that there is pressure on the area.

[0018] - The method further includes repeating steps i) to iii) within a second defined duration, and wherein the step of generating the warning signal is only implemented if the duration of continuously determining the absence of pressure is at least equal to the second defined duration.

[0019] - If it is determined that there is pressure on the first area and the second area, and it is determined that there is no pressure on the third area and the fourth area, the generated warning signal indicates the forward pelvic position of the seat occupant.

[0020] - If it is determined that there is no pressure on the first area and the third area, and it is determined that there is pressure on the second area and the fourth area, the generated warning signal indicates the position of the torso turning to the side.

[0021] - If it is determined that there is no pressure on the first area and the second area, and it is determined that there is pressure on the third area and the fourth area, the generated warning signal indicates the forward position of the seat occupant.

[0022] - The seat base 4 includes a front edge and a rear edge,

[0023] A vertical transverse plane is defined midway between the front edge of the seat base and the rear edge of the seat base,

[0024] The detection device includes at least a first front pressure sensor and a first rear pressure sensor. The first front pressure sensor is arranged on the front area of the seat base in front of the vertical transverse plane, and the first rear pressure sensor is arranged on the rear area of the seat base behind the vertical transverse plane; The method includes the following steps:

[0025] - Considering each pressure sensor among the first front pressure sensor and the first rear pressure sensor,

[0026] For each considered sensor:

[0027] a) Determine an eigenvalue that represents the capacitance value measured by the considered pressure sensor during a first time period,

[0028] b) Based on the eigenvalue, determine an allowable variation range defined for the considered sensor,

[0029] c) Based on the allowable variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the area during a subsequent time period, determine the presence or absence of pressure on the area,

[0030] - Generate a warning signal when it is determined that there is no pressure on the rear area. The generated warning signal indicates the pelvic anterior tilt position of the seat occupant.

[0031] The seat includes two lateral edges, and a second vertical center plane is defined midway between the two lateral edges of the seat base,

[0032] The front area includes a first front area of the seat base arranged on one side of the second vertical center plane and a second front area of the seat base arranged on the other side of the second vertical center plane,

[0033] The rear area includes a first rear area of the seat base located on one side of the second vertical center plane and a second rear area of the seat base located on the other side of the second vertical center plane,

[0034] The detection device includes a second front pressure sensor arranged on the second front area, and the first front pressure sensor is located on the first front area,

[0035] The detection device further includes a second rear pressure sensor arranged on the second rear area, and the first rear pressure sensor is located on the first rear area,

[0036] The method includes the following steps:

[0037] - Consider each of the second front pressure sensor and the second rear pressure sensor,

[0038] For each sensor considered:

[0039] a) Determine an eigenvalue that represents the capacitance value measured by the considered pressure sensor during a first time period,

[0040] b) Based on the eigenvalue, determine a permitted variation range defined for the considered sensor,

[0041] c) Based on the permitted variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the area during a subsequent time period, determine the presence or absence of pressure on the area,

[0042] - When it is determined that there is no pressure on the first front area or the second front area, generate a warning signal, and the generated warning signal indicates the position where a leg of the seat occupant is crossed over the other leg.

[0043] The present invention also relates to A): A method for detecting an improper posture of an occupant sitting on a seat of a vehicle, in particular a motor vehicle; the seat has a seat base and a backrest hinged to the seat base, the backrest includes two lateral edges, and a first vertical central plane extends between and in the middle of the two lateral edges; the method is implemented by a detection system, the detection system includes a processor, at least a first pressure sensor and a second pressure sensor, the first pressure sensor is arranged on a first area located on one side of the first vertical central plane, and the second pressure sensor is arranged on a second area located on the other side of the first vertical central plane; the method includes the step of activating a measurement phase, the measurement phase includes a time period during which the first pressure sensor and the second pressure sensor measure capacitance values; the method further includes the following steps executed by the processor during the measurement phase:

[0044] - When it is detected that there is an occupant on the seat, activate a clock suitable for emitting an end signal of a first defined duration;

[0045] - After the first defined duration,

[0046] Consider each of the first pressure sensor and the second pressure sensor,

[0047] For each sensor considered:

[0048] a) Determine an eigenvalue that represents the capacitance value measured by the considered pressure sensor during a first time period,

[0049] b) Based on the eigenvalue, determine a permitted variation range defined for the considered sensor,

[0050] c) Determine the presence or absence of pressure on the area based on the allowable variation range defined for the considered sensor and the capacitance values measured by the considered sensor arranged in the area during a subsequent time period.

[0051] - Generate a warning signal when it is determined that there is no pressure on at least one of the first area and the second area.

[0052] The present invention also relates to B): A method for detecting an improper posture of an occupant sitting on a seat of a vehicle, in particular a motor vehicle; the seat has a seat base and a backrest hinged to the seat base, the backrest includes an upper edge and a lower edge adjacent to the seat base; a horizontal center plane extends between the upper edge and the lower edge; the method is implemented by a detection system, the detection system includes a processor, at least a first pressure sensor and a second pressure sensor, the first pressure sensor is arranged on a first area above the horizontal center plane, and the second pressure sensor is arranged on a second area below the horizontal center plane; the method includes the step of activating a measurement phase, the measurement phase includes a time period during which the capacitance values are measured by the first pressure sensor and the second pressure sensor; the method further includes the following steps executed by the processor during the measurement phase:

[0053] - When it is detected that there is an occupant on the seat, activate a clock suitable for issuing an end signal of a first defined duration.

[0054] - After the first defined duration, consider each of the first pressure sensor and the second pressure sensor.

[0055] For each considered pressure sensor:

[0056] a) Determine an eigenvalue that represents the capacitance values measured by the considered pressure sensor during a first time period.

[0057] b) Based on the eigenvalue, determine the allowable variation range defined for the considered sensor.

[0058] c) Determine the presence or absence of pressure on the area based on the allowable variation range defined for the considered sensor and the capacitance values measured by the considered sensor arranged in the area during a subsequent time period.

[0059] - Generate a warning signal when it is determined that there is no pressure on at least one of the first area and the second area.

[0060] According to an embodiment, in the detection method according to (A) and (B), the step of determining the presence or absence of pressure on the area includes the following steps:

[0061] i) Determine a subsequent eigenvalue that represents a capacitance value measured by the pressure sensor under consideration during a subsequent time period.

[0062] ii) Compare the subsequent eigenvalue with the defined allowable variation range for the sensor under consideration.

[0063] iii) If the subsequent eigenvalue is not within the defined allowable variation range for the sensor under consideration, determine that there is no pressure on the area under consideration, or when the subsequent eigenvalue is indeed within the allowable variation range defined for the sensor under consideration, determine that there is pressure on the area.

[0064] - According to one embodiment, in the detection method according to (A) and (B), it further includes repeating steps i) to iii) within a second defined duration, and wherein the step of generating a warning signal is only implemented if it is continuously determined that there is no pressure or the duration of the presence of pressure is at least greater than the second defined duration.

[0065] In the detection method according to A), if it is determined that there is no pressure in the first area and there is pressure in the second area, the generated warning signal indicates the position where the torso turns to the side.

[0066] According to one embodiment, in the detection method according to B), if it is determined that there is no pressure in the first area and the second area, the generated warning signal indicates the forward-leaning position of the seat occupant.

[0067] According to one embodiment, in the detection methods according to A) and B), the seat base includes a front edge and a rear edge.

[0068] A vertical transverse plane is defined between and in the middle of the front edge of the seat base and the rear edge of the seat base.

[0069] The detection device includes at least a first front pressure sensor and a first rear pressure sensor. The first front pressure sensor is arranged on the front area of the seat base located in front of the vertical transverse plane, and the first rear pressure sensor is arranged on the rear area of the seat base located behind the vertical transverse plane; the method includes the following steps:

[0070] - Consider each pressure sensor among the first front pressure sensor and the first rear pressure sensor.

[0071] - For each sensor under consideration:

[0072] a) Determine an eigenvalue that represents a capacitance value measured by the pressure sensor under consideration during a first time period.

[0073] b) Based on the eigenvalue, determine the defined allowable variation range for the sensor under consideration.

[0074] c) Determine the presence or absence of pressure on the area based on the allowable variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the area during a subsequent time period.

[0075] - Generate a warning signal when it is determined that there is no pressure on the area after determination. The generated warning signal indicates the forward tilted position of the pelvis of the seat occupant.

[0076] According to one embodiment, in the detection method according to A) and B), the seat base includes two lateral edges, and a second vertical central plane is defined in the middle of the two lateral edges of the seat base.

[0077] The front area includes a first front area of the seat base arranged on one side of the second vertical central plane and a second front area of the seat base arranged on the other side of the second vertical central plane.

[0078] The rear area includes a first rear area of the seat base located on one side of the second vertical central plane and a second rear area of the seat base located on the other side of the second vertical central plane.

[0079] The detection device includes a second front pressure sensor arranged on the second front area, and a first front pressure sensor is located on the first front area.

[0080] The detection device further includes a second rear pressure sensor arranged on the second rear area, and a first rear pressure sensor is located on the first rear area.

[0081] The method includes the following steps:

[0082] - Consider each pressure sensor among the second front pressure sensor and the second rear pressure sensor.

[0083] - For each considered sensor:

[0084] a) Determine an eigenvalue that represents the capacitance value measured by the considered pressure sensor during a first time period.

[0085] b) Based on the eigenvalue, determine the allowable variation range defined for the considered sensor.

[0086] c) Based on the allowable variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the area during a subsequent time period, determine the presence or absence of pressure on the area.

[0087] - When it is determined that there is no pressure on the first front area or the second front area, generate a warning signal. The generated warning signal indicates the position where one leg of the seat occupant is crossed over the other leg. Description of the Drawings

[0088] Figure 1 is a schematic perspective view of a seat and a detection system according to a first embodiment of the present invention;

[0089] Figure 2 is Figure 1 a schematic perspective view of a part of a seat and a detection system that can be added to the detection system shown;

[0090] Figure 3 is a schematic diagram of the steps of a detection method according to the present invention;

[0091] Figure 4 is a schematic perspective view of a seat and a detection system according to a second embodiment;

[0092] Figure 5 is a schematic perspective view of a seat and a detection system according to a third embodiment;

[0093] Figure 6 is a schematic perspective view of a seat and a detection system according to a fourth embodiment. Detailed Description of the Invention

[0094] In this patent application, identical or similar elements have the same reference numerals and will not be described repeatedly.

[0095] In this application, the terms "upper", "lower", "in front of", "behind", "front part", and "rear part" shall be interpreted with respect to the normal position of a motor vehicle seat. The front part of the vehicle seat corresponds to the front part of the vehicle considering the normal driving direction of the vehicle.

[0096] In this application, the longitudinal direction X represents the horizontal direction extending between the front part and the rear part of the vehicle seat. The lateral direction Y represents the horizontal direction extending from one side of the seat to the other side of the seat. The vertical direction Z represents the direction perpendicular to the longitudinal direction X and the lateral direction Y.

[0097] The motor vehicle seat 2 includes a seat base 4 and a backrest 6 hinged to the seat base 4.

[0098] Referring to Figure 1 , the backrest 6 includes two lateral edges 8, 10, an upper edge 12, and a lower edge 14 adjacent to the seat base.

[0099] For this patent application, a first vertical central plane (X1, Z1) is defined, which extends between and in the middle of the two lateral edges 8, 10, and a first horizontal central plane (X, Y) is defined, which extends between and in the middle of the upper edge 12 and the lower edge 14 of the backrest.

[0100] The said plane defines four regions on the backrest. ​​​​​​

[0101] Specifically, the first region Z1 is located on one side of the first vertical central plane (X1, Z1) and above the first horizontal central plane (X, Y). The second region Z2 is located on the other side of the first vertical central plane (X1, Z1) and above the first horizontal central plane (X, Y).

[0102] The third region Z3 is located on the said side of the first vertical central plane (X1, Z1) and below the first horizontal central plane (X, Y). The fourth region Z4 is located on the said other side of the first vertical central plane (X1, Z1) and below the first horizontal central plane (X, Y).

[0103] The detection method according to the first embodiment is implemented by the detection system 15 according to the first embodiment, which detection system 15 includes a processor 16 and at least four pressure sensors arranged on the backrest.

[0104] See Figure 1 , the sensors arranged on the backrest include a first pressure sensor 18 arranged on the first region Z1 of the backrest, a second pressure sensor 20 arranged on the second region Z2 of the backrest, a third pressure sensor 22 arranged on the third region Z3 of the backrest, and a fourth pressure sensor 24 arranged on the fourth region Z4 of the backrest.

[0105] According to an advantageous and non - limiting variant, the detection method according to the first embodiment is implemented by a detection system 15, which detection system 15 further includes four pressure sensors on the seat base.

[0106] In particular, see Figure 2 , the seat base 4 includes a front edge 26, a rear edge 28 and two lateral edges 33, 36.

[0107] For the purposes of this patent application, a vertical transverse plane (Y, Z) is defined, which is located midway between the front edge 26 of the seat base and the rear edge 28 of the seat base, and a second vertical central plane (X2, Z2) is defined, which is located midway between the two lateral edges 33, 36 of the seat base.

[0108] The seat base 4 includes a front region ZA in front of the vertical transverse plane (Y, Z), and a rear region ZR behind the vertical transverse plane (Y, Z). Specifically, the seat base includes a first front region ZA1 of the seat base on one side of the second vertical central plane (Y, Z), and a second front region ZA2 of the seat base on the other side of the second vertical central plane (Y, Z). Similarly, the rear region ZR of the seat base 4 includes a first rear region ZR1 on one side of the second vertical central plane (Y, Z), and a second rear region ZR2 on the other side of the second vertical central plane (Y, Z).

[0109] See Figure 2 , the sensors located on the seat base include a first front pressure sensor 30 located on the first front area ZA1 of the seat base, a second front pressure sensor 34 located on the second front area ZA2, a first rear pressure sensor 32 located on the first rear area ZR1, and a second rear pressure sensor 37 located on the second rear area ZR2.

[0110] The pressure sensor is, for example, a capacitive sensor with coplanar cross electrodes, as described in the patent application numbered FR 3 126776.

[0111] Reference Figure 3 , the method for detecting improper postures begins with the step 100 of activating the measurement phase. During the measurement phase, the capacitance values generated by the pressure sensors 18 to 24 are measured at fixed time intervals. The measurement phase includes a time period during which multiple measurements are made. The measurement phase is continuously implemented in all steps of the method. Steps 114 to 124 are repeated using the new capacitance values measured during the measurement phase.

[0112] Then, the method includes the step 102 of detecting whether there is an occupant on the seat. This step can be performed using the capacitance values measured according to known procedures or by other means (such as cameras and image recognition systems). Once a passenger is detected on the seat, a clock is started in step 104. The clock is configured to emit a signal indicating the end of a first defined duration D1.

[0113] Then, after the first defined duration, each of the first, second, third, and fourth pressure sensors is considered.

[0114] Steps 106 to 122 are performed for each considered pressure sensor.

[0115] In step 106, a characteristic value representing the capacitance value generated by each considered pressure sensor is determined. The characteristic value represents the capacitance values measured during a first time period. The first time period is the first time period after the first defined duration D1. The characteristic value is, for example, the average of the capacitance values measured during the first time period. Alternatively, the characteristic value is the median of the capacitance values measured during the first time period.

[0116] In step 108, an allowable variation range defined for the considered sensor is determined. The allowable variation range is determined based on the characteristic value. For example, the lower limit value of the allowable variation range is equal to the characteristic value minus 15% of the characteristic value, while the upper limit value of the allowable variation range is equal to the characteristic value plus 15% of the characteristic value.

[0117] According to another example, the lower limit value of the allowable variation range is equal to the eigenvalue minus 20% of the eigenvalue, and the upper limit value of the allowable variation range is equal to the eigenvalue plus 20% of the eigenvalue.

[0118] In step 110, the allowable variation range defined in step 108 is stored in the memory of the processor 16.

[0119] In step 112, the method returns to step 106, considers another pressure sensor, and performs steps 106 to 110 on this other sensor. Thus, steps 106 to 110 are performed on each pressure sensor.

[0120] During steps 114 to 122, each region is considered, and it is determined whether there is pressure on each considered region based on the capacitance values measured by the pressure sensors arranged in the considered region. The considered regions are the first region Z1, the second region Z2, the third region, and the fourth region Z4 of the backrest, and the first front region ZA1, the second front region ZA2, the first rear region ZR1, and the second rear region ZR2 of the seat base.

[0121] In step 114, a next eigenvalue is determined based on the capacitance values generated by the considered pressure sensor in a subsequent time period. This subsequent eigenvalue represents the capacitance values measured in the subsequent time period. In the present patent application, the "subsequent time period" refers to the time period immediately following the first time period and all subsequent time periods. During the duration of the entire measurement phase, step 114 will be repeated for each new time period. This subsequent eigenvalue is, for example, the average value of the capacitance values measured during the subsequent time period. Alternatively, the subsequent eigenvalue is the median of the capacitance values measured during the subsequent time period.

[0122] In step 116, the subsequent eigenvalue is compared with the allowable variation range defined for the considered sensor and stored in the memory of the processor.

[0123] When the subsequent eigenvalue is within the allowable variation range, it is determined in step 118 that there is pressure in the considered region. If the subsequent eigenvalue is outside the allowable variation range, it is determined in step 118 that there is no pressure in the considered region.

[0124] Steps 114 to 118 are repeated for all pressure sensors in step 120.

[0125] Preferably, the method includes step 122, during which steps 114 to 118 are repeatedly executed based on the capacitance values generated by the pressure sensor in a subsequent time period. These steps 114 to 118 are repeated multiple times during a duration of at least equal to the second defined duration D2. And steps 123 and 124 are only executed when no pressure is detected during the second defined duration.

[0126] Then, in step 123, analyze the sets of states with pressure present and pressure absent to determine whether the position of the occupant of the seat on the seat is inappropriate.

[0127] In step 124, when it is determined that there is no pressure on at least one of the areas under consideration, a warning signal is generated.

[0128] Specifically, if it is determined that there is pressure in the first area Z1 and the second area Z2, and it is determined that there is no pressure in the third area Z3 and the fourth area Z4, the generated warning signal indicates the position of the pelvic tilt forward of the seat occupant.

[0129] In addition to the four sensors on the backrest, when the seat also includes four sensors on the seat base, by determining that there is no pressure on the first rear area ZR1 according to the capacitance value measured by the first rear pressure sensor 32, and by determining that there is no pressure on the second rear area ZR2 according to the capacitance value measured by the second rear pressure sensor 37, the warning signal indicating the position of the pelvic tilt forward of the seat occupant can be confirmed.

[0130] When it is determined that there is no pressure on the first area Z1 and the third area Z3, and it is determined that there is pressure on the second area Z2 and the fourth area Z4, the generated warning signal indicates the position of the torso turning to the side.

[0131] When it is determined that there is no pressure on the second area Z2 and the fourth area Z4, and it is determined that there is pressure on the first area Z1 and the third area Z3, the generated warning signal also indicates the position of the torso turning to the side.

[0132] When it is determined that there is no pressure on the first area Z1 and the second area Z2, and it is determined that there is pressure on the third area Z3 and the fourth area Z4, the generated warning signal indicates the forward position of the seat occupant.

[0133] When it is determined that there is no pressure on the first front area ZA1 or the second front area ZA2, the generated warning signal indicates the position where one leg of the seat occupant is crossed over the other leg.

[0134] In step 126, the warning signal can be transmitted to a display device to display an image corresponding to the type of detected inappropriate posture. Alternatively, the warning signal is transmitted to an audio system that emits a sound alert or a voice system that can select a voice message corresponding to the type of detected inappropriate posture.

[0135] Figure 4Shows a detection system according to a second embodiment, which can implement the detection method according to the present invention. In this second embodiment, the detection system 15 includes a processor 16, at least a first pressure sensor 18 and a second pressure sensor 20. The first pressure sensor is arranged on a first area Z1 on one side of the first vertical central plane (X1, Z1), and the second pressure sensor is arranged on a second area Z2 on the other side of the first vertical central plane (X1, Z1). The first vertical central plane (X1, Z1) is defined as Figure 1 the first vertical central plane (X1, Z1) shown in

[0136] Steps 100 to 124 of the detection method according to the present invention can be implemented by the detection system according to the second embodiment.

[0137] In particular, the detection system according to the second embodiment includes a step for determining the presence or absence of pressure on the area. This step includes the following steps:

[0138] i) Determine 114 subsequent eigenvalue, which represents the capacitance value measured by the pressure sensor under consideration during a subsequent time period,

[0139] ii) Compare 116 the subsequent eigenvalue with the defined allowable change range for the sensor under consideration;

[0140] iii) If the subsequent eigenvalue is not within the defined allowable change range for the sensor under consideration, determine 118 that there is no pressure on the area under consideration, or if the subsequent eigenvalue is indeed within the allowable change range defined for the sensor under consideration, determine that there is pressure on the area under consideration.

[0141] The method for detecting an inappropriate posture implemented by the second detection system further includes step 122, that is, repeating steps i) to iii) within a second defined duration D2. The step of generating a warning signal is only implemented if the duration of continuously determining the absence of pressure or the presence of pressure is greater than the second defined duration.

[0142] In this embodiment, when it is determined that there is no pressure in the first area Z1 and there is pressure in the second area Z2, the generated warning signal indicates a position where the torso turns to the side.

[0143] Preferably, the detection device 15 according to the second embodiment further includes a first front pressure sensor 30 and a first rear pressure sensor 32, as Figure 6 shown. The first front pressure sensor 30 is arranged on the front area ZA of the seat base in front of the vertical lateral plane (Y, Z). The first rear pressure sensor 32 is arranged on the rear area ZR of the seat base behind the vertical lateral plane (Y, Z). The vertical lateral plane (Y, Z) is defined and positioned in the same way asFigure 1 is the same as the vertical lateral plane (Y, Z) shown.

[0144] When there is no pressure on the rear area ZR, the generated warning signal indicates the forward pelvic position of the seat occupant.

[0145] Alternatively, the detection device 15 according to the second embodiment further includes four pressure sensors, as Figure 1 shown, which are arranged on the seat base.

[0146] In this case, the seat base 4 includes two lateral edges 33, 36. The second vertical center plane (X2, Z2) is defined in the middle of the two lateral edges of the seat base. The front area ZA includes a first front area ZA1 of the seat base arranged on one side of the second vertical center plane (Y, Z) and a second front area ZA2 of the seat base arranged on the other side of the second vertical center plane (Y, Z),

[0147] The rear area ZR includes a first rear area ZR1 of the seat base located on one side of the second vertical center plane (Y, Z) and a second rear area ZR2 of the seat base located on the other side of the second vertical center plane (Y, Z).

[0148] The detection device 15 includes a second front pressure sensor 34 arranged on the second front area ZA2, while the first front pressure sensor 30 is located on the first front area ZA1.

[0149] The detection device 15 further includes a second rear pressure sensor 37 arranged on the second rear area ZR2, while the first rear pressure sensor 32 is located on the first rear area ZR1.

[0150] The detection method implemented by the second detection system includes the following steps:

[0151] Considering each of the second front pressure sensor 34 and the second rear pressure sensor 37,

[0152] - For each sensor considered:

[0153] a) Determine the 106 eigenvalue, which represents the capacitance value measured by the considered pressure sensor during the first time period,

[0154] b) Based on the eigenvalue, determine the 108 allowable variation range defined for the considered sensor,

[0155] c) Based on the allowable variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the area during the subsequent time period, determine 114, 116, 118, 120 whether there is pressure on the area,

[0156] - When it is determined that there is no pressure on the first front region ZA1 or the second front region ZA2, a warning signal 124 is generated, and the generated warning signal indicates the position where one leg of the seat occupant is crossed over the other leg.

[0157] Figure 5 A detection system according to a third embodiment is shown, which can implement the detection method according to the present invention. In this third embodiment, a horizontal central plane (X, Y) is defined. This horizontal central plane (X, Y) extends midway between the upper edge 12 and the lower edge 14 of the seat back. The detection system 15 according to the third embodiment includes a processor 16, a first pressure sensor 18 arranged on a first region Z1 above the first vertical central plane (X, Z), and a second pressure sensor 20 arranged on a second region Z2 below the first vertical central plane (X, Z).

[0158] Steps 100 to 124 of the detection method according to the present invention can be implemented by the detection system according to the second embodiment.

[0159] In particular, the detection system according to the second embodiment includes steps for determining whether there is pressure on a region. This step includes the following steps:

[0160] i) Determine a subsequent eigenvalue 114, which represents the capacitance value measured by the pressure sensor under consideration during a subsequent time period,

[0161] ii) Compare the subsequent eigenvalue with the defined allowable variation range for the sensor under consideration 116;

[0162] iii) If the subsequent eigenvalue is not within the defined allowable variation range for the sensor under consideration, determine 118 that there is no pressure on the region under consideration, or if the subsequent eigenvalue is indeed within the defined allowable variation range for the sensor under consideration, determine that there is pressure on the region.

[0163] The method for detecting an inappropriate posture implemented by the second detection system further includes step 122, that is, repeating steps i) to iii) within a second defined duration D2. The step of generating a warning signal is only implemented when the duration of continuously determining the absence or presence of pressure is greater than the second defined duration.

[0164] When it is determined that there is no pressure in the first region Z1 and the second region Z2, the generated warning signal indicates the forward leaning position of the seat occupant.

[0165] Preferably, the seat base 4 of the detection system according to the third embodiment includes two lateral edges 33, 36. A second vertical central plane (X2, Z2) is defined midway between the two lateral edges of the seat base.

[0166] The front region ZA includes a first front region ZA1 of the seat base located on one side of the second vertical central plane and a second front region ZA2 of the seat base located on the other side of the second vertical central plane (X2, Z2).

[0167] The rear region includes a first rear region ZR1 of the seat base located on one side of the second vertical central plane (X2, Z2) and a second rear region ZR2 of the seat base located on the other side of the second vertical central plane (X2, Z2).

[0168] The detection device 15 includes a second front pressure sensor 37 arranged on the second front region ZA2, while the first front pressure sensor 30 is located on the first front region ZA1.

[0169] The detection device 15 further includes a second rear pressure sensor 37 arranged on the second rear region ZR2, while the first rear pressure sensor 34 is located on the first rear region ZR1.

[0170] The detection method implemented by the detection system according to the third embodiment includes the following steps:

[0171] - Considering each pressure sensor among the second front pressure sensor 34 and the second rear pressure sensor 37,

[0172] - For each considered sensor:

[0173] a) Determine 106 the eigenvalue that represents the capacitance value measured by the considered pressure sensor within the first time period,

[0174] b) Based on the eigenvalue, determine 108 the allowable variation range defined for the considered sensor,

[0175] c) Based on the allowable variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the region within a subsequent time period, determine 114, 116, 118, 120 the presence or absence of pressure on the region,

[0176] - When it is determined that there is no pressure on the first front region AZ1 or the second front region ZA2, generate 124 a warning signal, and the generated warning signal indicates the position where one leg of the seat occupant is crossed over the other leg.

[0177] Alternatively, the detection system according to the fourth embodiment may include two pressure sensors, as Figure 6 shown.

[0178] Alternatively, the detection system according to another embodiment may include four pressure sensors, as Figure 1 shown.

Claims

1. A method for detecting an inappropriate posture of an occupant sitting on a seat (2) of a vehicle, in particular a motor vehicle; the seat (2) having a seat base (4) and a backrest (6) hinged to the seat base, the backrest (6) including two lateral edges (8, 10), an upper edge (12) and a lower edge (14) adjacent to the seat base; a first vertical central plane ((X1, Z1)) extending between and in the middle of the two lateral edges (8, 10), and a first horizontal central plane ((X, Y)) extending between and in the middle of the upper edge (12) and the lower edge (14); the method being implemented by a detection system (15) including a processor (16), at least a first pressure sensor (18), a second pressure sensor (20), a third pressure sensor (22), a fourth pressure sensor (24), the first pressure sensor being arranged on a first area (Z1) located on one side of the first vertical central plane ((X1, Z1)) and above the first horizontal central plane ((X, Y)), the second pressure sensor being arranged on a second area (Z2) located on the other side of the first vertical central plane ((X1, Z1)) and above the first horizontal central plane ((X, Y)), the third pressure sensor being arranged on a third area (Z3) located on the one side of the first vertical central plane ((X1, Z1)) and below the first horizontal central plane ((X, Y)), the fourth pressure sensor being arranged on a fourth area (Z4) located on the other side of the first vertical central plane ((X1, Z1)) and below the first horizontal central plane ((X, Y)); the method including the step (100) of activating a measurement phase, the measurement phase including a time period during which capacitance values are measured by the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor; the method further including the following steps executed by the processor during the measurement phase: - When detecting (102) the presence of an occupant on the seat, activating (104) a clock suitable for emitting an end signal of a first defined duration (D1); - After the first defined duration (D1), considering each of the first pressure sensor, the second pressure sensor, the third pressure sensor and the fourth pressure sensor, - For each considered pressure sensor: a) Determining (106) an eigenvalue representing the capacitance value measured by the considered pressure sensor within a first time period, b) Based on the eigenvalue, determining (108) a permitted variation range defined for the considered sensor, c) Based on the permitted variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the area within a subsequent time period, determining (114, 116, 118, 120, 122) the presence or absence of pressure on the area - When it is determined that there is no pressure on at least one of the regions under consideration, a warning signal is generated (124).

2. The method for detecting an inappropriate posture according to claim 1, wherein The step of determining the presence or absence of pressure on a region includes the following steps: i) Determine (114) a subsequent eigenvalue that represents the capacitance value measured by the pressure sensor under consideration during a subsequent time period, ii) Compare (116) the subsequent eigenvalue with the allowable change range defined for the sensor under consideration; iii) If the subsequent eigenvalue is not within the allowable change range defined for the sensor under consideration, determine (118) that there is no pressure on the region under consideration, or when the subsequent eigenvalue is indeed within the allowable change range defined for the sensor under consideration, determine that there is pressure on the region.

3. The method for detecting an inappropriate posture according to claim 2, further comprising repeating (122) steps i) to iii) within a second defined duration (D2), and wherein, The step of generating the warning signal is only implemented if the duration during which it is continuously determined that there is no pressure is at least equal to the second defined duration (D2).

4. The detection method according to any one of claims 1 to 3, characterized in that, If it is determined that there is pressure on the first region (Z1) and the second region (Z2), and it is determined that there is no pressure on the third region (Z3) and the fourth region (Z4), the generated warning signal indicates the anterior pelvic tilt position of the seat occupant.

5. The detection method according to any one of claims 1 to 3, characterized in that, If it is determined that there is no pressure on the first region (Z1) and the third region (Z3), and it is determined that there is pressure on the second region (Z2) and the fourth region (Z4), the generated warning signal indicates the position of the torso turned to the side.

6. The detection method according to any one of claims 1 to 3, characterized in that, If it is determined that there is no pressure on the first region (Z1) and the second region (Z2), and it is determined that there is pressure on the third region (Z3) and the fourth region (Z4), the generated warning signal indicates the anterior tilt position of the seat occupant.

7. The method for detecting an inappropriate posture according to any one of claims 1 to 6, characterized in that, The seat base (4) includes a front edge (26) and a rear edge (28), A vertical transverse plane (Y, Z) is defined midway between the front edge (26) of the seat base and the rear edge (28) of the seat base, The detection means (15) includes at least a first front pressure sensor (30) and a first rear pressure sensor (32), the first front pressure sensor being arranged on the front region (ZA) of the seat base in front of the vertical transverse plane (Y, Z), and the first rear pressure sensor being arranged on the rear region (ZR) of the seat base behind the vertical transverse plane (Y, Z); the method includes the following steps: - Consider each of the first front pressure sensor (30) and the first rear pressure sensor (32), For each sensor under consideration: a) Determine (106) an eigenvalue that represents the capacitance value measured by the pressure sensor under consideration during a first time period, b) Based on the eigenvalue, determine (108) the allowable change range defined for the sensor under consideration, c) Based on the allowable change range defined for the sensor under consideration and the capacitance value measured by the sensor under consideration arranged in the region during a subsequent time period, determine (114, 116, 118, 120, 122) the presence or absence of pressure on the region - Generate (124) a warning signal when it is determined that there is no pressure on the rear region (ZR), the generated warning signal indicating the forward pelvic position of the seat occupant.

8. The method for detecting an inappropriate posture according to claim 7, characterized in that The seat includes two lateral edges (33, 36), and a second vertical center plane (X2, Z2) is defined in the middle of the two lateral edges of the seat base. The front region (ZA) includes a first front region (ZA1) of the seat base arranged on one side of the second vertical center plane (Y, Z) and a second front region (ZA2) of the seat base arranged on the other side of the second vertical center plane (Y, Z). The rear region (ZR) includes a first rear region (ZR1) of the seat base located on one side of the second vertical center plane (Y, Z) and a second rear region (ZR2) of the seat base located on the other side of the second vertical center plane (Y, Z). The detection device (15) includes a second front pressure sensor (34) arranged on the second front region (ZA2), and the first front pressure sensor (30) is located on the first front region (ZA1). The detection device (15) further includes a second rear pressure sensor (37) arranged on the second rear region (ZR2), and the first rear pressure sensor (32) is located on the first rear region (ZR1). The method includes the following steps: - Consider each pressure sensor among the second front pressure sensor (34) and the second rear pressure sensor (37). For each considered sensor: a) Determine (106) an eigenvalue, the eigenvalue representing the capacitance value measured by the considered pressure sensor within a first time period. b) Based on the eigenvalue, determine (108) the allowable change range defined for the considered sensor. c) Based on the allowable change range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the region within a subsequent time period, determine (114, 116, 118, 120) whether there is pressure on the region. - When it is determined that there is no pressure on the first front region or the second front region, generate a warning signal, the generated warning signal indicating the position where one leg of the seat occupant is crossed over the other leg.

9. A method for detecting an inappropriate posture of an occupant sitting on a seat (2) of a vehicle, in particular a motor vehicle; said seat (2) having a seat base (4) and a backrest (6) hinged to said seat base, said backrest (6) comprising two lateral edges (8, 10), a first vertical central plane ((X1, Z1)) extending between and in the middle of said two lateral edges; the method being implemented by a detection system (15) comprising a processor (16), at least a first pressure sensor (18) and a second pressure sensor (20), said first pressure sensor being arranged in a first area (Z1) located on one side of said first vertical central plane ((X1, Z1)), said second pressure sensor being arranged in a second area (Z2) located on the other side of said first vertical central plane ((X1, Z1)); the method comprising a step (100) of activating a measurement phase, said measurement phase comprising a time period during which the capacitance values are measured by the first pressure sensor and the second pressure sensor; the method further comprising the following steps executed by the processor during said measurement phase: - When detecting (102) the presence of an occupant on the seat, activate (104) a clock suitable for emitting an end signal of a first defined duration (D1); - After said first defined duration (D1), Considering each of the first pressure sensor (18) and the second pressure sensor (20), For each considered sensor: a) Determine (106) an eigenvalue representing the capacitance value measured by the considered pressure sensor during a first time period, b) Based on said eigenvalue, determine (108) a permitted variation range defined for the considered sensor, c) Based on the permitted variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the area during a subsequent time period, determine (114, 116, 118, 120) the presence or absence of pressure on said area, - When it is determined that there is no pressure on at least one of the first area (Z1) and the second area (Z2), generate (124) a warning signal.

10. A method for detecting an inappropriate posture of an occupant sitting on a seat (2) of a vehicle, in particular a motor vehicle; the seat (2) having a seat base (4) and a backrest (6) hinged to the seat base, the backrest (6) including an upper edge (12) and a lower edge (14) adjacent to the seat base; a horizontal central plane ((X, Y)) extending midway between the upper edge (12) and the lower edge (14); the method being implemented by a detection system (15) including a processor (16), at least a first pressure sensor (18) and a second pressure sensor (20), the first pressure sensor being arranged in a first region (Z1) above the horizontal central plane ((X, Y)), and the second pressure sensor being arranged in a second region (Z2) below the horizontal central plane ((X, Y)); the method including a step (100) of activating a measurement phase, the measurement phase including a time period during which capacitance values are measured by the first pressure sensor (18) and the second pressure sensor (20); the method further including the following steps performed by the processor during the measurement phase: - When detecting (102) the presence of an occupant on the seat, activating (104) a clock adapted to emit a signal indicating the end of a first defined duration (D1); - After the first defined duration (D1), considering each of the first pressure sensor (18) and the second pressure sensor (20), For each considered pressure sensor: a) Determining (106) an eigenvalue representing the capacitance value measured by the considered pressure sensor during a first time period, b) Based on the eigenvalue, determining (108) a permitted variation range defined for the considered sensor, c) Based on the permitted variation range defined for the considered sensor and the capacitance value measured by the considered sensor arranged in the region during a subsequent time period, determining (114, 116, 118, 120) the presence or absence of pressure on the region, - When it is determined that there is no pressure on at least one of the first region and the second region, generating (124) a warning signal.

11. The method for detecting an inappropriate posture according to any one of claims 9 and 10, characterized in that, The seat base (4) includes a front edge (26) and a rear edge (28), A vertical lateral plane (Y, Z) is defined between and midway through the front edge (26) and the rear edge (28) of the seat base, The detection device (15) includes at least a first front pressure sensor (30) and a first rear pressure sensor (32), the first front pressure sensor being arranged in a front region (ZA) of the seat base in front of the vertical lateral plane (Y, Z), and the first rear pressure sensor being arranged in a rear region (ZR) of the seat base behind the vertical lateral plane (Y, Z), the method including the following steps: - Considering each of the first front pressure sensor (30) and the first rear pressure sensor (32), - For each considered sensor: a) Determine (106) an eigenvalue that represents a capacitance value measured by a pressure sensor under consideration during a first time period, b) Based on the eigenvalue, determine (108) a permitted variation range defined for the sensor under consideration, c) Based on the permitted variation range defined for the sensor under consideration and capacitance values measured by the sensor under consideration arranged in a region during a subsequent time period, determine (114, 116, 118, 120) whether there is pressure present or absent on the region, - Generate (124) a warning signal when it is determined that there is no pressure on the rear region, and the generated warning signal indicates a forward pelvic tilt position of the seat occupant.

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