FR2871118A1 - Seat unit e.g. base, occupation characterization system for motor vehicle, has seat with outer face having frontier portion including sensors creating signal indicating occupant presence, and microprocessor to create occupation cartography - Google Patents

Abstract

The system has a seat with an outer face having a frontier portion (13) between a free portion (14) and an occupation portion (12). The frontier portion has occupant presence sensors (21a-21c), each generating a signal representative of a presence at a level of the sensor. A microprocessor (20) detects the signal and generates cartography of occupation of a seat unit such as base. The occupation portion corresponds to a predefined support surface for an occupant or an object intended to take place on the seat. The occupant is a driver of average weight or size, adult or infant, and the object is a heavy object. Independent claims are also included for the following: (A) a method to characterize occupation of a seat unit of a motor vehicle (B) a seat unit of a motor vehicle.

Description

System and method for occupation characterization

  The present invention relates to systems and methods for characterizing the occupancy of a vehicle seat element, and to seat elements for such a system. .

  In particular, the invention relates to a system for characterizing the occupancy of a motor vehicle seat element comprising: a vehicle seat element comprising an outer face with a portion of occupation corresponding to a predefined surface; support for an occupant or an object intended to take place on the seat element and whose shape is predetermined, a free portion distinct from the occupation portion, and a border portion between the free and occupied portions, and at least one presence sensor positioned in the seat element, each sensor generating a signal representative of a presence at this sensor, and means for processing the signals emitted by each of the sensors.

  For some time now, it has been proposed to detect the presence of an occupant of a car seat, for example to trigger the swelling of an inflatable safety bag in the event of an impact.

  WO00 / 25,098 describes an example of a seat provided with such seat elements with presence sensors facing characteristic areas for example at the legs, back, shoulders and head.

  Thus, such presence sensors have so far been placed directly in a seat occupation portion, the same one that is supposed to receive the occupant.

  These presence sensors generally make it possible to detect whether or not the seat is occupied, or even to estimate the weight of the occupant, or at best a postural parameter of the occupant. Nevertheless, problems arise when the seat element is provided with other devices in the occupying portion. For example, there are compatibility problems between a heating mat, placed in the occupation portion, and such presence sensors.

  The present invention is intended to at least partially overcome these disadvantages.

  For this purpose, according to the invention, there is provided a characterization system as described above essentially characterized in that at least the boundary portion is provided with at least one presence sensor.

  Thanks to these provisions, without compatibility problems, information is obtained on the occupation of portions of seats distinct from the portions normally occupied and on the shape of the bearing surface of the occupant or the object present on the seat. It can possibly be deduced that occupies the seat, be it a heavy object, a driver of height or average weight, a teenager or a child, etc. It is then possible, for example, to set up appropriate safety or comfort measures.

  In embodiments of the invention, one or more of the following provisions may also be used: the occupying portion and the free portion are also each provided with at least a presence sensor; the processing means are adapted to map the occupancy of the seat element; the system comprises at least two presence sensors, and each sensor comprises a first electrode and a second electrode, each first electrode being connected to the others to generate a signal representative of the occupation of the seat element, said sensors are capacitive sensors; the seat element further comprises a heating mat in the occupying portion; the processing means are adapted to determine, from the signals they receive, a class of seat occupants; .

  According to another aspect, the invention relates to a method for characterizing the occupation of a vehicle seat element comprising: an external face with a portion of occupation corresponding to a predefined bearing surface for an occupant or a an object intended to seat on the seat element and whose shape is predetermined, 25. a free portion distinct from the occupation portion, and a boundary portion between the free and occupied portions, and - at least one sensor of presence located in the seat element generating a signal representative of a presence at this sensor, and placed in the boundary portion, said vehicle comprising means for processing the signals emitted by each of the sensors to map the occupying the seat element, said method comprising steps in which (a) for each sensor, a signal representative of a presence in the seat a is detected, u level of this sensor, and (b) generates a map of occupation of the seat element.

  According to an embodiment of the method according to the invention, one can optionally also resort to the following provision: the generated map is compared to at least one seat occupant class model to deduce the possible belonging to the occupant or object to this class.

  According to another aspect, the invention relates to a vehicle seat element comprising: an outer face with a portion of occupation corresponding to a predefined bearing surface for an occupant or an object intended to take place on the element of seat and whose shape is predetermined, a free portion distinct from the occupation portion, and a boundary portion between the free portions and occupation, and - at least one presence sensor positioned in the seat member generating a signal representative of a presence at this sensor and placed in the boundary portion, and - connection means to signal processing means emitted by each of the sensors to map the occupation of the seat member.

  Other features and advantages of the invention will become apparent from the following description of one of its embodiments, given by way of non-limiting example, with reference to the accompanying drawings.

  In the drawings: - Figure 1 is a partially cutaway side view of a vehicle seat receiving an occupant; - Figure 2 is a detail view in perspective of a seat seat according to an embodiment of the FIG. 3 is a planar schematic view of a capacitive sensor that may be used in the context of the invention, FIG. 4 is a view from above of an example of sensor implantation according to FIG. invention, and - Figure 5 is a representative diagram of a central unit used in the context of the invention.

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

  FIG. 1 shows a side view of a vehicle 1, such as a motor vehicle comprising a seat 2 such as a single seat or a seat generally comprising a seat 3 and a backrest 4 possibly equipped with a headrest 4a, in which an occupant 5 can come to sit. The occupant 5, driver or passenger, usually has his legs arranged on the seat 3, while his back rests on the back 4, his head possibly resting on the headrest 4a.

  The seat 2, like the backrest 4, generally consists of a rigid structure (not shown) of the frame, tub, or other type, on which is deposited and fixed a padding 6 of the polyurethane foam type covered with a cap covering 7 of leather, textile, or other type. The backrest 4 generally has the same elements of padding 6 and cap 7.

  The seat can be directly mounted on the floor 8 of the vehicle, or by means of slides 9, one or more pairs of rods (not shown), or other.

  FIG. 2 is a perspective view of the upper external face 3a of a seat element, here the seat 3. This comprises, for example, a central cushion 10 arranged between two lateral flanges 11a, 11b, all made of polyurethane foam, covered with the covering cap 7 (not shown). 12 represents the portion of geometric occupation of the outer surface 3a of the seat 3 which is intended to be occupied by an occupant of average height and weight positioned in a normal position of occupation of the seat. This occupant corresponds for example to a predefined standard model (for example a man of 1 m 80 for 80 kg, or other) for which it predetermines a form of bearing surface on the seat member considered. The occupation portion is therefore also predetermined. For the purposes of understanding, this occupation portion 12 is delimited by the lines 13 representing the profile of the legs and the occupant's pelvis. The portion outside occupying portion 12, hereinafter called free portion 14 corresponds generally to the portion of the outer surface 3a of the seat 3 on which a seat occupant of size and average weight is not supposed to find in the normal position of occupation.

  Since all the occupants are not adults of average height and weight, it is also possible to geometrically define a border portion 15 (represented by small dots in FIG. 2) situated between, on the one hand, the lines 13 and the lines 16 substantially parallel to the bold lines 13, being "offset, outward" of a few millimeters to a few centimeters with respect thereto.

  A seating portion 12, a free portion 14 and a boundary portion 13 for a medium-sized adult occupant are thus defined geometrically for the seat. Of course, the same geometric cutting could be done for the backrest or headrest of the seat.

  In the context of the invention, it is sought to determine who of an adult occupant, a child, a heavy object, or other occupies the seat, in order to control the automatic regulation of certain comfort parameters of the vehicle, to adapt the safety parameters to the occupant actually present in the seat, or other. For this purpose, a series of sensors such as the capacitive sensor shown in FIG. 3 is placed in the seat 3 (the backrest 4, the headrest 4a, or the like). This type of sensor, of small extent, In particular, the surface of which is much smaller than that of an occupying portion 12, can be easily implanted between the cap 7 and the padding 6, or deeper into or under the padding of the seat. Such a capacitive sensor consists of a first electrode 17 for example in the form of a circular metal plate of about 1 centimeter radius on which is placed a second electrode 18 in the form for example of a circular wire d about 1/2 centimeter of radius isolated from each other by an insulator such as an insulating plastic sheath 19.

  In the seat or elsewhere, in the vehicle, there are processing means such as a central computing unit 20, for example in the form of a microprocessor adapted to generate potential differences between the electrodes 17, 18 of FIG. each sensor 21, so as to generate an electric field to the outside of the seat that can detect the exact location of the sensor 21 in the seat 3 the presence or not of something on the seat. Each sensor 21 is connected to the processing means 20 via connection means 20a.

  In the context of the invention, one could of course use all types of sensors allowing, in a very localized way, to detect the presence or not of something vertically of each of these sensors 21.

  Due to the presence or absence of something at the vertical of the sensor, the permittivity of the environment of the sensor is changed, and the signal measured at the output of the sensor in response to the excitation caused by the CPU 20 is relative the presence or absence of something at the sensor, that is to say the right of it or in its immediate vicinity.

  The signal is measured by a central unit, which is for example the same CPU 20 as the one transmitting the signals.

  Figure 4 now shows from above the seat 3 according to an illustrative mode of implantation of the sensors. The seat 3 is for example further provided with a heating sheet 22 (defined by the dashed lines 22a) extending mainly in the occupying portion of the seat.

  Three categories of sensors can be identified in FIG. 4. For example, the most central sensors 21a are located in occupying portion 12 relative to a seat occupant. The sensors 21b are located on the edges of the central cushion of the seat and are therefore located in the boundary portion 13, juxtaposing the heating web 22. Finally, the sensors 21c are located outside the boundary portion, in the portion free 14.

  According to one embodiment, the first electrodes 17 of each sensor are all interconnected, so that the signal generated towards the central unit 20 corresponds to the sum of the signals emitted by each of the first electrodes 17. This signal makes it possible to determine the presence or absence of something in the seat. In addition, the signals supplied by each of the second electrodes 18 independently reach the central unit 20, as explained now with reference to FIG. 5. As such, the central unit 20 comprises detection means 23 able to read the signals emitted by the various sensors 21a, 21b, 21c, calculation means 24 able to process the signals read by the detection means 23 from data relating to each sensor contained in a first memory 25 containing a or several weights relative to each sensor, recognition means 26 adapted to form, from calculations made by the calculation means 24, an "image" of what occupies the seat.

  There is also a second memory 27 comprising class models of typical things that can occupy the seat, such as for example an adult, a child, a baby seat, or other.

  During the process of characterizing the state of occupancy of the seat, during which a mapping of the seat is generated, the signals read by the detection means 23 are transmitted to the calculation unit 24 which applies to the different signals the weightings contained in the first memory means 25. These weightings are determined in advance depending, of course, on the position of the sensor in the seat, but also for example the nature of the materials of the padding, the cap, and electrostatic properties of the seat. The calculation made by the calculation unit 24 makes it possible to determine whether or not, or with what probability, something is directly vertical to a given sensor. This information is transmitted to the recognition unit 26 which compares the mapping established by the calculation unit 24 to a series of maps present in the second memory 27, and each corresponding for example to an occupant, to a child, to a teenager. , or other, as previously listed. If the recognition unit has made the link between the computed cartography and the models present in the second memory 27, it determines that an occupant, a child, a teenager, or other, is present in the seat. Otherwise, it concludes the presence for example of a heavy object in the seat, not necessarily requiring the release of an airbag in case of shock.

  By using only a very limited number of sensors in carefully selected locations to determine the nature of the occupant of the seat, compatibility problems for example with heating sheets are minimized because the relevant information obtained is mainly obtained in places not occupied by a medium-sized adult occupant, and therefore where the heating mat is not placed.

  The number, the position of the sensors, as well as their distribution in the occupation portions, free or border, depends on the type of seat (front or rear seat), the type of seat element (seat, backrest, armrest, support -tête), areas of the seat element that are to be probed in relation to the functions of the equipment using the occupancy information (a side airbag does not require a symmetrical distribution of the sensors in a seat), etc. . The mapping accessible through the information from the sensors can therefore be only partial with respect to the entire seat element in which the sensors are located.

Claims (10)

  A system for characterizing the occupancy of a motor vehicle seat element, comprising: a vehicle seat element having an outer face (3a) with a occupying portion (12) corresponding to a predefined surface of support for an occupant or an object intended to seat on the seat element and whose shape is predetermined, a free portion (14) separate from the occupation portion (12), and a boundary portion (13) between the free portions (14) and occupation (12), and - at least one presence sensor (21,21a, 21b, 21c) positioned in the seat member, each sensor (21,21a, 21b, 21c) generating a signal representative of a presence at this sensor, and - processing means (20) of the signals emitted by each of the sensors, characterized in that at least the boundary portion (13) is provided with minus a presence sensor (21b).   2. System according to claim 1, wherein the occupation portion (12) and the free portion (14) are also each provided with at least one presence sensor (21a, 21c).   3. System according to claim 1 or claim 2, wherein the processing means (20) are adapted to map the occupation of the seat element.   4. System according to one of the preceding claims, comprising at least two presence sensors, and wherein each sensor (21) comprises a first electrode and a second electrode, each first electrode being connected to the others to generate a signal representative of the occupation of the seat element.   5. System according to one of the claims   previous, wherein said sensors (21) are capacitive sensors.   6. System according to one of the preceding claims, wherein the seat member further comprises a heating web in the occupying portion (12).   7. System according to one of the preceding claims, wherein the processing means (20) are adapted to determine, from the signals they receive, a class of seat occupant.   8. A method of characterizing the occupancy of a vehicle seat element comprising: - an outer face (3a) with a occupying portion (12) corresponding to a predefined bearing surface for an occupant or an object intended to to seat on the seat member and whose shape is predetermined, a free portion (14) separate from the occupying portion (12), and a boundary portion (13) between the free portions (14) and d occupancy (12), and - at least one presence sensor (21,21a, 21b, 21c) positioned in the seat element generating a signal representative of a presence at that sensor, and placed in the boundary portion (13), said vehicle comprising means for processing (20) the signals emitted by each of the sensors in order to map the occupation of the seat element, this method comprising steps in which (a) for each sensor , a signal representative of a presence is detected in the seat at this sensor, and (b) generates a mapping occupation of the seat element.   The method of claim 8, wherein the generated map is compared to at least one seat occupant class model to infer whether the occupant or object belongs to that class.   10. Motor vehicle seat element, comprising: - an outer face (3a) with a occupying portion (12) corresponding to a predefined bearing surface for an occupant or an object intended to take place on the element of seat and whose shape is predetermined, a free portion (14) separate from the occupation portion (12), and 20. a boundary portion (13) between the free portions (15) and occupation (12), and at least one presence sensor (21, 21a, 21b, 21c) positioned in the seat element generating a signal representative of a presence at this sensor, and placed in the boundary portion (13), and connecting means (20a) to processing means (20) of the signals emitted by each of the sensors for mapping occupation of the seat element.