Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
  • B60R21/01512—Passenger detection systems
  • B60R21/01516—Passenger detection systems using force or pressure sensing means

Definitions

• the invention relates to an apparatus for discriminating whether a person is on the seat surface of a vehicle seat be ⁇ or an object having at least one substantially flat supporting surface which is disposed over a large part of the seating surface including a central area.
• the device comprises a vehicle seat, a seat mat with weight sensors distributed in a planar manner on the seat surface of the vehicle seat, and an evaluation unit to which the signals of the weight sensors are fed.
• occupancy by occupants is an important input. This especially applies sat restraint systems for in ⁇ whose efficient, ie injury to persons avoidant, use of occupant restraint means is often dependent on the seating position of the occupant.
• an occupant restraining means associated with the respective vehicle seat generally has to be suppressed in the event of a vehicle accident, if a child seat, in particular a child seat directed backwards against the direction of travel, is recognized by the seat occupancy recognition.
• Systems for detecting the seat occupancy in a vehicle seat that use only the sensor signals of a sensor seat mat can often poorly example, a child seat different from a very light person, such as a so-called 5% woman, ie a woman who as a lighter and klei ⁇ ner than 95% of a representative peer group of women Is accepted.
• the release of particular airbag should be omitted, as this could injure a child in the child seat; in a 5% woman, however, the airbag should normally be triggered.
• transponders in a child seat and transmitting and receiving antennas in the vehicle seat on which the child seat has been mounted.
• the child seat can be clearly detected.
• Such an additional detection system for detecting an object on a vehicle seat makes an occupant protection system, however technically for expenditures ended, which is usually higher costs for an occupant protection system and the probability of default un ⁇ ter circumstances is increased.
• a person can be distinguished on a vehicle seat of a local subject, which - as in most child seats of the case - an at least partially planar support surface, when the seat of the vehicle seat is concave shaped concave in the direction of Fahr ⁇ zeugboden. Detection takes place with the aid of a sensor seat mat which extends both over the centrally concaved seat surface and into an area around this concave curvature.
• Object of the present invention is therefore to provide a simple alternative device and a simple alternative method for distinguishing whether a person is on the seat of a vehicle seat or a Ge ⁇ genstand with an at least largely flat Auflageflä ⁇ che, in particular a child seat.
• This object is achieved by an apparatus according to ⁇ demanding 1.
• This apparatus is for discriminating whether a person is on the seat surface of a vehicle seat or an object, in particular a child's seat, with Any artwork at least one largely flat bearing surface, which is arranged over a large part of the seat including a central area.
• the device comprises a seat mat with weight sensors distributed in a planar manner on the seat surface of the vehicle seat, with first weight sensors in the central area and second weight sensors in the area of the seat covered by the object outside the central area.
• at least one first weight sensor differs from a plurality of second weight sensors in that it outputs a sensor signal that is always lower than the measurement inaccuracy of the device within a weight range to be detected by the device for the same weight load.
• the weight range to be detected by the device is preferably a subarea of the weight-dependent characteristic curve of sensor values of at least one weight sensor with a preferably large, approximately linear gradient.
• the measurable signal difference of the thus different areal weight sensors and the edge weight sensors must be greater than the measurement inaccuracy resulting from the measuring electronics. Otherwise ⁇ if the different sensor signals would be only random and the measured signal difference could not for to provide a reliable distinction between an object and a person on the vehicle seat.
• a secure person-object distinction in particular a child-seat differentiation, can be given, for example, if the first or several first weight sensors output less than 50% of the signal amplitude of at least one of the plurality of second weight sensors with the same weight load: this signal difference in general far more than the usual measuring tolerances in such a sensor device.
• this signal difference in general far more than the usual measuring tolerances in such a sensor device.
• a signal height that is only 30% lower than the signal level of at least one of the plurality of second weight sensors often already suffices by 30% or, in the case of very accurate measuring arrangements, even by only 5%.
• the first sensor or the first weight ⁇ weight sensors no weight load experienced by such an object. Then, the distinction of the signals of the loaded second weight sensors from the signals of one or more unloaded first weight sensors is particularly simple.
• the object is further achieved by a method according to claim 6.
• the object is further achieved by a method according to claim 6 for distinguishing whether a person is on the seat of a vehicle seat or an object with at least one largely planar bearing surface which is arranged over a large part of the seat including a central region, the method comprising a device having a seat mat with weight sensors distributed on the seat surface of the vehicle seat and an evaluation unit which transmits the signals the Weightsso ⁇ ren fed are used. Furthermore, in the OF INVENTION ⁇ to the invention process and the following process steps occur:
• the comparison of the signals of the weight sensors can be carried out, for example, as a comparison of a first weight sensor with an average value of the signals of the second weight sensors. In the case of a plurality of first weight sensors, an average value of the signals of the first weight sensors may instead be used for the comparison. However, the signals of the first and second weight sensors can also be compared with each other individually, possibly also combined with a comparison of mean values. The recognition of the object takes place on the basis of the result from this comparison or these comparisons of the signals of the weight sensors.
• a further advantageous embodiments of the erfindungsge ⁇ MAESSEN method are given in the claims 7 to 9.
• this safe and simple method is particularly advantageous for use in occupant protection systems in which the activation of an occupant restraint device always occurs when an object with a largely flat contact surface is detected should be suppressed, preferably when a child seat is detected as an object. It is conceivable, however, that other recognized objects to the De ⁇ activation should lead an occupant restraint means:
• the method is also advantageous to be ⁇ sets are also having to detect large packages or the like, a largely flat bearing surface.
• Figure 1 shows a device according to the invention with a
• Figure 2 shows the motor vehicle seat of Figure in cross section with a child seat on its seat
• Figure 3 is a vehicle seat as in Figure, but with a
• Figure 4 shows the schematic course of weight-dependent characteristics of weight sensors of a device according to the invention
• FIG. 5 shows a method sequence according to the invention.
• Figure 1 shows an embodiment of a erfindungsge ⁇ Permitted device with motor vehicle seat 1 with a seat back 11 and a seat 2 in plan view; on a seat mat 3 is arranged, the weight-sensitive sensors S R , S M has, at which each a sensor signal from an evaluation ⁇ unit 7 can be tapped, which provides information about the forces acting on the sensors S R and S M weight forces.
• a bordered area provided with the reference symbol M represents a surface-centered area of the seat surface 2, in which area-centered weight sensors S M are arranged.
• the evaluation unit 7 is verbun ⁇ with a trip unit 8, which can cause the triggering of an occupant protection means 9 in ⁇ example, a front airbag when the Signa- Ie of (not shown) impact sensors, for example, acceleration or pressure sensors, are characteristic of an impact accident.
• a dashed square area 10 on the seat 2 represents the largely flat Auflageflä ⁇ che of a child seat 4.
• the largely flat support surface does not necessarily occupy the entire closed surface 10.
• the flat surface 10 may be interrupted by a recess.
• FIG 2 shows the motor vehicle seat 1 of Figure 1 in cross section along the cross-sectional line AA.
• the child seat 4 is arranged, in which a child is located.
• the weight of the child seat 4 with the sit on the child ⁇ 5 is distributed evenly over the largest part of the seat mat 3; also on the center area M of the seat.
• the weight sensors located therein S M and the edge is arranged on the seat sensors S R lie away each ⁇ a measurable by the evaluation unit 7 ge ⁇ weight-dependent signal.
• the sensors S M supply in the central region M, which are acted upon with a comparatively same weight as the peripheral simultaneouslyssenso ren ⁇ S R, a relatively lower signal than the edge-side ⁇ weight sensors S R.
• FIG. 3 shows a person 6 on the vehicle seat.
• the buttocks of the person 6 biases the central portion M of the seat 2 of the vehicle seat 1 being significantly stronger than the surrounding peripheral parts of the seating surface 2. It is applied there comparatively ⁇ as more weight on the seat 2 as au ⁇ ßerrenz this central area M, so in that the central region M of the seat surface 2 of the vehicle seat 1 curves concavely in the direction of the vehicle floor.
• Another part of the weight of the person 6 usually takes on the bottom of Fahr ⁇ vehicle interior, since there usually are the legs of the person;
• the seat back 11 also takes on weight, since the person 6 is usually based on the Wegleh ⁇ ne 11.
• the armrests, the steering wheel, etc. take on a part of the weight of the vehicle occupant, as this there preferably puts off his arms or holds on, etc.
• FIG. 4 shows a respective characteristic of a peripheral Sen ⁇ sorelements S R and a center sensor element S M reference to a schematic representation.
• the abscissa is the Sensor signal sig applied.
• the ordinate shows the Ge ⁇ weight force G acting on the sensor cell.
• the solid line s R represents the characteristic for a peripheral weight sensor S R : only after reaching a minimum weight PS R , for example, depends on the size of the sensor cell of the weight sensor S R , the curve S R continuously increases to higher weight forces E out and almost linear until the sensor signal tapers to a constant value. Thereafter, even with a further increase in the weight G, no additional sensor signal can be generated .
• the dashed line s M shows schematically the charac- diagram characteristic of the center sensor element S R: to a ⁇ setting a minimum signal PS M must in this sensor element more weight force G applied as a term in which randsei ⁇ sensor element S R. Thereafter, this characteristic increases continuously with increasing weight G until it tapers to a constant value. Even with a further increase in the weight G, the sensor signal sig of the central weight sensor S M does not exceed this value. This maximum signal value of the central weight sensor S M depending ⁇ but comparatively lower than that of the marginal weight-sensor S R.
• a different characteristic curve of weight sensors can be effected in different ways and depends on the construction of the weight sensor .
• a typical weight sensor which is also often used, for example, in an article according to DE 214 200 U1 mentioned in the introduction, consists of two conductive surfaces which are laminated on two opposite films. The two films are held apart by spacers, so-called spacers. Under force, the two conductive surfaces approach until they finally touch each other. Takes the force continues to increase, so does the touch ⁇ enlarged area. By contacting the two conductive surfaces, the resistance of the contact surface is determined.
• the resistance of a thus configured weight sensor is thus dependent on the weight force acting on the at ⁇ the associated films.
• a change in the characteristic curve of a weight sensor can be effected for example by ei ⁇ ne larger or smaller conductive surface o- also by a change in the distance of the films to each other in retirement, which is more complex. This is explained in more detail below.
• the almost linear range of a sensor characteristic is the preferred working range for a weight sensor.
• the range of weight can in the at least one sensor signal continu just change ⁇ ously still so strong depending on the weight that it used for reliable detection of a weight who can ⁇ is, usually maximum by the Vorrich- processing to be detected, meaningful weight range.
• this weight range can also be selected to be smaller. Should a larger be required recapitulative weight range, it must usually the sensor geometry to be adjusted accordingly, so at ⁇ play as increases the sensor cells or reduced ⁇ to, as has been described above.
• FIG 5 shows an exemplary embodiment of a method according to the invention ⁇ SLI.
• the evaluation unit 7 detects in a method step 400 the signals of the space-centered first weight sensors S M.
• a weight value GWM is derived from these sensor signals which is characteristic of the weight loading on the area-centered area M of the seat surface 2. For example, a weighting, if necessary additionally weighted, can be derived.
• Mean value of the sensor signals of the area-weight sensors S M are formed.
• the value obtained is compared in GWM ei ⁇ nem further method step 800 with a threshold value TH.
• a second process step II the same time or staggered in time for the first process stage I saufin ⁇ det, 400 ', the sensor signals of the second weight sensors S R outside the central loading are determined Reich M of the seat 2 in a process step and the sensor signals of the first weight sensors, if this has not already happened in method step 400.
• a value GWM derived from the signals of the first weight sensors which is characteristic of the weight load on the center of the area.
• a corresponding value GWR will be off the signals of the second weight sensors S R , which is characteristic for the weight load outside the central region M of the seat 2.
• a next method step 800 the difference between the two values GWM and GWR is compared with a threshold value TH 1 .
• This difference exceeds the threshold value TH 1, wherein ⁇ game example by 5%, 30%, 50% or even more, so this is an indication that a person located on the seat 6 are 2 and could no object. If the value GWM also exceeds the threshold value TH, this is a further indication of a person 6 on the vehicle seat.
• these two instructions are logically linked to one another and as a result, in a further method step 1100, the presence of a person 6 on the Wegflä ⁇ che 2 detected.
• step 1000 these two information of the semi ⁇ be logically combined and the presence of egg nes child seat 4 on the seat surface 2 in a further method step 1200 detected.
• the information as to whether a person 6 or a child seat 4 is present on the seat surface 2 of the motor vehicle seat is fed to the evaluation unit 7 for evaluation by a stored special algorithm. This is illustrated in Fi gure 5 ⁇ by the step 14oo. Al ⁇ rithm the evaluation also be crash signals supplied by suitable crash sensors, which can be evaluated by the algorithm. Based on this assessment, the information is in the evaluation of whether a clergymansi ⁇ situation is present or not.
• the algorithm therefore makes the decision in a further method step 1500 as to whether the ignition, for example of an airbag, is required or not. If no ignition of an air bag due to the crash signals required so decides, the evaluation unit 17 in a further method step 1600, ⁇ that no ignition of the airbag occurs.
• the evaluation unit 7 decides, in a further procedural ⁇ rens intimid 1700 that an air bag should be triggered.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Seats For Vehicles (AREA)
• Air Bags (AREA)

Applications Claiming Priority (2)

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• 2005
  • 2005-03-30 DE DE102005014526A patent/DE102005014526A1/de not_active Ceased
• 2006
  • 2006-03-28 US US11/910,277 patent/US7817056B2/en not_active Expired - Fee Related
  • 2006-03-28 WO PCT/EP2006/061103 patent/WO2006103237A1/de not_active Application Discontinuation
  • 2006-03-28 EP EP06725365A patent/EP1863684A1/de not_active Withdrawn
  • 2006-03-28 JP JP2008503503A patent/JP2008535719A/ja active Pending

Non-Patent Citations (1)

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