DE102016219517B4 - Motor vehicle and method for determining an occupant information - Google Patents

Abstract

Motor vehicle (2), comprising at least one seat (3) for a person (18) in an interior (1), at least one on the seat (3) directed radar sensor (8, 9) in the interior (1) and one the radar data characterized in that in a seat cover (5) of the seat (3) a radar reflective material is integrated in the radar sensor (8, 9) for determining an occupant on the seat (3) person (18) descriptive occupant information evaluating control device (15) , wherein the control device (15) for determining the occupant information is formed at least partially as a function of the radar visibility of the seat cover (5).

Description

The invention relates to a motor vehicle, comprising at least one seat for a person in an interior space, at least one radar sensor directed to the seat in the interior and a control device evaluating the radar data of the radar sensor for determining a passenger information on the seat descriptive occupant information. In addition, the invention relates to a method for determining an occupant information on a seat of such a motor vehicle descriptive.

Modern motor vehicles have a variety of driver assistance systems and safety systems that can assist the driver, especially in critical traffic situations, where various types of sensors can be used. For interior monitoring, optical sensors, for example camera systems, are usually used for fatigue detection, gesture control or driver monitoring.

An important safety system for motor vehicles are airbag devices which include an airbag which is inflated in the event of an accident or collision and thus should avoid injury to the occupants. The triggering of the airbag thus plays an important role in reducing the severity of the accident. However, sometimes airbag itself also presents problems, in particular if there is an incorrect seating position of the occupant relative to the airbag. While at the correct sitting position possibly lighter injuries can occur, with a wrong seat position also heavier injuries are conceivable in principle.

An important factor for the risk of injury by an airbag is the relative distance between the occupant and the airbag. This relative distance, in turn, depends on the size of the person, who in turn depends on the age (child or adult), gender and also the required sitting position (depending on the driving situation). As unfavorable case for a bad sitting position, a small female person, the so-called 5% woman, is usually accepted in studies of airbag safety. Another group of people to be protected is that of 4- to 8-year-old children. Children often experience unusual or restless sitting positions.

In order to determine whether a suitable sitting position of the occupant is present on the seat, optical sensors are rather unsuitable, since they depend on the one hand on the ambient brightness, but on the other hand also visible in the motor vehicle must be installed, which is usually undesirable. If the optical sensors, for example a camera, are aimed precisely at a surveillance area corresponding to their purpose, it is often impossible to make a general statement about the seating position. For example, in driver monitoring, a camera is aimed precisely at the driver's face to monitor head movements or facial eye activity.

WO 99/54173 A1 discloses an occupant detection system for controlling the activation of an airbag inflator. The detection system includes a transceiver subsystem that emits a beam of wave energy through an area normally occupied by an occupant in a normal sitting position, but not by an occupant out of normal sitting position or a child seat , The receiver is installed to receive the beam of wave energy in the seat. An occupant in the normal sitting position is detected by the interaction with the beam of wave energy. In addition, a distance / proximity measurement subsystem is provided to determine if the occupant is possibly too close to the airbag. The airbag is activated only when a person is in the correct sitting position and at an appropriate distance. The transceiver subsystem can use radar signals. The problem here is that from the information of the transmitter / receiver subsystem no more accurate information about the occupant can be derived after this works as a simple switch. The same applies to the distance sensor, which only provides information about the distance. A more accurate assessment of the seated posture of the occupant on the seat is not possible.

In DE 196 37 108 A1 An occupant protection system for motor vehicles and a method for continuously monitoring the seating position of the occupant are described. In this case, by one or more transmitting and receiving devices of a distance measuring device reflected rays emitted, which are reflected at least one reference point of a safety belt. By evaluating the results of the distance measurements, a warning to the occupant can be output if the safety belt is less than a safety belt seated to an airbag and / or the airbag is not inflated or only slowed down in the event of an accident.

DE 103 34 063 A1 describes a vehicle restraint system with a dynamic classification of a vehicle occupant. The inflation rate of an airbag is determined based on the mass, position and physical characteristics of the occupant. In this case, for example, a mass sensor for determining the mass and a Radar sensor are used to determine the position of the occupant and the distance of the occupant to the airbag. Other physical characteristics include distance from the occupant's head to his or her shoulders and the distance from the occupant's head to a seat. The radar beams are reflected at the occupant. Depending on the recorded results, an airbag will not inflate or at reduced speed in the event of an accident.

In DE 44 92 128 C2 there is described a vehicle occupant protection system in which the position of an occupant is determined by waves emitted by a transmitter which are reflected at the occupant. Using pattern recognition means, the waves reflected by the occupant are processed to distinguish between the occupant and his extremities due to their relative size, position or shape. With the aid of the pattern recognition it can be determined from which body part of the occupant the position to the airbag has been determined, whereby, for example, a triggering of the airbag can be prevented if the head of the occupant is too close to a cover of the airbag.

The invention is therefore based on the object to obtain a simple way to obtain more accurate information about an occupant located on a seat of a motor vehicle.

To solve this problem is inventively provided in a motor vehicle of the type mentioned that a radar reflective material, in particular metal, is integrated in a seat cover of the seat, wherein the control device for determining the occupant information is at least partially formed depending on the radar visibility of the seat cover.

The invention is therefore based on the idea to create a contrast in the radar image of the radar sensor in a simple manner by the seat cover of the seat, thus the surface, is radar highly reflective compared to an occupant by introducing or using a corresponding material is, in particular a metal. Radar-reflecting therefore means in particular that there is a reflectivity for radar beams which is higher than the reflectivity for radar beams by a person, preferably at least ten times as high. In the radar data of the radar sensor, it is now possible to determine whether in the area from which the radar radiation is reflected, the driver's seat is present, thus the seat cover strongly reflected (high signal), or if there is a person who reflects much worse.

In this case, the at least one radar sensor is preferably concealed behind a material which can be penetrated by radar radiation, for example a cover element and / or cladding element. Here are preferably small-sized radar sensors in semiconductor technology, in particular CMOS technology, used, for example, in sizes of about 3 cm x 3 cm x 1 cm or less can be realized and thus in functional elements, such as a steering wheel, can be installed. The radar sensor is thereby positioned so that it detects the seat, that is, for example, shows its main beam direction in the direction of the seat. If a person takes seat on the seat, certain areas of the seat and thus of the seat cover are concealed, so that the reflection patterns in the radar data change. In other words, the radar sensor detects this change in the reflection properties.

Since the human body is absorbing for high frequency radar radiation, degradation of the radar beam propagation paths between the radar sensor and the reflective seat cover will detect a change in performance (degradation). If certain areas of the seat cover are not covered, no performance degradation is detected and the areas can be marked as unoccupied. The distribution of the occupied and unoccupied areas then results in a more accurate statement about the current posture of the occupant relative to the radar sensor. Thus, it allows the special design of the seat to gain significantly improved information about the person on the seat, especially his posture or posture.

Thus, it is provided in a particularly preferred embodiment of the present invention that the control device for determining body posture information, which describes the posture of the person, is designed as occupant information. Such body posture information may be evaluated extremely expediently with regard to the actuation of an airbag device, but may also be useful for other vehicle systems, for example a system for driver monitoring, to assist in the correct seat adjustment and the like.

In this context, it is also particularly preferred if the control device for segmenting a radar image formed by the spatially resolved radar data in the seat cover and the person associated areas is formed as a function of the radar reflectivity described by the radar data. As already discussed, due to the signal degradation occurring due to the presence of the person, segmentation into occupied (little Reflection) and unoccupied (much reflection from the seat cover) areas instead. There are certain reflection patterns in a radar image, which change depending on the posture of the occupant.

In an extremely expedient development of the invention, provision may additionally be made for the control device to determine occupant information describing the position and / or the movement of at least one hand and / or head of the person, in particular as part of the posture information and / or relative position of the head is formed relative to a headrest of the seat and / or as Kopforientierung, by evaluation of Doppler shifts in the radar data. By movements of the occupant arises in the radar data Doppler shift, which is suitable to detect corresponding movements of the hands and / or the head, so that thus the posture can be evaluated with respect to the hands and the head and determined as occupant information. In particular with regard to safety in the motor vehicle, a position of the head relative to a headrest of the seat can also be considered, whereby in the case of an unfavorable position of the head relative to the headrest, for example, corresponding information can be output to the occupant and / or a seat adjustment device, which also The headrest can adjust, can be controlled properly. The knowledge of the head orientation is also useful when the driver's line of sight is to be derived, which also constitutes useful information for some driver assistance systems or vehicle systems, which can be used, for example, to check the plausibility of sighting information determined with other sensors.

Preferably, the control device for controlling an airbag device associated with the seat can be designed as a function of the occupant information. Essential is an occupant information, in particular a body posture information, in particular with regard to the actuation of airbag devices, in order to be able to reduce injury risks for the occupant by the airbag and, if appropriate, to suppress an actuation if there is a risk for the person. In particular, therefore, triggering criteria can be defined that evaluate the occupant information, in particular body posture information, and thus evaluate the risk of airbag deployment.

Expediently, the control device for evaluating the radar data for determining a distance of the person from an airbag of the airbag device can be embodied as occupant information. In particular, as additional information, the distance of the person from the airbag can therefore be determined and evaluated, since radar sensors are particularly suitable for distance measurements. Specifically, it can be provided that the control device is further designed to check whether the distance is within a permitted reference interval interval, and at spaced outside the reference distance interval to output a hint information regarding the distance and / or driving a seat adjustment device for producing a within the reference distance interval lying distance is formed. In other words, the distance can be monitored and trigger a feedback that indicates an unsafe seating position, in particular with too low a distance to the airbag or confirms a safe seating position with a distance in the reference distance interval. Such monitoring functionality may also be combined with automatic seat adjustment by a seat adjuster to further assist the occupant. In this case, it is expedient to carry out a temporal course analysis in such a distance monitoring function in order to not acknowledge short-term changes in the seating position, for example a recline in the seat or the like, with a warning and / or seat adjustment. It should be noted that, of course, when evaluating an airbag deployment, the evaluation of the triggering criteria always relates to the current state of the occupant.

On the basis of the radar data containing the more detailed information in the embodiment according to the invention, further occupant information can also be derived. Thus it can be provided that the control device is designed to determine a seat occupancy information and / or a condition of the person in or outside the seat and / or a body size as occupant information. In addition to the seat occupancy itself, which is useful information for various vehicle systems, a number of cases can be distinguished with regard to the condition of the person in or out of the seat, for example an in-position with normally seated occupants, an out position at partial, but not too strong, out of the seat arranged position of the occupant and / or a critical-out position in a strong deviation from the normal seating position or even a complete departure from the seat. In addition, the precise information that arises in particular during segmentation also allow conclusions to be drawn regarding the body size of the occupant, which can also be taken into account for vehicle systems, if appropriate also in the case of airbag deployment.

In a particularly advantageous embodiment of the present invention can be provided that two seat-directed radar sensors are used, one of which is the seat frontally and one detects the seat from above and wherein the controller evaluates the radar data of both radar sensors together. Thus, it can be provided to detect the seat and thus also a person located on the seat from two directions, in particular mutually perpendicular, in order to obtain a complete radar image of the occupant condition on the seat, so that very accurate information regarding the posture, the condition the seat and the like can be derived as occupant information. In this case, the radar data of the at least two radar sensors are thus fused in order to obtain an extremely accurate image of the occupancy, posture of the occupant, etc.

Specifically, it can be provided here that at least one of the at least one radar sensor is concealed in a steering wheel and / or a cladding element of the motor vehicle and / or at least one of the at least one radar sensor is concealed in a ceiling cladding of the interior. In particular, when using small-scale based on semiconductor technology, in particular CMOS technology, radar sensors such covert installation in functional components and / or in cladding elements of the motor vehicle can be easily implemented without too much space is required or affects the design of the interior of the motor vehicle becomes.

A concrete realization of the present invention provides that, in particular in the case of a fabric-comprising seat cover, the radar-reflecting material is designed as metal filaments. In particular, therefore, metal threads can be integrated into a fabric of the seat cover to ensure the increased radar reflectivity of the seat cover and thus the seat surface. For example, metal-containing fibers or threads may be used to form the fabric of the seat cover and / or metal threads may form part of the fabric.

In order to detect a radar image which can be evaluated in several directions, it is particularly expedient in the context of the invention if the radar sensor has an antenna arrangement designed for angle measurement in two mutually perpendicular planes. By way of example, the antenna arrangement can have individual antenna elements which are arranged in the form of a matrix and follow one another in two mutually perpendicular directions. Thus, for example, an angular resolution is possible both in the elevation and in the azimuth, so that, for example, the segmentation can result in a two-dimensional image of seat cover areas and person areas. If distance information is derived, even a three-dimensional image of the seat with the person is possible.

It should be noted that the radar sensors used in the invention of course already include the transmitter and the receiver in a single unit, since it is about the measurement of the reflected radar radiation in order to exploit the increased radar reflectivity of the seat cover can.

It should also be noted that the motor vehicle can of course have multiple seats, each of the seats at least one radar sensor can be assigned to its detection in order to determine the occupant information for several, especially all, seats of the motor vehicle, in particular so also the posture of the respective occupant. In any case, it is expedient to be able to determine occupant information for each seat to which an airbag is assigned.

As already mentioned, in the context of the present invention, the availability of modern, small-sized and high-quality radar data-providing radar sensors based on semiconductor technology, in particular CMOS technology, can be utilized.

The realization of semiconductor-based radar components has long proved difficult, as expensive specialty semiconductors, particularly GaAs, have been required. Smaller radar sensors have been proposed, whose entire radar frontend is realized on a single chip in SiGe technology before solutions in CMOS technology became known. Such solutions are the result of extending CMOS technology to high frequency applications, often referred to as RF CMOS. Such a CMOS radar chip is realized extremely compact and does not use expensive special semiconductors, thus offers significant advantages over other semiconductor technologies, especially in the production. An exemplary implementation of a 77 GHz radar transceiver as a CMOS chip is described in the article by Jri Lee et al., "A Fully Integrated 77 GHz FMCW Radar Transceiver in 65 nm CMOS Technology", IEEE Journal of Solid State Circuits 45 (2010), pp. 2746-2755.

After it has also been proposed to realize the chip and the antenna in a common package, a very low cost small radar sensor is possible, which can meet the space requirements significantly better and due to the short signal paths also has a very low signal-to-noise ratio and for high frequencies and larger, variable frequency bandwidths is suitable. Therefore, such small-sized radar sensors can also be used for short-range applications, for example in the range of 30 cm to 10 m.

It has also been proposed to provide such a CMOS transceiver chip and / or a package with CMOS transceiver chip and antenna on a common circuit board with a digital signal processing processor (DSP processor) or the functions of the signal processing processor in the CMOS Integrate transceiver chip. Similar integration is possible for control functions.

Consequently, it is also particularly advantageous in the context of the present invention for the radar sensor to comprise a semiconductor chip implementing a radar transceiver. Expediently, a digital signal processing component of the radar sensor and / or a control unit of the radar sensor can be realized by the semiconductor chip and / or an antenna arrangement of the radar sensor and the semiconductor chip can be realized as a package. In this way, an extremely small-scale radar sensor is created with an excellent quality of radar data, which provides high-quality information, especially in the vicinity. The radar sensor may expediently be operated with a high frequency bandwidth, in particular of 4 GHz, and / or in a frequency range of 77 to 81 GHz.

In addition to the motor vehicle, the invention also relates to a method for determining occupant information on a seat of a motor vehicle according to the invention, wherein the radar data of the radar sensor are evaluated by the control device to determine the occupant information and determines the occupant information at least partially as a function of the radar visibility of the seat cover becomes. All statements relating to the motor vehicle according to the invention can be analogously transferred to the inventive method, with which therefore the already mentioned advantages can also be obtained.

• 1 eine Prinzipskizze eines Ausschnitts eines erfindungsgemäßen Kraftfahrzeugs,
• 2 eine Detailansicht eines Sitzbezugs eines Sitzes des Kraftfahrzeugs,
• 3 ein Radarbild eines unbelegten Sitzes,
• 4 ein Radarbild eines belegten Sitzes, und
• 5 ein Radarbild eines belegten Sitzes bei Veränderung der Körperhaltung.

Further advantages and details of the present invention will become apparent from the embodiments described below and with reference to the drawings. Showing:

• 1 a schematic diagram of a section of a motor vehicle according to the invention,
• 2 a detailed view of a seat cover of a seat of the motor vehicle,
• 3 a radar image of a blank seat,
• 4 a radar image of a seat occupied, and
• 5 a radar image of a seat occupied when changing the posture.

1 shows a section of the interior 1 a motor vehicle according to the invention 2 in the area of the driver's seat 3 , The driver's seat 3 on the present a driver 4 shown as a person or occupant, has a seat cover comprising a fabric 5 on, in the present radar reflective material is integrated, which reflects radar much better than a person like the driver 4 ,

As 2 shows are in the tissue 6 the seat cover 5 metal filaments 7 incorporated. For example, the metal threads 7 in the textile structure of the seat cover 5 be woven. In this case, the distances of the individual metal threads 7 depending on the wavelength of the radar radiation used so chosen that the highest possible radar reflectivity in the frequency range used, from 77 to 81 GHz, is given.

In the interior 1 of the motor vehicle 2 are now concealed two the driver's seat detecting radar sensors 8th . 9 installed. The respective coverage areas 10 are indicated by dashed lines. Both radar sensors 8th . 9 are implemented in CMOS technology kleinbauend and have a semiconductor chip, here CMOS chip, on, in addition to the radar transceiver and a digital signal processing component and a control unit of each radar sensor 8th . 9 will be realized. The antenna arrangement of the respective radar sensor 8th . 9 is realized as a package with the respective semiconductor chip. In this case, the antenna arrangement additionally has antenna elements which follow each other in a matrix-like manner in two mutually perpendicular directions, so that an angle detection in two mutually perpendicular planes is made possible.

Specifically, the radar sensor is 8th who ultimately supervised the seat 3 and the driver 4 allows in a ceiling cladding 11 concealed installed, the radar sensor 9 in a steering wheel 12 , For other seats 3 For example, a passenger seat, a corresponding radar sensor 9 also behind another cladding element of the motor vehicle 2 be provided.

It should be noted that centrally in the steering wheel 12 also the airbag of an here only indicated airbag device 13 is located, which is not shown for clarity.

Radar data of radar sensors 8th . 9 be through a control unit 14 of the motor vehicle 2 as part of a control device 15 evaluated to determine occupant information from the radar data, in this case a body posture information, a distance from the airbag in the steering wheel 12 , a position of the driver's head 4 as a person relative to a headrest 16 of the seat 3 , a condition of the person in the seat 3 (In position, Out position or Critical Out position), a seat occupancy information, a height and a head orientation. At least partially, this is the different radar reflectivity of the seat cover 5 and the driver 4 or the person in general, in particular with respect to the body posture information. Positions of moving parts of the driver 4 as a person, especially the hands and the head, can be determined by evaluation of Doppler shifts, possibly assisting; Distance measurements with radar sensors 8th . 9 are known in principle.

To the posture of an occupant, such as the driver 4 to be able to evaluate, is the respective radar image of the radar sensors 8th . 9 segmented based on the radar reflectivities, in this case in areas that the seat cover 5 and areas that belong to the person, here the driver 4 , are to be assigned. Due to the strong radar reflection through the seat cover 5 and the high absorption of radar radiation in the range of 77 to 81 GHz by persons, this is possible in a simple evaluation. This is exemplified by the 3 to 5 , the radar images of the radar sensor 9 can correspond. In 3 There is no person in the driver's seat 3 so that an overall, highly reflective image of the seat cover 5 as the only area 17 arises. 4 schematically shows the radar image when occupying the seat 3 with one person 18 For example, the driver 4 , in a normal sitting position. A part of the seat cover is visible 8th by the person 18 covered, giving strong reflections in the field 19 only the person 18 appear bordering. 5 shows a change in the posture of the person 18 that leads to other areas 20 with strong reflection emerge as other parts of the seat cover 5 be visible in the radar image.

Radar data, in particular radar images, radar sensors 8th and 9 In addition, they are jointly evaluated in order to obtain as accurate a picture as possible of the person's posture by fusion of the radar data 18 , specifically the driver 4 , to obtain.

Received occupant information is presently provided by the controller 15 evaluated to trigger an airbag of the airbag device 13 be controlled in such a way that the risk of injury to the person 18 kept as low as possible. Furthermore, but also outside a triggering case by the control device 15 the sitting position and posture of the driver 4 or the person 18 constantly monitored to determine unfavorable postures / sitting positions and, where appropriate, can issue appropriate instructions and / or to be able to control a seat adjustment device not shown here. Also the position of the head relative to the headrest 16 can thus be constantly monitored and assessed, possibly also an automatic adjustment of the position of the headrest 16 can be done. Of course, the occupant information determined with the aid of the present invention can also be taken into account when controlling other vehicle systems.

Claims (10)

Motor vehicle (2), comprising at least one seat (3) for a person (18) in an interior (1), at least one on the seat (3) directed radar sensor (8, 9) in the interior (1) and one the radar data characterized in that in a seat cover (5) of the seat (3) a radar reflective material is integrated in the radar sensor (8, 9) for determining an occupant on the seat (3) person (18) descriptive occupant information evaluating control device (15) , wherein the control device (15) for determining the occupant information is formed at least partially as a function of the radar visibility of the seat cover (5). Motor vehicle (2) according to Claim 1 , characterized in that the control device (15) for determining body posture information, which describes the posture of the person (18), is designed as occupant information. Motor vehicle (2) according to Claim 1 or 2 , characterized in that the control device (15) for segmenting a radar image formed by the spatially resolved radar data in the seat cover (5) and the person (18) associated areas (17, 19, 20) formed in dependence of the radar reflectivity described by the radar data is. Motor vehicle (2) according to one of the preceding claims, characterized in that the control device (15) for determining an occupant information describing the position and / or movement of at least one hand and / or head of the person (18) by evaluating Doppler shifts in the Radar data is formed. Motor vehicle (2) according to one of the preceding claims, characterized in that the control device (15) for controlling a seat (3) associated with the airbag device (13) is formed in dependence on the occupant information. Motor vehicle (2) according to Claim 5 , characterized in that the control device (15) for evaluating the radar data for determining a Distance of the person (18) of an airbag of the airbag device (13) is designed as occupant information. Motor vehicle (2) according to one of the preceding claims, characterized in that the control device (15) for determining a seat occupancy information and / or a condition of the person (18) in or outside of the seat (3) and / or a body size is designed as occupant information , Motor vehicle (2) according to one of the preceding claims, characterized in that, in particular in a fabric (6) comprehensive seat cover (5), the radar reflecting material is formed as metal filaments (7). Motor vehicle (2) according to one of the preceding claims, characterized in that two radar sensors (8, 9) directed towards the seat (3) are used, one of which detects the seat (3) from the front and one the seat (3) from above and wherein the control device (15) jointly evaluates the radar data of both radar sensors (8, 9), and / or obscures at least one of the at least one radar sensor (8, 9) in a steering wheel (12) and / or a cladding element of the motor vehicle (2) is installed and / or at least one of the at least one radar sensor (8, 9) in a ceiling lining (11) of the interior (1) is installed concealed. Method for determining occupant information describing a person (18) located on a seat (3) of a motor vehicle (2) according to one of the preceding claims, wherein the radar data of the radar sensor (8, 9) is evaluated by the control device (15) to determine occupant information be determined and the occupant information at least partially depending on the radar visibility of the seat cover (5).

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