Abstract:
A parking assistance system for a motor vehicle includes a monitoring unit for detecting an object in the vicinity of the vehicle and a light system connected to the monitoring unit and configured to emit light into the area surrounding the motor vehicle. The monitoring unit is configured to sense the bearing of an object and to control the distribution of the light emitted from the light system as a function of the sensed bearing.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to German Patent Application No. 102016004259.1, filed Apr. 8, 2016, which is incorporated herein by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The present disclosure pertains to a parking assistance system and a method of assisting the parking of a motor vehicle. 
       BACKGROUND 
       [0003]    Parking assistance systems may be incorporated into a motor vehicle with a motoring unit for sensing an object in the vicinity of the motor vehicle, e.g. on the basis of radar signals, and a signal emitter controlled as a function of the results of a sensed object are generally known. The signal emitter can be a display on which the position of the object relative to the motor vehicle and its distance therefrom is visualized, in addition an acoustic signal emitter may be provided. From this information, the driver can estimate the distance from the object, irrespective of the direction in which he or she is looking. 
         [0004]    DE 10 2009 058 034 A1 describes a parking assistance system with a monitoring unit which can also continue to be operated after completion of the parking in order to monitor, on the parked motor vehicle, the approach of other motor vehicles to the parked motor vehicle, and a lamp, which is controlled by the monitoring system to warn the driver of such another motor vehicle by way of a light signal of a critical approach. 
         [0005]    The beeping sounds used as acoustic warning signals by most conventional parking assistance systems are considered as unpleasant or annoying by many users, particularly if the sound level is poorly adapted to the noise level of the surroundings. If a driver who feels annoyed by the signals of a conventional parking assistance system turns down its sound level, there is the risk that when the motor vehicle is subsequently driven by another driver who is not aware of the reduced sound level, this driver may not hear the signals and thus presumes that there is no obstacle in the way. 
         [0006]    A further problem is that the acoustic signals used usually have a high frequency in order to be easily perceived by a driver with normal hearing against a background of engine sounds at lower frequencies, but drivers with a degree of hearing loss may find such signal difficult to discern. 
       SUMMARY 
       [0007]    The present disclosure provides a parking assistance system for a motor vehicle or a method of assisting the parking of a motor vehicle which achieves a high degree of reliability without being dependent on acoustic signals. In one aspect, a parking assistance system for a motor vehicle with a monitoring unit for detecting an object in the vicinity of the vehicle and a lighting system which in order to emit light into the area surrounding the motor vehicle is connected to the monitoring unit. The monitoring unit is configured to sense the bearing of an object and to control the distribution of the light emitted from the lighting system as a function of the sensed bearing. As it is to be assumed that as the driver of the motor vehicle observes his/her surroundings when parking, he/she will not fail to notice the change in light distribution and will recognise that there is an object in the vicinity of the vehicle with which a collision is possible. 
         [0008]    Such a control system could, for example, include sensing a bearing angle, which shows the direction in which the object lies in relation to the motor vehicle in a vehicle-based coordinate system and directing a directable light source onto the detected object and thus increasing its conspicuousness to the driver. However, such a procedure has the drawback that low-lying objects in the vicinity of the motor vehicle may be hidden from the driver&#39;s view by the bodywork and cannot therefore be seen when they are selectively illuminated. Problems can also arise if the object has already been passed and is no longer in the driver&#39;s line of vision. For example, when parking in a multi-storied car park or parking garage, it is possible to scrape a column adjoining a parking space with a rear section of the vehicle body while the driver is looking forwards in order not to hit a wall delimiting the parking space. It is therefore expedient to control the light distribution in a spatial area in a driving direction in front of the driver, irrespective of whether the detected object is located in this spatial area or is already behind the driver. 
         [0009]    Sensing the object bearing may be as simple as determining which side of the motor vehicle a detected object is located. The result of detecting the object and, if applicable, the decision, can be signalled to the driver in a simple and reliable manner if the control unit is configured to produce a first light distribution if no object is detected, a second light distribution on detecting of an object on the left-hand side of the motor vehicle and a third light distribution on detecting of an object on the right-hand side of the motor vehicle. 
         [0010]    In order to produce these different light distributions a pair of lights on different side of a middle plane of the motor vehicle is sufficient. The monitoring unit is then configured to operate both lights in an identical first operating state in order to produce the first light distribution, and to produce the second and third light distribution to operate in each case one light in the first operating condition and the other light in a second operating condition differing from the first operating condition. 
         [0011]    Conventionally, as lights for the parking assistance system according to the present disclosure lamps which are available in pairs on any motor vehicle authorized for road traffic, such as indicators or front headlights, can be used. The upgrading of a conventional parking assistance system providing an acoustic signal to form a system according to the present disclosure therefore requires no additional components and is possible with minimal cost outlay. 
         [0012]    Expediently the monitoring unit is not only configured to take bearings, but also for sensing the distance of the object and to control at least one property of the light of the lamp in the second operating condition as a function of the sensed distance. The driver therefore receives feedback not only about the presence of an object but also about its distance and can therefore reliably assess the danger posed by the object. 
         [0013]    The controlled property of the light source can be selected from among the intensity, color, spatial distribution or time distribution of the light. Control of the intensity or time distribution is possible in the case of practically all lights commonly used in the motor vehicle sector. In the case of conventional front headlights control of the spatial distribution can be achieved by switching between full or high beams and dipped or low beam. In the case of modern adaptive frontlight system (AFS) headlights the light level of which follows the angle the steering wheel is turned when travelling on open roads, the change in the spatial distribution can be obtained through turning that is independent of the angle of turning of the steering wheel. Matrix headlights with several elemental light sources that can be controlled independently of each other offer much further-reaching possibilities of varying the spatial distribution. 
         [0014]    Particularly with matrix headlights, but also in the case of other type of headlights, control of the spatial distribution can include an opening angle between two light-dark boundaries of the emitted light being varied. By way of the dimensions or proportions of a pattern projected onto a surface located in front of the vehicle the driver can estimate the distance to the object with a good degree of reliability. Sensing of the bearing can also involve a decision as to whether a detected object is in front of the motor vehicle in the direction of travel. If this is the case the control unit should produce a third light distribution. In the simplest case the third light distribution can be obtained in that both aforementioned lights are operated in the second operating condition. However, it is also conceivable to provide a third operating condition for both lights. 
         [0015]    The bearing of the objects can be simply illustrated to the driver in that the orientation of the light-dark boundaries in the second and the third operating condition is different in each case. This task is also solved by the operational method carried out by the above-described parking assistance system, more particularly by a method of supporting the parking of a motor vehicle. The bearing of an object in the vicinity of the motor vehicle is sensed. The distribution of light emitted by the motor vehicle&#39;s light system into the surrounding area is controlled by way of the sensed bearing. According to a further embodiment the task is solved by a computer program product which includes instructions that when executed on a computer implement the afore-described method. The present disclosure also contemplates a non-tranitory computer-readable medium on which program instructions are recorded which enable a computer to implement the above-described method. 
         [0016]    A further subject matter is a device for supporting the parking of a motor vehicle configured to sense the bearing of an object in the vicinity of the motor vehicle; and control, by way of the sensed bearing, the distribution of light emitted by the motor vehicle&#39;s light system into the surrounding area. Such a device can in particular be in the form of a computer on which the above-described computer program product can be implemented. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements. 
           [0018]      FIG. 1  shows a motor vehicle equipped with a parking assistance system according to the present disclosure in a typical usage situation; 
           [0019]      FIG. 2  shows an example of time modulation of light from a lamp of the motor vehicle in  FIG. 1 ; 
           [0020]      FIG. 3  shows a second example of time modulation; 
           [0021]      FIG. 4  schematically shows a spatial light distribution according to a first, simple embodiment when approaching an object on the right-hand side of the motor vehicle; 
           [0022]      FIG. 5  shows a light distribution when approaching an object on the right-hand side of the motor vehicle according to a second embodiment; 
           [0023]      FIG. 6  shows a light distribution when approaching an object on the right-hand side of the motor vehicle according to a third embodiment; 
           [0024]      FIG. 7  shows a light distribution when approaching an object in front of the motor vehicle according to a further development of the third embodiment; 
           [0025]      FIG. 8  shows a light distribution according to a fourth embodiment; and 
           [0026]      FIG. 9  shows a light distribution according to a fifth embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description. 
         [0028]      FIG. 1  schematically shows a view from above of a motor vehicle  1  when parking in a garage  2 . The motor vehicle  1  reaches the garage  2  on a curved path symbolized by an arrow  3 . The width of the garage  2  is narrow; so that there is sufficient space to get out on the driver&#39;s side, the driver steers the motor vehicle  1  close to the right-hand wall of the garage  4  and must ensure that he does not scrape against it. On the one hand, the driver must bring the motor vehicle  1  to a standstill close enough to the end wall  5  of the garage in order to be able to close the garage door and on the other hand the motor vehicle  1  must not come into contact with the end wall  5 . 
         [0029]    If the motor vehicle  1 —in contrast to the case considered in  FIG. 1 —has the steering wheel on the right, the driver will normally try to park it by the left-hand garage wall  6 . When coming from the direction indicated with the arrow  3 , the driver passes the garage door close to a left door post  7  and when he then steers the motor vehicle into a position parallel to the wall  6  there is the possibility of a rear part of the motor vehicle body coming into contact with the left door post  7 . 
         [0030]    In order to reliably prevent contact with the walls  4 ,  5 ,  6  of the garage  2  or other objects in the area surrounding the vehicle  1 , the motor vehicle  1  is equipped with a parking assistance system. A monitoring unit  8  of this parking assistance system includes at least one proximity sensor  9  and a central processor  10  for evaluating signals from the proximity sensor  9 . A single direction-resolving proximity sensor can be provided to monitor the area surrounding the motor vehicle  1 . The proximity sensors  9  can be of any known type of senser e.g. a radar sensor or an intra-red sensor. 
         [0031]    In the case illustrated here three proximity sensors  9  are distributed on the front, right and left side of the motor vehicle  1  in order to monitor a surrounding area (shown hatched in  FIG. 1 ) along the left side  11  of the motor vehicle  1 , in front  12  of the motor vehicle  1  and along the right side  13  of the motor vehicle respectively. Another proximity sensor  9  can be provided on rear of the motor vehicle. This has no function as long as the motor vehicle  1  is moving in a forward direction as in  FIG. 1 . However, when a reverse gear is engaged, the rear sensor may supercede the function of the front sensor in order to now monitor the surrounding area lying ahead of the motor vehicle  1  in the direction of travel. 
         [0032]    The motor vehicle  1  is equipped in with pairs of front headlights  14  and indicators  15 . If the driver has activated the monitoring unit  8  in order assist parking, the front headlights  14  and/or indicators  15  are controlled by the monitoring unit  8 . The monitoring unit  8  can also be connected to a loudspeaker in order to provide the driver with audible feedback in a known manner through acoustic signals about the distance to an object, in this case the garage wall  4 , detected in one of the surrounding areas  11 ,  12 ,  13 . 
         [0033]      FIG. 2  shows the change in intensity of the front headlights  14  when parking the motor vehicle  1  along arrow  3  according to a first embodiment of the present disclosure. Over the entire path the surrounding area  11  on the left-hand side of the vehicle  1  is free of detected objects. Therefore the left front headlight  14 , as shown by a straight line  14 L in  FIG. 2 , is operated with constant intensity. As shown by the curve  14 R, the right front headlight  14  is operated with the same intensity until at time t 1  the right garage wall  3  enters the right surrounding area  13 . The right front headlight  14  then starts flashing at a first, low frequency in order to alert the driver to the danger that is present. If at a time t 2  the distance to the wall  4  is less than a first limit value the frequency of flashing is increased. This can be repeated one or more times, for example at time t 3  in the event of distance limit values are undercut. On undercutting a last limit value at time t 4  the right front headlight  14  is switched off completely in order to warn the driver in an unmistakable manner. 
         [0034]    The indicators  15  can be controlled together with the front headlights  14  or instead of these in the manner described with reference to  FIG. 2 . In the case of the indicator, on undercutting the last limit value, instead of being completely switched off, continuous operation can be considered. 
         [0035]    Switching between dipped or low beam operation and full or high beam operation can also be considered for indicating the danger. For example, when the motor vehicle  1  drives into the garage  2  with the front headlights  14  may be operated in dipped beam mode. When the garage wall  4  comes into the surrounding area  13 , the right front headlight  14  initially starts to slowly switch between full and dipped beam and then with increasing frequency as the motor vehicle approaches the wall  4 . 
         [0036]    Instead of the frequency or together with it, the pulse frequency of a flashing light, front headlight  14  or indicator  15  can also be varied depending on the distance of the motor vehicle  1  to a detected object. According to  FIG. 3 , the pulse frequency becomes smaller and smaller with increasing proximity to the wall  4  and at the same time the light flashes become brighter in order to achieve an at least constant brightness on average, and at the same time give rise to the impression of increasing urgency. 
         [0037]      FIG. 4  shows the garage  2  as seen from the perspective of the driver of the motor vehicle when the motor vehicle is in the position shown in  FIG. 1 . Of the motor vehicle  1 , only a front section is schematically shown with headlights  14  which are hidden from the driver&#39;s view by the hood of the vehicle. On the end wall  5  light beams  16  of the front headlights  14  can be seen. The left light beam  16  is continuously switched on, the right one flashes in order to indicate the critical proximity of the motor vehicle  1  to the right garage wall  4 . As the front headlights  14  do not directly illuminate the side walls  4 ,  6  of the garage  2  these are relatively dark, therefore for a driver it is very noticeable if in accordance with one modification, the processor  10  controls an indicator  15  mounted on the side of the motor vehicle  1 , e.g. on an outside mirror  17  (see  FIG. 1 ), in order to indicate that the wall  4  has been detected in the surrounding zone  13  and a light beam  18  from the indicator hits the garage wall  4 . 
         [0038]      FIG. 5  shows a light distribution in the garage  2  according to a second embodiment of the present disclosure. According to this embodiment the front headlights  14  of the vehicle are adaptive frontlight system (AFS) headlights which when driving on the open road follow the angle of the steering wheel in a known manner. If the driver has activated the monitoring unit  8 , the coupling of the alignment of these headlights  14  to the steering wheel position is released. As long as no objects are detected in the surrounding areas  11 - 13  of the motor vehicle  1 , the headlights are orientated straight head in a fixed manner. If the right garage wall  4  enters the monitored area of the vehicle  1  and is detected by the monitoring unit  8 , this causes the front headlight  14  to perform a swinging movement so that its light beam  16  moves back and forth on the garage wall as shown by a double arrow in  FIG. 5 . The frequency of the swinging movement can be varied as a function of the sensed distance to the wall  4  and equally it is possible, as described with reference to  FIG. 2 or 3 , to modulate the intensity of such a front headlight  14  in accordance with the distance. 
         [0039]      FIG. 6  relates to a third embodiment of the present disclosure according to which the front headlights  14  are matrix headlights, each with a plurality of elemental light sources, in particular LEDs, which can be controlled independently of each other, and the light beams  16  of these front headlights, as indicated in the figure, include light beams of the elemental light sources extending next to each other in a matrix-like manner. In this embodiment the monitoring unit  8  reacts to detecting the entry of the garage well  4  into the surrounding area  13  by switching off a column of elemental lights of the right headlight  14 . In this way, the light beam  16  divides into two parts  20 ,  21  separated by a vertical dark strip  22 . The width of the dark strip  22  on the walls of the garage  2  depends on the distance between the walls and the headlight  14 . Independent of the distance on the other hand is the opening angle  14  on the headlight between the light-dark boundaries  23  on both sides of the dark strip  22 . If the vehicle  1  approaches the wall  4  more closely so that a first distance limit value is undercut, a further column of elemental light sources is switched off and the width of the dark strip  22  or opening angle (α) increases. By comparing the width of the dark strip  22  with the overall width of the light beam  14  the driver can estimate the distance to the wall  4 . 
         [0040]    If, on entering the garage  2 , the motor vehicle  1  keeps a sufficient distance from both side walls  4 ,  6 , the light beams remain complete until the end wall  5  moves into the surrounding area  12  in front of the motor vehicle  1 . Approaching the end wall  5  can be signalled to the driver in that a dark strip  22 , as shown in  FIG. 6 , is produced in both light beams  18 . More advantageous, however, is the type of control shown in  FIG. 7 . As a result of the smaller distance of the motor vehicle  1  from the end wall  5 , the light beams  18  appear smaller here than in  FIG. 6  but their proportions are unchanged. Detecting of the front wall  5  in the surrounding area  12  head results in the switching off of elemental light sources of both front headlights  14  line by line so that in each of the light beam  18  a dark strip  24  with horizontal light-dark boundaries  25  appears. The closer the vehicle  1  gets to the end wall  5  the more lines are switched off and the greater the opening angle β of the dark strip  24  becomes. 
         [0041]    In the event of simultaneously approaching the end wall  5  and one of the side wall  4 ,  6  it is conceivable to switch off columns and lines of elemental light sources in the headlight  14  adjacent to the relevant side wall and therefore produce horizontal and vertical dark strips that cross each other. 
         [0042]    According to yet another type, the use of matrix headlights as front headlights  14  allows a critical approach to be indicated to the driver. In  FIG. 8  switched off elemental light sources of the right headlight  14  produce the images of an arrow in its light beam  16 , in this case an arrow  26  pointing to the left, which immediately makes it clear to the driver in which direction he should steer. If the number of elemental light sources of the headlight so permits, the distance to the wall can be made visible to the driver by the size of the arrow  26 . However, also conceivable is a flashing visualization of the arrow  26  with a frequency dependent on distance or pulse frequency dependent on distance as mentioned with reference to  FIG. 2, 3 . Approaching of the end wall  5  can be visualised by downward pointing arrows in both light beams  18 , and simultaneous approaching of the end wall  5  and a side wall by an arrow obliquely pointing to the middle. 
         [0043]    A maximum degree of convenience for the driver is achievable if in addition to the headlights  14  and indicators  15  the motor vehicle  1  also has a lamp in the form of a projector  27  (see  FIG. 1 ), e.g. a DLP projector with which images contents can be projected. Such a projector  27  can be used when travelling on the open road to project directions of a satellite navigation system, pictures of traffic signs or suchlike onto the roadway in front of the motor vehicle  1 . In the context of the present disclosure the projector  27  can be used, as shown in  FIG. 9 , to project in the direction of travel quantitative information about the measured distance to objects in the surrounding area  11 ,  12 ,  13 . In  FIG. 9  the image projected by the projector  27  includes three parts  28 ,  29 ,  30  which respectively correspond to areas  11 ,  12 ,  13 . 
         [0044]    In this way the driver recognizes on part  30  that the distance to the right garage wall  4  is currently  15  cm and on part  29  that the distance to the end wall  5  is  60  cm. The indication “&gt;1 m” in part  28  shows that the distance to the left garage wall  6  is so large that it is still outside the monitored area  11  and that no valid measurement of its distance is available. If no object is detected in the monitored area the corresponding part of the projected image, i.e. part  28  in this case, can also remain dark. 
         [0045]    While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents.