Abstract:
Methods and apparatus are provided for reducing the occurrence of vehicle door bumps against an adjacent object facing the door. The apparatus comprises one or more distance sensors mounted on the vehicle for measuring distance D from the door to the object, a brake for inhibiting outward movement of the door toward the object, a warning system and a controller coupled to the distance sensors, warning system and brake for applying the brake to inhibit further outward movement of the door when D≦D(MIN), a predetermined minimum distance away from the object. In a preferred embodiment, a first driver warning is activated when the initial door-to-object spacing D(INIT)≦D(SAFE), the maximum outward door reach. A second warning is desirably added when the door begins moving toward the object or has reached about (D(INIT))/2 and a third warning is activated when the brake is engaged.

Description:
TECHNICAL FIELD  
       [0001]     The present invention generally relates to an apparatus and method for protecting doors, and more particularly to an apparatus and method for reducing risk of a vehicle door striking a nearby object when opened.  
       BACKGROUND  
       [0002]     When a vehicle is along side another vehicle or object there is always the risk that if the vehicle door is opened it may bump the adjacent object or vehicle, thereby causing damage to one or both. It is common to apply edge guards to vehicle doors to reduce the severity of such bumps. However, this does not prevent the bump but merely cushion it so that it is less likely to cause damage. Nonetheless, even with the use of door edge guards, damage to the user&#39;s vehicle or to the other vehicle or object can still result. The cost of repairing such damage is significant.  
         [0003]     Accordingly, it is desirable to provide an apparatus and method whereby the vehicle user is warned that his or her door is undesirably close to a nearby vehicle or object. In addition, it is desirable to provide a graduated warning depending upon the likelihood of his or her door contacting the nearby vehicle or object. Still further it is desirable that when impact is imminent, that door movement be inhibited so as to further reduce the likelihood of impact. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.  
       BRIEF SUMMARY  
       [0004]     An apparatus is provided for reducing the occurrence of vehicle door bumps against an adjacent object facing the door. The apparatus comprises one or more distance sensors mounted on the vehicle for measuring distance D from the door to the object, a brake for inhibiting the outward movement of the door toward the object, and a controller coupled to the distance sensors and the brake for applying the brake to inhibit further outward movement of the door when D&lt;D(MIN), a predetermined minimum distance away from the object. In a preferred embodiment the controller activates a first driver warning when the initial door-to-object spacing D(INIT)&lt;D(SAFE), the maximum outward door reach absent the object. A second warning is desirably added when the door begins moving toward the object or has reached about (D(IT))/2 and a third warning is added when the D reaches ˜D(MIN) and the brake is activated. The warning system desirable includes both audible and visual alarms.  
         [0005]     A method is provided for reducing the likelihood of a bump between a vehicle door and an adjacent object facing the door. The method comprises, measuring distance D between the door and the object, comparing D(INIT) to D(SAFE) where D(INIT) is the distance to the object before the door is opened and D(SAFE) is a distance from the vehicle reached by the door at its maximum possible outward movement absent the object, and determining whether the door is moving toward the object, and if so turning on a warning. Preferably, the method further comprises determining when the distance D&lt;D(MIN) where D(MIN) is a predetermined minimum value, and then engaging a brake to inhibit further outward movement of the door. In a further embodiment, a further warning is turned on before or after the engaging step.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and  
         [0007]      FIG. 1  is a simplified drawing of two adjacent vehicles, illustrating a door swing detection and protection system according to the present invention;  
         [0008]      FIG. 2  is a simplified electrical schematic diagram of the system of the present invention;  
         [0009]      FIG. 3  is a simplified flow chart illustrating the method of the present invention according to a first embodiment; and  
         [0010]      FIG. 4  is a simplified flow chart of the method of the present invention according to a second embodiment showing further details. 
     
    
     DETAILED DESCRIPTION  
       [0011]     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 expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. The suffix “(s)” is used herein to indicate that there are one or more of the particular objects or functions being discussed, depending upon the circumstances. For example and not intended to be limiting, the word “sensor(s)” indicates that there are one or more sensors, “warning(s)” indicates that there are one or more warnings, and so forth. Further, as used herein, the word “driver” is intended to include any door user in the vehicle and not be limited merely to the person behind the steering wheel.  
         [0012]      FIG. 1  is a simplified drawing of adjacent vehicles  20 ,  22 , illustrating door swing detection and protection system  21  mounted on vehicle  22 , according to the present invention. Vehicle  22  has door  24  that pivots around door hinge  26  by angle  28  and with radial extent  30 . Distal door edge  32  follows a path along circle  34  where, unless prevented, it will strike car  20  at location  36 . As will be subsequently explained in more detail, conveniently associated with or close to hinge  26  are door angle measuring unit  38  and door brake  40 . In the preferred embodiment door  24  has sensor  42  mounted at or near distal door edge  32  for measuring distance  44  between distal door edge  32  and vehicle  20 . Sensor  42  is preferably a type that uses radiative signals and echoes  43  to measure distance  44 . However, this is not essential and any type of proximity sensor able to detect the change in position of door edge  32  with respect to vehicle  20  may be used. The same applies to sensor  46 . Similar sensor  46  is conveniently but not essentially mounted on body  23  of vehicle  22  rather than on door  24 , for measuring separation distance  48  using radiative signals and echoes  45 . Sensor  46  maybe used in place of or in addition to sensor  42 . Signals  43 ,  45  may be electromagnetic or acoustic or a combination thereof.  
         [0013]     Warning system  48  is desirable provided within vehicle  22  to alert the vehicle user (hereafter the “driver”) that there is a danger of door  24  striking vehicle  20 . While object  20  is identified as a vehicle, this is merely for convenience of description and not intended to be limiting. Vehicle  20  represents any type of nearby object that door  24  might strike when opened. While sensors  42  and  46  are shown in  FIG. 1  as protruding slightly from vehicle  22 , this is merely for convenience of illustration. It is desirable that sensors  42 ,  36  be recessed and not significantly protrude from the surface of vehicle  22 . In this way they are less likely to be damaged by door strikes or other familiar driving and parking mishaps. A protective cover substantially transparent to signals  43 ,  45  being emitted and received by sensors  42 ,  46  may also be used.  
         [0014]      FIG. 2  is a simplified electrical schematic diagram of control system  50  according to the present invention. System  50  comprises door system sensor(s)  52  including door distance sensor(s)  521  (abbreviated as “DIS”), optional door angle sensor(s)  522  (abbreviated as “ANG”), and optional door pull sensor(s)  523  (abbreviated PUL). Distance sensor(s)  521  can include either or both of door-mounted sensor  42  and/or body-mounted sensor  46 . Door angle sensor(s)  522  can include angle sensor  38  of  FIG. 1 . Door pull sensor(s)  523  can include door pull sensor  39  of  FIG. 1 . The purpose of distance sensor(s)  521  is to measure the distance D from door edge  32  to vehicle or object  20  of  FIG. 1 . The purpose of angle sensor  522  is to measure angle  28  of  FIG. 1 . The purpose of sensor  523  is to measure whether an inward (e.g., a “pull”) or outward directed (e.g., a “push”) force or torque is being exerted on door  24  by the driver. For example, being able to detect an inward directed force or torque being applied to door  24  is useful in deciding when to release door brake  40 . Distance, angle sensors and torque sensors are well known in the art.  
         [0015]     System  50  also comprises controller  56  coupled to sensor(s)  52  by leads or bus  53 , warning system  48  (abbreviated as “WARNING”) coupled to controller  56  by leads or bus  49 , door brake  40  coupled to controller  56  by leads or bus  41 , disable switch  58 , memory  62  coupled to controller  56  by leads or bus  63 , vehicle sensor(s)  60  coupled to controller  56  by leads or bus  61 . Sensor(s)  60  are useful for determining whether vehicle  22  is in motion or stopped and may be a part of the vehicle&#39;s drive-train control system or other vehicle electronics system. Disable switch  58  can be coupled to controller  56  by leads or bus  55  or coupled between door brake  40  and controller  56  as shown by the dashed outline  58 ′ in lead or bus  41 . Either arrangement is suitable. Disable switch  58 ,  58 ′ permits the user to temporarily shut-off or inhibit operation of door guard system  21 ,  50 . This can be done by temporarily disabling controller  56  through lead or bus  55  or by preventing “brake door” signals from activating brake  40  by interrupting lead or bus  41 . In the latter mode, the disable switch is located between controller  56  and door brake  40  as shown by dashed outline  58 ′. In this situation, system  50  would continue to provide the various user warnings discussed below but the door brake would not engage to prevent door  24  from bumping nearby object  20 . Warning system  48  desirably includes audible warning unit  48   i , visual warning unit  482  and access to horn  483 . While both audible warning unit  481  and visual warning unit  482  are desirable, both are not necessary and one type of warning be used can alert the driver of vehicle  22  to the risk of a door bump.  
         [0016]     Distance D between door edge  32  and adjacent vehicle or object  20  (identified by reference number  44 ) can be measured directly by sensor  42  either alone or in cooperation with the controller  56 . Alternatively, distance D can be approximately calculated by using sensor  46  alone or in cooperation with controller  56  to measure distance  47  and using angle sensor  38  to determine door angle  28 . Knowing distance  47 , door radius  30  and door angle  28 , controller  56  can approximately calculate distance D from door edge  32  to adjacent vehicle or object  20 . While useful, this approach is less accurate than using sensor  42  directly, since it is affected by angle  27  by which side  25  of vehicle of object  20  is not substantially parallel to vehicle  22 . The greater angle  27 , the larger the potential error. In  FIG. 1 , sensor  46  is shown as being located aft of door  24 , but this is merely to avoid an excess of crowded lines in the figure. Locating sensor  46  on vehicle body  23  longitudinally about where the midpoint of door radius  30  would be found (e.g., about at location  46 ′) reduces the potential error due to vehicle or object  20  being cocked with respect to vehicle  22 . Sensor  46  is desirably attached to body  23  of vehicle  22  and does not move with door  24 .  
         [0017]     Door brake  40  is conveniently mounted on or associated with hinge  26  as a hinge brake. Door hinge brakes are well known in the art. While a hinge brake is useful it is not essential and any type of unit that can slow and/or temporarily stop outward movement of door  24  is useful. For example and not intended to be limiting, door brake  40  may be an electrically activated unit that applies a disk or band or drum brake to a rotating member coupled to hinge  26  so as to slow and/or stop further outward movement of door  24 . A further alternative employs an arc-shaped piece or a hinged linkage coupled to the door that moves out and in as the door opens and closes, passing between braking pads which can slow and/or stop further movement of the door by clamping the piece with electrically actuated brake pads. A still further example is an over-run clutch type of unit coupled to the hinge or the door or elsewhere and having a pawl that can be engaged by controller  56 . When the pawl engages the over-run clutch it stops further outward rotation of the door. But because the over-run clutch is unidirectional the door can swing inward or close without difficulty. Any suitable system for braking door movement may be used and are intended to be included in the present invention. It is preferable but not essential that the door braking action be unidirectional, that is, inhibiting or stopping outward movement when needed to prevent contact with the adjacent object, but not prevent inward movement to re-close the door. While electrical actuation of the braking mechanism is preferred, any means of doing so can be used. Non-limiting alternatives are hydraulic or pneumatic actuation or a combination there along with electrical actuation.  
         [0018]     It is presumed in the discussion that follow, that system  50  through the cooperation of sensors  52  and controller  56  provides substantially continuous or frequently updated values of distance D between door  24  and adjacent object or vehicle  20 , so that is unnecessary to expressly include “measure D” and/or “calculate D” steps in the methods of  FIGS. 3-4 , such steps being understood by persons of skill in the art based on the description herein.  FIG. 3  is a simplified flow chart illustrating method  100  of the present invention according to a first embodiment. Method  100  begins with START  101 , that desirably occurs when the ignition switch or other vehicle enabling device is turned on, or each time the vehicle stops or the door closes or a combination thereof. Method  100  then causes controller  56  operating in conjunction with sensor(s)  60  to execute VEHICLE STOPPED ? query  102 . If the outcome of query  102  is NO (FALSE) then method  100  returns to START  101  as shown by path  103 . If the outcome of query  102  is YES (TRUE), then controller  56  in combination with sensors  52  executes INTIAL DISTANCE TOO CLOSE ? query  104  to determine whether or not the vehicle is initially too close to another object, as for example, object or vehicle  20  located alongside. Query  104  can be executed (see  FIG. 1 ) by determining whether the product of door length  30  and the cosine of the maximum value (door open all the way) of angle  28  equals or exceeds distance  47  (or distance  44  measured with door  24  still closed). The variable “D” is used herein to represent distance  44  between door edge  32  and adjacent object or vehicle  20 . Thus, D can vary from D=D(INIT), the initial value with door  24  closed, to D=D(MIN), the minimum predetermined value just before a door bump takes place.  
         [0019]     If the outcome of query  104  is NO (FALSE) then method  100  proceeds to END  106  as shown by path  105 . If the outcome of query  104  is YES (TRUE) indicating that a door bump is possible, then method  100  proceeds to FIRST WARNING ON step  108  wherein controller  56  operating in conjunction with warning system  48  causes a first level warning to be turned on to alert the driver to a potential door bump risk. For example, and not intended to be limiting, controller  56  can cause visual display unit  482  in the field of view of the driver to flash a cautionary message with an appropriate color and repetition rate. Other warnings can also be given, for example and not intended to be limiting, audible warning unit  481  can be used to sound a buzzer or tone or speak, for example, “Be careful when you open your door. There is another object close by.” or give other audible warning, as may be desired by the system designer and/or user. In the preferred embodiment, the first warning is merely visual but this is not essential. Recorded messages such as that illustrated above can be digitally stored in memory  62  associated with controller  56  or elsewhere in the vehicle electronic system.  
         [0020]     Following step  108 , method  100  causes controller  56  acting in cooperation with sensors  52  to execute DOOR APPROACH[NG OBJECT ? query  110  to determine whether or not the door is approaching the nearby object. For example this can be done by comparing the current value for distance  44  with previous values, i.e., is distance  44  getting smaller, or alternatively, is angle  28  getting bigger, or both. If the result of query  110  is NO (FALSE) then method  100  returns to step  108  as shown by path  111 , leaving the first warning on. If the outcome of query  110  is YES (TRUE), then method  112  advances to SECOND WARNING ON step  112  wherein the warning level is increased. It is desirable (but not essential) that the first warning, whether audible or visual, is continued and an additional warning added. Suppose for example, that the first warning is a flashing light or visual message via visual alarm unit  482 , then the second warning would desirably add an audible warning indication (buzzer, tone, voice) using audible warning unit  481 , or vice versa. The combination of controller  56  and sensor(s)  52  then executes DOOR APPROACHING IMPACT ? query  114 . If the outcome of query  114  is NO (FALSE) then method  100  returns to step  112  as shown by path  115 . If the outcome of query  114  is YES (TRUE), then method  100  causes the combination of controller  56 , warning system  48  and door brake  40  to execute THIRD WARNING ON step  116  and ENGAGE DOOR BRAKE step  118 , in either order. In step  116 , a still more urgent condition is announced by warning unit  48 . For example and not intended to be limiting, the audible warning tone or buzzer or voice can be increased in volume or begin warbling or speak a difference message (e.g., “Watch out! Watch out! Door bump imminent on the left/right!”, etc.). Similarly, the visual indication can change color (e.g., yellow or orange to red) or begin flashing more brightly and more urgently, or a combination thereof. Or, system  50  can provide a combination of increased audible and visual effects to alert the driver that a door bump is imminent.  
         [0021]     In step  118 , system  50  engages door brake  40  by sending an appropriate signal along leads or bus  41  from controller  56 . Engaging door brake  40  desirably prevents the driver from pushing the door open the last small distance D(MIN) where it will bump the adjacent vehicle or object. This last small distance D(MIN) at which the door brake is engaged in step  118  is conveniently in the range of about 1 to 30 cm, better in the range of about 1 to 15 cm and preferable in the range of about 1 to 2 cm. D(MIN) is the value of distance  44  at which controller  56  causes door brake  40  to engage, thereby halting or significantly inhibiting further swing-out of door  24 . D(MIN) is conveniently stored in memory in controller  56  or elsewhere in the vehicle&#39;s electronic system accessible to controller  56 . While it is desirable that door brake  40  halt further swing-out of door  24  at D(MIN), this is not essential. Door brake  40  may act to gradually apply greater and greater braking action as D(MIN) is approached so that the swing-out velocity of door  24  is reduced to near zero by the time distance  44  approaches D(MIN). It is desirable that the maximum braking force be applied to halt door  24  before distance  44  reaches zero so that a door bang is avoided. Either sudden or gradual application of door brake  40  is useful. By accessing sensor  523 , system  50  can determined when the driver pulls the door inward and thereafter release brake  40 . Or, if brake  40  employs an over-run type clutch brake, door  24  can swing closed without further action by controller  56 . Following step  118 , method  100  goes to END  106 . Method  100  desirably repeats each time door  24  is closed or vehicle  22  stops or starts.  
         [0022]      FIG. 4  is a simplified flow chart of method  200  of the present invention according to a further embodiment and showing further details. Where the same or similar steps occur as in  FIG. 3 , such steps are identified. Method  200  is preferably executed by system  50  of  FIG. 2 , but other electronic processing systems within the car may also be used. For convenience of explanation, references to which portions of system  50  perform which steps is omitted in the description of  FIG. 4  since this is covered sufficiently in connection with  FIG. 3  so that persons of skill in the art will understand based on the description therein how such steps are executed by system  50 . Method  200  begins with START  201  analogous to start  101  of  FIG. 3  and under substantially the same conditions as START  100 . Initial VEHICLE STOPPED ? query  202  is then executed wherein it is determined whether or not vehicle  22  is stopped. If the outcome of query  202  is NO (FALSE), then method  200  returns to start  201  in the same manner as method  100  of  FIG. 3 . If the outcome of query  202  is YES (TRUE) then method  200  proceeds to D(INIT)≦D(SAFE) query  204  analogous to query  104  wherein it is determined whether or not D(INIT), the initial value of D with door  24  still closed, is less than D(SAFE) defined as the distance from vehicle  22  to edge  32  of door  24  when door  24  is in its maximum open position absent object of vehicle  20 . That is when angle  28  has its maximum possible value. D(SAFE) is a known constant for each vehicle door. If D(INIT)&gt;D(SAFE), then adjacent vehicle or object  20  is far enough away that door  24  will not strike it when swung to its maximum open position. Thus, if the outcome of D(INIT)≦D(SAFE) query  204  is NO (FALSE), then method  200  loops back as shown by path  205 . If the outcome of query  204  is YES (TRUE), then method  200  proceeds to FIRST WARNING STEP  206  analogous to step  108 , wherein a first warning is given to the driver via warning system  48  as described in connection with step  108 . Following step  206 , method  200  advances to D&lt;D(X) query  212  generally analogous to step  110 . The value D(X) lies between D(MIN) and D(INIT), that is, D(MIN)&lt;D(X)&lt;D(INIT) and can be chosen by the system designer to suit the characteristics of a particular vehicle or can be made dependent upon the particular situation of vehicle  22 . In a preferred embodiment, D(X) is set to about one-half of D(INIT), but larger or smaller values can also be used. Setting D(X)=(D(INIT))/2 causes subsequent SECOND WARNING ON step  214  (analogous to step  112 ) to occur when door  24  is about half way to bump into object or vehicle  20 , but other criteria can also be used. If the outcome of query  212  is NO (FALSE), then method  200  loops back to D=D(INIT) ? query  208  (has the door re-closed?) as shown by path  213 . If the outcome of query  208  is NO (FALSE) then method  200  loops back to step  206  as shown by path  207 . If the outcome of query  208  is YES (TRUE), indicating that door  24  is once again closed (D has returned to its initial value) then method  200  advances to DECREASE WARNING step  210  wherein the first warning level is turned off and method  200  returns to query  204  as shown by path  211 . If the outcome of query  204  is still YES (TRUE), then the first warning level is turned back on in step  206 , as before. If door  24  is never opened further so that D&lt;D(X) does not occur, then method  200  will proceed around the loop  204 ,  206 ,  212 ,  208 ,  210  and the first warning level will turn on and off with every excursion around the loop. Where the loop execution time is rapid as is usually the case, the first warning will appear to be on substantially continuously as long as D(INIT)&lt;D(SAFE).  
         [0023]     Returning now to query  212 , if the outcome of query  212  is YES (TRUE), then method  200  proceeds to SECOND WARNING ON step  214  equivalent to step  112  of method  100 , wherein the second level of driver warnings is turned on, as has been previously described in connection with step  112  of method  FIG. 3 . Following step  214 , D=D(MIN) ? query  216  is executed, analogous to query  114  of  FIG. 3 . D=D(MIN) is the predetermined distance away from impact when it is desired that maximum door braking occur to try to avoid a door bump. If the outcome of query  216  is NO (FALSE) then method  200  loops back as shown by path  217  to D&gt;D(X) ? query  218  wherein it is determined whether or not door  24  has closed sufficiently so that D is now greater than D(X). If the outcome of query  218  is NO (FALSE), then method  200  loops back to step  214  as shown by path  219 . If the outcome of query  218  is YES (TRUE), then method  200  advances to DECREASE WARNING step  220  wherein the second warning is turned off, and thereafter loops back to step  212  as shown by path  221 . When step  212  is repeated, if the outcome is NO (FALSE), for example because the driver has closed the door, then methods  200  returns to query  204  as previously described.  
         [0024]     If the outcome of query  216  is YES (TRUE), then method  200  advances to THIRD WARNING ON step  222  (equivalent to step  116 ) and ENGAGE DOOR BRAKE step  224  (equivalent to step  118 ), which may be performed in either order. As previously discussed engaging door brake  40  substantially stops door  24  from opening further and therefore prevents a bump or at least slows door  24  sufficiently that a bump is unlikely to cause damage. Following steps  222 ,  224  method  200  advances to D&gt;D(MIN) query  226  wherein it is determined whether the driver has begun or is trying to re-close door  24 . If the outcome of query  226  is NO (FALSE) then method  200  loops back to steps  222 ,  224  as shown by path  227 . If the outcome of query  226  is YES (TRUE) indicating that the driver is at least trying to re-close the door, then method  200  advances to RELEASE DOOR BRAKE step  230  and DECREASE WARNING step  232 , which may be performed in any order. Sensor  523  in  FIGS. 2 and 39  in  FIG. 1  is provided to sense when the driver exerts a closing force on door  24  when a simple brake is being employed. When an over-run brake is being used, sensor  523 ,  39  is not generally needed since the door will close with little effort. DECREASE WARNING step  232 , removes the third warning level established in step  222  and thereafter method  200  loops back to query  216  as shown by path  233 . If for example, the driver has closed the door after feeling brake  40  engage, then method  100  loops back via steps  216 ,  218 ,  221 ,  212 ,  208 ,  210  to initial query  204 , successively turning off each warning level. The first warning level may come back on depending upon the outcome of query  204 . Thus, method  200  automatically increases and reduces the warning levels as the driver moves the door open and closed so that the warning level is always appropriate to the position of the door relative to vehicle  20 . Persons of skill in the art will understand based on the description herein that methods  100  and  200  apply to any vehicle door and any user of such door. The present invention also applies to doors on any other type of equipment, craft or structure that may be in proximity to an adjacent vehicle, craft, object or structure where door bumps are desired to be avoided. As used herein, the word “vehicle” whether singular or plural is intended to include such other crafts, objects, equipment or structures where there is a risk of door bumps.  
         [0025]     While the foregoing description of the present invention is given in terms of a single-sided door swing inhibiting system, this is merely for convenience of explanation and persons of skill in the art will understand that multiple doors on either or both sides of the vehicle may be equipped with system  21 ,  50  of the present invention. Under those circumstances, controller  56  and warning system  48  are desirably shared, that is, used by all the doors equipped with sensors and door brakes, but this is not essential. Also, doors on the same side of the vehicle, can share body mounted distance sensor  46 .  
         [0026]     Further, returning to  FIGS. 2-3 , when DOOR APPROACHING OBJECT ? query  110  or D≦D(X) query  212  is executed and it is found that distance  44  is getting smaller but angle  28  remains unchanged, this is an indication that a person in adjacent vehicle  20  may be opening his or her door under circumstances (determined in initial query  104 ) where the initial distance is too close, that is D(INIT)&lt;D(SAFE). Under these circumstances it is appropriate that system  50  provide an external warning to alert the other person to be careful by, for example, sounding horn  483 . Other external warnings can also be used. The external warning may also be accompanied by an internal warning to alert the driver of vehicle  22  to the situation. Thus, the system of the present invention can not only warn the warn the user of the car equipped with the present invention that he or she has a risk of causing a door bump with an adjacent vehicle, but can also generate an alert or warning that a person in the adjacent car may be about to cause his or her door to bump the user&#39;s car. This is a significant advantage of the present invention.  
         [0027]     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 the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.