Abstract:
The present system relates to driver-assistance systems providing a parking-assistance functionality, in which a vehicle brake system is actively controlled. Among other components, the parking assistance system includes a parking device for implementing a parking operation along a calculated parking trajectory, and an output device for outputting distance information about detected objects to a man-machine interface. The parking device is configured to brake only for the at least one parking-space-delimiting object (PLBO) detected prior to the parking operation, but not for a non-parking-space-delimiting object (non-PLBO) detected in the course of the parking operation. The output device is configured to output to the MMI only distance information about the non-PLBO, but no distance information about the PLBO during the parking operation.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to driver-assistance systems, especially systems providing a parking-assistance functionality, in which a vehicle brake system is actively controlled. 
       BACKGROUND INFORMATION 
       [0002]    A parking-assistance functionality supports the driver in parking a vehicle. In so doing, the assistance system measures a parking space while passing it, and then guides the driver into the measured parking space. The guidance may be a passive guidance; in this case, steering angle inputs as well as start-driving and stopping instructions are transmitted to the driver via a user interface or a man-machine interface (MMI). However, guidance may also occur in active form, in which case the driver receives only start-driving or stopping inputs, while the system assumes the transverse and longitudinal guidance. Corresponding systems are discussed, for example, in DE 10 2004 047 484 A1 or EP 1 270 367 A2. 
         [0003]    During the parking maneuver the vehicle environment is monitored by distance-measuring sensors disposed in the bumpers, for instance. The distances to obstacles are indicated to the driver and the driver is warned of looming collisions if appropriate. In the case of systems having (semi)automatic longitudinal guidance, brake interventions take place that are aimed at end points of the parking trajectory, i.e., stopping and turning points at the end of a parking space, but also brake interventions aimed at detected static or dynamic obstacles, i.e., suddenly occurring obstacles. 
         [0004]    In DE 60 2004 005 053 T2, a parking-assistance method is discussed in which a temporal change rate of a braking force is modified. In situations in which an obstacle is not stationary but comes closer to the vehicle or moves away from it, this allows for a rapid adaptation of the brake force to the new position of the obstacle. When there is a risk that a moving obstacle will be touched, a red lamp is activated on a dashboard. In this case the driver may decide to step on the brake pedal. 
       SUMMARY OF THE INVENTION 
       [0005]    A driver-assistance system having semiautomatic longitudinal guidance induces a braking operation only with regard to stop or turning points of a previously calculated parking trajectory. The stopping points refer to at least one parking-space-delimiting object (“PLBO”), which had been measured by the sensor system prior to parking, e.g., when driving past the parking space. When entering the parking space, the sensor system verifies the distance to the PLBO and, if necessary, the system adapts the distance still to be covered until reaching the stop. The system does not brake for previously undetected, possibly temporary, i.e., suddenly occurring, obstacles along the parking trajectory. This constitutes an appropriate response in many situations, such as when the temporary object is a person who crosses the parking space in a grazing manner and then immediately departs the space again. However, informing the driver is very important; the MMI of the parking assistance system must inform the driver in clear and directly comprehensible form for which objects the driver must brake on his/her own, and for which objects, such as the at least one PLBO, the system brakes automatically. That is to say, the driver must be enabled to brake himself when the parking assistance system determines that an object is being approached which is not part of the delimitation of the parking space (i.e., a non-parking-space-delimiting object “non-PLBO”), e.g., an obstacle along the parking trajectory, because the system does not brake for a non-PLBO. On the other hand, however, the parking assistance system brakes for the previously detected PLBO(s), and the driver should trust the system in this regard. 
         [0006]    According to the exemplary embodiments and/or exemplary methods of the present invention, a parking assistance system is provided which has an input device for accepting data from a sensor system. The sensor system is set up to detect at least one PLBO prior to the parking operation. In addition, the system has a calculation device for calculating a parking trajectory based on the detected at least one PLBO. The system furthermore is provided with a parking device for performing the parking operation along the calculated parking trajectory. Finally, the system includes an output device for outputting distance information about detected objects to an MMI. The parking device is configured to brake only for the at least one PLBO detected prior to parking during a parking operation, but not for a non-PLBO detected while engaged in parking. The output device is configured to output only distance information relating to the non-PLBO to the MMI, but no distance information for the PLBO during the parking operation. 
         [0007]    As a result, a system is provided in which temporary objects, for example, do not elicit braking interventions, which is the appropriate response in many situations. At the same time, in comparison with conventional systems, an MMI is modified in such a way that the distance to an object such as an obstacle along the parking trajectory, is output only if this obstacle does not constitute the delimitation of the parking space. This enables the driver to quickly and clearly comprehend when he must act on his own, i.e., brake or stop in front of a (temporary) object by himself, if appropriate. 
         [0008]    The output device may also be configured to output the distance information for the non-PLBO, if the non-PLBO is detected as obstacle along the parking trajectory. In one specific embodiment thereof, the output device is developed to output distance information about the non-PLBO if a distance of the non-PLBO is less than a path to be covered during the parking operation until a stopping or turning point of the trajectory used has been reached. That is to say, if a non-PLBO is detected which is closer to the vehicle than the next stopping point, then the driver is informed of this fact. A non-PLBO, for instance, may also be a PLBO detected prior to parking. Particularly situations in which a PLBO is mobile come to mind in this context, in particular. 
         [0009]    The distance output may include a distance warning, which is output to the output device if a drop below a predefined minimum distance has occurred. In this specific embodiment, the non-PLBO is brought to the driver&#39;s attention only if, and not until, a drop below the minimum distance is at hand. This avoids unnecessary warnings, for example. 
         [0010]    Multiple MMIs may be provided, such as an acoustic and an optical interface to the driver. In this case the output device may be set up for outputs to two or more MMIs. Only distance information about the non-PLBO is output to the first one of the two MMIs, e.g., an acoustic MMI, during the parking operation under these circumstances, but no distance information about the PLBO. At the same time, distance information about the PLBO is output to a second MMI, e.g., an optical MMI, during parking. Additionally, it is also possible to use this second MMI to output distance information relating to the non-PLBO. As a result, a direct (acoustic) warning may be restricted to a potential collision with a temporary obstacle along the parking trajectory, while a complete representation of the vehicle environment continues to be output via an optical display. Alternatively, it is also possible to omit a PLBO in the optical representation as well. 
         [0011]    The output device may be developed in such a way that distance information relating to non-PLBOs is output to the second MMI, even if they do not constitute an obstacle along the parking trajectory. This makes it possible, for example, to still represent an object that does not lie on the current driving envelope and furthermore does not constitute a parking space delimitation, for instance in order to serve as orientation aid for the driver during the maneuvering. 
         [0012]    According to the exemplary embodiments and/or exemplary methods of the present invention, a driver assistance system which includes a parking assistance system as described above, is provided in addition. 
         [0013]    Additional aspects and advantages of the exemplary embodiments and/or exemplary methods of the present invention will now be described in greater detail with reference to the attached figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  shows functional components of a parking system according to the present invention, in the form of a schematic block diagram. 
           [0015]      FIG. 2  shows a manner of functioning of the system from  FIG. 1 , in the form of a flow chart. 
           [0016]      FIG. 3  shows an exemplary parking operation, in schematic form, to further illustrate the method of functioning of the system from  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 1  schematically illustrates the essential functional components of a parking assistance system  100  in the present invention, which parking assistance system  100 , for instance, may be part of an otherwise not further illustrated parking assistance system  102  in a passenger car. System  100  includes a data receiver device  104 , a calculation device  106 , a parking device  108 , as well as an output device  110 . 
         [0018]    A method of functioning of system  100  will be described in the following text with reference to the flow chart shown in  FIG. 2 . To elucidate matters, reference is also made to an exemplary parking operation outlined in  FIG. 3 . There, the trajectory of a vehicle (not shown) is illustrated, which includes a passing-by phase P 1  and a parking trajectory P 2 , P 3 , P 4 . 
         [0019]    In phase P 1 , the vehicle drives past a parking space  300 , which is delimited by parking-space delimiting objects (PLBOs)  302  and  304 . In this phase P 1  sensors  112  and  114  measure parking space  300 , that is to say, PLBOs  302  and  304  are detected. The two sensors  112  and  114  may be, for instance, an ultrasonic, a radar or an infrared sensor or a similar sensor, which are mounted on a left and right fender of the vehicle. 
         [0020]    In step  202  in  FIG. 2 , data receiver device  104  receives data from sensor system  112 ,  114  formed by sensors  112 ,  114 , the data relating to detected PLBO(s)  302  and  304 . 
         [0021]    The driver makes the decision to park in parking space  300 . System  100  now implements a parking assistance function that features an active control of a vehicle brake system in order to park in parking space  300 . In a step  204 , device  104  forwards the data from sensor system  112 ,  114  to calculation device  106 . Based on at least one of the two PLBOs  302  or  304 , device  106  calculates a parking trajectory, which is composed of a path  306  extending to stopping position S 1 , a path  308  from S 1  to a turning position U 1 , and a path  310  from U 1  to a final stopping position S 2 . 
         [0022]    In step  206 , calculation device  106  appropriately controls parking device  108  in order to implement parking along calculated parking trajectory  306 - 310 . Toward this end, parking device  108  may control a (schematically sketched) brake system  116  of the vehicle, for example. An important aspect is that the parking maneuver includes an active braking process when one of points S 1 , U 1  and S 2  is approached (i.e., in each phase P 2 , P 3 , and P 4 ). 
         [0023]    A schematically sketched object  312 , which has not been detected in phase P 1  because it is a mobile obstacle, for instance, is located in parking space  300 . Object  312  is detected only after phase P 1  has ended and it is detected as non-PLBO, since it is not located at the position of PLBOs  302  or  304  detected in phase P 1 , for example. Non-PLBO  312  constitutes an obstacle because the object is located within the travel path envelope, i.e., along calculated parking trajectory  306 - 310 . Calculation device  106  and/or parking device  108  are/is developed to perform the parking maneuver featuring phases P 2 -P 4  and the braking processes embedded therein, but not to implement any active brake control when detecting an obstacle such as obstacle  312 . 
         [0024]    In step  208 , output device  110  receives signals from the other devices  104 - 108  of parking assistance system  100  in order to output distance information about detected objects, such as objects  302 ,  304  and  312 , for instance, to two man-machine interfaces (MMIs)  118  and  120 . Device  118 , for instance, may be an acoustic output device such as a loudspeaker, and output device  120  may be an optical output device such as a display screen, for example. 
         [0025]    Output device  110  is set up to output only distance information in connection with detected non-PLBOs to MMI  118  during the parking operation (phase P 2  through P 4 ), but no distance information relating to PLBOs. In the event that the acoustic output includes the output of a distance warning as soon as a drop below a minimum distance occurs when approaching a non-PLBO, then there would be no acoustic output during phases P 2  and P 3  in the specific scenario of  FIG. 3 , but it would certainly occur during phase P 4  when approaching non-PLBO  312 . 
         [0026]    Output device  110  simultaneously outputs distance information about all detected objects to optical MMI  120 . As a result, no acoustic signal is output via MMI  118  during phase P 2 , because system  100  automatically brakes when stopping point S 1  is approached. An acoustic warning or distance information relating to PLBO  302  is therefore not required or would confuse the driver. However, to guide the driver, distances or positions or dimensions of PLBOs  302  and  304  are able to be displayed to the driver on display screen  120 . Even obstacle  312  may be displayed there, provided it has already been detected. 
         [0027]    There is also no output of distance information via acoustic MMI  118  during phase P 3 , because parking assistance system  100  carries out another automatic braking operation when turning point U 1  along trajectory  308  is approached, so that no driver intervention is required. However, to guide the driver, it is possible, as before, to output the entire vehicle environment to optical MMI  120 , including PLBOs  302  and  304  and possibly non-PLBO  312 . 
         [0028]    When the vehicle approaches non-PLBO  312  along trajectory  310  during phase P 4 , an acoustic output, i.e., distance warning, takes place in order to signal to the driver that he must perform active braking himself in this case to avoid a potential collision with obstacle  312 . In this situation, collision obstacle  312  may either continue to be displayed on display screen  120  (PLBOs  302  and  304  could be blanked out), or obstacle  312  may be contrasted with respect to PLBOs  302  and  304  in some other suitable manner. 
         [0029]    In the event that non-PLBO  312  disappears, i.e., is no longer detected, while the vehicle is approaching along trajectory  310 , no further distance output takes place via acoustic MMI  118 , since stopping point S 2  is reached by automatic braking interventions of parking assistance system  100 , regardless of whether or not an additional PLBO is situated behind point S 2 . 
         [0030]    The detection of an object as PLBO or non-PLBO may take place with the aid of ascertained distance values. Once again referring to phase P 2  in Figure P 2  by way of example, a conventional system would output a distance warning due to an approach of PLBO  302 , for instance when the vehicle is moving in the direction of point S 1  along trajectory  306 . In the system described here, a distance output to acoustic MMI  188 , for example, is able to be muted as long as an equivalent distance value with respect to PLBO  302  (taking a safety clearance into account) corresponds to the remaining stretch along path  306  still to be covered until stopping point S 1  in front of PLBO  302  has been reached. If PLBO  302  were to move during phase P 2  and, for instance, come overly close to stopping point S 1  or move beyond it, the equivalent distance value would be reduced and object  302  immediately be classified as a non-PLBO, i.e., no automatic braking would take place, but a distance warning be output via acoustic system  118 . 
         [0031]    With exemplary reference to phase P 4 , a distance warning via first MMI  188  because of a detected non-PLBO, for which no automatic braking intervention occurs, may also take place only after a predefined minimum distance to obstacle  312  along path  310  has been undershot. This minimum distance is selectable as a function of speed, for example, to ensure that the driver is able to stop the vehicle before a potential collision occurs. 
         [0032]    The present invention is not limited to these exemplary embodiments and the aspects emphasized therein, but instead may be modified in numerous ways known to one skilled in the art.