DE102015003964A1 - Method for the autonomous driving of a trajectory by a motor vehicle - Google Patents

Abstract

The invention relates to a method for autonomously driving a trajectory (14a, 14b) through a motor vehicle, comprising the following steps: a) recording a trajectory (14a) traveled by a motor vehicle (1), at least during tracing of the trajectory (14a) an operating parameter is determined and recorded as a function of the instantaneous position of the motor vehicle (1) along the trajectory (14a); b) partial autonomous or autonomous driving of the trajectory (14a) recorded in step a) by the motor vehicle (1), wherein the at least an operating parameter when trajectory traversing (14b) is determined again, wherein an obstacle (15) present on the trajectory (14b) is detected based on a comparison of the value of the at least one operating parameter with the value recorded in step a).

Description

The invention relates to a method for autonomously driving a trajectory through a motor vehicle and to a motor vehicle whose control device is set up / programmed to carry out this method. Finally, the invention relates to the use of such a method for the automated parking of a motor vehicle.

Modern motor vehicles are often equipped with a so-called parking assistance system, which supports the driver when parking the vehicle in a parking space. For this purpose, such an assistance system takes over the partial control of the vehicle during the parking process. The usual thing is that the parking assistant takes over the control of the hand steering wheel after its activation by the driver. By means of suitable sensors installed in the motor vehicle, for example in the form of radar sensors or camera systems, the desired parking space is measured and from the data thus obtained a trajectory is computed, which the vehicle must drive if it is to be maneuvered into the parking space. The parking assistant then takes over the control of the hand steering wheel, such that the calculated trajectory is traveled by the vehicle until the desired parking position is reached. The driver is to operate in this process only the accelerator pedal to gently accelerate the vehicle for the parking operation and decelerate again.

A problem with such parking assistants proves that they only allow driving relatively simple trajectories, which typically results when parking in a conventional parking space between two already parked vehicles.

For more complicated parking maneuvers and resulting trajectories, such as those required for automatic parking in a garage or the like, knows the prior art method in which the parking assistant "learns" to be traveled course of the trajectory. In such a process, the aforementioned sensor systems of the vehicle are used to record the course of the said trajectory while it is being driven by the vehicle. During the learning process, the vehicle is typically completely controlled by the driver. The "learned" trajectory is stored after completion of the recording and is thus available again when the motor vehicle is again - but this time not manually parked by the driver, but automatically by the parking assistant - at the same location. For positional adjustment of the instantaneous vehicle position relative to the learned trajectory, the data measured by the sensor systems when recording the trajectory are used and compared with current sensor data. In this way, it can be ensured that the motor vehicle is able to drive the learned trajectory automatically again with high spatial accuracy.

A disadvantage of such, advanced parking assistants, however, is that when the automatic "descendants" of the trajectory, any obstacle present on the trajectory for the first time is not detected by the parking assistant. In extreme cases, this can lead to the obstacle being overrun by the motor vehicle. In the event that such an obstacle is human, such rolling over by the motor vehicle to be parked would most likely involve serious or even fatal injuries.

Against this background, the DE 10 2009 001 183 A1 a method for detecting obstacles for a motor vehicle. Thus, a capacitive distance determining unit located in the area of the underbody is used to monitor the area underneath the vehicle. If there is an obstacle in this area, the associated capacity change can be detected by the distance determination unit.

It is therefore an object of the present invention to provide an improved method for automatic parking. Another object of the present invention is to provide a motor vehicle by means of which such a method can be carried out.

This object is solved by the subject matter of the independent patent claims. Preferred embodiments are subject of the dependent claims.

The basic idea of the invention is therefore to determine at least one operating parameter-for example, a torque acting on the wheels of the vehicle-as a function of the instantaneous position of the motor vehicle along the trajectory when recording a trajectory traveled by the motor vehicle. Such a position determination of the vehicle on the trajectory can take place with the aid of various sensor systems built into the vehicle, for example imaging sensors or radar sensors. For this purpose, the sensor data supplied by these sensor systems are recorded when driving on the first time as a function of the trajectory position and read out on renewed driving and evaluated so as to move the motor vehicle again along the trajectory. Alternatively, certain suitable for determining the trajectory Operating parameters such as vehicle speed and steering angle of the motor vehicle are recorded as a function of time and read out again.

If the trajectory learned by the motor vehicle in a first method step a), for example in the course of a partially or fully autonomous parking operation, is automatically re-entered in a second method step b), the value of the current position assigned to the trajectory is recorded when the trajectory is approached Operating parameters compared with the currently determined value at the same trajectory position. By means of such a comparison, when the trajectory is re-entered, it can be recognized as having an obstacle. This makes it possible to automatically respond to such an obstacle, such as by the vehicle is automatically stopped and reset. In this way it can be prevented that the obstacle is overrun by the motor vehicle. If the obstacle is a human, severe or even fatal injuries can be avoided. In the event that the obstacle is a non-human object, damage to the object and to the motor vehicle can be minimized.

As a result, the inventive method presented here realizes a partially or even fully autonomous parking operation with integrated obstacle detection, based on a learned trajectory of a motor vehicle reproducing the parking path. In the present case, the term "partially autonomous" encompasses all parking operations in which at least a portion of the control processes made by the driver of the vehicle in a conventional manner - to be mentioned, for example, the actuation of the steering wheel - is taken over by the control unit of the motor vehicle. The driver thus only has to operate the throttle and brake pedal to control the vehicle speed during parking. In the fully autonomous parking operation, however, the necessary to move the vehicle along the learned trajectory control operations are performed entirely by the controller. In this case, it is not necessary for the driver to sit at the wheel of the vehicle. In this case, such a fully autonomous parking operation can be started by the driver outside the vehicle, for example using a remote control communicating with the control unit.

The term "operating parameters" in the present case includes all parameters which are suitable for the description of the current operating state of the motor vehicle.

In a preferred embodiment, an obstacle is detected in step b) if the value of the at least one operating parameter determined in step b) deviates from the value recorded in step a). This can be achieved, for example, by a simple difference formation between the value of the at least one operating parameter determined in step a) and the value determined in step b). It is understood that for such a difference in each case values must be used, which are assigned to the same vehicle position on the learned trajectory. If the difference formed in this way exceeds a predetermined threshold value, this can be interpreted as the presence of an obstacle on the trajectory used in step b).

In an advantageous development of the method according to the invention, it is advisable, as already mentioned, to automatically stop the motor vehicle in an additional method step c) if an obstacle has been detected in step b). Such an automatic stop process can be initiated by the control unit of the motor vehicle.

In order to further reduce the risk of injury to a human obstacle, it can be provided in a further advantageous development of the method to reset the motor vehicle along the trajectory, in particular by a predetermined path length, after it has been stopped in step c) in a further additional step d) , Ideally, a mechanical contact of the motor vehicle with the obstacle can be almost avoided in this way.

In a preferred embodiment, the at least one operating parameter may be a torque acting on a vehicle wheel of the motor vehicle. For measuring the torque, a conventional, communicating with the control unit of the motor vehicle torque sensor can be used as it is installed as standard in modern vehicles. In an advantageous development, it is conceivable to carry out such a torque measurement not only on the basis of a single sensor assigned to a specific wheel of the motor vehicle, but to use a plurality of torque sensors associated with different wheels of the motor vehicle in combination.

In another preferred embodiment, it is proposed to use not only a single operating parameter, but at least two different operating parameters for obstacle detection. According to this embodiment, at least two operating parameters must therefore be recorded in step a) and compared in each case with the currently determined value in step b). Based on one Such a comparison can then detect the obstacle present on the trajectory. The concrete implementation of such a comparison opens up a variety of options for the person skilled in the art. It is conceivable, for example, to compare the at least two operating parameters independently of one another and to evaluate based on such individual comparisons whether an obstacle exists or not. It is also conceivable to weight individual comparisons to determine whether an obstacle exists or not. A comparison of a combination of individual parameters is conceivable.

The invention also relates to a motor vehicle with a control unit and with at least one sensor, by means of which the value of the at least one operating parameter can be determined and transmitted to the control unit. According to the invention, the control unit is set up / programmed to carry out the method presented above.

To detect the obstacle present on the trajectory distance sensor can be installed, which is directed downward. Such sensor may be ultrasonic, radar or other distance measuring sensor. Fitting locations can be behind the front bumper or behind the rear bumper. The sensor device is protected against dirt and moisture when not in use by a protection device. In addition, this sensor device for distance measurement may include self-cleaning by spraying device.

Finally, the invention relates to the use of the previously explained method for the automated parking of a motor vehicle.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

It show, each schematically:

1 an example of a motor vehicle according to the invention,

2 a rough schematic flow diagram of the method according to the invention,

3 a sketchy representation of a Einpark situation in which the inventive method can be used.

1 Illustrates in a schematic representation and in a side view an example of a motor vehicle according to the invention 1 , This includes a control unit 2 , which for the partially or fully autonomous control of the motor vehicle 1 is set up, which means that from the control unit 2 In a limited framework, the steering and the acceleration and deceleration of the motor vehicle can be adopted without driver intervention. In the side view of 1 are a front wheel 3a and a rear wheel 3b recognizable, each with a brake unit 4a . 4b are equipped, by means of which the two wheels 3a . 3b can be slowed down. The two brake units 4a . 4b stand with the control unit 2 in communication connection. This allows a control of the two brake units 4a . 4b through the control unit 2 so that this can initiate an automatic braking intervention if necessary. At each of the two wheels 3a . 3b is a torque sensor 5a respectively. 5b attached, which on his assigned wheel 3a respectively. 3b acting torque - this is an operating parameter in the above sense - is able to measure and the measured torque via a suitable communication link to the control unit 2 transmitted. Furthermore, the motor vehicle comprises an optical sensor system 6 , for example in the form of a camera, as well as a radar system 7 , which both the apron 8th of the motor vehicle to monitor optically or by means of radar beams.

To carry out the in 2 in the form of a flowchart illustrated inventive method in the control unit 2 becomes the of the motor vehicle 1 recorded trajectory recorded. While recording the trajectory - this can be done by recording the from the sensor systems 7 . 8th supplied sensor data in the control unit 2 happen - is also at least one operating parameter in the form of the torque sensor 5a . 5b measured torque as a function of the current position of the motor vehicle 1 determined and recorded along the trajectory. This happens in a first method step a).

Thereafter, in a second method step b), a partially autonomous or autonomous driving of the trajectory recorded in step a) takes place 14a by the motor vehicle 1 , For this purpose, the sensor data recorded in step a) are used to move the vehicle along the desired trajectory 14a to move. This procedure is familiar to the person skilled in the art as so-called "self-localization".

Alternatively, in step a) for recording the trajectory 14a also the trajectory 14a clearly defining operating parameters such as the vehicle speed and the current steering angle of the vehicle 1 recorded as a function of time. To re-enter the trajectory 14a as a trajectory 14b in step b), these data in step b) from the control unit 2 used and the motor vehicle 1 controlled accordingly.

It becomes one on the trajectory 14b any obstacle (see obstacle 15 in 3 ) based on a comparison of the torque sensor 5a . 5b measured value of the torque detected with the value recorded in step a). Such a comparison becomes when driving the trajectory 14b in step b) is carried out iteratively, wherein the value of the torque measured at a certain trajectory position is compared with the value measured in step a) at the same trajectory position. Such a scenario exemplifies the 3 , which in a rough schematic representation of the motor vehicle 1 when parking in a garage 10 shows which, starting from a road 11 - via an access road 12 can be reached with a right angle course. The exemplary method explained here by way of example can therefore be used to park the motor vehicle 1 be used.

The trajectory used in step a) and thus "learned" is in 3 through the dashed arrow 14a played. It runs from the street 11 over the access road 12 in the interior of the garage 10 into it. The trajectory 14a is doing by the driver of the vehicle 1 during the driving or learning according to step a) determined by appropriate control maneuvers.

The in the course of step b) from the motor vehicle 1 then partially or fully autonomously traded trajectory 14b runs up to an existing obstacle 15 in the area of the access road 12 identical to the previously recorded trajectory 14a ie, the trajectory learned in step a) is taken from the vehicle 1 in step b) to the obstacle 15 - It can be about a person or an object - identical.

Because the obstacle 15 when recording the trajectory 14a according to step a), the value of the torque measured in step b) at this trajectory position deviates from the value recorded in step a) as soon as the motor vehicle 1 the obstacle 15 when driving on the access road 12 touched. This can be determined, for example, by subtraction of the torque values to be compared and comparison with a predetermined threshold value. If said difference exceeds the predetermined threshold value, then an obstacle becomes 15 recognized. In this case, the motor vehicle 1 in a third method step c) from the control unit 2 by means of a braking intervention in the brake units 4a . 4b be stopped automatically. This will prevent the obstacle 15 from the motor vehicle 1 is rolled over. If the obstacle is a human, severe or even fatal injuries can be avoided. In the event that it is at the obstacle 15 is a non-human object, so damage to the object and the vehicle 1 be largely or even completely excluded.

To the risk of injury to a human obstacle 15 can further reduce the motor vehicle 1 in a further, optional step d) of the method presented here along the trajectory 14b be reset in the opposite direction to the original direction of movement. The term "reset" is in this case a moving of the motor vehicle 1 by a predetermined path along the trajectory 14b , but in the opposite direction to the original direction of movement of the vehicle 1 understood when parking. Such a reset is in 3 by an arrow with the reference numeral 14c indicated.

In a variant of the example not shown in the figures, it is also conceivable to use not only a single operating parameter, for example in the form of said torque, but at least two different operating parameters. As an additional operating parameter, for example, comes from the drive system of the motor vehicle 1 generated drive torque when driving on the trajectories 14a . 14b ,

In such a variant, all operating parameters to be used for obstacle detection must be recorded in step a) of the method. These operating parameters are then each compared with the previously recorded value when driving in accordance with step b). Based on this comparison, one can then rely on the trajectory 14b existing obstacle are detected.

For the concrete implementation of such a comparison on the basis of several operating parameters open to the skilled person various options. It is conceivable, for example, to compare the at least two operating parameters independently of one another and to evaluate based on such individual comparisons whether an obstacle exists or not.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009001183 A1 [0006]

Claims (7)

Method for the autonomous driving of a trajectory ( 14a . 14b ) by a motor vehicle ( 1 ), comprising the following steps: a) recording one of a motor vehicle ( 1 ) trajectory ( 14a ), during the trajectory recording ( 14a ) at least one operating parameter as a function of the current position of the motor vehicle ( 1 ) along the trajectory ( 14a ) is determined and recorded, b) partial autonomous or autonomous driving of the trajectory recorded in step a) ( 14a ) by the motor vehicle ( 1 ), wherein the at least one operating parameter when driving the trajectory ( 14b ) is again determined, one on the trajectory ( 14b ) existing obstacle ( 15 ) is detected based on a comparison of the value of the at least one operating parameter when driving in accordance with step b) with the value recorded in step a). Method according to claim 1, characterized in that an obstacle ( 15 ) is detected when the value of the at least one operating parameter determined in step b) deviates from the value recorded in step a). A method according to claim 1 or 2, characterized in that the method comprises the following additional step c), if in step b) an obstacle ( 15 ) was detected: c) stopping the motor vehicle ( 1 ). Method according to one of the preceding claims, characterized in that the at least one operating parameter ein on a vehicle wheel ( 3a . 3b ) of the motor vehicle ( 1 ) acting torque is. Method according to one of the preceding claims, characterized in that in step a) at least two operating parameters are recorded and in step b) the at least two operating parameters recorded in step a) are respectively compared with the currently determined values, based on this comparison on the trajectory ( 14a . 14b ) existing obstacle ( 15 ) is recognized. Motor vehicle ( 1 ), - with a control unit ( 2 ), - with at least one sensor ( 5a . 5b ), by means of which an instantaneous value of the at least one operating parameter can be determined and sent to the control unit ( 2 ) is transferable, - wherein the control unit ( 2 ) is set up / programmed for carrying out the method according to one of the preceding claims. Use of the method according to one of claims 1 to 5 for the automated parking of a motor vehicle ( 1 ).

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