DE102017122426A1 - Control with specification of a speed profile - Google Patents

Abstract

The invention relates to a method for maneuvering a vehicle (10) with specification of a speed profile (40) along a trajectory (30), comprising the steps of determining the trajectory (30) for moving the vehicle (10), subdividing the trajectory (30) into a plurality of sections (42, 44, 46), determining a maximum speed for each section (42, 44, 46) of the trajectory (30) to form the velocity profile (40), maneuvering the vehicle (10) along the trajectory (30), comprising determining a desired speed change taking into account the speed profile (40), the method comprising an additional step of establishing a prediction of a position of the vehicle (10) along the trajectory (30) and a speed of the vehicle (10), and determining a Set speed change, taking into account the speed profile (40) determining the desired speed change under zus additional consideration of the prediction of the position of the vehicle (10) along the trajectory (30) and the speed of the vehicle (10). The invention also relates to a driver assistance system (12) for a vehicle (10), in particular as a parking assistance system (12) for carrying out an autonomous parking operation for the vehicle (10), wherein the driver assistance system (12) is designed to carry out the above method. The invention further relates to a vehicle (10) having an above driver assistance system (12).

Description

The present invention relates to a method for maneuvering a vehicle with specification of a velocity profile along a trajectory, comprising the steps of determining the trajectory for moving the vehicle, subdividing the trajectory into a plurality of sections, determining a maximum speed for each section of the trajectory for forming the velocity profile, Maneuvering the vehicle along the trajectory, comprising determining a desired speed change taking into account the speed profile.

The present invention also relates to a driver assistance system for a vehicle, in particular as a parking assistance system for carrying out an autonomous parking operation for the vehicle, wherein the driver assistance system is designed to carry out the above method.

Furthermore, the present invention relates to a vehicle having an above driver assistance system.

Various methods are known in the art for assisting a driver of a vehicle in various driving situations. Such methods are usually provided with a driver assistance system for such vehicles.

Such methods for maneuvering a vehicle and corresponding driver assistance systems are known for a very wide variety of tasks, for example for parking the vehicle along a trajectory in a parking position. In this case, parking positions can be detected, for example with the aid of environmental sensors. In addition, the environment can also be detected. Based on this information, a trajectory can be determined from a current position of the vehicle for parking the vehicle in the parking space.

The parking position with an associated trajectory can also be learned by the vehicle, for example by carrying out a corresponding parking operation with the vehicle and storing a trajectory used thereby. Environmental information captures and provides environmental information.

It is known, for example, that the vehicle is parked semi-autonomously in the parking position with the aid of the driver assistance system and also leaves the parking position again. In this case, the driver assistance system may, for example, take over an intervention in the steering, i. a transverse guide of the vehicle, and the driver of the vehicle operates accelerator pedal and brake to control longitudinal movement of the vehicle, i. to control a longitudinal guidance of the vehicle.

In addition, methods and driver assistance systems are known in which the vehicle is autonomously or fully autonomously parked in the parking position. In this case, the driver assistance system of the vehicle takes over the longitudinal guidance during the parking process in addition to the transverse guidance. This means that the driver assistance system in addition to an intervention in the steering also performs an intervention in the drive and / or the brake system of the vehicle. Among other things, it is known that, based on the determined trajectory for parking the motor vehicle in the parking space, a course of the steering angle for the movement of the motor vehicle along the trajectory is predicted. In addition, a velocity profile for the movement of the motor vehicle along the trajectory can be determined.

The speed profile can be created by dividing the trajectory into several sections. This subdivision can be done, for example, depending on the course of the steering angle. Based on this, a maximum speed can be specified for each section, from which the overall speed profile for the trajectory can be determined in combination. Additionally, for transitions between successive sections, a speed change between the maximum speeds of the adjacent sections may be specified.

In this context is from the DE 10 2004 054 437 B4 a method for automatically controlling and / or regulating a movement of a vehicle during a parking operation known. The method for automatically controlling and / or regulating a movement of a vehicle during a parking operation is carried out by means of a parking system. The parking system comprises at least one control and / or regulating device. The method comprises the following steps: determining a target distance to be followed by the vehicle during a parking operation; Calculating by means of the control and / or regulating device of at least one desired value of a longitudinal movement parameter as a function of at least one transverse movement parameter and a position of the vehicle along the desired distance, wherein the longitudinal movement parameter is a longitudinal velocity v of the vehicle and the transverse motion parameter is a steering angle of the vehicle and / or describes a steering angle of a means for influencing the steering angle of the vehicle; and fully automatic Controlling and / or regulating the longitudinal movement parameter and the transverse movement parameter by means of the control and / or regulating device, wherein at least temporarily during the parking process at least one desired value of a time derivative of the transverse movement parameter in dependence on the longitudinal movement parameter and / or the position of the vehicle along the desired distance is calculated.

In addition, from the DE 10 2014 220 300 A1 a shunting assistant and a Rangierassistenzverfahren for a motor vehicle. A method for monitoring the distance of a motor vehicle to an obstacle comprises the following steps: predicting a first trajectory along which the motor vehicle will move; Detecting an obstacle; Determining the predicted distance of the motor vehicle to the obstacle when the motor vehicle moves along the first trajectory; Determining a maximum permissible passing speed as a function of the predicted distance with which the motor vehicle may pass the obstacle along the first trajectory; Determining a predicted actual speed at which the motor vehicle has passed the obstacle along the first trajectory; If the predicted actual speed exceeds the maximum allowable pass speed, decelerating the motor vehicle with a delay selected to reduce the speed to the maximum pass speed when the motor vehicle passes the obstacle along the first trajectory.

Based on the above-mentioned prior art, the invention is therefore based on the object to provide a method for maneuvering a vehicle with specification of a speed profile along a trajectory, a driver assistance system for a vehicle for performing this method and a vehicle with such a driver assistance system, the one allow reliable longitudinal guidance of a vehicle according to a certain speed profile and to reduce deviations of an actual speed of the vehicle from the speed profile as well as swinging the actual speed or beyond.

The object is achieved by the features of the independent claims. Advantageous embodiments of the invention are specified in the subclaims.

According to the invention there is thus provided a method for maneuvering a vehicle with specifying a velocity profile along a trajectory, comprising the steps of determining the trajectory for moving the vehicle, subdividing the trajectory into a plurality of sections, determining a maximum speed for each section of the trajectory for forming the velocity profile, Maneuvering the vehicle along the trajectory, comprising determining a desired speed change taking into account the speed profile, the method comprising an additional step of establishing a prediction of a position of the vehicle along the trajectory and a speed of the vehicle, and determining a desired speed change taking into account the speed profile determining the desired speed change with additional consideration of the prediction of the position of the vehicle along the track ctorie and the speed of the vehicle.

According to the invention, a driver assistance system for a vehicle is also specified, in particular as a parking assistance system for carrying out an autonomous parking operation for the vehicle, wherein the driver assistance system is designed to carry out the above method.

Further, according to the invention, a vehicle is specified with an above driver assistance system.

The basic idea of the present invention is therefore to avoid errors in the implementation of the speed profile in the longitudinal control of the vehicle by the longitudinal control by the prognosis, i. a predictive determination of the position of the vehicle, a tolerance to a real behavior of the vehicle has. When implementing the target acceleration, there may be significant delays and errors due to the vehicle. Foresight thus compensates for the inertia of the longitudinal guidance of the vehicle, for example. Also, the forecasting system makes the system more tolerant of errors in implementing the target acceleration. Moreover, the delays and errors are not only dependent on a vehicle type, i. For example, a manufacturer and a model, but also from each individual vehicle. In addition, environmental factors such as rain or snow can lead to delays and errors. As a result, the delays can only be determined in advance to a very limited extent and can already be taken into account in advance when implementing the control. In general, errors can only be taken into account in advance in the longitudinal control.

In the longitudinal control of the vehicle, it is also important that the vehicle complies with limits in acceleration and acceleration change, for example, to avoid a noticeable "jolt" while driving. This can be reliably implemented with the prognosis and the longitudinal control based thereon.

The maneuvering of the vehicle here essentially relates to the longitudinal control of the vehicle, ie acceleration and deceleration of the vehicle. However, in addition, a lateral control can take place, ie the vehicle is steered autonomously.

The trajectory is a predetermined distance, which is covered by the vehicle with the corresponding driver assistance system, that is, a route which usually comprises a short total driving distance of less than one kilometer in current driver assistance systems. In principle, however, the trajectory can also cover a longer distance of more than one kilometer. The trajectory can be determined by the driver assistance system itself or learned, for example. Also, the trajectory can be transmitted via a server to the driver assistance system.

The subdivision of the trajectory into a plurality of sections relates to a subdivision into a section with a constant maximum speed, for example straight-ahead driving sections or cornering sections. Based on this, the maximum speed can be determined for each section. The maximum speed is usually less for cornering than for straight ahead driving.

In order to maneuver the vehicle along the trajectory, the desired speed change is determined based on the velocity profile, particularly at the transition of one segment to another. A difference of the actual speed to the target speed is determined, and based on a difference, the target speed change is determined.

Creating a prediction of a position of the vehicle along the trajectory and a speed of the vehicle involves a look ahead at which point the vehicle will be at a future time. Accordingly, a setpoint speed at the time of the prediction can be determined according to the speed profile and additionally used for determining a current setpoint speed change.

In an advantageous embodiment of the invention, the step of generating a prediction of a position of the vehicle along the trajectory and a speed of the vehicle comprises establishing the prognosis based on a current position, a current speed and / or a current desired speed change. Based on one or more of the position, current speed, and current desired speed change parameters, the future position of the vehicle may be determined according to the speed profile, for example. From this, in particular a future target speed can be determined with a high degree of safety.

In an advantageous embodiment of the invention, the step of establishing a prediction of a position of the vehicle along the trajectory and a speed of the vehicle comprises creating the prognosis taking into account a delay time of the vehicle for changing the speed. The delay time corresponds to a conventional inertia of the vehicle to implement a desired speed change. This may vary depending on the model, the vehicle used, or even environmental conditions. Preferably, the delay time is chosen to be large enough to cover these factors. Preferably, the delay time specifies a value that is below a time for the forecast. Thus, the prognosis reaches beyond the period of the possible delay time, whereby a corresponding control can be reliably and stably implemented. Thus, the look-ahead is chosen to be at least slightly larger than the delay time in order to be able to compensate for typically occurring delays.

In an advantageous embodiment of the invention, taking into account a delay time of the vehicle for changing the speed, the step of generating prognosis comprises establishing the prognosis, taking into account a delay time for accelerating the vehicle and a delay time independent of it for decelerating the vehicle. The delay time may be different in practice for accelerating and decelerating the vehicle. These different delay times can, for example, be taken into account individually for acceleration and deceleration by the prognosis being carried out differently depending on a determined acceleration or deceleration. Alternatively, the larger of the two delay times can be used as the default value for all driving situations. In each case the prognosis reaches further than the corresponding delay time.

In an advantageous embodiment of the invention, the step of creating a prognosis, taking into account a delay time of the vehicle for changing the speed, comprises creating the prognosis taking into account a constant deceleration time of the vehicle. The delay time is thus set independently of ambient conditions, vehicle, direction of travel, intended acceleration or deceleration, or the like, so that the prognosis always goes beyond this delay time. This enables a simple implementation of the prognosis and the longitudinal control based on it.

In an advantageous embodiment of the invention, the step of generating the prognosis taking into account a delay time of the vehicle for changing the speed comprises a parameterization of the delay time. By parameterizing, the delay time may be parameterized, for example, depending on at least one condition among a group of conditions including environmental conditions, vehicle, direction of travel, intended acceleration or deceleration, or the like, the prognosis always exceeding the parameterized delay time. This allows a particularly reliable implementation of the prognosis and the longitudinal control based thereon. In simulation and practice, it has been found that with a parameterized delay time also with additional possible errors of a subsequent control to implement the desired speed change, i. The vehicle is sometimes a greater acceleration / deceleration than required, and sometimes a lower, very good results can be achieved.

In an advantageous embodiment of the invention, the driver assistance system has an interface for connection to an acceleration interface of the vehicle. In an advantageous embodiment of the invention, the vehicle has an acceleration interface for connecting the vehicle to an interface of the driver assistance system. Such an acceleration interface is nowadays being made available in an increasing number of vehicles in order to enable an implementation of various driver assistance systems. The interface is designed to transfer commands for both positive and negative acceleration. Thus, a longitudinal control of the vehicle with the driver assistance system can be realized in a simple manner via the interface.

The invention will be explained in more detail with reference to the accompanying drawings with reference to preferred embodiments. The illustrated features may represent an aspect of the invention both individually and in combination. Features of various embodiments are transferable from one embodiment to another.

• 1 eine schematische Darstellung eines Fahrzeugs gemäß einer ersten, bevorzugten Ausführungsform mit einem Fahrerassistenzsystem zum automatischen Parken des Fahrzeugs in einer Draufsicht,
• 2 eine Darstellung des Fahrzeugs aus 1 in einem Umgebungsbereich mit einer Trajektorie zum automatischen Parken des Fahrzeugs in einer Parkposition als Draufsicht,
• 3 ein Ablaufdiagramm zum Manövrieren des Fahrzeugs der ersten Ausführungsform mit Vorgabe eines Geschwindigkeitsprofils entlang der Trajektorie,
• 4 ein Diagramm eines beispielhaften ersten Verlaufs eines Geschwindigkeitsprofils zum Fahren entlang der Trajektorie und eine ermittelte Istgeschwindigkeit,
• 5 ein Diagramm eines beispielhaften zweiten Verlaufs eines Geschwindigkeitsprofils zum Fahren entlang der Trajektorie und eine ermittelte Istgeschwindigkeit, und
• 6 ein Diagramm eines beispielhaften dritten Verlaufs eines Geschwindigkeitsprofils zum Fahren entlang der Trajektorie und eine ermittelte Istgeschwindigkeit.

It shows

• 1 1 is a schematic representation of a vehicle according to a first preferred embodiment with a driver assistance system for automatic parking of the vehicle in a plan view;
• 2 a representation of the vehicle 1 in a surrounding area with a trajectory for automatic parking of the vehicle in a parking position as plan view,
• 3 a flowchart for maneuvering the vehicle of the first embodiment with specification of a velocity profile along the trajectory,
• 4 3 is a diagram of an exemplary first course of a speed profile for driving along the trajectory and a determined actual speed;
• 5 a diagram of an exemplary second course of a speed profile for driving along the trajectory and a determined actual speed, and
• 6 a diagram of an exemplary third course of a speed profile for driving along the trajectory and a determined actual speed.

The 1 shows a vehicle 10 according to a first preferred embodiment of the present invention in a plan view.

The vehicle 10 includes a driver assistance system 12 , The driver assistance system 12 in turn comprises a control device 14 which, for example, an electronic control unit (ECU - Electronic Control Unit) of the vehicle 10 includes. In addition, the driver assistance system includes 12 eight environmental sensors 16 , which are each formed as ultrasonic sensors. There are four environmental sensors 16 at a front area 20 of the vehicle 10 and four environmental sensors 16 at a stern area 22 of the vehicle 10 arranged. The environmental sensors 16 are trained objects 24 in a surrounding area 26 of the vehicle 10 capture. The environmental sensors 16 serve in particular to a relative position between objects 24 and the vehicle 10 to determine. The environmental sensors 16 are in this embodiment at corresponding through holes in bumpers of the vehicle 10 arranged. In an alternative embodiment, the environmental sensors are 16 hidden behind the bumpers.

The driver assistance system 12 has an interface not explicitly shown here for connection to an acceleration interface, not shown, of the vehicle 10 on. The interface is for transmitting commands for positive as well as negative acceleration for longitudinal control of the vehicle 10 with the driver assistance system 12 executed.

The driver assistance system 12 is in this embodiment as a parking assistance system for performing an autonomous parking operation for the vehicle 10 according to a trajectory 30 executed. The trajectory 30 is a learned trajectory 30 in this embodiment. The trajectory 30 is a given distance from the vehicle 30 with the driver assistance system 12 is to be covered.

The trajectory 30 is exemplary in 2 shown. With the help of the driver assistance system 12 should the vehicle 10 autonomous in a parking position 32 parked. In this embodiment, the trajectory is 30 a learned trajectory 30 that the vehicle 10 by a controller with the controller 12 departs. This will be the surrounding area 26 continuously with the environmental sensors 16 of the vehicle 10 supervised. One of the environmental sensors 16 monitored area 34 is for the front area 20 and the rear area 22 of the vehicle 10 illustrated by way of example.

Below is an in 3 illustrated method for maneuvering the vehicle 10 with specification of a speed profile 40 along the trajectory 30 described. The procedure is with the vehicle 10 and the driver assistance system 12 of the first embodiment.

The procedure begins in step S100 with a determination of the trajectory 30 to move the vehicle 10 , In the present case, the trajectory 30 from a memory for learned trajectories 30 selected.

In step S110 becomes the trajectory 30 into a plurality of sections 42 . 44 . 46 divided. A first section 42 the trajectory 30 is executed as a curve, a second section 44 the trajectory 30 is designed as a straight, which can be driven at an increased speed, and a third section 46 the trajectory 30 is designed as a straight that can be driven at a low speed to the vehicle 10 in the parking position 32 to stop

In step S120 becomes a maximum speed for each section 42 . 44 . 46 the trajectory 30 for the formation of the velocity profile 40 certainly. The trajectory becomes corresponding 30 in sections 42 . 44 . 46 divided with a constant maximum speed. This will be for each section 42 . 44 . 46 determines the respective maximum speed, as already stated above. The maximum speed is for cornering in the first section 42 less than for straight ahead in the second section 44 , and for the straight ahead of the third section 46 before reaching the parking position 32 lower than for the straight ahead in the second section 44 ,

According to steps S130 becomes the vehicle 10 along the trajectory 30 maneuvered. Maneuvering the vehicle 10 here concerns lateral control of the vehicle 10 ie the vehicle 10 is autonomously steered, together with a longitudinal control of the vehicle 10 ie accelerating and decelerating the vehicle 10 , Here, however, only the longitudinal control of the vehicle 10 to be viewed as.

When maneuvering the vehicle 10 along the trajectory 30 each one is a forecast of a position of the vehicle 10 along the trajectory 10 and a speed of the vehicle 10 created. There is a preview, at which point the trajectory and thus the velocity profile 40 the vehicle 10 located at a future time. The forecast is generated based on a current position, a current speed and a respective current set speed change.

In the process, the prognosis takes into account a delay time of the vehicle 10 created to change the speed. The delay time corresponds to a usual inertia of the vehicle 10 to implement a desired speed change. The delay time indicates a value which is below a time for the prognosis, so that the prognosis extends beyond the period of the delay time.

The delay time is used as a constant delay time of the vehicle 10 , The delay time can be parameterized here. The parameterization takes place here, for example, depending on at least one condition from a group of conditions including environmental conditions, vehicle 10 , Direction of travel, intended acceleration or deceleration. The prognosis always goes beyond the parameterized delay time.

Based on the forecast, a target speed at the time of the prediction becomes the speed profile 40 determined and additionally used to determine a current desired speed change.

The desired speed change is based on the speed profile 40 and with additional consideration of the forecast of the position of the vehicle 10 along the trajectory 30 and the speed of the vehicle 10 certainly. The desired speed change is especially at the transition between two sections 42 . 44 . 46 relevant, since here the Speed according to speed profile 40 changes. However, the setpoint speed change is to be determined continuously, since there is always a difference between an actual speed 48 may be present at the desired speed. The desired speed change is thus based on a difference between the desired speed and the actual speed 48 , where additionally the prognosis is considered.

Implementations of the longitudinal control are in the 4 to 6 each showing a course of the velocity profile 40 and the determined actual speed of the vehicle 10 while driving along the trajectory 30 demonstrate.

As in 4 is shown, the velocity profile 40 complied with the longitudinal control. At time t = 0 and at time t1, there is a change in the desired speed according to the speed profile 40 , The change in the setpoint speed is achieved by a respective continuous change of the actual speed. This corresponds to an ideal longitudinal control of the vehicle 10 via its acceleration interface, which is hardly achievable in practice due to the delay time and errors in the speed control.

5 shows the speed profile 40 in the longitudinal control, wherein the longitudinal control is created with a prognosis below the delay time. At time t = 0 and at time t2, there is a change in the desired speed according to the speed profile 40 , The actual speed oscillates 48 in each case around the set speed according to the speed profile 40 , There is no stable actual speed 48 one. Such a longitudinal control of the vehicle 10 is not desirable because an at least approximately constant actual speed 48 is desirable.

6 shows the speed profile 40 in the longitudinal control, wherein the longitudinal control is created with a forecast, ie a forecast, above the delay time. At time t = 0 and at time t3, a change in the setpoint speed takes place in each case according to the speed profile 40 , At the time of changing the set speed, the actual speed oscillates 48 first by the respective set speed according to the speed profile 40 , However, the vibration stops and it turns an approximately stable actual speed 48 one. Such a longitudinal control can in practice with the described method and the described driver assistance system 12 be achieved.

LIST OF REFERENCE NUMBERS

10

vehicle

12

Driver assistance system, parking assistance system

14

control device

16

Ambient sensor, ultrasonic sensor

20

front area

22

rear area

24

object

26

surrounding area

30

trajectory

32

parking position

34

monitored area

40

velocity profile

42

first section

44

second part

46

third section

48

Is speed

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 102004054437 B4 [0010]
• DE 102014220300 A1 [0011]

Claims (10)

Method for maneuvering a vehicle (10) with predetermination of a speed profile (40) along a trajectory (30), comprising the steps of determining the trajectory (30) for moving the vehicle (10), subdividing the trajectory (30) into a plurality of sections ( 42, 44, 46), determining a maximum velocity for each section (42, 44, 46) of the trajectory (30) to form the velocity profile (40), maneuvering the vehicle (10) along the trajectory (30), including determining a Target speed change taking into account the speed profile (40), characterized in that the method comprises an additional step of establishing a prediction of a position of the vehicle (10) along the trajectory (30) and a speed of the vehicle (10), and determining a desired speed change taking into account the speed profile (40), a determination of the desired speed change zusät Considering the prognosis of the position of the vehicle (10) along the trajectory (30) and the speed of the vehicle (10). Method according to Claim 1 characterized in that the step of generating a prediction of a position of the vehicle (10) along the trajectory (30) and a speed of the vehicle (10) comprises generating the prediction based on a current position, a current speed, and / or a current one Target speed change includes. Method according to one of the preceding Claims 1 or 2 characterized in that the step of establishing a prediction of a position of the vehicle (10) along the trajectory (30) and a speed of the vehicle (10) comprises compiling the prognosis taking into account a deceleration time of the vehicle (10) to change the speed , Method according to Claim 3 characterized in that the step of generating a prognosis taking into account a deceleration time of the vehicle (10) for changing the speed, compiling the prognosis taking into account a deceleration time for accelerating the vehicle (10) and a deceleration time independent therefrom for decelerating the vehicle (10) includes. Method according to one of the preceding Claims 3 or 4 characterized in that the step of generating a prognosis taking into account a delay time of the vehicle (10) for changing the speed comprises generating the prognosis taking into account a constant deceleration time of the vehicle (10). Method according to one of the preceding Claims 3 to 5 characterized in that the step of generating the prognosis taking into account a delay time of the vehicle (10) for changing the speed includes parameterizing the delay time. Driver assistance system (12) for a vehicle (10), in particular as a parking assistance system (12) for performing an autonomous parking operation for the vehicle (10), wherein the driver assistance system (12) is designed to carry out the method according to one of the preceding claims. Driver assistance system (12) after Claim 7 , characterized in that the driver assistance system (12) has an interface for connection to an acceleration interface of the vehicle (10). Vehicle (10) with a driver assistance system (12) according to one of the preceding Claims 7 or 8th , Vehicle (10) to Claim 9 , characterized in that the vehicle (10) has an acceleration interface for connecting the vehicle (10) to an interface of the driver assistance system (12).

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