DE102018209866A1 - Parking assistance system for automated parking with an advantageous transfer of vehicle guidance to the driver - Google Patents

Abstract

One aspect of the invention relates to a parking assistance system for a motor vehicle for automated parking with automated longitudinal and lateral guidance from a parking space. The parking assistance system is set up to actively keep the vehicle at a standstill after a transfer position for transferring the vehicle guidance to the driver has been reached. To take over vehicle control, the parking assistance system expects the driver to actuate the accelerator pedal. When the driver's operation of the accelerator pedal is detected, the vehicle stops at a standstill.

Description

The invention relates to a parking assistance system for a motor vehicle for automated parking with automated lateral and longitudinal guidance, for example from a longitudinal parking space parallel to the lane or a transverse parking space transverse to the lane.

In parking assistance systems with only automated lateral guidance, the system steers the motor vehicle during the parking process. The driver must take over the longitudinal guidance by accelerating and braking accordingly. In the case of parking assistance systems with automated lateral guidance and automated longitudinal guidance, the task of longitudinal guidance is also partially or completely carried out by the parking assistance system, depending on the degree of automation of the longitudinal guidance. In parking assistance systems with automated lateral guidance and automated longitudinal guidance, the steering, the brakes, the vehicle drive and the direction of travel (forwards or backwards) are generally controlled by the parking assistance system. In such parking assistance systems, the driver has the option, for example, of parking the vehicle independently by actuating an operating element in the vehicle cockpit, for example a button; it can be provided that the control element must continue to be actuated during the parking maneuver.

An exemplary parking assistance system with automated lateral and longitudinal guidance is described in the publication "Parking assistant with longitudinal and lateral guidance", Dirk Ahrens, 5th Conference Driver Assistance at the Technical University of Munich, Munich, 2012, which is available, for example, under the link "http: // mediatum. ub.tum.de/doc/1142099/1142099.pdf “is available on the Internet.

Parking assistance systems normally include a parking function for automated parking in parallel parking spaces and / or transverse parking spaces; optionally, a parking function for automated parking can also be provided.

Known parking assistance systems generally support rear parking along the lane in a parallel parking space lying parallel to the lane, the vehicle parking in reverse with automated lateral guidance and optionally automated longitudinal guidance in one or more trains along a calculated parking trajectory in the longitudinal parking space.

It is also known that parking assistance systems also support parking out of a longitudinal parking space and / or transverse parking space with automated lateral guidance and possibly automated longitudinal guidance.

Here, the vehicle is maneuvered out of a parking space with automated lateral guidance and preferably also automated longitudinal guidance and the vehicle is finally handed over to the driver.

During the maneuver out of a parallel parking space, for example, the vehicle is first led backwards parallel to the lane boundary in a first backward pull, then forward with a steering lock to the parking side in the forward direction and then - if necessary - reversed with a steering lock against the parking side in a backward pull. If necessary, one or more forward pulls with a steering lock to the parking side or reverse pulls with a steering lock against the parking side can then be carried out.

If a transfer position is reached after the automated parking maneuver has been carried out, the control of the vehicle is transferred to the driver. For this purpose, a takeover request is issued, for example as a text display on a screen in the vehicle cockpit. In known parking assistance systems for parking, the activation for drive, brake and steering is withdrawn with the takeover request. In the case of a vehicle with an automatic converter transmission, the vehicle rolls onto the road due to the creeping torque, and a steering angle that may have been predetermined by the parking assistance system changes in the direction of the zero position due to the retracted actuation. A steering lock generally goes back to the zero position if the steering is neither activated by the parking assistance system nor by the driver and has been driven a certain distance.

A handover to the driver after the end of the parking maneuver takes place, for example, in the event of a longitudinal parking space, when the vehicle can pass the front boundary object without collision while maintaining a predetermined safety distance.

Such a transfer process has the disadvantage that the driver must take over the vehicle guidance with lateral and longitudinal guidance and at the same time must observe the traffic behind, so that the driver can be overwhelmed in this situation.

It is an object of the invention to provide a parking assistance system for parking and a corresponding method for parking which overcomes this disadvantage.

The object is achieved by the features of the independent claims. Advantageous embodiments are described in the dependent claims. It is pointed out that additional features of a claim dependent on an independent claim without the features of the independent claim or only in combination with a subset of the features of the independent claim can form a separate invention that is independent of the combination of all features of the independent claim can be made the subject of an independent claim, a divisional application or a late application. This applies in the same way to the technical teachings described in the description, which can form an invention that is independent of the features of the independent claims.

A first aspect of the invention relates to a parking assistance system for a motor vehicle, for example for a passenger car, for automated parking with automated longitudinal and lateral guidance from a parking space, for example a longitudinal parking space. The vehicle is a vehicle with an automatic transmission, in particular with an automatic converter converter.

The parking assistance system is preferably also used for parking. However, this is not mandatory: it would be conceivable that the parking assistance system can only be used for parking.

If the parking assistance system is also used for parking, it can be provided that parking can only take place from one parking space, even if parking has already been automated in this parking space via the parking assistance system. However, this is not mandatory.

The parking assistance system is set up to carry out various activities described below. This is typically done by means of an electronic control unit, which can also be distributed over several control devices. The control unit can comprise one or more processors which operate in a manner according to the invention controlled by one or more software programs.

The parking assistance system is set up to actively keep the vehicle at a standstill after a transfer position for transferring the vehicle guidance to the driver has been reached, so that the vehicle does not start rolling. After reaching the transfer position, the vehicle is braked, for example by means of the service brake, in order to keep the vehicle at a standstill (before the transfer position is reached, the vehicle is braked down to a standstill, for example). Active stopping at a standstill is particularly necessary in the case of a converter automatic transmission, since the transmission of power is not completely interrupted when the transmission is coupled and the vehicle creeps when the transmission is not idling. The vehicle may also have to be stopped if the vehicle would otherwise roll due to an inclination of the driving surface.

A transfer position is reached in the case of parking out of a longitudinal parking space, for example, when the vehicle can pass the front boundary object in a manual forward pull from the transfer position while maintaining a predetermined safety distance without collision.

To take over vehicle control, the parking assistance system expects the driver to actuate the accelerator pedal.

When the driver's operation of the accelerator pedal is detected, the vehicle stops at a standstill. In the case of hard braking via the service brake, the braking is ended, in particular by ramp-like reduction of the braking torque of the service brake. The braking torque can be slowly ramped out to ensure particularly comfortable starting behavior. The braking torque is preferably reduced using a linear ramp. The braking torque is preferably reduced to zero, but it would be conceivable to first reduce the braking torque to a small remaining amount.

As a result of the transfer process according to the invention, the driver has enough time to observe the traffic on the road, to take over the guidance of the vehicle and to drive completely out of the parking space.

After reaching the transfer position, the steering is preferably held in a certain steering angle, in particular in the full steering angle, in order to prevent the steering from relaxing. In the case of a parking space from a longitudinal parking space, the steering is preferably turned toward the parking space when the transfer position has been reached (or shortly beforehand), so that the driver can leave the parking space particularly easily by means of a single manually performed forward pull. This steering lock is preferably held by the parking assistance system after the transfer position has been reached.

In response to the determination of the driver's actuation of the accelerator pedal, the holding of the steering lock is ended, ie the steering request is withdrawn. For example a curvature of the driving tube, which is converted by the steering control into a steering torque, is deactivated by the parking assistance system before the accelerator pedal is actuated, so that the steering torque drops to zero. For this purpose, for example, the parking assistance system sends a signal to the steering control unit, which indicates that a curvature specification no longer has to be implemented.

If the direction indicator was active during the automated parking maneuver (for example, because the parking assistance system activated the direction indicator independently or because the driver manually activated the direction indicator), the active light signal from the direction indicator is preferably canceled after the driver has actuated the accelerator pedal, especially after it has elapsed a predetermined period of time after the accelerator pedal is ascertained, for example after 5 s.

If the driver does not take over the vehicle guidance within a defined period of time by actuating the accelerator pedal, the vehicle is preferably secured in response to this by engaging a parking lock and / or an electric parking brake and the parking function is then terminated.

It is advantageous if, after reaching the transfer position, a takeover request for taking over the vehicle guidance is issued to the driver via a user interface, for example a text output on a screen in the vehicle cockpit. In this case, the output of the takeover request is preferably ended in response to the determination of the driver's actuation of the accelerator pedal.

• - Halten des Fahrzeugs im Stillstand nach Erreichen einer Übergabeposition;
• - Feststellen einer fahrerseitigen Betätigung des Fahrpedals; und
• - in Reaktion auf die Feststellung der fahrerseitigen Betätigung des Fahrpedals, Beenden des Haltens des Fahrzeugs im Stillstand.

A second aspect of the invention relates to a method for automated parking with an automated longitudinal and lateral guidance from a parking space on the part of a motor vehicle, with the steps:

• - holding the vehicle at a standstill after reaching a transfer position;
• - Determining a driver's operation of the accelerator pedal; and
• - in response to the detection of the driver's operation of the accelerator pedal, stopping the stopping of the vehicle at a standstill.

The above statements relating to the parking assistance system according to the first aspect of the invention apply correspondingly to the method according to the invention according to the second aspect of the invention. At this point, and advantageous embodiments of the method according to the invention not explicitly described in the claims correspond to the advantageous embodiments of the parking assistance system according to the invention described above or described in the claims.

A third aspect of the invention relates to software with program code for performing the method according to the second aspect of the invention if the software runs on a software-controlled device, for example on a control unit of the parking assistance system with one or more software-controlled processors.

• 1 ein Ablaufdiagramm zur Funktionsweise eines Ausführungsbeispiels eines erfindungsgemäßen Parkassistenzsystems zum Ausparken;
• 2a bis 2d eine Draufsicht über eine Ausparksituation; und
• 3 verschiedene Signalverläufe über der Zeit t.

The invention is described below using an exemplary embodiment with the aid of the accompanying drawings. In these show:

• 1 a flow diagram of the operation of an embodiment of a parking assistance system according to the invention for parking;
• 2a to 2d a top view of a parking situation; and
• 3 different waveforms over time t.

In 1 a simplified flow diagram for the functioning of an embodiment of a parking assistance system according to the invention for parking with automated longitudinal and transverse guidance is shown schematically.

In step 100 The driver activates the parking function, for example by switching on the ignition, selecting a parking menu on the screen in the center console by pressing a parking button, selecting the parking side and releasing the brake pedal.

Your own vehicle 1 is currently in the 2a shown position within the longitudinal parking space by the front boundary vehicle 2 and the rear boundary vehicle 3 and laterally through the curb 4 is limited.

Based on the information about the vehicle's surroundings, the parking assistance system calculates a multi-way parking trajectory. During the execution of the parking maneuver, this parking trajectory is adjusted based on updated information about the vehicle environment.

The automated parking maneuver begins in step 110 with a straight backward pull 10 parallel to the curb 4 , the vehicle being reset until a certain threshold value for the distance to the rear vehicle 3 is reached or undercut. For this, the parking assist system engages the reverse gear and that Vehicle accelerates and in front of the rear vehicle 3 brought to a standstill.

In 2a becomes the reverse move 10 illustrated by the path of a vehicle reference point. In this example, the center of the rear axle is used as the vehicle reference point.

In 2 B the situation after performing the initial backward pull is shown.

The steerable wheels 5a . 5b are now - as already in 2 B shown - fully turned in the direction of the parking area and - after automatically changing the direction of travel - it turns into 2 B forward train described by the train 20 carried out with full steering lock towards the parking side (see step 120 ).

In 2c is the situation after the end of the forward move 20 shown.

During the forward move 20 or immediately after the end of the forward move is in the query 130 checked whether the vehicle 1 the longitudinal parking space after a future straight backward pull through a subsequent manual forward pull with the wheels fully turned 5a . 5b Could leave towards the parking side, ie whether the vehicle 1 after a (future) straight backward pull and a subsequent full turning of the wheels 5a . 5b the front vehicle 2 can maintain a predetermined safety distance in a forward pull made manually by the driver. The test therefore takes place before the possible straight reverse pull.

If this is the case - after changing the direction of travel and straightening the wheels 5a . 5b - the in 2d just shown reverse pull 30 carried out by the parking assistance system (see step 140 ). In 2d the vehicle is already shown in the position after the straight reverse pull has ended.

• Wenn in einer Prüfung gemäß Schritt 135 festgestellt wird, dass die Parklücke nach einem zukünftigen Rückwärtszug mit Volleinschlag entgegen der Richtung der Ausparkseite in einem manuellen Vorwärtszug mit Volleinschlag Richtung Ausparkseite verlassen werden könnte, wird der Rückwärtszug mit vollem Lenkeinschlag durchgeführt (s. Schritt 150); in diesem Fall ist dieser Zug der letzte Zug des automatisierten Fahrmanövers.

If the result of the test in step 130 is negative, a reverse pull with full steering angle is carried out against the direction of the parking space (see step 150 or alternatively step 160 ). A distinction is made between two cases:

• If in an exam according to step 135 If it is determined that the parking space could be left after a future reverse pull with full lock against the direction of the parking side in a manual forward pull with full lock towards the parking side, the reverse pull is carried out with full steering lock (see step 150 ); in this case this train is the last train of the automated driving maneuver.

If, on the other hand, the test according to step 135 is negative, is after the then reverse pull with full impact (see step 160 ) another forward move (see step 120 ) necessary to be followed in the course of 1 always followed by a reverse train.

After completing the straight reverse pull according to step 140 or according to the reverse pull 150 the wheels are steered in the full turn towards the parking space (see step 170 ).

The vehicle is now in the transfer position; the vehicle control can be handed over to the driver.

This is done in step 180 a message about the successful completion of the automated parking maneuver and a takeover prompt on the screen in the cockpit (eg "Parking maneuver completed. Please take over vehicle control."). After this information has been shown, the vehicle is still actively braked by the parking assistance function using the service brake so that the vehicle does not roll away. At the same time, the steering is held fully in order to prevent the steering from relaxing. In this state, the driver can guide the vehicle with a simple actuation of the accelerator pedal 1 take. If in step 190 it is determined that the driver is driving the vehicle 1 wants to take over by actuating the accelerator pedal, the actuation of the accelerator pedal leads to the braking torque being slowly reduced in a ramp shape in order to ensure comfortable starting behavior (see step 200 ). Furthermore, in step 200 the steering request was also withdrawn. In addition, in step 200 the control of the turn signal in the parking direction, which was output during the entire parking maneuver, is withdrawn after a certain period of time has elapsed after the accelerator pedal has been actuated, so that the turn signal stops flashing.

If the driver does not drive the vehicle within the time period Δt (e.g. Δt = 5s) from the issue of the takeover request 1 by pressing the accelerator pedal, the vehicle is secured by engaging drive position P (ie engaging the parking lock) (see step 210 ) and the function ends.

At the in 1 as the last parking pull, a reverse pull is always carried out, either as a straight reverse pull (see step 140 ) or as a steered reverse pull (see step 135 ).

The transfer process is carried out with the help of 3 explained in more detail by way of example.

Diagram a) shows the time profile of a signal FP over time t, which indicates the actuation state of the accelerator pedal. This signal FP is from the engine control unit of the motor vehicle 1 delivered to the control unit of the parking assistance system via a vehicle bus and evaluated by the parking assistance system in order to determine whether the accelerator pedal has been actuated. If the accelerator pedal is not operated, the signal FP has the signal value W _{FP, 1st} (e.g. W _{FP, 1} = 0). When the accelerator pedal is operated, the signal FP has the signal value W _{FP, 2nd} (e.g. W _{FP, 2} = 1).

Diagram b) shows the time course of the target braking torque M _B , which is specified by the parking assistance system of the brake control for controlling the service brake.

auf.Diagram c) shows the course of time of a signal SKU, which indicates whether a desired curvature κ, which specifies the curvature of the driving hose and thus also the steering angle, should be implemented by the steering control. If no desired curvature κ is to be implemented, the signal SKU has the signal value W _{SKU, 1} (e.g. W _{SKU, 1} = 0). If a target curvature κ is to be implemented, the signal has the signal value $${\text{W}}_{\text{SKU}.\text{2}}\left(\text{z}\text{.B}{\text{, W}}_{\text{SKU}.\text{2}}=1\right)$$

on.

At the time to, the message appears that the parking maneuver has been successfully completed and the driver should take over the driving task. At this point the vehicle 1 still actively braked by the parking assistance system in that the steering control's parking assistance system has a correspondingly large value M _{B, FB} for the target braking torque M _B pretends. At the same time, the steering is kept in full lock; the parking assistance system gives the steering control over the value W _{SKU, 2nd} for the signal SKU that a target curvature κ, which corresponds to the full turn in the direction of the parking space, should be maintained.

At the time t ₁ is changed to FP by changing the signal FP W _{FP, 2nd} actuation of the accelerator pedal on the part of the parking assistance system is determined.

The determination of the actuation of the accelerator pedal leads to the braking torque M _B is slowly ramped out to ensure comfortable starting behavior. Furthermore, when the actuation of the accelerator pedal is determined, the steering request is withdrawn by the SKU signal being set to the value W _{SKU, 1} switches so that the target curvature κ, which corresponds to the full turn in the direction of the parking space, is no longer to be implemented. The steering torque specified by the steering control therefore drops to zero.

Claims (8)

Parking assistance system for a motor vehicle (1), for automated parking with automated longitudinal and lateral guidance from a parking space, the parking assistance system being set up, - after reaching a transfer position for transferring the vehicle guidance to the driver, to keep the vehicle (1) at a standstill, - determine a driver's operation of the accelerator pedal, and - In response to the determination of the driver's actuation of the accelerator pedal, stop the vehicle (1) at a standstill. Parking assistance system after Claim 1 , wherein the parking assistance system is set up, - after reaching the transfer position, using the service brake to brake the vehicle (1) in order to keep the vehicle (1) at a standstill, and - in response to the driver's actuation of the accelerator pedal, braking the vehicle (1) to end, in particular by ramp-reducing the braking torque (M _B ) of the service brake. Parking assistance system according to one of the preceding claims, wherein the parking assistance system is set up, - After reaching the transfer position to keep the steering in a steering lock, in particular a full lock, and - in response to the detection of the driver's operation of the accelerator pedal, to stop holding the steering lock. Parking assistance system according to one of the preceding claims, wherein the parking assistance system is set up to cancel the light signal of a direction indicator which is active during the parking maneuver after the driver has actuated the accelerator pedal, in particular after a predetermined period of time has elapsed from the detection of the actuation of the accelerator pedal. Parking assistance system according to one of the preceding claims, wherein the parking assistance system is set up to determine that the driver has not actuated the accelerator pedal within a defined period of time, and in response to securing the vehicle by engaging a parking lock and / or a parking brake. Parking assistance system according to one of the preceding claims, wherein the parking assistance system is set up, - after reaching the handover position, to issue a takeover request to take over the vehicle guidance and / or a message about the termination of the automated parking maneuver to the driver via a user interface, and - In response to the detection of the driver's actuation of the accelerator pedal, end the output of the takeover request and / or message. Method for automated parking with automated longitudinal and lateral guidance from a parking space on the part of a motor vehicle (1), comprising the steps: - Holding the vehicle (1) at a standstill after reaching a transfer position; - Determining a driver's operation of the accelerator pedal; and - In response to the detection of the driver's operation of the accelerator pedal, stopping the holding of the vehicle (1) at a standstill. Software with program code to carry out the procedure according to Claim 7 if the software runs on a software controlled device.

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