GB2486814A

GB2486814A - Method for assisting a driver of a motor vehicle

Info

Publication number: GB2486814A
Application number: GB201122008A
Authority: GB
Inventors: Michael Seiter; Florian Raisch
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-12-21
Filing date: 2011-12-20
Publication date: 2012-06-27
Anticipated expiration: 2031-12-20
Also published as: FR2969098A1; GB2486814B; DE102010063801A1; GB201122008D0

Abstract

A method for assisting a driver of a motor vehicle during a driving manoeuvre such as parking, in which firstly an environment of the vehicle is detected, for example by a camera, and acquired data stored, in a second step at least part of the environment is redetected, or example by sensors such as ultrasonic infrared, radar or LIDAR sensors, and the data acquired therein are compared with the previously stored data. On the basis of the acquired data, a trajectory along which the driving manoeuvre can be carried out is determined, the trajectory being calculated such that no objects lie in the driving tube. If it is recognised that the object is moving and a collision may occur, the driving manoeuvre is aborted and the control over the vehicle is returned to the driver. The invention also relates to a device for carrying out the method.

Description

Method for assisting a driver of a motor vehicle

Prior art

The invention relates to a method for assisting a driver of a motor vehicle during a driving manoeuvre, in which, while driving past, data of a parking space are acquired and on the basis of the acquired data a trajectory along which the vehicle can be parked in the parking space is determined.

Furthermore, the invention starts from a device for carrying out the method according to the preamble of Claim 9.

In methods for assisting a driver of a motor vehicle during a driving manoeuvre, a distinction is made between semi- automatic methods and fully automatic methods. In semi-automatic methods, a trajectory is calculated and the driver is given instructions on how he has to move the vehicle to carry out the driving manoeuvre along the trajectory. Furthermore, there are also systems in which the longitudinal guidance, i.e. acceleration, maintaining the speed and braking of the vehicle, are the responsibility of the driver and the steering movements are controlled by the driving assistance system. Finally, systems are also known in which the driving manoeuvre is carried out fully automatically, i.e. longitudinal and transverse movements of the vehicle are taken over by the parking assistance system. Driving manoeuvres in which the method is used are normally driving manoeuvres for parking in a parking space.

In all systems, during the driving manoeuvre, the environment of the vehicle is detected and distances to objects in the environment of the vehicle are indicated to the driver.

Thus, for example, DE-A-l03 39 645 discloses a method in which the size and *position of a parking space in relation to a vehicle while the vehicle is driving past the parking space is determined, ultrasonic sensors being used to determine the dimensions of the parking space. From the data thus acquired, a desired trajectory for parking the vehicle in the parking space is calculated. To determine the dimensions of the parking space, use is made of a first sensor with which the width of a parking space arranged transversely to the driving direction is determined. With a second sensor, which has a greater sensitivity than the first sensor, the depth of the parking space is measured.

In order to exclude ground echoes, the distance signals of both sensors are evaluated in the overlapping detection region on the basis of position signal transmitters.

Possible moving objects which may be present in the region of the parking space are not discussed.

Disclosure of the invention

Advantages of the invention Since it according to the invention to method for assisting a driver of a motor vehicle during a driving manoeuvre comprises the following steps: (a) detecting the environment of the vehicle before carrying out the driving manoeuvre, and storing the acquired data, (b) redetecting at least part of the environment and comparing the data acquired therein with the data stored in step (a), (c) determining a trajectory along which the driving manoeuvre can be carried out, the trajectory being calculated on the basis of the acquired data such that no objects lie in the driving tube, (d) aborting the driving manoeuvre if it is recognised that an object is moving in the driving tube or into the driving tube and returning the control over the vehicle to the driver.

The method according to the invention makes it possible to carry out the driving manoeuvre along the calculated trajectory as long as a driving tube defined by the trajectory is free from objects. As soon as an object comes into the driving tube, the control is handed over to the driver. If, owing to the movement of the object, the driver can assess that there is no danger of collision with the object, the driving manoeuvre along the calculated trajectory can be continued. If a collision with the object is to be expected, the driving manoeuvre is preferably aborted. The decision to continue or abort the driving manoeuvre here is the responsibility of the driver to which the control over the vehicle has been handed over. In this way, the possibility of a collision with a moving object occurring is avoided. The safety during the driving manoeuvre is thus increased.

In the context of the present invention, driving tube refers to the region which is covered by the vehicle during the driving manoeuvre. In each case here the regions of the vehicle projecting furthest outwards during the parking manoeuvre are taken into consideration. Thus, the driving tube when reversing in a right-hand curve is defined, for example, by the area covered by the connecting line between the left front corner and right rear corner. Accordingly, in a left-hand curve the front right corner and the rear left corner are considered to be the boundary of the driving tube.

Trajectory refers to the path along which the vehicle moves. This is normally defined as the path travelled by the centre point of the rear axle. Alternatively, however, it is also possible to use any other point on the vehicle to define the trajectory. Thus, for example, the centre point of the front axle or the centre point of the vehicle may also be used to define the trajectory. Normally, however, the trajectory refers to the path travelled by the centre point of the rear axle.

For the method according to the invention, i a first step the environment of the vehicle is detected. In particular, the region in which the planned driving manoeuvre is to be carried out is detected here. In the case of a driving manoeuvre on narrow roads or paths, the environment is, for example, the region in front of the vehicle during a driving manoeuvre carried out forwards. In the case of a manoeuvre which may include forward movements and rearward -5-.

movements, the region in front of and behind the vehicle is detected. Particularly preferably, the method is suitable for driving manoeuvres for parking in a parking space, referred to as parking manoeuvres below.

On use of the method according to the invention during a parking manoeuvre, the parking space is preferably detected in a first step while driving past. The detecting of the parking space is effected by suitable sensors which determine the distance of objects to the vehicle. Suitable sensors for this are, for example, ultrasonic sensors, infrared sensors, radar sensors, LIDAR sensors and optical sensors, for example cameras. In contrast to sensors which transmit a signal and receive a reflected echo of the signal and determine from the delay time the distance to an object, the detection of the environment in the case of optical sensors, in particular cameras, is effected by suitable image processing.

Ultrasonic sensors or else cameras are preferably used for detecting a parking space.

The data acquired by the sensors are stored in a data store. It is particularly advantageous here if a map of the surroundings of the vehicle is calculated from the data and the data in the form of this map are stored in the store.

A collision with an object is expected, for example, if an object moves towards the vehicle within the field of view of the sensors used to detect the environment, and the trajectories of the object envelope of the vehicle and of the object moving towards the vehicle intersect. A collision is also expected if the vehicle envelope and object envelope of an object assumed to be stationary at the last point of measurement touch when the vehicle moves further along the trajectory. The object is assumed to be stationary at the last point of measurement if the object is initially detected and then goes out of the detection range of the sensors. Since it is no longer possible to follow the object, it is assumed that the object is no longer moving but remains at the place where it was last measured. The departure of the object from the detection range of the sensors may be caused on the one hand by a movement of the object or by the movement of the vehicle and is generally attributed to the fact that the sensors used do not cover the entire region around the vehicle but normally only the region in front of the vehicle and the region behind the vehicle. The region laterally beside the vehicle is generally not covered by the detection range of the sensors. Furthermore, it is also possible to estimate, on the basis of the movement data of a detected object, how the object will move on after leaving the detection range of the sensors. In this case, a collision is expected if the trajectory of the object envelope and the trajectory of the vehicle envelope intersect or touch.

From the data acquired while driving past, it is firstly determined whether the detected parking space is of sufficient size for parking the vehicle. All the objects and obstacles situated in the region of the parking space are taken into consideration here. If the parking space is of sufficient size and there are no obstacles situated in the region of the parking space, a trajectory along which the vehicle can be parked in the parking space is calculated on the basis of the data acquired and stored in the store. The trajectory is calculated here on the basis of the acquired data such that no objects lie in the driving tube when the vehicle drives along the calculated traj ectory.

In the case of a single detection of the environment of the vehicle, however, the possibility of objects moving into the region of the intended parking space is not taken into consideration. Such objects may be, for example, vehicles, for example also two-wheeled vehicles, pedestrians or else objects flying around, for example toys, e.g. balls.

In order to avoid collision of the vehicle with the moving object when control of the vehicle is returned to the driver, it is preferable for the vehicle first to stop on recognition of a moving object. To this end, it is, for example, possible to deliver a corresponding command to a control unit of an electronic stability programme (ESP), by which the brakes of the vehicle can be controlled.

An object is, for example, recognised as a moving object if the data of the environment acquired in step (b) differ from the data acquired in step (a). As a result of a difference of the data, it is recognised that an object which was detected in the first detection is no longer situated at its original position. This indicates a moving object. If the assumption is made that there is no danger of collision with the moving object, for example if it is recognised on the detection that the object is moving further away from the vehicle and not in the direction of the vehicle or in the direction of the driving tube, it is not necessary for the process to be aborted. Handing over the control to the driver is only necessary if the object is moving in the direction of the driving tube or even into the driving tube. Provided that the object is moving quickly and it is recognised that the object is no longer in the driving tube when the vehicle has reached the corresponding position, it is likewise not necessary to hand over the control to the driver. In addition, it is, however, also possible to abort the process if an object moving outside the driving tube is detected. In particular, it may possibly be expected here that the object changes its direction of movement and comes into the driving tube.

For this reason, it is sensible for the driver to concentrate fully on the object and have control over the driving manoeuvre himself.

The handover of the control to the driver can mean, on the one hand, that the full control over the vehicle is handed over to the driver and the driving assistance system which assists the driver during the parking procedure delivers no further information. Alternatively, it is also possible for merely the control over longitudinal and transverse guidance of the vehicle tc be handed over to the driver, but the driver continues to receive instructions for steering the vehicle from the parking assistance system, in order to drive on the previously calculated trajectory and park the vehicle along the latter in the parking space.

Furthermore, it is also possible for the manoeuvre to be interrupted. In this case, it is possible to restart the manoeuvre if the positicn of the vehicle after the reaction taken by the driver allows resumption.

The detection of the environment cf the vehicle in step (a) and the redetecting of at least part of the environment in step (b) can be effected at short intervals one after the other, or else the detecting in step (b) is only carried out after the determination of the trajectory along which the vehicle can drive into the parking space. Furthermore, it is also possible to carry out continuous measurements, it being possible in this case, for example, to store in each case the data of the preceding, at least one measurement and compare these data with the following measurement. Here too, it is expedient to keep the data, acquired while driving past in step (a), stored as a map over the entire period during the driving manoeuvre. As a result of the plurality of following measurements, it can then be detected in what direction and at what speed an object is moving. This can be taken into consideration in the assessment of whether the driving manoeuvre is to be aborted and the control handed back to the driver.

For economical monitoring, it is furthermore possible for the redetection of at least part of the environment in step (b) to relate only to the part of the environment of the vehicle which is covered by the vehicle during the driving manoeuvre, i.e. in particular to the provided driving tube and a region beside the driving tube, in order to compensate for inaccuracies of the measurement.

Furthermore, it is also possible for the part ot the environment which is redetected in step (b) to relate to only a partial region of the driving tube, and this region is to be chosen with such a size that the vehicle can be stopped in good time before a possible collision with an object. The region is thus in particular dependent on the speed at which the vehicle is moving. The slower the speed, the smaller is the region that can be chosen.

It is also possible, for example, to redetect only the part of the environment of the vehicle in step (b) in which an -10 -object was recognised during the detection of the environment in step (a) . In this case, all that is monitored is whether the object which was originally recognised is moving, or whether it is a stationary object.

By continuous monitoring of the environment of the vehicle, it is furthermore also possible to realise whether an object which was recognised initially as a stationary object subsequently, however, starts to move. This is, for example, possible if the initially detected, stationary object is a parking vehicle which at a subsequent point in time drives off. A pedestrian who is initially standing at a point on the road and then starts to run away is also an object which is initially stationary and svbsequently starts moving. Also in the case where an object is detected which is initially stationary and at a subsequent point in time starts moving, the control over the vehicle is handed back to the driver.

In order to make the driver aware that the dontrol is being returned, it is furthermore advantageous to give the driver corresponding information. This can be effected, for example, by an indication in a display, for example a display of a navigation system. It is also possible to provide a separate error display in the region of the dashboard, on which such information is displayed.

In a preferred embodiment of the invention, for the detection of the environment of the vehicle -as already mentioned above -at least one camera is used and the data of the environment are obtained by image processing. It is possible here to use any desired, suitable image processing system with which a map of the environment of the vehicle -11 -can be produced from image data. with the aid of the image processing, it must be possible firstly to detect the distance to objects and the direction in which the objects are situated.

If the detection of the surroundings of the vehicle in step (a) is effected by a camera, the images of which have been evaluated by image processing, it is advantageous to carry out the further detection of at least part of the environment with the sensors which have been used for the detection of the environment of the vehicle in step (a), are different.

The use of different sensors for the detection of the environment of the vehicle in step (a) and for the redetecting of the environment in step (b) may, however, also be expedient with sensors different from cameras for the detection in step (a). In particular, it is possible, for example by using different sensors, to eliminate possible sources of errors resulting from the use of a certain type of sensor.

By using different sensors, the detection in step (a) can also be verified. Thus, for example, it is possible to detect the parking space by two different types of sensors simultaneously and to compare the respectively acquired data with one another. If differences are found with a simultaneous detection, it may be assumed that one of the measurements is incorrect. In this case, it is expedient to inform the driver and repeat the measurement.

It is, however, also expedient, in the case where the environment is detected while driving past only with one -12 -type of sensor, to carry out the redetecting (b) by a type of sensor different from the type of sensor used in step (a). Thus, for example, it is possible, in the case where a camera is used when detecting the environment in step (a), to use distance sensors for detecting the at least part of the environment in step (b). The distance sensors used in this case, as already mentioned above, are for example ultrasonic sensors, infrared sensors, radar sensors or LIDAR sensors. If a camera is not used for detecting the environment of the vehicle in step (a), it is also possible here to use a distance sensor, as described above.

Furthermore, it is also possible to carry out the redetecting of the environment in step (b) with a camera and to process the data acquired with the camera by image processing. It is also possible to carry out both the detecting of the environment in step (a) and the redetecting of the environment in step (b) with a canera in each case. The sane camera can also be used here in each case. Besides using only one type of sensor for the detection of the environment of the vehicle, it is also possible to detect the environment of the vehicle by simultaneous use of different types of sensors.

A device according to the invention for carrying out the method comprises sensors for detecting the environment of the vehicle, storage means for storing the data acquired with the sensors, and means for calculating a trajectory along which the driving manoeuvre can be carried out. The device further comprises means with which the stored data can be compared with data acquired during a second measurement, and means for aborting the manoeuvre if the data of the first and second measurement differ.

-13 -As already mentioned above, the sensors for detecting the environment of the vehicle are, for example, ultrasonic sensors, infrared sensors, radar sensors and LIDAR sensors, or else cameras for detecting the environment.

The storage means for storing the data acquired with the sensors may be any desired data stores known to a person skilled in the art. Customary storage means are, for example, magnetic stores or optical stores. Preference is given to volatile stores (RAM) for storing the data.

The means for calculating a trajectory along which the driving manoeuvre can be carried out, and the means for comparing the two measurements acquiring data comprise, for example, a control unit of a driving system. In particular, it is necessary for the means for calculating the trajectory and the means for comparing the data of the two measurements to comprise a processor which allows the evaluation of the data and the calculation of the trajectory. In particular for determining the distance from objects for detecting the environment of the vehicle, it is also possible for the individual sensors in each case to be connected to an evaluating unit, where the evaluating unit may be a component of the sensor. As in this case, the data on the environment acquired by the evaluating unit are firstly merged to form a map of the environment and this map is transferred to the storage medium for storage. The merging to form the map of the environment can be effected here either in a separate unit, or else in one of the evaluating units of the sensors.

It is preferred if the means for detecting the environment of the vehicle and for calculating the trajectory are a -14 -control unit of a driving assistance system, for example a parking assistance system.

If a difference is found with the means for comparing the data acquired during the two measurements, a signal is generated and is transmitted to the means for aborting the manoeuvre. A suitable means for aborting the manoeuvre is, for example, a control unit of an electronic stability programme which communicates with the brakes of the vehicle and thus can control the brakes in order to stop the vehicle. The stopping of the vehicle avoids the situation where an uncoordinated rolling-on of the vehicle can result in a collision with an object. In addition, the driver thereby also receives a clear indication that the manoeuvre is aborted and he has to take over the control himself.

Besides the above-described variant in which the comparison of the stored data with the data of a second measurement is carried out in the control unit of the driving assistance system, it is also possible to use the control unit, for example, of the electronic stability programme to compare the data. In this case, it is not necessary first to transmit a signal from the control unit of the driving assistance system to the control unit of the electronic stability programme.

In addition to the indication to the driver by stopping of the vehicle, it is advantageous if indicating means are included which can indicate to the driver that the manoeuvre has been aborted. In this case, as the indicating means, for example an indicating unit in the dashboard of the vehicle which issues warnings, can be used, a visual signal can be given, for example by a warning lamp, or else -15 -a screen, for example a screen of a navigation system, can be used.

Claims

-16 -Claims 1. A method for assisting a driver of a motor vehicle during a driving manoeuvre, comprising the following steps: (a) detecting the environment of the vehicle before carrying out the driving manoeuvre, and storing the acquired data, (b) redetecting at least part of the environment and comparing the data acquired therein with the data stored in step (a), (c) determining a trajectory along which the driving manoeuvre can be carried out, the trajectory being calculated on the basis of the acquired data such that no objects lie in the driving tube, (d) aborting the driving manoeuvre if it is recognised that an object is moving in the driving tube or intothe driving tube and returning the control over the vehicle to the driver.
2. A method according to Claim 1, characterised in that an object is recognised as a moving object if the data of the environment acquired in step (b) differ from the data acquired in step (a).
3. A method according to Claim 1 or 2, characterised in that in step (b) the part of the environment of the vehicle in which an object was recognised is detected.

-17 -
4. A method according to one of Claims 1 to 3, characterised in that, for the detection of the environment of the vehicle, at least one camera is used and the data of the environment are obtained by image processing.
5. A method according to one of Claims 1 to 4, characte±ised in that different sensors are used for the detection of the environment of the vehicle in step (a) and for the redetecting of the environment in step (ID).
6. A method according to Claim 4 or 5, characterised in that a camera is used for detecting the environment in step (a), and distance sensors are used for the detecting in step (b)
7. A method according to Claim 6, characterised in that the distance sensors are ultrasonic sensors, infrared sensors, radar sensors or LIDAR sensors.
8. A method according to one of Claims 1 to 7, characterised in that the driver is informed via indicating means if the manoeuvre is aborted.
9. A method according to one of Claims 1 to 8, characterised in that the driving manoeuvre is a parking manoeuvre into a parking space.
10. A method according to Claim 9, characterised in that in step (a) the parking space is detected while driving past and the acquired data are stored.-18 -
11. A method for assisting a driver of a motor vehicle substantially as herein described.
12. A device for carrying out the method according to one of Claims 1 to 11, comprising sensors for detecting the environment of the vehicle, storage means for storing the data acquired with the sensors, and means for calculating a trajectory along which the driving manoeuvre can be carried out, characterised in that the device further comprises means with which the stored data can be compared with data acquired during a second measurement, and means for aborting the driving manoeuvre if the data of the first and second measurement differ.
13. A device according to Claim 12, characterised in that the means for calculating a trajectory and the means for comparing the data acquired during the two measurements comprise a control unit of a driving assistance system.
14. A device according to Claim 13, characterised in that indicating means are included which can indicate to the driver that the manoeuvre has been aborted.14. A device substantially as herein described.