TECHNICAL FIELD The invention relates to a method for controlling driving of a vehicle along a road according to the preamble of claim 1 . The invention also relates to a system for controlling driving of a vehicle along a road. The invention also relates to a vehicle. The invention in addition relates to a computer program and a computer program product.

BACKGROUND ART

For controlling driving of a vehicle along a road vehicles are sometimes equipped with a forward looking detector for detecting the trajectory of the lane of the road along which the vehicle is travelling, usually by detecting the road markers marking the lane in which the vehicle is travelling. The driving of the vehicle along the lane including the speed of the vehicle may hereby be controlled based upon the thus detected trajectory. Such control of the driving of the vehicle is called Lane Keep Assistance, LKA.

A problem with such a lane keep assistance function is that it sometimes is difficult to visually detect road marks, e.g. in connection to road exits and entrances where it may be difficult to determine which markers to follow, i.e. base the control of the driving on. Road marks may also be worn away from the road, be hidden under snow or the like, and be merged together due to reduction of number of lanes. There may also be temporary road marks due to e.g. roadworks.

Automatically following false road marks or other lines by means of a lane keep assistance function may in worst case lead to severe accidents. There is thus a need for improving controlling driving of a vehicle along a road.

OBJECTS OF THE INVENTION

An object of the present invention is to provide a method for controlling driving of a vehicle along a road which improves safety and accuracy in keeping the vehicle in the lane of the road along which the vehicle is travelling.

Another object of the present invention is to provide a system for controlling driving of a vehicle along a road which improves safety and accuracy in keeping the vehicle in the lane of the road along which the vehicle is travelling.

SUMMARY OF THE INVENTION

These and other objects, apparent from the following description, are achieved by a method, a system, a vehicle, a computer program and a computer program product, as set out in the appended independent claims. Preferred embodiments of the method and the system are defined in appended dependent claims.

Specifically an object of the invention is achieved by a method for facilitating driving of a vehicle along a road. The method comprises the steps of: tracking a vehicle along the road ahead of said vehicle; determining a historic trail of the vehicle being tracked; and following a thus determined historic trail during driving of the vehicle.

Hereby safer drive is facilitated in that the vehicle will follow a trail which is drivable as the tracked vehicle has been driving along the trajectory corresponding to the historic trail. Hereby a proper trajectory is provided for the vehicle to follow so that the vehicle will be assisted in keeping the lane of the tracked vehicle without the need for lane keep assistance function or as a redundancy to a lane keep assistance function if it is malfunctioning due to road marks or the like not being visible/detectable. The vehicle will be assisted in driving independent of whether map data exists/is available/if false and/or whether it is possible to detect road marks. The thus determined historic trail may thus be used as a redundancy to map data and/or trajectory of the road obtained from road marks. The thus determined historic trail may be used where map data has not been updated, for example if the road has been changed by adding/changing lanes, adding a roundabout or the like, if the map data is temporarily wrong due to e.g. construction work or temporary obstacle or the like.

By thus following a thus determined historic trail during driving of the vehicle a possible obstacle for which the tracked vehicle which historic trail is being followed has avoided by bypassing the obstacle will be automatically avoided by following the historic trail. Thus, safety is further improved. The thus determined historic trail may be used as a basis for controlling the vehicle along the road when the vehicle is driving in the lane corresponding to the historic trail, said control of the vehicle comprising keeping the vehicle on the historic trail. This thus provides for efficient driver assistance and facilitates efficient autonomous drive. This provides for efficient positioning of the vehicle on the road during driving along the road.

According to an embodiment of the method the step of following a thus determined historic trail during driving of the vehicle comprises controlling driving of the vehicle based upon said determined historic trail. By thus controlling driving based upon the historic trail safety is improved. The control of the vehicle may hereby be handled automatically based upon the historic trail.

According to an embodiment of the method the step of controlling driving of the vehicle based upon said determined historic trail comprises keeping the vehicle on the thus determined historic trail. Hereby safety of driving the vehicle is improved. Thus, an efficient and reliable way of keeping the vehicle on a lane where another vehicle has driven is hereby obtained.

According to an embodiment the method further comprises the steps of: continuously determining whether the vehicle is following the thus determined historic trail; and providing a warning to the operator of the vehicle if driving of the vehicle deviates from said determined historic trail to a predetermined extent. This further improves safety in that the operator/driver may take actions based upon the warning. The driver will hereby be informed if the vehicle deviates from the historic trail and may thus avoid an accident due to such deviation.

According to an embodiment of the method the step of determining a historic trail comprises detecting the vehicle being tracked so as to obtain waypoints of earlier positions of the tracked vehicle; based upon said waypoints creating the historic trail of said tracked vehicle. Hereby an easy and efficient way of obtaining the historic trail based upon a vehicle ahead is obtained.

Specifically an object of the invention is achieved by a system for controlling driving of a vehicle along a road. The system comprises means for tracking a vehicle along the road ahead of said vehicle; means for determining a historic trail of the vehicle being tracked; and means for following a thus determined historic trail during driving of the vehicle.

According to an embodiment of the system the means for following a thus determined historic trail during driving of the vehicle comprises means for controlling driving of the vehicle based upon said determined historic trail.

According to an embodiment of the system the means for controlling driving of the vehicle based upon said determined historic trail comprises means for keeping the vehicle on the thus determined historic trail

According to an embodiment the system further comprises means for continuously determining whether the vehicle is following the thus determined historic trail; and means for providing a warning to the operator of the vehicle if driving of the vehicle deviates from said determined historic trail to a predetermined extent.

According to an embodiment of the system the means for determining a historic trail comprises means for detecting the vehicle being tracked so as to obtain waypoints of earlier positions of the tracked vehicle; and means for creating the historic trail of said tracked vehicle based upon said waypoints.

The system for controlling driving of a vehicle along a road is adapted to perform the methods as set out herein. The system according to the invention has the advantages according to the corresponding method claims.

Specifically an object of the invention is achieved by a vehicle comprising a system as set out herein.

Specifically an object of the invention is achieved by a computer program for controlling driving of a vehicle along a road, said computer program comprising program code which, when run on an electronic control unit or another computer connected to the electronic control unit, causes the electronic control unit to perform methods as set out herein.

Specifically an object of the invention is achieved by a computer program product comprising a digital storage medium storing the computer program.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention reference is made to the following detailed description when read in conjunction with the accompanying drawings, wherein like reference characters refer to like parts throughout the several views, and in which: Fig. 1 schematically illustrates a side view of a vehicle according to the present invention;

Fig. 2a schematically illustrates a road with two lanes with a road exit;

Fig. 2b schematically illustrates a road where the lanes have been redirected due to a road construction ahead;

Fig. 3 schematically illustrates a block diagram of a system for controlling driving of a vehicle along a road according to an embodiment of the present invention;

Fig. 4 schematically illustrates a block diagram of a method for controlling driving of a vehicle along a road according to an embodiment of the present invention;

Fig. 5 schematically illustrates a computer according to an embodiment of the present invention and

Fig. 6 is a flowchart illustrating steps performed when selecting a vehicle to follow.

DETAILED DESCRIPTION

Hereinafter the term "link" refers to a communication link which may be a physical connector, such as an optoelectronic communication wire, or a non- physical connector such as a wireless connection, for example a radio or microwave link.

Hereinafter the term "trajectory of the road" and "trajectory of the lane of the road" comprises the extension of the road/lane, the course of the road/lane and comprises the curvature of the road/lane. Fig. 1 schematically illustrates a side view of a vehicle 1 according to the present invention. The exemplified vehicle 1 is a heavy vehicle in the shape of a truck. The vehicle according to the present invention could be any suitable vehicle such as a bus or a car. The vehicle comprises a system I for controlling driving of the vehicle 1 along a road R.

Fig. 2a schematically illustrates a road R with two lanes L1 , L2, a first lane L1 in which a vehicle 1 was travelling and a second lane L2 adjacent to the first lane L1 . From the first lane L1 a road exit of a lane L3 with a certain extension exists. In the road exit a second vehicle 2 ahead of the first vehicle 1 has taken off and is travelling in the lane L3.

The vehicle 1 comprises a system I for facilitating driving of a vehicle along a road. The system I comprises means for tracking a vehicle along the road ahead of said vehicle. The system I comprises a detector unit D for detecting vehicles ahead of the vehicle so as to track vehicles ahead of said vehicle 1 . The system I comprises means for determining a historic trail of the vehicle being tracked. The means for determining a historic trail of the vehicle being tracked comprises the detector unit D.

In the example in fig. 2a the vehicle 1 is tracking the vehicle 2 having taken off on the lane L3. By means of the system I the vehicle 1 is determining a historic trail T1 of the vehicle 2.

The vehicle 1 is following a thus determined historic trail T1 during driving of the vehicle 1 . As the historic trail T1 of the tracked vehicle 2 is running in the road exit and further in the lane L3, the vehicle 1 following the historic trail T1 is taking off on the road exit and is driving on the lane L3.

According to a variant the system I is controlling driving of the vehicle based upon that determined historic trail T1 as the vehicle 1 is following the thus determined historic trail T1 . Controlling driving of the vehicle based upon said determined historic trail T1 comprises keeping the vehicle on the thus determined historic trail T1 . Controlling driving comprises adapting the speed of the vehicle 1 such that the vehicle can follow the determined historic trail T1 . Hereby safer drive is facilitated in that the vehicle 1 will follow a trail which is drivable as the vehicle 2 has been driving along the trajectory corresponding to the historic trail T1 . Hereby a proper trajectory is provided for the vehicle to follow so that the vehicle 1 will be assisted in keeping the lane of the vehicle 2 ahead without the need for lane keep assistance function or as a redundancy to a lane keep assistance function if it is malfunctioning due to road marks or the like not being visible/detectable. The vehicle will be assisted in driving independent of whether map data exists/is available/if false and/or whether it is possible to detect road marks.

The system comprises means for continuously determining whether the vehicle is following the thus determined historic trail T1 . The system I is configured to provide a warning to the operator of the vehicle 1 if driving of the vehicle deviates from said determined historic trail to a predetermined extent.

Fig. 2b schematically illustrates a road with two lanes L1 , L2, a first lane L1 in which a vehicle 1 is travelling and a second lane L2 adjacent to the first lane L1 . The lanes L1 , L2 have been redirected and formed into temporary lanes L1 a, L2a at a certain position due to a road construction C ahead, the temporary lanes L1 a, L2a bypassing the construction work.

A vehicle 2 is travelling in the lane L1 a ahead of the vehicle 1 .

In accordance with the example in fig. 2a the vehicle 1 comprises a system I for controlling driving of a vehicle along a road. The system I comprises means for a vehicle 2 along the road ahead of said vehicle 1 . The system I comprises a detector unit D for detecting vehicles ahead of the vehicle 1 so as to track the vehicle 2 ahead of said vehicle 1 . The system I comprises means for determining a historic trail of the vehicle being tracked. The means for determining a historic trail of the vehicle being tracked comprises the detector unit D.

In the example in fig. 2b the vehicle 1 is tracking the vehicle 2 in the lane L1 a bypassing the road construction C. By means of the system I the vehicle 1 is determining a historic trail T2 of the vehicle 2.

According to an embodiment of the system I the means for determining a historic trail T2 comprises means for detecting the vehicle being tracked so as to obtain waypoints WP of earlier positions of the tracked vehicle 2. The detector unit D is comprised in the means for detecting the vehicle being tracked so as to obtain said waypoints WP of earlier positions of the tracked vehicle 2. The historic trail T2 of the tracked vehicle 2 is then created by means of the waypoints WP. The waypoints WP according to an embodiment essentially correspond to at least the width of the vehicle 2.

The vehicle 1 is following a thus determined historic trail T1 during driving of the vehicle 1 . As the historic trail T1 of the tracked vehicle 2 is running in the lane L1 a bypassing the road construction C, the vehicle 1 following the historic trail T2 will bypass the road construction C.

According to a variant the system I is controlling driving of the vehicle based upon that determined historic trail T2 as the vehicle 1 is following the thus determined historic trail T2. Controlling driving of the vehicle based upon said determined historic trail T2 comprises keeping the vehicle on the thus determined historic trail T2.

Fig. 3 schematically illustrates a system I for controlling driving of a vehicle along a road according to an embodiment of the present invention. The system I comprises an electronic control unit 100.

The system I comprises means 1 10 for tracking a vehicle along the road ahead of said vehicle. The means 1 10 for tracking a vehicle along the road ahead of said vehicle may comprise any suitable detecting means, i.e. any suitable detector unit. The means 1 10 for tracking a vehicle along the road ahead of said vehicle comprises according to an embodiment one or more camera units. The one or more camera units comprise according to an embodiment an IR-camera unit. The means 1 10 for tracking a vehicle along the road ahead of said vehicle comprises according to an embodiment one or more laser scanner units. The means 1 10 for tracking a vehicle along the road ahead of said vehicle comprises according to an embodiment one or more radar units. The system I comprises means 120 for determining a historic trail of the vehicle being tracked. The means 120 for determining a historic trail of the vehicle being tracked comprises according to an embodiment the means 1 10 for tracking a vehicle along the road ahead of said vehicle. The means 120 for determining a historic trail of the vehicle being tracked comprises thus one or more camera units and/or one or more laser scanner units and/or one or more radar units.

The means 120 for determining a historic trail comprises means 122 for detecting the vehicle being tracked so as to obtain waypoints of earlier positions of the tracked vehicle. The means 122 for detecting the vehicle being tracked so as to obtain waypoints of earlier positions of the tracked vehicle comprises thus one or more camera units and/or one or more laser scanner units and/or one or more radar units.

The means 120 for determining a historic trail comprises means 124 for creating the historic trail of said tracked vehicle based upon said waypoints. The system I comprises means 130 for determining the speed of the vehicle. The means 130 for determining the speed of the vehicle comprises according to an embodiment the speedometer of the vehicle.

The system I comprises means 140 for following a thus determined historic trail during driving of the vehicle. The means 140 for following a thus determined historic trail during driving of the vehicle comprises means 142 for controlling driving of the vehicle based upon said determined historic trail.

The means 142 for controlling driving of the vehicle based upon said determined historic trail comprises means 142a for keeping the vehicle on the thus determined historic trail.

The means 142 for controlling driving of the vehicle based upon said determined historic trail comprises means 142b for adapting the speed of the vehicle so as to keep the vehicle within the development of the thus determined historic trail and thus adapting at least to a certain extent to the speed of the vehicle being tracked when following the determined historic trail.

The system I comprises means 150 for continuously determining whether the vehicle is following the thus determined historic trail. The means 150 for continuously determining whether the vehicle is following the thus determined historic trail comprises means for comparing the position of the vehicle with the position of the determined historic trail. The means 150 may be comprised in the electronic control unit.

The system I comprises means 160 for providing a warning to the operator of the vehicle if driving of the vehicle deviates from said determined historic trail to a predetermined extent.

The means 160 for providing a warning to the operator of the vehicle comprises visual means for visually presenting the warning comprising a display unit or the like and/or acoustic means for audibly presenting the warning comprising a voice message, an alarm or the like and/or tactile means for tactile presentation of the warning such as vibrations of steering wheel or the like.

The system I may be provided with other functions for assisting driving such as a so called lane keep assistance function. Thus, according to an embodiment the system I comprises means 170 for detecting the trajectory of the lane of the road along which the vehicle is travelling. The means 170 for detecting the trajectory of the lane of the road along which the vehicle is travelling is configured to detect the trajectory of the road.

The means 170 for detecting the trajectory of the lane of the road along which the vehicle is travelling may be any suitable detecting means. The means 170 for detecting the trajectory of the lane of the road along which the vehicle is travelling comprises according to an embodiment one or more camera units. The one or more camera units comprise according to an embodiment an IR- camera unit. The means 170 for detecting the trajectory of the lane of the road along which the vehicle is travelling comprises according to an embodiment one or more laser scanner units. The means 170 for detecting the trajectory of the lane of the road along which the vehicle is travelling comprises according to an embodiment one or more radar units.

The means 170 for detecting the trajectory of the lane of the road along which the vehicle is travelling comprises detecting characteristics along the road.

The characteristics along the road comprise according to an embodiment road marks defining the lane comprising solid lines and dashed lines. The characteristics along the road comprise according to an embodiment crash barriers. The characteristics along the road comprise according to an embodiment a road side.

The means 170 is configured to deactivate if detection of the trajectory of the lane is not functioning on a desired level, i.e. if it is not possible to provide a reliable detection of the trajectory of the lane of the road.

In such a case the means 140 for following a thus determined historic trail during driving of the vehicle is used as a backup.

According to an embodiment the system does not comprise the means 170, in which case the means 140 for following a thus determined historic trail during driving of the vehicle is used for controlling the driving of the vehicle. According to an embodiment the system I comprises means 1 80 for determining the trajectory of the road along which the vehicle is travelling based on a determined current position of the vehicle and extracted map information of the extension of the road along which the vehicle is travelling. The means 1 80 for determining the trajectory of the road along which the vehicle is travelling based on a determined current position of the vehicle and extracted map information of the extension of the road along which the vehicle is travelling comprises according to an embodiment a map information unit 182 comprising map data comprising information about the trajectory of the road on which the vehicle is travelling comprising curves, road exits, road entrances and the surroundings of the road.

The means 1 80 for determining the trajectory of the road along which the vehicle is travelling based on a determined current position of the vehicle and extracted map information of the extension of the road along which the vehicle is travelling comprises according to an embodiment means 1 84 for determining the position of the vehicle. The means 1 84 for determining the position of the vehicle comprises according to an embodiment a global positioning system, GPS, for continuously determining the position of the vehicle along the road on which it is travelling. By means of the map information unit 1 82 and the means 184 for determining the position of the vehicle it is thus facilitated to continuously identifying the position of the vehicle and the trajectory of the road along which the vehicle is travelling including the trajectory of the road along which the vehicle is travelling a certain distance ahead of the vehicle. According to an embodiment the system does not comprise the means 180, in which case the means 140 for following a thus determined historic trail during driving of the vehicle is used for controlling the driving of the vehicle.

According to an optional embodiment the system I comprises means 1 90 for comparing the determined historic trail determined with the means 120 with the trajectory determined with the means 180, i.e. by means of extracted map information and vehicle position. The means 1 90 for comparing the determined historic trail with the trajectory determined by means of extracted map information and vehicle position comprises according to an embodiment an electronic control unit. The means 1 90 for comparing the determined historic trail with the trajectory determined by means of extracted map information and vehicle position comprises according to an embodiment the electronic control unit 100.

The means 190 for comparing comprises determining if and to what extent the determined historic trail differs from the trajectory determined by means of extracted map information and vehicle position. Here the determined historic trail may function as a backup if the trajectory determined by means of extracted map information and vehicle position is incorrect due to e.g. road construction or a new/updated road extension. Thus, if there is a certain difference in said comparison the determined historic trail is according to an embodiment the basis for controlling driving of the vehicle.

The electronic control unit 100 is operably connected to the means 1 10 for tracking a vehicle along the road ahead of said vehicle via a link 10. The electronic control unit 100 is via the link 10 arranged to receive a signal from said means 1 10 representing data for tracked vehicles ahead of said vehicle.

The electronic control unit 100 is operably connected to the means 120 for determining a historic trail of the vehicle being tracked via a link 20a. The electronic control unit 100 is via the link 20a arranged to send a signal to said means 120 representing data for tracked vehicles ahead of said vehicle. The electronic control unit 100 is operably connected to the means 120 for determining a historic trail of the vehicle being tracked via a link 20b. The electronic control unit 100 is via the link 20b arranged to receive a signal from said means 120 representing data for historic trail of the vehicle being tracked. The electronic control unit 100 is operably connected to the means 122 for detecting the vehicle being tracked so as to obtain waypoints of earlier positions of the tracked vehicle via a link 22. The electronic control unit 100 is via the link 22 arranged to receive a signal from said means 122 representing data for waypoints of earlier positions of the tracked vehicle.

The electronic control unit 100 is operably connected to the means 124 for creating the historic trail of said tracked vehicle based upon said waypoints via a link 24a. The electronic control unit 100 is via the link 24a arranged to send a signal to said means 124 representing data for waypoints of earlier positions of the tracked vehicle.

The electronic control unit 100 is operably connected to the means 124 for creating the historic trail of said tracked vehicle based upon said waypoints via a link 24b. The electronic control unit 100 is via the link 24b arranged to receive a signal from said means 124 representing data for historic trail of the tracked vehicle.

The electronic control unit 100 is operably connected to the means 130 for determining the speed of the vehicle via a link 30. The electronic control unit 100 is via the link 30 arranged to receive a signal from said means 130 representing data for speed of the vehicle. The electronic control unit 100 is operably connected to the means 140 for following a thus determined historic trail during driving of the vehicle via a link 40. The electronic control unit 100 is via the link 40 arranged to send a signal to said means 140 representing data for determined historic trail.

The electronic control unit 100 is operably connected to the means 142 for controlling driving of the vehicle based upon said determined historic trail via a link 42. The electronic control unit 100 is via the link 42 arranged to receive a signal from said means 142 representing data for control of driving comprising data for keeping the vehicle on the thus determined historic trail and data for adapting the speed of the vehicle so as to keep the vehicle within the development of the thus determined historic trail.

The electronic control unit 100 is operably connected to the means 150 for continuously determining whether the vehicle is following the thus determined historic trail via a link 50. The electronic control unit 100 is via the link 50 arranged to receive a signal from said means 150 representing data for position of the vehicle relative to the position of the determined historic trail.

The electronic control unit 100 is operably connected to the means 160 for providing a warning to the operator of the vehicle if driving of the vehicle deviates from said determined historic trail to a predetermined extent via a link 60a. The electronic control unit 100 is via the link 60a arranged to send a signal to said means 1 60 representing comparison data for comparison of the position of the vehicle with the position of the determined historic trail.

The electronic control unit 100 is operably connected to the means 160 for providing a warning to the operator of the vehicle if driving of the vehicle deviates from said determined historic trail to a predetermined extent via a link 60b. The electronic control unit 100 is via the link 60b arranged to receive a signal to from said means 160 representing data for warning to the operator of the vehicle if the vehicle deviates from the determined historic trail to a predetermined extent.

The electronic control unit 100 is operably connected to the means 1 80 for determining the trajectory of the road along which the vehicle is travelling based on a determined current position of the vehicle and extracted map information of the extension of the road along which the vehicle is travelling via a link 80. The electronic control unit 100 is via the link 80 arranged to receive a signal from said means 180 representing data for trajectory determined based on a determined current position of the vehicle and extracted map information. The electronic control unit 100 is operably connected to the means 1 70 for detecting the trajectory of the lane of the road along which the vehicle is travelling via a link 70a. The electronic control unit 100 is via the link 70a arranged to receive a signal from said means 1 70 representing data for detected trajectory of the lane of the road along which the vehicle is travelling comprising data of the trajectory of the road comprising information about the quality of the data, i.e. whether it was possible to detect the trajectory and if so if the detected trajectory is reliable.

The electronic control unit 100 is operably connected to the means 1 70 for detecting the trajectory of the lane of the road along which the vehicle is travelling via a link 70b. The electronic control unit 100 is via the link 70b arranged to send a signal to said means 170 representing data for deactivation of the means 170 due to data for trajectory not being reliable.

The electronic control unit 100 is operably connected to the map information unit 1 82 comprising map data comprising information about the trajectory of the road on which the vehicle is travelling via a link 82. The electronic control unit 100 is via the link 82 arranged to receive a signal from said map information unit 182 representing map data comprising information about the trajectory of the road on which the vehicle is travelling. The electronic control unit 100 is operably connected to the means 184 for determining the position of the vehicle via a link 84. The electronic control unit 100 is via the link 84 arranged to receive a signal from said means 1 84 representing data for position of the vehicle.

The electronic control unit 100 is operably connected to the means 190 for comparing the determined historic trail with the trajectory determined by means of extracted map information and vehicle position via a link 90a. The electronic control unit 100 is via the link 90a arranged to send a signal to said means 190 representing data for determined historic trail. The electronic control unit 100 is operably connected to the means 190 for comparing the determined historic trail with the trajectory determined by means of extracted map information and vehicle position via a link 90b. The electronic control unit 100 is via the link 90b arranged to send a signal to said means 190 representing data for extracted map information and vehicle position.

The electronic control unit 100 is operably connected to the means 190 for comparing the determined historic trail with the trajectory determined by means of extracted map information and vehicle position via a link 90c. The electronic control unit 100 is via the link 90c arranged to receive a signal from said means 190 representing comparison data for comparison of the determined historic trail with the trajectory determined by means of extracted map information and vehicle position.

Fig. 4 schematically illustrates a block diagram of a method for facilitating driving of a vehicle along a road according to an embodiment of the present invention.

According to the embodiment the method for facilitating driving of a vehicle along a road comprises a step S1 . In this step at least one vehicle are tracked along the road ahead of said vehicle. According to the embodiment the method for facilitating driving of a vehicle along a road comprises a step S2. In this step a historic trail of the vehicle being tracked is determined.

According to the embodiment the method for facilitating driving of a vehicle along a road comprises a step S3. In this step a determined historic trail is taken into consideration during driving of the vehicle.

In Fig. 6 a flow chart illustrating some procedural steps that can be performed when determining a track to follow/ use as steering input in accordance with one exemplary embodiment. Some steps can be omitted and or performed in another order. The steps can be performed using a suitable processor such as the control unit 100 described above. In the procedure of Fig. 6 the steps 603 - 615 are preferably performed for each vehicle being detected. First in a step 601 the trail of the own vehicle is continuously determined. Then, in a step 603 the trail for at least one and preferably each detected vehicle in front of the own vehicle is determined. Next, in a step 605, the historic trail of the own vehicle is compared to the historic trail of the detected vehicle. It can then be checked if the own vehicle is following the detected vehicles trail for some time and/or distance compared to some pre-set threshold value, step 607. If the detected vehicle does not follow the trail of the detected vehicle for a long enough distance or time the detected vehicle can be determined to not be a candidate in a step 613 and is, at least for the time being, discarded from the set of candidate vehicles to follow the historic trail of. In accordance with some embodiments it can be checked if lane information from an imaging device such as a camera is available, step 609. In other words it is detected if the vehicle can obtain information regarding how the lanes are formed based on data from an imaging device (camera, sensor or the like). If it is detected in a step 61 1 that the detected vehicle leaves the lane the detected vehicle is also determined to not be a candidate in step 613. In accordance with some embodiments it can also be checked if the detected vehicle is a member of a platoon in which the own vehicle participates. This can take place in a step 615 for example by a vehicle to vehicle communication (V2V communication). Based on one or more of the above determinations one of the detected vehicles, in particular one of the detected vehicles not being discarded in step 613 is selected as the vehicle, the trail of which is to be followed. In case the own vehicle is a member of a platoon only members of the platoon are eligible to be selected in a step 617, else the detected vehicle that best matches a set of pre-defined criteria is selected as the vehicle to follow in a step 619 . When a vehicle has been selected the selected vehicle and in particular the trail of the selected vehicle can be used as information when determining the lane that the own vehicle is following in a step 621 . In other words the steering of the own vehicle can be controlled, at least to some extent based on the trail of the selected vehicle. In particular the steering can be controlled for an autonomous vehicle or a vehicle driven in a mode with steering aid. The trail of the selected vehicle can then be used instead of or as a supplement to lane markings. This can be useful for example when there are no visible lane markings, the visible range of road markings is insufficient for lateral control of the own vehicle or if there is an inconsistency in the road/lane markings.

Hereby safer drive is facilitated in that the vehicle will follow a trail which is drivable as the tracked vehicle has been driving along the trajectory corresponding to the historic trail. Hereby a proper trajectory is provided for the vehicle to follow so that the vehicle will be assisted in keeping the lane of the tracked vehicle without the need for lane keep assistance function or as a redundancy to a lane keep assistance function if it is malfunctioning due to road marks or the like not being visible/detectable. The vehicle will be assisted in driving independent of whether map data exists/is available/if false and/or whether it is possible to detect road marks. The thus determined historic trail may thus be used as a redundancy to map data and/or trajectory of the road obtained from road marks. The thus determined historic trail may be used where map data has not been updated, for example if the road has been changed by adding/changing lanes, adding a roundabout or the like, it he map data is temporarily wrong due to e.g. construction work or temporary obstacle or the like.

The thus determined historic trail may be used as a basis for controlling the vehicle along the road when the vehicle is driving in the lane corresponding to the historic trail, said control of the vehicle comprising keeping the vehicle on the historic trail. This thus provides for efficient driver assistance and facilitates efficient autonomous drive. This provides for efficient positioning of the vehicle on the road during driving along the road. According to an embodiment of the method the step of following a thus determined historic trail during driving of the vehicle comprises controlling driving of the vehicle based upon said determined historic trail. By thus controlling driving based upon the historic trail safety is improved. The control of the vehicle may hereby be handled automatically based upon the historic trail.

According to an embodiment of the method the step of controlling driving of the vehicle based upon said determined historic trail comprises keeping the vehicle on the thus determined historic trail. Hereby safety of driving the vehicle is improved. Thus, an efficient and reliable way of keeping the vehicle on a lane where another vehicle has driven is hereby obtained.

According to an embodiment the method further comprises the steps of: continuously determining whether the vehicle is following the thus determined historic trail; and providing a warning to the operator of the vehicle if driving of the vehicle deviates from said determined historic trail to a predetermined extent. This further improves safety in that the operator/driver may take actions based upon the warning. The driver will hereby be informed if the vehicle deviates from the historic trail and may thus avoid an accident due to such deviation. According to an embodiment of the method the step of determining a historic trail comprises detecting the vehicle being tracked so as to obtain waypoints of earlier positions of the tracked vehicle; based upon said waypoints creating the historic trail of said tracked vehicle. Hereby an easy and efficient way of obtaining the historic trail based upon a vehicle ahead is obtained. With reference to figure 5, a diagram of an apparatus 500 is shown. The control unit 100 described with reference to fig. 3 may according to an embodiment comprise apparatus 500. Apparatus 500 comprises a non-volatile memory 520, a data processing device 510 and a read/write memory 550. Non-volatile memory 520 has a first memory portion 530 wherein a computer program, such as an operating system, is stored for controlling the function of apparatus 500. Further, apparatus 500 comprises a bus controller, a serial communication port, l/O-means, an A/D-converter, a time date entry and transmission unit, an event counter and an interrupt controller (not shown). Non-volatile memory 520 also has a second memory portion 540.

A computer program P is provided comprising routines for controlling driving of a vehicle along a road according to an embodiment of the present invention. The program P comprises routines for tracking a vehicle along the road ahead of said vehicle. The program P comprises routines for determining a historic trail of the vehicle being tracked. The program P comprises routines for following a thus determined historic trail during driving of the vehicle. The program P comprises routines for controlling driving of the vehicle based upon said determined historic trail. The program P comprises routines for keeping the vehicle on the thus determined historic trail. The program P comprises routines for continuously determining whether the vehicle is following the thus determined historic trail. The program P comprises routines for providing a warning to the operator of the vehicle if driving of the vehicle deviates from said determined historic trail to a predetermined extent. The program P comprises routines for detecting the vehicle being tracked so as to obtain waypoints of earlier positions of the tracked vehicle. The program P comprises routines for creating the historic trail of said tracked vehicle based upon said waypoints. The computer program P may be stored in an executable manner or in a compressed condition in a separate memory 560 and/or in read/write memory 550. When it is stated that data processing device 510 performs a certain function it should be understood that data processing device 510 performs a certain part of the program which is stored in separate memory 560, or a certain part of the program which is stored in read/write memory 550.

Data processing device 510 may communicate with a data communications port 599 by means of a data bus 515. Non-volatile memory 520 is adapted for communication with data processing device 510 via a data bus 512. Separate memory 560 is adapted for communication with data processing device 510 via a data bus 51 1 . Read/write memory 550 is adapted for communication with data processing device 510 via a data bus 514. To the data communications port 599 e.g. the links connected to the control units 100 may be connected.

When data is received on data port 599 it is temporarily stored in second memory portion 540. When the received input data has been temporarily stored, data processing device 510 is set up to perform execution of code in a manner described above. The signals received on data port 599 can be used by apparatus 500 for tracking a vehicle along the road ahead of said vehicle. The signals received on data port 599 can be used by apparatus 500 for determining a historic trail of the vehicle being tracked. The signals received on data port 599 can be used by apparatus 500 for following a thus determined historic trail during driving of the vehicle. The signals received on data port 599 can be used by apparatus 500 for controlling driving of the vehicle based upon said determined historic trail. The signals received on data port 599 can be used by apparatus 500 for keeping the vehicle on the thus determined historic trail. The signals received on data port 599 can be used by apparatus 500 for continuously determining whether the vehicle is following the thus determined historic trail. The signals received on data port 599 can be used by apparatus 500 for providing a warning to the operator of the vehicle if driving of the vehicle deviates from said determined historic trail to a predetermined extent. The signals received on data port 599 can be used by apparatus 500 for detecting the vehicle being tracked so as to obtain waypoints of earlier positions of the tracked vehicle. The signals received on data port 599 can be used by apparatus 500 for creating the historic trail of said tracked vehicle based upon said waypoints.

Parts of the methods described herein can be performed by apparatus 500 by means of data processing device 510 running the program stored in separate memory 560 or read/write memory 550. When apparatus 500 runs the program, parts of the methods described herein are executed.

The foregoing description of the preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated.