Assistance system for a road vehicle

Abstract

The invention relates to an assistance system (1) for a road vehicle (2), which can be used on a road (3) having one or more lanes (4). The assistance system comprises a positioning system (7) for determining the lateral position of the road vehicle on the road (3). According to the invention, the positioning system has an electrical signal line (9) arranged along the road (3), a signal generator (12) for generating an electrical signal and feeding it to the signal line (9), whereby an electrical current can be generated in the signal line (9), a sensor device on the vehicle side for detecting the field strength and / or field direction of an electromagnetic field (H) formed around the signal line (9) as a result of the generated electrical current, and an analysis unit (14) on the vehicle side, which is designed to determine the lateral relative position (Y) of the road vehicle (2) relative to the signal line (9) from the measured field strength and / or field direction. An assistance system (1) having a more reliable positioning system (7) is thereby provided.

Description

TECHNICAL FIELD

[0001] The invention relates to an assistance system for a road vehicle which can be used on a road having one or more lanes, comprising a positioning system for determining the lateral position of the road vehicle on the road. BACKGROUND

[0002] Determining the lateral position of a road vehicle, in particular a passenger car or a truck, is essential for many assistance systems. It is essential for lane-keeping systems and for steering intervention systems of semi- or fully-automated road vehicles to know in which lane of a multi-lane road or in which position within a lane the road vehicle is located.

[0003] Known positioning systems have a vehicle-side device, in particular a camera or other optical scanning device, for optically detecting directional lines of the lane course. From the document DE 103 16 413 A1 a method and a device for directional control of a vehicle are known, in which lateral lane boundary markings are detected as directional lines and analyzed in order to correct the movement direction of the vehicle. In contrast, the document DE 10 2006 061 425 A1 teaches to orientate in a formed track within a lane. However, camera-based positioning systems are unreliable or fail completely when two directional lines cannot be detected due to worn road markings, absence of tracks or due to adverse weather conditions, such as heavy rain or fog, the road being covered with snow or difficult lighting conditions, such as when driving at night or when the sun has set. SUMMARY

[0004] It is therefore the object of the present invention to provide an assistance system of the aforementioned type with a more reliable positioning system.

[0005] The technical problem is solved by an assistance system for a road vehicle according to the application. The positioning system of the assistance system accordingly has an electrical signal line which is arranged along the road. The signal line can be designed as single-pole or multi-pole and can be suspended at the side or above the road, for example on an antenna mast with lateral support means. Furthermore, the positioning system has a signal generator for generating an electrical signal and feeding it to the signal line, whereby an electrical current can be generated in the signal line. The signal is preferably a low-frequency signal, the frequency of which is in the range from 1 kHz to 10 MHz. Furthermore, the positioning system has a sensor device on the vehicle side, which is used to detect the field strength and / or the field direction of the electromagnetic field which is formed around the signal line as a result of the generated electrical current. The sensor device can for example have one or more sensors for detecting the magnetic field component. Furthermore, the positioning system has an analysis unit on the vehicle side, which is designed to determine the lateral position of the road vehicle relative to the signal line from the detected field strength and / or field direction. An alternating magnetic field which is cylindrically symmetrical over the entire length of the conductor through which the current flows is formed, the field strength of which decreases with increasing distance from the conductor, and the field direction of which depends on the current direction through the conductor according to the so-called left-hand rule. For a double-pole or multi-pole signal line, the magnetic fields of the signal line add up to one another depending on the distance between the conductor poles and the current direction through the conductor poles. It is thereby possible to determine the position of the magnetic field sensor relative to the signal line from the measured field strength and field direction at the magnetic field sensor or at a plurality of magnetic field sensors. From the known mounting position of the magnetic field sensor on the road vehicle, the lateral position of the magnetic field sensor relative to the signal line can be determined. This position determination is independent of weather conditions, lighting conditions and snowfall and is therefore more reliable than a camera-based positioning.

[0006] In an advantageous embodiment of the assistance system according to the application, the signal line is arranged above the road along the lane centre line of the lane or at a defined lateral distance from the lane centre line. The lane centre line is to be understood here as a plane which rises perpendicularly to the lane surface and which contains a line which extends centrally between the left lane boundary line and the right lane boundary line. The lane centre line is for example flat for the case of a straight lane extension and cylindrical for the case of a lane extension in the shape of a circular arc. If the signal line is single-pole and extends in the lane centre line, or if the signal line is double-pole and the conductor poles of the signal line extend symmetrically relative to the lane centre line, the lane centre line becomes an orientation line relative to which the lateral position of the road vehicle is determined. If the signal line extends at a defined lateral distance from the lane centre line which can vary depending on the longitudinal position, the corresponding lateral distance which corresponds to the respective longitudinal position can be stored in a database which is accessed by the analysis unit when determining the lateral relative position of the road vehicle.

[0007] In a further advantageous embodiment of the assistance system according to the application, the signal line is designed bipolarly and the signal generator is designed to generate a differential electrical signal and to feed the differential electrical signal into both conductor poles of the signal line. For the case of a bipolar signal line, it is advantageous to feed a differential signal into the conductor poles, since the electromagnetic field formed thereby is particularly suitable for an exact position determination. However, the positioning system can in principle also be used in a unipolar signal line, in which case the ground is fed.

[0008] In a further advantageous embodiment of the assistance system according to the application, the sensor device has a plurality of magnetic field sensors which are arranged laterally offset on the roof of the road vehicle. It is advantageous for the positioning to use a plurality of locally offset magnetic field sensors on the vehicle, which are arranged on the roof, for example, on the right and on the left.

[0009] In a further advantageous embodiment of the assistance system according to the application, the analysis unit is designed to determine, from the determined relative position, the lane of the road vehicle which is currently used from a plurality of lanes of the road. From the number and width of the lanes known for the direction of travel of the road, the lane in which the road vehicle is currently traveling can be inferred with the aid of the determined relative position. The knowledge of the lane currently used by the road vehicle is in turn a prerequisite for a plurality of lane selection applications of the assistance system.

[0010] In a further advantageous embodiment of the assistance system according to the application, the analysis unit is designed to determine, from the determined relative position, the current lateral offset of the road vehicle relative to the lane center line of the lane used. The knowledge of the lateral offset of the road vehicle relative to the lane center line of the lane used can be used, for example, by the assistance system for directional control, lane keeping and automatic operation of the road vehicle.

[0011] In a further advantageous embodiment, the assistance system according to the application comprises a vehicle-side output unit for outputting the lane used and / or the lateral offset relative to the lane center line of the lane used visually and / or acoustically to the driver of the road vehicle. The lane used can be displayed to the driver, for example, on a screen of a vehicle device, for example a navigation device. If the lateral offset relative to the lane center line exceeds a pre-set threshold value, a warning tone can be emitted to the driver, for example.

[0012] In a further advantageous embodiment of the assistance system according to the application, the signal generator is designed to modulate data representing traffic information for a specific longitudinal position and a specific lane onto the electrical signal, wherein the output unit is designed to output the traffic information for a specific longitudinal position and a specific lane to the driver of the road vehicle depending on the current longitudinal position and the currently used lane of the road vehicle. The electrical signal can comprise a carrier signal onto which the data are modulated by known methods of communication technology. The modulated data represent traffic information for the current specific longitudinal position of the road vehicle, for example a speed limit, a road toll, a navigation instruction or the presence of a contact line for the supply of energy by means of current collectors on both sides of the vehicle, or traffic information for the currently used specific lane of the road vehicle, for example the imminent cancellation or closure of a lane due to a construction site or an accident.

[0013] In a further advantageous embodiment, the assistance system according to the application comprises a steering intervention system on the vehicle side for automatically guiding the road vehicle within the used lane, the current determined lateral offset of the road vehicle relative to the lane center line being able to be input into the steering intervention system in order to determine a steering angle change. In order to keep the road vehicle within a predetermined value of the lateral offset relative to the lane center line, the current offset is continuously determined and input as an actual value into the steering intervention system. The steering intervention system can thereby determine the required steering angle change in order to guide and keep the road vehicle in the lane.

[0014] In a further advantageous embodiment of the assistance system according to the application, the signal line consists of a contact line designed as a forward conductor and a return conductor of a bipolar overhead conductor arrangement for the supply of energy to the road vehicle, wherein the contact line can be contacted with a current collector on the vehicle side in order to feed in energy. The assistance system according to the application is therefore particularly suitable for road vehicles having a current collector which can be in sliding contact with the contact line of an overhead conductor arrangement designed as a signal line in order to supply energy. From the point of view of maintaining continuous contact with the contact line of the overhead conductor arrangement, the necessary automated directional control of the road vehicle in an electrified lane is particularly advantageous for the continuous supply of energy to an electric or hybrid vehicle. The required lateral positioning can be achieved without the need for additional infrastructure beyond the installation of the overhead conductor arrangement. BRIEF DESCRIPTION OF DRAWINGS

[0015] Further features and advantages of the present application result from the following description of two specific embodiments according to the drawings, in which:

[0016] Figure 1 a top view of a first embodiment of an assistance system according to the application having a unipolar signal line is shown,

[0017] Figure 2 A schematic top view of a second exemplary embodiment of an auxiliary system according to the invention having a bipolar signal line is shown. DETAILED DESCRIPTION

[0018] according to Figure 1 and Figure 2 The assistance system 1 according to the invention is used to assist the semi-automatic or automatic operation of a road vehicle 2, which is operated on a single-lane or multi-lane road 3, which in the exemplary embodiment shown is operated on a three-lane highway with a left lane, a middle lane and a right lane for the shown direction of travel. The lanes 4 each have lateral lane boundary lines 5, a lane center line 6 extending centrally between the lane boundary lines and a lane width B, which is equal to the distance between the lane center lines of adjacent lanes 4. The assistance system 1 comprises a positioning system 7 for determining a lateral position Y of the road vehicle 2 on the road 3. On the road vehicle 2, for example, the longitudinal center axis 8 of the vehicle is used as a reference point for the lateral position Y of the road vehicle. The positioning system 7 has a plurality of positioning systems arranged along the road 3 according to Figure 1 The single-pole signal line 9 or according to Figure 2 A bipolar signal line 9 is arranged above the level of the road 2 via an antenna mast 10. Figure 1 , the signal line can extend on the side of the road 3, or according to Figure 2 The signal line can be extended along the lane center line 6 above the road 3 via a transverse support device 11 fixed to the antenna mast 10 . Figure 1 By way of example, a single-pole situation is shown, in which the signal line 9 is arranged at a defined lateral distance Y(X) from the lane center line 6, which may vary with the longitudinal position X on the lane 4. Figure 2 In the case of a bipolar configuration, the positive and negative conductor poles of the signal line 9 are arranged symmetrically with respect to the lane center line 6. The electrical signal generated by the signal generator 11 of the positioning system 7 is fed into the signal line 9 in the form of a low-frequency signal between 1 kHz and 100 MHz, thereby forming an electromagnetic field H generated by the current around one or more signal conductors. Figure 2 In the case of a bipolar signal line, a differential electrical signal can advantageously be fed into the conductor poles. A vehicle-side sensor arrangement consisting of one or more spatially distributed magnetic field sensors 13 is arranged, for example, on the roof of the road vehicle 2 on both sides of the vehicle longitudinal center axis 8. The sensor arrangement is designed to detect the field strength and / or field direction of an electromagnetic field.

[0019] The positioning system 7 also has an evaluation unit 14 on the vehicle side, which is designed to determine the lateral position Y of the road vehicle 2 relative to the signal line 9 from the detected field strength and / or field direction of the electromagnetic field H. On the basis of the lateral distance Y(X) and the lane width B, which are known and stored in the evaluation unit 14, the lane 4 currently used by the road vehicle 2 can be determined from the lateral position Y of the road vehicle 2 determined at the longitudinal position X of the road 3. Furthermore, the evaluation unit 14 is designed to determine the current lateral offset ΔY of the road vehicle 2 relative to the lane center line 6 of the lane 4 used from the determined relative position Y.

[0020] According to Figure 2 the assistance system 1 comprises an output unit 15 on the vehicle side for visually and / or acoustically outputting the lane 4 used and / or the lateral offset ΔY relative to the lane center line 6 of the lane 4 used to the driver of the road vehicle 2. The output unit is also designed to output traffic information V about a specific longitudinal position and a specific lane to the driver of the road vehicle 2 from the current longitudinal position X and the lane 4 currently used by the road vehicle 2. To this end, the signal generator 12 is designed to modulate data representing the traffic information V about a specific longitudinal position and a specific lane onto the electrical signal, for example a position of an imminent closure or an obstacle on the lane 4 used or a current speed limit.

[0021] Furthermore, according to Figure 2 the assistance system 1 comprises a steering intervention system 16 on the vehicle side for automatically guiding the road vehicle 2 within the lane 4 used. The currently determined lateral offset ΔY of the road vehicle 2 relative to the lane center line 6 is input to the steering intervention system 16 in order to determine a steering angle change Δα.

[0022] Figure 2 The road vehicle 2 of the illustrated embodiment has a current collector 17, which is in contact with a contact line 18 of a bipolar overhead conductor arrangement in order to feed in electrical energy. In order to feed energy to consumers, in particular drives, of the road vehicle 2 during travel, the current collector 17 is in electrically sliding contact with the contact line 18. The signal line 9 of the assistance system 1 according to the application is formed by the contact line 18 of the overhead conductor arrangement, which is designed as a departure conductor and a return conductor.

Claims

1. An assistance system (1) for a road vehicle (2) capable of being used on a road (3) having one or more lanes (4), the assistance system comprising - a positioning system (7) for determining the lateral position of a road vehicle on said road (3), It is characterized by: The positioning system has: an electrical signal line (9) arranged along the road (3), wherein the signal line (9) is arranged above the road (3) along a lane centerline (6) of the lane (4) or at a defined lateral distance (Y(X)) from the lane centerline (6), a signal generator (12) for generating an electrical signal and feeding the electrical signal to the signal line (9), thereby enabling a current to be generated in the signal line (9), - a sensor device on the vehicle side for detecting the field strength and / or field direction of the electromagnetic field (H) formed around the signal line (9) due to the generated current, and - a vehicle-side evaluation unit (14), which is designed to - determining the relative position (Y) of the road vehicle (2) in the transverse direction relative to the signal line (9) based on the measured field strength and / or field direction, - determining the lane (4) currently used by the road vehicle (2) from a plurality of lanes (4) of the road (3) based on the determined relative position (Y), - determining a current lateral offset (ΔY) of the road vehicle (2) relative to a lane centerline (6) of the used lane (4) based on the determined relative position (Y).

2. The assistance system (1) according to claim 1, wherein The signal line (9) is bipolar in design, and the signal generator (12) is designed to generate a differential electrical signal and feed the differential electrical signal into the two conductor poles of the signal line (9).

3. The assistance system (1) according to claim 1 or 2, wherein: The sensor device has a plurality of magnetic field sensors (13) arranged laterally offset on the roof of the road vehicle (2).

4. The assistance system (1) according to claim 1 or 2, wherein: The assistance system comprises a vehicle-side output unit (15) for outputting the used lane (4) and / or the lateral offset (ΔY) relative to the lane centerline (6) of the used lane (4) to the driver of the road vehicle (2) visually and / or acoustically.

5. The assistance system (1) according to claim 4, - wherein the signal generator (12) is designed to modulate data representing traffic information (V) of a specific longitudinal position and a specific lane onto an electrical signal, - and among them, The output unit (15) is designed to output traffic information (V) about a specific longitudinal position and a specific lane to the driver of the road vehicle (2) based on the current longitudinal position (X) of the road vehicle (2) and the currently used lane (4).

6. The assistance system (1) according to claim 1 or 2, wherein: The assistance system comprises a vehicle-side steering intervention system (16) for automatically guiding the road vehicle (2) within the used lane (4), wherein a currently determined lateral offset (ΔY) of the road vehicle (2) relative to the lane centerline (6) can be input into the steering intervention system in order to determine a steering angle change (Δα).

7. The assistance system (1) according to claim 1 or 2, wherein: The signal line (9) consists of a contact wire (18) designed as a forward conductor and a return conductor of a bipolar overhead line system for supplying energy to a road vehicle (2), wherein the contact wire (18) can be contacted via a vehicle-side current collector (17) for feeding in energy.

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