ASSISTANCE SYSTEM FOR A ROAD VEHICLE

Description

[0001] The invention relates to an assistance system for a road vehicle usable on a roadway with one or more lanes, comprising a position determination system for determining a lateral position of the road vehicle on the roadway.

[0002] Determining the lateral position of a road vehicle, especially a passenger car or truck, is of central importance for many assistance systems. For both lane keeping systems and steering control systems of partially automated or autonomous road vehicles, it is crucial to know which lane of a multi-lane roadway or where within a lane the road vehicle is currently located.

[0003] DE 10 2011 076615 A1 discloses a non-rail-bound vehicle with a current collector for feeding electrical energy from an overhead line system having at least one contact wire. The current collector has at least one contact strip with a working range for contacting the at least one contact wire. Actuator means for adjusting the at least one contact strip are coupled to the current collector, wherein the at least one contact strip is aligned horizontally and adjustable transversely to a vehicle longitudinal axis. The position of the vehicle relative to the at least one contact wire is detected by sensors. A control device is connected to the sensors and the actuators and is designed to control the actuators depending on the vehicle position detected by the sensors such that the at least one contact strip maintains contact with the at least one contact wire within its working range.

[0004] Known positioning systems have vehicle-mounted devices, particularly video cameras or other optical scanning devices, for optically detecting orientation lines along a lane. For example, German Patent Application DE 103 16 413 A1 discloses a method and device for lane guidance of a vehicle, in which lateral lane markings are detected as orientation lines and evaluated to correct the vehicle's direction of travel. In contrast, German Patent Application DE 10 2006 061 425 A1 teaches orientation based on ruts that form within a lane.However, camera-based positioning systems are unreliable or fail completely when road markings are worn, ruts are missing, or both orientation lines cannot be detected due to difficult weather conditions such as heavy rain or fog, snow-covered roadways, or difficult lighting conditions such as glare during night driving or low sun.

[0005] The invention is therefore based on the object of providing an assistance system of the type mentioned above, whose position determination system is more reliable.

[0006] This problem is solved by a generic assistance system with the features specified in the characterizing part of patent claim 1. Accordingly, the position determination system of the assistance system has an electrical signal line arranged longitudinally along the roadway, wherein the signal line is arranged above the roadway at defined lateral distances from the lane center. The lane center of a lane is understood here to be a surface perpendicular to the road surface, which contains a line running centrally between a left and right lane boundary line. For example, the lane center is flat in the case of a straight lane, and cylindrical in the case of a circular lane.If the signal line runs at defined lateral distances from the lane center—which may vary depending on the longitudinal position—the lateral distances assigned to the respective longitudinal positions can be stored in a database, which the evaluation unit accesses when determining the lateral relative position of the road vehicle. The signal line can be single-pole or multi-pole and suspended laterally or above the roadway, for example, on masts with transverse support structures. Furthermore, it has a signal generator for generating and feeding an electrical signal into the signal line, thereby generating a current flow in the signal line. The signal is preferably a low-frequency signal with a frequency in the range of 1 kHz to 10 MHz.Furthermore, it has a vehicle-mounted sensor arrangement for detecting a field strength and / or a field direction of an electromagnetic field formed around the signal line due to the generated current flow. The sensor arrangement can, for example, have one or more sensors for detecting the magnetic field component. In addition, the position determination system has a vehicle-mounted evaluation unit designed to determine a lateral position of the road vehicle relative to the signal line from the detected field strength and / or field direction. A cylindrically symmetrical alternating magnetic field forms around a current-carrying conductor over its entire length. The field strength of this alternating magnetic field decreases with increasing distance from the conductor and the field direction of this alternating magnetic field depends on the current direction through the conductor according to the so-called left-hand rule.In two-pole or multi-pole signal lines, their magnetic fields overlap depending on the distance between the conductor poles and the direction of current through the conductor poles. From this, the relative position of the magnetic field sensor to the signal line can be determined based on the field strength and field direction measured at the location of the magnetic field sensor(s). From the known mounting positions of the magnetic field sensor(s) on the road vehicle, the lateral position of the sensor(s) relative to the signal line can be determined. The evaluation unit is also designed to determine, from the determined relative position, a lane currently being used by the road vehicle from among several lanes on the roadway. From the number and width of lanes known for a direction of travel on the roadway, the determined relative position can be used to determine the lane currently being used by the road vehicle.Knowledge of the lane currently used by a road vehicle is, in turn, a prerequisite for a variety of lane-selective applications of the assistance system. The evaluation unit is further configured to use the determined relative position to determine the current lateral offset of the road vehicle from the center of the lane in use. Knowledge of the current lateral offset of a road vehicle from the center of the lane in use can be used, for example, in assistance systems for lane guidance, lane keeping, and the autonomous operation of a road vehicle. This positioning method is independent of weather conditions, lighting conditions, and snow cover and is therefore more reliable than camera-based positioning methods.

[0007] In an advantageous embodiment of the assistance system according to the invention, the signal line is arranged above the roadway along the center of a lane. If the signal line is single-pole and runs in the center of the lane, or if it is double-pole and its conductor poles run symmetrically to the center of the lane, the center of the lane becomes the orientation line relative to which the lateral position of the road vehicle is determined.

[0008] In a further advantageous embodiment of the assistance system according to the invention, the signal line is bipolar, and the signal generator is designed to generate and feed a differential electrical signal into the two conductor poles of the signal line. With bipolar signal lines, it is advantageous to feed a differential signal into the conductor poles, as the resulting electromagnetic field is particularly well suited for precise position determination. In principle, however, the positioning system can also be used with single-pole signal lines; in this case, the signal is fed to ground.

[0009] In a further advantageous embodiment of the assistance system according to the invention, the sensor arrangement comprises a plurality of magnetic field sensors arranged laterally offset on a roof of the road vehicle. For position determination, it is advantageous if the vehicle is equipped with a plurality of spatially offset magnetic field sensors, which are arranged, for example, on the right and left sides of the vehicle roof.

[0010] In a further advantageous embodiment, the assistance system according to the invention comprises a vehicle-mounted output unit for visually and / or acoustically outputting the lane in use and / or the lateral offset from the center of the lane in use to a driver of the road vehicle. The lane in use can be displayed to the driver, for example, on a screen of an in-vehicle device, such as a navigation device. A warning tone can be emitted to the driver, for example, if the lateral offset from the center of the lane exceeds a preset threshold.

[0011] In a further advantageous embodiment of the assistance system according to the invention, the signal generator is designed to modulate data representing longitudinal position and lane-specific traffic information onto the electrical signal, wherein the output unit is designed to output longitudinal position and lane-specific traffic information to a 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 data is modulated using known communication technology methods.The modulated data represents traffic information that is specific to a current longitudinal position of the road vehicle - such as a speed limit, a road toll, a navigation instruction or the presence of contact wires for power supply via a vehicle-mounted pantograph - or that is specific to a currently used lane of the road vehicle - such as an impending cancellation or a lane closure due to construction or an accident.

[0012] In a further advantageous embodiment, the assistance system according to the invention comprises a vehicle-mounted steering control system for automatically guiding the road vehicle within the lane in use, to which the currently determined lateral offset of the road vehicle from the lane center can be fed to determine a steering angle change. In order to keep the road vehicle within a target value for the lateral offset from the lane center, the current offset is continuously determined and fed to the steering control system as an actual value. The steering control system can use this to determine the required steering angle change to guide and maintain the road vehicle in the lane.

[0013] In a further advantageous embodiment of the assistance system according to the invention, the signal line is formed by contact wires of a two-pole overhead line system designed as forward and return conductors for supplying power to the road vehicle, wherein the contact wires can be contacted by a vehicle-mounted pantograph for power supply. The assistance system according to the invention is thus particularly suitable for road vehicles with a pantograph that can be brought into sliding contact with the contact wires of an overhead line system designed as signal lines for power supply. A possibly automated track guidance system for such road vehicles in the electrified lane is particularly advantageous from the point of view of maintaining continuous contact with the contact wires of the overhead line system with regard to a continuous power supply to the electric or hybrid-electric vehicle drive.The lateral position determination required for this is then possible without any additional infrastructure installation beyond the overhead line system.

[0014] Further features and advantages of the invention will become apparent from the following description of two specific embodiments with reference to the drawings, in which FIG 1 shows a first exemplary embodiment of the assistance system according to the invention in plan view with a single-pole signal line, FIG 2 shows a second exemplary embodiment of the assistance system according to the invention in plan view with a two-pole signal line, are schematically illustrated.

[0015] According to FIG 1 and FIG 2 An assistance system 1 according to the invention serves to support the partially automated or autonomous operation of road vehicles 2, which are operated on a single-lane or multi-lane roadway 3 - in the illustrated embodiments on a three-lane motorway with a left, a middle and a left lane 4 for the illustrated direction of travel. The lanes 4 each have lateral lane boundary lines 5, a lane center 6 running centrally between them and a lane width B, which corresponds to the distance between the lane centers of adjacent lanes 3. The assistance system 1 comprises a position determination system 7 for determining a lateral position Y of a road vehicle 2 on the roadway 3. On the road vehicle 2, for example, a vehicle longitudinal center 8 serves as a reference point for its lateral position Y. The position determination system 7 has, arranged longitudinally to the roadway 3 according to FIG 1 a single-pole signal line 9 or according to FIG 2 a two-pole signal line 9, which is arranged on masts 10 above the level of the roadway 2. They can be FIG 1 side of lane 3 or according to FIG 2 run over cross-supporting devices 11 attached to masts 10 above the carriageway 3 along the center of a lane 6. FIG 1 shows, by way of example, the single-pole case in which the signal line 9 is arranged at defined lateral distances Y(X) from the lane center 6, possibly varying with the longitudinal position X on the carriageway 2. In the two-pole case according to FIG 2 The positive and negative conductor poles of the signal line 9 are arranged symmetrically to the lane center 6. An electrical signal in the form of a low-frequency signal between 1 kHz and 100 MHz, generated by a signal generator 11 of the position determination system 7, is fed into the signal line 9, whereby a current-flow-induced electromagnetic field H is formed around the signal conductor(s) 9. In the two-pole signal line according to FIG 2 A differential electrical signal can advantageously be fed into the conductor poles. A vehicle-mounted sensor arrangement comprising one or more magnetic field sensors 13, which are spatially distributed, for example, arranged on a roof of the road vehicle 2 on both sides of the vehicle's longitudinal centerline 8, is designed to detect a field strength and / or a field direction of the electromagnetic field.

[0016] The position determination system 7 further comprises a vehicle-side evaluation unit 14, which is designed to determine a 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. Based on the known lateral distances Y(X) and lane width B stored in the evaluation unit 14, a lane 4 currently used by the road vehicle 2 is determined from the determined lateral position Y of the road vehicle 2 at a longitudinal position X of the roadway 3. Furthermore, the evaluation unit 14 is designed to determine a current lateral offset ΔY of the road vehicle 2 from the lane center 8 of the lane 4 used from the determined relative position Y.

[0017] The assistance system 1 includes FIG 2 a vehicle-side output unit 15 for the visual and / or acoustic output of the used lane 4 and / or the lateral offset ΔY from a lane center 6 of the used lane 4 to a driver of the road vehicle 2. It is also designed to output longitudinal position- and lane-specific traffic information V to a driver of the road vehicle 2 depending on the current longitudinal position X and the currently used lane 4 of the road vehicle 2. For this purpose, the signal generator 12 is designed to modulate data representing longitudinal position- and lane-specific traffic information V onto the electrical signal, such as upcoming closures or disruptions on the currently used lane 4 or current speed restrictions.

[0018] Furthermore, the assistance system 1 includes FIG 2 a vehicle-side steering control system 16 for the automated guidance of the road vehicle 2 within the lane used 4. The currently determined lateral offset ΔY of the road vehicle 2 from the lane center 6 is fed to the steering influence system 16 to determine a steering angle change Δα.

[0019] The road vehicle 2 of the FIG 2 The illustrated embodiment has a current collector 17, which contacts the contact wires 18 of a two-pole overhead line system for supplying electrical energy. To supply energy to electrical consumers, in particular the drive, of the road vehicle 2 while driving, the current collector 17 is brought into electrical sliding contact with the contact wires 18. The signal lines 9 of the assistance system 1 according to the invention are formed by the contact wires 18 of the overhead line system, which are designed as forward and return conductors.

Claims

1. Assistance system (1) for a road vehicle (2) which can be used on a roadway (3) having one or more lanes (4), comprising - a position determination system (7) for determining a lateral position of the road vehicle on the roadway (3), wherein the position determination system (7) has: - an electrical signal line (9) arranged parallel to the roadway (3), wherein the signal line (9) is arranged above the roadway (3) at defined lateral distances (Y(X)) to a lane centre (6) of the or a lane (4) (6), - a signal generator (12) for generating and feeding an electrical signal into the signal line (9), as a result of which a current flow is generated in the signal line (9), - an on-vehicle sensor assembly for capturing a field strength and / or a field direction of an electromagnetic field (H) forming about the signal line (9) as a result of the current flow generated and - an on-vehicle evaluation unit (14), which is designed - to determine, from the captured field strength and / or field direction, a lateral relative position (Y) of the road vehicle (2) relative to the signal line (9), and - to determine, from the determined relative position (Y), the defined lateral distances (Y(X)) and a defined lane width (B) of a plurality of lanes (4) of the roadway (3), a lane (4) currently used by the road vehicle (2) and a current lateral offset (ΔY) of the road vehicle (2) from the lane centre (6) of the used lane (4).

2. Assistance system (1) according to claim 1, - wherein the signal line (9) is two-pole, and the signal generator (12) is designed for generating and feeding a differential electrical signal into the two conductor poles of the signal line (9).

3. Assistance system (1) according to one of claims 1 or 2, - wherein the sensor assembly has a plurality of magnetic field sensors (13) arranged laterally offset on a vehicle roof of the road vehicle (2).

4. Assistance system (1) according to one of claims 1 to 3, comprising - an on-vehicle output unit (15) for the visual and / or acoustic output of the used lane (4) and / or the lateral offset (ΔY) from a lane centre (6) of the used lane (4) to a driver of the road vehicle (2).

5. Assistance system (1) according to one of claims 1 to 4, - wherein the signal generator (12) is designed to modulate data representing longitudinal position- and lane-specific traffic information (V) to the electrical signal, and - wherein the output unit (15) is designed to output longitudinal position- and lane-specific traffic information (V) to a driver of the road vehicle (2) as a function of the current longitudinal position (X) and the currently used lane (4) of the road vehicle (2).

6. Assistance system (1) according to one of claims 1 to 5, comprising - an on-vehicle steering control system (16) for the automated guidance of the road vehicle (2) within the used lane (4), to which the currently determined lateral offset (ΔY) of the road vehicle (2) can be fed from the lane centre (6) for determining a change in steering angle (Δα).

7. Assistance system (1) according to one of claims 1 to 6, - wherein the signal line (9) is formed by the contact wires (18) of a two-pole overhead contact line system designed as an outgoing and return conductor for supplying energy to the road vehicle (2), wherein the contact wires (18) for supplying energy can be contacted by an on-vehicle current collector (17).