DE102020004689A1 - Method for determining an inclination of a road surface for a vehicle - Google Patents

Abstract

The invention relates to a method for determining an inclination (a ') of a road surface (F1) for a vehicle (1). According to the invention it is provided that - a position of the sun and a height (h) of a traffic sign (2) in front of the vehicle (1) are detected on the vehicle side, - an expected shadow length (x) of the traffic sign is determined based on a horizontally running road surface (F1) and - The inclination (a ') of the road surface (F1) is determined on the basis of the expected shadow length (x) and an actually recorded shadow length (x') of the traffic sign (2).

Description

The invention relates to a method for determining an inclination of a road surface for a vehicle.

From the DE 198 21 617 C1 a method, a use of the method and a device for measuring the angle of inclination in laterally inclined curves in a motor vehicle are known. The lateral acceleration, which is perpendicular to the vehicle speed and parallel to the vehicle plane, the rate of rotation, which is perpendicular to the vehicle speed and perpendicular to the vehicle plane, and the vehicle speed are measured at the same time. By linking the lateral acceleration, the rate of rotation and the vehicle speed, the angle of inclination is calculated in real time.

The invention is based on the object of specifying a method for determining an inclination of a road surface for a vehicle.

The object is achieved according to the invention by a method which has the features specified in claim 1.

Advantageous embodiments of the invention are the subject of the subclaims.

A method for determining an inclination of a road surface for a vehicle provides, according to the invention, that the position of the sun and the height of a traffic sign in front of the vehicle are recorded on the vehicle side. Based on a horizontally running road surface, an expected shadow length of the traffic sign is determined and the inclination of the road surface is determined based on the expected shadow length and an actually recorded shadow length of the traffic sign.

By using the method, the angle of inclination of the road surface in front of the vehicle can be determined in a comparatively simple manner, on the basis of which a so-called inclination disturbance variable can be determined, which is taken into account in lateral control of the vehicle. As a result, comparatively fast and abrupt control pulses can be reduced in the transverse control, so that the safety and comfort for a vehicle user and occupants of the vehicle can be increased significantly. The lateral control becomes more even when the inclination is available as information, whereby a lateral inclination map of all routes can be created by storing and disseminating this information. This lateral inclination map is created by means of a plurality of vehicles that determine the inclinations, the determination taking place, in particular on sunny days, on the basis of the length of the shadow.

Embodiments of the invention are explained in more detail below with reference to drawings.

• 1 schematisch eine perspektivische Ansicht eines auf einem Fahrbahnabschnitt fahrenden Fahrzeuges sowie ein Verkehrsschild und
• 2 schematisch eine Ermittlung einer lateralen Neigung einer Fahrbahnoberfläche.

Show:

• 1 schematically a perspective view of a vehicle traveling on a roadway section and a traffic sign and
• 2 schematically a determination of a lateral inclination of a road surface.

Corresponding parts are provided with the same reference symbols in all figures.

1 Figure 11 shows a perspective view of one on a roadway section F. moving vehicle 1 and a shadow S. throwing road sign 2 , which is the vehicle 1 is a truck with a tractor and a trailer.

A lateral control, especially in the automated driving mode of the vehicle 1 , is a relatively complex task that simultaneously increases the safety and comfort of a vehicle user and occupant of the vehicle 1 influenced. External disturbances can cause a considerable loss of quality on the cross-regulation. One of these disturbance variables is an inclination a 'of a road surface F1 represent.

In particular about the lateral inclination a 'of the road surface F1 of the vehicle 1 road section ahead F. to detect, so that the inclination a 'can be taken into account with respect to the lateral control, a method described below is provided.

The vehicle 1 has an environmental sensor system, which a number of in and / or on the vehicle 1 arranged detection units, wherein at least one camera 3 Is part of the environmental sensors.

The camera 3 is in a front area of the vehicle 1 arranged and oriented such that the vehicle 1 section of road ahead F. is captured.

To determine the slope a 'of the road surface F1 it is required that the road sign 2 casts a shadow on the road surface F1 is shown and an object, in particular the traffic sign 2 , can be assigned to. It is assumed that that the object, i.e. the traffic sign 2 , is vertical to the earth's surface, with a vertical axis of the traffic sign 2 runs through the center of the earth. It is also assumed that the inclination a 'of the road surface F1 is constant.

The traffic sign is created on the basis of signals from the environmental sensors 2 detected, with a geometry of the traffic sign 2 , in particular its height h, is also determined on the basis of the detected signals.

Furthermore, a current time, a date and a geographical position of the traffic sign are included 2 known, being the shadow S. of the traffic sign 2 on the road surface F1 in the trajectory direction of the vehicle 1 falls as in 1 is shown.

To determine the lateral inclination a 'of the road surface F1 becomes an expected sunlight vector V and one between the road surface F1 and the expected sunlight vector V formed angle α is calculated based on the date, the current time and the geographical position.

Furthermore, the height of the traffic sign 2 based on the signals captured by the camera 3 , further detection units of the environment sensor system and / or determined on the basis of map data available on the vehicle side, with a current distance between the vehicle 1 and the traffic sign 2 is taken into account.

Furthermore, a shadow length x 'becomes on a trajectory of the vehicle 1 is recognized and a shadow length x is taken under consideration of the calculated sunlight vector V and the determined height h of the traffic sign 2 forecast as in 2 is shown.

mit a: vertikaler Winkel des Sonnenlichtvektors V $$\beta =180°-\alpha \text{'-}\gamma$$

mit β: tatsächliche Neigung der Fahrbahnoberfläche F1 $$\frac{x\text{'}}{sin\gamma }=\frac{x}{sin\alpha \text{'}}$$

$$\alpha \text{'=arcsin}\left(\frac{xsin\gamma }{x\text{'}}\right)\text{.}$$

A difference between the shadow length x 'and the predicted shadow length x is then determined and the lateral inclination a' of the road surface is determined using the following equations F1 calculated: $$\alpha +\gamma =180°$$

with a: vertical angle of the sunlight vector V $$\beta =180°-\alpha \text{'-}\gamma$$

with β: actual slope of the road surface F1 $$\frac{x\text{'}}{sin\gamma }=\frac{x}{sin\alpha \text{'}}$$

$$\alpha \text{'= arcsin}\left(\frac{xsin\gamma }{x\text{'}}\right)\text{.}$$

The method makes it possible to use several vehicles 1 away, information relating to the lateral slope a 'of the road surface F1 to generate in different places at different times.

The vehicles are used for this 1 as registration units and share, ie disseminate, their information. In particular, the shadows cast can only be detected on certain objects, ie on objects that are completely within the detection area E. a registration unit. This information relating to the lateral inclination a 'can be disseminated by means of vehicle-to-vehicle and / or vehicle-to-infrastructure communication.

This enables an inclination map to be created on sunny days, whereby the inclination map can be validated over the course of the year and different sun positions.

Especially for the automated driving of the vehicle 1 the lateral regulation of the same within road markings can thus be improved, since the lateral inclination a 'is known as a disturbance variable of the lateral regulation in certain inclined zones.

List of reference symbols

1

vehicle

2

Traffic sign

3

camera

E.

Detection area

F.

Lane section

F1

Road surface

S.

shadow

V

Sunlight vector

α '

Tilt

H

height

x

expected shadow length

x '

recorded shadow length

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 19821617 C1 [0002]

Claims (3)

Method for determining an inclination (a ') of a road surface (F1) for a vehicle (1), characterized in that - a position of the sun and a height (h) of a traffic sign (2) in front of the vehicle (1) are detected on the vehicle side, - an expected shadow length (x) of the traffic sign is determined based on a horizontally running road surface (F1) and - based on the expected shadow length (x) and an actually recorded shadow length (x ') of the traffic sign (2), the inclination (a') of the road surface (F1) is determined. Procedure according to Claim 1 , characterized in that the position of the sun is determined based on a current date, a current time and a geographical position of the traffic sign (2). Procedure according to Claim 1 or 2 , characterized in that the height (h) of the traffic sign (2) is determined based on map data and / or on the basis of detected signals from an environmental sensor system of the vehicle (1).

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