DE102020110822A1 - Method for recognizing a radial movement of a lidar measuring point and an object - Google Patents

Abstract

The invention relates to a method for recognizing a radial movement of at least one lidar measuring point (i1 to i4) in a vehicle or robot environment. According to the invention, lidar measurement points (i1 to i4) are recorded in data recorded by means of a lidar (2) in the vehicle or robot environment. Furthermore, radar positions (j1 to j3) are recorded in data recorded by means of a radar (3) in the vehicle or robot environment and associated radial speeds are determined, with at least one radar position (j1 to j3) being assigned to each of the lidar measurement points (i1 to i4) and for at least one lidar measuring point (i1 to i4) based on the at least one assigned radar position (j1 to j3) and whose radial speed it is determined whether the lidar measuring point (i1 to i4) moves radially.
The invention further relates to a method for detecting a radial movement of at least one object in a vehicle or robot environment and a method for operating a vehicle (1) and / or robot.

Description

The invention relates to a method for recognizing a radial movement of at least one lidar measuring point in a vehicle or robot environment.

The invention also relates to a method for detecting a radial movement of an object in a vehicle or robot environment.

The invention also relates to a method for operating a vehicle and / or robot.

• - Senden von mindestens einem rampenförmig frequenzmodulierten Radar-Sendesignal durch mindestens eine Sendevorrichtung und Empfangen von mindestens einem von mindestens einem Ziel reflektierten Radar-Empfangssignal,
• - Übertragen des Radar-Empfangssignals an eine Auswerteeinheit und Umwandeln des mindestens einen empfangenen Radar-Empfangssignals in digitale Messwerte,
• - Durchführen einer zweidimensionalen Fourier-Transformation aus einem Betragsspektrum der digitalen Messwerte,
• - Detektion von mindestens einem Zielreflex eines Zieles anhand von Scheitelwerten in einem Betragsspektrum,
• - Bestimmen von einer Entfernung eines Zieles von der Sendevorrichtung, einer Radialgeschwindigkeit und einer Transversalgeschwindigkeit eines Zieles relativ zu der Sendevorrichtung,
• - Bestimmen von mindestens einem Winkel des mindestens einen Zieles relativ zu einer Ausrichtung der Sendevorrichtung.

From the DE 10 2017 204 496 A1 a method for determining an acceleration of a target by means of radar waves is known with the following steps:

• - Sending at least one ramp-shaped, frequency-modulated radar transmission signal by at least one transmission device and receiving at least one radar reception signal reflected from at least one target,
• - Transmitting the radar received signal to an evaluation unit and converting the at least one received radar received signal into digital measured values,
• - Carrying out a two-dimensional Fourier transformation from an absolute spectrum of the digital measured values,
• - Detection of at least one target reflex of a target based on peak values in a magnitude spectrum,
• - determining a distance of a target from the transmitting device, a radial speed and a transverse speed of a target relative to the transmitting device,
• - Determination of at least one angle of the at least one target relative to an orientation of the transmitting device.

Based on the determination of the distance, the relative radial speed and the angle, all other target reflexes and interferences are suppressed except for the respective target reflex of a target. For these target reflexes of physical targets, after an inverse Fourier transformation has been carried out, radial accelerations are approximately calculated from the transformed measured values. Furthermore, a radar device with a transmission device for transmitting a radar transmission signal, with a reception device for receiving a reflected radar reception signal and with an evaluation unit for converting the radar reception signals into digital measured values and for processing the digital measured values is described.

The invention is based on the object of specifying an improved method for detecting a radial movement of at least one lidar measuring point in a vehicle or robot environment and an improved method for detecting a radial movement of an object in a vehicle or robot environment. The invention is also based on the object of specifying a method for operating a vehicle and / or robot.

The object is achieved according to the invention by a method for recognizing a radial movement of at least one lidar measuring point, which has the features specified in claim 1, by a method for recognizing a radial movement of an object, which has the features specified in claim 7, and by a method for operating a vehicle and / or robot which has the features specified in claim 8.

Advantageous refinements of the invention are the subject matter of the subclaims.

In the method for detecting a radial movement of at least one lidar measurement point in a vehicle or robot environment, according to the invention, lidar measurement points are recorded in data recorded by means of a lidar in the vehicle or robot environment and radar positions are recorded and associated with data recorded by means of radar in the vehicle or robot environment Radial speeds determined. At least one radar position is assigned to each of the lidar measuring points and for at least one lidar measuring point it is determined on the basis of the at least one assigned radar position and its radial speed whether the lidar measuring point is moving radially.

Lidars enable, for example, a three-dimensional model of the environment to be generated in automated, in particular highly automated or autonomous vehicles and / or in robots. Using data recorded by means of a radar, the method makes it possible to distinguish between lidar measurement points that are moved in the radial direction and that are not moving, in particular on the basis of data from a single frame and without complex data processing. That is, the method makes it possible in a particularly advantageous manner that lidar measurement points enriched with radar information can be used on the basis of individual frames to distinguish between radially moving and non-moving lidar measurement points. As a result, the environment model and a driving behavior of an automated driving vehicle and / or robot can be improved.

In particular, the method continues to use the radar information before a central merging step, so that a computing load, energy consumption and requirements for an executing hardware can be reduced.

The method can thus be used, for example, in applications in which it is recognized whether vehicles located at the roadside are stationary, for example parked, or are in motion. Furthermore, the method can be used, for example, in applications in which it is recognized whether objects represented by lidar measurement points are moving in the direction of a route of a vehicle.

In one possible embodiment of the method, weights which indicate a measure of the reliability of the assignment are determined and taken into account when assigning the radar positions to the lidar measurement points. That means: Radar positions, also referred to as radar reflections, are weighted and associated with lidar measurement points and thus estimated radial velocities are transferred from radar positions to lidar measurement points. The weighting can improve the accuracy and reliability of the method.

In a further possible embodiment of the method, a distance of the respective lidar measuring point from the radar is taken into account when determining the weights. This can also improve the accuracy and reliability of the method.

In a further possible embodiment of the method, a lateral and / or elevation angle of the respective lidar measuring point to the radar is taken into account when determining the weights. This can also improve the accuracy and reliability of the method.

In a further possible embodiment of the method, after the assignment of the radar positions to the lidar measurement points, an indicator for the presence of a radial movement and an indicator for the absence of a radial movement are determined for the lidar measurement points, the indicators being determined as a function of the weights the assignments and the associated radial velocities is carried out. This makes it possible to distinguish between radially moving and non-moving lidar measurement points in a particularly simple and reliable manner.

In a further possible embodiment of the method, the indicators of a lidar measuring point are used to classify whether the lidar measuring point is moving in the radial direction, not moving, or whether a classification is not possible.

In the method according to the invention for detecting a radial movement of at least one object in a vehicle or robot environment, a radial movement of at least one lidar measuring point in the vehicle or robot environment is recognized according to the method described above and for an object represented by the at least one lidar measuring point based on the At least one radar position assigned to a lidar measuring point and its radial speed are determined as to whether the object is moving radially.

The method makes it possible, using data recorded by means of a radar and the lidar measurement points, to distinguish between objects that are moving in the radial direction and those that are not moving, in particular on the basis of data from a single frame and without complex data processing. That is to say, the method makes it possible in a particularly advantageous manner that a distinction can be made between radially moving and non-moving objects on the basis of individual frames by means of lidar measurement points enriched with radar information. As a result, the environment model and a driving behavior of an automated driving vehicle and / or robot can be improved.

In the method for operating a vehicle and / or robot, the vehicle and / or robot is controlled in an automated, in particular highly automated or autonomously driving mode, depending on a radial movement of at least one lidar measuring point detected by means of a method described above and / or depending carried out a radial movement of at least one object detected by means of a method described above.

Due to the use of data recorded by means of a radar and the lidar measurement points to distinguish moving objects from immobile objects in the radial direction, in particular on the basis of data from a single frame and without complex data processing, it is particularly advantageous to use lidar measurement points enriched with radar information on the basis of individual frames can be distinguished between radially moving and non-moving objects. As a result, an environment model, a movement behavior and a driving behavior of an automated driving vehicle and / or a robot can be improved.

In one possible embodiment of the method, depending on a speed of the at least one lidar measuring point and / or depending on a speed of the at least one object, a safety maneuver is carried out, for example to avoid a collision with an object and / or a hazard to the same and to the vehicle and / or robot to avoid.

In a further possible embodiment of the method, a movement of the vehicle and / or robot is stopped or at least slowed down in the safety maneuver and / or an emergency trajectory is automatically followed to reach a safe location. Such safety maneuvers are particularly suitable for avoiding, for example, a collision with an object and / or a hazard to the same and to the vehicle and / or robot.

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

• 1 schematisch eine Draufsicht eines Fahrzeugs und eines Ausschnitts einer Fahrzeugumgebung.

Show:

• 1 schematically a top view of a vehicle and a section of a vehicle environment.

In the only one 1 Fig. 3 is a plan view of a vehicle 1 and a section of a vehicle environment as well as a two-dimensional coordinate system with an X-axis x and a Y-axis y shown. The vehicle 1 includes at least one lidar 2 and a radar 3 for environment detection.

The lidar 2 uses a laser to scan different directions in space on a regular grid. A distance to a first object or obstacle is determined by a transit time of backscattered laser light. A combination of known angle and measured distance enables a Cartesian, three-dimensional coordinate of a position of a backscattering lidar measuring point to be determined i1 until i4 . Under lidar measurement points i1 until i4 are also understood here as so-called pixels.

Based on by means of the lidar 2 however, the acquired data is not a direct measurement of a radial speed of a lidar measuring point i1 until i4 possible, so that a lidar measurement alone does not make it possible to decide whether a lidar measurement point is required without complex data processing and object recognition over several frames i1 to i4 originates from an object moving or not moving in the radial direction.

To solve this problem, the lidar measuring points are provided i1 until i4 with radar positions j1 until j3 , also known as radar reflections, and information about the radial velocity of the associated radar positions j1 until j3 to be used to provide a statement about the radial movement of the respective lidar measuring point i1 until i4 hold true. To the represented radar positions j1 until j3 closed curves are shown, each showing confidence ranges K1 until K3 include, that is, areas in which the radar positions j1 until j3 causing reflections are very likely.

The association is weighted, i.e. a lidar measuring point i1 until i4 can have multiple radar positions j1 until j3 be assigned. A radar position j1 until j3 can in turn with any number of lidar measuring points i1 until i4 be associated.

A weight of an assignment to a radar position j1 until j3 to a lidar measurement point i1 until i4 is determined, for example, as described below.

bestimmt. Hierbei gibt die Funktion N(x;y,R) eine Dichte einer Normalverteilung mit einem Mittelwert y und einer Kovarianzmatrix R an einer Stelle x an. Ein Vektor z_i beinhaltet für den Lidarmesspunkt i1 bis i4 erwartete Entfernungs- und Winkelmessungen, das heißt $$z_i={\left[r_i,u_i\right]}^T,$$

wobei r_i eine Entfernung des jeweiligen Lidarmesspunkts i1 bis i4 zum Radar 3 und u_i den Kosinus eines Einfallswinkels, beispielsweise eines Seiten- und/oder Höhenwinkels, in einem Radar-Antennenkoordinatensystem angeben. Des Weiteren bezeichnet y_j Messgrößen der Radarpositionen j1 bis j3 und R_j ist eine Fehlerkovarianzmatrix der Radarmessgrößen.First, in a first step, weights w̃ _{i, j are used} accordingly as an intermediate result $${\tilde{w}}_{i,j}:=N\left(z_i;y_j,{\mathrm{R.}}_j\right)$$

certainly. The function N (x; y, R) gives a density of a normal distribution with a mean value y and a covariance matrix R at one point x at. A vector z _{i contains} for the lidar measuring point i1 until i4 expected distance and angle measurements, that is $$z_i={\left[r_i,u_i\right]}^T,$$

where r _{i is} a distance of the respective lidar measuring point i1 until i4 to the radar 3 and u _i indicate the cosine of an angle of incidence, for example a lateral and / or elevation angle, in a radar antenna coordinate system. Furthermore, y _j denotes measured variables of the radar positions j1 until j3 and R _j is an error covariance matrix of the radar metrics.

zu normalisieren. Hier ist κ > 0 konfigurierbar. Aufgrund dieser Normalisierung liegen die Gewichte im Intervall [0,1].In a second step, the intermediate results determined in the first step are used to calculate weights w _{i, j} according to $$w_{i,j}:=\frac{{\tilde{w}}_{i,j}}{\kappa +{\displaystyle {\sum }_{j=1}^J{\tilde{w}}_{i,j}}}$$

to normalize. Here κ> 0 can be configured. Because of this normalization, the weights are in the interval [0.1].

In a third step, small values of w _{i, j are set} to 0 if w _{i, j} <t _discard . Here, t _{discard specifies} a limit below which associations are neglected.

In addition to the weighting, the lidar measurement points are classified i1 until i4 with regard to a radial movement, that is to say a movement and / or speed classification.

und $$I_{noradmov,i}={\displaystyle \sum _{j=1}^J{w}_{i,j}|\left(\left|v_{r,j}\right|\le t_{mov}\right)}$$

ein Indikator I_{rad mov,i} für ein Vorhandensein einer radialen Bewegung und ein Indikator I_{no rad mov,i} für ein Nicht-Vorhandensein einer radialen Bewegung ermittelt.In a first step, each lidar measuring point i1 until i4 with an index i according to $${\mathrm{I.}}_{radmOv,i}={\displaystyle \sum _{j=1}^J{w}_{i,j}|\left(\left|v_{r,j}\right|>t_{mOv}\right)}$$

and $${\mathrm{I.}}_{nOradmOv,i}={\displaystyle \sum _{j=1}^J{w}_{i,j}|\left(\left|v_{r,j}\right|\le t_{mOv}\right)}$$

an indicator I _{rad mov, i} for the presence of a radial movement and an indicator I _{no rad mov, i} for a non-presence of a radial movement are determined.

Here, v _{r, j} gives one for a respective associated radar position j1 until j3 measured radial velocity and t _mov configures the radial velocity above which a radar position j1 until j3 is viewed as moving.

In a second step, the indicators are used for the classification.

Here it is decided that no classification is possible if $${\mathrm{I.}}_{radmOv,i}+{\mathrm{I.}}_{nOradmOv,i}<t_{min}.$$

dann wird der Lidarmesspunkt i1 bis i4 als sich in radialer Richtung bewegend klassifiziert.if $${\mathrm{I.}}_{radmOv,i}>{\alpha }_1{\mathrm{I.}}_{nOradmOv,i},$$

then the lidar measurement point becomes i1 until i4 classified as moving in a radial direction.

dann wird der Lidarmesspunkt i1 bis i4 als sich nicht in radialer Richtung bewegend klassifiziert.if $${\mathrm{I.}}_{radmOv,i}\le \frac{1}{{\alpha }_2}{\mathrm{I.}}_{nOradmOv,i},$$

then the lidar measurement point becomes i1 until i4 classified as not moving in a radial direction.

Here, α ₁ and α ₂ (each ≥ 1) are configuration variables for the weighting of the indicators.

For the scenario shown with four lidar measurement points i1 until i4 and three radar positions j1 until j3 According to the processes described above, the following weights result for the association: Table 1 j1 i2 i3 i1 0.5 0.1 0 i2 0.2 0.2 0 i3 0 0.3 0 i4 0 0 0

According to Table 1, the lidar measuring point i1 with a weight of 0.5 the radar position j1 and with a weight of 0.1 the radar position j2 associated. The radar position j3 will not match the lidar measuring point i1 associated, as it is very far from this. With the lidar measuring point i2 the radar positions are equally weighted at 0.2 each j1 , j2 associated. With the lidar measuring point i3 becomes the radar position with a weight of 0.3 j2 associated. With the lidar measuring point i4 will not be a radar position j1 until j3 associated as all radar positions j1 until j3 far from the lidar measurement point i4 away.

The following parameters are now assumed: Table 2 Radar speed radar position j1 v _{r, 1} 0 m / s Radar speed radar position j2 v _{r, 2} 5 m / s Barrier for motion detection t _mov 1 m / s Relative weighting of I _{no rad mov, i} for motion detection α ₁ 2 Relative weighting of I _{rad mov, i} for the detection of a fixed lidar measuring point i1 to i4 α ₂ 2 Minimum sum of Ino _{rad mov, i} and I _{rad mov, i required for a classification} t _min 0.25

This results in the following indicator variables and classifications: Table 3 I _{rad mov, i} I _{no rad mov, i} classification Lidar measuring point i1 0.1 0.5 Not moving radially Lidar measuring point i2 0.2 0.2 No classification possible Lidar measuring point i3 0.3 0 Moving radially Lirlarmess ninks i4 0 0 No classification possible

• - Lidarmesspunkt i1 wird als sich nicht radial bewegend klassifiziert, da er sich nah an der Radarposition j1 befindet, die keine Radialgeschwindigkeit aufweist.
• - Für Lidarmesspunkt i2 wird keine Entscheidung getroffen, da er sich ungefähr gleich weit von den Radarpositionen j1, j2 entfernt befindet, von denen die Radarposition j2 eine Radialgeschwindigkeit aufweist und die Radarposition j1 nicht.
• - Lidarmesspunkt i3 wir als sich radial bewegend klassifiziert, da er sich in der Nähe von der Radarposition j2 befindet, die eine Radialgeschwindigkeit aufweist.
• - Für Lidarmesspunkt i4 wird keine Entscheidung getroffen, da sich keine Radarposition j1 bis j3 in dessen Nähe befindet, die einen Rückschluss auf dessen Radialgeschwindigkeit ermöglicht.

The classification results are plausible for the following reasons:

• - Lidar measuring point i1 is classified as not moving radially because it is close to the radar position j1 is located, which has no radial velocity.
• - For lidar measuring point i2 no decision is made because it is roughly equidistant from the radar positions j1 , j2 away from which the radar position j2 has a radial velocity and the radar position j1 not.
• - Lidar measuring point i3 we classified as moving radially because it is close to the radar position j2 is located, which has a radial velocity.
• - For lidar measuring point i4 no decision is made as there is no radar position j1 until j3 is located in the vicinity, which allows a conclusion about its radial speed.

List of reference symbols

1

vehicle

2

Lidar

3

radar

i1 to i4

Lidar measurement point

K1 to K3

Confidence Range

j1 to j3

Radar position

x

X axis

y

Y axis

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 102017204496 A1 [0004]

Claims (10)

Method for recognizing a radial movement of at least one lidar measuring point (i1 to i4) in a vehicle or robot environment, characterized in that - in data recorded by means of a lidar (2) in the vehicle or robot environment, lidar measuring points (i1 to i4) are recorded, - Radar positions (j1 to j3) are recorded in data recorded by means of a radar (3) in the vehicle or robot environment and associated radial velocities are determined, - At least one radar position (j1 to j3) is assigned to each of the lidar measurement points (i1 to i4) and - for at least one lidar measuring point (i1 to i4) based on the at least one assigned radar position (j1 to j3) and its radial speed it is determined whether the lidar measuring point (i1 to i4) moves radially. Procedure according to Claim 1 , characterized in that weights which indicate a measure of the reliability of the assignment are determined and taken into account when assigning the radar positions (j1 to j3) to the lidar measurement points (i1 to i4). Procedure according to Claim 2 , characterized in that a distance of the respective lidar measuring point (i1 to i4) to the radar (3) is taken into account when determining the weights. Procedure according to Claim 2 or 3 , characterized in that a lateral and / or elevation angle of the respective lidar measuring point (i1 to i4) to the radar (3) is or is taken into account when determining the weights. Method according to one of the Claims 2 until 4th , characterized in that after the assignment of the radar positions (j1 to j3) to the lidar measurement points (i1 to i4) for the lidar measurement points (i1 to i4), an indicator for the presence of a radial movement and an indicator for the absence of a radial movement Movement is determined, the indicators being determined as a function of the weights of the assignments and the associated radial speeds. Method according to one of the preceding claims, characterized in that on the basis of the indicators of a lidar measuring point (i1 to i4) it is classified whether the lidar measuring point (i1 to i4) moves in the radial direction, does not move or a classification is not possible. A method for recognizing a radial movement of at least one object in a vehicle or robot environment, wherein a radial movement of at least one lidar measuring point (i1 to i4) in the vehicle or robot environment is recognized according to a method according to one of the preceding claims and for a by the at least An object represented by a lidar measuring point (i1 to i4) is determined on the basis of the radar position (j1 to j3) assigned to the at least one lidar measuring point (i1 to i4) and the radial speed of which determines whether the object is moving radially. Method for operating a vehicle (1) and / or robot, wherein a control of the vehicle (1) and / or robot in an automated operation as a function of a method according to one of the Claims 1 until 6th detected radial movement of at least one lidar measuring point (i1 to i4) and / or as a function of a by means of a method Claim 7 detected radial movement of at least one object is carried out. Procedure according to Claim 8 , a safety maneuver being carried out as a function of a speed of the at least one lidar measuring point (i1 to i4) and / or as a function of a speed of the at least one object. Procedure according to Claim 9 , wherein in the safety maneuver a movement of the vehicle (1) and / or robot is stopped or at least slowed down and / or an emergency trajectory is automatically followed to reach a safe location.

Images