DE102018132851A1 - Measuring arrangement - Google Patents

Abstract

The core idea of the present invention relates to a measuring system (10). The problem prevailing in conventional measuring systems of this type, namely the change in a scanning speed (S) in a measuring area (24) via the freedom of movement of a scanner (12), is caused by a local influence on the scanning speed (S) in the scanner area (34) of an optical element (28) solved.

Description

The present invention relates to a measuring arrangement according to the preamble of patent claim 1 and a vehicle according to the preamble of patent claim 10.

In the automotive field, for example in motor vehicles, the importance of measurement technology is constantly increasing. An example of this are LIDAR systems (English: "light detection and ranging") for optical distance and speed measurement which are well known to the person skilled in the art. Systems of this type are of particular interest, for example, in partially autonomous or autonomous vehicles.

In a LIDAR system, a light beam is deflected onto a measurement object via a scanner, for example a mirror that can be moved in one or more axes. The measurement object is scanned line by line, for example. Light that is reflected by the measurement object is then detected with a receiver. The distance of the measurement object is then determined, for example, from the transit time of the light or its phase shift. The speed can be determined, for example, from the change in the distance over time.

The result is that the temporal and spatial resolution of such a measuring system is directly dependent on the scanning speed. If the scanning speed is higher, a larger measuring range can be scanned in a shorter time. However, from a certain scanning speed, this brings the receiver to its technical performance limits, for example for signal transmission and evaluation. The measuring system must therefore be designed for a still permissible scanning speed.

Another disadvantage is that the scanning speed depends on the movement characteristics of the scanner. In particular when the direction of the scanner changes, for example, low scanning speeds result in the edge area of the measuring range, which even briefly become zero at the moment of the change of direction. On the other hand, if the scanner is, for example, in the middle of its travel path, it has a particularly high scanning speed, which, for example, leads to high scanning speeds in the middle of the measuring range.

If the scanner is moving at a constant speed, the technical performance limit of the receiver cannot be used in the peripheral areas, since otherwise the maximum permissible scanning speed would be exceeded in the middle of the measuring range.

This can be counteracted by an adapted motion control of the scanner, but this significantly increases the effort for the control and the actuators, especially since such scanners often move very quickly. It is therefore desirable to operate the scanner in a static operating state if possible.

From the EP 3 184 884 A1 For example, a method for controlling a headlight by adjusting the intensity of a light beam from a laser diode is known.

From the DE 10 2014 224 572 A1 For example, an illumination device emerges with which light from a light source, which is deflected via a scanner, can be modulated into a desired light distribution via a free-form reflector.

From the DE 10 2012 205 438 A1 a similar lighting device is known which can produce a desired light distribution in a projection using a scanner and a lens with variable refractive power.

It is the object of the present invention to find a technical solution with which the scanning speed can be optimally adapted to a given measuring range. In addition, the technical solution should be able to be used as flexibly as possible and implemented with little effort.

The object is solved by the subject matter of independent claims 1 and 10. Further preferred embodiments of the invention result from the other features mentioned in the subclaims.

• - eine Lichtquelle;
• - einen Scanner; und
• - einen Empfänger, die in einem optischen Messpfad derart angeordnet sind, dass Licht der Lichtquelle über den optischen Messpfad auf den Scanner emittierbar und über den Scanner auf einen Messbereich lenkbar ist und dass von dem Messbereich reflektiertes Licht von dem Empfänger erfassbar ist;

weiterhin umfassend:

• - ein optisches Element, das in dem optischen Messpfad zwischen dem Scanner und dem Messbereich angeordnet ist.

A first aspect of the present invention relates to a measuring arrangement comprising:

• - a light source;
• - a scanner; and
• a receiver which is arranged in an optical measurement path such that light from the light source can be emitted onto the scanner via the optical measurement path and directed to a measurement area via the scanner and that light reflected by the measurement area can be detected by the receiver;

still comprehensive:

• an optical element which is arranged in the optical measurement path between the scanner and the measurement area.

According to the invention, it is provided that the optical element is designed, a scanning speed of the light in at least one To modulate the area of the measuring area relative to a corresponding scanner area on the optical element.

The scanner can be, for example, a scanning mirror or micromirror. This can be mounted, for example, swinging around two axes, or it can also comprise two separate mirrors, each of which is mounted swinging about an axis. A resonant scanner can also be provided. The light source can include, for example, a laser light source that is particularly well suited for implementing measuring systems.

The light is deflected by the scanner and, for example, directed line by line over a defined scanner area on the optical element. The light on the optical element is deflected and radiated in the direction of the measuring range. The optical element is matched to the movement characteristics of the scanner. The optical element and the scanner are preferably arranged relative to one another such that the entire scanner area, in other words the area that can be illuminated by the scanner, lies on the optical element. The feature of the corresponding scanner area is to be understood in such a way that when one speaks, for example, of an edge area in the measurement area, reference is made to an edge area in the scanner area.

With the measuring arrangement according to the invention, it is advantageously possible, for example, to locally increase the scanning speed in the area of an outer edge of the measuring area compared to the scanning speed in the area of an outer edge of the scanner area on the optical element and thus to increase the temporal resolution of the measurement. It is also possible, for example, to reduce the scanning speed in a central area of the measuring area compared to the scanning speed in a central area of the scanner area on the optical element, so that a permissible scanning speed is not locally exceeded there.

The scanner can thus basically be moved at a high speed over its range of motion, which in principle has a high scanning speed on the optical element. The optical element compensates for the aforementioned scanning speed in the measuring range.

This is advantageously even possible solely by designing the physical properties of the optical element, which significantly reduces the effort and increases operational reliability.

In a preferred embodiment of the measuring arrangement of the invention it is provided that the optical element comprises a reflecting element.

A reflective element is particularly useful when the light source is capable of emitting different wavelengths, or the reflective element can be used particularly well for different light sources.

In a preferred embodiment of the measuring arrangement of the invention, it is provided that the reflecting element comprises a redistribution mirror.

With the redistribution mirror, the modulation of the scanning speed is possible in a particularly simple manner, since it can be easily produced, for example, as a free-form surface.

In a further preferred embodiment of the measuring arrangement of the invention, it is provided that the redistribution mirror has a curvature that always changes from an inner scanner area towards an outer scanner area.

The terms inside and outside refer here to a center of the scanner area on the optical element, here the reflecting element or the redistribution mirror. With such a continuously variable curvature, it is possible in a particularly simple manner to distribute scanning speeds, for example from the outer scanner area, over a larger angular area in the measuring area, so that the scanning speed at the edge of the measuring area is increased and at the same time reduced towards the central area of the measuring area. The curvature can for example be designed progressively from the inner scanner area to the outer scanner area and also change its direction. It is also possible to provide a segmented redistribution mirror.

In a further preferred embodiment of the measuring arrangement of the invention, it is provided that outer scanner areas of the redistribution mirror have a greater curvature than inner scanner areas.

In other words, a significantly greater influence on the scanning speed can be achieved towards the edge area of the measuring range, where the lowest scanning speeds occur conventionally.

In this way, the described increase in the scanning speed can be achieved over the entire outer measuring range.

In an alternative preferred embodiment of the measuring arrangement of the invention, it is provided that the optical element comprises a light-refractive element.

With a light-refractive element, the measuring arrangement can be particularly compact since the optical measuring path can be shortened. This can be achieved, for example, by the light passing through the refractive element.

In a further preferred embodiment of the measuring arrangement of the invention, it is provided that the light-refractive element has a refraction characteristic that always changes from an inner scanner area towards an outer scanner area.

In this case, the terms inside and outside refer to a center of the scanner area on the refractive element. With such a constantly changing refraction characteristic, it is possible in a particularly simple manner to distribute scanning speeds, for example from the outer scanner area, over a larger angular area in the measuring area and thus to increase the scanning speed at the edge of the measuring area and at the same time to reduce it towards the middle area of the measuring area. The refraction characteristic can, for example, be designed progressively from the inner scanner region to the outer scanner region and can also change its direction of refraction.

In a further preferred embodiment of the measuring arrangement of the invention, it is provided that outer scanner areas of the light-refractive element can produce a stronger light refraction than inner scanner areas.

In other words, a significantly greater influence on the scanning speed can be achieved towards the edge area of the measuring range, where the lowest scanning speeds occur conventionally. In this way, the described increase in the scanning speed can be achieved over the entire outer measuring range.

In a further preferred embodiment of the measuring arrangement of the invention, it is provided that the measuring arrangement is designed as a LIDAR system.

The advantages of the invention are particularly evident in such, but also in other beam-based, optical measuring systems. The performance of such systems can be significantly increased with little effort.

A second aspect of the present invention relates to a vehicle comprising at least one measuring arrangement according to the invention as described above.

The vehicle is preferably a motor vehicle.

It is particularly preferably a partially autonomous or autonomous motor vehicle, since such measuring arrangements, for example as a LIDAR system, are of particular importance.

In summary, in other words, it can be said that the core idea of the present invention relates to a measuring system. The problem prevailing in conventional measuring systems of this type, namely the change in the scanning speed in the measuring area via the freedom of movement of the scanner, is solved by locally influencing the scanning speed in the scanner area of an optical element.

The optical element on the one hand distributes the light from edge areas of its scanner area over a larger angular area to the measuring area and on the other hand focuses the light from a central area of its scanner area into a smaller angular area in which the light falls on the measuring area.

Unless otherwise stated in the individual case, the various embodiments of the invention mentioned in this application can advantageously be combined with one another.

• 1 eine Prinzipdarstellung einer erfindungsgemäßen Messanordnung;
• 2 eine Prinzipdarstellung eines alternativen optischen Elements; und
• 3 ein erfindungsgemäßes Kraftfahrzeug.

The invention is explained below in exemplary embodiments with reference to the accompanying drawing. It shows:

• 1 a schematic diagram of a measuring arrangement according to the invention;
• 2nd a schematic diagram of an alternative optical element; and
• 3rd a motor vehicle according to the invention.

1 shows a schematic diagram of a measuring arrangement according to the invention 10 . The elements of the measurement setup 10 are in the lower part of the 1 shown comprising a scanner 12th from a light source 14 with light 16 is supplied. In the present example, the light source includes 14 a laser light source 18th .

The scanner 12th in the present example comprises a scanning mirror which is mounted so as to be oscillatable about two axes. So the light can 16 with the scanner 12th in two dimensions, for example on one level. For simplification the representation is the way of light 16 with arrows as an optical measurement path 20 shown.

The measurement arrangement 10 also includes a recipient 22 . The recipient 22 is to simplify the following explanation of the functional principle of the measuring arrangement 10 schematically as part of the light source 14 shown, but can of course also locally regardless of the light source 14 to be ordered. In such cases, the person skilled in the art will independently provide components known to him, such as partially transparent mirrors, around the optical measurement path 20 in front of the light source 14 and the recipient 22 to pick up.

The recipient 22 , the light source 14 and the scanner 12th are in the optical measurement path 20 arranged so that the light 16 the light source 14 first on the scanner 12th arrives and via this into a measuring range 24th the measuring arrangement 10 reached. The size of the measurement area 24th is due to the freedom of movement of the scanner 12th as well as the distance of the measuring range 24th from the scanner 24th influenced. In the measuring range 24th For example, there may be an object, not shown here, whose distance, for example, is to be measured. The light 16 is reflected by the object and passes through the optical measurement path 20 back to the recipient 22 . There it will be from the recipient 22 detected.

This is with the measurement setup 10 in the present case a LIDAR system 26 realized.

In the optical path 20 is between the scanner 12th and the measuring range 24th an optical element 28 arranged. The optical element 28 is in the present example by a reflective element 30th formed that a redistribution mirror 32 includes.

The light 16 passes through the optical measurement path on its way 20 from the light source 14 to the measuring range 24th as well as on the way back through the optical measurement path 20 to the recipient 22 over a scanner area 34 of the optical element 28 .

The scanner area 34 is that area on the optical element 28 in which the scanner 12th due to its freedom of movement and its relative arrangement to the optical element 28 the light 16 can distribute. The measuring range 24th is consequently also due to the optical element 26 certainly.

The scanner area 34 includes inner scanner areas 36 and outer scanner areas 38 which are marked as examples. Similarly, the measuring range includes 24th inner measuring ranges 40 and outer measuring ranges 42 .

The optical element 28 is designed to be a scanning speed S _M of light 16 in the outer measuring ranges 42 versus a scan speed S _S of light 16 in with the outer measuring ranges 42 corresponding outer scanner areas 38 to modulate.

How this is done exemplarily is in the upper part of 1 schematically explained in more detail.

There is an example of the redistribution mirror 28 with the scanner area 34 shown in sections. An inner scanner area is also indicated 36 and an outer scanner area 38 . It can be seen that the redistribution mirror 32 a curvature 44 has, starting from the inner scanner area 36 towards the outer scanner area 38 always changed. The curvature 44 is in the outer scanner area 38 more pronounced here than in the inner scanner area 36 and alternates the direction of curvature in between in the present example.

Now hits from the scanner 12th in the outer scanner area 38 distributed light 16 on the redistribution mirror 28 , sweeps the light 16 a certain area there 46 when the scanner 12th moves on. This applies accordingly when the light 16 from the scanner 12th in the inner scanner area 36 is distributed for an area 48 .

Because the curvature 44 in the area 46 in the present case, however, is exemplary larger than in the area 48 , the light 16 , with the same movement of the scanner 12th , out of the area 46 over a larger area 50 in the measuring range 24th steered when it out of the field 48 over an area 52 in the measuring range 24th is directed. As a result, this increases the scanning speed S _M in the area 50 versus scan speed S _M in the area 52 . Due to the movement characteristics of the scanner 12th is the scanning speed S _S in the area 48 maximum and will be in the range 46 greatly reduced. Due to the described effect of the curvature 44 , this will be compensated.

A distribution is exemplary 54 the size of the areas shown by the light 16 with constant further movement of the scanner 12th from the inner measuring range 40 towards the outer measuring range 42 sweeps over. The size increases from the inside out.

The concrete geometric design of the reflective element 28 the person skilled in the art uses the technical teaching disclosed herein independently, depending on the desired influencing of the scanning speed S _M in the measuring range 24th .

2nd shows an alternative embodiment of the optical element 28 out 1 .

So it is also possible to replace the reflective element 28 a refractive element 56 to provide in an analogous manner, for example a lens 58 . The Lens 58 can have a refractive characteristic caused by the lens 58 radiated light 16 analogous to that in 1 principle described on the areas 50 and 52 distributed. The expert becomes the measuring arrangement 10 out 1 adjust accordingly so that the light 16 through the lens 58 through to the measuring range 24th can reach.

3rd shows a vehicle according to the invention 60 , in the present case a motor vehicle 62 , with a measuring arrangement according to the invention 10 Is provided.

The measurement arrangement 10 is as a LIDAR system 26 in the motor vehicle 62 integrated.

Reference list

10th

Measuring arrangement

12th

scanner

14

Light source

16

light

18th

Laser light source

20

optical measurement path

22

receiver

24th

Measuring range

26

LiDAR system

28

optical element

30th

reflective element

32

Redistribution mirror

34

Scanner area

36

inner scanner area

38

outer scanner area

40

inner measuring range

42

outer measuring range

44

curvature

46

Area

48

Area

50

Area

52

Area

54

distribution

56

refractive element

58

lens

60

vehicle

62

Motor vehicle

S _M

Scanning speed

S _S

Scanning speed

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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

• EP 3184884 A1 [0008]
• DE 102014224572 A1 [0009]
• DE 102012205438 A1 [0010]

Claims (10)

Measuring arrangement (10), comprising: - a light source (14); - a scanner (12); and - a receiver (22) which are arranged in an optical measurement path (20) such that the light (16) from the light source (14) can be emitted onto the scanner (12) via the optical measurement path (20) and via the scanner ( 12) can be directed to a measuring area (24) and that light (16) reflected by the measuring area (24) can be detected by the receiver (22); further comprising: an optical element (28), which is arranged in the optical measuring path (20) between the scanner (12) and the measuring area (24), characterized in that the optical element (28) is designed, a scanning speed ( S _M ) of the light (16) in at least one area (40, 42, 50, 52) of the measuring area (24) compared to a corresponding scanner area (34) on the optical element (28). Measuring arrangement (10) after Claim 1 , characterized in that the optical element (28) comprises a reflective element (30). Measuring arrangement (10) after Claim 1 , characterized in that the optical element (28) comprises a light refractive element (56). Measuring arrangement (10) after Claim 2 , characterized in that the reflective element (30) comprises a redistribution mirror (32). Measuring arrangement (10) after Claim 4 , characterized in that the redistribution mirror (32) has a curvature (44) which always changes from an inner scanner area (36) towards an outer scanner area (38). Measuring arrangement (10) after Claim 5 , characterized in that outer scanner areas (38) of the redistribution mirror (32) have a greater curvature (44) than inner scanner areas (36). Measuring arrangement (10) after Claim 3 , characterized in that the light-refractive element (56) has a refractive characteristic which always changes from an inner scanner area (36) towards an outer scanner area (38). Measuring arrangement (10) after Claim 7 , characterized in that outer scanner areas (38) of the light-refractive element (56) are able to produce a stronger light refraction than inner scanner areas (36). Measuring arrangement (10) according to one of the preceding claims, characterized in that the measuring arrangement (10) is designed as a LIDAR system (26). Vehicle (60), comprising at least one measuring arrangement (10) according to one of the Claims 1 to 9 .

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