CN111025266B

CN111025266B - Prism and multi-line laser radar

Info

Publication number: CN111025266B
Application number: CN202010037115.3A
Authority: CN
Inventors: 胡小波; 刘颖
Original assignee: LeiShen Intelligent System Co Ltd
Current assignee: LeiShen Intelligent System Co Ltd
Priority date: 2020-01-14
Filing date: 2020-01-14
Publication date: 2021-07-06
Anticipated expiration: 2040-01-14
Also published as: WO2021143665A1; CN111025266A

Abstract

The invention discloses a prism and a multi-line laser radar. The prism comprises a reflection part, the reflection part comprises at least two reflectors which are sequentially arranged along a central shaft, the at least two reflectors comprise a first reflector and a second reflector, the first reflector comprises a plurality of first reflection surfaces which are arranged around the central shaft, the second reflector comprises a plurality of second reflection surfaces which are arranged around the central shaft, the number of the first reflection surfaces is larger than that of the second reflection surfaces, and the maximum value of the absolute values of included angles between the first reflection surfaces and the central shaft is smaller than the maximum value of the absolute values of included angles between the second reflection surfaces and the central shaft. The prism and the multi-line laser radar provided by the invention have the advantages that the number of scanning light beams is increased, the manufacturing cost and the manufacturing difficulty of the multi-line laser radar are reduced, and the volume and the debugging workload of the multi-line laser radar are reduced.

Description

Prism and multi-line laser radar

Technical Field

The embodiment of the invention relates to the technical field of laser radars, in particular to a prism and a multi-line laser radar.

Background

With the development of laser technology, laser scanning technology is more and more widely applied to the fields of measurement, traffic, driving assistance, mobile robots and the like. The laser radar is a radar system for detecting the position, speed and other characteristic quantities of a target by laser, and the working principle of the radar system is that a detection laser beam is firstly emitted to the target, then a signal reflected from the target is received and compared with an emitted signal, and after appropriate processing, the information of the distance, direction, height, speed, attitude, even shape and the like of the target can be obtained.

In some special application places, the performance parameter standards of all aspects of the laser radar are quite high, such as detection field angle, detection precision, detection density, volume, service life and the like. However, in the conventional multi-line laser radar, the number of scanning light beams is increased by increasing the number of laser light sources, so that the detection field angle is increased, and the detection density is increased.

Disclosure of Invention

The invention provides a prism and a multi-line laser radar, which are used for reducing the manufacturing cost and the manufacturing difficulty of the multi-line laser radar, reducing the volume of the multi-line laser radar and debugging workload while increasing the number of scanning light beams.

In a first aspect, an embodiment of the present invention provides a prism, including a reflection portion; the reflecting part comprises at least two reflectors which are sequentially arranged along a central axis, the at least two reflectors comprise a first reflector and a second reflector,

the first reflector comprises a plurality of first reflecting surfaces arranged around the central shaft, the second reflector comprises a plurality of second reflecting surfaces arranged around the central shaft, the number of the first reflecting surfaces is larger than that of the second reflecting surfaces, and the maximum value of the absolute values of included angles between the first reflecting surfaces and the central shaft is smaller than the maximum value of the absolute values of included angles between the second reflecting surfaces and the central shaft.

Optionally, the number of the first reflective surfaces is D1, and the number of the second reflective surfaces is D2;

d1 ═ N × D2, where N is a positive integer greater than or equal to 2; d2 is a positive integer greater than or equal to 3.

Optionally, there are D2 first reflection surfaces in the first reflection body, which are in one-to-one correspondence with the second reflection surfaces, and at least part of boundaries between the first reflection surfaces and the second reflection surfaces in one-to-one correspondence are overlapped.

Optionally, the included angle between each first reflecting surface and the central axis is different, and/or the included angle between each second reflecting surface and the central axis is different.

Optionally, the reflection part further comprises a third reflector; the first reflector, the second reflector and the third reflector are arranged in sequence along the central axis; the third reflector comprises a plurality of third reflecting surfaces arranged around the central axis; the number of the third reflecting surfaces is larger than that of the second reflecting surfaces, and the maximum value of the absolute values of included angles between each third reflecting surface and the central shaft is smaller than the maximum value of the absolute values of included angles between each second reflecting surface and the central shaft.

Optionally, the reflection part further comprises a third reflector; the third reflector, the first reflector and the second reflector are arranged in sequence along the central axis; the third reflector comprises a plurality of third reflecting surfaces arranged around the central axis; the number of the third reflecting surfaces is smaller than that of the first reflecting surfaces, and the maximum value of absolute values of included angles between each third reflecting surface and the central shaft is larger than the maximum value of absolute values of included angles between each first reflecting surface and the central shaft.

Optionally, the prism comprises at least two of the reflecting parts; the at least two reflecting portions include a first reflecting portion and a second reflecting portion that are sequentially arranged along the central axis.

In a second aspect, an embodiment of the present invention further provides a multiline lidar, including any one of the prisms described in the first aspect, further including: the rotating mechanism is connected with the prism and is used for driving the prism to rotate around a rotating shaft of the prism; the rotating shaft is coaxial with the central shaft;

at least one group of transmitting and receiving components, wherein the transmitting and receiving components comprise a transmitting unit and a receiving unit; the emitting unit is positioned on one side of the prism and used for emitting laser beams; the laser beam emitted by the emitting unit is reflected by the first reflecting part of the prism and then irradiates a target detection area; the receiving unit and the transmitting unit in the same group of transmitting and receiving assemblies are positioned on the same side of the prism and used for receiving the laser beams reflected by the second reflecting part of the prism after being reflected from the target detection area.

Optionally, the central axis of the prism is a hollow shaft; the rotating mechanism is arranged in the hollow shaft.

Optionally, the multiline laser radar includes a first transmitting and receiving module and a second transmitting and receiving module, where the first transmitting and receiving module and the second transmitting and receiving module are respectively disposed on different sides of the rotating shaft;

the scanning detection area of the first transmitting and receiving assembly is at least partially overlapped with the scanning detection area of the second transmitting and receiving assembly.

The prism provided by the embodiment of the invention has the advantages that the reflecting part at least comprises a first reflecting body and a second reflecting body which are sequentially arranged along the central axis, the first reflecting body comprises a plurality of first reflecting surfaces which are arranged around the central axis, the second reflecting body comprises a plurality of second reflecting surfaces which are arranged around the central axis, the number of the first reflecting surfaces is larger than that of the second reflecting surfaces, the maximum value of the absolute values of the included angles between the first reflecting surfaces and the central axis is smaller than that between the second reflecting surfaces and the central axis, the angle of view in the direction of the central axis can be increased while the laser beam passes through the prism in a partial area in the direction of the central axis and has higher scanning density, and the density scanning of the reflected beam on a detection field can be realized; moreover, the prism can reduce the manufacturing cost and the manufacturing difficulty of the multi-line laser radar, and reduce the volume and the debugging workload of the multi-line laser radar.

Drawings

Fig. 1 is a schematic structural diagram of a prism according to an embodiment of the present invention;

FIG. 2 is a schematic front view of the prism shown in FIG. 1;

FIG. 3 is an enlarged partial schematic view of FIG. 2;

FIG. 4 is a schematic structural diagram of another prism provided in an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of another prism provided in an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a multiline lidar according to an embodiment of the present invention;

FIG. 7 is a schematic view of a portion of the structure of FIG. 6;

FIG. 8 is a schematic diagram of a partial cross-sectional structure of another multiline lidar in accordance with an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of another multiline lidar according to an embodiment of the present invention;

FIG. 10 is a cross-sectional view taken at HH-HH in FIG. 9;

FIG. 11 is a cross-sectional view taken at GG-GG in FIG. 9;

fig. 12 is a schematic diagram illustrating a principle of a multiline lidar according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of a prism according to an embodiment of the present invention, and fig. 2 is a schematic front view of the prism shown in fig. 1, as shown in fig. 1 and fig. 2, the prism according to the embodiment of the present invention includes a reflection portion 10, the reflection portion 10 includes at least two reflection bodies sequentially disposed along a central axis 21, the at least two reflection bodies include a first reflection body 111 and a second reflection body 112, the first reflection body 111 includes a plurality of first reflection surfaces 31 disposed around the central axis 21, the second reflection body 112 includes a plurality of second reflection surfaces 32 disposed around the central axis 21, the number of the first reflection surfaces 31 is greater than the number of the second reflection surfaces 32, and a maximum value of absolute values of angles between the respective first reflection surfaces 31 and the central axis 21 is smaller than a maximum value of absolute values of angles between the respective second reflection surfaces 32 and the central axis 21. That is, the inclination of each first reflecting surface 31 of the first reflecting body 111 with respect to the central axis 21 is small, and the inclination of each second reflecting surface 32 of the second reflecting body 112 with respect to the central axis is large.

The prism provided by the embodiment of the invention can be used in a multi-line laser radar, light emitted by a laser light source in the multi-line laser radar can be reflected to a target detection area through the reflection part 10 of the prism, and a laser beam reflected back by the target detection area is reflected to a receiver in the multi-line laser radar through the reflection part 10, so that the reflected laser beam is properly processed to obtain information such as distance, direction, height, speed, attitude and the like of a target.

In the prism, the reflection part 10 at least comprises a first reflection body 111 and a second reflection body 112 which are sequentially arranged along the central axis 21, the first reflection body 111 comprises a plurality of first reflection surfaces 31 arranged around the central axis 21, and the second reflection body 112 comprises a plurality of second reflection surfaces 32 arranged around the central axis 21, so when the prism is used as a rotary reflection component of the multi-line laser radar, when laser beams emitted by the multi-line laser light source are projected on the reflection part 10, a part of the laser beams emitted by the laser device are projected on the first reflection surfaces 31, and a part of the laser beams emitted by the laser device are projected on the second reflection surfaces 32. Because the number of the first reflecting surfaces 31 is larger than that of the second reflecting surfaces 32, and the maximum value of the absolute values of the included angles between each first reflecting surface 31 and the central axis 21 is smaller than that between each second reflecting surface 32 and the central axis 21, that is, the inclination of each first reflecting surface 31 is smaller, after the laser beam is reflected by the first reflecting surface 31 of the first reflecting body 111 of the rotating prism, a dense light distribution can be formed in the corresponding area along the direction of the central axis 21, and after the laser beam is reflected by the second reflecting surface 32 of the second reflecting body 112, a sparse light distribution can be formed in the corresponding area along the direction of the central axis 21, so that a dense distribution can be formed on the whole field of view, and the use requirements can be met. Further, since the range of the angle between the second reflecting surface 32 and the central axis 21 is large, a large angle of view can be secured in the direction along the central axis 21, and since the number of the second reflecting surfaces 32 is small, a wide angle of view can be secured in the direction perpendicular to the central axis 21. That is, through above-mentioned prism, can increase the quantity of scanning pencil, this scheme need not to increase the quantity of laser source and receiver, reduces multi-thread lidar's the cost of manufacture and the preparation degree of difficulty, reduces multi-thread lidar's volume and debugging work load.

Illustratively, as shown in FIG. 1, the prisms are vertically disposed, i.e., their central axes 21 are disposed in a vertical direction. The first reflector 111 is an octahedral prism including 8 first reflecting surfaces 31, the second reflector 112 is a tetrahedral prism including 4 second reflecting surfaces 32, the 8 first reflecting surfaces 31 of the octahedral prism have different included angles with the central axis 21, the 4 second reflecting surfaces 32 of the tetrahedral prism have different included angles with the central axis 21, the first reflecting surface 31 in the octahedral prism has a smaller inclination angle with respect to the central axis 21, and the second reflecting surface 32 of the tetrahedral prism has a larger inclination angle with respect to the central axis 21. The laser light beams emitted by the laser light source of the multi-line laser radar are respectively projected onto the first reflecting surface 31 of the octahedral prism and the second reflecting surface 32 of the tetrahedral prism. After the prism is rotated for one circle, the laser beams emitted by the same laser are incident on the first reflector 111, can be reflected by 8 first reflecting surfaces 31 of the octahedral prism and then projected in different vertical directions, so as to be expanded into 8 laser beams. Similarly, the laser beams emitted by the same laser are incident on the second reflector 112, and can be reflected by the 4 second reflection surfaces 32 of the tetrahedral prism and projected in different vertical directions, so that the laser beams are expanded to form 4 lines of laser beams, and thus 12 lines of laser beams can be formed in the vertical direction. The specific number of lines of the lidar may be determined according to the number of lasers that are set. For example, if 32 lasers are provided in the multiline laser radar, and the laser beams of 21 lasers are incident on the octahedral prism and 11 lasers are incident on the tetrahedral prism, the number of laser lines that can be formed in the vertical direction is: and 21 × 8+11 × 4-212 lines, so that a higher number of laser radar lines can be realized by using fewer lasers, the complexity of the laser radar is favorably reduced, and the miniaturization and the low cost of the laser radar are realized. Meanwhile, through the reflection of the prism, the multi-line laser beams can be distributed sparsely and densely in the direction along the central axis 21, that is, the sparsely and densely distributed vertical field of view is realized, so that the region which needs to be strictly focused has higher resolution, and the laser radar can have a larger field angle in the vertical direction (that is, along the central axis 21). The field angle of the laser radar in the vertical direction and the resolution thereof need to be set according to the setting of the emitting angle of each laser and the setting of the inclination angles of the two reflectors. In the present embodiment, the octahedral prism can achieve 60-degree horizontal scanning (i.e. perpendicular to the central axis 21 direction) for each group of transceiver units, and the tetrahedral prism can achieve 120-degree horizontal scanning, so that the horizontal scanning angle range of the middle dense area is 60-70 degrees, and the total horizontal scanning angle is 130-150 degrees, or even larger, thereby ensuring that the laser radar has a larger scanning field of view.

Fig. 3 is a partial enlarged view of fig. 2, and as shown in fig. 3, a maximum value a1 of absolute values of an included angle between each first reflection surface 31 and the central axis 21 is smaller than a maximum value a2 of absolute values of an included angle between each second reflection surface 32 and the central axis 21 along the central axis 21. The laser beam is rotated by the prism to form a plurality of reflected beams, and the maximum value a1 in the absolute value of the included angle between the first reflecting surface 31 and the central axis 21 is set to be smaller along the direction of the central axis 21, so that the plurality of reflected beams formed by reflection by the first reflecting body 111 are concentrated in the corresponding area of the scanning detection area of the laser radar, the scanning density of the corresponding area of the scanning detection area is increased, and the resolution in the area is improved. For example, when the multi-line laser radar using the prism is applied to the field of automatic driving or other self-moving devices, the situation in the area right in front is usually more concerned, and the prism can ensure that the scanning density of the area right in front is denser, has extremely high resolution, is beneficial to quickly and accurately detecting the obstacle in the area, reduces the probability of missed detection of the obstacle, is beneficial to preventing a vehicle from colliding with the obstacle in front, and improves the safety of the automatic driving process. Illustratively, the angle between the first reflective surface 31 and the central axis 21 is between-0.2 ° and +0.2 °, and the angle between the second reflective surface 32 and the central axis 21 is between-2 ° and +2 °, so as to achieve sparse and dense scanning of the target detection area by the reflected light beam, wherein "+" and "-" represent that the directions of the reflective surfaces pointing to the central axis 21 are opposite directions, for example, "+" indicates that the direction of the reflective surface pointing to the central axis 21 is counterclockwise, and "-" indicates that the direction of the reflective surface pointing to the central axis 21 is clockwise.

The prism provided by the embodiment of the invention can ensure that the laser beam passes through the prism and has higher scanning density in a partial area along the central axis 21 direction, and simultaneously, the field angle in the central axis 21 direction is increased, and the density scanning of the reflected light beam on the detection field can be realized by arranging the reflecting part 10 at least comprising the first reflecting body 111 and the second reflecting body 112 which are sequentially arranged along the central axis 21, wherein the first reflecting body 111 comprises a plurality of first reflecting surfaces 31 arranged around the central axis 21, the second reflecting body 112 comprises a plurality of second reflecting surfaces 32 arranged around the central axis 21, the number of the first reflecting surfaces 31 is larger than that of the second reflecting surfaces 32, and the maximum value a1 in the absolute value of the included angle between each first reflecting surface 31 and the central axis 21 is smaller than the maximum value a2 in the absolute value of the included angle between each second reflecting surface 32 and the central axis 21; and the prism also reduces the manufacturing cost and the manufacturing difficulty of the multi-line laser radar, and reduces the volume and the debugging workload of the multi-line laser radar.

With continued reference to fig. 1, optionally, the number of the first reflective surfaces 31 is D1, the number of the second reflective surfaces 32 is D2, and D1 is N × D2, where N is a positive integer greater than or equal to 2; d2 is a positive integer greater than or equal to 3. In other embodiments, D1 may be larger than D2.

Illustratively, as shown in fig. 1, D1 is 8, D2 is 4, and N is 2, wherein the number D1 of the first reflecting surfaces 31 is multiplied by the number D2 of the second reflecting surfaces 32, so that the edges of the partial reflecting surfaces between the two reflecting bodies are overlapped, and the precision of the seam between the first emitter 311 and the second emitter 312 is easier to ensure. For example, the first reflector 111 is a hexahedral prism, the second reflector 112 is a trihedral prism, or the first reflector 111 is an octahedral prism, and the second reflector 112 is a tetrahedral prism or a trihedral prism. Of course, the first reflector 111 and the second reflector 112 may be combined in other ways, and are not limited to the above examples.

With continued reference to fig. 1, optionally, there are D2 first reflective surfaces 31 corresponding to the second reflective surfaces 32 in the first reflective body 111, and at least part of the boundaries between the first reflective surfaces 31 and the second reflective surfaces 32 corresponding to each other coincide.

For example, as shown in fig. 1, 4 first reflecting surfaces 31 in the first reflecting body 111 correspond to the second reflecting surfaces 32 one to one, and the first reflecting surfaces 31 and the second reflecting surfaces 32 corresponding to one have partially overlapped boundaries, so that the light energy of the laser beam incident on the seam between the first emitting body 311 and the second emitting body 312 is not greatly lost while the precision of the seam between the first reflecting body 111 and the second reflecting body 112 is further ensured. In one embodiment, the first reflector 111 and the second reflector 112 may be a single body, i.e. polished by a prism, with less light energy loss. In another embodiment, the first reflector 111 and the second reflector 112 may be seamlessly spliced by using a bonding process. Since each reflecting surface of the first reflecting body 111 coincides with the edge of part of the second reflecting surface 32 on the second reflecting body 112, the two parts can be easily aligned accurately, so as to ensure that the seam has high precision and does not bring large energy loss.

Optionally, the included angles between the first reflecting surfaces 31 and the central axis 21 are different, and/or the included angles between the second reflecting surfaces 32 and the central axis 21 are different. The distribution of the inclination angles of the first reflecting surfaces 31 and the distribution of the inclination angles of the second reflecting surfaces 32 may be set according to the distribution of density in the vertical direction, which is to be achieved as needed, and is not limited to any particular case. When the included angles of the first reflecting surfaces 31 and the second reflecting surfaces 32 are different, the laser radar can generate the maximum number of laser lines, so that the miniaturization and the low cost of the laser radar are facilitated.

Wherein, along the direction of the central axis 21, the included angles between any two first reflection surfaces 31 and the central axis 21 are different, when the laser beam emitted by the laser source is emitted to the first reflection body 111, because the included angles between different first reflection surfaces 31 and the central axis 21 are different, the reflected beams in different directions can be formed in the direction of the central axis 21, when the prism rotates, the reflected beams can scan the target object in the direction perpendicular to the central axis 21, exemplarily, as shown in fig. 1, the first reflection body 111 includes 8 first reflection surfaces 31, when the prism rotates for a circle, the laser beam emitted by the laser source can form 8 scanning beams in different directions, so that the angular resolution in the direction of the central axis 21 is smaller, the detection density of the central area of the target detection area is improved, and at the same time, the number of the laser source and the receiver does not need to be increased, the complexity and the cost of the multi-line laser radar are reduced. Similarly, along the central axis 21 direction, the included angles between any two second reflection surfaces 32 and the central axis 21 are different, and different reflected light beams are formed in the central axis 21 direction, for example, as shown in fig. 1, the second reflection body 112 includes 4 second reflection surfaces 32, and when the prism rotates for one circle, the laser beam emitted by the laser source can form 4 scanning beams in different directions, so that the detection density of the edge region of the target detection region is improved, and the complexity and cost of the multi-line laser radar are reduced.

It should be noted that the projection angle of the reflected light beam in the direction of the central axis 21 (i.e. the angle relative to the central axis) can be adjusted by adjusting the angle between each first reflecting surface 31 or second reflecting surface 32 and the central axis 21, so as to realize the density distribution of the reflected light beam in the field of view along the central axis 21. Illustratively, the included angle between the first reflecting surface 31 and the central axis 21 is in an arithmetic progression arrangement between-0.2 ° and +0.2 °, and the included angle between the second reflecting surface 32 and the central axis 21 is in an arithmetic progression arrangement between-2 ° and +2 °, so as to realize a partially dense and partially sparse distribution structure of the reflected light beam on the detection field of view, and to ensure that the multiline laser radar has a larger field angle in a direction perpendicular to the central axis 21, and at the same time, can measure farther and smaller obstacles in the field of view in front of the vehicle.

Fig. 4 is a schematic structural diagram of another prism according to an embodiment of the present invention, as shown in fig. 4, optionally, the reflection portion 10 further includes a third reflector 113; the first reflector 111, the second reflector 112 and the third reflector 113 are sequentially arranged along the central axis 21, the third reflector 113 comprises a plurality of third reflecting surfaces 33 arranged around the central axis 21, the number of the third reflecting surfaces 33 is larger than that of the second reflecting surfaces 32, and the maximum value a3 of absolute values of included angles between the third reflecting surfaces 33 and the central axis 21 is smaller than the maximum value a2 of absolute values of included angles between the second reflecting surfaces 32 and the central axis 21.

Wherein, the number of laser radar lines is further increased by increasing the third reflector 113, increasing the number of third reflecting surfaces 33 arranged around the central axis 21, and making the number of third reflecting surfaces 33 larger than the number of second reflecting surfaces 32. Meanwhile, by setting the maximum value a3 in the absolute values of the included angles between the third reflecting surfaces 33 and the central shaft 21 to be smaller than the maximum value a2 in the absolute values of the included angles between the second reflecting surfaces 32 and the central shaft 21, the reflected light beams can be distributed in three different densities on the detection view field, and the design flexibility of the multi-line laser radar is improved.

With continued reference to FIG. 4, the third reflector 113 and the first reflector 111 may alternatively be constructed identically.

The third reflector 113 with the same structure as the first reflector 111 is added, so that light rays can be distributed in a sparse middle and dense two sides along the central axis direction, and the use requirement under a specific scene is met. Such a distribution may be used, for example, when high attention needs to be paid to the regions on both sides.

Fig. 5 is a schematic structural diagram of another prism provided in an embodiment of the present invention, and in another embodiment, as shown in fig. 5, the prism also includes a third reflector 113. The third reflector 113 likewise includes a plurality of third reflective surfaces 33 disposed about the central axis 21. At this time, the third reflector 113, the first reflector 111, and the second reflector 112 are sequentially disposed along the direction of the central axis 21. The number of the third reflecting surfaces 33 of the third reflecting body 113 is smaller than the number of the first reflecting surfaces 31, and the maximum value a3 of the absolute values of the included angles between the third reflecting surfaces 33 and the central axis 21 is larger than the maximum value a1 of the absolute values of the included angles between the first reflecting surfaces 31 and the central axis 21. At this time, the third reflector 113 and the second reflector 112 can reflect the laser beam to form relatively sparse light distribution, and the first reflector 111 can reflect the laser beam to form relatively dense light distribution, so as to form dense middle distribution and sparse sides distribution in the direction of the central axis 21, thereby satisfying the use requirement of a specific scene. This distribution may be used, for example, when high attention is needed to the intermediate region. In an embodiment, the third reflector 113 and the second reflector 112 have the same structure and are symmetrically disposed on two sides of the first reflector 111, so that the center of gravity of the whole prism is stable.

It should be noted that the shapes of the prisms shown in the drawings of the present invention are only schematic and not limiting to the present invention, and the number of reflectors and the number of reflective surfaces in each reflector can be set according to actual requirements, for example, the reflective portion includes two reflectors, i.e., a first reflector 111 and a second reflector 112, the first reflector 111 includes 6 first reflective surfaces 31, and the second reflector 112 includes 3 second reflective surfaces 32. Wherein, the scanning angle range of the middle dense region of the target detection region can be between 60 ° and 70 ° by setting the number of the first reflecting surfaces 31 in the first reflecting body 111; by setting the number of the second reflecting bodies 112 in the second reflecting bodies 112, the total scanning angle of the target detection area is between 130 ° and 150 °.

With continued reference to fig. 1, optionally, there are at least two reflective portions 10 in the prism, and the two reflective portions 10 respectively include a first reflective portion 41 and a second reflective portion 42 sequentially disposed along the central axis 21. When the prism is applied to a laser radar, the first reflection part 41 and the second reflection part 42 function as reflection parts that emit a laser beam and an echo laser beam, respectively.

Illustratively, light emitted by a laser source in the multi-line laser radar is reflected to a target detection area through a first reflection part 41 of a prism, and a laser beam reflected back from the target detection area is reflected to a receiver inside the multi-line laser radar through a second reflection part 42, so that after the reflected laser beam is appropriately processed, information of distance, direction, height, speed, attitude and the like of a target is obtained. By arranging the second reflecting part 42 on the prism, the laser beam reflected by the target detection area can be reflected to the receiver, so that the requirement on the field angle of a receiving lens is effectively reduced, the area of a photosensitive surface of the receiver is reduced, and the cost of the multi-line laser radar system is reduced.

With continued reference to fig. 1 and 2, optionally, the second reflective portion 42 has the same structure as the first reflective portion 41, for example, as shown in fig. 1 and 2, the second reflective portion 42 includes a third reflective body 113 and a fourth reflective body 114, the third reflective body 113 includes a plurality of third reflective surfaces 33 disposed around the central axis 21, the fourth reflective body 114 includes a plurality of fourth reflective surfaces 34 disposed around the central axis 21, the third reflective body 113 has the same structure as the first reflective body 111, and the fourth reflective body 114 has the same structure as the second reflective body 112. The scanning beam formed by the reflection of the first reflector 111 is reflected to the third reflector 113 through the object in the target detection area and further reflected to the receiving lens, and the scanning beam formed by the reflection of the second reflector 112 is reflected to the fourth reflector 114 through the object in the target detection area and further reflected to the receiving lens, so that the one-to-one correspondence between the receiving and the transmitting of the beams is achieved.

According to the prism provided by the embodiment of the invention, the first reflecting surface 31 and the second reflecting surface 32 are provided with partially overlapped boundaries, so that the accuracy of the seam between the first reflector 111 and the second reflector 112 is ensured, and meanwhile, the light energy loss of a laser beam when the laser beam is incident on the seam between the first emitter 311 and the second emitter 312 is less. Through setting up the contained angle inequality between each first plane of reflection 31 and the center pin 21, and/or the contained angle inequality between each second plane of reflection 32 and the center pin 21, make laser beam can form many reflected beams that are different angles on the center pin 21 direction after the prism reflection, further increase multi-thread lidar is at the ascending scanning resolution ratio of center pin 21 side, and need not to increase the quantity of laser source and receiver, when improving the detection density, reduce multi-thread lidar's volume and debugging work load.

The first reflection part 41 and the second reflection part 42 are arranged, and the first reflection part 41 and the second reflection part 42 are provided with opposite light paths, so that the reflection and the receiving of the laser beams are completed, and a receiver with a large photosensitive surface is not required to be specially arranged to receive the laser beams reflected by the object in the target detection area, so that the effects of reducing the manufacturing cost and the manufacturing difficulty of the multi-line laser radar system are realized.

Based on the same inventive concept, an embodiment of the present invention further provides a multi-line laser radar, fig. 6 is a schematic structural diagram of the multi-line laser radar provided in the embodiment of the present invention, and as shown in fig. 6, the multi-line laser radar 50 includes a prism 51 described in any embodiment of the present invention, so that the multi-line laser radar 50 provided in the embodiment of the present invention has the technical effects of the technical solutions in any embodiment described above, and explanations of structures and terms that are the same as or corresponding to the embodiments described above are not repeated herein. As shown in fig. 6, the multi-line lidar further comprises a rotating mechanism 52 connected to the prism 51 for rotating the prism 51 around a rotating shaft 81 of the prism 51, wherein the rotating shaft 81 is coaxial with the central shaft 21. At least one group of emission-receiving components 53, the emission-receiving components 53 include an emission unit 531 and a receiving unit 532, the emission unit 531 is located at one side of the prism 51 and is used for emitting laser beams, the laser beams emitted by the emission unit 531 are reflected by the first reflection part 41 of the prism 51 and then irradiate the target detection area, and the receiving unit 532 is located at the same side of the prism 51 as the emission unit 531 in the same group of emission-receiving components 53 and is used for receiving the laser beams reflected by the second reflection part 42 of the prism 51 after being reflected from the target detection area.

Exemplarily, fig. 7 is a partial schematic structure diagram of fig. 6, and as shown in fig. 7, the laser beam emitted by the emitting unit 531 is reflected by the rotating first reflecting portion 41, wherein the upper angle beam is incident on the first reflecting body 111, and the lower angle beam is incident on the second reflecting body 112, so that the number of reflected beams is increased, and the scanning resolution is increased. The scanning beam is diffusely reflected by the target surface in the target detection region, reflected by the second reflecting portion 42, and received by the receiving unit 532. Since the first reflection part 41 and the second reflection part 42 have the same structure, the scanning beams with different angles are focused on the receiving unit 532 after being reflected by the second reflection part 42, so as to obtain information of distance, direction, height, speed, posture, even shape, and the like of the target.

With continued reference to fig. 7, optionally, the emitting unit 531 comprises an emitting plate 61 and a plurality of emitters 62, the plurality of emitters 62 being located on the emitting plate 61; the receiving unit 532 includes a receiving plate 63 and a plurality of receivers 64, and the plurality of receivers 64 are located on the receiving plate 63. Illustratively, as shown in fig. 7, 32 emitters 62 are integrated on an emission board 61 for emitting a plurality of laser beams (hereinafter, referred to as probe signals). In other embodiments, the number of the emitters 62 integrated on the emitting plate 61 can be set according to implementation requirements, and is not limited herein, and the emitters 62 can be fiber lasers, Laser Diodes (LDs), gas lasers, solid state lasers, or the like. The receiving board 63 is correspondingly integrated with 32 receivers 64, and the receivers 64 are disposed in one-to-one correspondence with the transmitters 62 and used for receiving a plurality of laser beams (hereinafter referred to as echo signals). It is understood that in other embodiments, the number of integrated receivers 64 on the receiving board 63 may be set according to implementation requirements, and is not limited herein, and the receivers 64 may be implemented by a plurality of Avalanche Photodiodes (APDs) arranged in an array, a single large-area APD, a focal plane array detector, a silicon photomultiplier (MPPC) detector arranged in a single point or array, or other types of array detectors known to those skilled in the art. By arranging that the transmitters 62 in each transmitting unit 531 are integrated on one transmitting board 61 and the receivers 64 in each receiving unit 532 are integrated on one receiving board 63, the transmitting angle and the receiving angle can be debugged at one time without independently debugging each transmitter 62 or each receiving board 63, thereby reducing the debugging difficulty and simplifying the debugging process. It should be noted that the number of the transmitters 62 and the receivers 64 can be arbitrarily set according to actual requirements.

With continuing reference to fig. 6 and 7, optionally, the multiline lidar provided by the embodiment of the present invention further includes a filter 54, a transmitting lens 55 and a receiving lens 56, where the transmitting lens 55 is located on a propagation path of the outgoing light of the transmitter 62, and the transmitting lens 55 includes one or more spherical lenses for collimating the light emitted by the transmitter 62; the receiving lens 56 is located on the propagation path of the laser beam reflected by the second reflection part 42 of the prism 51, and the receiving lens 56 includes one or more spherical lenses for focusing the laser beam reflected by the second reflection part 42 of the prism 51 on the receiver 64, wherein the spherical lenses of the transmitting lens 55 and the receiving lens 56 can be replaced by aspheric lenses, thereby reducing the number of lenses and further reducing the volume of the multiline laser radar. A filter 54 is located between the emission lens 55 and the emitter 62, and/or a filter 54 is located between the receiving lens 56 and the receiver 64 for filtering out ambient light. It can be understood that, because there may be interference caused by ambient light such as sunlight and various lights in the environment to the signal received by the receiving unit 532, by setting the filter 54, the ambient light can be filtered out, and the measurement accuracy of the multiline laser radar system is improved.

Alternatively, the plurality of emitters 62 are arranged in a direction parallel to the rotational axis 81 of the prism 51.

Illustratively, as shown in fig. 7, the emitters 62 arranged on each emitting plate 61 are distributed in a plane in the vertical direction, and the included angle between the direction in which each emitter 62 emits laser light and the horizontal direction is different, the laser beam emitted by each emitter 62 sequentially strikes each reflecting surface of the first reflecting portion 41, and the included angle between each reflecting surface and the rotating shaft 81 of the prism 51 is set to be different in the vertical direction, so that the laser beam is expanded into a plurality of laser beams in the vertical direction; as the prism 51 rotates, the laser beam scans in the horizontal direction. The receivers 64 on the receiving board 63 are arranged at positions and angles corresponding to the transmitters 62 one by one, and detection signals at different angles can be received by only the corresponding receivers 64. Therefore, the number of the laser beams in the vertical direction can be expanded and the field scanning in the horizontal direction can be realized by rotating the prism 51, the line number of the laser beams is expanded on the premise of not increasing laser light sources, and the cost is reduced.

Fig. 8 is a schematic partial cross-sectional view of another multiline lidar according to an embodiment of the present invention, in which the central shaft 21 of the prism 51 is a hollow shaft, and the rotating mechanism 52 is disposed in the hollow shaft.

The rotating mechanism 52 may be a motor, as shown in fig. 8, the rotating mechanism 52 is disposed in the hollow shaft of the prism 51 to drive the prism 51 to rotate, so that the space can be fully utilized and the volume can be reduced.

Fig. 9 is a schematic structural diagram of another multiline lidar according to an embodiment of the present invention, fig. 10 is a sectional view taken from HH to HH in fig. 9, and fig. 11 is a sectional view taken from GG to GG in fig. 9, as shown in fig. 9 to 11, optionally, the multiline lidar includes a first transceiver module 71 and a second transceiver module 72, the first transceiver module 71 and the second transceiver module 72 are respectively disposed on different sides of the rotating shaft 14, and a scanning detection area of the first transceiver module 71 at least partially overlaps a scanning detection area of the second transceiver module 72.

Illustratively, as shown in fig. 9, the first transmission and reception assembly 71 includes a plurality of transmitters and a plurality of receivers, the second transmission and reception assembly 72 also includes a plurality of transmitters and a plurality of receivers, the plurality of laser beams emitted from the first transmission and reception assembly 71 and the second transmission and reception assembly 72 are at different angles in the vertical direction, the plurality of laser beams are reflected by the rotating prism 51, and when the laser beams are incident on the prism 51, the laser beams are expanded into the plurality of laser beams in the vertical direction. In the present embodiment, the scanning areas of the first transceiver component 71 and the second transceiver component 72 may have an overlapping area of 90 °, so that the overlapping area has a higher angular resolution. The first transmitting-receiving assembly 71 and the second transmitting-receiving assembly 72 are symmetrically arranged relative to the prism 51, so that the mass distribution of the whole system structure is uniform, and the rotation is more stable. After the laser beams emitted by the first transmitting and receiving assembly 71 and the second transmitting and receiving assembly 72 are subjected to diffuse reflection on the target surface in the detection target area, the laser beams are reflected by the prism 51 again and received by a plurality of different receivers in the first transmitting and receiving assembly 71 and the second transmitting and receiving assembly 72 respectively, the laser beams at different angles can be received by only corresponding receivers, and three-dimensional coordinate information of the target can be obtained according to angle information output by the photoelectric code disc in the multi-line laser radar and distance information measured by the multi-line laser radar. In other embodiments, the first transceiver component 71 and the second transceiver component 72 may be disposed on different sides of the rotation axis, such as adjacent sides of the prism, so that the horizontal scan field of view can exceed 180 degrees, even approaching 270 degrees.

With continued reference to fig. 9-11, optionally, the first transmit receive assembly 71 includes a first transmit unit 711, a first transmit bracket plate 712, a first transmit conversion plate 713, a first transmit mirror 714, and a first transmit lens 715. The first emission unit 711 includes an emission plate and a plurality of emitters integrated on the emission plate, and the emission plate and the first emission conversion plate 713 are disposed on the first emission bracket plate 712. The first emission conversion plate 713 is provided thereon with an emission driving circuit for driving the emitters to emit laser beams. The first transmitting mirror 714 includes two mirrors for changing the optical direction of the transmitted laser beam, so that the structure of the whole first transmitting and receiving assembly 71 is more compact, wherein the mirrors are not necessary components, and the mirrors can be replaced by prisms or vibrating mirrors, and those skilled in the art can arrange the mirrors according to actual requirements.

With continued reference to fig. 9-11, optionally, the first transmission and reception assembly 71 further includes a first reception unit 716, a first reception support plate 717, a first reception conversion plate 718, a first reception mirror 719, and a first reception lens 710. The first receiving unit 716 includes a receiving plate and a plurality of receivers integrated on the receiving plate, and the receiving plate and the first receiving conversion plate 718 are disposed on the first receiving bracket plate 717. The operational amplifier circuit is disposed on the first receiving conversion board 718 for amplifying the echo signal. The first receiving mirror 719 includes two mirrors for changing the optical direction of the received laser beam, so that the structure of the whole first transmission and reception assembly 71 is more compact, wherein the mirrors are not necessary components, and the mirrors can be replaced by prisms, and those skilled in the art can arrange the mirrors according to actual needs.

The second transceiver 72 and the first transceiver 71 have the same structure, so the second transceiver 72 can refer to the description of the first transceiver 71 and will not be described herein.

In other embodiments, the multiline lidar further comprises an optoelectronic code disc 73, wherein the optoelectronic code disc 73 is arranged on the prism 51 and is used for detecting and outputting angle information of the prism 51 and/or speed information of the rotating mechanism 52. For example, the photoelectric code disc 73 can output the angle information of the prism 51 and the speed information of the feedback rotating mechanism 52 in real time to be applied to control the rotating speed of the rotating mechanism 52.

Fig. 11 is a schematic diagram of a multiline lidar according to an embodiment of the present invention, and as shown in fig. 11, the multiline lidar according to an embodiment of the present invention exemplarily includes a first transceiver module 71, a second transceiver module 72, a prism (not shown), a motor, an optical encoder, and a main control board 57 (positions of the main control board are also shown in fig. 9 and 10), and the main control board 57 is electrically connected to the first transceiver module 71, the second transceiver module 72, the motor, and the optical encoder, respectively. The main control board 57 includes a power supply, a Field Programmable Gate Array (FPGA), a network interface chip, and an analog-to-digital converter (ADC). The first transceiver module 71 includes a transmitting lens, an LD, a transmitting driving circuit, a receiving lens, an APD, and an operational amplifier, and the second transceiver module 72 has the same structure as the first transceiver module 71. Specifically, the power supply is used for supplying power to all modules needing power in the multi-line laser radar, such as a transmitting drive circuit, an FPGA (field programmable gate array), a motor and the like. The FPGA controls the transmitting and driving circuit to drive the LDs on the first transmitting and receiving assembly 71 and the second transmitting and receiving assembly 72 to transmit laser beams according to a preset sequence, the laser beams are emitted out through the transmitting lens to serve as detection signals to reach a target detection area, echo signals reflected by a target object in the target detection area reach the APD through the receiving lens to realize photoelectric conversion, then, the first-stage amplification and the second-stage amplification are realized through an operational amplifier, the analog-to-digital conversion is realized through an ADC (analog-to-digital converter) and enters an FPGA (field programmable gate array), the FPGA processes, analyzes and calculates the processed echo signal to obtain result data (such as one or more parameters of the distance, the direction, the height, the speed, the posture and the shape of a target object), the result data is output in a point cloud data mode through a network interface chip, meanwhile, the FPGA can also control the frequency, the power and the like of laser beams emitted by the LD according to the information fed back by the photoelectric code disc. Optionally, the multi-line lidar may further include a Micro Control Unit (MCU), and the MCU and the FPGA control each module of the multi-line lidar together

The multiline laser radar provided by the embodiment of the invention comprises a prism 51 and at least one group of transmitting and receiving components 53, wherein laser beams transmitted by the transmitting and receiving components 53 are reflected by a first reflecting part 41 of the prism 51 and then irradiate a target detection area, and are reflected by an object in the target detection area and then return to the transmitting and receiving components 53 after being reflected by a second reflecting part 42 of the prism 51, so that the detection function is completed. By providing the central shaft 21 of the prism 51 as a hollow shaft and providing the rotating mechanism 52 in the hollow shaft, the space can be fully utilized and the volume of the multiline lidar can be reduced. Through setting up two transmission receiving assembly, further improved laser radar's line number, when the increase scanning range, can also improve and survey density. The scanning areas of the two transmitting and receiving assemblies comprise the overlapping area, so that the overlapping area has higher angular resolution.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A prism, comprising a reflective portion; the reflecting part comprises at least two reflectors which are sequentially arranged along a central axis, the at least two reflectors comprise a first reflector and a second reflector,

the first reflector comprises a plurality of first reflecting surfaces arranged around the central axis, the second reflector comprises a plurality of second reflecting surfaces arranged around the central axis, the number of the first reflecting surfaces is greater than that of the second reflecting surfaces, and the maximum value of the absolute values of included angles between each first reflecting surface and the central axis is smaller than the maximum value of the absolute values of included angles between each second reflecting surface and the central axis;

the number of the first reflecting surfaces is D1, and the number of the second reflecting surfaces is D2;

d1= N × D2, wherein N is a positive integer greater than or equal to 2; d2 is a positive integer greater than or equal to 3.

2. The prism of claim 1, wherein there are D2 of the first reflective surfaces in the first reflector in a one-to-one correspondence with the second reflective surfaces, at least some of the boundaries between the one-to-one correspondence of the first reflective surfaces and the second reflective surfaces being coincident.

3. The prism of claim 1, wherein the included angle between each of the first reflective surfaces and the central axis is unequal and/or the included angle between each of the second reflective surfaces and the central axis is unequal.

4. The prism of claim 1, wherein the reflective portion further comprises a third reflector; the first reflector, the second reflector and the third reflector are arranged in sequence along the central axis; the third reflector comprises a plurality of third reflecting surfaces arranged around the central axis; the number of the third reflecting surfaces is larger than that of the second reflecting surfaces, and the maximum value of the absolute values of included angles between each third reflecting surface and the central shaft is smaller than the maximum value of the absolute values of included angles between each second reflecting surface and the central shaft.

5. The prism of claim 1, wherein the reflective portion further comprises a third reflector; the third reflector, the first reflector and the second reflector are arranged in sequence along the central axis; the third reflector comprises a plurality of third reflecting surfaces arranged around the central axis; the number of the third reflecting surfaces is smaller than that of the first reflecting surfaces, and the maximum value of absolute values of included angles between each third reflecting surface and the central shaft is larger than the maximum value of absolute values of included angles between each first reflecting surface and the central shaft.

6. A prism as claimed in any one of claims 1 to 5, characterized in that the prism comprises at least two of the reflecting portions; the at least two reflecting portions include a first reflecting portion and a second reflecting portion that are sequentially arranged along the central axis.

7. A multiline lidar comprising the prism of claim 6 and further comprising:

the rotating mechanism is connected with the prism and is used for driving the prism to rotate around a rotating shaft of the prism; the rotating shaft is coaxial with the central shaft;

8. Multiline lidar according to claim 7 wherein the central axis of said prism is a hollow shaft; the rotating mechanism is arranged in the hollow shaft.

9. The multiline lidar of claim 7, including a first transceiver component and a second transceiver component, the first transceiver component and the second transceiver component being disposed on different sides of the rotational axis, respectively;