Ranging unit and multi-line laser radar

Abstract

The application discloses a ranging unit and a multi-line laser radar. The ranging unit comprises a transmitting module and a receiving module. The transmitting module comprises a transmitting support, a transmitting circuit board, a laser transmitter group, a transmitting optical assembly and a light outlet barrel which are arranged on the transmitting support, and the transmitting optical assembly forms a transmitting channel. The receiving module comprises a receiving support, a receiving cavity which is arranged in the receiving support and through which reflected laser from an object to be measured enters from a front port. The receiving cavity is provided with a receiving optical assembly and a photoelectric detector, and the receiving optical assembly forms a receiving channel. The transmitting and receiving optical assemblies are arranged in parallel channels, so that the emitting direction of the detection light beam and the incident direction of the echo light beam are approximately parallel, the structure of each optical device is relatively simple, and the alignment and adjustment process of the optical path is reduced or avoided. In addition, the transmitting optical assembly and the receiving optical assembly are both designed to be simplified, so that the beam shaping and transmitting / receiving functions are realized by as few lenses as possible.

Description

Technical Field

[0001] This invention relates to the field of lidar technology, specifically to ranging units and multi-line lidar. Background Technology

[0002] LiDAR, as an environmental perception sensor, accurately measures the distance, orientation, and reflection intensity of target objects by emitting laser beams and detecting their return signals, generating high-resolution point cloud data. Based on different scanning methods, LiDAR is mainly divided into three categories: mechanical rotating LiDAR, semi-solid-state LiDAR, and solid-state LiDAR. Among them, mechanical rotating LiDAR has become the mainstream solution for high-performance applications due to its ability to achieve 360° horizontal panoramic scanning and its stable and reliable point cloud.

[0003] Existing mechanical rotating lidar optical path structures are generally divided into two types: one is where the transmitting and receiving modules are fixed, and the rotating mirror is mounted on the motor rotor. The rotating mirror is driven by the motor to achieve beam scanning. In this scheme, the vibration of the rotating mirror at high speed will affect the accuracy, and the optical path alignment between the transmitting and receiving modules and the rotating mirror increases the difficulty of assembly and adjustment; the other is where the transmitting and receiving modules are both mounted on the motor rotor and rotate with the motor rotor. In this scheme, the rotating parts are bulky due to the integration of too many components. At the same time, the integrated rotation of the transmitting and receiving modules also introduces wireless power transmission and wireless communication, increasing the complexity of the system. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, a ranging unit and a multi-line lidar are provided, which simplify the lidar structure, avoid complex optical assembly and adjustment processes, and effectively improve manufacturing efficiency.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: The first aspect is the ranging unit, which includes a transmitting module and a receiving module; The transmitting module includes a transmitting bracket, on which a transmitting circuit board, a laser emitter group, a transmitting optical component and a light-emitting tube are arranged sequentially along the laser emission direction, and the transmitting optical component forms the transmitting channel; The receiving module includes a receiving bracket, within which a receiving cavity gradually expands from front to back. The receiving cavity has a front port and a rear port. The laser reflected by the object under test enters through the front port. Along the laser incident direction, receiving optical components and a photodetector are arranged sequentially on the receiving cavity. The receiving optical components form a receiving channel. A receiving circuit board electrically connected to the photodetector is located at the rear port of the receiving cavity. The transmitting bracket and the receiving bracket are fixedly connected; the receiving channel and the transmitting channel are set in parallel and tilted at a set angle to the horizontal direction.

[0006] According to the above technical solution, a light-blocking plate is provided between the transmitting bracket and the receiving bracket, and the light-blocking plate is located between the light-emitting tube and the front port of the receiving cavity.

[0007] According to the above technical solution, the laser emitter group is provided in two groups, each group of laser emitters contains a number of laser emitters, and each laser emitter corresponds to multiple point light sources. The two sets of laser emitters are arranged in an alternating vertical arrangement; or, each laser emitter in one set is arranged alternately with the laser emitters in the other set.

[0008] According to the above technical solution, the transmitting optical components include a collimating lens group, a transmitting filter, and a deflecting and expanding mirror arranged sequentially along the laser emission direction; there are multiple collimating lens groups, and the number of collimating lens groups is the same as the number of laser emitter groups. A collimating lens group is provided on the optical path of the detection beam emitted by each laser emitter group; each collimating lens group includes a fast-axis collimating lens and a slow-axis collimating lens arranged sequentially along the laser emission direction.

[0009] According to the above technical solution, multiple photodetectors are disposed on the receiving circuit board, and each photodetector contains several detection units; There is a one-to-one correspondence between photodetectors and laser emitter groups; or one photodetector corresponds to multiple laser emitter groups; or multiple photodetectors correspond to one laser emitter group.

[0010] According to the above technical solution, the transmitting bracket is fixed on one side of the receiving bracket, the transmitting circuit board is installed on the rear side of the transmitting bracket away from the receiving bracket, and the laser emitter group is located on both sides of the front end of the transmitting circuit board; the front end of the transmitting bracket has a hollow structure, the transmitting optical components are located in the hollow structure, and at least one groove is provided on the inner wall of the hollow structure of the transmitting bracket for fixing the transmitting optical components; a light shield is provided on the side of the hollow structure away from the receiving bracket.

[0011] According to the above technical solution, the receiving optical component includes two receiving mirrors located in the middle section of the receiving cavity and multiple receiving filters located at the rear end of the receiving cavity. The two receiving mirrors are arranged in parallel, one in front of the other. The number of receiving filters is the same as the number of photodetectors, and one receiving filter is fixedly set in front of the receiving path of each photodetector.

[0012] According to the above technical solution, the receiving optical component also includes a wedge prism, which is installed at the front port of the receiving cavity for compensation of the near-end detection blind zone.

[0013] Secondly, the multi-line lidar includes a ranging unit as described above, stacked vertically, and a driving unit; the driving unit includes a motor housing, a motor base, and a motor assembly, the motor assembly being installed between the motor housing and the motor base to drive the motor housing to rotate on the motor base; the ranging unit is fixedly installed on the top of the motor housing, and the motor assembly drives the ranging unit to rotate through the motor housing to achieve a horizontal 360° panoramic scan.

[0014] According to the above technical solution, the multi-line lidar also includes a wireless power transmission unit for transmitting electrical energy, a wireless communication unit for communication, and a photoelectric encoder.

[0015] The present invention has the following beneficial effects: 1. The receiving and transmitting channels are arranged parallel to each other, both tilted at a certain angle to the horizontal. By arranging the transmitting and receiving optical components in parallel channels, the outgoing direction of the probe beam and the incident direction of the echo beam can be made approximately parallel. The structural arrangement of each optical component is relatively simple, reducing or eliminating the alignment and adjustment process. In addition, based on the parallel arrangement of the receiving and transmitting channels, the design of both the transmitting and receiving optical components has been simplified, achieving beam shaping and transmission / reception functions with as few mirrors as possible.

[0016] 2. The laser beam emitted by the optical components inside the hollow cavity is blocked by a light-shielding plate to prevent the emitted detection beam from being scattered into the radar cavity and received by the receiving module.

[0017] 3. The area illuminated by a point light source after being shaped by the transmitting optics corresponds to the receiving field of view of multiple detection units on the photodetector. This makes the receiving field of view of each line smaller than the transmitting field of view, eliminating the need for alignment of the receiving and transmitting light paths in multi-line lidar, simplifying the manufacturing process and effectively improving manufacturing efficiency. 4. Use a light-blocking plate to prevent the probe beam emitted from the light-emitting tube from entering the receiving cavity after being reflected by the optical cover, thus avoiding interference with the echo beam received by the receiving channel.

[0018] 5. A wedge prism is added, and an optical element for near-end blind spot compensation is set at the receiving end. By deflecting the echo light at a large angle near the end into the receiving field of view, the near-end detection blind zone is reduced.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention.

[0021] Figure 1 This is a structural diagram of the main body of the lidar provided in an embodiment of the present invention (the light-blocking plate is not shown). Figure 2 This is a structural diagram of the ranging unit provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the transmitting device and the receiving device provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the transmitting optical component provided in an embodiment of the present invention; Figure 5 This is a structural diagram of the receiving module provided in an embodiment of the present invention; Figure 6 This is a top view of the receiving module provided in an embodiment of the present invention; Figure 7 yes Figure 6 Sectional view of AA; In the diagram, 1-transmitting module, 101-transmitting bracket, 102-transmitting circuit board, 103-laser emitter, 104-fast-axis collimating lens, 105-slow-axis collimating lens, 106-transmitting filter, 107-deflecting and expanding lens, 108-light output tube, 109-light shield; 2-receiving module, 201-receiving bracket, 202-receiving circuit board, 203-photodetector, 204-receiving mirror, 205-receiving filter, 206-wedge prism, 207-light shield; 3-core board; 4-drive unit, 401-motor housing, 402-motor circuit board, 403-motor base; 5-wireless power transmission unit, 501-first wireless power transmission housing, 502-second wireless power transmission housing; 6-main control board Detailed Implementation The following is in conjunction with the appendix Figure 1-7 The principles and features of the present invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0022] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] Reference Figures 1-7 As shown, the ranging unit provided by the present invention includes a transmitting module 1 and a receiving module 2; The transmitting module includes a transmitting bracket 101, on which a transmitting circuit board 102, a laser emitter group 103, transmitting optical components 104 / 105 / 106 / 107 and a light-emitting tube 108 are arranged sequentially along the laser emission direction, and the transmitting optical components form a transmitting channel; The receiving module includes a receiving bracket 201, within which a receiving cavity that gradually expands from front to back is provided for the passage of the echo beam. The receiving cavity has a front port and a rear port, and the laser reflected from the object under test enters through the front port. Along the laser incident direction, receiving optical components 204 / 205 / 206 and a photodetector 203 are arranged sequentially on the receiving cavity, and the receiving optical components constitute the receiving channel. A receiving circuit board 202 electrically connected to the photodetector is provided at the rear port of the receiving cavity. The transmitting bracket and the receiving bracket are fixedly connected; the receiving channel and the transmitting channel are set in parallel and tilted at a set angle to the horizontal direction.

[0025] In the above structure, the receiving channel and the transmitting channel are arranged parallel to each other, both tilted at a certain angle to the horizontal direction. By arranging the transmitting and receiving optical components in parallel channels, the outgoing direction of the probe beam and the incident direction of the echo beam can be made approximately parallel. The structural arrangement of each optical component is relatively simple, reducing or eliminating the alignment and adjustment process of the optical path. In addition, based on the parallel arrangement of the receiving and transmitting channels, the design of both the transmitting and receiving optical components has been simplified, achieving beam shaping and transmission / reception functions with as few mirrors as possible.

[0026] Example 2 Based on Embodiment 1, a light-blocking plate 207 is provided between the transmitting bracket and the receiving bracket, located between the light-emitting tube and the front port of the receiving cavity. The light-blocking plate blocks the probe beam emitted from the light-emitting tube from entering the receiving cavity after being reflected by the optical cover, thus avoiding interference with the echo beam received by the receiving channel.

[0027] In embodiments 1 and 2, the laser emitter group is provided in two groups, each group containing several laser emitters, and each laser emitter corresponds to multiple point light sources; for example, in this embodiment there are two groups of laser emitters, each group has 4 laser emitters, and each laser emitter corresponds to 8 point light sources, so it is 64-line emission. If each laser emitter corresponds to 12 or 16 point light sources, it corresponds to 96-line or 128-line radar.

[0028] The two sets of laser emitters are arranged in an alternating vertical arrangement; or, each laser emitter in one set is arranged alternately with the laser emitters in the other set.

[0029] In embodiments 1 and 2, the emitting optical components include collimating lens groups 104 / 105, an emitting filter 106, and a deflecting and expanding mirror 107 arranged sequentially along the laser emission direction. There are multiple collimating lens groups, the number of which is the same as the number of laser emitter groups. One collimating lens group is positioned along the optical path of the probe beam emitted by each laser emitter group. Each collimating lens group includes a fast-axis collimating lens and a slow-axis collimating lens arranged sequentially along the laser emission direction. As shown in the embodiment, both the number of collimating lens groups and the number of laser emitter groups are two, with the two collimating lens groups located along the optical paths of the probe beams emitted by the two laser emitters, respectively.

[0030] The combination of fast-axis and slow-axis collimating lenses allows for adjustment of the beam divergence angle in both the fast and slow axes, enabling omnidirectional beam shaping.

[0031] In embodiments 1 and 2, multiple photodetectors are disposed on a receiving circuit board, and each photodetector includes several detection units; the photodetectors and laser emitter groups correspond one-to-one; or one photodetector corresponds to multiple laser emitter groups; or multiple photodetectors correspond to one laser emitter group.

[0032] The area illuminated by a point light source after being shaped by the transmitting optical component corresponds to the receiving field of view of multiple detection units, making the receiving field of view of each line smaller than the transmitting field of view. This eliminates the need for aligning the receiving and transmitting light paths in multi-line lidar, simplifies the manufacturing process of the lidar, and can effectively improve manufacturing efficiency.

[0033] In embodiments 1 and 2, the transmitting bracket is fixed to one side of the receiving bracket, and the transmitting circuit board is installed on the rear side of the transmitting bracket away from the receiving bracket. The laser emitter assembly is located on both sides of the front end of the transmitting circuit board. The front end of the transmitting bracket has a hollow structure, and the transmitting optical assembly is located inside the hollow structure. At least one groove is provided on the inner wall of the hollow structure of the transmitting bracket for fixing the transmitting optical assembly. A light-shielding plate 109 is provided on the side of the hollow structure away from the receiving bracket. The light-shielding plate blocks the laser beam emitted by the transmitting optical assembly inside the hollow cavity, preventing the emitted detection beam from being scattered into the radar cavity and received by the receiving module.

[0034] In embodiments 1 and 2, the receiving optical component is located on the optical path of the echo beam received by the photodetector. The receiving optical component includes two receiving mirrors 204 located in the middle section of the receiving cavity and multiple receiving filters 205 located at the rear end of the receiving cavity. The two receiving mirrors are arranged in parallel one in front of the other and are fixed by grooves on the inner wall of the receiving bracket. The number of receiving filters is the same as the number of photodetectors. One receiving filter is fixed in front of the receiving path of each photodetector. The photodetectors are fixed on the receiving circuit board by the filter bracket.

[0035] Preferably, the receiving optical assembly also includes a wedge prism 206, which is installed at the front port of the receiving cavity for compensating for near-end detection blind spots. A mounting slot is pre-set at the front end of the receiving cavity, relatively close to the transmitting module, and a wedge prism is installed thereto. This reduces the near-end detection blind spot by deflecting the large-angle echo light from the near end into the receiving field of view.

[0036] When the lidar is working, the detection beam emitted by the laser emitter passes through a collimating lens group to compress the light spot, an emission filter to filter out stray light, and a deflecting and expanding lens to deflect and amplify the beam before exiting through the light outlet tube into the space to be measured. The echo beam is incident on the front port of the receiving cavity, and passes through a receiving mirror to converge, a receiving filter to filter out stray light, and is then received by a photodetector.

[0037] The present invention also provides a multi-line lidar, including a ranging unit as described above, stacked vertically, and a driving unit 4; the driving unit includes a motor housing 401, a motor base 403, and a motor assembly (not shown in the figure), the motor assembly is installed between the motor housing and the motor base, and is used to drive the motor housing to rotate on the motor base; the ranging unit is fixedly installed on the top of the motor housing, and the motor assembly drives the ranging unit to rotate through the motor housing to achieve a horizontal 360° panoramic scan.

[0038] The multi-line lidar also includes a wireless power transmission unit 5 for transmitting electrical energy, a wireless communication unit for communication, and a photoelectric encoder. The wireless power transmission unit, the wireless communication unit, and the photoelectric encoder are all common existing structures. The following is a certain existing structural form used in this application, but other existing structural forms can also be used.

[0039] The wireless power transmission unit includes a first wireless power transmission coil (not shown in the figure), a first wireless power transmission housing 501, a second wireless power transmission coil (not shown in the figure), and a second wireless power transmission housing 502. The first wireless power transmission housing is connected to the motor base via a motor circuit board 402, and the second wireless power transmission housing is connected to the motor housing. Both the first and second wireless power transmission housings are annular and arranged around the motor assembly. The surface wall of the first wireless power transmission housing facing the motor housing has a first annular groove, in which the first wireless power transmission coil is disposed; the surface wall of the second wireless power transmission housing facing the motor base has a second annular groove, in which the second wireless power transmission coil is disposed. The first and second wireless power transmission coils are arranged opposite each other, and through their cooperation, the electrical energy on the motor base is transferred to the motor housing, supplying power to the ranging unit on the motor housing. Both the first and second wireless power transmission housings are made of a material capable of shielding magnetic field lines to prevent the magnetic field generated by the wireless power transmission coils from overflowing and affecting the power transmission efficiency. This invention places the wireless power transmission unit on the periphery of the motor assembly, which not only increases the diameter of the wireless power transmission coil and thus improves the power transmission efficiency, but also reduces the axial height of the radar.

[0040] The lidar also includes a wireless communication unit, which includes a first communication module and a second communication module. The first communication module is electrically connected to the core board, and the second communication module is electrically connected to the main control board 6.

[0041] The lidar also includes a photoelectric encoder, which comprises a code disk connected to the motor base and a code disk reader connected to the motor housing. The code disk reader rotates together with the ranging unit, and the transmitting module emits light regularly driven by the code disk signal. A high linear density code disk is selected to ensure ultra-fine scanning with a lateral scanning angular resolution of <0.1°.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A ranging unit, comprising a transmitting module and a receiving module; characterized in that: The transmitting module includes a transmitting bracket, on which a transmitting circuit board, a laser emitter group, a transmitting optical component and a light-emitting tube are arranged sequentially along the laser emission direction, and the transmitting optical component forms the transmitting channel; The receiving module includes a receiving bracket, within which a receiving cavity gradually expands from front to back. The receiving cavity has a front port and a rear port. The laser reflected by the object under test enters through the front port. Along the laser incident direction, receiving optical components and a photodetector are arranged sequentially on the receiving cavity. The receiving optical components form a receiving channel. A receiving circuit board electrically connected to the photodetector is located at the rear port of the receiving cavity. The transmitting bracket and the receiving bracket are fixedly connected; the receiving channel and the transmitting channel are set in parallel and tilted at a set angle to the horizontal direction.

2. The ranging unit according to claim 1, characterized in that: A light-blocking plate is provided between the transmitting bracket and the receiving bracket, and the light-blocking plate is located between the light-emitting tube and the front port of the receiving cavity.

3. The ranging unit according to claim 1, characterized in that: The laser emitter group is provided in two groups, each group containing several laser emitters, and each laser emitter corresponding to multiple point light sources. The two sets of laser emitters are arranged in an alternating vertical arrangement; or, each laser emitter in one set is arranged alternately with the laser emitters in the other set.

4. The ranging unit according to any one of claims 1-3, characterized in that: The emitting optical components include a collimating lens group, an emitting filter, and a deflecting and expanding mirror arranged sequentially along the laser emission direction. There are multiple collimating lens groups, and the number of collimating lens groups is the same as the number of laser emitter groups. A collimating lens group is provided in the optical path of the detection beam emitted by each laser emitter group. Each collimating lens group includes a fast-axis collimating lens and a slow-axis collimating lens arranged sequentially along the laser emission direction.

5. The ranging unit according to claim 1, characterized in that: Multiple photodetectors are mounted on the receiving circuit board, and each photodetector contains several detection units; There is a one-to-one correspondence between photodetectors and laser emitter groups; or one photodetector corresponds to multiple laser emitter groups; or multiple photodetectors correspond to one laser emitter group.

6. The ranging unit according to claim 1, characterized in that: The transmitting bracket is fixed to one side of the receiving bracket. The transmitting circuit board is installed on the rear side of the transmitting bracket away from the receiving bracket. The laser emitter group is located on both sides of the front end of the transmitting circuit board. The front end of the transmitting bracket has a hollow structure. The transmitting optical components are located inside the hollow structure. At least one groove is provided on the inner wall of the hollow structure of the transmitting bracket for fixing the transmitting optical components. A light shield is provided on the side of the hollow structure away from the receiving bracket.

7. The ranging unit according to claim 1, characterized in that: The receiving optical assembly includes two receiving mirrors located in the middle of the receiving cavity and multiple receiving filters located at the rear end of the receiving cavity. The two receiving mirrors are arranged in parallel, one in front of the other. The number of receiving filters is the same as the number of photodetectors, and one receiving filter is fixedly placed in front of the receiving path of each photodetector.

8. The ranging unit according to claim 7, characterized in that: The receiving optical assembly also includes a wedge prism, which is installed at the front port of the receiving cavity for compensation of near-end detection blind spots.

9. A multi-line lidar, characterized in that: It includes a ranging unit as described in any one of claims 1-8, which are stacked vertically, and a driving unit; the driving unit includes a motor housing, a motor base, and a motor assembly, wherein the motor assembly is installed between the motor housing and the motor base and is used to drive the motor housing to rotate on the motor base; The ranging unit is fixedly mounted on the top of the motor housing, and the motor assembly drives the ranging unit to rotate through the motor housing to achieve a 360° horizontal panoramic scan.

10. The multi-line lidar according to claim 9, characterized in that: The multi-line lidar also includes a wireless power transmission unit for transmitting electrical energy, a wireless communication unit for communication, and a photoelectric encoder.

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