Multi-line laser radar rotating mirror scanning system

Abstract

The invention discloses a multi-line laser radar rotating mirror scanning system, which belongs to the technical field of laser detection and solves the problems of difficulty in three-dimensional space scanning, low scanning precision and short service life in the prior art. The multi-line laser radar rotating mirror scanning system comprises a laser transmitting module, a control module and a rotating mirror structure, a collimating mirror and a first reflecting mirror are sequentially arranged at the rear end of the laser light source in the light direction, the first reflecting mirror is used for vertically reflecting shaped laser beams to the second reflecting mirror, and a rotating mirror structure is arranged at the bottom of the first reflecting mirror. The rotating mirror structure is arranged on the surface of the rotating disc, the mechanical structure of the rotating mirror is simplified, the weight is reduced, the service life of the whole radar system is prolonged, the rotating mirror structure and the control module are used in cooperation, radar light beams are radiated in the maximum range, the collection range is expanded to 180 degrees, three-dimensional space point cloud different from a two-dimensional space is established, and the detection accuracy is improved. And the laser radar scanning precision is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser detection, and more particularly, to a multi-line lidar rotating mirror scanning system. Background Art

[0002] Lidar is increasingly widely used in the fields of intelligent driving, surveying and mapping, robotics, artificial intelligence, etc. With the rapid development of intelligent connected vehicles, lidar, as the core sensor for assisted driving, has an irreplaceable position, and its accurate grasp of the surrounding environment has become the core element for safe driving. After three stages of development, namely mechanical, solid-state, and hybrid solid-state, the core structure of lidar still consists of a laser light source and a mirror group. Among them, the scanning system of lidar is composed of a motor and multiple mirror groups in combination, which is a key component of lidar.

[0003] A laser scanning lidar forms a scanning cross-section by rotating and scanning the emitted laser beam, so as to test the characteristic information of the object to be measured. Although traditional mechanical rotary lidar can scan the surrounding area to a certain extent, the complex mechanical structure brings high failure rate and low efficiency, making it difficult to meet the ever-changing perception needs of high-speed vehicles. Single-line lidar mostly adopts a two-dimensional scanning method. Due to the limitation of dimensions, it cannot provide sufficient information for judging complex road conditions.

[0004] The multi-line lidar rotating mirror scanning system effectively integrates advantages. By designing its rotating mirror and simplifying the mechanical structure, the risk of failure is reduced. At the same time, through the mirror group, the multi-line emission and reception functions are used to construct a fine three-dimensional point cloud, accurately capturing the details of objects at different heights in scenarios such as intersections with mixed pedestrians and vehicles, ensuring the accuracy of autonomous driving decisions. Patent 201810207854.5 discloses a three-dimensional scanning lidar based on a MEMS micromirror, including a base, a scanning module, a control module, a transmitting module, and a receiving module. The scanning module performs a 360° rotational scan in the horizontal direction and provides the angular orientation in the horizontal direction. Although this application can achieve a 360° rotational scan, due to the small size of the MEMS galvanometer mirror, its mechanical structure is relatively fragile, and in a long-term and high-intensity vibration or impact environment, mechanical damage problems such as mirror surface deformation and cantilever beam fracture are likely to occur, thereby affecting the reflection accuracy of the laser beam and reducing the reliability of the entire lidar system. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-line lidar rotating mirror scanning system that can achieve three-dimensional space scanning, has high scanning accuracy, and a long service life in view of the deficiencies of the existing technology.

[0006] In order to achieve the above technical purpose, the technical solution adopted by the multi-line lidar rotating mirror scanning system of the present invention is as follows: A multi-line laser radar rotating mirror scanning system comprises a laser emission module, a control module and a rotating mirror structure, wherein the laser module comprises a laser light source for emitting a laser beam, wherein a collimator and a first reflector are sequentially arranged at the rear end of the laser light source along the direction of the light, wherein the collimator is used to shape the laser beam, wherein the first reflector is used to vertically reflect the shaped laser beam to a second reflector, wherein the second reflector is used to emit the laser beam, wherein a rotating mirror structure is arranged at the bottom of the first reflector, wherein the rotating mirror structure comprises a rotating disk for receiving the first reflector, wherein a pad for supporting the first reflector is arranged between the surface of the rotating disk and the back of the first reflector, wherein rotating disk support structures are arranged at both ends of the rotating disk, wherein a first motor is arranged on the inner side of the upper part of the rotating disk support structure, wherein a rotating shaft is connected to the output end of the first motor, wherein a second reflector is passed through the surface of the rotating shaft, wherein a control module for driving the rotating disk to rotate is arranged at the bottom of the rotating disk, wherein the control module comprises a second motor coaxially connected to the bottom of the rotating disk, and wherein the second motor is electrically connected to a driving circuit.

[0007] Preferably, the rotating mirror structure is arranged above the control module, and the laser emission module is arranged on the side of the rotating mirror structure.

[0008] Preferably, the first reflector and the second reflector are arranged in parallel, and the second reflector is arranged above the first reflector.

[0009] Preferably, the first motor and the second motor rotate synchronously at high speed.

[0010] Compared with the prior art, the present invention has the following beneficial effects: The present invention arranges a rotating mirror structure on the surface of a rotating disk, simplifies the mechanical structure of the rotating mirror, reduces weight, and prolongs the service life of the entire radar system; the rotating mirror structure and the control module are used in coordination to radiate the radar light beam in the maximum range, expand the collection range to 180°, and establish a three-dimensional space point cloud different from the two-dimensional space, thereby avoiding the problem of a rotating disk carrying a laser transmitting device and a receiving device simultaneously rotating 360° at a high speed in the conventional scanning technology, which increases the time interval for the second scanning of a relative space and the problem of only being able to perform plane scanning; the rotating mirror structure can select reflectors of different sizes according to the type of radar, and is not limited by the number of laser radar lines, thereby avoiding the problem of mechanical deformation caused by the conventional use of MEMS mirrors due to their tiny structure after adjusting the light beam under vibration in the X-axis and Y-axis directions, resulting in a decrease in the scanning accuracy of the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of a laser radar scanning method in the prior art; Figure 2 It is a schematic diagram of laser radar scanning based on MEMS micromirror in the prior art; Figure 3It is a schematic structural diagram of the present invention; Figure 4 It is a schematic structural diagram of the rotating mirror structure of the present invention.

[0012] In the figure: 1. Laser light source; 2. Collimating mirror; 3. First reflector; 4. Second reflector; 5. Rotating disk; 6. Spacer block; 7. Rotating disk support structure; 8. First motor; 9. Rotating shaft; 10. Second motor; 11. Driving circuit. Specific embodiments

[0013] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments: As Figure 1 shown, the existing lidar scanning method mainly uses traditional two-dimensional mechanical scanning. The disk carrying the laser emission and reception devices is driven by a motor to rotate at high speed by 360° around the vertical axis, which can achieve all-round two-dimensional plane scanning of the surrounding environment to cover the surrounding environment. However, in this method, the lidar needs to be driven by a mechanical structure, and the complexity of the mechanical structure is the primary drawback. A large number of rotating components and transmission mechanisms not only occupy a large amount of space, making the entire lidar device bulky and unable to be effectively applied in some scenarios with strict space requirements. For example, it is difficult to be adapted for small unmanned aerial vehicle carrying due to weight and space limitations. At the same time, frequent mechanical movements are likely to cause component wear, increase the equipment failure rate, and the maintenance cost is high. It is necessary to regularly replace worn components and calibrate mechanical accuracy, etc., which is not conducive to long-term use. In addition, in terms of scanning speed, limited by the physical characteristics of mechanical rotation, there is a large time interval for collecting spatial point clouds of relative positions for 360°, and its scanning speed is relatively slow. In the face of dynamically changing scenarios quickly, such as monitoring the surrounding environment of a vehicle traveling at high speed, it is difficult to capture the rapidly changing information in time, and data lag is likely to occur, affecting the judgment of the real-time situation of the environment. Third, since it is two-dimensional scanning, only plane information can be obtained, and it is difficult to accurately detect details such as the height of objects in the vertical direction. In complex three-dimensional scene applications, such as in urban streets where there are both vehicles and pedestrians, as well as buildings and street lamp poles of different heights, it cannot provide comprehensive and accurate three-dimensional perception, restricting its in-depth application in higher-level autonomous driving, high-precision three-dimensional mapping and other fields.

[0014] As Figure 2As shown, the core structure of the laser radar scanning based on MEMS galvanometer can be a movable mirror, which swings the laser beam in the X-axis and Y-axis directions through the motor micro-electromechanical system, so that the direction of the incident laser beam changes accordingly, thereby realizing spatial scanning of the target. However, due to the small size of the MEMS galvanometer, its mechanical structure is relatively fragile. Under long-term, high-intensity vibration or impact environment, it is easy to have mechanical damage problems such as mirror deformation and cantilever beam breakage, which in turn affects the reflection accuracy of the laser beam and reduces the reliability of the entire laser radar system. In addition, the MEMS galvanometer is usually limited by its own structure and driving mode, and the scanning angle range is relatively narrow. In some scenarios that require large-area, no-dead-angle perception, such as environmental monitoring of large storage and logistics centers, it is difficult to meet the needs, resulting in some areas becoming scanning blind spots, resulting in a decrease in the accuracy of the entire laser radar scanning.

[0015] like Figure 3 — Figure 4 As shown, a multi-line laser radar rotating mirror scanning system includes a laser emission module, a control module and a rotating mirror structure, wherein the rotating mirror structure is arranged above the control module, the laser emission module is arranged on the side of the rotating mirror structure, the laser module includes a laser light source 1 for emitting a laser beam, and the laser light source 1 is provided with a collimator 2 and a first reflector 3 in sequence at the rear end along the direction of the light, the collimator 2 is used to shape the laser beam, the first reflector 3 is used to vertically reflect the shaped laser beam to the second reflector 4, the first reflector 3 and the second reflector 4 are arranged in parallel, and the second reflector 4 is arranged above the first reflector 3, and the second reflector 4 is used to Beam emission, a rotating mirror structure is provided at the bottom of the first reflector 3, the rotating mirror structure includes a rotating disk 5 that supports the first reflector 3, a pad 6 for supporting the first reflector 3 is provided between the surface of the rotating disk 5 and the back of the first reflector 3, rotating disk supporting structures 7 are provided at both ends of the rotating disk 5, a first motor 8 is provided on the inner side of the upper part of the rotating disk supporting structure, the output end of the first motor 8 is connected to a rotating shaft 9, the surface of the rotating shaft 9 passes through a second reflector 4, a control module for driving the rotating disk 5 to rotate is provided at the bottom of the rotating disk 5, the control module includes a second motor 10 coaxially connected to the bottom of the rotating disk 5, and the second motor 10 is electrically connected to a driving circuit 11.

[0016] In the present invention, the first motor 8 and the second motor 10 rotate synchronously at high speed. By controlling the synchronous rotation of the first motor 8 and the second motor 10, the laser beam can simultaneously scan the X-axis and the Y-axis, solving the problem that a certain space needs to be scanned twice in the conventional technology to ensure the scanning of the X-axis and the Y-axis.

[0017] When the present invention works, the laser light source 1 emits multiple laser beams. After being shaped by the collimating mirror 2, the laser beams are irradiated onto the first reflecting mirror 3 along the light axis direction. After the first reflecting mirror 3 reflects the beams, the laser beams are irradiated onto the second reflecting mirror 4, and the second reflecting mirror 4 emits the beams outward. At the same time, the driving circuit 11 controls the second stepping motor 10 to start. The second stepping motor 10 drives the rotating disk 5 to rotate. The rotating disk 5 makes a 180° high-speed swing. Since the second reflecting mirror 4 is connected to the rotating disk 5 through the rotating disk support structure 7, the laser beams reflected by the second reflecting mirror 4 are simultaneously driven to perform a 180° scan in the X-axis direction of the space. At the same time, the first motor fixed on the rotating disk support structure makes a 180° high-speed rotation, and the laser beams received by the second reflecting mirror from the first reflecting mirror are rotated through the rotating shaft to achieve a 180° scan in the Y-axis direction of the space. The driving circuit performs algorithm control on the first motor and the second motor, and cooperates with the synchronous high-speed rotation of the first motor and the second motor to realize the acquisition of three-dimensional point clouds in the X-axis and Y-axis directions of the space in a short time, avoiding the problems in the conventional scanning technology that when the rotating disk carries the laser emitting device and the receiving device and rotates at a high speed of 360° at the same time, the time interval for the second scan of a certain relative space becomes larger, and it is a planar scan of the space and cannot effectively identify three-dimensional obstacles or application scenarios such as warehousing.

[0018] In summary, the above are only the preferred embodiments of the present invention, and are not used to limit the scope of implementation of the present invention. All equivalent changes and modifications made according to the shape, structure, features and spirit of the scope of the claims of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A multi-line laser radar rotating mirror scanning system, comprising a laser emission module, a control module and a rotating mirror structure, wherein the laser module comprises a laser light source for emitting a laser beam, and is characterized in that: The laser light source is provided with a collimator and a first reflector in sequence at the rear end along the light direction, the collimator is used to shape the laser beam, the first reflector is used to vertically reflect the shaped laser beam to the second reflector, and the second reflector is used to emit the laser beam, a rotating mirror structure is provided at the bottom of the first reflector, the rotating mirror structure includes a rotating disk that supports the first reflector, a pad for supporting the first reflector is provided between the surface of the rotating disk and the back of the first reflector, a rotating disk support structure is provided at both ends of the rotating disk, a first motor is provided on the inner side of the upper part of the rotating disk support structure, a rotating shaft is connected to the output end of the first motor, a second reflector passes through the surface of the rotating shaft, a control module for driving the rotating disk to rotate is provided at the bottom of the rotating disk, the control module includes a second motor coaxially connected to the bottom of the rotating disk, and the second motor is electrically connected to the driving circuit.

2. The multi-line laser radar rotating mirror scanning system according to claim 1, characterized in that: The rotating mirror structure is arranged above the control module, and the laser emission module is arranged on the side of the rotating mirror structure.

3. The multi-line laser radar rotating mirror scanning system according to claim 1, characterized in that: The first reflector and the second reflector are arranged in parallel, and the second reflector is arranged above the first reflector.

4. The multi-line laser radar rotating mirror scanning system according to claim 1, characterized in that: The first motor and the second motor rotate synchronously at high speed.

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