A design method for a continuous rotating cylindrical laser radar galvanometer for autonomous driving vehicles

Abstract

The present invention belongs to the field of laser scanning, and specifically relates to a design method for a continuous rotating cylindrical self-driving car laser radar galvanometer, including: establishing a laser irradiation spiral line; obtaining the normal vectors of all reflection points on the laser irradiation spiral line by calculating the position of the laser and the corresponding angle to be scanned; constructing a spiral reflection surface according to the positions of all reflection points on the laser irradiation spiral line and their normal vectors, and winding a spiral reflection mirror along the spiral reflection surface. The normal vector of each reflection point of the laser irradiation spiral line in the galvanometer designed by the present invention is designed separately, thus solving the problem of deformation of the traditional galvanometer scanning.

Description

Technical Field

[0001] The present invention belongs to the field of laser scanning, and in particular relates to a design method for a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle. Background Art

[0002] Since the 21st century, with the development of the Internet of Things, integrated circuits and artificial intelligence, unmanned driving technology has become an important part of the field of smart cars. The key to the realization of this technology is to accurately perceive the environment around the car, and obstacle detection technology plays a fundamental and decisive role in environmental perception. Therefore, in-depth research on obstacle measurement methods is of great significance to the development of unmanned driving technology.

[0003] Commonly used means of detecting vehicle obstacles include high-precision camera systems, millimeter-wave radars, and laser radars. Laser radar uses laser signals of a specific wavelength to actively scan the surface of obstacles to obtain information about the obstacle surface. Therefore, it is not easily affected by ambient light, has strong anti-interference capabilities, has good directionality and coherence, and can achieve high-precision measurements. Therefore, laser radar technology has obvious advantages in obstacle detection and environmental reconstruction. When measuring, scanning laser radar is generally used to measure obstacles in two or three dimensions. Its detection mechanism is mainly to use laser as a radiation source to perform high-precision distance measurement on the target obstacle, so that the vehicle can avoid obstacles in a timely and effective manner.

[0004] At present, the research on LiDAR applied to driverless cars is mainly based on scanning LiDAR, which uses pulse laser ranging as the main obstacle detection method. However, it generally has the disadvantages of high R&D cost, complex system, and difficulty in improving measurement accuracy, and poor system stability. Therefore, on this basis, it is of great significance to study and design a low-cost, highly integrated LiDAR system that can achieve high-precision measurement for the development of driverless technology. The key component that affects the performance of scanning LiDAR is the galvanometer used for scanning. The existing galvanometer is a reciprocating vibrating plane reflector. This structure has extremely high requirements on motor accuracy and poor stability. Due to the limitations of the galvanometer motion characteristics, the scanning field will be deformed to a certain extent. Summary of the invention

[0005] In order to make up for the deficiencies of the prior art, the present invention provides a technical solution for a design method of a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle.

[0006] A design method for a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle, comprising:

[0007] S100 establishes the laser irradiation spiral;

[0008] S200 obtains the normal vectors of all reflection points on the laser irradiated spiral line by calculating the position of the laser and the corresponding scanning angle;

[0009] S300 constructs a spiral reflection surface according to the positions of all reflection points on the laser irradiated spiral line and their normal vectors, and arranges a spiral reflection mirror along the spiral reflection surface.

[0010] Furthermore, in S200, the normal vector design of each reflection point in the galvanometer meets requirement R1: each reflection point of the laser irradiation spiral has a normal vector, a laser irradiation position is set, and the normal vector of the reflection point when it is at the laser irradiation position is set as the irradiation normal vector. There are at least four irradiation normal vectors in different directions among all the reflection points on the laser irradiation spiral, so that when the galvanometer is irradiated by the laser in the working state, the reflected scanning points are arranged in an array.

[0011] Furthermore, in the requirement R1, the directions of the irradiation normal vectors of all reflection points on the laser irradiation spiral line are different.

[0012] Furthermore, in S100, the laser irradiated helix is ​​designed to be a helix with equal diameter and equal pitch.

[0013] Furthermore, in S300, adjacent circles of the spiral reflector are closely arranged, so that the spiral reflector forms a cylindrical mirror surface.

[0014] Furthermore, the operation of S300 also includes providing a support body, and winding the spiral reflector around the surface of the support body.

[0015] Furthermore, the support body is a cylindrical structure.

[0016] Furthermore, in S200, the method for calculating the normal vector of each reflection point includes:

[0017] The illumination normal vector N of the reflection point is calculated according to formula (1), and the reflection surface of the reflection unit is obtained according to the illumination normal vector N of the reflection unit.

[0018]

[0019] Wherein, vector I represents the incident laser direction, vector R represents the outgoing laser direction, and vector I and vector R are obtained according to the position of the laser, the reflection point and the scanning point.

[0020] Furthermore, the design method further includes S400, which includes: designing the rotation angular velocity of the galvanometer, the pitch of the laser irradiation helix, and the relative movement speed of the galvanometer and the laser according to formula (2),

[0021] h / v=2π / w (2)

[0022] Among them, v represents the relative movement speed between the laser and the galvanometer, w represents the angular velocity of the galvanometer, and h represents the pitch of the laser irradiated helix.

[0023] Compared with the prior art, the normal vector of each reflection point of the laser irradiation spiral line in the galvanometer designed in the present invention is designed separately, which solves the problem of deformation of traditional galvanometer scanning. At the same time, the rotation of the galvanometer can be conveniently controlled to be uniform motion, and the relative motion of the galvanometer and the laser can be conveniently controlled to be uniform motion, which can effectively solve the problem of uneven distribution of scanning points, and also makes the driving structure of the galvanometer simpler and more reliable, greatly reducing the overall manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of the present invention;

[0025] Figure 2 One of the structural schematic diagrams of the continuous rotating cylindrical self-driving car laser radar galvanometer designed for the present invention when used in conjunction with a laser;

[0026] Figure 3 The second structural diagram of the continuous rotating cylindrical self-driving car laser radar galvanometer designed for the present invention when used in conjunction with the laser;

[0027] Figure 4 A schematic diagram of the optical path when a reflection point in the continuous rotating cylindrical self-driving car laser radar galvanometer designed by the present invention is irradiated by laser;

[0028] Figure 5 Schematic diagram of the laser scanning dot matrix when the continuous rotating cylindrical autonomous driving car laser radar galvanometer designed for the present invention is in use.

[0029] In the figure: 1 is a spiral reflector; 100 is a laser irradiation spiral line; 2 is a laser irradiation position; 3 is a support body; 4 is a laser; n is the number of turns of a reflection unit group; m is the number of reflection units in a single reflection unit group; R is the incident laser direction; I is the outgoing laser direction; and N is the irradiation normal vector. DETAILED DESCRIPTION

[0030] In the description of the present invention, it is necessary to understand that the terms "one end", "the other end", "outside", "upper", "inside", "horizontal", "coaxial", "center", "end", "length", "outer end" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] See also Figure 1-5 , a design method for a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle, comprising:

[0033] S100 establishes laser irradiation helix 100;

[0034] S200 obtains the normal vectors of all reflection points on the laser irradiated spiral line 100 by calculating the position of the laser 4 and the corresponding angle to be scanned;

[0035] S300 constructs a spiral reflection surface according to the positions of all reflection points on the laser irradiated spiral line 100 and their normal vectors, and arranges a spiral reflection mirror 1 along the spiral reflection surface;

[0036] S400 designs the angular velocity of the galvanometer, the pitch of the laser irradiation helix, and the relative movement speed of the galvanometer and the laser according to formula (2).

[0037] h / v=2π / w (2)

[0038] Wherein, v represents the relative moving speed between the laser 4 and the galvanometer, w represents the angular velocity of the galvanometer, and h represents the pitch of the laser irradiated helix.

[0039] The above design method first uses computer modeling software and its corresponding calculation program to establish a three-dimensional model, and then manufactures a solid galvanometer based on the three-mode model.

[0040] Furthermore, in S200, the normal vector design of each reflection point in the galvanometer meets requirement R1: each point of the laser irradiation spiral line 100 is a reflection point, and each reflection point has a normal vector. A laser irradiation position 2 is set, and the laser irradiation position 2 represents the position where the laser 4 irradiates the spiral reflector 1. The galvanometer can make each reflection point on the laser irradiation spiral line 100 reach the laser irradiation position 2 by rotating and moving up and down relative to the laser 4. The normal vector when the reflection point is at the laser irradiation position 2 is set as the irradiation normal vector. Among all the reflection points on the laser irradiation spiral line 100, there are at least four irradiation normal vectors with different directions, so that when the galvanometer is irradiated by the laser 4 in the working state, the reflected scanning points are arranged in an array.

[0041] Preferably, in the requirement R1, the directions of the irradiation normal vectors of all reflection points on the laser irradiation helix 100 are different.

[0042] It can be understood that such a design makes all emission points of the galvanometer correspond to one scanning point, and the scanning effect is better.

[0043] Furthermore, in the S100, the laser irradiated helix 100 is designed to be a helix with equal diameter and equal pitch.

[0044] It can be understood that the helical lines with equal diameter and equal pitch are more regular, which is convenient for the design and manufacture of the galvanometer.

[0045] Furthermore, in S200, the method for calculating the normal vector of each reflection point includes:

[0046] The illumination normal vector N of the reflection point is calculated according to formula (1), and the reflection surface of the reflection unit is obtained according to the illumination normal vector N of the reflection unit.

[0047]

[0048] Wherein, vector I represents the incident laser direction, vector R represents the outgoing laser direction, and vector I and vector R are obtained according to the position of the laser, the reflection point and the scanning point.

[0049] Further to S200: The present invention obtains the normal vector of each reflection point on the laser irradiation spiral line 100 by calculating the position of the laser 4 and the corresponding angle to be scanned, and finally obtains the continuously changing free reflection surface of the spiral reflector 1 by fitting these points. Specifically, the direction of the normal vector of the reflection point on the mirror surface is obtained by calculating the position of the laser 4 and the corresponding angle to be scanned, and all reflection points are obtained by such calculation method.

[0050] Furthermore, the operation of S300 further includes providing a support body 3, which is preferably a cylindrical structure, and winding the spiral reflector 1 on the surface of the support body 3. The spiral reflector 1 can be a whole reflective plane mirror, which can be fixedly attached to the surface of the support body 3.

[0051] Furthermore, in the above S300, the adjacent circles of the spiral reflector 1 are closely arranged, and there is no gap between the adjacent circles, that is, the width of each circle of the spiral reflector 1 is equal to its pitch, so that the entire spiral reflector 1 constitutes an integral cylindrical mirror surface. In addition, the width of each circle of the spiral reflector 1 can also be designed to be smaller than the pitch, so that gaps are formed between different circles of the spiral reflector 1.

[0052] Further explanation of S400: Such a design enables the laser light emitted by the laser 4 to move relatively along the laser irradiation spiral line 100.

[0053] When the galvanometer designed by the present invention is used, the galvanometer rotates at a certain angular velocity, the laser 4 also emits laser at a certain frequency, and the laser 4 moves up and down at a certain speed, or the galvanometer moves up and down at a certain speed. As long as the laser 4 and the galvanometer move relatively at a uniform speed, the rotation of the galvanometer is coordinated with the movement of the laser 4. When the laser 4 emits laser, the laser can move exactly to the laser irradiation spiral line 100 of the spiral reflector 1, and the irradiation point of the laser will move relatively along the laser irradiation spiral line 100. When the irradiation normal vector direction of the reflection point is different, the laser reflection direction is also different, so the position of the scanning point is also different, all scanning points can be irradiated by the laser 4, and each reflection point can reflect a scanning point. All reflection points in this embodiment correspond to a scanning matrix, so as to achieve the deflection effect of the galvanometer.

[0054] Since the galvanometer of this embodiment can design each reflection point individually, the direction of the scanning point reflected by the reflection point can also be designed individually accordingly. Through the design, these scanning points are arranged at equal intervals when projected onto the same plane to avoid deformation.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle, characterized in that: include: S100 establishes the laser irradiation helix; S200 obtains the normal vectors of all reflection points on the laser irradiation spiral line by calculating the position of the laser and the corresponding angle to be scanned, wherein the normal vector design of each reflection point in the galvanometer satisfies the requirement R1: each reflection point of the laser irradiation spiral line has a normal vector, a laser irradiation position is set, and the normal vector of the reflection point when it is located at the laser irradiation position is set as the irradiation normal vector. There are at least four irradiation normal vectors in different directions among all reflection points on the laser irradiation spiral line, so that when the galvanometer is irradiated by the laser in the working state, the reflected scanning points are arranged in an array; S300 constructs a spiral reflection surface based on the positions and normal vectors of all reflection points on the laser irradiated spiral line, and arranges a spiral reflector along the spiral reflection surface.

2. The method for designing a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 1, characterized in that: In the requirement R1, the directions of the irradiation normal vectors of all reflection points on the laser irradiation spiral line are different.

3. A method for designing a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 1 or 2, characterized in that: In the above S100, the laser irradiated helical line is designed to be a helical line with equal diameter and equal pitch.

4. The method for designing a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 3, characterized in that: In the above S300, adjacent circles of the spiral reflector are closely arranged, so that the spiral reflector forms a cylindrical mirror surface.

5. A method for designing a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 1 or 2, characterized in that: The operation of S300 further includes providing a support body and winding the spiral reflector around the surface of the support body.

6. The method for designing a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 5, characterized in that: The support body is a cylindrical structure.

7. A method for designing a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 1 or 2, characterized in that: In S200, the method for calculating the normal vector of each reflection point includes: The illumination normal vector N of the reflection point is calculated according to formula (1), and the reflection surface of the reflection unit is obtained according to the illumination normal vector N of the reflection unit. （1） in, represents the incident laser direction, Indicates the direction of the emitted laser. and It is obtained according to the laser position, the reflection point and the scanning point.

8. A method for designing a continuous rotating cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 1 or 2, characterized in that: The design method further includes S400, which includes: designing the rotation angular velocity of the galvanometer, the pitch of the laser irradiation helix, and the relative movement speed of the galvanometer and the laser according to formula (2), h / v=2π / w (2) Among them, v represents the relative movement speed between the laser and the galvanometer, w represents the angular velocity of the galvanometer, and h represents the pitch of the laser irradiated helix.

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