A design method for a discontinuous cylindrical laser radar galvanometer for autonomous vehicles

Abstract

The present invention belongs to the field of laser scanning, and specifically relates to a method for designing a discontinuous cylindrical galvanometer for autonomous vehicle lidar. The method comprises: designing the galvanometer's basic structure into a cylindrical shape, wherein the cylindrical surface is composed of a plurality of reflective unit groups arranged from top to bottom, each reflective unit group comprising m reflective units evenly distributed and surrounding a cylindrical mirror ring, where m is a natural number greater than 1; and calculating the position of the laser and the corresponding scanning angle to obtain the normal direction of the reflective surface of each reflective unit. This calculation method is used for each reflective unit. The present invention enables the individual design of each reflective unit in the galvanometer, thereby resolving the problem of deformation caused by conventional 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 discontinuous 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 the accurate perception of 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 vehicle obstacle detection methods include high-precision camera systems, millimeter-wave radar, and lidar. LiDAR uses laser signals of a specific wavelength to actively scan the surface of obstacles to obtain surface information. Therefore, it is not susceptible to ambient light, has strong anti-interference capabilities, and has good directionality and coherence, enabling high-precision measurement. Therefore, lidar technology has significant advantages in obstacle detection and environmental reconstruction. During measurement, scanning lidar is generally used to measure obstacles in two or three dimensions. Its detection mechanism primarily uses laser as a radiation source to perform high-precision distance measurements on target obstacles, enabling vehicles to avoid obstacles in a timely and effective manner.

[0004] Currently, research on lidar for autonomous vehicles focuses on scanning lidar, using pulsed laser ranging as the primary obstacle detection method. However, these systems suffer from high R&D costs, complex systems, difficulty improving measurement accuracy, and poor system stability. Therefore, researching and designing low-cost, highly integrated lidar systems that can achieve high-precision measurements is crucial for the development of autonomous driving technology. A key component affecting the performance of scanning lidar is the scanning galvanometer. Existing galvanometers are reciprocating planar mirrors, a structure that requires extremely high motor precision and suffers from poor stability. Due to the limitations of the galvanometer's motion, the scanning field can be distorted. Summary of the Invention

[0005] In order to make up for the shortcomings of the existing technology, the present invention provides a technical solution for the design method of a discontinuous cylindrical laser radar galvanometer for autonomous driving vehicles.

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

[0007] The S100 galvanometer's basic structure is designed to be cylindrical. The cylindrical surface is composed of several circles of reflective unit groups arranged sequentially from top to bottom. Each reflective unit group includes m reflective units evenly distributed around the cylindrical mirror ring, where m is a natural number greater than 1.

[0008] S200 obtains the normal direction of the reflective surface of the reflective unit by calculating the position of the laser and the corresponding angle to be scanned. Each reflective unit is obtained by this calculation method.

[0009] Furthermore, in S200, the specific calculation method of each reflection unit is as follows:

[0010] The illumination normal vector N of the reflection unit 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.

[0011]

[0012] Wherein, vector I represents the direction of incident laser light, and vector R represents the direction of outgoing laser light. Vector I and vector R are obtained according to the position of the laser, the reflective unit, and the scanning point.

[0013] Furthermore, the design method further includes S300, which includes: designing the rotation angular velocity of the galvanometer and the emission frequency of the laser according to formula (2),

[0014] f=mw / 2π (2)

[0015] Where f is the laser emission frequency and w is the angular velocity of the galvanometer.

[0016] Furthermore, the S200 also includes: the irradiation normal vector of each reflection unit in the galvanometer is designed to meet requirement R1: a laser irradiation position is set, and the normal vector of the reflection unit 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 in all the reflection units on the galvanometer, so that when the galvanometer is in a working state and receives laser irradiation, the reflected scanning points are arranged in an array.

[0017] Furthermore, in the requirement R1, the directions of the illumination normal vectors of all the reflection units on the galvanometer are different.

[0018] Furthermore, in the requirement R1, every time the galvanometer rotates 360° / m, the next reflective unit reaches the laser irradiation position.

[0019] Furthermore, in the S100, the basic structural design of the galvanometer must meet requirement R2: the plurality of reflective unit groups are arranged at equal intervals vertically.

[0020] Furthermore, in the requirement R2, the heights of all the reflection units in the galvanometer are the same.

[0021] Furthermore, in the requirement R2, all the reflection units in the galvanometer are closely arranged.

[0022] Furthermore, the S100 further includes: designing a support body, and arranging the plurality of reflective unit groups on a surface of the support body.

[0023] Compared with the prior art, the beneficial effects of the present invention are: the present invention can design each reflection unit in the galvanometer individually, thus solving the problem of deformation of the 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 regular motion, which can effectively solve the problem of uneven distribution of the scanning point array, 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 Flowchart of the present invention;

[0025] Figure 2 Schematic diagram of the discontinuous cylindrical self-driving car laser radar galvanometer structure designed for the present invention;

[0026] Figure 3 A schematic diagram of the structure of the discontinuous cylindrical autonomous driving car lidar galvanometer designed by the present invention when combined with the laser;

[0027] Figure 4 A schematic diagram of the optical path of the reflective unit in the discontinuous cylindrical self-driving car LiDAR galvanometer designed by the present invention when it is irradiated by laser;

[0028] Figure 5 The laser scanning dot matrix when the discontinuous cylindrical autonomous driving vehicle laser radar galvanometer designed by the present invention is used.

[0029] In the figure: 1 is the reflection unit; 2 is the support body; 3 is the laser; 5 is the laser irradiation position; n is the number of circles of the 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; N is the irradiation normal vector. DETAILED DESCRIPTION

[0030] In the description of the present invention, it should be understood 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. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

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

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

[0033] S100 designs the basic structure of the galvanometer into a cylindrical shape. The cylindrical surface is composed of n circles of reflective unit groups arranged from top to bottom. Each reflective unit group includes m reflective units 1 evenly distributed around the cylindrical mirror ring. n and m are natural numbers greater than 1.

[0034] S200 calculates the position of the laser 3 and the corresponding scanning angle to obtain the normal direction of the reflective surface of the reflective unit 1. Each reflective unit is obtained by this calculation method.

[0035] S300 designs the angular velocity of the galvanometer and the emission frequency of the laser according to formula (2).

[0036] f=mw / 2π (2)

[0037] Where f is the laser emission frequency and w is the angular velocity of the galvanometer.

[0038] 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.

[0039] Furthermore, the S100 also includes: designing a cylindrical support body 2, arranging the several reflection unit groups on the surface of the support body 2, so that all the reflection units 1 are distributed on the support body 2 in a regular rectangular array. The reflection unit 1 of the present invention can be a whole reflecting plane mirror, which can be fixedly attached to the surface of the support body 2. In addition, it can also be a reflecting plane mirror with a carrier, the area of ​​the carrier is larger than the reflecting plane mirror, and it is fixedly attached to the surface of the support body 2 through the carrier.

[0040] Furthermore, in S100, the basic structural design of the galvanometer must meet requirement R2: the reflective units 1 in the plurality of reflective unit groups are positioned one-to-one, and all reflective units 1 in the galvanometer are at the same height and closely arranged. This design ensures that the plurality of reflective unit groups are evenly spaced.

[0041] Furthermore, in S200, the specific calculation method of each reflection unit 1 is as follows:

[0042] According to formula (1), the illumination normal vector N of the reflection unit 1 is calculated, and the reflection surface of the reflection unit is obtained according to the illumination normal vector N of the reflection unit 1. Each single reflection unit 1 is calculated, and then they are combined into a cylindrical whole to obtain the whole galvanometer.

[0043]

[0044] Wherein, vector I represents the direction of incident laser light, and vector R represents the direction of outgoing laser light. Vector I and vector R are obtained according to the position of laser 3, reflecting unit 1 and the position of scanning point.

[0045] Furthermore, the S200 also includes: the irradiation normal vector of each reflection unit 1 in the galvanometer is designed to meet requirement R1: a laser irradiation position 5 is set, which represents the position where the laser 4 irradiates the galvanometer. The galvanometer can rotate and move up and down relative to the laser 3 so that each reflection unit 1 on the galvanometer reaches the laser irradiation position 2, and the normal vector of the reflection unit 1 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 in all the reflection units 1 on the galvanometer, so that when the galvanometer is irradiated by the laser 3 in the working state, the reflected scanning points are arranged in an array.

[0046] Furthermore, in the requirement R1, every time the galvanometer rotates 360° / m, the next reflection unit 1 reaches the laser irradiation position.

[0047] Among them, the galvanometer first remains relatively stationary with the laser 3 in the vertical direction. Every time the galvanometer rotates 360° / m, the next reflection unit 1 reaches the laser irradiation position. At this time, the reflection units 1 that reach the laser irradiation position are all in the same reflection unit group. When the galvanometer rotates one circle, all the reflection units 1 in the reflection unit group are irradiated by the laser 3. The galvanometer rotates 360° / m while moving up or down h relative to the laser 3, so that the laser 3 is irradiated on the reflection unit 1 of the next reflection unit group. Then the galvanometer continues to remain stationary in the vertical direction relative to the laser 3, and the galvanometer continues to rotate 360° so that all the reflection units 1 on the reflection unit group are irradiated by the laser 3, and so on until all the reflection units 1 on the galvanometer are irradiated. When the direction of the irradiation normal vector of the reflection unit 1 is different, the laser reflection direction is also different, so that the position of the scanning point is also different, thereby achieving the deflection effect of the galvanometer.

[0048] As an optimization: in the requirement R1, the directions of the illumination normal vectors of all the reflection units 1 on the galvanometer are different.

[0049] It can be understood that such an arrangement enables all the reflective units 1 in a reflective unit group to correspond to one scanning point, resulting in a better scanning effect.

[0050] like Figure 3 As shown, the galvanometer designed by the present invention is distributed with reflection units 1 arranged according to a certain pattern, the galvanometer rotates at a constant speed, and the laser 3 also emits laser at a certain frequency. At the same time, the laser 3 and the galvanometer move regularly and intermittently relative to each other up and down. The galvanometer can move up and down and the laser 3 can be stationary, or the laser 3 can move up and down and the galvanometer can remain stationary in the up and down directions. The relative movement of the two is coordinated with the rotation of this embodiment. When the laser 3 emits laser light, it can be projected onto the corresponding reflection unit 1. After the laser 3 irradiates a reflection unit group, the galvanometer moves one grid up or down relative to the laser 3, that is, moves h, so that the laser 3 irradiates the next reflection unit group. In this way, all the reflection units 1 on the galvanometer can be irradiated by the laser 3, and each reflection unit 1 can reflect a scanning point. All the reflection units 1 of the galvanometer correspond to a scanning matrix.

[0051] Since the galvanometer designed in the present invention can design each reflection unit 1 individually, the direction of the scanning point reflected by the reflection unit 1 can also be designed individually accordingly. Through design, these scanning points are arranged at equal intervals when projected onto the same plane to avoid deformation.

[0052] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above 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 method for designing a non-continuous cylindrical laser radar galvanometer for an autonomous vehicle, characterized in that: include: S100 The basic structure of the galvanometer is designed to be cylindrical. The cylindrical surface is composed of a plurality of reflective unit groups arranged sequentially from top to bottom. Each reflective unit group includes m reflective units evenly distributed around the cylindrical mirror ring, where m is a natural number greater than 1. The S200 calculates the normal direction of the reflective surface of the reflective unit by calculating the position of the laser and the corresponding scanning angle. Each reflective unit is calculated in this way. The specific calculation method for each reflective unit is as follows: The illumination normal vector N of the reflection unit 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） Wherein, vector I represents the incident laser direction, and vector R represents the outgoing laser direction. Vectors I and R are obtained according to the position of the laser, the reflector unit, and the scanning point. The irradiation normal vector design of each reflective unit in the galvanometer meets requirement R1: set a laser irradiation position, set the normal vector of the reflective unit when it is at the laser irradiation position as the irradiation normal vector, and all reflective units on the galvanometer have at least four irradiation normal vectors with different directions, so that when the galvanometer is irradiated by the laser in the working state, the reflected scanning points are arranged in an array.

2. The method for designing a non-continuous cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 1, characterized in that: The design method further includes S300, which includes: designing the rotation angular velocity of the galvanometer and the emission frequency of the laser according to formula (2), （2） Where f is the laser emission frequency and w is the angular velocity of the galvanometer.

3. The method for designing a non-continuous cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 1, characterized in that: In the requirement R1, the directions of the illumination normal vectors of all the reflection units on the galvanometer are different.

4. The method for designing a non-continuous cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 1, characterized in that: In the requirement R1, every time the galvanometer mirror rotates 360° / m, the next reflective unit reaches the laser irradiation position.

5. A method for designing a non-continuous cylindrical laser radar galvanometer for an autonomous driving vehicle according to any one of claims 1 to 4, characterized in that: In the above S100, the basic structural design of the galvanometer must meet requirement R2: a plurality of reflective unit groups are arranged at equal intervals vertically.

6. The method for designing a non-continuous cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 5, characterized in that: In the requirement R2, all reflection units in the galvanometer have the same height.

7. The method for designing a non-continuous cylindrical laser radar galvanometer for an autonomous driving vehicle according to claim 5, characterized in that: In the requirement R2, all the reflection units in the galvanometer are closely arranged.

8. A method for designing a non-continuous cylindrical laser radar galvanometer for an autonomous driving vehicle according to any one of claims 1 to 4, characterized in that: The S100 further includes: designing a support body, and arranging a plurality of reflective unit groups on a surface of the support body.

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