Laser radar scanning device

Abstract

The invention relates to a laser radar scanning device. The device comprises a rotating shaft; the inner cam body and the outer cam body are nested and fixed on the rotating shaft and rotate along with the rotating shaft; a reflection cavity is formed between the inner cam body and the outer cam body. The inner reflective mirror is arranged on the inner cam body and synchronously rotates along with the inner cam body; the outer reflective mirror is arranged in the outer cam body and synchronously rotates along with the outer cam body; wherein the inner reflective mirror and the outer reflective mirror are correspondingly arranged and form a reflective mirror group; after the laser beam enters the reflection cavity, the laser beam is emitted to the surface of the object to be measured through the rotating reflective mirror set to form laser return light, and after the laser return light enters the reflection cavity, the laser return light is emitted through the rotating reflective mirror set, so that a scanning result of the object to be measured is obtained based on the laser return light. The problem that a traditional laser radar scanning device cannot give consideration to ambient light interference suppression and wide-view-field scanning is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser radar scanning technology, in particular to a laser radar scanning device. BACKGROUND

[0002] The laser radar scanning device generally refers to the laser beam emitted and the laser return light reflected by the object received. Among them, the angle coverage range of scanning and the anti-environmental light interference ability directly determine the reliability and accuracy of detection. Therefore, it is important to realize large range and high signal-to-noise ratio scanning in complex lighting environment.

[0003] The traditional laser radar scanning device only has an open or semi-open optical path, which is easy to be disturbed by environmental stray light, resulting in a decrease in signal-to-noise ratio during scanning, and still relies on a simple structure of single-point rotation or swing mirror, and the scanning angle range is usually strictly limited by the mechanical structure. SUMMARY

[0004] Based on the foregoing analysis, the present application provides a laser radar scanning device, the main purpose is to solve the problem that the traditional laser radar scanning device cannot balance the environmental light interference suppression and wide field scanning.

[0005] To this end, the laser radar scanning device of the present application comprises: a rotating shaft; an inner cam body and an outer cam body, which are nested and fixed on the rotating shaft and rotate with the rotating shaft; wherein the inner cam body and the outer cam body form a reflection cavity; an inner mirror is arranged on the inner cam body and rotates synchronously with the inner cam body; an outer mirror is arranged in the outer cam body and rotates synchronously with the outer cam body; wherein the inner mirror and the outer mirror are correspondingly arranged and form a mirror group; after the laser beam enters the reflection cavity, it is emitted to the surface of the object to be measured through the rotating mirror group, forms a laser return light and is emitted after entering the reflection cavity, and the scanning result of the object to be measured is obtained based on the laser return light.

[0006] As a preferred, it further comprises: at least two inner mirrors and at least two outer mirrors are arranged; the inner mirror is arranged at one or more positions of the side and top of the inner cam body; the outer mirror is arranged at one or more positions of the inner side and inner top of the outer cam body.

[0007] As a further preferred, it further comprises: the normal direction of each inner mirror and the rotating shaft form an acute angle deflection angle, and the normal direction of each outer mirror corresponding to the inner mirror and the rotating shaft form an acute angle shaft deflection angle; and the angle difference between the acute angle deflection angle of each inner mirror and the acute angle shaft deflection angle of any outer mirror forming a light path with the inner mirror is within the range.​

[0008] As a further preferred, it further comprises that the angle of the acute deflection angle is in the range of and the angle of the acute axial deflection angle is in the range of .

[0009] As a further preferred, the inner reflector is distributed along the circumference of the inner cam body, and the angle of the corresponding acute deflection angle is linearly increased.

[0010] As a preferred, it further comprises that the inner reflector and the inner cam body, the outer reflector and the outer cam body are integrally formed; or the inner reflector and the inner cam body, the outer reflector and the outer cam body are fixed through an adjusting support.

[0011] As a preferred, the inner cam body and the outer cam body are integrally formed, and the inner cam body and the outer cam body rotate synchronously and in the same direction with consistent angular velocity.

[0012] As a preferred, the inner cam body and the outer cam body are separately arranged; the inner cam body and the outer cam body rotate synchronously and in the same direction with consistent angular velocity; or the inner cam body is fixed on the rotating shaft through a transmission mechanism, so that the inner cam body and the outer cam body rotate synchronously and in opposite directions with consistent angular velocity.

[0013] As a preferred, the outer cam body is a hollow surface or a transparent surface towards the direction of the laser beam incidence, so that the laser beam or the laser return light is incident or emitted into or out of the reflection cavity.

[0014] As a preferred, it further comprises a laser emitter and a laser detector; the laser emitter is used for emitting the laser beam; and the laser detector is used for receiving the laser return light.

[0015] The laser radar scanning device has the following beneficial effects: Firstly, unlike the traditional open or semi-open design which is easily disturbed by stray light, the reflection cavity formed by the nested inner cam body and outer cam body accommodates the incident laser beam or laser return light, so as to isolate the reflected light path from the external stray light, thereby realizing the interference suppression of ambient light.

[0016] Secondly, unlike the traditional single-point rotating mirror which is limited by the scanning angle of the mechanical structure, the inner cam body and the outer cam body are synchronously rotated with the rotating shaft to synchronously drive the reflector group, so as to dynamically expand the deflection degree of freedom of the laser path, thereby significantly widening the scanning field of view.

[0017] ​​Again, unlike the traditional swing lens which cannot maintain the stability of the light path in rotation, the present scheme forms a precise reflected light path continuously or discretely in the dynamic scanning process through the corresponding setting and synchronous rotation of the inner and outer mirrors, thereby improving the accuracy of the scanning results of the object to be measured. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the structure and light path schematic diagram of the laser radar scanning device of an embodiment of the present application; Reference signs: 1-1. Inner cam body, 1-2. Outer cam body, 1-3. Rotation shaft, 2-1. Inner mirror, 2-2. Outer mirror, 3. Object to be measured. DETAILED DESCRIPTION

[0019] The present application will be described in more detail below with reference to the accompanying drawings. It should be noted that the following description of the present application with reference to the accompanying drawings is merely illustrative and not restrictive.

[0020] In the case possible, each different embodiment described below can be recombined with each other to constitute other embodiments not shown in the following description; each different technical feature described below can also be recombined with each other to constitute other embodiments not shown in the following description.

[0021] Embodiment 1: To solve the problem that the traditional laser radar scanning device cannot balance the environmental light interference suppression and wide field scanning, please refer to the accompanying drawings Figure 1 The present embodiment provides a laser radar scanning device, which mainly comprises the following structures: a rotation shaft 1-3, an inner cam body 1-1 and an outer cam body 1-2 which are fixedly embedded on the rotation shaft and rotate with the rotation shaft, wherein the inner cam body and the outer cam body form a reflection cavity for accommodating the incident laser beam or laser return light. It also includes an inner mirror 2-1 arranged on the inner cam body and rotating synchronously with the inner cam body, and an outer mirror 2-2 arranged in the outer cam body and rotating synchronously with the outer cam body. Among them, the inner mirror and the outer mirror are correspondingly arranged and form a mirror group, which can reflect the laser beam or laser return light entering the reflection cavity in a programmable light path. When the device is running, after the laser beam enters the reflection cavity, it is emitted to the surface of the object to be measured 3 through the rotating mirror group, and after the laser return light is formed and enters the reflection cavity, it is emitted through the rotating mirror group. Based on the emission angle, total elapsed time and other data carried by the laser return light, the scanning result of the object to be measured is obtained.

[0022] The closed reflection cavity constructed by the nested inner and outer cam bodies physically isolates the ambient stray light interference, significantly improving the signal-to-noise ratio under complex illumination. At the same time, the inner and outer cam bodies synchronously drive the rotating mirror group to rotate with the rotating shaft, and the multi-angle dynamic deflection characteristics break through the traditional single-mirror mechanical constraints, realizing the wide-field scanning coverage in horizontal and vertical directions. The spatial corresponding arrangement and synchronous rotation of the rotating mirror group ensure the stability of the optical path alignment in high-speed motion, and the focusing effect of the reflection cavity on the light path combined with the programmable reflecting mirror group optimizes the receiving efficiency and scanning accuracy of the laser light. The dual requirements of ambient light suppression and large-range high-precision scanning can be simultaneously solved in a short rotation period.

[0023] In order to improve the flexibility and optical path controllability of the laser radar scanning device in wide-field scanning, in some other embodiments, one inner mirror and multiple outer mirrors distributed along the inner circumference of the outer cam body, or one outer mirror and multiple inner mirrors distributed along the side of the inner cam body can be provided, and the inner and outer mirrors rotate synchronously with the corresponding cam bodies. After the laser beam or the light enters the reflection cavity, it is selectively reflected by the first mirror and then outputted by the other mirrors according to the incident angle and the rotation state. This scheme enhances the diversity of the light path through the multi-point distributed outer mirrors, or improves the programmability of the emission path through the multiple inner mirrors, thereby realizing more flexible field coverage and higher scanning resolution without increasing the system complexity, while maintaining the compactness and stability of the optical path, improving the detection accuracy and signal-to-noise ratio in complex environments.

[0024] In order to eliminate the scanning blind area in the rotating axis direction and expand the vertical field of view, in a preferred embodiment, at least two inner mirrors and at least two outer mirrors are provided, wherein the inner mirrors are arranged at one or more positions on the side and top of the inner cam body, and the outer mirrors are arranged at one or more positions on the inner side and inner top of the outer cam body. This embodiment expands the vertical scanning angle to more than 90° without mechanical dead zone through the spatial cooperation of the top and side mirror groups, significantly improves the vertical resolution, and increases the number of inner mirrors and outer mirrors as reflection nodes, thereby increasing the number of effective laser projections per unit time and increasing the point cloud density formed by the final laser light, to improve the accuracy of the scanned object scanning results.

[0025] In order to optimize the optical coupling efficiency in the reflection cavity and suppress the influence of stray light reflection on the internal optical path, in a further preferred embodiment, the normal direction of each inner mirror forms an acute angle with the rotating shaft, and the normal direction of each outer mirror corresponding to the inner mirror forms an acute angle with the rotating shaft. The angle difference between the acute angle of each inner mirror and the acute angle of any outer mirror forming an optical path is less than 10°. ~ Within the range. In this embodiment, the acute angle deflection angle of each internal mirror. acute axial deflection angle with any external mirror forming an optical path When the angles are equal, that is, when the angle difference is taken as... At this time, the energy utilization rate is highest when the laser beam is incident or reflected by the two mirrors, while when... At this time, the scanning angle of the device is at its maximum. In another embodiment, , At this time, the two form Deflection, which is suitable for high-density local scanning. In another embodiment, At this point, the difference between the two is taken as It has the highest energy utilization rate and can achieve The increased field-of-view subheight can significantly improve the uniformity of the point cloud formed by laser backlighting. In another embodiment, the angle difference controls the angle between the incident and reflected light. ,when When the critical condition for total internal reflection is met, energy loss can be effectively avoided.

[0026] To balance scanning range and mechanical reliability, in a further preferred embodiment, the acute angle deflection angle... Angle at ~ Within the range, and the acute angle axis deflection angle Angle at ~ Within the specified range. In this embodiment, the design significantly improves the performance and reliability of the lidar scanning device by precisely controlling the acute deflection angle of the inner mirror and the acute axis deflection angle of the outer mirror. Acute deflection angle With acute axis deflection angle The angle difference between the inner and outer mirrors jointly determines the net deflection direction of the laser beam. A smaller angle difference results in higher beam reflection efficiency, thus improving scanning accuracy. Furthermore, the angle difference range must encompass manufacturing tolerances, but should not be too large to avoid performance degradation due to extreme values. Ensuring all angles are positive and reasonable further enhances system stability. The continuous and stable angle difference between the inner and outer mirrors ensures that, under any... There exists a suitable ,make and keep exist Within the optical path range, high-precision, wide-field-of-view laser scanning can be achieved. Among them, , At this time, the angle design of the acute deflection angle and the acute axial deflection angle can minimize the centrifugal stress on the mirror surface and ensure the operational stability of the device at an ultra-high speed of 20,000 rpm. , When the acute deflection angle and the acute deflection angle are designed, the single-mirror deflection capability can be maximized, and the horizontal field of view angle can be increased to 180°. In another embodiment, , When the acute deflection angle and the acute deflection angle are designed, the single-mirror deflection capability can be maximized, and the horizontal field of view angle can be increased to 180°. In another embodiment, , When the acute deflection angle and the acute deflection angle are designed, the single-mirror deflection capability can be maximized, and the horizontal field of view angle can be increased to 180°. In another embodiment,

[0027] In order to achieve equal-angle resolution sampling during rotation scanning, in a further preferred embodiment, the inner mirror is distributed along the circumference of the inner cam body, and the corresponding acute deflection angle is linearly increased, and the acute axis deflection angle related thereto also needs to be correspondingly arranged to ensure the vertical scanning coverage and meet the requirements from the minimum elevation angle to the maximum elevation angle, suitable for typical When the acute deflection angle and the acute deflection angle are designed, the single-mirror deflection capability can be maximized, and the horizontal field of view angle can be increased to 180°. In another embodiment,

[0028] In order to eliminate the micro-displacement of the mirror body during high-speed rotation and improve its optical durability, in another preferred embodiment, the inner mirror and the inner cam body, and the outer mirror and the outer cam body are integrally formed, which can avoid the vibration deviation caused by traditional gluing or screwing, and reduce the optical path alignment difference of the inner and outer mirrors during rotation. In another embodiment, the inner and outer mirrors can be coated with a reflective film, and the wavelength of the reflective film can be set according to actual needs.

[0029] In order to realize real-time online calibration of optical path parameters, in another preferred embodiment, the inner mirror and the inner cam body, and the outer mirror and the outer cam body are fixed through adjusting supports. By adjusting the angle of the adjusting support, the angle of the inner and outer mirrors can be programmed, which is convenient for calibrating the angle of the inner and outer mirrors and adjusting the optical path angle and direction based on actual application scenarios. In another embodiment, the adjusting support can respond to microsecond-level electrical signals and dynamically compensate for mechanical deformation caused by rotation, thereby realizing rapid adjustment of the angle of the inner and outer mirrors.

[0030] ​​In order to minimize the energy loss when the laser beam is incident and maintain the semi-closed nature of the inside of the reflection cavity, in another preferred embodiment, the side of the outer cam body facing the direction of the laser beam incidence can be provided as a hollowed-out surface or a transparent surface, so that the laser beam and the laser return light can smoothly enter and exit the reflection cavity. Among them, the hollowed-out surface can be adjusted according to the internal programmed light path, so as to prevent the bottom stray light from affecting the scanning result on the premise that the incident laser beam and the laser return light can smoothly enter and exit the reflection cavity. At the same time, it can also be provided as a transparent surface alone or in combination with the hollowed-out surface. In another embodiment, a customized optical window with a transmittance of >99.5% can be used to reduce the loss of incident light, to improve the utilization rate of laser and to maintain the isolation ability of the reflection cavity to external light, to ensure the effective detection of weak laser return light signals.

[0031] In order to accurately compensate for the unbalance of the rotating parts, reduce vibration noise and improve rotational speed stability, in another preferred embodiment, a counterweight structure is provided on the rotating shaft to offset the rotational inertia force generated when the optical cam rotates. In some other embodiments, the counterweight structure can be provided above and below the outer cam body, at the connection between the outer cam body and the rotating shaft, at the connection between the inner cam body and the rotating shaft, etc., to achieve the effect of offsetting the inertia force.

[0032] Embodiment 2: In order to eliminate the assembly error between the nested cam bodies and improve the dynamic balance at high speed, on the basis of embodiment 1, in the laser radar scanning device of this embodiment: the inner cam body and the outer cam body are designed as one body, and the inner cam body and the outer cam body rotate synchronously and in the same direction, with consistent angular velocity. The above design can maximize the synchronous rotation of the inner and outer cams, thereby improving the accuracy of the scanning result.

[0033] Embodiment 3: In order to adapt to different scanning mode requirements and reduce manufacturing complexity, on the basis of embodiment 1, in the laser radar scanning device of this embodiment: the inner cam body and the outer cam body are designed as separate bodies, which can make the device configuration more flexible.

[0034] In order to adapt to different scanning mode requirements and reduce manufacturing complexity, in a preferred embodiment, the inner cam body and the outer cam body rotate synchronously and in the same direction, with consistent angular velocity. Among them, the split design allows for customized cam curves, such as sinusoidal trajectory of the inner cam and linear trajectory of the outer cam, which can significantly improve the programmability of the scanning trajectory. At the same time, synchronous rotation can guarantee the dynamic sealing of the inside of the reflection cavity, thereby suppressing the signal-to-noise ratio of stray light.

[0035] In order to break through the field of view limit, in another preferred embodiment, the inner cam body is fixed on the rotating shaft through a transmission mechanism, so that the inner cam body rotates reversely synchronously with the outer cam body, and the angular velocities are consistent. Among them, the reverse rotation doubles the relative running speed of the mirror group, thereby increasing the adaptive light path of the inner and outer mirrors at different angles, forming discrete laser return light while breaking through the original field of view limit, and expanding the maximum acute angle deflection angle of the laser beam to twice that of the traditional same direction mode, i.e. the horizontal field of view reaches 240°. Moreover, by modulating the phase difference of the inner and outer cam bodies, the scanning blind area can be eliminated, thereby significantly improving the scanning coverage and the fineness of the point cloud.

[0036] Embodiment 4: In order to construct a complete signal transmitting and receiving link and be compatible with multi-mode detection requirements, on the basis of Embodiment 2 or 3, the laser radar scanning device of the present embodiment further comprises a laser transmitter and a laser detector. The laser transmitter is mainly used for transmitting a laser beam, and the laser detector is mainly used for receiving laser return light. By explicitly setting the laser transmitter and the detector, the laser loop of the scanning device is completely defined. In some other embodiments, the laser beam can be a single laser beam or multiple laser beams to adapt to different scanning resolution, speed or target characteristics.

[0037] Although the above has shown and described several specific embodiments of the present application, it should be understood that the above-mentioned embodiments are only exemplary and cannot be understood as limiting the scope of protection of the present application, and any non-essential changes and substitutions made by those skilled in the art fall within the scope of protection claimed by the present application.

Claims

1. A lidar scanning device, characterized in that, include: Rotation axis; The inner cam body and the outer cam body are nested and fixed on the rotating shaft, and both rotate with the rotating shaft; wherein, the inner cam body and the outer cam body form a reflective cavity; An inner reflector is mounted on the inner cam body and rotates synchronously with the inner cam body; An external reflector is disposed within the outer cam body and rotates synchronously with the outer cam body; The inner reflector and the outer reflector are respectively arranged to form a reflector group; After the laser beam enters the reflecting cavity, it is emitted to the surface of the object under test through the rotating reflector group, forming a laser backlight that enters the reflecting cavity and is emitted again through the rotating reflector group, so as to obtain the scanning result of the object under test based on the laser backlight.

2. The lidar scanning device according to claim 1, characterized in that, Also includes: At least two of the inner reflectors and at least two of the outer reflectors are provided; The internal reflector is disposed at one or more locations on the side or top of the internal cam body; The external reflector is disposed at one or more locations on the inner side or inner top of the outer cam body.

3. The lidar scanning device according to claim 2, characterized in that, Also includes: The normal direction of each of the inner mirrors forms an acute deflection angle with the rotation axis, and corresponding to the inner mirrors, the normal direction of each of the outer mirrors forms an acute axial deflection angle with the rotation axis. Furthermore, the angular difference between the acute deflection angle of each inner mirror and the acute axial deflection angle of any outer mirror forming an optical path with it is within the range of... ~ Within the range.

4. The lidar scanning device according to claim 3, characterized in that, Also includes: The angle of the acute deflection angle is in ~ Within the range, and the angle of the acute axial deflection is within ~ Within the range.

5. The lidar scanning device according to claim 3 or 4, characterized in that, The inner reflectors are distributed circumferentially along the inner cam body, and the corresponding acute deflection angles increase linearly.

6. The lidar scanning device according to claim 1, characterized in that, Also includes: The inner reflector and the inner cam body, and the outer reflector and the outer cam body are all integrally formed; or The inner reflector and the inner cam body, and the outer reflector and the outer cam body are all fixed by an adjusting bracket.

7. The lidar scanning device according to claim 1, characterized in that, The inner cam body and the outer cam body are integrally formed, and the inner cam body and the outer cam body rotate synchronously in the same direction with the same angular velocity.

8. The lidar scanning device according to claim 1, characterized in that, The inner cam body and the outer cam body are separately configured; The inner cam body and the outer cam body rotate synchronously and in the same direction, with the same angular velocity; or The inner cam body is fixed on the rotating shaft by a transmission mechanism, so that the inner cam body and the outer cam body rotate synchronously in opposite directions and have the same angular velocity.

9. The lidar scanning device according to claim 1, characterized in that, The outer cam body has a hollow or transparent surface facing the laser beam incident direction, so that the laser beam or the laser backlight can enter and exit the reflection cavity.

10. The lidar scanning device according to claim 1, characterized in that, It also includes laser emitters and laser detectors; The laser emitter is used to emit the laser beam; The laser detector is used to receive the laser backlight.

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