Optical scanning device of compact wind measurement laser radar

Abstract

The invention discloses an optical scanning device of a compact wind measurement laser radar, which is characterized in that a first gear and a second gear are rotatably mounted on a rack, a first optical wedge is mounted in the first gear, a second optical wedge is mounted in the second gear, and wedge angles of the first optical wedge and the second optical wedge are equal; the driving motor is connected with the transmission shaft, a first transmission gear and a second transmission gear are sequentially arranged on the transmission shaft, the first transmission gear is meshed with the first gear, and the second transmission gear is meshed with the second gear; under the driving of the driving motor, the first optical wedge and the second optical wedge perform differential rotation in the same direction or in the reverse direction. A lens cone is installed on the machine frame, a lens and a reflector are installed in the lens cone, and emitted light of the laser radar sequentially passes through the reflector, the lens, the second optical wedge and the first optical wedge to be emitted out. Accurate wind speed detection in the east, south, west, north and zenith directions is achieved, the size needed by the optical lens cone is greatly reduced structurally, and a driving motor is omitted.

Description

Technical Field

[0001] The invention relates to the technical field of wind measuring laser radar, and in particular to an optical scanning device of a compact wind measuring laser radar. Background Art

[0002] For wind measuring lidar, a single beam can only obtain the radial projection of the horizontal wind speed. To obtain the horizontal wind speed vector, a certain scanning mode needs to be adopted, such as multi-beam scanning to obtain the horizontal wind speed projections in multiple radial directions, and then use the corresponding algorithm to invert and solve the horizontal wind speed.

[0003] Common scanning modes include: DBS, PPI, VAD, RHI, glide slope, etc. For wind profile wind laser radar, DBS5 beam (east, south, west, north, zenith) or DBS4 (east, south, west, north) beam scanning mode is mainly used. In most atmospheric environments, the wind direction is not completely horizontal or uniform. Using DBS5 beam measurement can obtain more accurate horizontal and vertical wind field information in this case, while DBS4 beam measurement is more suitable for ideal horizontal wind environment.

[0004] Common scanning mechanisms include: double reflection and optical wedge. The double reflection uses two sets of motors and reflectors to achieve full solid angle scanning. The disadvantage is that two reflections will reduce optical efficiency and require two sets of motors, so the cost is higher and the control is more complicated. The single optical wedge has a simpler structure and only requires one motor drive. The disadvantage is that it can only scan at a specific zenith angle and cannot directly detect the zenith direction to obtain vertical wind speed.

[0005] On the other hand, new demands have also put forward new requirements for scanning modes. For example, for handheld wind measurement lidar, it is concerned with the wind speed in the horizontal direction, and realizes horizontal plane scanning and inversion of the horizontal wind speed of the horizontal plane. However, when using the DBS scanning mode, it is easy for one direction to point to the ground.

[0006] The existing wind-measuring lidars are relatively large in size and are poorly adapted to some special application scenarios, such as offshore buoy wind-measuring lidars. This radar is limited by the size of the platform, as well as the requirements for individual-carrying and handheld scenarios, which also require the product to have a smaller overall size. In order to meet the requirements of radial wind measurement distance, the optical system of the wind-measuring lidar itself has certain aperture and focal length requirements for the transceiver telescope, while existing products mostly use a single-lens structure to transmit the light beam and receive the light signal. The distance from the lens to the focus is approximately equal to the focal length, which results in a larger size of the transceiver telescope, which is not conducive to miniaturization design. For example, a wind-measuring lidar with a detection distance of 2km uses a single-pulse laser energy of 100μJ, so its transceiver telescope needs to have a focal length of more than 300mm.

[0007] Therefore, there is an urgent need for an optical scanning device for a compact wind measurement lidar that can solve one or more of the above problems. Summary of the invention

[0008] In order to solve one or more problems existing in the prior art, the present invention provides an optical scanning device of a compact wind laser radar. The technical solution adopted by the present invention to solve the above problems is: an optical scanning device of a compact wind laser radar, the device is provided with a frame, and comprises: the frame is rotatably mounted with a first gear and a second gear, the first gear is mounted with a first optical wedge, the second gear is mounted with a second optical wedge, and the wedge angles of the first optical wedge and the second optical wedge are equal;

[0009] A driving motor, wherein the driving motor is connected to a transmission shaft, and a first transmission gear and a second transmission gear are sequentially arranged on the transmission shaft, wherein the first transmission gear meshes with the first gear, and the second transmission gear meshes with the second gear;

[0010] Under the drive of the driving motor, the first optical wedge and the second optical wedge rotate at the same speed or at opposite speeds;

[0011] The frame is equipped with a lens barrel, and a lens and a reflector are installed in the lens barrel. The emitted light of the laser radar is emitted through the reflector, the lens, the second optical wedge and the first optical wedge in sequence.

[0012] In some embodiments, the first gear is arranged in parallel with the second gear, and the first optical wedge is arranged in parallel with the second optical wedge.

[0013] In some embodiments, the first optical wedge and the second optical wedge are quartz glass wedges, and a wedge angle of the first optical wedge and the second optical wedge is 15 degrees.

[0014] In some embodiments, a gear ratio between the first gear and the second gear is 20:19, and a gear ratio between the first transmission gear and the second transmission gear is 1:1.

[0015] In some embodiments, a first bearing is disposed between the frame and the first gear, and a third bearing is disposed between the frame and the second gear.

[0016] In some embodiments, a second bearing is disposed between the first gear and the second gear.

[0017] In some embodiments, the lens includes: a first lens and a second lens, the first lens is close to the second optical wedge, and the second lens is close to the reflector.

[0018] In some embodiments, the speed ratio of the first gear and the second gear is set to 19:20, and the first optical wedge and the second optical wedge rotate in the same direction at a differential speed; in an initial state, the inclined surfaces of the first optical wedge and the second optical wedge are parallel, and the first optical wedge rotates 3600 degrees when performing DBS5 beam scanning.

[0019] The technical effect achieved by the present invention is: the double optical wedge structure is used to directly detect the zenith direction, so as to achieve the purpose of performing direct scanning in the east, south, west, north and zenith directions, and to realize accurate wind speed detection in the east, south, west, north and zenith directions. At the same time, the required size of the optical lens barrel is greatly reduced in structure; furthermore, by changing the rotation directions of the two optical wedges to be opposite, an approximate plane scanning mode that cannot be achieved by a single optical wedge can be realized. Compared with a double-mirror scanning device, the device of the present application only needs one driving motor, and is also simpler in structure and control logic. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a cross-sectional view of an optical scanning device of the present invention;

[0021] Figure 2 It is a schematic diagram of the same direction structure of the optical scanning device of the present invention;

[0022] Figure 3 It is a schematic diagram of the reverse structure of the optical scanning device of the present invention;

[0023] Figure 4 This is a schematic diagram of DBS5 beam scanning;

[0024] Figure 5 It is a schematic diagram of elevation plane scanning;

[0025] Figure 6 It is a schematic diagram of handheld plane scanning;

[0026] Figure 7 The scanning trajectory simulation diagram in Example 1

[0027] Figure 8 This is a simulation diagram of the X-coordinate change in Example 1;

[0028] Fig. 9 This is a simulation diagram of the Y coordinate change in Example 1;

[0029] Fig.10 The scanning trajectory simulation diagram in Example 2

[0030] Fig.11 This is a simulation diagram of the reverse change of the X coordinate in Example 2;

[0031] Fig.12 This is a simulation diagram of the Y coordinate change in Example 2;

[0032] Fig.13 This is a simulation diagram of the positive change of the X coordinate in Example 2.

[0033] [Reference Signs]

[0034] 1. frame 10, first bearing 11, second bearing 12, third bearing 2, first gear 3, second gear 4, first optical wedge 5, second optical wedge 6, lens barrel 60, first lens 61, second lens 62, reflector 7, drive motor 70, coupling 71, transmission shaft 8, first transmission gear 9, second transmission gear. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more understandable, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from this description, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0036] The present invention discloses an optical scanning device of a compact wind laser radar, Figure 1 As shown, the device is provided with a frame 1, and a first gear 2 and a second gear 3 are rotatably mounted on the frame 1, a first optical wedge 4 is mounted in the first gear 2, and a second optical wedge 5 is mounted in the second gear 3, and the wedge angles of the first optical wedge 4 and the second optical wedge 5 are equal;

[0037] A driving motor 7, wherein the driving motor 7 is connected to a transmission shaft 71, and a first transmission gear 8 and a second transmission gear 9 are sequentially arranged on the transmission shaft 71, wherein the first transmission gear 8 meshes with the first gear 2, and the second transmission gear 9 meshes with the second gear 3;

[0038] Under the drive of the driving motor 7, the first optical wedge 4 and the second optical wedge 5 rotate at the same speed or at opposite speeds.

[0039] The frame 1 is installed with a lens barrel 6, and a lens and a reflector 62 are installed in the lens barrel 6. The emission light of the laser radar is emitted through the reflector 62, the lens, the second optical wedge 5 and the first optical wedge 4 in sequence.

[0040] It should be pointed out that, combined with Figure 1As shown, the inclined surfaces of the first optical wedge 4 and the second optical wedge 5 are arranged opposite to each other. Furthermore, the inclined surfaces of the first optical wedge 4 and the second optical wedge 5 can also be arranged downward in the same direction (toward the lens barrel 60). The two inclined surface settings affect the initial angles of the two optical wedges in the initial state, but do not affect the final technical effect. The first gear 2 is arranged in parallel with the second gear 3, and the first optical wedge 4 and the second optical wedge 5 are arranged in parallel. The first optical wedge 4 and the second optical wedge 5 are quartz glass wedges, and the wedge angle of the first optical wedge 4 and the second optical wedge 5 is 15 degrees. As shown Figure 4 As shown, when the present application performs DBS5 beam scanning, it will scan the east, south, west, north and zenith directions, wherein the zenith is the Z-axis direction, the scanning light beam circles around the Z-axis and forms a scanning range, and the angle (zenith angle) between the scanning light beam and the Z-axis is related to the wedge light of the first light wedge and the second light wedge, and when the wedge angle is 15 degrees, the zenith angle is 30 degrees.

[0041] Specifically, the gear ratio of the first gear 2 to the second gear 3 is 20:19. Figure 1 The number of teeth of the first gear 2 is 100, the number of teeth of the second gear 3 is 95, the first transmission gear 8 and the second transmission gear 9 are bevel gears, and their gear ratio is 1:1. Figure 1 The number of teeth of the two gears is 18. By exchanging the meshing position of the second gear 3 and the second transmission gear 9, the first optical wedge 4 and the second optical wedge 5 can be rotated in the same direction or in the opposite direction.

[0042] Specifically, the same direction structure is: when the first optical wedge 4 and the second optical wedge 5 rotate in the same direction at a differential speed, the structure of the device of the present application is as follows: Figure 2 As shown, the inclined surfaces of the first optical wedge 4 and the second optical wedge 5 are both facing the direction of the lens barrel 6, the second gear 3 is meshed on the upper side of the second transmission gear 9, and the driving motor 7 is connected to the transmission shaft 71 through a coupling 70;

[0043] Reverse structure: When the first optical wedge 4 and the second optical wedge 5 rotate at opposite speeds, the structure of the device of the present application is as follows: Figure 3 As shown, the second gear 3 is meshed with the lower side of the second transmission gear 9, and the remaining structure is basically the same as the above-mentioned same-direction structure.

[0044] Again, combined Figure 2 , Figure 3 As shown, in order to improve the smoothness of the scanning device during operation, a first bearing 10 is arranged between the frame 1 and the first gear 2, a third bearing 12 is arranged between the frame 1 and the second gear 3, and a second bearing 11 is arranged between the first gear 2 and the second gear 3.

[0045] Specifically, combined Figure 1-Figure 3 As shown, the lens includes: a first lens 60 and a second lens 61 , the first lens 60 is close to the second optical wedge 5 , and the second lens 61 is close to the reflector 62 .

[0046] Embodiment 1, combination Figure 2 As shown, in the above-mentioned co-directional structure, the emitted light is collimated and passes through the reflector 62 to enter the second lens 61, the first lens 60, the second optical wedge 5 and the first optical wedge 4 in sequence, and the parameters are set: the wedge angle of the two optical wedges is 15 degrees, the speed ratio of the first gear 2 and the second gear 3 is 19:20, the actual number of teeth of the first gear 2 and the second gear 3 are 100 and 95 respectively, the first optical wedge 4 and the second optical wedge 5 rotate in the same direction at a differential speed, and in the initial state, the inclined surfaces of the first optical wedge 4 and the second optical wedge 5 are parallel;

[0047] During operation, the first and second optical wedges rotate driven by the first and second gears. Due to the different rotation speeds, the rotation angles of the first optical wedge 4 and the second optical wedge 5 will be different. The direction of the normal line of the optical wedge slope rotates with the rotation of the optical wedge, and the direction of the refracted light beam will also rotate with the rotation of the optical wedge.

[0048] For VAD scanning or DBS4 scanning, when the first optical wedge 4 rotates 360 degrees, a 360-degree VAD scanning or DBS4 scanning with a zenith angle of 30 degrees can be realized. When the first optical wedge 4 rotates 3600 degrees, the rotation angles of the first optical wedge 4 and the second optical wedge 5 differ by 180 degrees. At this time, scanning in the zenith direction is realized, that is, DBS5 scanning with a zenith angle of 30 degrees is realized. For DBS5 scanning, please refer to Figure 4 The specific scanning trajectory is shown in Figure 7 As shown, from Figure 7 It can be seen that there are approximately circular ring-shaped tracks and dot-shaped tracks located at the center end; the line graph of the change of the X coordinate of the scanning point corresponding to the light beam and the rotation angle of the first optical wedge 4 is as follows: Figure 8 As shown, the line graph of the change of the Y coordinate of the scanning point corresponding to the light beam and the rotation angle of the first optical wedge 4 is as follows: Fig. 9 As shown, combined Figure 7-Figure 9 At the beginning, the coordinates of the scanning point are (30, 0), and the scanning is performed counterclockwise. When the first optical wedge 4 rotates 360 degrees, the device completes the scanning of the east, south, west, and north. At this time, the X-axis coordinate of the scanning point is 30, and the Y-axis coordinate is close to 0. As the first optical wedge 4 continues to rotate and approaches the rotation angle of 3600 degrees, the Y-axis coordinate of the scanning point will eventually approach 0. When the rotation of the first optical wedge 4 is close to 3600 degrees, the X-axis coordinate of the scanning point will eventually be equal to 0, thereby realizing the scanning of the zenith direction.

[0049] When performing a plane scan, the device scans as follows Figure 5 , Figure 6 As shown, at this time, based on Example 1, the first optical wedge 4 is first rotated by 4 degrees alone, so that in the subsequent synchronous drive, the second optical wedge 5 lags behind the first optical wedge by 4 degrees in advance, and then the first optical wedge 4 and the second optical wedge 5 are synchronously driven to rotate by the drive motor 7. After the first optical wedge 4 is rotated 180 degrees, a plane scanning range with an angle of approximately 60 degrees can be obtained (nearly 30 degrees on one side and 60 degrees on both sides).

[0050] Embodiment 2, combined Figure 3 As shown, in the above reverse structure, the emitted light is collimated and passes through the reflector 62 to enter the second lens 61, the first lens 60, the second optical wedge 5 and the first optical wedge 4 in sequence, and the parameters are set as follows: the wedge angle of the two optical wedges is 15 degrees, the speed ratio of the first gear 2 and the second gear 3 is 19:20, the actual number of teeth of the first gear 2 and the second gear 3 are 100 and 95 respectively, and the first optical wedge 4 and the second optical wedge 5 rotate in opposite directions at differential speeds;

[0051] Assume that the first optical wedge 4 rotates clockwise and the second optical wedge 5 rotates counterclockwise, and the state in which the inclined surfaces of the first optical wedge 4 and the second optical wedge 5 are parallel is taken as the reference state. Under this reference state, the second optical wedge 5 is rotated 4 degrees in the opposite direction in advance (that is, the second optical wedge 5 is rotated 4 degrees clockwise in advance), and the state after completing the rotation of 4 degrees is taken as the initial state.

[0052] For approximate plane scanning, when the first optical wedge 4 rotates 180 degrees, a plane scanning range with an angle of approximately 30 degrees is completed. The specific scanning trajectory is as follows: Fig.10 As shown in FIG. 1 , it can be seen that an approximate plane scanning range of 30 can be obtained. The line graph of the change of the X coordinate of the scanning point corresponding to the light beam and the rotation angle of the first optical wedge 4 is shown in FIG. Fig.11 , Fig.13 As shown, the line graph of the change of the Y coordinate of the scanning point corresponding to the light beam and the rotation angle of the first optical wedge 4 is as follows: Fig.12 As shown, in order to facilitate the comparison between forward rotation and reverse rotation, Fig.11 The first optical wedge 4 rotates in the positive direction. Fig.12 The first optical wedge 4 rotates in the opposite direction. Fig.13 The first optical wedge 4 rotates in the opposite direction;

[0053] Combination Fig.10 , Fig.12 , Fig.13As shown, the scanning angle of the scanning point changes from horizontal -30 degrees to 30 degrees, with a total range of 60 degrees, and the pitch angle changes by about 2 degrees, thereby achieving approximate plane scanning, satisfying handheld plane scanning and elevation plane scanning at a certain angle.

[0054] In summary, the dual optical wedge structure can be used to directly detect the zenith direction, so as to achieve the purpose of performing direct scanning in the east, south, west, north and zenith directions, and realize accurate wind speed detection in the east, south, west, north and zenith directions. At the same time, the required size of the optical lens barrel is greatly reduced in structure. Furthermore, by changing the rotation directions of the two optical wedges to be opposite, an approximate plane scanning mode that cannot be achieved by a single optical wedge can be achieved. Compared with a dual-mirror scanning device, the device of the present application only requires one drive motor, and is also simpler in structure and control logic.

[0055] The above-described embodiments only express one or more implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. An optical scanning device for a compact wind laser radar, the device being provided with a frame, characterized in that: The frame is rotatably mounted with a first gear and a second gear, the first gear is equipped with a first optical wedge, the second gear is equipped with a second optical wedge, and the wedge angles of the first optical wedge and the second optical wedge are equal; A driving motor, wherein the driving motor is connected to a transmission shaft, and a first transmission gear and a second transmission gear are sequentially arranged on the transmission shaft, wherein the first transmission gear meshes with the first gear, and the second transmission gear meshes with the second gear; Under the drive of the driving motor, the first optical wedge and the second optical wedge rotate at the same speed or at opposite speeds; The frame is equipped with a lens barrel, in which a lens and a reflector are installed. The emitted light of the laser radar is emitted through the reflector, the lens, the second optical wedge and the first optical wedge in sequence.

2. The optical scanning device of the compact wind laser radar according to claim 1, characterized in that: The first gear is arranged in parallel with the second gear, and the first optical wedge is arranged in parallel with the second optical wedge.

3. The optical scanning device of the compact wind laser radar according to claim 1 or 2, characterized in that: The first optical wedge and the second optical wedge are quartz glass wedges, and the wedge angles of the first optical wedge and the second optical wedge are 15 degrees.

4. The optical scanning device of the compact wind laser radar according to claim 3, characterized in that: The gear ratio of the first gear and the second gear is 20:19, and the gear ratio of the first transmission gear and the second transmission gear is 1:

1.

5. The optical scanning device of the compact wind laser radar according to claim 1, characterized in that: A first bearing is arranged between the frame and the first gear, and a third bearing is arranged between the frame and the second gear.

6. The optical scanning device of the compact wind laser radar according to claim 1 or 5, characterized in that: A second bearing is disposed between the first gear and the second gear.

7. The optical scanning device of the compact wind laser radar according to claim 1, characterized in that: The lens comprises: a first lens and a second lens, wherein the first lens is close to the second optical wedge, and the second lens is close to the reflector.

8. The optical scanning device of the compact wind laser radar according to claim 1, characterized in that: The speed ratio of the first gear and the second gear is set to 19:20, and the first optical wedge and the second optical wedge rotate in the same direction with differential speed; in the initial state, the inclined surfaces of the first optical wedge and the second optical wedge are parallel, and the first optical wedge rotates 3600 degrees when performing DBS5 beam scanning.

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