Optical scanning device of compact wind measurement laser radar
By using the differential rotation of the double optical wedge structure, a compact optical scanning device for wind-measuring lidar was realized, solving the problems of large size and complex scanning modes. It achieved accurate wind speed detection and near-planar scanning in the zenith direction, while reducing the size of the optical tube and the complexity of control.
Patent Information
- Application Number
- CN202422877456.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-11-25
AI Technical Summary
Existing wind-measuring lidar devices are large in size and difficult to adapt to special application scenarios, such as the needs of marine buoys, individual soldier backpacks, and handheld devices. At the same time, existing scanning modes cannot effectively obtain horizontal wind speed vectors, and the optical system design is complex and costly.
By employing a dual-wedge structure, the first and second optical wedges rotate at different speeds in the same or opposite directions, combined with a single motor drive, to achieve direct detection and near-planar scanning of the zenith direction, simplifying the structure and reducing the size of the optical tube.
It achieves accurate wind speed detection in the east, south, west, north, and zenith directions. Its compact structure reduces the size of the optical tube and simplifies the control logic and cost.
Smart Images
Figure CN223513341U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of wind-measuring lidar technology, and in particular to an optical scanning device for a compact wind-measuring lidar. Background Technology
[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 is required, such as multi-beam scanning to obtain the horizontal wind speed projection in multiple radial directions, and then the corresponding algorithm is used to invert and solve for the horizontal wind speed.
[0003] Common scanning modes include DBS, PPI, VAD, RHI, and glide slope. For wind profiler lidar, the DBS5 (East, South, West, North, Zenith) or DBS4 (East, South, West, North) beam scanning modes are primarily used. In most atmospheric environments, wind direction is neither perfectly horizontal nor perfectly uniform. DBS5 beam measurements can obtain more accurate horizontal and vertical wind field information under these conditions, while DBS4 beam measurements are more suitable for ideal horizontal wind environments.
[0004] Common scanning mechanisms include dual-reflection and optical wedge types. The dual-reflection type uses two sets of motors and mirrors to achieve full-angle scanning. However, the drawbacks are that the two reflections reduce optical efficiency and require two sets of motors, resulting in higher cost and more complex control. The single optical wedge type has a simpler structure, requiring only one motor. However, it can only scan at a specific zenith angle and cannot directly detect vertical wind speed in the zenith direction.
[0005] On the other hand, new demands have also placed new requirements on scanning modes. For example, handheld wind-measuring lidar is concerned with the wind speed in the horizontal direction and needs to achieve horizontal plane scanning and inversion of the horizontal wind speed on that plane. However, it is easy for one direction to point towards the ground when using the DBS scanning mode.
[0006] Existing wind-measuring lidars are relatively large, making them poorly suited for certain specialized applications, such as offshore buoy wind-measuring lidars. These applications are limited by platform size and require individual soldier carrying or handheld operation, necessitating a smaller overall size. To meet radial wind measurement distance requirements, the optical system of wind-measuring lidar has specific aperture and focal length requirements for the transceiver telescopes. However, existing products often use a single-lens structure for both beam transmission and signal reception, with the distance from the lens to the focal point approximately equal to the focal length. This results in a large transceiver telescope size, hindering miniaturization. For example, a wind-measuring lidar with a detection range of 2km using 100μJ single-pulse laser energy would require a transceiver telescope with a focal length exceeding 300mm.
[0007] Therefore, there is an urgent need for a compact optical scanning device for wind-measuring lidar that can solve one or more of the above problems. Utility Model Content
[0008] To address one or more problems existing in the prior art, this utility model provides an optical scanning device for a compact wind-measuring lidar. The technical solution adopted by this utility model to solve the above problems is: an optical scanning device for a compact wind-measuring lidar, the device being provided with a frame, comprising: a first gear and a second gear rotatably mounted on the frame, a first optical wedge installed inside the first gear, and a second optical wedge installed inside the second gear, the wedge angles of the first and second optical wedges being equal;
[0009] A drive motor is connected to a transmission shaft, on which a first transmission gear and a second transmission gear are sequentially arranged. The first transmission gear meshes with the first gear, and the second transmission gear meshes with the second gear.
[0010] Driven by the drive motor, the first optical wedge and the second optical wedge rotate in the same direction at a differential speed or in opposite directions at a differential speed.
[0011] The frame is equipped with a lens barrel, and a lens and a reflector are installed inside the lens barrel. The emitted light of the lidar passes through the reflector, the lens, the second optical wedge, and the first optical wedge in sequence before being emitted.
[0012] In some embodiments, the first gear and the second gear are arranged in parallel, and the first optical wedge and the second optical wedge are arranged in parallel.
[0013] In some embodiments, the first optical wedge and the second optical wedge are quartz glass optical wedges, and the wedge angle of the first optical wedge and the second optical wedge is 15 degrees.
[0014] In some embodiments, the tooth ratio of the first gear to the second gear is 20:19, and the tooth ratio of the first transmission gear to the second transmission gear is 1:1.
[0015] In some embodiments, a first bearing is provided between the frame and the first gear, and a third bearing is provided between the frame and the second gear.
[0016] In some embodiments, a second bearing is provided between the first gear and the second gear.
[0017] In some embodiments, the lens includes 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.
[0018] In some embodiments, the inclined surface of the first optical wedge is disposed opposite to or in the same direction downwards from the inclined surface of the second optical wedge.
[0019] The technical effects achieved by this utility model are as follows: the above-mentioned double optical wedge structure enables direct detection of the zenith direction, achieving the purpose of direct scanning of the east, south, west, north, and zenith directions, and realizing accurate wind speed detection in the east, south, west, north, and zenith directions. At the same time, the required size of the optical tube is significantly reduced in terms of structure. Furthermore, by changing the rotation direction of the two optical wedges to opposite directions, an approximate planar scanning mode that cannot be achieved by a single optical wedge can be realized. Compared with the double reflector scanning device, the device of this application only requires one drive motor, and is also simpler in terms of structure and control logic. Attached Figure Description
[0020] Figure 1 This is a cross-sectional view of the optical scanning device of this utility model;
[0021] Figure 2 This is a schematic diagram of the co-directional structure of the optical scanning device of this utility model;
[0022] Figure 3 This is a schematic diagram of the reverse structure of the optical scanning device of this utility model;
[0023] Figure 4 This is a schematic diagram of DBS5 beam scanning.
[0024] Figure 5 This is a schematic diagram of an elevation angle plane scan;
[0025] Figure 6 This is a schematic diagram of a handheld planar scanner;
[0026] Figure 7 The simulation diagram of the scanning trajectory in Example 1
[0027] Figure 8 This is a simulation diagram of the X-coordinate change in Example 1;
[0028] Figure 9 This is a simulation diagram of the Y-coordinate change in Example 1;
[0029] Figure 10 The simulation diagram of the scanning trajectory in Example 2
[0030] Figure 11 This is a simulation diagram of the reverse transformation of the X-coordinate in Example 2;
[0031] Figure 12 This is a simulation diagram of the Y-coordinate change in Example 2;
[0032] Figure 13 This is a simulation diagram of the positive change of the X-coordinate in Example 2.
[0033] [Attached image labels]
[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 Implementation
[0035] To make the above-mentioned objectives, features, and advantages of this utility model more readily understood, the specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.
[0036] This utility model discloses an optical scanning device for a compact wind-measuring lidar, combined with Figure 1 As shown, the device is provided with a frame 1, on which a first gear 2 and a second gear 3 are rotatably mounted. A first optical wedge 4 is installed in the first gear 2, and a second optical wedge 5 is installed in the second gear 3. The wedge angles of the first optical wedge 4 and the second optical wedge 5 are equal.
[0037] A drive motor 7 is connected to a transmission shaft 71. A first transmission gear 8 and a second transmission gear 9 are sequentially arranged on the transmission shaft 71. The first transmission gear 8 meshes with the first gear 2, and the second transmission gear 9 meshes with the second gear 3.
[0038] Driven by the drive motor 7, the first optical wedge 4 and the second optical wedge 5 rotate in the same direction at a differential speed or in opposite directions at a differential speed.
[0039] The frame 1 is equipped with a lens barrel 6, and a lens and a reflector 62 are installed inside the lens barrel 6. The emitted light of the lidar passes through the reflector 62, the lens, the second optical wedge 5 and the first optical wedge 4 in sequence before being emitted.
[0040] It should be pointed out that, in combination Figure 1As shown, the inclined surfaces of the first optical wedge 4 and the second optical wedge 5 are arranged opposite each other. Alternatively, the inclined surfaces of the first optical wedge 4 and the second optical wedge 5 can also be arranged facing downwards in the same direction (towards the lens barrel 60). These two inclined surface arrangements affect the initial angle of the two optical wedges in their initial state, but do not affect the final technical effect. The first gear 2 and the second gear 3 are arranged parallel to each other, as are the first optical wedge 4 and the second optical wedge 5. The first optical wedge 4 and the second optical wedge 5 are quartz glass optical wedges, and their wedge angle is 15 degrees. Figure 4 As shown, when performing DBS5 beam scanning, this application will perform scanning in the east, south, west, north, and zenith directions. The zenith is the Z-axis direction. The scanning beam circles around the Z-axis and forms a scanning range. The angle between the scanning beam and the Z-axis (zenith angle) is related to the wedge beams of the first and second optical wedges. When the wedge angle is 15 degrees, the zenith angle is 30 degrees.
[0041] Specifically, the gear ratio of the first gear 2 and the second gear 3 is 20:19. Figure 1 The first gear 2 has 100 teeth, the second gear 3 has 95 teeth, and the first transmission gear 8 and the second transmission gear 9 are bevel gears with a tooth ratio of 1:1. Figure 1 Both of them have 18 teeth. By changing 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 rotate in the same direction or in opposite directions at different speeds.
[0042] Specifically, the co-directional structure is as follows: when the first optical wedge 4 and the second optical wedge 5 rotate at different speeds in the same direction, the structure of the device in this 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 meshes on the upper side of the second transmission gear 9, and the drive 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 in opposite directions at different speeds, the structure of the device in this application is as follows: Figure 3 As shown, the second gear 3 meshes on the lower side of the second transmission gear 9, and the rest of the structure is basically the same as the above-mentioned same-direction structure.
[0044] Furthermore, combining Figure 2 , Figure 3 As shown, in order to improve the smoothness of the scanning device during operation, a first bearing 10 is provided between the frame 1 and the first gear 2, a third bearing 12 is provided between the frame 1 and the second gear 3, and a second bearing 11 is provided between the first gear 2 and the second gear 3.
[0045] Specifically, in combination Figures 1-3 As shown, the lens includes a first lens 60 and a second lens 61, with the first lens 60 close to the second optical wedge 5 and the second lens 61 close to the reflector 62.
[0046] Example 1, combined with Figure 2 As shown, in the above-mentioned co-directional structure, the emitted light is collimated and passes through the reflector 62 and sequentially enters the second lens 61, the first lens 60, the second light wedge 5, and the first light wedge 4. The parameters are set as follows: the wedge angle of the two light 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 light wedge 4 and the second light wedge 5 rotate in the same direction at a different speed. In the initial state, the inclined surfaces of the first light wedge 4 and the second light wedge 5 are parallel.
[0047] During operation, the first and second optical wedges rotate under the drive of 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 differ. The normal direction of the inclined plane of the optical wedge rotates with the optical wedge, and the direction of the refracted beam will also rotate with the rotation of the optical wedge.
[0048] For VAD or DBS4 scanning, a 360-degree VAD or DBS4 scan with a zenith angle of 30 degrees can be achieved when the first optical wedge 4 rotates 360 degrees. 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, thus achieving scanning in the zenith direction, i.e., a DBS5 scan with a zenith angle of 30 degrees. (For more information on DBS5 scanning, please refer to...) Figure 4 As shown, the specific scanning trajectory is as follows: Figure 7 As shown, from Figure 7 The beam exhibits an approximately circular trajectory and a dotted trajectory at the center; the line graph showing the change in the X-coordinate of the scanning point corresponding to the beam and the rotation angle of the first optical wedge 4 is shown below. Figure 8 As shown in the figure, the line graph showing the change in the Y coordinate of the scanning point corresponding to the beam and the rotation angle of the first optical wedge 4 is as follows. Figure 9 As shown, combined with Figures 7-9 Initially, the coordinates of the scanning point are (30, 0). The device scans counterclockwise. When the first optical wedge 4 rotates 360 degrees, it 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 a 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 approaches 3600 degrees, the X-axis coordinate of the scanning point will eventually be equal to 0, thus achieving scanning of the zenith direction.
[0049] When performing planar scanning, the scanning method of the device is as follows: Figure 5 , Figure 6 As shown, based on Embodiment 1, the first optical wedge 4 is rotated 4 degrees independently, so that the second optical wedge 5 lags behind the first optical wedge 4 degrees in the subsequent synchronous drive. 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 rotates 180 degrees, a planar scanning range with an included angle of approximately 60 degrees can be obtained (approximately 30 degrees on one side and 60 degrees on both sides).
[0050] Example 2, combined with Figure 3 As shown, in the above-mentioned reverse structure, the emitted light is collimated and passes through the reflector 62 and sequentially enters the second lens 61, the first lens 60, the second optical wedge 5, and the first optical wedge 4. 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 different speeds.
[0051] Assume the first optical wedge 4 rotates clockwise and the second optical wedge 5 rotates counterclockwise. With the inclined planes of the first optical wedge 4 and the second optical wedge 5 parallel as the reference state, in this reference state, the second optical wedge 5 first rotates 4 degrees in the opposite direction (that is, the second optical wedge 5 first rotates 4 degrees clockwise) and the state after completing the 4-degree rotation is the initial state.
[0052] For approximate planar scanning, when the first optical wedge 4 rotates 180 degrees, it completes a planar scanning range with an included angle of approximately 30 degrees. The specific scanning trajectory is as follows: Figure 10 As shown, an approximate planar scanning range of 30° can be obtained. The line graph showing the change in the X-coordinate of the scanning point corresponding to the beam versus the rotation angle of the first optical wedge 4 is shown below. Figure 11 , Figure 13 As shown in the figure, the line graph showing the change in the Y coordinate of the scanning point corresponding to the beam and the rotation angle of the first optical wedge 4 is as follows. Figure 12 As shown, for easy comparison of forward and reverse rotation, Figure 11 For the first optical wedge 4 to rotate in the positive direction, Figure 12 The first optical wedge 4 rotates in the opposite direction. Figure 13 The first optical wedge 4 rotates in the opposite direction;
[0053] Combination Figure 10 , Figure 12 , Figure 13As shown, the scanning angle of the scanning point changes from horizontal -30 degrees to 30 degrees, with a total range of 60 degrees. The pitch angle changes by about 2 degrees, thus achieving approximate planar scanning and satisfying handheld planar scanning and a certain angle of elevation planar scanning.
[0054] In summary, the aforementioned dual-wedge structure enables direct detection of the zenith direction, achieving direct scanning of the east, south, west, north, and zenith directions, thus enabling accurate wind speed detection in these directions. Furthermore, it significantly reduces the required size of the optical tube. Moreover, by reversing the rotation directions of the two wedges, an approximate planar scanning mode, impossible with a single wedge, can be achieved. Compared to dual-mirror scanning devices, the device in this application requires only one drive motor and is simpler in structure and control logic.
[0055] The embodiments described above are merely illustrative of one or more implementations of this utility model, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the appended claims.
Claims
1. An optical scanning device for a compact wind-measuring lidar, the device being provided with a frame, characterized in that, The frame is rotatably mounted with a first gear and a second gear. A first optical wedge is installed inside the first gear, and a second optical wedge is installed inside the second gear. The wedge angles of the first optical wedge and the second optical wedge are equal. A drive motor is connected to a transmission shaft, on which a first transmission gear and a second transmission gear are sequentially arranged. The first transmission gear meshes with the first gear, and the second transmission gear meshes with the second gear. Driven by the drive motor, the first optical wedge and the second optical wedge rotate in the same direction at a differential speed or in opposite directions at a differential speed. The frame is equipped with a lens barrel, and a lens and a reflector are installed inside the lens barrel. The emitted light of the lidar passes through the reflector, the lens, the second optical wedge, and the first optical wedge in sequence before being emitted.
2. The optical scanning device for the compact wind-measuring lidar according to claim 1, characterized in that, The first gear and the second gear are arranged in parallel, and the first optical wedge and the second optical wedge are arranged in parallel.
3. The optical scanning device for the compact wind-measuring lidar according to claim 1 or 2, characterized in that, The first and second optical wedges are quartz glass optical wedges, and the wedge angle of the first and second optical wedges is 15 degrees.
4. The optical scanning device for the compact wind-measuring lidar according to claim 3, characterized in that, The gear ratio between the first gear and the second gear is 20:19, and the gear ratio between the first transmission gear and the second transmission gear is 1:
1.
5. The optical scanning device for the compact wind-measuring lidar according to claim 1, characterized in that, A first bearing is provided between the frame and the first gear, and a third bearing is provided between the frame and the second gear.
6. The optical scanning device for the compact wind-measuring lidar according to claim 1 or 5, characterized in that, A second bearing is provided between the first gear and the second gear.
7. The optical scanning device for the compact wind-measuring lidar according to claim 1, characterized in that, The lens includes 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 for the compact wind-measuring lidar according to claim 1, characterized in that, The inclined surface of the first optical wedge is positioned opposite to or in the same downward direction as the inclined surface of the second optical wedge.