Special-shaped multi-faceted rotating mirror

Abstract

This invention provides an irregularly shaped multifaceted rotating mirror, comprising: a rotating mirror body, a rotating axis, and a counterweight structure. The rotating axis is disposed on the rotating mirror body, and the rotating mirror body has multiple reflecting surfaces, each with a positive and distinct angle to the rotating axis. The counterweight structure is disposed on the rotating mirror body for counterweight compensation. This irregularly shaped multifaceted rotating mirror integrates horizontal and vertical scanning into a single rotating mirror element. It achieves multi-zone stitching of the vertical field of view by relying on the differentiated angles between the reflecting surfaces and the rotating axis, eliminating the need for additional mirrors and drive structures, effectively reducing system complexity and production costs. Simultaneously, it balances optical design freedom and dynamic balance performance. The different positive tilt angles of each reflecting surface allow for flexible matching of vertical deflection requirements, and the counterweight corrects the center of mass to the rotating axis. Furthermore, a fine-tuning structure is incorporated to compensate for manufacturing errors, allowing for precise adjustment based on measured data, improving dynamic balance accuracy, and ensuring consistency in mass production.

Description

Technical Field

[0001] This invention relates to the field of lidar scanning and reflector technology, and in particular to an irregularly shaped multifaceted rotating mirror. Background Technology

[0002] Currently, in lidar scanning applications, a scheme using irregularly shaped multi-faceted rotating mirrors to achieve vertical field-of-view stitching is adopted. By designing different angles between each reflective surface and the rotation axis, horizontal scanning and vertical deflection functions can be completed simultaneously on a single rotating mirror, eliminating the need for a separate mirror assembly.

[0003] However, when it is necessary to stitch together a large vertical field of view (such as 90°), the tilt angles of the various reflecting surfaces differ significantly, leading to the following technical problems with the rotating mirror:

[0004] First, the dynamic balance performance deteriorates, and the tilt angles of each reflective surface are greatly different, resulting in uneven mass distribution of the rotating mirror in different orientations. The center of mass deviates from the rotation axis, and the moment of inertia is not symmetrically distributed along the rotation axis. When the rotating mirror rotates at high speed, it generates periodic vibration and torque fluctuation, which affects the scanning stability and point cloud accuracy. Long-term operation may also lead to bearing wear and a decrease in system reliability.

[0005] Secondly, the manufacturing process is difficult. Multi-faceted rotating mirrors with large angle differences are typical asymmetric complex curved surface optical elements. Precise control of the angle between each reflecting surface and the rotation axis is difficult, resulting in low processing yield and high cost. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an irregularly shaped multi-faceted rotating mirror to solve the problems of how to balance horizontal wide field of view scanning and large-scale vertical field of view expansion in the prior art, as well as the problems of uneven quality and eccentricity imbalance of irregularly shaped tilting rotating mirrors.

[0007] To achieve the above and other related objectives, the present invention provides an irregularly shaped multifaceted rotating mirror, comprising:

[0008] The rotating mirror body, the rotating shaft, and the counterweight structure, among which,

[0009] The rotation axis is disposed on the rotating mirror body, wherein the rotating mirror body has One reflective surface, Furthermore, the angles between each of the aforementioned reflective surfaces and the rotation axis are all positive and distinct from one another;

[0010] The counterweight structure is installed on the rotating mirror body and is used for counterweight compensation.

[0011] In one embodiment of the present invention, the compensation mass provided by the counterweight structure satisfies the following calculation formula, wherein the calculation formula is:

[0012] ;

[0013] in, To compensate for quality, The effective radius of the counterweight structure is... The density of the rotating mirror body material, This represents the total missing material volume of the reflective surface. The equivalent centroid radius of the missing part of the material.

[0014] In one embodiment of the present invention, each of the reflective surfaces corresponds to a fixed vertical field of view partition, and the vertical fields of view of each partition are arranged continuously and overlapped, for splicing together to form a complete vertical field of view.

[0015] In one embodiment of the present invention, the first The angle between the reflecting surface and the rotation axis is And the first The vertical deflection angle corresponding to each of the aforementioned reflective surfaces is: , The vertical deflection angle of each of the aforementioned reflective surfaces covers the total vertical field of view, wherein... , This represents the number of reflective surfaces.

[0016] In one embodiment of the present invention, the total missing material volume corresponding to the reflective surface ,in, This represents the total missing material volume of the reflective surface. For the first The material removal volume corresponding to the aforementioned reflective surface. This represents the number of reflective surfaces.

[0017] In one embodiment of the present invention, when the rotating mirror body rotates one revolution, Each of the aforementioned reflective surfaces sequentially scans across the horizontal field of view to form a complete point cloud, wherein each of the aforementioned reflective surfaces has the same effective mechanical scanning angle range in the horizontal direction. And the horizontal field of view is .

[0018] In one embodiment of the present invention, the counterweight structure includes a counterweight block, which is integrally formed or independently installed on the side opposite to the cumulative mass effect of the rotating mirror body and the reflecting surface. The density of the counterweight block is greater than the material density of the rotating mirror body. The mass and distribution position of the counterweight block are calculated and determined based on the total mass of the material removed from each reflecting surface and the centroid offset.

[0019] In one embodiment of the present invention, the counterweight structure includes an asymmetric matrix material, wherein the asymmetric matrix material is disposed in the non-reflective region of the rotating mirror body.

[0020] In one embodiment of the present invention, the irregularly shaped multifaceted rotating mirror further includes a fine-tuning structure disposed inside the rotating mirror body or on its end face.

[0021] In one embodiment of the present invention, the fine-tuning structure includes one of a micro counterweight hole, a local weight reduction groove, or a detachable balance screw.

[0022] As described above, the irregularly shaped multifaceted rotating mirror of the present invention has the following beneficial effects:

[0023] First, the present invention integrates vertical and horizontal scanning functions into a single rotating mirror element. By designing different angles between each reflective surface and the rotation axis, it directly realizes multi-zone stitching of the vertical field of view without the need for additional tilting mirrors and their drive control units, which greatly reduces the system complexity and cost.

[0024] Second, taking into account both the freedom of optical design and dynamic balance performance, this invention allows all reflective surfaces to have positive and different tilt angles, which meets the flexible configuration requirements of the optical system for vertical deflection angle. At the same time, the center of mass is corrected to the rotation axis through the counterweight compensation structure, which solves the problem of dynamic balance deterioration caused by unidirectional mass accumulation.

[0025] Third, it has the ability to compensate for processing errors. By setting micro-counterweight holes, balance screws and other fine-tuning structures, it can be finely adjusted according to the measured dynamic balance data after the rotating mirror is processed, further improving the dynamic balance accuracy and ensuring batch production consistency. Attached Figure Description

[0026] Figure 1 The diagram shows a scanning field of view of the irregularly shaped multifaceted rotating mirror of the present invention in one embodiment;

[0027] Figure 2 The image shown is a top-view scanning schematic diagram of the irregularly shaped multifaceted rotating mirror of the present invention in one embodiment;

[0028] Figure 3 The diagram shows the distribution of the mass and moment of inertia of the irregular multifaceted rotating mirror in one embodiment of the present invention.

[0029] Figure 4 The following are three views of the counterweight structure of the irregular multifaceted rotating mirror of the present invention in one embodiment;

[0030] Figure 5 The following are three views of the counterweight structure in one embodiment of the irregularly shaped multifaceted rotating mirror of the present invention;

[0031] Figure 6 The image shown is a three-view drawing of the fine-tuning structure of the irregular multifaceted rotating mirror of the present invention in one embodiment. Detailed Implementation

[0032] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0033] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0035] In light of the shortcomings of existing technologies described in the background section, how to maintain a wide horizontal field of view while achieving a large-scale expansion of the vertical field of view, and taking into account the engineering difficulties of system manufacturing, has become one of the key issues in the development of irregularly shaped rotating mirror scanning lidar technology. Therefore, this invention proposes an irregularly shaped multi-faceted rotating mirror, with the main innovations being: First, a dynamic balance compensation method under unidirectional tilt angle configuration. For irregularly shaped rotating mirrors where all reflective surfaces have positive and different tilt angles, a mass compensation scheme based on the asymmetric retention of counterweights or matrix materials on the opposite side is proposed to solve the dynamic balance problem caused by unidirectional mass accumulation. Second, a quantitative calculation method for counterweight mass. A formula for calculating counterweight mass based on material removal volume, equivalent centroid radius, and counterweight action radius is established to achieve precise design of the counterweight structure.

[0036] Specifically, the present invention provides an irregularly shaped multifaceted rotating mirror, comprising:

[0037] The rotating mirror body, the rotating shaft, and the counterweight structure, among which,

[0038] The rotation axis is disposed on the rotating mirror body, wherein the rotating mirror body has One reflective surface, Furthermore, the angles between each of the aforementioned reflective surfaces and the rotation axis are all positive and distinct from one another;

[0039] The counterweight structure is installed on the rotating mirror body and is used for counterweight compensation.

[0040] It should be noted that, in this embodiment, each reflective surface corresponds to a fixed vertical field of view partition. The vertical fields of view of each partition are arranged continuously and overlap, and are used to stitch together a complete vertical field of view. Each reflective surface forms a different angle with the rotation axis, so that each reflective surface has a different deflection angle in the vertical direction. The angles between each reflective surface and the rotation axis are positive and different, in order to meet the design requirements of the optical system for the vertical deflection angle. The angle between the reflecting surface and the rotation axis is And the first The vertical deflection angle corresponding to each of the aforementioned reflective surfaces is: , The vertical deflection angle of each of the aforementioned reflective surfaces covers the total vertical field of view, wherein... , This represents the number of reflective surfaces.

[0041] Furthermore, in this embodiment, the total missing material volume corresponding to the reflective surface... ,in, This represents the total missing material volume of the reflective surface. For the first The material removal volume corresponding to the aforementioned reflective surface. This represents the number of reflective surfaces.

[0042] Furthermore, in this embodiment, when the rotating mirror body rotates one revolution, Each of the aforementioned reflective surfaces sequentially scans across the horizontal field of view to form a complete point cloud, wherein each of the aforementioned reflective surfaces has the same effective mechanical scanning angle range in the horizontal direction. And the horizontal field of view is .

[0043] Specifically, in this embodiment, with For example, Figure 1 and Figure 2 As shown, Figure 1 Displayed as a schematic diagram of the scanned field of view. Figure 2 The image is displayed as a top-down view of the scan, where the desired horizontal field of view is set. Vertical field of view The rotating mirror body has four reflecting surfaces, and the angles between each reflecting surface and the rotation axis are respectively... Assuming the incident light direction of the laser transceiver module is fixed, Let the angle be the incident vertical field of view angle, then the corresponding vertical deflection angle of each reflecting surface is: To achieve 90° vertical field of view coverage, the deflection angles of the four reflective surfaces need to cover a 90° range, for example, corresponding to -37.5°, -12.5°, 12.5°, and 37.5° respectively. Then, the angles between each reflective surface and the rotation axis are -18.75°, -6.25°, 6.25°, and 18.75° respectively (the negative sign indicates that the tilt direction is opposite).

[0044] Furthermore, in this embodiment, the effective mechanical scanning angle of each reflective surface in the horizontal direction is... Corresponding to the imaging window, there is a transition area between adjacent reflective surfaces to avoid crosstalk. The rotation speed of the rotating mirror body is set to "600 rpm", then the time per revolution is "100 ms", each reflective surface occupies a time window of "25 ms", and the frame rate is "10 Hz".

[0045] Furthermore, such as Figure 3 As shown, the diagram illustrates the distribution of mass and moment of inertia of the rotating mirror. In order to achieve different tilt angles of the reflecting surface, the mass of the rotating mirror body is not uniformly distributed along the rotation axis, and its principal axis of inertia does not coincide with the rotation axis. This will cause force imbalance and torque imbalance of the rotating mirror. During rotation, reciprocating force and torque will be generated, causing vibration. Therefore, in order to achieve high-speed and stable rotation for lidar scanning, this invention adopts at least one of two counterweight compensation methods to achieve dynamic balance.

[0046] Specifically, in this embodiment, taking the counterweight block of the counterweight structure as an example, such as... Figure 4 As shown, the counterweight is integrally formed or independently installed on the side opposite to the cumulative mass effect of the reflective surface of the rotating mirror body. The density of the counterweight is greater than the density of the rotating mirror body material. The mass and distribution position of the counterweight are calculated and determined based on the total mass of the material removed from each reflective surface and the centroid offset, so that the centroid of the rotating mirror body returns to the rotation axis.

[0047] Specifically, in another embodiment of the invention, the counterweight structure includes an asymmetric matrix material, wherein the asymmetric matrix material is disposed in the non-reflective region of the rotating mirror body.

[0048] It should be noted that, in this embodiment, as Figure 5 As shown, in the non-reflective area of ​​the rotating mirror body, an asymmetrical substrate profile is designed so that more substrate material is retained as a natural counterweight on the opposite side of the side where more reflective surface mass is removed. The design of the substrate profile must meet the requirements of dynamic balance calculations while not interfering with optical path propagation and system installation.

[0049] In one embodiment of the present invention, the compensation mass provided by the counterweight structure satisfies the following calculation formula, wherein the calculation formula is:

[0050] ;

[0051] in, To compensate for quality, The effective radius of the counterweight structure is... The density of the rotating mirror body material, This represents the total missing material volume of the reflective surface. The equivalent centroid radius of the missing part of the material.

[0052] It should be noted that, in this embodiment, the compensation mass provided by the counterweight structure... Must meet ,in, To compensate for quality, The effective radius of the counterweight structure is... The density of the rotating mirror body material, This represents the total missing material volume of the reflective surface. Let be the equivalent centroid radius of the missing material portion. Thus, in application, the required correction mass and installation position for biplane balancing can be determined using the coefficient method.

[0053] In one embodiment of the present invention, the irregular multifaceted rotating mirror further includes a fine-tuning structure disposed inside the rotating mirror body or on its end face.

[0054] It should be noted that, in this embodiment, the fine-tuning structure includes one of the following: a micro-counterweight hole, a local weight-reducing groove, or a detachable balancing screw, such as... Figure 6 As shown, taking a detachable balancing screw as an example, the three-view diagram of the fine-tuning structure is shown. The fine-tuning structure is also provided inside or on the end face of the rotating mirror body to compensate for the residual imbalance caused by the machining error. Correspondingly, the fine-tuning structure can also be represented as a micro counterweight hole or a local weight reduction groove. The position and number of the micro counterweight hole are determined according to the measured dynamic balance data after the rotating mirror is machined.

[0055] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0056] In summary, the irregularly shaped multifaceted rotating mirror of this invention integrates horizontal and vertical scanning into a single rotating mirror element. It achieves multi-zone stitching of the vertical field of view by relying on the different angles between the reflecting surfaces and the rotation axis, eliminating the need for additional mirrors and drive structures, effectively reducing system complexity and production costs. At the same time, it takes into account both optical design freedom and dynamic balance performance. The positive tilt angles of each reflecting surface are different, which can flexibly match vertical deflection requirements, and the center of mass is corrected to the rotation axis with the help of counterweights. In addition, a fine-tuning structure is set up to compensate for processing errors, and precise adjustment is made based on actual measurement data to improve dynamic balance accuracy and ensure consistency in mass production.

[0057] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An irregularly shaped multifaceted rotating mirror, characterized in that, include: The rotating mirror body, the rotating shaft, and the counterweight structure, among which, The rotation axis is disposed on the rotating mirror body, wherein the rotating mirror body has One reflective surface, Each of the aforementioned reflective surfaces makes a positive angle with the rotation axis, and these angles are all different from each other. Each of the reflective surfaces corresponds to a fixed vertical field of view partition, and the vertical fields of view of each partition are arranged continuously and overlapped, in order to be stitched together to form a complete vertical field of view. The counterweight structure is disposed on the rotating mirror body for counterweight compensation, so that the center of mass of the rotating mirror body returns to the rotation axis; and A fine-tuning structure is provided inside the rotating mirror body or on its end face to compensate for machining errors.

2. The irregularly shaped multifaceted rotating mirror according to claim 1, characterized in that, The compensation mass provided by the counterweight structure satisfies the following calculation formula, wherein the calculation formula is: ； in, To compensate for quality, The effective radius of the counterweight structure is... The density of the rotating mirror body material, This represents the total missing material volume of the reflective surface. The equivalent centroid radius of the missing part of the material.

3. The irregularly shaped multifaceted rotating mirror according to claim 1, characterized in that, No. The angle between the reflecting surface and the rotation axis is And the first The vertical deflection angle corresponding to each of the aforementioned reflective surfaces is: , The vertical deflection angle of each of the aforementioned reflective surfaces covers the total vertical field of view, wherein... , This represents the number of reflective surfaces.

4. The irregularly shaped multifaceted rotating mirror according to claim 1, characterized in that, The total missing material volume corresponding to the reflective surface ,in, This represents the total missing material volume of the reflective surface. For the first The material removal volume corresponding to the aforementioned reflective surface. This represents the number of reflective surfaces.

5. The irregularly shaped multifaceted rotating mirror according to claim 1, characterized in that, When the rotating mirror body rotates one revolution Each of the aforementioned reflective surfaces sequentially scans the horizontal field of view to form a complete point cloud, wherein each of the aforementioned reflective surfaces has the same effective mechanical scanning angle range in the horizontal direction. And the horizontal field of view is .

6. The irregularly shaped multifaceted rotating mirror according to claim 1, characterized in that, The counterweight structure includes a counterweight block, which is integrally formed or independently installed on the side opposite to the cumulative mass effect of the rotating mirror body and the reflecting surface. The density of the counterweight block is greater than the density of the rotating mirror body material. The mass and distribution position of the counterweight block are calculated and determined based on the total mass of the material removed from each reflecting surface and the centroid offset.

7. The irregularly shaped multifaceted rotating mirror according to claim 1, characterized in that, The counterweight structure includes an asymmetric matrix material, wherein the asymmetric matrix material is disposed in the non-reflective region of the rotating mirror body.

8. The irregularly shaped multifaceted rotating mirror according to claim 1, characterized in that, The fine-tuning structure includes one of a micro counterweight hole, a local weight reduction groove, or a detachable balance screw.

Images