Rotary distance measuring device

Abstract

The utility model discloses a rotary distance measuring device, and the device comprises a base which is fixedly provided with a signal transmitting module and a signal receiving module; the reflecting mirror assembly is rotatably arranged on the base; a marker is arranged on the periphery of the reflector assembly around the rotating axis of the reflector assembly, and the marker is arranged to be capable of reflecting the measuring light reflected by the reflector assembly back to the reflector assembly and reflecting the measuring light to the signal receiving module through the reflector assembly. According to the embodiment of the invention, the reflector assembly is set to be rotatable, and the reflector assembly is not connected with any signal line and power line, so that the rotation of the reflector assembly is not limited, and 360-degree continuous rotation can be realized. Meanwhile, errors caused by temperature changes can be obtained in real time and compensated by setting the marker and continuously measuring the marker, the measurement precision can be effectively improved by calibrating the marker, and compared with a complex temperature compensation algorithm, the setting of the marker calibration is relatively simple in hardware and software implementation.

Description

Technical Field

[0001] The present application relates to the field of optical detection technology, and in particular to a rotary distance measuring device. Background Art

[0002] In recent years, with the continuous development of artificial intelligence, robotics, and sensor technologies, cleaning robots have become increasingly intelligent and functional. Among them, LiDAR technology has played an important role in promoting the development of cleaning robots.

[0003] The measurement accuracy of LiDAR is affected by many factors, among which temperature change is a significant one. Temperature changes can cause changes in the physical properties of LiDAR's internal components, thus affecting the measurement results.

[0004] The main impacts include:

[0005] Laser wavelength change: Temperature changes can cause the laser wavelength to drift, thus affecting the ranging accuracy.

[0006] Deformation of optical components: Temperature changes can cause the size and shape of optical components (such as lenses and prisms) to change, affecting the propagation path of the light beam.

[0007] Changes in electronic component performance: Temperature changes can affect the performance of electronic components (such as ADC and DAC), leading to measurement errors. These errors can cause inaccurate LiDAR measurement results and affect their use. Utility Model Content

[0008] The purpose of the embodiments of the present application is to provide a rotation distance measuring device that can solve the above-mentioned problems existing in the prior art.

[0009] To achieve the above objectives, this application adopts the following technical solutions:

[0010] A rotary distance measuring device is provided, comprising:

[0011] A base, on which a signal transmitting module and a signal receiving module are fixedly mounted;

[0012] a reflector assembly rotatably disposed on the base;

[0013] A marker is provided on the periphery of the reflector assembly around the rotation axis of the reflector assembly. The marker is configured to reflect the measuring light reflected by the reflector assembly back to the reflector assembly and then reflect the measuring light to the signal receiving module via the reflector assembly.

[0014] Optionally, there are multiple markers, and the multiple markers are evenly arranged around the circumference of the reflector assembly.

[0015] Optionally, at least two of the markers have different vertical distances from the axis of rotation of the reflector assembly.

[0016] Optionally, a protective cover is further included which is arranged outside the reflector assembly. The protective cover is fixedly connected to the base and is made of a transparent material.

[0017] Optionally, the marker is a calibration block fixed in position relative to the base.

[0018] Optionally, the marker is a calibration coating applied on the protective cover.

[0019] Optionally, the reflector assembly has a transmission signal reflection area and a reception signal reflection area, and the signal transmission module and the signal reception module are located on the same side of the reflector assembly and are not coaxially arranged;

[0020] The transmission signal reflection area is arranged corresponding to the signal transmission module, and the reception signal reflection area and the signal receiving module are both arranged around the rotation axis of the reflector assembly.

[0021] Optionally, the reflector assembly includes a first reflector lens and a second reflector lens, and the first reflector lens and the second reflector lens are arranged perpendicular to each other and are both located on the rotation axis of the reflector assembly.

[0022] Optionally, the size of the second reflective lens is larger than that of the first reflective lens, the first reflective lens and the second reflective lens partially overlap in the vertical direction, the area of the second reflective lens corresponding to the first reflective lens in the vertical direction is a hollow area, and a receiving signal reflection area is formed on the second reflective lens and located around the hollow area.

[0023] Optionally, the reflector assembly includes a semi-transparent and semi-reflective mirror, and the semi-transparent and semi-reflective mirror is configured to reflect part of the detection light and transmit part of the detection light.

[0024] The beneficial effects of the present application are as follows: In the embodiment of the present application, by setting the reflector assembly to be rotatable, since no signal lines or power lines are connected to it, its rotation is unrestricted, and 360° continuous rotation can be achieved. The rotation of the reflector assembly can adjust the direction in which the measurement light emitted by the signal transmission module is reflected, thereby achieving 360° rotation measurement. At the same time, by setting a marker and continuously measuring the marker, the error caused by temperature changes can be obtained in real time and compensated. Marker calibration can effectively improve measurement accuracy. Compared with complex temperature compensation algorithms, calibration by setting a marker is relatively simple in hardware and software implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present application is further described in detail below with reference to the accompanying drawings and examples.

[0026] Figure 1 This is a schematic diagram of the overall structure of the rotary distance measuring device according to one embodiment of the present application;

[0027] Figure 2 This is a schematic diagram of the overall structure of a rotary distance measuring device according to another embodiment of the present application;

[0028] Figure 3 This is a schematic diagram of the overall structure of a rotary distance measuring device according to another embodiment of the present application;

[0029] Figure 4 This is a structural schematic diagram of a plurality of markers installed on the inner side of a protective cover according to an embodiment of the present application.

[0030] In the picture:

[0031] 100, base; 110, protective cover; 120, signal transmitting module; 130, signal receiving module; 140, marker; 210, first reflective lens; 220, second reflective lens; 221, hollow area; 230, transmitting signal reflection area; 240, receiving signal reflection area; 250, semi-transparent and semi-reflective mirror; 300, drive motor; 410, code disk; 420, magnet; 500, object to be measured. DETAILED DESCRIPTION

[0032] To make the technical problems solved by this application, the technical solutions adopted, and the technical effects achieved more clearly, the technical solutions of the embodiments of this application are further described in detail below. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of this application.

[0033] In the description of this application, unless otherwise specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections; direct connections, or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0034] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0035] In the description herein, it should be understood that the terms "upper," "lower," "left," "right," and other positions or relationships are used solely for ease of description and simplified operation, and are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0036] Throughout this specification, references to terms such as "one embodiment" and "example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example.

[0037] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0038] LiDAR is an active remote sensing technology that determines the distance to a target by emitting laser pulses and measuring the time it takes for the reflected light to return to the sensor. LiDAR provides highly accurate, real-time three-dimensional information about the surrounding environment, making it ideal for environmental perception and navigation in cleaning robots.

[0039] During operation, the laser radar needs to rotate as large an angle as possible to efficiently determine information about surrounding objects. In the existing technology, the rotation of the laser radar needs to be achieved through the rotation of the signal transceiver module. However, since the signal transceiver module is usually connected to a signal line and a power line, in order to avoid wire entanglement, the rotation detection angle of the laser radar is usually limited.

[0040] At the same time, the measurement accuracy of LiDAR is affected by many factors, among which temperature change is a significant factor. Temperature changes can cause changes in the physical properties of LiDAR's internal components, thus affecting the measurement results.

[0041] The main impacts include:

[0042] Laser wavelength change: Temperature changes can cause the laser wavelength to drift, thus affecting the ranging accuracy.

[0043] Deformation of optical components: Temperature changes can cause the size and shape of optical components (such as lenses and prisms) to change, affecting the propagation path of the light beam.

[0044] Changes in electronic component performance: Temperature changes can affect the performance of electronic components (such as ADCs and DACs), leading to measurement errors.

[0045] Existing solutions usually solve the above problems through temperature compensation. Specifically, a temperature sensor is integrated inside the lidar to monitor the working environment temperature in real time; a dedicated temperature compensation circuit is designed to adjust parameters such as the laser drive current and ADC sampling rate based on the temperature information fed back by the temperature sensor to offset the impact of temperature.

[0046] However, the temperature compensation method has the following problems:

[0047] The uneven temperature field and uneven temperature distribution within the lidar make the establishment of a temperature compensation model complex. The coupling of multiple factors, such as temperature changes and other factors (such as vibration and aging), increases the difficulty of compensation. The real-time requirement for temperature compensation places high demands on the system's computing power.

[0048] In summary, the temperature compensation solution has many problems in terms of product structure and measurement accuracy.

[0049] Based on the above situation, there is an urgent need to provide a laser radar that can avoid wire winding interference during the rotation detection process, which can achieve rotation scanning at the largest possible angle and provide a different solution to the problem that the measurement accuracy of the laser radar is affected by temperature.

[0050] Reference Figure 1-3As shown, an embodiment of the present application provides a rotary distance measuring device, comprising: a base 100 for mounting the rotary distance measuring device on a device to be used, on which a signal transmitting module 120 and a signal receiving module 130 are fixedly disposed; the signal transmitting module 120 is configured to generate a measuring beam, and the signal receiving module 130 receives the reflected measuring beam. By measuring the time difference between the emission of the measuring beam and the reception of the reflected measuring beam, the distance of the object to be measured 500 can be calculated; a reflector assembly rotatably disposed on the base 100, for guiding a laser beam to scan a target area, thereby obtaining position information of the object to be measured 500. The reflector assembly can realize various scanning modes such as line scanning and surface scanning of the target area by controlling the rotation speed and angle of the reflector; a marker 140 is disposed around the periphery of the reflector assembly and around the rotation axis of the reflector assembly. The marker 140 is configured to reflect the measuring light reflected by the reflector assembly back to the reflector assembly and reflect it to the signal receiving module 130 via the reflector assembly.

[0051] In the embodiment of the present application, the reflector assembly is configured to be rotatable. Since no signal lines or power lines are connected to it, its rotation is unrestricted, and 360° continuous rotation can be achieved. The rotation of the reflector assembly can adjust the direction in which the measurement light emitted by the signal transmission module 120 is reflected, thereby achieving 360° rotation measurement. At the same time, by setting the marker 140 and continuously measuring the marker 140, the error caused by temperature changes can be obtained in real time and compensated. The calibration of the marker 140 can effectively improve the measurement accuracy. Compared with complex temperature compensation algorithms, the calibration by setting the marker 140 is relatively simple in hardware and software implementation.

[0052] In an optional embodiment of the present application, there is one marker 140, and one marker 140 can be rotated synchronously with the reflector assembly, so that no matter what angle the reflector assembly is rotated to, the measuring light can always be irradiated onto the marker 140 and reflected back to the signal receiving module 130 by the marker 140, so that the marker 140 can be measured in real time for error compensation.

[0053] Specifically, the marker 140 has a real distance during the installation process. During actual use, a measured distance of the marker 140 is obtained through measurement. The correction coefficient is obtained by the ratio of the real distance to the measured distance. The product of the correction coefficient and the measured real-time distance of the object 500 is the distance of the object 500 after correction.

[0054] It is understandable that although the above-mentioned method of setting up the marker 140 that can rotate synchronously with the reflector assembly can solve the measurement accuracy problem to a certain extent, since the rotation installation position of the marker 140 cannot be very precise, other errors may be introduced, thereby causing inaccurate measurements.

[0055] Therefore, the present application also provides the following preferred solutions, referring to Figure 4 As shown, there are multiple markers 140, and the multiple markers 140 are evenly arranged around the periphery of the reflector assembly.

[0056] In this embodiment, multiple markers 140 are provided and distributed at different positions around the circumference of the reflector assembly, so that the reflector assembly can measure the distances of the multiple markers 140 during rotation, thereby obtaining a more accurate correction coefficient through calculation.

[0057] When multiple markers 140 are used, at least two of the markers 140 have different vertical distances from the rotation axis of the reflector assembly. By placing the markers 140 at different positions relative to the rotation axis, and calculating multiple correction coefficients based on the distances measured by different markers 140 and the actual distance, more accurate data can be obtained.

[0058] Specifically, when measuring at close range, the laser beam's divergence angle has little impact on measurement accuracy, but random errors such as electronic noise are relatively large. When measuring at long distances, factors such as the laser beam's divergence angle and atmospheric attenuation have a greater impact on measurement accuracy. By focusing on the direction in which the laser beam is most affected at different distances, a more accurate correction factor can be obtained.

[0059] By providing multiple markers 140, the systematic errors of the LiDAR at different distances can be more comprehensively reflected, thereby obtaining more accurate calibration coefficients. Furthermore, if the calibration coefficients of multiple markers 140 show regular differences, this may indicate that the LiDAR system has certain systematic errors, such as nonlinearity. Multiple markers 140 can reduce the impact of single marker failure or excessive error, thereby improving the reliability of the calibration results.

[0060] In this solution, by obtaining multiple correction coefficients, the method of finally obtaining the accurate correction coefficient can be:

[0061] Simple average: The arithmetic mean of the correction coefficients of all markers 140 is taken as the final correction coefficient.

[0062] Weighted average: The calibration coefficients are weighted averaged according to the measurement accuracy or importance of each marker 140 .

[0063] Curve fitting: The measured data and the true distances of all markers 140 are plotted as a scatter plot, and then curve fitting is performed to obtain a calibration curve.

[0064] Segmented correction: Divide the measurement range into multiple intervals and establish a correction model for each interval to adapt to the error changes in different distance segments.

[0065] It should be pointed out that the specific schemes of simple averaging, weighted averaging, curve fitting and segmented correction mentioned above are technical means commonly used by those skilled in the art and will not be described in detail in this application.

[0066] Preferably, the rotary ranging device described in the embodiment of the present application further includes a protective cover 110 disposed on the outside of the reflector assembly. The protective cover 110 not only provides physical protection by preventing foreign matter such as dust and water droplets from entering the interior of the laser radar, which could contaminate optical components or cause circuit short circuits, but also, through material selection and structural design, can play a certain role in temperature control, further mitigating the impact of ambient temperature changes on the laser radar. For example, heat dissipation fins are provided on the surface of the protective cover 110, which accelerate the heat dissipation of the protective cover 110 through the heat dissipation fins, thereby reducing the impact of temperature on the measurement accuracy of the rotary ranging device.

[0067] In this embodiment, the protective cover 110 is fixedly connected to the base 100 and is made of a transparent material. The marker 140 is a calibration coating applied on the protective cover 110 .

[0068] Optionally, as shown in the table below, in the embodiments of the present application, the coating thickness of the calibration coating is between 50-200 μm, the surface roughness Ra is less than 0.5 μm, and the side length or diameter of the coating block is between 5-20 mm.

[0069]

[0070]

[0071] It is understandable that the fact that the marker is a calibration coating applied on the protective cover does not limit the present application. In other embodiments, the marker may also be a calibration block fixed relative to the base.

[0072] Reference Figure 1As shown, in an optional embodiment of the present application, the reflector assembly has a transmitting signal reflection area 230 and a receiving signal reflection area 240, and the signal transmitting module 120 and the signal receiving module 130 are located on the same side of the reflector assembly and are not arranged on the same axis; the transmitting signal reflection area 230 is arranged corresponding to the signal transmitting module 120, and the receiving signal reflection area 240 and the signal receiving module 130 are both arranged around the rotation axis of the reflector assembly.

[0073] By arranging the signal transmitting module 120 and the signal receiving module 130 on the same side of the reflector assembly and making their optical paths non-overlapping, the signal transmitting module 120 and the signal receiving module 130 are avoided from being stacked, thereby reducing the cost of the convex lens.

[0074] Reference Figure 2 As shown, in another optional embodiment of the present application, the reflector assembly includes a first reflector lens 210 and a second reflector lens 220. The first reflector lens 210 and the second reflector lens 220 are arranged perpendicular to each other and are both located on the rotation axis of the reflector assembly. The size of the second reflector lens 220 is larger than that of the first reflector lens 210. The first reflector lens 210 and the second reflector lens partially overlap in the vertical direction. The area of the second reflector lens 220 corresponding to the first reflector lens 210 in the vertical direction is a hollow area 221. The second reflector lens 220 and the periphery of the hollow area 221 form a received signal reflection area 240.

[0075] Reference Figure 3 As shown, in another optional embodiment of the present application, the reflector assembly includes a semi-transparent mirror 250, which is configured to reflect a portion of the detection light and transmit a portion of the detection light. By providing the semi-transparent mirror 250 in the reflector assembly, the signal transmitting module 120 and the signal receiving module 130 can be arranged perpendicular to each other, avoiding the need for stacking the signal transmitting module 120 and the signal receiving module 130 without increasing the radial size of the reflector assembly, thereby saving costs.

[0076] The embodiment of the present application also includes a drive motor 300 and a rotary encoder for driving the reflector assembly to rotate. The power output shaft of the drive motor 300 is coaxially arranged with the rotation axis of the reflector assembly. The rotary encoder includes a code disk 410 and a magnet 420. The code disk 410 of the rotary encoder is fixedly set on the power output shaft of the drive motor 300, and the magnet 420 of the rotary encoder is fixedly set on the protective cover 110, or the code disk 410 of the rotary encoder is fixedly set on the protective cover 110, and the magnet 420 is fixedly set on the power output shaft of the drive motor 300.

[0077] The technical principles of the present application have been described above in conjunction with specific embodiments. These descriptions are intended solely to explain the principles of the present application and are not to be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, those skilled in the art will be able to devise other specific implementations of the present application without inventive effort, and such implementations will fall within the scope of protection of the present application.

Claims

1. A rotary distance measuring device, characterized in that: include: A base (100) on which a signal transmitting module (120) and a signal receiving module (130) are fixedly mounted; A reflector assembly rotatably disposed on the base (100); A marker (140) is provided on the periphery of the reflector assembly around the rotation axis of the reflector assembly. The marker (140) is configured to reflect the measurement light reflected by the reflector assembly back to the reflector assembly and then reflect it to a signal receiving module (130) via the reflector assembly.

2. The rotary distance measuring device according to claim 1, characterized in that: There are a plurality of markers (140), and the plurality of markers (140) are evenly arranged around the periphery of the reflector assembly.

3. The rotary distance measuring device according to claim 2, characterized in that: At least two of the markers (140) have different vertical distances from the axis of rotation of the reflector assembly.

4. The rotary distance measuring device according to claim 1, characterized in that: It also includes a protective cover (110) arranged outside the reflector assembly. The protective cover (110) is fixedly connected to the base (100) and is made of a transparent material.

5. The rotary distance measuring device according to any one of claims 1 to 4, characterized in that: The marker (140) is a calibration block fixed in position relative to the base (100).

6. The rotary distance measuring device according to claim 4, characterized in that: The marker (140) is a calibration coating applied on the protective cover (110).

7. The rotary distance measuring device according to claim 1, characterized in that: The reflector assembly comprises a transmission signal reflection area (230) and a reception signal reflection area (240); the signal transmission module (120) and the signal reception module (130) are located on the same side of the reflector assembly and are not coaxially arranged; The transmission signal reflection area (230) is arranged corresponding to the signal transmission module (120), and the reception signal reflection area (240) and the signal receiving module (130) are both arranged around the rotation axis of the reflector assembly.

8. The rotary distance measuring device according to claim 1, characterized in that: The reflector assembly comprises a first reflector lens (210) and a second reflector lens (220), wherein the first reflector lens (210) and the second reflector lens (220) are arranged perpendicular to each other and are both located on the rotation axis of the reflector assembly.

9. The rotary distance measuring device according to claim 8, characterized in that: The size of the second reflective lens (220) is larger than that of the first reflective lens (210); the first reflective lens (210) and the second reflective lens partially overlap in the vertical direction; the area corresponding to the second reflective lens (220) and the first reflective lens (210) in the vertical direction is a hollow area (221); and a receiving signal reflection area (240) is formed on the second reflective lens (220) and located around the hollow area (221).

10. The rotary distance measuring device according to claim 1, characterized in that: The reflector assembly comprises a semi-transparent and semi-reflective mirror (250), and the semi-transparent and semi-reflective mirror (250) is configured to reflect part of the detection light and transmit part of the detection light.

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