Laser radar

Abstract

The embodiment of the utility model relates to the technical field of laser detection, and discloses a laser radar. The laser radar comprises a shell module, a transceiving module, a scanning module and a calibration module. The transceiving module is used for emitting detection light to detect a target object and receiving echo light, and the echo light is formed by reflecting the detection light through the target object. The scanning module comprises a scanning element, the scanning element can rotate relative to the shell module, and the scanning element is used for receiving the detection light and deflecting the detection light so that the detection light can be emitted out of the laser radar. The calibration module comprises a reflector located in a detection field of view of the laser radar, and the reflector is used for reflecting the detection light emitted from the scanning element to form corresponding echo light. According to the laser radar, the current situation that the calibration process is tedious due to the fact that calibration components and calibration scenes outside the laser radar need to be relied on when the scanning angle of the scanning element is recalibrated by the laser radar in the related technology can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser detection, and in particular to a laser radar. BACKGROUND

[0002] The laser radar is a radar system for detecting the position, speed and other characteristic quantities of a target by emitting a laser beam. The working principle of the laser radar is to emit a detection light to a target object, receive a return light reflected from the target, and obtain relevant information of the target, such as target distance, direction, height, speed, attitude, and even shape, after appropriate processing.

[0003] Generally, the laser radar includes a shell, a transceiver module and a scanning module. The shell is a mounting base for the rest of the structures in the laser radar. The transceiver module is used to emit a detection light to detect a target object by the detection light, and to receive a return light formed by the detection light reflected by the target object. The scanning module includes a scanning element, such as a Micro-Electro-Mechanical System (MEMS) mirror, which is rotatable relative to the shell. The scanning element is used to receive and deflect the detection light emitted by the transceiver module, so as to change the emission direction of the detection light to form a specific detection field of view, thereby achieving detection of a target object in the detection field of view. Correspondingly, the scanning element is also used to receive and deflect the return light, so as to direct the return light to the transceiver module. SUMMARY

[0004] In related technologies, the laser radar uses an external calibration board and other elements to calibrate the angular position of the scanning element. For example, by placing the calibration board at different angular positions in the detection field of view of the laser radar, the relationship between the feedback signal (such as a feedback voltage signal) of the scanning element and the direction angle (such as the horizontal direction angle or the vertical pitch angle) of the calibration board relative to the laser radar is calibrated, and then the mapping relationship between the feedback signal of the scanning element and the direction angle of the detection light (i.e., the direction angle of the scanning element) can be obtained. However, as the working time increases, the feedback sensitivity of the scanning element will change, that is, the feedback signal amplitude under the condition of unit rotation angle of the scanning element will change. If the laser radar still determines the direction angle corresponding to the target object based on the mapping relationship calibrated before leaving the factory, the measured direction angle will have a large difference from the actual direction angle of the target object, which ultimately leads to a decrease in the control accuracy of the laser radar during the scanning process in the detection field of view.

[0005] For example, if the sensitivity of the vehicle-mounted laser radar changes, the vehicle needs to be driven to a preset calibration scene, or the laser radar needs to be taken out and placed in the above-mentioned calibration scene, and the angle position of the scanning element is re-calibrated. The process relies on external calibration components and calibration scenes, and the re-calibration process of the scanning angle of the scanning element is relatively cumbersome and high in cost.

[0006] The present application aims to provide a laser radar to improve the current situation that the laser radar in the related art needs to rely on external calibration components and calibration scenes for re-calibration of the scanning angle of the scanning element, thereby causing a cumbersome calibration process.

[0007] The embodiments of the present application solve the technical problems by adopting the following solutions:

[0008] The embodiments of the present application provide a laser radar, which comprises a shell module, a transceiver module, a scanning module and a calibration module. The transceiver module is housed in the shell module and is used for emitting probe light to detect a target object and receiving echo light formed by the probe light reflected by the target object. The scanning module is housed in the shell module and comprises a scanning element, which can rotate relative to the shell module and is used for receiving the probe light and deflecting the probe light so that the probe light is emitted out of the laser radar. The calibration module is installed on the shell module and comprises a mirror located in a detection field of view of the laser radar, which is used for reflecting the probe light emitted from the scanning element to form corresponding echo light.

[0009] In some embodiments, the calibration module further comprises a fixing part fixed to the shell module, and the fixing part comprises a reference area located in the detection field of view of the laser radar, and the mirror is fixed to the reference area, and the reflectivity of the reference area is lower than that of the mirror.

[0010] In some embodiments, the reference area comprises an area without the mirror, the reference area is a diffuse reflection structure, and the reflectivity of the reference area is lower than 50%.

[0011] In some embodiments, the mirror is configured such that the light path of the probe light emitted from the scanning module to the mirror is perpendicular to the mirror.

[0012] In some embodiments, the reference area is provided with a groove on the side facing the scanning module, and the mirror is arranged on the bottom surface of the groove.

[0013] In some embodiments, the reference region is provided with a fixing surface in the recess, the fixing surface is configured such that the optical path of the probe light emitted by the scanning module towards the recess is perpendicular to the fixing surface, and the mirror is fixed to the fixing surface; the fixing surface is provided with a second recess, and the mirror covers at least part of the second recess.

[0014] In some embodiments, the reference region is provided with a protrusion on the side facing the scanning module, and the mirror is arranged on the top surface of the protrusion.

[0015] In some embodiments, the mirror comprises a silver mirror or an aluminum mirror.

[0016] In some embodiments, the housing module comprises a base shell and a lens. The base shell defines a receiving cavity and is provided with a window communicating between the receiving cavity and the external environment. The lens comprises a lens barrel and a lens, the lens barrel is mounted at the window and is provided with a mounting hole extending in a first predetermined direction, the lens is mounted in the mounting hole, the lens blocks the window, and the calibration module is mounted on the lens barrel. Wherein, the mounting hole comprises a first cavity and a second cavity arranged in sequence along the first predetermined direction, the first cavity is closer to the scanning module than the second cavity, and the edge profile of the first cavity is within the edge profile of the second cavity when viewed along the first predetermined direction. The lens comprises two lenses, one of which is mounted in the first cavity and the other of which is mounted in the second cavity. The fixing part comprises a first part and a second part, the first part is arranged on the bottom wall of the second cavity, and the second part projects into the first cavity along the first predetermined direction. The second part comprises the reference region. One of the first part and the lens barrel is provided with a plurality of positioning columns, and the other is provided with a plurality of positioning holes, each positioning column corresponds to a positioning hole, and each positioning column projects into the corresponding positioning hole to realize the positioning of the fixing part and the lens barrel. The first part is provided with a first recess on the side facing the bottom wall of the second cavity, the first recess is used for accommodating glue, and the first part is bonded to the lens barrel by the glue.

[0017] In some embodiments, the laser radar comprises two calibration modules, and along a second predetermined direction, the two calibration modules are arranged on both sides of the axis of the lens, the second predetermined direction is perpendicular to the first predetermined direction and the thickness direction of the laser radar; the scanning element comprises a two-dimensional galvanometer, and the mirrors of the two calibration modules are staggered along the thickness direction.

[0018] Compared with the laser radar in the related art, the laser radar provided in the embodiments of the present application can determine the scanning angle change caused by the change of the feedback sensitivity of the scanning element based on the built-in calibration module without the aid of the calibration element outside the laser radar and without the need to separately configure the corresponding calibration scene for the laser radar, so that the calibration process is simpler. That is, the laser radar provided in the embodiments of the present application can improve the status that the laser radar in the related art needs to rely on the calibration components and calibration scenes outside the laser radar when recalibrating the angle scanned by the scanning element, and thus the calibration process is complicated. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0020] Figure 1 is a perspective view of the laser radar provided in some embodiments of the present application;

[0021] Figure 2 is Figure 1 is an exploded view of the laser radar in the embodiment;

[0022] Figure 3 is Figure 1 is a perspective view of the lens in the embodiment;

[0023] Figure 4 is Figure 3 is a cut view of the lens along the A-A line in the embodiment;

[0024] Figure 5 is Figure 4 is a perspective view of the calibration module in the embodiment;

[0025] Figure 6 is a perspective view of the calibration module provided in another embodiment of the present application;

[0026] Figure 7 is Figure 6 is a partial enlarged view at B in the embodiment.

[0027] Explanation of reference signs:

[0028] 1, laser radar;

[0029] 100, housing module; 110, base housing; 120, lens; 111, bottom housing; 112, top housing; 1111, bottom wall; 1112, first side wall; 1113, second side wall; 1114, third side wall; 1121, top wall; 1122, fourth side wall; 1123, fifth side wall; 1124, sixth side wall; 121, lens barrel; 122, lens; 1211, mounting hole; 1212, first cavity; 1213, second cavity; 1221, first lens; 1222, second lens; 101, receiving cavity; 102, window;

[0030] 200, transceiver module;

[0031] 300, scanning module;

[0032] 400, calibration module; 410, fixed part; 420, mirror; 411, first part; 412, second part; 4111, positioning hole; 4112, first recess; 4121, reference area; 4122, boss;

[0033] 400b, calibration module; 410b, fixed part; 420b, mirror; 4121b, reference area; 4123b, groove; 4124b, fixed surface; 4125b, second recess. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the present application clearer, the following will further describe the embodiments of the present application with reference to the accompanying drawings.

[0035] The following description refers to the accompanying drawings. Unless otherwise noted, like elements in different drawings represent the same or similar elements. The following exemplary embodiments are described in terms of specific embodiments by way of example only. Descriptions of these embodiments in terms of an apparatus and methods consistent with the present application do not limit the scope of the present application to only these specific embodiments.

[0036] In the related art, a laser radar uses an external calibration board and the like to calibrate the angle position scanned by a scanning element; for example, by placing the calibration board at different angle positions within the detection field of view of the laser radar, the relationship between the feedback signal (e.g. feedback voltage signal) of the scanning element and the direction angle (e.g. horizontal azimuth angle or vertical pitch angle) of the calibration board relative to the laser radar is calibrated, and then the mapping relationship between the feedback signal of the scanning element and the direction angle of the detected light (i.e. the direction angle of the scanning element) can be obtained. However, as the working time increases, the feedback sensitivity of the scanning element will change, i.e. the feedback signal amplitude under the condition of unit rotation angle of the scanning element will change; if the laser radar still determines the direction angle corresponding to the target object based on the mapping relationship calibrated before leaving the factory, the measured direction angle will have a large difference from the actual direction angle of the target object, and finally the control accuracy of the laser radar in the scanning process within the detection field of view will decrease.

[0037] Taking a vehicle-mounted laser radar as an example, if the sensitivity of the laser radar changes, the car needs to be driven to a preset calibration scene, or the laser radar needs to be taken out separately and placed in the above-mentioned calibration scene, and the angle position scanned by the scanning element needs to be re-calibrated. This process relies on external calibration components and calibration scenes, and the re-calibration process of the scanning angle of the scanning element is relatively cumbersome and costly.

[0038] Therefore, the embodiments of the present application provide a laser radar to improve the situation that the laser radar in the related art needs to rely on external calibration components and calibration scenes when recalibrating the angle scanned by the scanning element, and thus the calibration process is cumbersome.

[0039] Please refer to Figure 1 and Figure 2 which respectively show the perspective view and exploded view of a laser radar 1 provided by some embodiments of the present application, which includes a housing module 100, a transceiver module 200, a scanning module 300 and a calibration module 400. Figure 5 The transceiver module 200 is housed in the housing module 100, which is used to emit detection light to detect a target object and receive return light; wherein the return light is formed by the reflection of the detection light on the target object. The scanning module 300 is housed in the housing module 100, which includes a scanning element that can rotate relative to the housing module 100; the scanning element is used to receive and deflect the detection light so that the detection light is emitted out of the laser radar 1. The calibration module is installed on the housing module 100, which includes a mirror 420 located in the detection field of view of the laser radar 1, which is used to reflect the detection light emitted from the scanning element to form corresponding return light.

[0040] It should be noted that the "target object" described in the present application refers to the detection object of the lidar, including but not limited to: vehicles, pedestrians, buildings, vegetation and the ground; the "detection light" described in the present application refers to the laser beam emitted by the lidar for detecting the above target object; the "echo light" described in the present application refers to the laser beam formed by the target object reflecting the above detection light and directed towards the lidar. The target object can be an object other than the lidar, such as the above vehicles, pedestrians, etc., or the above calibration module 400 integrated inside the lidar 1. Next, the specific structure of the lidar 1 will be described in detail in combination with the drawings.

[0041] For the above-mentioned housing module 100, please refer to Figure 1 And Figure 2 It is the mounting base of the remaining components in the lidar 1, and also constitutes the protection structure of the remaining components in the lidar 1. In the present embodiment, the housing module 100 includes a base shell 110 and a lens 120. Among them, the base shell 110 is the main part of the housing module 100, which defines a receiving cavity 101 for accommodating the above-mentioned transceiver module 200 and scanning module 300; the base shell 110 is also provided with a window 102 communicating between the receiving cavity 101 and the external environment of the lidar 1, for the above-mentioned detection light and echo light to enter and exit the lidar 1. The lens 120 is arranged at the window 102, which is used for optical processing of the detection light and echo light, and at the same time, the lens 120 blocks the above-mentioned window 102, thereby realizing the sealing of the base shell 110.

[0042] For the foregoing base shell 110, please continue to refer to Figure 2The base shell 110 includes a bottom shell 111 and a top shell 112 which are butted and fixed along a thickness direction Z of the lidar 1 to define the above-mentioned receiving cavity 101. In the present application, the "thickness direction" refers to a direction determined based on a bottom and a top of the lidar 1 when the lidar 1 is installed on a movable device (e.g., a vehicle), wherein the end close to the mounting surface of the movable device is the bottom, the end away from the mounting surface is the top, and the thickness direction is determined based on the bottom and the top, such as the direction determined based on one of the bottom and the top pointing to the other. The bottom shell 111 includes a bottom wall 1111, a first side wall 1112, a second side wall 1113, and a third side wall 1114. The bottom wall 1111 is substantially flat and plate-shaped, and the first side wall 1112 is disposed at one end of the bottom wall 1111 along a first preset direction X. The first preset direction X is perpendicular to the above-mentioned thickness direction Z. One end of the second side wall 1113 is connected to the first side wall 1112, and the other end extends away from the first side wall 1112 along the first preset direction X. The height of the first side wall 1112 compared to the bottom wall 1111 is smaller at a position farther away from the first side wall 1112. One end of the third side wall 1114 is connected to the first side wall 1112, and the other end also extends away from the first side wall 1112 along the first preset direction X. The height of the first side wall 1112 compared to the bottom wall 1111 is smaller at a position farther away from the first side wall 1112. The third side wall 1114 and the second side wall 1113 are oppositely disposed along a second preset direction Y. The second preset direction Y is perpendicular to the above-mentioned thickness direction Z and the first preset direction X. The bottom shell 111 does not have a side wall on the side away from the first side wall 1112, thereby forming an opening on that side to facilitate assembly of the above-mentioned transceiver module 200, scanning module 300, circuit board, and other components.

[0043] The top shell 112 comprises a top wall 1121, a fourth side wall 1122, a fifth side wall 1123, and a sixth side wall 1124. The top wall 1121 is also substantially in the form of a flat plate, which is oppositely arranged to the bottom wall 1111 along the thickness direction Z. Along the first preset direction X, the fourth side wall 1122 is arranged at one end of the top wall 1121 away from the first side wall 1112, and the fourth side wall 1122 is oppositely arranged to the first side wall 1112 along the first preset direction X. The fourth side wall 1122 fills the opening area of the bottom shell 111 to seal the area. One end of the fifth side wall 1123 is connected to the fourth side wall 1122, and the other end extends away from the fourth side wall 1122 along the first preset direction X, and the height of the fifth side wall 1123 compared to the height of the top wall 1121 is smaller at a position farther away from the fourth side wall 1122. The fifth side wall 1123 and the second side wall 1113 are complementary fitting structures, and the fifth side wall 1123 and the second side wall 1113 jointly splice a side wall of the base shell 110 between the first side wall 1112 and the fourth side wall 1122. One end of the sixth side wall 1124 is connected to the fourth side wall 1122, and the other end also extends away from the fourth side wall 1122 along the first preset direction X, and the height of the sixth side wall 1124 compared to the height of the top wall 1121 is smaller at a position farther away from the fourth side wall 1122. The sixth side wall 1124 is oppositely arranged to the fifth side wall 1123 along the second preset direction Y, and the sixth side wall 1124 and the third side wall 1114 are complementary fitting structures, and the sixth side wall 1124 and the third side wall 1114 jointly splice another side wall of the base shell 110 between the first side wall 1112 and the fourth side wall 1122. The top shell 112 does not have a side wall on the side away from the fourth side wall 1122, thereby forming an opening on that side; the first side wall 1112 fills the opening to seal the opening. It should be noted that the "second preset direction" in the present application is perpendicular to the first preset direction X; for example, in the present embodiment, the second preset direction Y is a horizontal direction perpendicular to the thickness direction Z and the first preset direction X, of course, in other embodiments, the second preset direction Y can be appropriately changed on this basis, and the present application does not limit it.

[0044] The bottom shell 111 and the top shell 112 are spliced along the thickness direction Z to jointly define the accommodation cavity 101. The bottom shell 111 is provided with the window 102 at the first side wall 1112, and the window 102 penetrates the first side wall 1112, thereby communicating the accommodation cavity 101 with the external environment of the laser radar 1.

[0045] Regarding the foregoing lens 120, please refer to Figure 3 and Figure 4respectively show a perspective view and a cross-sectional view along the line A-A of the lens 120, which includes a lens barrel 121 and a lens 122. The lens barrel 121 is mounted at the window 102, is spaced apart from the scanning module 300 along the first preset direction X, and is provided with a mounting hole 1211 extending along the first preset direction X. The lens 122 is mounted in the mounting hole 1211. The lens 120 seals the window 102 as a whole, so that the shell module 100 forms a structure sealed to the outside. In the embodiment, the mounting hole 1211 includes a first cavity 1212 and a second cavity 1213 arranged in sequence along the first preset direction X. The first cavity 1212 is a cavity close to the accommodation cavity 101, one end of which is located in the accommodation cavity 101 and communicates with the accommodation cavity 101, and the other end extends towards or passes through the window 102. The second cavity 1213 is a cavity away from the accommodation cavity 101, one end of which communicates with the first cavity 1212, and the other end is located outside the base shell 110; when viewed along the first preset direction X, the edge profile of the first cavity 1212 is located within the edge profile of the second cavity 1213, that is, the second cavity 1213 is a larger cavity. The lens 120 includes two lenses 122, which are a first lens 1221 and a second lens 1222 respectively; wherein the first lens 1221 is mounted in the first cavity 1212, and the second lens 1222 is mounted in the second cavity 1213. The detection light generated by the transceiver module 200 passes through the first lens 1221 and the second lens 1222 in sequence after being deflected by the scanning module to exit to the outside of the laser radar 1, and then detect the surrounding environment; that is, the second lens 1222 also constitutes a window sheet of the laser radar 1.

[0046] For the transceiver module 200, please refer to Figure 2The transceiver module 200 is accommodated in the accommodation cavity 101 and is mounted on the housing module 100, for example, the transceiver module 200 can be fixed to the bottom wall 1111. The transceiver module 200 includes a transmitting module and a receiving module. The transmitting module is used to generate probe light for detecting a target object. The transmitting module includes at least one laser, for example, in some embodiments, the transmitting module includes one laser; for another example, in some other embodiments, the transmitting module includes two or more lasers arranged according to a preset rule. The receiving module is used to receive echo light formed by reflecting the probe light on the target object, and to perform photoelectric conversion to obtain corresponding electrical signals, so that the signal processing module of the laser radar 1 can process the electrical signals to obtain information such as the distance, speed and reflectivity of the target object relative to the laser radar 1. In some embodiments, the receiving module can include a silicon photomultiplier, which has a high dynamic range and can detect weak echo light signals; of course, in other embodiments of the present application, the receiving module can also include other types of photodetectors as long as it can receive echo light and complete photoelectric conversion.

[0047] For the above-mentioned scanning module 300, please continue to refer to Figure 2The scanning module 300 is configured to scan the probe light emitted by the transceiver module 200, so that the probe light can form a specific probe field of view. In the embodiment, the scanning module 300 comprises a scanning element (not shown in the figure), which is configured to receive the probe light and deflect it so that the probe light is emitted outside the laser radar. The scanning element can rotate relative to the housing module 100, so that the direction of the probe light changes after being reflected, thereby realizing the above-mentioned probe field of view. Optionally, the scanning element can comprise a two-dimensional galvanometer, such as a two-dimensional MEMS (Micro-Electro-Mechanical System) galvanometer, to realize two-dimensional scanning. For example, in the embodiment, the two-dimensional galvanometer can rotate about a first rotation axis parallel to the above-mentioned thickness direction Z to realize the yaw motion along the above-mentioned second preset direction Y; the two-dimensional galvanometer can also rotate about a second rotation axis parallel to the second preset direction Y to realize the yaw motion along the thickness direction Z. Of course, in other embodiments of the application, the scanning element can also comprise other types of scanning devices; for example, in some other embodiments, the scanning element can be a combination of a one-dimensional galvanometer and a multi-faceted mirror; for example, in some other embodiments, the emission module can comprise a linear array of multiple lasers, and the scanning element comprises a one-dimensional mirror; here, it is not limited one by one, as long as the scanning module 300 can complete the scanning of the probe light, and preferably, the above-mentioned two-dimensional scanning scheme can be used. In addition, the scanning module 300 further comprises a scanning driving module connected with the scanning element, which is configured to drive the scanning element to rotate. In the embodiment, the driving module comprises a coil and a magnet. Specifically, the coil is integrated in the above-mentioned two-dimensional galvanometer; the magnet is arranged adjacent to the two-dimensional galvanometer, and the two-dimensional galvanometer is in the magnetic field formed by the magnet; when the coil is energized according to a preset rule, it will rotate under the action of the magnetic field.

[0048] In order to obtain the current scanning direction angle of the two-dimensional galvanometer, the two-dimensional galvanometer can be integrated with a sensor for detecting the direction angle, such as a piezoresistive sensor. Because the feedback voltage signal output by the piezoresistive sensor is different when the two-dimensional galvanometer scans different direction angles, the mapping relationship between the two can be established through the calibration process mentioned above; in this way, during the working process of the laser radar after it is manufactured, the current scanning direction angle of the two-dimensional galvanometer can be determined through the feedback voltage signal output by the piezoresistive sensor.

[0049] However, as the working time increases, the feedback sensitivity of the scanning element will change, that is, the amplitude of the feedback signal (such as the feedback voltage signal mentioned above) under the condition of unit rotation angle of the scanning element will change; if the laser radar still determines the corresponding direction angle of the target object based on the mapping relationship calibrated before leaving the factory, there will be a large difference between the measured direction angle and the actual direction angle of the target object, and finally the control accuracy of the laser radar in the scanning process in the detection field will decrease. To overcome this deficiency, the laser radar 1 provided in the embodiments of the present application further includes a calibration module 400, which provides a structural basis for the secondary calibration of the scanning element, thereby facilitating the improvement of the current situation of the complicated secondary calibration process of the laser radar in the related art.

[0050] For the calibration module 400, please refer to Figure 5 which shows a perspective view of the calibration module 400, and in combination with Figures 1 to 4 , the calibration module 400 is installed in the shell module 100 and includes a mirror 420 located in the detection field of view of the laser radar 1. The mirror 420 is used to reflect the detection light reflected by the scanning module 300 towards the mirror 420 to form corresponding echo light, so as to determine the angular position of the mirror 420 in the detection field of view by the laser radar 1. Considering that the above-mentioned lens 120 is actually designed and selected based on the detection field of view requirement of the laser radar 1, in the present embodiment, the calibration module 400 is installed on the above-mentioned lens 120, which can more easily ensure that the mirror 420 is located in the detection field of view of the laser radar 1, and the following will be described taking this setting mode as an example; but it should be understood that in other embodiments of the present application, the calibration module 400 can also be installed on the base shell 110, as long as it has the above-mentioned mirror located in the detection field of view of the laser radar 1.

[0051] Specifically, the calibration module 400 includes a fixed part 410 and the above-mentioned mirror 420. Wherein, the fixed part 410 is installed on the bottom wall of the second cavity 1213, which includes a first part 411 located on the bottom wall of the second cavity 1213 and a second part 412 located outside the bottom wall of the second cavity 1213; one end of the second part 412 is connected with the first part 411, and the other end extends to the opposite side of the first cavity 1212. More specifically, when the fixed part 410 is projected along the above-mentioned first preset direction X, the first part 411 is located on the bottom wall of the second cavity 1213, and the end of the second part 412 away from the first part 411 is located in the first cavity 1212. The second part 412 includes a reference area 4121 located in the detection field of view of the laser radar 1, which is used to fix the above-mentioned mirror 420, thereby effectively ensuring that the mirror 420 is also located in the detection field of view of the laser radar 1.

[0052] As for the fixing manner of the fixing portion 410, it is actually various. For example, in some embodiments, the fixing portion 410 and the lens barrel 121 can be fixed by bonding. Specifically, the first portion 411 is substantially a rectangular plate structure, which is provided with a plurality of positioning holes 4111; the bottom wall of the second cavity 1213 is provided with a plurality of positioning columns (not shown in the figure), each positioning column corresponds to a positioning hole 4111, thereby realizing the positioning of the fixing portion 410 and the lens barrel 121. Preferably, the positioning holes 4111 and the positioning columns can be provided with two respectively, wherein one positioning hole 4111 is a circular hole, and the other positioning hole 4111 is a waist-shaped hole; wherein the width of the waist-shaped hole is equal to the diameter of the positioning column, and the length of the waist-shaped hole is greater than the diameter of the positioning column. The positioning column cooperates with the circular positioning hole 4111, and the other positioning column cooperates with the waist-shaped positioning hole 4111, and the setting of the waist-shaped hole can provide a certain redundancy to avoid that it cannot normally cooperate with the corresponding positioning column. The side of the first portion 411 facing the bottom wall of the second cavity 1213 is provided with a first sink groove 4112, which can be used to accommodate glue. Before the fixing portion 410 is assembled to the lens barrel 121, the first sink groove 4112 can be glued first; then, the fixing portion 410 is positioned and installed to the bottom wall of the second cavity 1213 based on the positioning hole 4111 and the positioning column; after that, the position and attitude of the fixing portion 410 are adjusted to the desired state, and the fixing of the fixing portion 410 can be completed after waiting for the glue to solidify.

[0053] Preferably, the reference area 4121 includes an area provided with the mirror 420 (corresponding to the black area shown below) and an area not provided with the mirror 420 (corresponding to the white area shown below). Figure 5 Preferably, the reference area 4121 includes an area provided with the mirror 420 (corresponding to the black area shown below) and an area not provided with the mirror 420 (corresponding to the white area shown below). Figure 5The reflectivity of the reference region 4121 is lower than the reflectivity of the mirror 420. This configuration is conducive to constructing the neighborhood of the mirror 420 as a low-reflectivity reference region 4121, which can shield other target objects in the field of view region and avoid the influence of other target objects in the field of view region on the detection of the mirror 420, thereby building a relatively pure detection environment for the mirror 420; and the mirror 420 is located in the region as a higher-reflectivity object and has a reflectivity difference with the reference region 4121. In this way, the laser radar 1 can more easily identify the mirror 420 when acquiring point cloud data. In some applications, the reference region can be a diffuse reflection structure, which generally has a low reflectivity and thus has a significant reflectivity difference with the mirror; after the laser radar generates the point cloud data, the corresponding data points of the reference region and the mirror can be more easily determined in the point cloud data. For example, the reflectivity of the reference region can be less than 50%; in this way, the mirror 420 and the reference region 4121 of the fixed part 410 will have a significant reflectivity difference, which is conducive to better distinguishing the outline of the mirror 420. For example, in some embodiments, the reflectivity of the reference region can be less than 30%, such as 25%, 20%, 10%, 5%, etc. It should be noted that the "reflectivity" described in the present application is a parameter commonly used in the field of laser radar detection to characterize the reflection capability. Generally, the surface reflectivity of a Kodak white board (calibration white board) is defined as 100%, and the reflectivity of other objects can be scaled based on this.

[0054] As for the material composition of the mirror 420, it is actually diverse, which can be a silver mirror or an aluminum mirror, or a non-light-transmitting mirror made of other materials, such as a mirror made of a semiconductor medium such as silicon, which is not limited by the present application.

[0055] It should be noted that the reflection direction of specular reflection can be considered as single, unlike diffuse reflection which forms reflected echo light in all directions. At this time, the angle of the plane in which the mirror 420 is located is very important. Specifically, the mirror needs to be configured such that the optical path of the detection light emitted from the scanning module 300 to the mirror 420 is perpendicular to the mirror; in this way, the reflected echo light formed by the mirror 420 can return along the original optical path and be received by the transceiver module 200, thereby forming corresponding point cloud.

[0056] For example, please continue to refer to Figure 5In some applications, the reference region 4121 is provided with a protrusion 4122 on the side facing the scanning module 300, and the mirror is arranged on the top surface of the protrusion 4122. The top surface is configured such that the probe light emitted from the scanning module 300 towards the protrusion 4122 is perpendicular to the top surface of the protrusion 4122. In this way, the probe light will be perpendicular to the mirror and return to the transceiver module 200 along the original light path.

[0057] For example, please refer to Figures 6 to 7 which respectively show the schematic diagram of the calibration module 400b in some other applications of the present application and Figure 6 the partial enlarged schematic diagram of B in FIG. 4B. The calibration module 400bb is basically the same as the calibration module 400 in the above embodiment, and the main difference between them is that the fixed part 410b includes a reference region 4121b within the detection field of view of the laser radar, and the reference region 4121b is provided with a groove 4123b; and the mirror 420b is installed in the groove 4123b.

[0058] Optionally, the inside of the groove 4123b is provided with a fixing surface 4124b, which is arranged obliquely relative to the first preset direction X and is configured such that the light path of the probe light emitted from the scanning module 300 towards the groove 4123b is perpendicular to the fixing surface 4124b; and the mirror 420b is installed on the fixing surface 4124b. In this way, when the probe light is incident on the mirror 420b, the echo light formed thereby will return along a far light path and be received by the transceiver module 200. In this embodiment, the mirror 420b is fixed in the groove 4123b by means of point gluing. Specifically, the fixed part 410b is provided with a second groove 4125b on the fixing surface 4124b, which divides the fixing surface 4124b into multiple regions; for example, the fixing surface 4124b can be provided with two second grooves 4125b, which are perpendicular to each other and thereby divide the fixing surface 4124b into four regions. The mirror is carried on the multiple regions and is fixed to the fixed part by means of gluing, covering at least part of the second groove 4125b. When the mirror 420b is fixed, it can be point-glued on the back surface (the surface facing the fixing surface 4124b) and placed in the correct position on the fixing surface 4124b, and then the glue is cured. The second groove 4125b can be used to accommodate excess glue to prevent glue overflow.

[0059] Preferably, to facilitate better reference surface when forming the top surface of the boss 4122 or the bottom surface of the groove 4123b, the reference area 4121 can be provided with an inclined surface inclined relative to the first preset direction X on the side facing the scanning module 300, and the light path of the probe light emitted from the scanning module 300 to the boss or the groove is perpendicular to the inclined surface. When forming the top surface of the boss 4122 or the bottom surface of the groove, it is only necessary to control the top surface of the boss 4122 or the bottom surface / guide surface 4124b of the groove 4123b to be parallel to the inclined surface.

[0060] It is worth supplementing that, since the calibration module 400 is used to calibrate the direction angle of the scanning element, it is necessary to ensure that the position and attitude of the calibration module 400 do not change substantially during the service life of the laser radar 1. In the embodiments of the present application, if the fixed part is formed separately from the lens barrel, the strength of the fixed part itself should be higher than a preset strength threshold, and the rigidity should be higher than a preset rigidity threshold. The preset strength threshold and the preset rigidity threshold can be determined by testing or simulation based on the working conditions of the laser radar 1. For example, the fixed part can be formed of the same material as the lens barrel. In addition, when the fixed part is fixed to the lens barrel, a hard glue can be used to ensure the reliability of the connection, and of course a threaded fastener can also be used for fixation. If the fixed part is integrally formed with the lens barrel, in general, the strength of the fixed part itself can be better guaranteed, and of course the material of the lens barrel can be appropriately selected to improve the reliability of the structure of the fixed part. As for the setting mode of the reflector, if the reflector is formed on the surface of the fixed part, its position and attitude relative to the fixed part are relatively stable, and only the position and attitude of the fixed part need to be better durable. If the reflector is formed separately from the fixed part and fixed to the fixed part, a hard glue should be used to avoid changes in the position and attitude of the reflector due to the failure of the glue.

[0061] The structures of the shell module 100, the transceiver module 200, the scanning module 300 and the calibration module 400 are described above in turn, and the working principle of the laser radar 1 based on the calibration module 400 to achieve calibration will be briefly described below.

[0062] When the laser radar is completed after calibration, the direction angle corresponding to the reflector 420 can be obtained by scanning. For convenience of description, this direction angle is referred to as a first preset direction angle. When the feedback sensitivity of the scanning element changes after the laser radar is used for a long time, the direction angle corresponding to the reflector 420 can be obtained by scanning. For convenience of description, this direction angle is referred to as a second preset direction angle. In this way, the proportion of the change in the feedback sensitivity of the scanning element can be determined based on the first preset direction angle and the second preset direction angle, and the direction angle determined based on the feedback signal can be compensated based on the proportion to obtain a corrected direction angle.

[0063] Considering that the direction angle of the scanning element scanning is determined by the feedback signal output by the sensor (such as a piezoresistive sensor) integrated in the scanning element, and because the sensitivity of the sensor at different positions may vary, the feedback sensitivity change on both sides of the central angle position of the scanning element in the second preset direction may not be consistent. To further improve this deficiency, in the embodiment, the laser radar 1 includes two calibration modules 400, which are arranged on both sides of the axis of the lens 120 along the second preset direction Y.

[0064] Based on this, in some applications, the change ratio of the feedback sensitivity on one side of the optical axis of the lens 120 can be determined by the calibration module 400 located on the side, and then the first compensation coefficient corresponding to the side can be determined, the change ratio of the feedback sensitivity on the other side of the optical axis of the lens 120 can be determined by the calibration module 400 located on the side, and then the second compensation coefficient corresponding to the side can be determined; then, based on the first compensation coefficient and the second compensation coefficient, the direction angle compensation is performed on the point cloud points with the direction angle located on the same side in the point cloud data. This application mode can use different compensation methods for compensation on both specific position sides when the scanning element scans in the second preset direction, which is beneficial to improving the accuracy of the compensation process to a certain extent. In other applications, the first included angle corresponding to the mirrors 420 of the two calibration modules 400 in the detection field of view of the laser radar 1 can be determined when the laser radar is shipped, and the first included angle can be determined according to the direction angle corresponding to the mirror 420 of one calibration module 400 and the direction angle corresponding to the mirror 420 of the other calibration module 400 when the laser radar 1 is shipped; for example Figure 4 The direction angle corresponding to the mirror 420 of the calibration module 400 on the right side (corresponding to the left side of the field of view of the laser radar 1) is -55°, and the direction angle corresponding to the mirror 420 of the calibration module 400 on the left side (corresponding to the right side of the field of view of the laser radar 1) is 55°, and the first included angle is 110°. Then determine the second included angle corresponding to the mirrors 420 of the two calibration modules 400 in the detection field of view of the laser radar 1, and the second included angle can be determined according to the direction angle corresponding to the mirror 420 of one calibration module 400 and the direction angle corresponding to the mirror 420 of the other calibration module 400 at present; for example Figure 4The direction angle corresponding to the mirror of the calibration module on the right side (corresponding to the left side of the field of view of the lidar 1) is -57°, and the direction angle corresponding to the mirror of the calibration module on the left side (corresponding to the right side of the field of view of the lidar 1) is 58°, and the second preset direction angle is 115°. Then, the compensation coefficient is determined according to the second included angle and the first included angle; specifically, the ratio of the first included angle to the second included angle can be determined as the compensation coefficient; for example, based on the above example, the compensation coefficient α = 110° / 115° = 0.9565 can be determined. After that, when the lidar 1 detects and obtains the point cloud data, the direction angle of the point cloud point in the point cloud data is multiplied by the above compensation coefficient. The application mode uses the included angle corresponding to the two calibration modules 400 to determine the compensation coefficient, which can balance the unilateral error introduced by the unilateral calibration module 400 when detecting the direction angle, and is helpful to improve the accuracy of the compensation process.

[0065] It is worth mentioning that the mirrors 420 of the two calibration modules 400 are staggered along the thickness direction Z, and the ratio of the distance by which the two mirrors 420 are staggered along the second preset direction Y to the distance by which the two mirrors 420 are staggered along the thickness direction Z is equal to a first ratio; wherein the first ratio is the ratio of the angular velocity of the scanning element by which the scanning element is deflected along the second preset direction Y to the angular velocity of the scanning element by which the scanning element is deflected along the thickness direction Z. Since the scanning element is a two-dimensional galvanometer, it rotates relative to the housing around the first rotation axis and the second rotation axis, that is, it deflects along the second preset direction Y to realize horizontal scanning of the detection light, and at the same time, it also deflects along the thickness direction Z, so that the detection light is scanned in the vertical direction; therefore, the above arrangement is helpful to make the detection light pass through the mirrors 420 of the two calibration modules in turn in the same period of horizontal scanning of the scanning element, so as to obtain corresponding point cloud data.

[0066] In summary, the lidar 1 provided by the embodiments of the present application includes a housing module 100, a transceiver module 200, a scanning module 300 and a calibration module 400. The calibration module 400 includes a mirror located in the detection field of view of the lidar 1.

[0067] Compared with the prior art, the laser radar 1 provided in the embodiments of the present application can determine the change of the scanning angle caused by the change of the feedback sensitivity of the scanning element based on the built-in calibration module 400 without the aid of calibration elements other than the laser radar 1 and without the need to separately configure a corresponding calibration scene for the laser radar 1, and therefore the calibration process is simpler. That is, the laser radar 1 provided in the embodiments of the present application can improve the status of the prior art that the laser radar needs to rely on calibration components and calibration scenes outside the laser radar to recalibrate the angle scanned by the scanning element, and therefore the calibration process is complicated.

[0068] In the description of the present application, it should be understood that the terms "first", "second" and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, "a plurality of" means at least two, for example, two, three, four, and the like, unless otherwise specified. "And / or" describes the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the following three cases: A exists alone, A and B exist together, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0069] The above disclosure is only the preferred embodiments of the present application, and of course cannot limit the scope of the rights of the present application, so equivalent changes made according to the claims of the present application still fall within the scope of the present application.

Claims

1. A lidar, comprising: The application relates to a laser radar, which comprises a housing module, a transceiver module, a scanning module and a calibration module. The transceiver module is accommodated in the housing module and is used for emitting probe light to detect a target object and receiving echo light formed by the probe light reflected by the target object. The scanning module is accommodated in the housing module and comprises a scanning element which can rotate relative to the housing module and is used for receiving the probe light and deflecting the probe light so that the probe light is emitted out of the laser radar. The calibration module is installed on the housing module and comprises a mirror located in a detection field of view of the laser radar, the mirror is used for reflecting the probe light emitted from the scanning element to form corresponding echo light. The calibration module further comprises a fixing part fixed to the housing module, the fixing part comprises a reference area located in the detection field of view of the laser radar, and the mirror is fixed to the reference area. The reference area has a reflectivity lower than that of the mirror.

2. The lidar of claim 1, wherein, The reference area is a region without the mirror and has a diffuse reflection structure, and the reflectivity of the reference area is lower than 50%.

3. The lidar of claim 2, wherein, The mirror is configured such that the light path of the probe light emitted from the scanning module to the mirror is perpendicular to the mirror.

4. The lidar of claim 2, wherein, The reference area is provided with a groove on the side facing the scanning module, and the mirror is arranged in the groove.

5. The lidar of claim 4, wherein, The reference area is provided with a fixing surface in the groove, the fixing surface is configured such that the light path of the probe light emitted from the scanning module to the groove is perpendicular to the fixing surface, and the mirror is fixed to the fixing surface.

6. The lidar of claim 5, wherein, The fixing surface is provided with a second sink, and the mirror covers at least part of the second sink. The reference area is provided with a boss on the side facing the scanning module, and the mirror is arranged on the top surface of the boss.

7. The lidar of claim 5, wherein, The mirror comprises a silver mirror or an aluminum mirror.

8. The lidar of claim 1, wherein, The housing module comprises a base shell defining an accommodation cavity and provided with a window communicating with the accommodation cavity and an external environment, and a lens barrel installed at the window and provided with a mounting hole extending along a first preset direction.

9. The lidar of claim 2, wherein, The lens barrel is provided with a lens installed in the mounting hole, and the lens barrel seals the window. The calibration module is installed in the lens barrel. The mounting hole comprises a first cavity and a second cavity arranged in sequence along the first preset direction. The first cavity is closer to the scanning module than the second cavity. The edge profile of the first cavity is located within the edge profile of the second cavity when viewed along the first preset direction. The lens comprises two lenses, one of which is installed in the first cavity, and the other of which is installed in the second cavity. The fixing part comprises a first part and a second part. The first part is arranged on the bottom wall of the second cavity and projects along the first preset direction. The second part extends into the first cavity and comprises the reference area. One of the first part and the lens barrel is provided with a plurality of positioning columns, and the other is provided with a plurality of positioning holes. Each positioning column corresponds to a positioning hole, and each positioning column extends into the corresponding positioning hole to realize positioning of the fixing part and the lens barrel. The first part is provided with a first groove on one side facing the bottom wall of the second cavity, the first groove is used for accommodating glue, and the first part is bonded to the lens barrel through the glue.

10. The lidar of claim 9, wherein, The laser radar comprises two calibration modules, and the two calibration modules are arranged on two sides of the axis of the lens along a second preset direction, the second preset direction is perpendicular to the first preset direction and a thickness direction of the laser radar. The scanning element comprises a two-dimensional galvanometer, and the mirrors of the two calibration modules are staggered along the thickness direction.

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