Scanning module and laser radar

Abstract

The utility model provides a scanning module and a laser radar. The scanning module is applied to the laser radar comprising a transmitting optical system and a receiving optical system. The scanning module comprises a deflection element used for receiving the laser beam emitted by the emission optical system and deflecting the laser beam to a measured object in a pitching direction; the motor is used for supporting and driving the deflection element to rotate in the azimuth direction and deflecting the laser beam to a measured object in the azimuth direction; the deflection element is also used for receiving laser echoes reflected by the measured object and deflecting the laser echoes to the receiving optical system; and the scanning control panel is electrically connected with the deflection element and / or the motor and is used for controlling the pitching deflection angle of the deflection element and / or controlling the deflection frequency of the deflection element and the rotation frequency of the motor. While the view field range of the laser radar in the horizontal direction is improved, the complexity and the light adjustment difficulty are reduced, and different scanning modes are adaptively switched according to the use scene.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser radar, and more particularly, to a scanning module and a laser radar. BACKGROUND

[0002] There are many existing solutions for implementing two-dimensional scanning of laser radars. In addition to the traditional mechanical rotating multi-line laser radar, none of the existing solutions can achieve scanning of more than 270° in the horizontal direction. The traditional mechanical rotating multi-line laser radar achieves coverage in the vertical direction by stacking multiple groups of transceiving channels, which has relatively high complexity and power consumption, and is difficult to adjust the light. SUMMARY

[0003] The present application is made in view of the above problem, and aims to provide a scanning module and a laser radar, which can improve the horizontal field of view of the laser radar, switch the scanning mode according to different use scenarios, and reduce complexity and light adjustment difficulty.

[0004] In a first aspect, a scanning module is provided, which is applied to a laser radar comprising a transmitting optical system and a receiving optical system. The scanning module comprises: a deflection element, configured to receive a laser beam emitted from the transmitting optical system, and to deflect the laser beam in the vertical direction to a measured object to perform vertical scanning of the measured object; a motor, configured to support and drive the deflection element to rotate in the horizontal direction, and to deflect the laser beam in the horizontal direction to the measured object to perform horizontal scanning of the measured object; the deflection element is further configured to receive a laser echo reflected from the measured object, and to deflect the laser echo to the receiving optical system; and a scanning control board, electrically connected with the deflection element and / or the motor, configured to control a vertical deflection angle of the deflection element, and / or to control a deflection frequency of the deflection element and a rotation frequency of the motor.

[0005] In this embodiment, by using the scanning module in the laser radar, two-dimensional scanning in the horizontal and vertical directions can be achieved only by the deflection element, the motor and the scanning control board, which can improve the horizontal field of view of the laser radar, reduce complexity and light adjustment difficulty, and adaptively switch different scanning modes according to different use scenarios.

[0006] In combination with the first aspect, the deflection element includes a fast-axis torsional beam, a slow-axis torsional beam, and a reflector; and the deflection element deflects the laser beam in the pitch direction to the measured object by rotating the fast-axis torsional beam or the slow-axis torsional beam. By providing the fast-axis torsional beam and the slow-axis torsional beam in the deflection element, different torsional beams can be used according to different deflection frequency requirements, so as to meet the deflection frequency requirements of the deflection element.

[0007] In combination with the first aspect, the deflection element deflects the laser beam in the pitch direction to a scanning field of view with an angle range of 0°-60°, and the motor drives the deflection element to deflect the laser beam in the azimuth direction to a scanning field of view with an angle range of 0°-270°. In the scanning module, the motor is used to drive the deflection element to deflect in the horizontal direction, so as to achieve a larger scanning field of view in the horizontal direction while reducing the complexity.

[0008] In combination with the first aspect, the size of the reflector is greater than the size of the laser beam or the laser echo. By setting the size of the laser beam or the laser echo to be smaller than the size of the reflector, the energy loss can be avoided, the scanning accuracy and resolution and the detection distance are improved, and the overall efficiency of the system is improved.

[0009] In combination with the first aspect, the scanning mode of the scanning module includes a pitch-variable scanning mode, in which the scanning control board drives the deflection element to change the vibration amplitude of the fast-axis torsional beam or the slow-axis torsional beam, changes the pitch deflection angle of the deflection element, and scans the measured object in the pitch-variable scanning mode. In the scanning module, the deflection element driven by the electromagnetic force or the electrostatic force in the pitch direction can change the vibration amplitude of the fast-axis torsional beam and the slow-axis torsional beam in the deflection element by changing the electromagnetic force or the electrostatic force according to different use scenarios, so as to change the pitch deflection angle of the deflection element, i.e., change the pitch field of view (FOV), so as to adapt to the use scenarios.

[0010] In combination with the first aspect, the scanning mode further includes a repeated scanning mode, in which the scanning control board controls the deflection element to perform pitch deflection at a first deflection frequency and controls the motor to perform azimuth rotation at a first rotation frequency, the first deflection frequency is greater than the first rotation frequency, and the first deflection frequency is a positive integer multiple of the first rotation frequency, so as to scan the measured object in the repeated scanning mode. According to different use scenario requirements, the scanning module can perform closed-loop control on the deflection frequency of the deflection element and the rotation frequency of the motor through the scanning control board. When the deflection frequency of the deflection element is higher than the rotation frequency of the motor, and the deflection frequency of the deflection element is a positive integer multiple of the rotation frequency of the motor, the repeated scanning mode can be realized, which reduces the power consumption while meeting the requirements of point cloud angle repeatability in the scene.

[0011] In combination with the first aspect, the scanning mode further includes an encryption scanning mode, wherein the first deflection frequency is a non-integer multiple of the first rotation frequency, so as to scan the object to be measured in the encryption scanning mode. According to the requirement of the use scene, the point cloud angle resolution of the scanning scene needs to be encrypted, and at this time, the scanning module can realize the encryption scanning of the point cloud angle resolution of the scanning scene by controlling the deflection frequency of the deflection element to be a non-integer multiple of the rotation frequency of the motor, so as to obtain more fine scanning results.

[0012] In combination with the first aspect, the scanning mode includes an encryption scanning mode, wherein the scanning control board controls the deflection element to perform the elevation deflection at a second deflection frequency or a third deflection frequency, and controls the motor to perform the azimuth rotation at a second rotation frequency, the second deflection frequency is less than the second rotation frequency, the third deflection frequency is higher than the second rotation frequency, and the second deflection frequency or the third deflection frequency is a non-integer multiple of the second rotation frequency, so as to scan the object to be measured in the encryption scanning mode. According to the requirement of the use scene, the point cloud of the scanning scene needs to be encrypted, and at this time, the scanning module can realize the encryption scanning of the point cloud of the scanning scene by controlling the deflection frequency of the deflection element to be a non-integer multiple of the rotation frequency of the motor, so as to obtain more fine scanning results.

[0013] In combination with the first aspect, the motor is a hollow motor, and the center region of the hollow motor is through; wherein the scanning control board includes a deflection control board and a motor control board arranged on the upper and lower sides of the hollow motor respectively; the deflection control board is electrically connected with the deflection element, and the motor control board is electrically connected with the hollow motor. By arranging the deflection control board and the motor control board to be connected with the deflection element and the motor respectively, more accurate control of the deflection element and the motor can be realized, the light adjustment difficulty is reduced, the motor is arranged as a hollow motor, the overall integration of the inside of the scanning module is improved, the mechanical interference is reduced, and the reliability of the scanning module is improved.

[0014] In combination with the first aspect, wireless optical communication modules are arranged on the deflection control board and the motor control board respectively, so as to realize the bidirectional communication between the deflection control board and the motor control board. By arranging the wireless optical communication modules on the deflection control board and the motor control board respectively, data transmission can be realized through the internal hollow of the hollow motor, so as to realize the real-time control of the motor and the deflection element, and realize the accurate switching of different scanning modes.

[0015] In conjunction with the first aspect, the motor control board also includes a wireless power transmission drive circuit. This circuit is connected to a wireless power transmission transmitting coil, which supplies power to the deflection control board. The deflection control board is connected to a wireless power transmission receiving coil, which supplies power to the deflection control board via non-contact electromagnetic coupling. By using wireless power transmission transmitting and receiving coils, power transmission between the deflection control board and the motor control board can be achieved, reducing wiring and increasing the internal integration of the scanning module while reducing complexity.

[0016] In conjunction with the first aspect, the deflection control board transmits a drive signal to the deflection element to drive it to perform pitch deflection. Specifically, the deflection control board uses the synchronously sampled deflection angle of the deflection element as a feedback signal to modulate the deflection amplitude of the deflection element, thereby achieving closed-loop control of the pitch scan. The deflection control board controls the pitch deflection element through the drive signal, while simultaneously acquiring the pitch deflection information of the deflection element and generating new drive signals based on the acquired deflection information. This achieves closed-loop control of the pitch scan, reducing interference during the control process, making the pitch scan more accurate and stable, and improving the reliability of the scanning module.

[0017] In conjunction with the first aspect, the deflection control board is also used to acquire encoder information from the motor, including the motor's rotation frequency and rotation angle. Based on this encoder information, the deflection control board generates a frequency control signal, which is used to adjust the deflection frequency of the deflection element to switch between repetitive and encrypted scanning modes for the scanning module. Through these settings, the deflection control board can acquire encoder information from the motor in real time and use this information to control the deflection frequency of the deflection element, enabling real-time switching and adjustment between repetitive and encrypted scanning modes, thus improving the scanning module's adaptability and reliability in various scenarios.

[0018] In a second aspect, a lidar is provided, comprising: a scanning module as described in any of the first aspects; and a transceiver module, the transceiver module comprising a transmitting optical system for emitting a laser beam toward a test object, and a receiving optical system for receiving a laser echo reflected back from the test object.

[0019] In conjunction with the second aspect, the transceiver module also includes a light guide prism, comprising: a transmitting optical system for emitting a collimated and compressed laser beam to the light guide prism, which then guides the laser beam to the scanning module; the scanning module deflects the laser beam toward the object under test; and a receiving optical system for receiving the laser echo reflected back from the object under test by the scanning module. The transmitting optical system, light guide prism, and scanning module are arranged from top to bottom, with their centers aligned on a straight line. By arranging the transmitting optical system, light guide prism, and scanning module from top to bottom, and ensuring their centers are aligned on a straight line, the linearity of the laser light path can be maximized, improving radar scanning accuracy while reducing the complexity of the lidar.

[0020] In conjunction with the second aspect, the transceiver module also includes a hollow reflector. A light-guiding prism passes through the hollow reflector, which is used to reflect the laser echo deflected by the scanning module and returned to the receiving optical system. By setting a hollow reflector on the light-guiding prism, the internal structure of the lidar can be optimized, reducing the complexity of the lidar while ensuring scanning accuracy.

[0021] In conjunction with the second aspect, the lidar also includes a main control processing board and a transceiver control board. The main control processing board controls the scanning control board to control the scanning module to switch scanning modes, while the transceiver control board controls the transmitting optical system to emit the laser beam and controls the receiving optical system to receive the laser echo reflected back from the object being measured. By setting up the main control processing board and the transceiver control board, the reliability and accuracy of the lidar are improved, while the integration of the lidar is increased, and the complexity and light tuning difficulty are reduced. Attached Figure Description

[0022] Figure 1 This is a schematic structural block diagram of the lidar provided in the embodiments of this application.

[0023] Figure 2 This is a schematic block diagram of the circuit structure of the lidar provided in the embodiments of this application.

[0024] Figure 3 This is a schematic exploded view of the lidar bracket provided in the embodiments of this application.

[0025] Figure 4 This is a schematic diagram of the structure of the lidar provided in the embodiment of this application.

[0026] Figure 5 This is another structural schematic diagram of the lidar provided in the embodiments of this application.

[0027] Figure 6 This is another structural schematic diagram of the lidar provided in the embodiments of this application.

[0028] Figure 7 This is another structural schematic diagram of the lidar provided in the embodiments of this application.

[0029] Figure 8 This is a schematic diagram of the deflection element provided in the embodiments of this application.

[0030] Figure 9 This is another structural schematic diagram of the lidar provided in the embodiments of this application.

[0031] Figure 10 This is a partial structural schematic diagram of the lidar provided in an embodiment of this application.

[0032] Figure 11 This is a schematic diagram of the scanning range of the lidar provided in the embodiments of this application.

[0033] Figure 12 This is a schematic diagram of the scanning trajectory of the lidar provided in the embodiments of this application.

[0034] Figure 13 This is another structural schematic diagram of the lidar provided in the embodiments of this application.

[0035] Figure 14 This is a schematic diagram of the ranging principle of the lidar provided in the embodiments of this application.

[0036] Figure 15 This is another schematic diagram of the ranging principle of the lidar provided in the embodiments of this application.

[0037] Figure 16 This is a schematic diagram illustrating the principle of the walking error of the lidar provided in the embodiments of this application.

[0038] Figure 17 This is a flowchart illustrating the error calibration method provided in the embodiments of this application.

[0039] Figure 18 This is another flowchart illustrating the error calibration method provided in the embodiments of this application.

[0040] Figure 19 This is a flowchart illustrating the error compensation method provided in the embodiments of this application. Detailed Implementation

[0041] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0042] In the description of the embodiments in this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In this application, "at least one" means one or more, and "more" means two or more.

[0043] The use of prefixes such as "first" and "second" in this application embodiment is solely for distinguishing different descriptive objects and does not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes to distinguish descriptive objects in this application embodiment does not constitute a limitation on the described objects. The description of the described objects is found in the claims or the context of the embodiments, and the use of such prefixes should not constitute unnecessary restrictions.

[0044] To keep the drawings concise, the figures in this application only schematically show the parts related to the corresponding embodiments, and they do not represent the actual structure of the product. In addition, to make the drawings concise and easy to understand, some figures only schematically show some structures or components, and there may actually be more or fewer identical or similar structures or components.

[0045] In some related technologies, lidar often suffers from problems such as a small azimuth scanning range, high complexity and power consumption in elevation scanning implementation, and stray light interference. Based on this, this application proposes a lidar that enables a wide scanning range, reduces stray light interference, and has lower structural complexity.

[0046] Figure 1 A schematic structural block diagram of a lidar provided in an embodiment of this application. In some embodiments, such as Figure 1As shown, the lidar 1 provided in this embodiment may include a transceiver module 1100, a scanning module 1200, and a main control processing board 1300 arranged from top to bottom. The lidar 1 also includes a transceiver control board 1400. The transceiver module 1100 includes a transmitting optical system 1110 for emitting a laser beam towards the object under test 2 and a receiving optical system 1120 for receiving the laser echo reflected back from the object under test 2. The scanning module 1200 is used to deflect the laser beam emitted by the transmitting optical system 1110 towards the object under test 2, and to receive the laser echo reflected back from the object under test 2 and deflect it to the receiving optical system 1120. The main control... The processing board 1300 includes a control processor 1310 and a microprocessor 1320. The control processor 1310 is used to control the transceiver control board 1400 to acquire timing data of the laser beam from emission to reception. The microprocessor 1320 is used to control the scanning module 1200 and to perform distance resolution on the timing data to obtain point cloud data of the object under test 2. The transceiver control board 1400 is used, under the control of the control processor 1310 of the main control processing board 1300, to drive the transmitting optical system 1110 of the transceiver module 1100 to emit the laser beam, and to amplify and process the laser echo received by the receiving optical system 1120 of the transceiver module 1100.

[0047] Through the above-described embodiments, the coordinated operation of the various components of the lidar provided in this application can achieve a scanning range of at least 270° in the azimuth direction and 60° in the elevation direction, while maintaining low complexity and power consumption. The following is a brief introduction to each module in lidar 1.

[0048] Optionally, the transceiver control board 1400 may include a laser emitting board 1410 and a detection and receiving board 1420. The laser emitting board 1410 is located at the beginning of the emitting optical path of the emitting optical system 1110 and is electrically connected to the emitting optical system 1110. Under the control of the control processor 1310 of the main control processing board 1300, the laser emitting board 1410 drives the emitting optical system 1110 to emit a laser beam. The detection and receiving board 1420 is located at the end of the receiving optical path of the receiving optical system 1120 and is electrically connected to the receiving optical system 1120. Under the control of the control processor 1310 of the main control processing board 1300, the detection and receiving board 1420 amplifies and processes the laser echo received by the receiving optical system 1120.

[0049] In the above embodiment, the transceiver control board 1400 is controlled by the main control processing board 1300, so that the transceiver module 1100 can transmit and receive the laser beam at a predetermined time and power under the control of the main control processing board 1300, and use the receiving optical system 1120 to receive the reflected laser echo, thereby realizing accurate measurement of the object under test 2.

[0050] Furthermore, regarding the spatial structure of the LiDAR 1, the transceiver control board 1400 can be located at the position of the transceiver module 1100, which reduces the number of external lines connecting the transceiver control board 1400 and the transceiver module 1100. Compared to separating the transceiver control board 1400 and the transceiver module 1100, this arrangement reduces electromagnetic interference between lines and improves the stability of the entire LiDAR 1 system.

[0051] In the above specific embodiment, the laser emitting plate 1410 is close to the emitting optical system 1110, which optimizes the integrated layout and allows for more precise control of the laser beam emission parameters. During the receiving process, the detection receiving plate 1420 is close to the receiving optical system 1120, which can more accurately receive and process the reflected laser echo, reducing measurement deviations caused by signal transmission errors and optical system alignment errors.

[0052] Figure 2 This is a schematic block diagram of the circuit structure of a lidar provided in an embodiment of this application.

[0053] Optionally, such as Figure 2 As shown, the lidar 1 may also include a power interface board 1500, which is used to connect to a power source and is electrically connected to the transceiver control board 1400 and the main control processing board 1300 respectively. The power interface board 1500 provides power to the transceiver control board 1400 under the control of the main control processing board 1300.

[0054] Optionally, the transceiver control board 1400’s detector receiver board 1420 is electrically connected to the power interface board 1500, and the transceiver control board 1400’s laser emitter board 1410 is electrically connected to the detector receiver board 1420, so that the laser emitter board 1410 provides power to the laser emitter of the transmitting optical system 1110 through the detector receiver board 1420.

[0055] The lidar 1 supplies power to other modules through the power interface board 1500. The electrical connections between the power interface board 1500 and other modules, as well as between modules, can be achieved through flexible printed circuit (FPC) cables.

[0056] Through the above implementation, the power interface board 1500 can supply power to the detection receiver board 1420, which can then transmit power to the laser emitter board 1410 via an FPC cable. This achieves the effect of the power interface board 1500 indirectly supplying power to the laser emitter through the detection receiver board 1420, without adding additional circuit wiring. Optionally, the power interface board 1500 can be located at the detection receiver board 1420.

[0057] The above implementation makes it easier to distribute the cabling between the power interface board 1500 and the detection receiver board 1420, reduces the structural complexity of the lidar, and avoids excessively long cabling affecting the setup of other components.

[0058] Figure 3 This is a schematic exploded view of the mounting bracket for the lidar provided in an embodiment of this application. Figure 3 As shown, the laser emitting board 1410 is fixedly connected to the emitting optical system and fixed in the lidar via the emitting mounting bracket 1113; the detection receiving board 1420 is fixedly connected to the receiving optical system and fixed in the lidar via the receiving mounting bracket 1124, and the laser emitting board 1410 and the detection receiving board 1420 can be electrically connected via an FPC (not shown in the figure); the power interface board 1500 is a recessed circuit board, and the recessed part can be precisely fitted with the detection receiving board 1420, so that the power interface board 1500 and the detection circuit board 1500 share a single receiving mounting bracket to be fixed in the lidar, thereby reducing the use of structural components and miniaturizing the lidar.

[0059] Furthermore, during the operation of a lidar system, a significant amount of heat is typically generated, with the laser emitting board and laser transmitter experiencing particularly high heat. Therefore, optionally, the laser emitting board 141 can be a circuit board based on Rogers board material; alternatively, a thermally conductive copper sheet can be provided on the laser emitting board 1410; or the transmitting mounting bracket 1113 or the receiving mounting bracket 1124 can be a metal mounting bracket. The high thermal conductivity of copper sheets can dissipate the heat generated by the lidar, reducing the temperature of the laser emitting board or the detector / receiver board; metal has excellent thermal conductivity, increasing the effective heat dissipation volume and rapidly dissipating heat.

[0060] It should be understood that the above implementation methods may be used only one of them, or in any combination.

[0061] Continue to refer to Figure 2 The microprocessor 1320 in the main control processing board 1300 can control the lidar 1 and can communicate bidirectionally with the host computer. That is, the microprocessor 1320 can receive the working parameter instructions from the host computer and pass them to other modules, and can also feed back the data generated by other modules to the host computer. The bidirectional communication process can be implemented based on the user datagram protocol (UDP).

[0062] During the bidirectional communication between the microprocessor 1320 and the host computer, the host computer can adjust the operating parameters of the lidar 1, such as emission power, pulse frequency, and scanning angle, according to the actual measurement environment and application requirements, enabling the lidar 1 to adapt to complex and changing scenarios. Furthermore, through data feedback, the host computer can also obtain the operating status parameters of the lidar 1 for analysis and processing, or further adjust the parameters of the lidar 1. The microprocessor 1320 can also perform distance calibration, intensity / reflectivity calibration, and other distance resolution processing on the timing data obtained from the control processor 1310, forming point cloud data such as distance, intensity / reflectivity. Optionally, the microprocessor 1320 in the main control processing board 1300 can be a microcontroller unit (MCU).

[0063] The control processor 1310 in the main control processing board 1300 is typically used to acquire timing data from the lidar 1. In some embodiments, the control processor 1310 may include a transmission timing control module 1311 and a time-to-digital converter module 1312. The transmission timing control module 1311 may be used to transmit a firing signal to the laser emitting board 1410 in the transceiver control board 1400; the time-to-digital converter module 1312 may be used to generate timing data to be sent to the microprocessor 1320. The timing data may include information such as the pulse intensity and flight time of the laser beam.

[0064] For example, the emission timing control module 1311 transmits a firing signal to the laser emitting board 1410. After receiving the firing signal, the laser emitting board 1410 controls the emission optical system 1110 to generate a high-frequency, high-power, nanosecond-level light pulse signal and emits it to the test object 2. At the same time, it sends a start signal to the time digital conversion module 1312. The test object 2 reflects the light pulse signal to form a laser echo, which is received by the receiving optical system 1120, so that the detection receiving board 1420 generates a stop signal and transmits it to the time digital conversion module 1312. The time digital conversion module uses the start signal and the stop signal to obtain the timing data and transmits it to the microprocessor 1320.

[0065] In the above process, the transmission timing control module can cooperate with the transceiver control board 1400 to drive the transceiver module 1100 to transmit and receive laser pulses, and the time-to-digital conversion processing is completed by the control processor 1310. This avoids the use of application-specific integrated circuit (ASIC) time-to-digital converter (TDC) chips, and can guarantee high point frequencies above 100 kHz, reducing costs and simplifying the internal structure of the lidar system. Optionally, the control processor 1310 can be a field-programmable gate array (FPGA).

[0066] In some embodiments, the lidar 1 may further include a base, and the main control processing board 1300 is typically disposed inside the lidar base. This helps to reduce the impact of heat generation during operation on the operation of other internal components of the lidar. Furthermore, the control processor 1310 and microprocessor 1320 of the main control processing board 1300 can respectively be in close contact with the inside of the base via thermal pads, so that the heat generated by the control processor 1310 and microprocessor 1320 during operation can be transferred to the base via the thermal pads and diffused outwards through the base, thereby improving the heat dissipation performance of the lidar.

[0067] Optionally, the scanning module 1200 may include a deflection element 1210, a motor 1220, and a scanning control board 1230. The scanning control board 1230 includes a deflection control board 1231 and a motor control board 1232 arranged from top to bottom. The motor control board 1232 is electrically connected to the power interface board 1500. The motor control board 1232 is connected to a wireless power transmission transmitting coil, and the deflection control board 1231 is connected to a wireless power transmission receiving coil. The wireless power transmission transmitting coil and the wireless power transmission receiving coil provide power to the deflection control board 1231 through the principle of electromagnetic induction, so that the deflection element 1210 and the motor 1220 in the scanning module 1200 can be driven respectively through the deflection control board 1231 and the motor control board 1232, thereby realizing two-dimensional scanning of the scanning module 1200.

[0068] The motor 1220, which serves as the driving element for the scanning module 1200, includes a stator and a rotor. The motor control board 1232 is electrically connected to the power interface board 1500 to obtain power, energizing the wireless power transmission coil on the motor control board 1232 to generate a magnetic field. The wireless power receiving coil on the deflection control board 1231 is located within this magnetic field. Changes in the magnetic field provide power to the deflection control board 1231, enabling wireless power transmission to the deflection control board 1231. The motor control board 1232 drives the motor rotor to rotate, causing the deflection control board 1231 and the deflection element 1210 to rotate horizontally under the drive of the motor 1220 rotor, achieving horizontal (i.e., azimuth) scanning of the lidar. Preferably, the motor 1220 in this application is a brushless DC motor, which can achieve magnetic field changes through electronic commutation and current control.

[0069] The above implementation simplifies the wiring structure inside the lidar system, providing greater flexibility for system layout and design.

[0070] In some embodiments, during the operation of the lidar, the microprocessor 1320 in the main control processing board 1300 can connect to the scanning control board 1230 in the scanning module 1200 via a universal asynchronous receiver / transmitter (UART) interface. Under the control of the main control processing board, the scanning control board controls the scanning module to switch scanning modes. In other words, the microprocessor 1320 can connect to the motor control board via the UART interface to control the working state of the motor, and connect to the deflection control board via wireless optical communication to control the working state of the deflection element. For example, the microprocessor 1320 can transmit working state parameters such as motor speed and the vertical scanning field of view (FOV) of the deflection element to the scanning control board 1230, and control the deflection element 1210 or the motor 1220 through the scanning control board 1230. Furthermore, the microprocessor 1320 can also acquire data such as the real-time rotation angle of the motor 1220 and the angle of the deflection element 1210 in the scanning module 1200, and transmit them to the host computer for analysis and processing.

[0071] Based on this, the scanning module can quickly adjust the scanning parameters according to actual application needs, meeting the high-precision scanning requirements of diverse application scenarios.

[0072] The following section will provide a detailed introduction to the various components of a lidar system, using a schematic diagram as an example.

[0073] Figure 4 This is a schematic diagram of a lidar structure provided in an embodiment of this application. Figure 4As shown in the figure, a lidar 1 provided in this application includes a transmitting optical system 1110, a light guide prism 1130, a scanning module 1200, and a receiving optical system 1120. The transmitting optical system 1110, the light guide prism 1130, and the scanning module 1200 are arranged from top to bottom, and the centers of the three are located on the same straight line. It should be understood that the lidar transmitting optical system 1110, the receiving optical system 1120, and the light guide prism 1130 can also be referred to as a transceiver module 1100; the light guide prism 1130 can also be replaced by an optical fiber, a light guide rod, or a hollow columnar structure, which is not limited in this application.

[0074] In some embodiments, the emitting optical system 1110 is used to emit a collimated and compressed laser beam to the light guide prism 1130. It may include a laser emitter 1111 and a collimating lens 1112. The laser emitter 1111 is used to emit a laser beam to the collimating lens 1112, and the collimating lens 1112 is used to collimate and compress the laser beam emitted by the laser emitter 1111 to obtain a collimated and compressed laser beam.

[0075] It should be noted that collimating and compressing the laser beam includes, but is not limited to, collimating the laser beam into approximately parallel light in the fast axis direction and / or collimating the laser beam into approximately parallel light in the slow axis direction. For example, after the laser beam undergoes collimation along the fast axis and / or the slow axis, the final emitted laser beam is approximately parallel light. The above is merely an illustrative description and is not intended to limit the scope of this application.

[0076] It is understood that the laser emitter 1111 in the embodiments of this application can be a single or arrayed edge-emitting laser (EEL) to emit a laser beam with a large divergence angle, or a single or arrayed vertical-cavity surface-emitting laser (VCSEL), or a fiber laser to emit a circular laser beam; the detector can be an avalanche photodiode detector (APD), an avalanche photodiode array (also called an APD array), a silicon photomultiplier (SiPM), a silicon photomultiplier array (also called a SiPM array), a single photon avalanche diode (SPAD) array, etc., and this application does not limit it.

[0077] Figure 5 This is another structural schematic diagram of a lidar provided as an embodiment of this application. For example... Figure 5As shown, the collimating lens 1112 in the transmitting optical system 1110 may include a fast-axis collimating lens 1112a and a slow-axis collimating lens 1112b. The fast-axis collimating lens 1112a is used to collimate the fast-axis divergence angle of the laser beam emitted by the laser emitter 1111, and the slow-axis collimating lens 1112b is used to collimate the slow-axis divergence angle of the laser beam emitted by the laser emitter 1111, so as to form a laser beam with a small divergence angle.

[0078] In one possible scenario, the laser beam emitted by laser emitter 1111 first passes through fast-axis collimating lens 1112a, and then through slow-axis collimating lens 1112b. As an example, the fast-axis divergence angle of the laser beam emitted by laser emitter 1111 is first collimated by fast-axis collimating lens 1112a, and then the slow-axis divergence angle of the laser beam after fast-axis divergence collimation is collimated by slow-axis collimating lens 1112b.

[0079] In another possible scenario, the laser beam emitted by laser emitter 1111 first passes through slow-axis collimating lens 1112b, and then through fast-axis collimating lens 1112a. As an example, the slow-axis divergence angle of the laser beam emitted by collimating laser emitter 1111 is first collimated by slow-axis collimating lens 1112b, and then the fast-axis divergence angle of the laser beam emitted by collimating laser emitter 1111 is collimated by fast-axis collimating lens 1112a.

[0080] It should be noted that the fast-axis collimating lens 1112a and the slow-axis collimating lens 1112b in the embodiments of this application can be set independently or integrated into each other. The fast-axis collimating lens 1112a and / or the slow-axis collimating lens 1112b can also be integrated with the laser emitter 1111. This application does not limit this.

[0081] In the above technical solution, before the laser beam is emitted from the light guide prism by the transmitting optical system, the fast axis divergence angle and / or slow axis divergence angle of the laser beam before emission are collimated and compressed to compress the spot size of the laser beam. This reduces the aperture of the light guide prism, thereby reducing the area of ​​the light guide prism blocking the receiving optical path, improving the overall transceiver efficiency of the lidar, and also reducing the space occupied by the module in the lidar.

[0082] In some embodiments, a single spherical / aspherical collimating lens or a group of spherical / aspherical collimating lenses may be disposed between the laser emitter 1111 and the fast-axis collimating lens 1112a, or the fast-axis collimating lens 1112a may be integrated with the spherical / aspherical collimating lens.

[0083] In the above technical solution, before the fast-axis collimating lens collimates the laser beam emitted by the laser emitter, the fast axis of the laser beam can be partially collimated to improve the collimation and compression quality of the laser beam emitted by the laser emitter.

[0084] Return to reference Figure 4 The laser radar light guide prism 1130 proposed in this application includes an input region, a transmission region, and an output region. The input region is used to input the collimated and compressed laser beam into the transmission region. The transmission region is used to transmit the laser beam to the output region. The output region is used to output the laser beam transmitted by the transmission region to the scanning module 1200, so that the scanning module 1200 deflects the laser beam to the object under test 2.

[0085] As an example, the laser beam emitted by the laser emitter 1111 after being collimated and compressed by the collimating lens 1112 is coupled into the transmission region of the light guide prism 1130 by the coupling region of the light guide prism 1130. The transmission region of the light guide prism 1130 transmits the laser beam to the coupling region of the light guide prism 1130, and the laser beam is coupled out from the coupling region of the light guide prism 1130 to the scanning module 1200.

[0086] In the above technical solution, the laser beam is transmitted to the scanning device through the light guide prism. The laser beam will not act on other structural components and / or reflectors of the lidar, which effectively reduces stray light generated by the laser beam due to various reflections from other structural components, dielectric film reflectors, etc., and improves the short-range ranging capability of the lidar.

[0087] Optionally, the coupling-in and / or coupling-out regions of the light guide prism 1130 are provided with an anti-reflection film, or the coupling-in and / or coupling-out regions of the light guide prism 1130 are provided with an anti-reflection film and polished. The design wavelength of the anti-reflection film is determined based on the wavelength of the collimated and compressed laser beam emitted by the transmitting optical system 1110. By providing an anti-reflection film in the coupling-in and / or coupling-out regions of the light guide prism, the optical efficiency of the laser beam passing through the light guide prism can be improved, and the scattering or refraction of the laser beam within the light guide prism can be reduced, thereby reducing stray light generation and improving the coupling-in and / or coupling-out efficiency of the laser beam within the light guide prism. Furthermore, polishing the end face with the anti-reflection film can reduce roughness, further reducing stray light generation and improving the coupling-in and / or coupling-out efficiency of the laser beam within the light guide prism.

[0088] In some embodiments, the sidewalls of the transmission area of ​​the light guide prism 1130 are coated with a light-absorbing ink layer, wherein the thickness of the light-absorbing ink layer is sufficient to ensure that no light leaks when the laser beam propagates in the transmission area of ​​the light guide prism 1130, which is not required in this application.

[0089] In the above technical solution, the light guide prism is coated with a light-absorbing ink layer on the side wall of the transmission area, so that the laser beam transmitted inside the light guide prism will not leak out. In addition, the smaller thickness of the light-absorbing ink layer can reduce the area of ​​the light guide prism blocking the receiving optical path and improve the overall transceiver efficiency of the lidar.

[0090] In the above embodiment, the laser beam emitted by the collimated and compressed laser emitter 1111 is coupled into the transmission region of the light guide prism 1130 by the coupling region of the light guide prism 1130. The transmission region of the light guide prism 1130 transmits the laser beam to the coupling region of the light guide prism 1130. The laser beam is coupled out from the coupling region of the light guide prism 1130 to the scanning module 1200, so that the scanning module 1200 can deflect the laser beam to the object under test 2 and realize the scanning of the object under test 2.

[0091] In some embodiments, the receiving optical system 1120 includes a focusing lens 1121 and a detector 1122 located on the focal plane of the focusing lens 1121. The focusing lens 1121 can be used to converge the laser echo reflected back from the object under test 2, which is received and deflected by the scanning module 1200, onto the detector 1122.

[0092] Optionally, the detector 1122 can be an avalanche photodiode detector. The incident light side of the avalanche photodiode detector can also be provided with a filter so that only the laser echo reflected back by the object under test 2 enters the detector 1122, thereby reducing the influence of stray light caused by the high reflectivity of the non-detection area of ​​the avalanche photodiode detector.

[0093] Optionally, the receiving optical system 1120 may further include a receiving aperture 1123. The receiving aperture 1123 is disposed on the incident light side of the detector 1122 to block stray light from entering the detector 1122; wherein, the receiving aperture 1123 may be integrated with the focusing lens 1121, or the receiving aperture 1123 may be disposed independently of the focusing lens 1121. It should be understood that the incident light side of the detector 1122 includes, but is not limited to, positions at any distance from the detector 1122.

[0094] In the above technical solution, a receiving aperture is set on the light-incident side of the detector, which can block most of the stray light and ambient light generated by multiple reflections of the laser beam between the structural components of the lidar from entering the detector without blocking the laser echo reflected back by the object being measured.

[0095] In some embodiments, the transceiver module 1100 may further include a hollow reflector 1140, which is disposed at the intersection of the transmitting optical path of the transmitting optical system 1110 and the receiving optical path of the receiving optical system 1120, so as to reflect the laser echo reflected back by the object under test 2 to the receiving optical system 1120.

[0096] As an example, the laser echo received by the scanning module 1200 and reflected back by the object under test 2 is deflected to the hollow reflector 1140. The reflection by the hollow reflector 1140 forms part of the receiving optical path of the receiving optical system 1120. This part of the receiving optical path is not coaxial with the emitting optical path of the emitting optical system 1110. That is, the hollow reflector 1140 is located at the intersection of the coaxial optical paths of the emitting optical system 1110 and the receiving optical path of the receiving optical system 1120.

[0097] Therefore, the hollow reflector 1140 also includes a through hole located at the center of the hollow reflector 1140, and the light guide prism 1130 passes through the through hole located at the center of the hollow reflector 1140, so that the emitting optical path of the emitting optical system 1110 and the receiving optical path of the receiving optical system 1120 are coaxial.

[0098] As an example, the light guide prism 1130 passes through the through hole located at the center of the hollow reflector 1140. The position of the hollow reflector 1140 on the light guide prism 1130 allows the emitting optical path of the emitting optical system 1110 to be coaxial with the receiving optical path of the receiving optical system 1120 before being reflected by the hollow reflector 1140.

[0099] Alternatively, the hollow reflector 1140 and the light guide prism 1130 are arranged at a 45° angle at the intersection of the emitting optical path of the emitting optical system 1110 and the receiving optical path of the receiving optical system 1120.

[0100] As an example, when the light guide prism 1130 passes through the through-hole located at the center of the hollow reflector 1140, the hollow reflector 1140 is tilted at a 45° angle to the sidewall of the light guide prism 1130 (or, the side parallel to the laser beam transmitted within the light guide prism 1130), to reflect the laser echo reflected back from the object under test 2 to the detector 1122. The position of the hollow reflector 1140 on the light guide prism 1130 allows the emitting optical path of the emitting optical system 1110 to be coaxial with the receiving optical path of the receiving optical system 1120 before reflection by the hollow reflector 1140.

[0101] In some embodiments, before the laser echo is reflected by the hollow mirror 1140, the optical axis of the transmitting optical system 1110 is parallel to the optical axis of the receiving optical system 1120; and / or, the optical axis of the transmitting optical system 1110 before the laser beam is deflected by the scanning module 1200 is perpendicular to the optical axis of the receiving optical system 1120 after the laser echo is reflected by the hollow mirror 1140.

[0102] It should be noted that before the laser echo is reflected by the hollow reflector 1140, the optical axis of the transmitting optical system 1110 is parallel to the optical axis of the receiving optical system 1120. This can be between the hollow reflector 1140 and the scanning module 1200, where the optical axis of the transmitting optical system 1110 before the laser beam is deflected by the scanning module 1200 is parallel to the optical axis of the receiving optical system 1120 after the laser echo is deflected by the scanning module 1200; or it can be between the scanning module 1200 and the object under test 2, where the optical axis of the transmitting optical system 1110 after the laser beam is deflected by the scanning module 1200 is parallel to the optical axis of the receiving optical system 1120 before the laser echo is deflected by the scanning module 1200.

[0103] In the above technical solution, the combination of a light-guiding prism and a hollow reflector isolates the transmitting and receiving optical paths, thereby reducing the influence of stray light on the laser beam in the transmitting optical path, and simultaneously reducing the influence of stray light on the laser echo in the receiving optical path. Furthermore, the light-guiding prism passing through the through-hole of the hollow reflector compresses the laser beam spot size and makes the transmitting and receiving optical paths coaxial, thus reducing the space occupied by the lidar module and facilitating its miniaturization.

[0104] In some embodiments, the light guide prism 1130 further includes a shielding structure 1150, which is sleeved on the coupling area side near the light guide prism 1130 to shield stray light from the scanning module 1200.

[0105] As an example, a shielding structure 1150 is fitted at the opening of the transceiver module 1100 (i.e., near the coupling area side of the light guide prism 1130) to shield stray light from the scanning module 1200.

[0106] In the above technical solution, by installing a shielding structure on the coupling area side of the light guide prism located at the opening of the transceiver module, stray light from the scanning module can be prevented from entering the detector of the lidar, thereby improving the processing accuracy of the lidar.

[0107] In another embodiment of the lidar provided in this application, the lidar can be combined with a hollow focusing lens and a light guide prism to isolate the optical axis of the transmitting optical system and the optical axis of the receiving optical system.

[0108] Figure 6 This is another structural schematic diagram of a lidar provided in an embodiment of this application. For example... Figure 6 As shown, the lidar 3 includes a transceiver module 3100 and a scanning module 3200. The transceiver module 3100 includes a transmitting optical system 3110, a light guide prism 3130, and a receiving optical system 3120; and Figure 5The difference between the receiving optical system 1120 described in the embodiment and the receiving optical system 1120 is that Figure 6 In the receiving optical system 3120 shown, the focusing lens is a hollow focusing lens 3121, and the light guide prism 3130 is embedded in the mounting hole at the center of the hollow focusing lens 3121. It should be understood that the other identical structural components and functions in the receiving optical system 3120 and the transmitting optical system 3110 can be referred to the above content, and will not be repeated here.

[0109] In some embodiments, the light guide prism 3130 may further include a reflection region 3131 for reflecting a laser beam coupled from the coupling region of the light guide prism 3130 to the transmission region of the light guide prism 3130.

[0110] As an example, the hollow focusing lens 3121 is provided with a mounting hole for mounting the light guide prism 3130. The collimated and compressed laser beam emitted by the emitting optical system 3110 is coupled into the reflection area 3131 of the light guide prism 3130 by the coupling area of ​​the light guide prism 3130. The laser beam is reflected by the reflection area 3131 of the light guide prism to the transmission area of ​​the light guide prism 3130. Thus, by making the laser beam transmit within the light guide prism 3130 embedded in the mounting hole at the center of the hollow focusing lens 3121, the emission optical path of the emitting optical system 3110 is realized to pass through the center position of the hollow focusing lens 3121.

[0111] In the above technical solution, a hollow focusing lens and a light guide prism can be combined to isolate the optical axis of the transmitting optical system and the optical axis of the receiving optical system, thereby reducing the module configuration cost of the lidar.

[0112] In another embodiment of the lidar provided in this application, the lidar can isolate the optical axis of the transmitting optical system and the optical axis of the receiving optical system using only a light guide prism.

[0113] Figure 7 This is another structural schematic diagram of a lidar provided in an embodiment of this application. For example... Figure 7 As shown, the lidar 4 includes a transceiver module 4100 and a scanning module 4200. The transceiver module 4100 includes a transmitting optical system 4110, a light guide prism 4130, and a receiving optical system 4120. The structure and function of the receiving optical system 4120 and the transmitting optical system 4110 can be referred to the above content, and will not be repeated here.

[0114] Optionally, the light guide prism 4130 is a trapezoidal prism capable of total internal reflection. In some embodiments, the coupling region of the light guide prism 4130 is attached to the central region of the focusing lens 4121, so that the coupling region of the light guide prism 4130 couples the laser beam along the optical axis of the focusing lens 4121 to the focusing lens 4121.

[0115] As an example, the collimated and compressed laser beam emitted by the emitting optical system 4110 is coupled into the transmission region of the light guide prism 4130 by the coupling region of the light guide prism 4130. The transmission region of the light guide prism 4130 can totally reflect the laser beam to its coupling region. The laser beam is coupled out from the coupling region of the light guide prism 4130 to the focusing lens 4121. The focusing lens 4121 collimates the laser beam coupled out from the coupling region of the light guide prism 4130 and transmits it to the scanning module 4200.

[0116] In the above technical solution, the optical axes of the transmitting optical system and the receiving optical system can be isolated using only the light guide prism. Furthermore, the focusing lens in the above technical solution can also be used to collimate the laser beam coupled from the coupling area of ​​the light guide prism and transmit it to the scanning module, thereby reducing the module configuration cost of the lidar.

[0117] Return to reference Figure 4 The scanning module 1200 of the lidar proposed in this application includes a deflection element 1210 and a motor 1220. The deflection element 1210 is used to receive the laser beam transmitted by the light guide prism 1130 and deflect the laser beam to the object under test 2 for elevation scanning. The motor 1220 is used to drive the deflection element 1210 to rotate to deflect the laser beam for azimuth scanning. The deflection element 1210 is also used to receive the laser echo reflected back by the object under test 2 and deflect the laser echo to the receiving optical system 1120. Among them, elevation scanning refers to the scanning module 1200 scanning in the vertical direction; azimuth scanning refers to the scanning module 1200 scanning in the horizontal direction.

[0118] During the scanning process of the lidar, the motor 1220 provides support for the deflection element 1210 and drives the deflection element 1210 to rotate in the horizontal direction, so that the deflection element 1210 can deflect the collimated and compressed laser beam emitted by the emitting optical system 1110 to the object under test 2 in the horizontal direction, so as to realize the azimuth scanning of the object under test 2.

[0119] Optionally, the motor 1220 drives the deflection element 1210 to deflect the laser beam in the azimuth direction, and the scanning field of view of the object under test 2 is within the range of 0° to 270°. That is, the scanning module 1200 of the lidar 1 can cover and scan the object under test 2 in the horizontal direction within the range of 0° to 270°. This field of view determines the range of the object under test 2 that the lidar 1 can detect in a horizontal plane. It should be understood that the angle of the azimuth scanning field of view of the object under test 2 can be 0°, 10°, 40°, 80°, 100°, 120°, 160°, 180°, 200°, 240°, 270°, or any value within the range of 0° to 270°, or even exceed 270°. This application does not impose any limitation on this.

[0120] In the above embodiments, the scanning module uses a motor 1220 to drive the deflection element 1210 to deflect in the horizontal direction, which can reduce the structural complexity of the lidar while achieving a larger scanning field of view in the azimuth direction for the object 2 under test.

[0121] Figure 8 This is a schematic diagram of the structure of a deflection element provided in an embodiment of this application. Figure 8 As shown, the deflection element includes a fast-axis torsion beam 1211, a slow-axis torsion beam 1212, and a reflector 1213. When the laser beam is incident on the reflector 1213, the laser beam is reflected to the object under test 2. By rotating the fast-axis torsion beam 1211 or the slow-axis torsion beam 1212, the laser beam scans the object under test 2 in the pitch direction.

[0122] It should be understood that the rotation of the fast-axis torsion beam 1211 or the slow-axis torsion beam 1212 depends on the pitch orientation of the torsion beam of the deflection element. In this embodiment, the deflection of the reflector 1213 in the pitch direction can be controlled by rotating the torsion beam alone. Correspondingly, the deflection of the reflector 1213 in the azimuth direction can be achieved by a motor rather than the torsion beam.

[0123] In some embodiments, the reflector 1213 can reflect and deflect the laser beam or laser echo. The size of the reflector 1213 is larger than the size of the laser beam or laser echo. The size of the laser beam or laser echo refers to the spot size of the laser beam or laser echo on the reflector, and the size of the reflector refers to the size of the reflective plane of the reflector. By setting the size of the laser beam or laser echo to be smaller than the size of the reflector 1213, energy loss can be avoided, scanning accuracy and scanning distance can be improved, and the scanning efficiency of the scanning module can be increased.

[0124] In this embodiment, the deflection element can be a micro-electro-mechanical system (MEMS) galvanometer, and the reflector 1213 can be a galvanometer. By using a MEMS galvanometer as the deflection element, high-speed, precise and efficient scanning control capabilities can be achieved, thereby improving the reliability of the scanning module.

[0125] Figure 9 This is another structural schematic diagram of a lidar provided in an embodiment of this application. For example... Figure 9 As shown, the scanning module 1200 of the lidar 1 provided in this application embodiment may further include a scanning control board 1230, which is electrically connected to the deflection element 1210 and / or the motor 1220, for controlling the pitch deflection angle of the deflection element 1210, and / or for controlling the deflection frequency of the deflection element 1210 and the rotation frequency of the motor 1220.

[0126] In the above embodiments, the scanning control board 1230 can be used to control and adjust only the deflection angle of the deflection element 1210 in the vertical direction; or, it can control and adjust the deflection frequency of the deflection element 1210 and the rotation frequency of the motor 1220 at the same time; or, it can control and adjust the deflection angle of the deflection element 1210 in the vertical direction, the deflection frequency of the deflection element 1210 and the rotation frequency of the motor 1220 at the same time.

[0127] The above process can adjust the scanning field of view of the laser beam deflected by the scanning module 1200 to the object under test 2. It can achieve two-dimensional scanning in the horizontal and pitch directions using only the deflection element, motor and scanning control board. While improving the horizontal field of view of the lidar 1, it reduces the complexity and light adjustment difficulty, and can switch different scanning modes according to different usage scenarios.

[0128] Optionally, the pitch deflection scanning field of view of the deflection element 1210 has an angle range of 0° to 60°, meaning that the lidar 1 can cover the object 2 in the vertical direction and scan within an angle range of 0° to 60°. This field of view determines the range of the object 2 that the lidar 1 can detect within a vertical plane. It should be understood that the angle of the pitch scanning field of view for the object 2 can be 0°, 4°, 10°, 18°, 26°, 30°, 40°, 50°, 60°, or any value within the range of 0° to 60°, or exceeding 60°; this application does not impose any limitation on this.

[0129] Optionally, the motor 1220 may be a hollow motor 1220, with a through-center region; wherein, the scanning control board 1230 includes a deflection control board 1231 and a motor control board 1232 respectively disposed on the upper and lower sides of the hollow motor 1220; the deflection control board 1231 is electrically connected to the deflection element 1210, and the motor control board 1232 is electrically connected to the hollow motor 1220.

[0130] The central area of ​​the motor 1220 is open, allowing the integration of wireless optical communication devices to achieve communication between the deflection control board 1231 and the motor control board 1232. This improves the overall integration of the scanning module 1200, reduces mechanical interference, and enhances the reliability of the scanning module. The electrical connection between the motor control board 1232 and the motor 1220 enables more precise control of the deflection elements and the motor, reducing the difficulty of light adjustment.

[0131] In other words, the spatial order of the above structures from top to bottom is: deflection element 1210, deflection control board 1231, motor 1220, and motor control board 1232. The deflection control board 1231 is positioned close to the deflection element 1210 to control the pitch deflection angle and deflection frequency of the deflection element 1210; the motor control board 1232 is positioned close to the motor 1220 to control the rotation frequency of the motor 1220. Based on this, the scanning control board 1230 can control the scanning light field formed by the laser beam in the area of ​​the object under test 2, so as to realize different scanning modes for the object under test 2.

[0132] In some embodiments, the control process of the deflection control board 1231 on the deflection element 1210 can be as follows: the deflection control board 1231 sends a drive signal to the deflection element 1210 to drive the deflection element 1210 to perform pitch deflection; wherein, the deflection control board 1231 modulates the deflection amplitude of the deflection element 1210 by using the deflection angle of the deflection element 1210 obtained by synchronous sampling as a feedback signal, so as to perform closed-loop control on the pitch scanning angle range of the deflection element 1210.

[0133] The above implementation method can reduce interference in the control process, making the pitch scanning range more accurate and stable, and improving the reliability of the scanning module.

[0134] In one embodiment, the deflection control board 1231 may further include a deflection drive circuit and a deflection processor. Specifically, the deflection processor generates a transmission drive signal to the deflection drive circuit to drive the deflection element to vibrate at high frequency through the deflection drive circuit. The transmission drive signal may be a pulse width modulation (PWM) signal. Furthermore, the deflection processor can also adjust the deflection amplitude of the deflection element based on the proportional integral differentiation (PID) algorithm by using the sampled angle signal of the deflection element as a feedback signal, so as to realize closed-loop control of the scanning angle range of the deflection element, which can more flexibly realize the pitch variable scanning mode of the lidar.

[0135] Optionally, the deflection control board 1231 and the motor control board 1232 may each be equipped with a wireless optical communication module to enable bidirectional communication between them. Specifically, by equipping both the deflection control board 1231 and the motor control board 1232 with wireless optical communication modules in the hollow area corresponding to the hollow region of the hollow motor 1220, communication between the motor control board 1232 and the deflection control board 1231 can be achieved using the hollow interior of the hollow motor 1220. This facilitates real-time control of the hollow motor 1220 and the deflection element 1210, enabling precise switching between different scanning modes.

[0136] As an example and not a limitation, the wireless optical communication module in the motor control board 1232 can achieve bidirectional communication between the hollow brushless DC motor 1220 and the top rotating deflection control board 1231; wherein, the downlink optical communication can obtain the scanning angle feedback data of the deflection element 1210, and the uplink optical communication can upload commands to control the vertical scanning angle of the deflection element 1210.

[0137] In some embodiments, the motor control board 1232 may also be provided with a wireless power transmission drive circuit, which can be connected to a wireless power transmission transmitting coil. The wireless power transmission transmitting coil is used to provide power to the deflection control board 1231. The deflection control board 1231 is connected to a wireless power transmission receiving coil, which is used to provide power to the deflection control board 1231 through non-contact electromagnetic coupling with the wireless power transmission transmitting coil.

[0138] By setting up wireless power transmission and receiving coils, power transmission between the deflection control board 1231 and the motor control board 1232 can be achieved without affecting the directional rotation of the deflection control board. This reduces wiring layout, meets the directional rotation requirements of the deflection control board, improves the internal integration of the scanning module 1200, and reduces complexity.

[0139] Optionally, the deflection control board 1231 is also used to acquire the encoder information of the motor 1220. The encoder information includes the rotation frequency and rotation angle of the motor 1220. The deflection control board 1231 can control the deflection frequency of the deflection element 1210 through the acquired encoder information, realize real-time switching and adjustment of different scanning modes, and improve the scene adaptability of the scanning module 1200.

[0140] Furthermore, the deflection control board 1231 can also transmit the real-time scanning angle data of the generator 1220 and the deflection element 1210 to the main control processing board 1300 via downlink optical communication for accurate restoration of the scanning angle of the point cloud.

[0141] In addition to the large amount of heat generated in the transceiver module mentioned above, the motor, wireless transmission and receiving coils in the scanning module of the lidar also generate heat during operation.

[0142] Optionally, the physical distance between the wireless transmission transmitting coil and the wireless transmission receiving coil is less than or equal to 2 mm, and / or, a magnetic shielding sheet is provided on the opposite side of the wireless transmission transmitting coil and / or the wireless transmission receiving coil to isolate the interference of other structural components on the transmission coil, thereby effectively improving the transmission efficiency and reducing ineffective heat loss.

[0143] Specifically, when the distance between the two coils decreases, the transmission efficiency of the magnetic field is improved, which reduces losses during transmission and effectively improves heat dissipation. Furthermore, by placing magnetic shielding sheets on the opposite sides of the upper and lower current-carrying coils, interference from structural components to the magnetic field is isolated, making the magnetic field more concentrated and improving its utilization rate, thereby increasing transmission efficiency.

[0144] Figure 10 This is a partial structural diagram of the motor in the lidar provided in an embodiment of this application. For example... Figure 10 As shown, the motor 1220 includes a stator and a rotor. The stator is fixed by a stator bracket 1221, and the rotor is fixed by a rotor bracket 1222. The dimensions of both the stator bracket 1221 and the rotor bracket 1222 are greater than 40mm. It should be understood that the stator bracket 1221 and the rotor bracket 1222 can be customized and set according to the dimensions of the customized bracket. In some examples, if the dimensions of the stator bracket 1221 and the rotor bracket 1222 are 40mm, then their dimensions can be greater than 40mm to improve the power transmission efficiency. The above values ​​are only examples and do not constitute specific limitations.

[0145] In one embodiment, the stator support 1221 and the rotor support 1222 are metal supports. By increasing the size of the stator support 1221 and the rotor support 1222, the contact area between the support and the motor, the wireless transmission transmitting coil, and the wireless transmission receiving coil is increased. Since metal materials have good thermal conductivity, they can effectively absorb the heat generated by the motor, the wireless transmission transmitting coil, and the wireless transmission receiving coil, and exchange heat with the surrounding environment to effectively dissipate the heat.

[0146] In one embodiment, the deflection control board 1231 can be connected to the deflection element 1210 via a deflection element mounting bracket. The deflection element 1210 and the deflection control board 1231 are fixed on the rotor. The brushless DC motor 1223 is disposed in the stator, with the rotor and stator connected through each other. It is fixed by means of wave springs, snap rings, etc. The wave springs can effectively reduce operating noise by applying preload to the bearings. Optionally, the deflection control board 1231 is a circular circuit board, and the center of the deflection control board 1231 is located on the central axis of the motor 1220.

[0147] Through the above implementation method, during the rotation of the rotatable components in the lidar, the weight of the deflection control plate can be evenly distributed around the central axis, achieving a good dynamic balance effect. At higher rotational speeds, this balanced dynamic balance reduces centrifugal force caused by instability in the center of gravity, thus minimizing mechanical wear.

[0148] Figure 11This is a schematic diagram of the scanning range of a lidar provided in an embodiment of this application. In some embodiments, the scanning mode of the lidar scanning module includes a variable pitch scanning mode; wherein, the scanning module drives the vibration of the fast-axis torsion beam or slow-axis torsion beam of the deflection element through electromagnetic force or electrostatic force, and controls the vibration amplitude by changing the magnitude of the electromagnetic force or electrostatic force to change the pitch deflection angle of the deflection element, that is, to change the pitch field of view (FOV), thereby realizing flexible and variable control of the size of the pitch scanning field of view of the object under test to adapt to the needs of different scanning scenarios. For example, as shown... Figure 11 The three variable pitch scanning field of view angles shown can be: 30° (0°~30°), 40° (-5°~35°), and 60° (-15°~45°).

[0149] With a fixed deflection frequency of the deflection element, the larger the pitch scanning field of view angle, the wider the pitch angle coverage of the scanned space, but the lower the pitch scanning angular resolution. Conversely, reducing the pitch scanning field of view angle will proportionally increase the pitch scanning angular resolution.

[0150] For example, when the pitch scanning field of view is 30°, the pitch scanning angular resolution is doubled compared to when the pitch scanning field of view is 60°. Users can flexibly adjust the pitch scanning field of view according to their needs for the pitch scanning field of view and the pitch scanning angular resolution of the LiDAR scanning scene.

[0151] Figure 12 This is a schematic diagram of the scanning trajectory of the lidar provided in an embodiment of this application, wherein, Figure 12 (a) in this application is a schematic diagram of the repeated scanning trajectory of the lidar provided in the embodiment of this application; Figure 12 (b) in the diagram is a schematic diagram of the encrypted scanning trajectory of the lidar provided in an embodiment of this application. Figure 12 As shown in (a), the scanning mode of the scanning module may also include a repetitive scanning mode, wherein the scanning control board controls the deflection element to deflect in the pitch direction at a first deflection frequency and controls the motor to rotate in the azimuth direction at a first rotation frequency. The first deflection frequency is greater than the first rotation frequency and the first deflection frequency is a positive integer multiple of the first rotation frequency, so as to realize the repetitive scanning mode for scanning the object under test.

[0152] The scanning module uses a scanning control board to modulate the deflection frequency of the deflection element to be higher than the rotation frequency of the motor. When the deflection frequency of the deflection element is a positive integer multiple of the rotation frequency of the motor, a repetitive scanning mode is achieved. The point cloud obtained by the repetitive scanning mode is relatively sparse, which is suitable for scanning in high-speed motion scenarios and can reduce power consumption in scenarios where point cloud angle repeatability is required.

[0153] Optionally, such as Figure 12 As shown in (b), the scanning mode of the scanning module may further include an encrypted scanning mode, wherein the first deflection frequency is a non-positive integer multiple of the first rotation frequency, so as to scan the object under test using the encrypted scanning mode; or, in the encrypted scanning mode, the scanning control board controls the deflection element to deflect in the pitch direction at a second deflection frequency or a third deflection frequency, and controls the motor to rotate in the azimuth direction at a second rotation frequency. Wherein, the second deflection frequency is less than the second rotation frequency, the third deflection frequency is higher than the second rotation frequency, and both the second deflection frequency and the third deflection frequency are non-integer multiples of the second rotation frequency, so as to achieve scanning of the object under test using the encrypted scanning mode.

[0154] When the deflection frequency of the deflection element modulated by the scanning control board is higher or lower than the rotation frequency of the motor, and the deflection frequency of the deflection element is a non-integer multiple of the rotation frequency of the motor, the point cloud angle resolution of the scanning scene is encrypted. The point cloud obtained by the encrypted scanning mode is relatively dense and is suitable for scanning low-speed or stationary scenes to obtain more refined scanning results.

[0155] In some embodiments, the deflection control board generates a frequency control signal based on the code disk information. The frequency control signal is used to adjust the deflection frequency of the deflection element to switch and adjust the scanning module to use a repetitive scanning mode or an encrypted scanning mode for the object under test in real time, thereby improving the scene adaptability of the scanning module.

[0156] In conjunction with the lidar in the above embodiments, in some embodiments, the lidar proposed in this application may also include an optical housing.

[0157] Figure 13 This is another schematic diagram of a lidar structure provided as an embodiment of this application. For example... Figure 13 As shown, the lidar 5 may include a transceiver module 5100, a scanning module 5200, an optical housing 5500, and an extinction region (not shown). The optical housing 5500 protects the lidar components and allows the laser beam emitted by the transceiver module 5100 to pass through and propagate to the object under test 2. It also reflects stray light generated when the laser beam passes through the optical housing to the extinction region located within the lidar 5 via the inner surface of the optical housing. The extinction region is provided with light-absorbing material to eliminate stray light. It should be understood that the structure and function of the transceiver module 5100 and the scanning module 5200 are as described above and will not be repeated here.

[0158] In some embodiments, the optical cover 5500 is an elliptical optical cover with a first focal point A and a second focal point B. The first focal point A is located at the center of the scanning module 5200, and the second focal point B is located in the extinction region. As an example, the inner surface of the optical cover 5500 can reflect stray light generated when the laser beam from the first focal point A located at the center of the scanning module 5200 passes through the optical cover 5500 to the second focal point B located in the extinction region for extinction.

[0159] In the above technical solution, by using a special outer cover shape, the stray light generated when the laser beam passes through the inner surface of the optical outer cover is reflected to a specific extinction area, thereby preventing the stray light generated on the inner surface of the optical outer cover from entering the detector of the transceiver module 5100.

[0160] In some embodiments, the scanning module 5200 includes an effective deflection area and an ineffective deflection area. The effective deflection area is used to deflect the laser beam emitted by the transceiver module 5100 and the laser echo reflected back by the object under test. The ineffective deflection area is provided with an extinction structure to reduce stray light caused by the propagation of the laser beam or laser echo to the ineffective deflection area.

[0161] The above is an introduction to the structure and function of each component of the lidar, illustrated in the structural diagram. The following will introduce the distance measurement principle of the lidar and the error calibration and compensation methods provided in the embodiments of this application.

[0162] Figure 14 This is a schematic diagram illustrating the ranging principle of a lidar provided in an embodiment of this application. The lidar provided in this embodiment of the application determines the distance between the object being measured and the lidar based on the time-of-flight (ToF) principle. The ToF ranging method, also known as the pulse time-of-flight method, typically involves a laser emitter periodically emitting laser pulses (i.e., laser beams) with nanosecond-level pulse widths and sending a timing start signal to the time-to-digital converter module (i.e., the timing circuit in the figure) in the control processor. After being collimated by the transmitting optical system, the laser beam illuminates the object being measured. After being reflected by the target object, an echo signal is formed, i.e., the laser echo reflected back by the object being measured. This echo is sensed by the detector and converted into an echo electrical signal. Then, after passing through the signal amplification circuit and the time discrimination circuit on the detector receiving board, a timing stop signal is formed and sent to the time-to-digital converter module.

[0163] like Figure 15 As shown, the timing discrimination circuit, also known as a comparator, works by comparing the echo signal with the comparator's threshold V. th A comparison is made when the echo signal is greater than the threshold V. th When the echo signal is less than the threshold V, a rising edge is generated. thWhen this occurs, a falling edge is generated, thus forming a square wave-shaped stop signal.

[0164] The time-to-digital converter (TDC) module can calculate the time difference Δt between the start and stop signals, which is the round-trip time difference between the laser beam's emission and reception, also known as the flight time. This flight time can be a part of the timing data and is transmitted to the microprocessor in the main control board for processing. The microprocessor can perform distance resolution processing based on the timing data, that is, determine the measurement distance between the object under test and the lidar according to the flight time Δt. This measurement distance R satisfies the following formula: R = 1 / 2 × c × Δt, where c is the speed of light.

[0165] In the above process, due to factors such as temperature, measurement delay, and device aging, the measured distance obtained by lidar usually has unavoidable errors. The ranging error of lidar can include relative error, absolute error, and temperature drift error. Among them, the relative error, also known as ranging accuracy, is usually determined by the jitter error of the time discrimination circuit, the jitter error of the rising edge, and the measurement error of the time interval. It can be the standard deviation of the measurement results obtained by measuring the object at a certain distance multiple times.

[0166] Constantly identify circuit jitter error σ j The rise time jitter error, which can be determined by the comparator, threshold level ripple, etc., is typically within 2mm. The rise time jitter error is the point at which the comparator acquires the echo signal (beyond the threshold V). th The jitter deviation that exists at the moment of the rise edge can also be called time jitter error; the rise edge jitter error is a statistical time deviation caused by the deformation of the echo signal due to noise. That is, under the influence of noise, the time identification point of the rise edge of the echo signal shifts on the time axis. It is a random error, and the rise edge jitter error σ t The calculation formula can be:

[0167]

[0168] Among them, t r It can be the rise time of the echo signal; SNR can be the signal-to-noise ratio of the echo signal; c is the propagation speed of electromagnetic waves (speed of light).

[0169] Time interval measurement error, namely the measurement accuracy error of time interval Δt, is a non-linear error. The time interval measurement of LiDAR is usually based on the configuration and data acquisition of TDC by the control processor, and the time measurement is performed by using the internal calibration of TDC chip and uniform delay line; however, the interval of delay line will produce time interval measurement error, resulting in non-linear error in the measurement result of LiDAR.

[0170] In the ranging process of lidar, the measured value can be any data in the synchronization clock cycle, and each value has an equal probability of occurrence. Therefore, the formula for calculating the time interval measurement error can be:

[0171]

[0172] Where, Δt TDC It can be the TDC timing resolution in the control processor, which is related to the model of the control processor chip used, and is approximately within 50ps.

[0173] Since both the start and stop signals introduce time interval measurement errors during the ranging process, the overall time interval measurement error can be expressed as:

[0174]

[0175] The three errors mentioned above are independent of each other; therefore, the total relative error σ of the lidar is... c The calculation formula can be:

[0176]

[0177] Absolute error, also known as ranging accuracy, typically includes fixed delay error and walk error. It can be the average of the difference between the measurement result of the object being measured and the actual distance between the lidar and the object being measured. Fixed delay error can be a systematic error caused by wiring delay, device delay, etc., and is usually a fixed value. Walk error can be a time deviation caused by changes in the amplitude and waveform of the echo signal, which causes the echo signal to drift when it crosses the threshold during the time discrimination process.

[0178] Figure 16 This is a schematic diagram illustrating the principle of walking error. The horizontal axis represents time, and the vertical axis represents the amplitude of the echo signal. For example... Figure 16 As shown, when the dynamic range of the distance to the object being measured is large or the reflectivity of different points on the object varies greatly, the amplitude and waveform of the received echo signal will change significantly, manifesting as strong and weak echo signals. That is, the dynamic range of the echo signal is reflected in the different intensities of the echo signals formed by diffuse reflection from the object being measured. Echo signals with different amplitudes pass through the threshold V of the time discrimination circuit. th The time deviation Δt is formed at different times. we This represents the walking error.

[0179] Temperature drift error can be a ranging error caused by parameter changes due to temperature variations inside the lidar. For example, when the temperature inside the lidar changes, the detector gain usually changes accordingly, which in turn causes ranging error. Or, when the detector gain is stable, the delay of the laser emitter or detector device inside the lidar changes with temperature, which in turn causes ranging error.

[0180] Ranging errors in lidar can lead to a decrease in the detection accuracy of the measured object, affecting lidar performance. Therefore, embodiments of this application provide an error calibration method and a compensation method for lidar, which can improve the accuracy of lidar error calibration and ranging.

[0181] Figure 17 This is a schematic flowchart illustrating an error calibration method provided in an embodiment of this application. The lidar has a built-in calibration structure and a deflection element. The calibration structure is located within the lidar's non-detection zone in the azimuth direction. The range of the lidar's non-detection zone in the azimuth direction can be within a range of 270° to 360° that it cannot cover in the azimuth direction. The method includes steps S1701 to S1703.

[0182] S1701, obtain the actual distance between the calibration structure and the deflection element.

[0183] S1702 controls the deflection element to rotate to the calibration structure in the non-detection area of ​​the lidar in the azimuth direction, and drives the transceiver module to emit a laser beam to be deflected by the deflection element to the calibration structure for scanning and receiving the first echo signal reflected back by the calibration structure, and then obtains the measurement distance between the calibration structure and the deflection element based on the first echo signal.

[0184] S1703 uses the measured distance and the actual distance to determine the first ranging error of the lidar.

[0185] The first ranging error can be the temperature drift ranging error of the lidar. Through the above implementation method, the lidar can obtain the first ranging error at the current temperature after scanning one circle in the azimuth direction, and thus obtain the first ranging error in the entire temperature range, improving the calibration accuracy of the lidar's ranging error. In addition, the calibration structure is built into the lidar and located in its non-detection area in the azimuth direction, which can improve the utilization rate of the lidar's internal space.

[0186] Return to reference Figure 3 The calibration structure is mounted on the receiving mounting bracket 1124. The calibration structure is provided with a calibration target 1125. The distance between each point on the surface of the calibration target facing the deflection element and the center of the deflection element is equal. S1701 may include: determining the distance between the point on the surface and the center of the deflection element as the actual distance.

[0187] Optionally, the surface of the calibration target 1125 facing the deflection element can be a spherical surface, and the center of the deflection element can be the center of the sphere corresponding to the spherical surface. The actual distance between the deflection element and the calibration target, i.e. the physical distance between them, is the radius corresponding to the spherical surface. This actual distance can be a pre-set known distance, which can be measured by a measuring ruler or other measuring equipment before leaving the factory. This application does not limit the method of obtaining this actual distance.

[0188] Optionally, S1702 may include: receiving a first echo signal reflected back when the deflection element scans the laser beam onto the calibration target, and determining the measurement distance based on the first echo signal; wherein the first echo signal may be a laser echo reflected back from the surface of the calibration target, the laser echo may be emitted by a laser emitter in the emission optics system of the lidar, and deflected to the surface by the deflection element, and after being reflected by the surface of the calibration target, the first echo signal is formed for reception by the detector.

[0189] The microprocessor in the lidar can process the first echo signal based on the Time-of-Flight (ToF) ranging method to obtain the measured distance between the deflection element and the calibration structure. Optionally, determining the measured distance based on the first echo signal includes: determining multiple first measured distances based on multiple first echo sub-signals included in the first echo signal, wherein the multiple first echo sub-signals are signals reflected back from different points on the calibration target surface by the deflection element scanning the laser beam, and the multiple first measured distances are distances determined based on each first echo sub-signal; and determining the average value of the multiple first measured distances as the measured distance. It should be understood that the point on the surface of the calibration target used for ranging is located on the scanning path of the lidar, and the number of first measured distances is related to the deflection frequency of the lidar's deflection element and the rotation frequency of the motor.

[0190] By measuring multiple points on the surface of the calibration target to obtain multiple first measurement distances, and taking the average of these multiple first measurement distances as the measurement distance, a more accurate first ranging error can be obtained, thereby further improving the calibration accuracy of the ranging error of the lidar.

[0191] In S1703, the first measurement error can be the difference between the measured distance and the actual distance between the deflection element and the calibration structure. After obtaining the first measurement error, during the actual measurement of the object using the lidar, the first measurement error can be used to compensate for the measured distance of the object to be measured in order to calibrate the ranging error of the lidar and improve the ranging accuracy.

[0192] Figure 18 This is a schematic flowchart illustrating another error calibration method provided in an embodiment of this application. The method may include steps S1801 to S1805.

[0193] S1801 obtains the detector temperature of the lidar through a temperature sensor placed near the detector.

[0194] S1802 adjusts the detector's bias voltage according to the detector temperature to keep the detector's gain constant.

[0195] S1803, obtain the actual distance between the calibration structure and the deflection element.

[0196] S1804 controls the deflection element to rotate to the calibration structure in the non-detection area of ​​the lidar in the azimuth direction, and drives the transceiver module to emit a laser beam to be deflected by the deflection element to the calibration structure for scanning and to receive the echo signal reflected back by the calibration structure. Then, the measurement distance between the calibration structure and the deflection element is obtained based on the echo signal.

[0197] S1805 determines the first ranging error of the lidar using the actual distance and the measured distance.

[0198] In S1802, the relationship model or mapping table between detector temperature, bias voltage and gain can be established in advance. After obtaining the detector temperature, the voltage value to be adjusted can be obtained by using the relationship model or mapping table to achieve bias voltage regulation so that the detector gain is fixed. Alternatively, other detector gain control methods can be selected according to the actual application scenario and requirements. In S1803 to S1805, the method for determining the first ranging error can be referred to the relevant content above. For the sake of brevity, it will not be repeated here.

[0199] The above implementation method helps to reduce or even avoid the influence of temperature changes on the detector gain, making the calibration of the first ranging error more accurate, and further improving the calibration accuracy of the ranging error of the lidar.

[0200] Figure 19 This is a schematic flowchart illustrating an error compensation method provided in an embodiment of this application. The method may include steps S1901 to S1903.

[0201] S1901 controls the transceiver module in the lidar to emit a beam of light to the object under test and to receive the second echo signal reflected back from the object under test, so as to obtain the calibration parameter value and measurement distance corresponding to the second echo signal.

[0202] The second echo signal can be a laser echo reflected back by the object under test. The laser beam can be emitted by the laser transmitter in the transceiver module of the lidar and deflected to the object under test by the deflection element, then reflected by the object under test and received by the detector in the transceiver module.

[0203] S1902, determine the walking error value corresponding to the calibration parameter value based on the preset mapping relationship table, wherein the preset mapping relationship table is a lookup table constructed based on the calibration parameter and the walking error.

[0204] S1903 uses the walking error value to calibrate the measurement distance and obtain the true distance of the object being measured.

[0205] By implementing the above methods, the walking error of the lidar is calibrated, thereby further improving the ranging accuracy of the lidar.

[0206] Optionally, the preset mapping table is pre-constructed, and its construction method includes: obtaining the values ​​of calibration parameters and corresponding walking error values ​​within the full dynamic range of the second echo signal, where the calibration parameters are any one or more combinations of the peak value, energy, and pulse width of the second echo signal; and constructing a lookup table based on the mapping relationship between the calibration parameters and the walking error to obtain the preset mapping table. It should be understood that the full dynamic range of the echo signal refers to the range of the echo signal from the minimum detectable signal strength to the maximum processable signal strength.

[0207] This application does not limit the method of obtaining calibration parameters. Different methods can be adopted according to the characteristics of different calibration parameters. For example, the peak value of the second echo signal can be obtained by designing a peak hold circuit. Another example is that the energy of the second echo signal can be obtained by designing an energy hold circuit. Yet another example is that the pulse width of the second echo signal can be obtained by measuring the time difference between its rising and falling edges using a TDC.

[0208] Through the above implementation method, a mapping table of calibration parameters and walking error within the full dynamic range of the second echo signal when the lidar is working normally can be obtained. Thus, by looking up the table, the corresponding current walking error value can be obtained based on the current calibration parameter value of the lidar to complete the calibration of the measurement distance, thereby improving the ranging accuracy.

[0209] It should be understood that Figure 19 The illustrated solution process is merely one feasible implementation of the method proposed in this application. In some embodiments, Figure 19 The methods and steps in the text can also be compared with... Figure 17 or Figure 18 In combination with the method steps shown in other embodiments, different ranging errors are obtained and used together for error compensation of the lidar to improve the ranging accuracy of the lidar.

[0210] Optionally, the error compensation method proposed in this application may further include: obtaining the ranging error of the lidar, which includes temperature drift ranging error and / or walking error value; calibrating the measurement distance of the object to be measured based on the ranging error; through the above implementation, the ranging performance of the lidar proposed in this application can be improved, and the ranging accuracy can reach within ±30mm.

[0211] Optionally, the ranging error may also include at least one of the following: time discrimination circuit jitter error, rising edge jitter error, time interval measurement error, or fixed delay error; through the above embodiments, the ranging performance of the lidar proposed in this application can be further improved, and the ranging accuracy for 90% of target boards within a 35m range indoors can reach within 20mm, and the ranging accuracy within a 45m range can reach ±30mm.

[0212] In the embodiments of this application, the terms "first," "second," and various numerical designations (e.g., "1," "2," etc.) are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the process numbers above does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. It should be understood that the objects described in this way can be interchanged where appropriate so as to describe solutions other than those in the embodiments of this application.

[0213] This application also provides an apparatus for calibrating a lidar, including a processor and a memory. The memory is coupled to the processor and is used to store computer programs or instructions. The processor is used to execute the computer programs or instructions in the memory, causing the apparatus to perform the lidar calibration methods in the above-described method embodiments.

[0214] This application also provides a computer-readable storage medium storing a computer program or instructions thereon, which, when executed on a computer, causes the computer to perform the calibration method for lidar in the above-described method embodiments.

[0215] This application also provides a chip system, including a processor, for calling and running a computer program from a memory, so that a lidar equipped with the chip system performs the lidar calibration method in the above-described method embodiments.

[0216] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0217] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0218] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0219] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0220] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0221] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A scanning module, characterized by The scanning module is applied to a laser radar comprising a transmitting optical system and a receiving optical system; wherein the scanning module comprises: a deflection element, configured to receive a laser beam transmitted by the transmitting optical system, and to pitch the laser beam to a measured object to perform a pitch scanning on the measured object; a motor, configured to support and drive the deflection element to rotate in an azimuth direction, and to azimuth deflect the laser beam to the measured object to perform an azimuth scanning on the measured object; the deflection element is further configured to receive a laser echo reflected by the measured object, and to deflect the laser echo to the receiving optical system; a scanning control board, electrically connected with the deflection element and / or the motor, configured to control a pitch deflection angle of the deflection element, and / or to control a deflection frequency of the deflection element and a rotation frequency of the motor.

2. The scanning module of claim 1, wherein, the deflection element comprises a fast-axis torsional beam, a slow-axis torsional beam and a retroreflector; the deflection element pitches the laser beam to the measured object by rotating the fast-axis torsional beam or the slow-axis torsional beam.

3. The scanning module of claim 2, wherein, an angle range of a pitch scanning field of view of the deflection element is 0°-60°, and an angle range of an azimuth scanning field of view of the deflection element driven by the motor is 0°-270°.

4. The scanning module of claim 2, wherein, a size of the retroreflector is greater than a size of the laser beam or the laser echo.

5. The scanning module of any one of claims 2 to 4, wherein, the scanning mode of the scanning module comprises a variable pitch scanning mode, wherein the scanning module drives a vibration amplitude of the fast-axis torsional beam or the slow-axis torsional beam of the deflection element by electromagnetic force or electrostatic force, changes a pitch deflection angle of the deflection element, and scans the measured object by the variable pitch scanning mode.

6. The scanning module of claim 5, wherein, the scanning mode further comprises a repeated scanning mode, wherein the scanning control board controls the deflection element to pitch in a first deflection frequency, and controls the motor to rotate in a first rotation frequency, the first deflection frequency is greater than the first rotation frequency, and the first deflection frequency is a positive integer multiple of the first rotation frequency, so as to scan the measured object by the repeated scanning mode.

7. The scanning module of claim 6, wherein, the scanning mode comprises an encrypted scanning mode, wherein the first deflection frequency is a non-positive integer multiple of the first rotation frequency, so as to scan the measured object by the encrypted scanning mode.

8. The scanning module of claim 5, wherein, the scanning mode comprises an encrypted scanning mode, wherein the scanning control board controls the deflection element to pitch in a second deflection frequency or a third deflection frequency, and controls the motor to rotate in a second rotation frequency, the second deflection frequency is less than the second rotation frequency, the third deflection frequency is higher than the second rotation frequency, and the second deflection frequency or the third deflection frequency is a non-integer multiple of the second rotation frequency, so as to scan the measured object by the encrypted scanning mode.

9. The scanning module of any one of claims 1 to 4, wherein, the motor is a hollow motor, and a central region of the hollow motor is through. The scanning control board comprises a deflection control board and a motor control board arranged on the upper and lower sides of the hollow motor respectively. The deflection control board is electrically connected with the deflection element, and the motor control board is electrically connected with the hollow motor.

10. The scanning module of claim 9, wherein, Wireless optical communication modules are arranged on the deflection control board and the motor control board respectively, so that bidirectional communication is realized between the deflection control board and the motor control board.

11. The scanning module of claim 9, wherein, The motor control board further comprises a wireless power transmission driving circuit connected with a wireless power transmission transmitting coil, which is used to provide power for the deflection control board. The deflection control board is connected with a wireless power transmission receiving coil, which is coupled with the wireless power transmission transmitting coil through non-contact electromagnetic coupling to provide power for the deflection control board.

12. The scanning module of claim 11, wherein, The deflection control board transmits a driving signal to the deflection element to drive the deflection element to deflect in the pitch direction. The deflection control board modulates the deflection amplitude of the deflection element by taking the deflection angle of the deflection element obtained by synchronous sampling as a feedback signal, so as to realize closed-loop control of the pitch scanning range of the deflection element.

13. The scanning module of claim 9, wherein, The deflection control board is further used to acquire code disc information of the motor, which comprises the rotation frequency and rotation angle of the motor. The deflection control board generates a frequency control signal according to the code disc information, which is used to adjust the deflection frequency of the deflection element to switch the scanning mode of the scanning module to the repeated scanning mode or the encrypted scanning mode.

14. A lidar, comprising: The scanning module comprises: The scanning module according to any one of claims 1 to 13; and a transceiving module comprising a transmitting optical system for transmitting a laser beam to a measured object and a receiving optical system for receiving a laser echo reflected by the measured object.

15. The lidar of claim 14, wherein, The transceiving module further comprises a light guide prism, wherein: The transmitting optical system is used to transmit the collimated and compressed laser beam to the light guide prism to transmit the laser beam to the scanning module through the light guide prism; The scanning module is used to deflect the laser beam to the measured object; The receiving optical system is used to receive the laser echo reflected by the measured object and deflected by the scanning module; The transmitting optical system, the light guide prism and the scanning module are arranged from top to bottom, and the centers of the transmitting optical system, the light guide prism and the scanning module are located on the same straight line.

16. The lidar of claim 15, wherein, The transceiving module further comprises a hollow mirror, and the light guide prism penetrates through the hollow mirror, which is used to reflect the laser echo reflected by the measured object and deflected by the scanning module to the receiving optical system.

17. The lidar of any one of claims 14-16, wherein, The laser radar further comprises a main control processing board and a transceiving control board; The main control processing board controls the scanning control board to control the scanning module to switch the scanning mode; The transceiving control board controls the transmitting optical system to transmit the laser beam and controls the receiving optical system to receive the laser echo reflected by the measured object.

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