Laser control method, calibration method, device and laser radar based on galvanometer

Abstract

The present application relates to a laser synchronization control method, calibration method, device and laser radar based on a galvanometer. The laser synchronization control method based on a galvanometer includes: obtaining a fast-axis feedback signal when the galvanometer is scanning; obtaining a first phase difference between a fast-axis drive signal and the fast-axis feedback signal, and obtaining a second phase difference between the laser emission period and the fast-axis drive signal; setting the phase of the fast-axis drive signal according to the first phase difference and the second phase difference, so that the laser emitted at the set point is aligned in a preset direction. The solution provided in the present application can better realize the synchronous control of laser emission and galvanometer fast-axis movement.

Description

Technical Field

[0001] The present application relates to the field of laser radar technology, and in particular to a laser synchronization control method based on a galvanometer, a laser synchronization calibration method, a device and a laser radar. Background Art

[0002] At present, the development direction of LiDAR is shifting from rotating LiDAR to solid-state LiDAR. The main technologies used in solid-state LiDAR include phased array, 3D Flash or MEMS (Micro-Electro-Mechanical System). Among them, LiDAR system based on MEMS is easier to implement technically, with better effect and lower cost.

[0003] For solid-state LiDAR based on micro-electromechanical systems, the key components of solid-state LiDAR include electromagnetic galvanometers (galvanometers for short). The main working principle of the galvanometer is to combine horizontal scanning and vertical scanning into two-dimensional scanning. When the laser is emitted to the working galvanometer, the galvanometer reflects the laser and shoots it to each position of the entire frame, scanning a two-dimensional field of view. The two scanning directions of the galvanometer correspond to the fast axis direction and the slow axis direction respectively, and the fast axis drive signal drives the galvanometer to perform resonant motion in the fast axis direction.

[0004] When the laser is deflected by the galvanometer and then emitted, the laser emission cycle needs to be coordinated with the fast axis movement of the galvanometer, otherwise the spatial coordinates of the point cloud will be misaligned in the preset direction. However, due to various reasons, it is difficult to achieve a good synchronization control of laser emission and galvanometer fast axis movement. Summary of the invention

[0005] In order to solve or partially solve the problems existing in the related art, the present application provides a laser synchronization control method, device and laser radar based on a galvanometer, which can better realize the synchronous control of the laser emission cycle and the fast axis movement of the galvanometer.

[0006] The first aspect of the present application provides a laser synchronization control method based on a galvanometer, comprising:

[0007] Obtain the fast axis feedback signal when the galvanometer is scanning;

[0008] acquiring a first phase difference between the fast axis drive signal and the fast axis feedback signal, and

[0009] Acquiring a second phase difference between the emission period of the laser and the fast axis driving signal;

[0010] The phase of the fast-axis driving signal is set according to the first phase difference and the second phase difference, so that the laser emitted at a set point is aligned in a preset direction.

[0011] In one embodiment, the obtaining of a first phase difference between the fast axis drive signal and the fast axis feedback signal, and the obtaining of a second phase difference between the emission period of the laser and the fast axis drive signal, include:

[0012] adjusting the frequency of the fast-axis drive signal, and taking the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value as a first phase difference;

[0013] The phase of the emission period of the laser is adjusted, and when the laser is aligned at a preset point, the phase difference between the emission period of the laser and the fast axis driving signal is obtained as a second phase difference.

[0014] In one embodiment, the obtaining of a first phase difference between the fast axis drive signal and the fast axis feedback signal, and the obtaining of a second phase difference between the emission period of the laser and the fast axis drive signal, include:

[0015] Acquiring a second phase difference between an emission period of the laser and the fast axis driving signal, which is set to a preset value;

[0016] The frequency of the fast-axis driving signal is adjusted, and when the laser is aligned at a preset point, a phase difference between the fast-axis driving signal and the fast-axis feedback signal is obtained as a first phase difference.

[0017] In one embodiment, the phase setting of the fast axis drive signal according to the first phase difference and the second phase difference includes:

[0018] Phase-locking the fast-axis drive signal and the fast-axis feedback signal according to the first phase difference;

[0019] The emission period of the laser and the fast axis driving signal are phase-fixed according to the second phase difference.

[0020] In one embodiment, the phase of the fast axis drive signal is set according to the first phase difference and the second phase difference so that the laser emitted at a set point is aligned in a preset direction, including:

[0021] The phase of the fast-axis driving signal is set according to the first phase difference and the second phase difference, so that the emitted laser light is aligned in the vertical direction when passing through the same set point in a fast-axis period.

[0022] In one embodiment, the method further comprises:

[0023] When the maximum deflection angle of the galvanometer is the rated angle, the reference amplitude of the fast-axis feedback signal is obtained, and the amplitude of the fast-axis drive signal is adjusted in a closed loop so that the feedback amplitude of the fast-axis feedback signal of the galvanometer reaches the reference amplitude.

[0024] A second aspect of the present application provides a laser synchronization control device based on a galvanometer, comprising:

[0025] A signal acquisition module is used to obtain a fast axis feedback signal when the galvanometer is scanning;

[0026] A phase difference module is used to obtain a first phase difference between the fast axis drive signal and the fast axis feedback signal,

[0027] and obtaining a second phase difference between the laser emission period and the fast axis driving signal;

[0028] The phase processing module is used to set the phase of the fast axis drive signal according to the first phase difference and the second phase difference obtained by the phase difference module, so that the laser emitted at the set point is aligned in a preset direction.

[0029] In one embodiment, the phase difference module includes:

[0030] A first phase difference module, used for adjusting the frequency of the fast-axis drive signal, and taking the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value as a first phase difference;

[0031] The second phase difference module is used to adjust the phase of the laser emission period, and when the laser is aligned at a preset point, obtain the phase difference between the laser emission period and the fast axis drive signal as the second phase difference.

[0032] In one embodiment, the phase difference module includes:

[0033] A second phase difference module, used to obtain a second phase difference between the emission period of the laser and the fast axis drive signal, which is set to a preset value;

[0034] The first phase difference module is used to adjust the frequency of the fast-axis drive signal, and when the laser is aligned at a preset point, obtain the phase difference between the fast-axis drive signal and the fast-axis feedback signal as the first phase difference.

[0035] The third aspect of the present application provides a laser synchronous calibration method based on a galvanometer, comprising:

[0036] Obtain the fast axis feedback signal when the galvanometer is scanning;

[0037] Determine a first phase difference between a fast-axis drive signal and the fast-axis feedback signal, and determine a second phase difference between an emission period of the laser and the fast-axis drive signal;

[0038] The first phase difference and the second phase difference are output.

[0039] In one embodiment, the determining of a first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and the determining of a second phase difference between the emission period of the laser and the fast-axis drive signal, comprises:

[0040] adjusting the frequency of the fast-axis drive signal, and taking the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value as a first phase difference;

[0041] The phase of the emission period of the laser is adjusted, and when the laser is aligned at a preset point, the phase difference between the emission period of the laser and the fast axis driving signal is determined as a second phase difference.

[0042] In one embodiment, the determining of a first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and the determining of a second phase difference between the emission period of the laser and the fast-axis drive signal, comprises:

[0043] Determine that a second phase difference between an emission period of the laser and the fast axis drive signal is a preset value;

[0044] The frequency of the fast-axis driving signal is adjusted, and when the laser is aligned at a preset point, a phase difference between the fast-axis driving signal and the fast-axis feedback signal is determined as a first phase difference.

[0045] A fourth aspect of the present application provides a laser radar, comprising the galvanometer-based laser synchronization control device as described above.

[0046] The technical solution provided by this application includes the following beneficial effects:

[0047] The technical solution provided by the present application, after obtaining the first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and obtaining the second phase difference between the laser emission cycle and the fast-axis drive signal, the phase of the fast-axis drive signal is set according to the first phase difference and the second phase difference, so that the laser emitted at the set point is aligned in a preset direction. Through the above processing, the phase difference between the fast-axis drive signal and the fast-axis feedback signal is locked, and the phase difference between the laser emission cycle and the fast-axis drive signal of the galvanometer is locked, so that the laser emitted at the set point is aligned in a preset direction, and the laser emission cycle is coordinated with the fast-axis movement, thereby better realizing the synchronous control of the laser emission cycle and the fast-axis movement of the galvanometer.

[0048] Furthermore, the present application can obtain the amplitude of the fast-axis feedback signal of the galvanometer as the reference amplitude when the maximum deflection angle of the galvanometer is the rated angle, and adjust the amplitude of the fast-axis drive signal in a closed loop so that the feedback amplitude of the fast-axis feedback signal of the galvanometer reaches the reference amplitude. Through the above processing, the fast-axis motion amplitude of the galvanometer is prevented from being affected by the change of air pressure, and the real-time air pressure adaptability is achieved during the operation of the galvanometer.

[0049] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and other objects, features and advantages of the present application will become more apparent by describing in more detail exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0051] Figure 1 is a schematic diagram of the structure of a laser radar provided in an embodiment of the present application;

[0052] Figure 2 It is a structural schematic diagram of a MEMS galvanometer provided in an embodiment of the present application;

[0053] Figure 3 is a flow chart of a laser synchronization control method based on a galvanometer according to an embodiment of the present application;

[0054] Figure 4 is a flow chart of a laser synchronization control method based on a galvanometer according to another embodiment of the present application;

[0055] Figure 5 is a schematic diagram of phase-locking processing in a galvanometer-based laser synchronization control method according to an embodiment of the present application;

[0056] Figure 6 It is a schematic diagram of closed-loop adjustment of the amplitude of the fast-axis drive signal of the galvanometer in the galvanometer-based laser synchronization control method of an embodiment of the present application;

[0057] Figure 7 is a schematic structural diagram of a galvanometer-based laser synchronization control device according to an embodiment of the present application;

[0058] Figure 8 is a schematic structural diagram of a laser synchronization control device based on a galvanometer according to another embodiment of the present application;

[0059] Fig. 9 is a flow chart of a laser synchronous calibration method based on a galvanometer provided in another embodiment of the present application;

[0060] Fig.10is a schematic diagram comparing the implementation of laser alignment and the implementation of laser alignment not implemented in the embodiment of the present application; Fig.11 It is a structural schematic diagram of a galvanometer-based laser synchronous calibration device provided in an embodiment of the present application;

[0061] Fig.12 is a schematic diagram of the structure of the laser radar provided in an embodiment of the present application;

[0062] Fig.13 This is a schematic diagram of the structure of a laser radar provided in another embodiment of the present application.

[0063] Fig.14 It is a schematic diagram of the structure of a laser radar provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0064] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0065] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0066] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0067] In the related art, it is not possible to achieve the synchronous control of laser emission and the fast axis motion of the galvanometer. The present application provides a laser synchronous control method based on a galvanometer, which can achieve the synchronous control of laser emission and the fast axis motion of the galvanometer.

[0068] The technical solution of the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0069] Please refer to Figure 1 , Figure 1 The schematic diagram of the structure of a laser radar provided in an embodiment of the present application is exemplarily shown. Figure 1 As shown, the laser radar may include: a laser emitter 110, a galvanometer 120, and a controller 130. Among them: the laser emitter 110 is used to emit laser S. The galvanometer 120 is used to receive and deflect the laser S emitted by the laser emitter 110 to change the emission angle of the laser S to achieve scanning. The controller 130 is connected to the laser emitter 110 and the galvanometer 120, and is used to send an emission drive signal to control the laser emitter 110 to emit laser S, and send a galvanometer drive signal to control the movement of the galvanometer 120. The galvanometer 120 may be a MEMS galvanometer. Next, Figure 2 ,introduce Figure 1 The structure of the laser radar when the galvanometer 120 is a MEMS galvanometer. Figure 2 , Figure 2 The structural diagram of a MEMS galvanometer provided in an embodiment of the present application is exemplarily shown. Figure 2 As shown, the MEMS oscillator may include: a base 210, a coil frame 220, a lens 230, a fast axis 240, a slow axis 250 and an external magnetic field 260. Wherein:

[0070] The base 210 is used to fix and install the entire galvanometer structure, and the middle part is a hollow part for accommodating moving parts. The lens 230 is used to reflect the laser S; at the same time, the lens 230 can also drive the laser S to scan various positions in the field of view (frame) by twisting along the fast axis and the slow axis. When the fast axis and the slow axis are perpendicular to each other and the slow axis of the MEMS galvanometer is placed in the horizontal direction, the MEMS galvanometer deflects along the fast axis to achieve scanning in the pitch direction, and the MEMS galvanometer deflects along the slow axis to achieve scanning in the horizontal direction.

[0071] The left and right sides of the coil frame 220 can be connected to the base 210 by setting a slow axis 250, and the upper and lower sides of the coil frame 220 can be connected to the lens 230 by setting a fast axis 240. The lens 230 is twisted around the fast axis 240, and the coil frame 220 is twisted around the slow axis 250. Under the combined action of the electromagnetic force generated by the coil frame 220 and the external magnetic field 260, the lens 230 is moved in two directions.

[0072] Figure 3 It is a flow chart of the galvanometer-based laser synchronization control method of an embodiment of the present application.

[0073] See also Figure 3 , the method comprising:

[0074] S301, obtaining a fast axis feedback signal when the galvanometer performs scanning.

[0075] When the galvanometer is scanning, a fast-axis feedback signal of the galvanometer when scanning can be obtained. The galvanometer in the embodiment of the present application may be a galvanometer of a laser radar but is not limited thereto, and may also be a galvanometer in related equipment in other application scenarios. Among them, the drive signal drives the galvanometer to perform fast-axis motion and slow-axis motion. The fast-axis drive signal adopts a sinusoidal drive signal to make the galvanometer in a resonant motion state in the fast-axis direction. The slow-axis drive signal adopts a sawtooth wave drive to make the galvanometer move at a uniform speed in the slow-axis direction. The fast-axis drive signal and the slow-axis drive signal are superimposed as a drive signal, and the drive signal is used to drive the galvanometer to move in two directions. A position feedback device may be provided on the galvanometer, and the position feedback device outputs a feedback signal to the outside, and the feedback signal includes a fast-axis feedback signal and a slow-axis feedback signal. The position feedback device may be a displacement sensor arranged on the fast axis and the slow axis.

[0076] S302 , obtaining a first phase difference between a fast-axis driving signal and a fast-axis feedback signal, and obtaining a second phase difference between an emission period of the laser and the fast-axis driving signal.

[0077] One method may be to adjust the frequency of the fast-axis drive signal, and use the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value as the first phase difference; and adjust the phase of the laser emission period, and when the laser is aligned in a preset direction, use the phase difference between the laser emission period and the fast-axis drive signal as the second phase difference.

[0078] That is to say, the first phase difference can be the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the fast-axis motion is in a resonant state. The fast-axis drive signal with a fixed amplitude is used to drive the galvanometer to move and obtain the fast-axis feedback signal. The phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches the maximum value is the first phase difference between the fast-axis drive signal and the fast-axis feedback signal. The first phase difference between the fast-axis drive signal and the fast-axis feedback signal is fixed, and the phase of the laser emission cycle is adjusted. When the laser is aligned at a preset point, the phase difference between the laser emission cycle and the fast-axis drive signal is the second phase difference.

[0079] Another method may be to obtain a second phase difference between the emission period of the laser and the fast-axis drive signal, which is set to a preset value; adjust the frequency of the fast-axis drive signal, and when the laser is aligned in a preset direction, the phase difference between the fast-axis drive signal and the fast-axis feedback signal is used as the first phase difference. In other words, the second phase difference between the emission period of the laser and the fast-axis drive signal may be set to a preset value. The second phase difference between the emission period of the laser and the fast-axis drive signal is fixed, and the frequency of the fast-axis drive signal is adjusted so that the phase difference between the fast-axis drive signal and the fast-axis feedback signal is adjusted. When the laser is aligned at a preset point, the phase difference between the fast-axis drive signal and the fast-axis feedback signal is obtained as the first phase difference.

[0080] S303 , setting the phase of the fast-axis driving signal according to the first phase difference and the second phase difference, so that the laser emitted at the set point is aligned in a preset direction.

[0081] The fast axis drive signal and the fast axis feedback signal can be phase-locked according to the first phase difference; and the laser emission period and the fast axis drive signal can be phase-fixed according to the second phase difference.

[0082] The phase of the fast axis driving signal can be set according to the first phase difference and the second phase difference, so that the emitted laser light is aligned in the vertical direction when passing through the same set point in a fast axis period.

[0083] The technical solution provided by the present application, after obtaining the first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and obtaining the second phase difference between the laser emission cycle and the fast-axis drive signal, the phase of the fast-axis drive signal is set according to the first phase difference and the second phase difference, so that the laser emitted at the set point is aligned in a preset direction. Through the above processing, the phase difference between the fast-axis drive signal and the fast-axis feedback signal is locked, and the phase difference between the laser emission cycle and the fast-axis drive signal of the galvanometer is locked, so that the laser emitted at the set point is aligned in a preset direction, and the laser emission cycle is coordinated with the fast-axis movement, thereby better realizing the synchronous control of the laser emission cycle and the fast-axis movement of the galvanometer.

[0084] Figure 4 It is a flow chart of a laser synchronization control method based on a galvanometer according to another embodiment of the present application. The laser radar according to the embodiment of the present application can calibrate the phase difference during operation, calibrate the first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and calibrate the second phase difference between the laser emission period and the fast-axis drive signal.

[0085] See also Figure 4 , the method comprising:

[0086] S401, driving the galvanometer to scan.

[0087] The galvanometer in the embodiment of the present application may be the galvanometer of the laser radar provided in the above embodiment but is not limited thereto, and may also be the galvanometer in related equipment in other application scenarios. The drive signal sent by the drive module can drive the galvanometer movement to achieve scanning. The fast-axis drive signal and the slow-axis drive signal are superimposed as a drive signal. The fast-axis drive signal may adopt a sinusoidal drive signal to make the galvanometer in a resonant motion state in the fast-axis direction. The slow-axis drive signal may adopt a sawtooth wave drive to make the galvanometer perform non-resonant uniform motion in the slow-axis direction. When the laser radar is in working state, the fast-axis motion is used for horizontal reciprocating line scanning, and the slow-axis motion is used for up and down reciprocating frame scanning. In addition, the direction may also be reversed, the line scan may also be an up and down reciprocating line scan, and the frame scan may be a horizontal reciprocating scan, which is specifically related to the setting position of the laser radar.

[0088] The galvanometer of the present application may be a micro-electro-mechanical system galvanometer (MEMS galvanometer). In the present application, the MEMS galvanometer may be a one-dimensional MEMS galvanometer or a two-dimensional MEMS galvanometer. A one-dimensional MEMS galvanometer is a MEMS galvanometer that can change the direction of the light path in one direction, and a two-dimensional MEMS galvanometer is a MEMS galvanometer that can change the direction of the light path in two directions.

[0089] S402, obtaining a fast-axis feedback signal when the galvanometer performs scanning.

[0090] When the laser radar is turned on and the galvanometer is scanning, a fast-axis feedback signal of the galvanometer scanning can be obtained.

[0091] The galvanometer may be provided with a position feedback device, which outputs a feedback signal, including a fast axis feedback signal and a slow axis feedback signal. The position feedback device may be a displacement sensor provided on the fast axis and the slow axis. Generally, the feedback signal of the galvanometer may also be a sinusoidal signal.

[0092] S403 , obtaining a first phase difference between the fast-axis driving signal and the fast-axis feedback signal, and obtaining a second phase difference between the laser emission period and the fast-axis driving signal.

[0093] There is a phase difference between the fast-axis feedback signal and the fast-axis driving signal.

[0094] The fast axis motion of the galvanometer generally follows the second-order resonant motion. The resonant point is the point with the best energy utilization efficiency. Generally, the motion trajectory of the ideal second-order resonant motion lags the driving signal by 90°. In other words, in an ideal situation, the phase difference between the fast axis feedback signal and the fast axis driving signal is 90°.

[0095] One of the methods of the embodiment of the present application may be to adjust the frequency of the fast-axis driving signal, and use the phase difference between the fast-axis driving signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches the maximum value as the first phase difference between the fast-axis driving signal and the fast-axis feedback signal;

[0096] The phase of the laser emission cycle is adjusted, and when the laser is aligned at a preset point, the phase difference between the laser emission cycle and the fast axis drive signal is obtained as the second phase difference. In other words, the first phase difference can be the phase difference between the fast axis drive signal and the fast axis feedback signal when the fast axis motion is at the resonant frequency. The frequency of the resonant point of the feedback signal is the resonant frequency, and the phase of the resonant point is the first phase difference between the fast axis drive signal and the fast axis feedback signal.

[0097] Considering the hardware delay, if you want to accurately know the phase of the resonance point of the fast-axis feedback signal, you generally need to calibrate it. Use a fast-axis drive signal with a fixed amplitude to drive the galvanometer and obtain the fast-axis feedback signal. When the amplitude of the fast-axis feedback signal reaches the maximum value, the corresponding frequency is the resonance point frequency. The phase of the resonance point is the first phase difference between the fast-axis drive signal and the fast-axis feedback signal.

[0098] The first phase difference between the fast-axis drive signal and the fast-axis feedback signal is locked. At this time, if the frequency of the fast-axis drive signal is adjusted, the locked first phase difference will be affected. In order to simplify the control and processing process, the phase of the laser emission cycle is adjusted, that is, the phase difference between it and the fast-axis drive signal is adjusted. When the laser is aligned at the preset point, the phase relationship between the laser emission cycle and the fast-axis drive signal at this time meets the requirements for laser synchronous control, and the laser emitted by the laser radar when it passes through the same set point back and forth in each fast-axis cycle is aligned in the vertical direction. The phase difference between the laser emission cycle and the fast-axis drive signal at this time is obtained as the second phase difference.

[0099] Another way of the embodiment of the present application may be to obtain a second phase difference between the emission period of the laser and the fast-axis drive signal, which is set to a preset value; adjust the frequency of the fast-axis drive signal, and when the laser is aligned at a preset point, obtain the phase difference between the fast-axis drive signal and the fast-axis feedback signal as the first phase difference. The present application may set the second phase difference to a preset value, and obtain the second phase difference between the emission period of the laser and the fast-axis drive signal, which is set to a preset value. In other words, the phase difference between the emission period of the laser and the fast-axis drive signal may be directly fixed to a preset value, for example, it may be 90° or other phases close to 90° (e.g., 87°, 89°, 91°, or 93°).

[0100] The second phase difference between the fast axis drive signal and the emission period of the laser is fixed. The frequency of the fast axis drive signal is adjusted, that is, the phase difference between the fast axis drive signal and the fast axis feedback signal is adjusted. As mentioned above, when the laser is aligned at the preset point, the requirements for laser synchronization control are met. The phase difference between the fast axis drive signal and the fast axis feedback signal at this time is obtained as the first phase difference. In this way, the frequency of the fast axis movement may slightly deviate from the resonant frequency of optimal efficiency. By directly setting the second phase difference to the preset value, the workload of obtaining the phase can be reduced, simplifying control and processing.

[0101] S404, phase-locking the fast-axis drive signal and the fast-axis feedback signal according to the first phase difference; and phase-fixing the laser emission period and the fast-axis drive signal according to the second phase difference, so that the laser emitted at the set point is aligned in a direction parallel to the fast axis.

[0102] Usually, when the laser radar is in operation, the fast axis motion is used for horizontal reciprocating line scanning, and the slow axis motion is used for up and down reciprocating frame scanning. After the first phase lock and the second phase lock, the laser emitted by the laser radar at the set point is aligned in the vertical direction.

[0103] The fast-axis drive signal and the fast-axis feedback signal can be phase-locked according to the first phase difference. Phase locking refers to locking the phase difference between the drive signal and the feedback signal by adjusting the frequency of the drive signal, that is, the processor adjusts the frequency of the fast-axis drive signal to stabilize the phase of the fast-axis drive signal and the fast-axis feedback signal at a set value in a closed-loop system. Phase locking can be seen in Figure 5 shown. Figure 5 In the embodiment, the first phase difference between the fast-axis drive signal and the fast-axis feedback signal is stabilized at 90°, and the set phase of the input comparator can be 90°. On the other hand, the fast-axis feedback signal of the galvanometer is obtained, and the real-time phase is obtained according to the fast-axis feedback signal, and the real-time phase is also input into the comparator. The comparator compares the set phase and the real-time phase and outputs the phase difference value to the processor. The processor adjusts the driving frequency according to the phase difference value to adjust the fast-axis drive signal, and applies the adjusted fast-axis drive signal to the galvanometer. In this way, the frequency of the fast-axis drive signal is adjusted in real time, so that the phase difference between the fast-axis drive signal and the fast-axis feedback signal is stabilized at the first phase difference, thereby achieving phase locking.

[0104] Among them, the emission period of the laser and the fast axis drive signal can be phase-fixed according to the second phase difference. The second phase difference can be a preset value, for example, it can be 90° or other phases close to 90° (for example, 87°, 89°, 91° or 93°), or it can be obtained by adjusting the phase of the emission period of the laser to meet the synchronization control requirements. The emission period of the laser is determined by the emission drive signal, and the emission drive signal and the fast axis drive signal do not affect each other and have the same period, so the time difference between the start time of the emission drive signal and the start time of the fast axis drive signal can be determined by the second phase difference. The laser radar is provided with a system clock inside, and the processor can send a clock signal to the emission drive module and the galvanometer drive module. The emission drive module and the galvanometer drive module send the fast axis drive signal and the emission drive signal respectively with a fixed time difference, the fast axis drive signal is sent to the galvanometer, and the emission drive signal is sent to the laser, so that the second phase difference between the fast axis drive signal and the emission period of the laser can be fixed to achieve phase fixing.

[0105] The so-called laser alignment operation refers to the vertical alignment of the laser emitted by the laser radar when it passes through the same set point in a fast axis cycle. For example, the vertical alignment of the laser can be determined by whether the edge of the measured object in the point cloud data is flat. In each fast axis cycle, the laser emitted when passing through the same set point is aligned in the vertical direction; in different fast axis cycles, the laser emitted when passing through the same set point is also aligned in the vertical direction.

[0106] It should be noted that when the maximum deflection angle of the galvanometer is the rated angle, the reference amplitude of the fast-axis feedback signal is obtained, and the amplitude of the fast-axis drive signal is adjusted in a closed loop so that the feedback amplitude of the fast-axis feedback signal of the galvanometer reaches the reference amplitude.

[0107] The fast axis works at a high frequency, and the main movement resistance is wind resistance. Under different air pressures, the wind resistance is different, which leads to a fixed galvanometer gain. Under different air pressures, the amplitude of the fast-axis movement is different. Because the fast-axis displacement sensor of the position feedback device is not affected by air pressure, the present application can be used. Among them, the galvanometer fast-axis displacement sensor can be used to record the deflection angle of the galvanometer. When the maximum deflection angle of the galvanometer reaches the rated angle, the amplitude of the fast-axis feedback signal of the galvanometer is obtained as the reference amplitude, and the amplitude of the fast-axis drive signal is adjusted in a closed loop so that the feedback amplitude of the fast-axis feedback signal of the galvanometer reaches the reference amplitude. Through the above processing, the fast-axis movement amplitude of the galvanometer is prevented from being affected by changes in air pressure, and real-time air pressure adaptability is achieved during the operation of the galvanometer. For the process of closed-loop adjustment of the amplitude gain of the output galvanometer, please refer to Figure 6, is a schematic diagram of the closed-loop adjustment of the amplitude of the fast-axis drive signal of the galvanometer in the galvanometer-based laser synchronization control method of the embodiment of the present application. For example, when the maximum deflection angle of the galvanometer reaches the rated angle, the amplitude of the fast-axis feedback signal of the galvanometer is 25, and 25 is used as the reference amplitude to close the loop to adjust the amplitude of the fast-axis drive signal so that the feedback amplitude of the fast-axis feedback signal of the galvanometer reaches the reference amplitude and maintains a stable relationship. According to the comparison between the reference amplitude and the real-time amplitude, the drive gain can be adjusted to adjust the drive signal, and the adjusted drive signal is applied to the galvanometer.

[0108] It should also be noted that in order to maintain a fixed scanning angle, the present application can also adopt a sealing process so that the microenvironment in which the galvanometer fast axis works is not affected by changes in external air pressure. Alternatively, a barometer can be installed on the galvanometer to sense the actual air pressure, and then the amplitude gain of the galvanometer's fast-axis drive signal to be used is calculated based on a pre-written lookup table or formula. In other words, the galvanometer's working environment can be set to a sealed environment; or, the working air pressure of the galvanometer detected by the air pressure sensor installed on the laser radar is obtained, and the preset amplitude gain of the galvanometer's fast-axis drive signal is determined based on the working air pressure for driving use.

[0109] It can be found that the scheme of the embodiment of the present application, which involves the control of the fast-axis resonant motion and the control of the laser ranging moment, can make the fast-axis motion at the optimal resonant efficiency point, while satisfying the synchronization of laser emission in different environments (temperature, air pressure). The scheme of the embodiment of the present application, on the basis of fast-axis phase locking, can realize the synchronous control of the laser emission cycle and the fast-axis motion of the galvanometer by calibrating the phase-locked phase; in addition, the fast-axis feedback sensor can be used to make an amplitude closed loop to realize air pressure adaptability without adding additional sensors or complex sealing processing.

[0110] The above introduces the method flow of the embodiment of the present application. Correspondingly, the embodiment of the present application also provides a laser synchronization control device and a laser radar based on a galvanometer.

[0111] Figure 7 It is a schematic structural diagram of a galvanometer-based laser synchronization control device according to an embodiment of the present application.

[0112] See also Figure 7 The galvanometer-based laser synchronization control device 80 provided in the present application includes: a signal acquisition module 81, a phase difference module 82, and a phase processing module 83.

[0113] The signal acquisition module 81 is used to obtain the fast-axis feedback signal when the galvanometer is scanning. When the galvanometer is scanning, the fast-axis feedback signal of the galvanometer can be obtained. Among them, the drive signal drives the galvanometer to perform fast-axis motion and slow-axis motion. The fast-axis drive signal adopts a sinusoidal drive signal to make the galvanometer in a resonant motion state in the fast-axis direction. The slow-axis drive signal adopts a sawtooth wave drive to make the galvanometer move at a uniform speed in the slow-axis direction. The fast-axis drive signal and the slow-axis drive signal are superimposed as a drive signal, and the drive signal is used to drive the galvanometer to move in two directions. A position feedback device can be provided on the galvanometer, and the position feedback device outputs a feedback signal to the outside, and the feedback signal includes a fast-axis feedback signal and a slow-axis feedback signal.

[0114] The phase difference module 82 is used to obtain a first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and to obtain a second phase difference between the laser emission period and the fast-axis drive signal. One way is to adjust the frequency of the fast-axis drive signal, and take the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches the maximum value as the first phase difference; adjust the phase of the laser emission period, and when the laser is aligned at a preset point, obtain the phase difference between the laser emission period and the fast-axis drive signal as the second phase difference. Another way is to obtain a second phase difference between the laser emission period and the fast-axis drive signal set to a preset value; adjust the frequency of the fast-axis drive signal, and when the laser is aligned at a preset point, obtain the phase difference between the fast-axis drive signal and the fast-axis feedback signal as the first phase difference.

[0115] The phase processing module 83 is used to set the phase of the fast axis drive signal according to the first phase difference and the second phase difference obtained by the phase difference module 82, so that the laser emitted at the set point is aligned in a preset direction. The phase processing module 83 can set the phase of the fast axis drive signal according to the first phase difference and the second phase difference, so that the laser emitted when passing through the same set point in the fast axis period is aligned in the vertical direction.

[0116] The laser synchronization control device based on the galvanometer provided in the present application, after obtaining the first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and obtaining the second phase difference between the laser emission cycle and the fast-axis drive signal, sets the phase of the fast-axis drive signal according to the first phase difference and the second phase difference, so that the laser emitted at the set point is aligned in a preset direction. Through the above processing, the phase difference between the fast-axis drive signal and the fast-axis feedback signal is locked, and the phase difference between the laser emission cycle and the fast-axis drive signal of the galvanometer is locked, so that the laser emitted at the set point is aligned in a preset direction, and the laser emission cycle is coordinated with the fast-axis motion, thereby better realizing the synchronous control of the laser emission cycle and the galvanometer fast-axis motion.

[0117] Figure 8It is a schematic structural diagram of a galvanometer-based laser synchronization control device according to another embodiment of the present application.

[0118] See also Figure 8 The galvanometer-based laser synchronization control device 80 provided in the present application includes: a signal acquisition module 81, a phase difference module 82, and a phase processing module 83. The phase difference module 82 includes: a first phase difference module 821 and a second phase difference module 822.

[0119] The functions of the signal acquisition module 81 and the phase processing module 83 are shown in Figure 8 Description, no further elaboration is given here.

[0120] In one embodiment:

[0121] A first phase difference module 821 is used to adjust the frequency of the fast-axis driving signal, and to use the phase difference between the fast-axis driving signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value as a first phase difference;

[0122] The second phase difference module 822 is used to adjust the phase of the laser emission period. When the laser is aligned at a preset point, the phase difference between the laser emission period and the fast axis driving signal is obtained as the second phase difference.

[0123] In one embodiment:

[0124] A second phase difference module 822, used to obtain a second phase difference between the laser emission period and the fast axis driving signal, which is set to a preset value;

[0125] The first phase difference module 821 is used to adjust the frequency of the fast-axis driving signal, and when the laser is aligned at a preset point, obtain the phase difference between the fast-axis driving signal and the fast-axis feedback signal as the first phase difference.

[0126] The galvanometer-based laser synchronization control device 80 may further include: an amplitude adjustment module (not shown in the figure).

[0127] The amplitude adjustment module is used to obtain the reference amplitude of the fast-axis feedback signal when the maximum deflection angle of the galvanometer is the rated angle, and to close-loop adjust the amplitude of the fast-axis drive signal so that the feedback amplitude of the fast-axis feedback signal of the galvanometer reaches the reference amplitude.

[0128] Fig. 9 This is a laser synchronous calibration method based on a galvanometer in another embodiment of the present application. The laser radar in the embodiment of the present application can calibrate the phase difference during operation as in the above embodiment, or the phase difference can be calibrated and written into the register of the laser radar in advance, and called during the operation of the laser radar.

[0129] See also Fig. 9 , the method comprising:

[0130] S501, place the laser radar on the calibration table, and drive the galvanometer to scan.

[0131] After the laser radar is assembled, it can be placed in a preset environment to calibrate various parameters, and the calibration results can be written into the laser radar register so that the laser radar can accurately measure and output the detection results. The preset environment usually used for calibration is equipped with a calibration platform and a target. The laser radar is placed on the calibration platform to calibrate the first phase difference and the second phase difference.

[0132] Driving the galvanometer to scan is similar to the aforementioned step S401 and will not be repeated here.

[0133] S502, obtaining a fast axis feedback signal when the galvanometer performs scanning.

[0134] When the laser radar is turned on and the galvanometer is scanning, a fast axis feedback signal of the galvanometer scanning can be obtained. Step S502 is similar to the aforementioned step S402 and will not be described in detail here.

[0135] S503 , determining a first phase difference between the fast-axis driving signal and the fast-axis feedback signal, and determining a second phase difference between the laser emission period and the fast-axis driving signal.

[0136] In this step, the frequency of the fast-axis drive signal may be adjusted, and the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value may be used as the first phase difference; the phase of the laser emission period may be adjusted, and when the laser is aligned at a preset point, the phase difference between the laser emission period and the fast-axis drive signal may be determined as the second phase difference.

[0137] In this step, the second phase difference between the laser emission period and the fast axis drive signal can also be determined as a preset value; the frequency of the fast axis drive signal is adjusted, and when the laser is aligned at the preset point, the phase difference between the fast axis drive signal and the fast axis feedback signal is determined as the first phase difference.

[0138] Among them, the laser alignment operation refers to the vertical alignment of the laser emitted when the laser radar passes through the same set point back and forth within the fast axis cycle.

[0139] For example, in order to observe the position of the laser conveniently, a receiving screen can be set in front of the laser radar. When a laser beam hits the receiving screen, a laser spot can be observed. Fig.10 shown. Fig.10 : is a comparison diagram of the embodiment of the present application in which laser alignment is achieved and laser alignment is not achieved. Figure 8 The left picture in the figure is a schematic diagram of laser alignment. Fig.10 The right picture in the figure is a schematic diagram without laser alignment. Fig.10 The right picture in the figure is the case where the adjustment is not done properly. You can see that there are 8 laser spots that are obviously offset. Fig.10 The left picture in the figure shows the adjusted situation, in which the vertical alignment of the laser is achieved, and only four laser spots are seen.

[0140] In the embodiment of the present application, in each fast axis cycle, the laser emitted when passing through the same set point back and forth is aligned in the vertical direction; in different fast axis cycles, the laser emitted when passing through the same set point back and forth is also aligned in the vertical direction.

[0141] In the case of passing the same set point back and forth, for example, multiple set points may be selected near a 90° phase delay when the laser is first required to be emitted in each fast axis cycle, such as 87°, 89°, 91° or 93°, etc., and 273°, 271°, 269°, 267°, etc. are determined as the same set point for return after a 270° phase delay, and the laser is emitted when passing the same set point back and forth. When the lasers at the two locations are aligned in the vertical direction, it indicates that the synchronous alignment is adjusted in place.

[0142] S504: Output the first phase difference and the second phase difference.

[0143] In this step, the determined first phase difference between the fast-axis driving signal and the fast-axis feedback signal, and the second phase difference between the laser emission period and the fast-axis driving signal are output.

[0144] The technical solution provided by the present application determines the first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and determines the second phase difference between the laser emission period and the fast-axis drive signal after obtaining the fast-axis feedback signal when the galvanometer is scanning; and outputs the first phase difference and the second phase difference. Through the above processing, the phase difference between the fast-axis drive signal and the fast-axis feedback signal is pre-calibrated, and the phase difference between the laser emission period and the fast-axis drive signal of the galvanometer is pre-calibrated, so that the laser radar can directly use the pre-calibrated first phase difference and second phase difference, thereby realizing the synchronous calibration of the laser emission period and the galvanometer fast-axis movement.

[0145] Fig.11 It is a schematic diagram of the structure of a galvanometer-based laser synchronous calibration device provided in an embodiment of the present application.

[0146] See also Fig.11 A laser synchronous calibration device 90 based on a galvanometer includes: an acquisition module 91, a phase difference determination module 92, and an output module 93.

[0147] The acquisition module 91 is used to acquire the fast axis feedback signal when the galvanometer performs scanning.

[0148] The phase difference determination module 92 is used to determine a first phase difference between the fast-axis driving signal and the fast-axis feedback signal, and to determine a second phase difference between the laser emission period and the fast-axis driving signal.

[0149] The output module 93 is used to output the first phase difference and the second phase difference.

[0150] The phase difference determination module 92 can adjust the frequency of the fast-axis drive signal, and use the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches the maximum value as the first phase difference; adjust the phase of the laser emission period, and when the laser is aligned at a preset point, determine the phase difference between the laser emission period and the fast-axis drive signal as the second phase difference.

[0151] The phase difference determination module 92 can also determine the second phase difference between the laser emission period and the fast axis drive signal as a preset value; adjust the frequency of the fast axis drive signal, and when the laser is aligned at the preset point, determine the phase difference between the fast axis drive signal and the fast axis feedback signal as the first phase difference.

[0152] The galvanometer-based laser synchronous calibration device provided in the present application determines the first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and determines the second phase difference between the laser emission period and the fast-axis drive signal after obtaining the fast-axis feedback signal when the galvanometer is scanning; and outputs the first phase difference and the second phase difference. Through the above processing, the phase difference between the fast-axis drive signal and the fast-axis feedback signal is pre-calibrated, and the phase difference between the laser emission period and the fast-axis drive signal of the galvanometer is pre-calibrated, so that the laser radar can directly use the pre-calibrated first phase difference and second phase difference, thereby realizing the synchronous calibration of the laser emission period and the galvanometer fast-axis movement.

[0153] Fig.12 It is a schematic diagram of the structure of the laser radar provided in an embodiment of the present application.

[0154] See also Fig.12 The laser radar 100 provided in the embodiment of the present application includes the above-mentioned galvanometer-based laser synchronization control device 80. The function and structure of the galvanometer-based laser synchronization control device 80 can be found in Figure 7 or Figure 8 The description in will not be repeated here.

[0155] Fig.13 It is a schematic diagram of the structure of a laser radar provided in another embodiment of the present application.

[0156] See also Fig.13 The laser radar 100 provided in the embodiment of the present application includes the above-mentioned galvanometer-based laser synchronous calibration device 90. The function and structure of the galvanometer-based laser synchronous control device 90 can be found in Fig.11The description in will not be repeated here.

[0157] Regarding the device in the above embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment of the method, and will not be elaborated again here.

[0158] Fig.14 It is a schematic diagram of the structure of a laser radar provided in yet another embodiment of the present application.

[0159] See also Fig.14 , the laser radar 900 includes a memory 910 and a processor 920.

[0160] The processor 920 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0161] The memory 910 may include various types of storage units, such as system memory, read-only memory (ROM), and permanent storage devices. Among them, ROM can store static data or instructions required by the processor 920 or other modules of the computer. The permanent storage device may be a readable and writable storage device. The permanent storage device may be a non-volatile storage device that does not lose the stored instructions and data even after the computer is powered off. In some embodiments, the permanent storage device uses a large-capacity storage device (such as a magnetic or optical disk, flash memory) as a permanent storage device. In some other embodiments, the permanent storage device may be a removable storage device (such as a floppy disk, optical drive). The system memory may be a readable and writable storage device or a volatile readable and writable storage device, such as a dynamic random access memory. The system memory may store some or all instructions and data required by the processor at run time. In addition, the memory 910 may include any combination of computer-readable storage media, including various types of semiconductor memory chips (such as DRAM, SRAM, SDRAM, flash memory, programmable read-only memory), and disks and / or optical disks may also be used. In some embodiments, the memory 910 may include a readable and / or writable removable storage device, such as a laser disc (CD), a read-only digital versatile disc (such as a DVD-ROM, a double-layer DVD-ROM), a read-only Blu-ray disc, an ultra-density optical disc, a flash memory card (such as an SD card, a mini SD card, a Micro-SD card, etc.), a magnetic floppy disk, etc. The computer-readable storage medium does not include carrier waves and transient electronic signals transmitted wirelessly or wired.

[0162] The memory 910 stores executable codes, and when the executable codes are processed by the processor 920 , the processor 920 can execute part or all of the methods described above.

[0163] In addition, the method according to the present application may also be implemented as a computer program or a computer program product, which includes computer program code instructions for executing some or all of the steps in the above method of the present application.

[0164] Alternatively, the present application can also be implemented as a computer-readable storage medium (or non-transitory machine-readable storage medium or machine-readable storage medium) on which executable code (or computer program or computer instruction code) is stored. When the executable code (or computer program or computer instruction code) is executed by a processor of an electronic device (or server, etc.), the processor executes part or all of the steps of the above-mentioned method according to the present application.

[0165] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A laser synchronization control method based on a galvanometer, characterized in that: include: Obtain the fast axis feedback signal when the galvanometer is scanning; Acquire a first phase difference between a fast-axis driving signal and the fast-axis feedback signal, and acquire a second phase difference between an emission period of a laser and the fast-axis driving signal; Setting the phase of the fast axis drive signal according to the first phase difference and the second phase difference so that the laser emitted at a set point is aligned in a preset direction; The method includes: phase-locking the fast-axis drive signal and the fast-axis feedback signal according to the first phase difference; The phase of the laser emission period and the fast axis driving signal is fixed according to the second phase difference, so that the emitted laser light is aligned in the vertical direction when passing through the same set point in the fast axis period.

2. The method according to claim 1, characterized in that The obtaining of a first phase difference between the fast axis drive signal and the fast axis feedback signal, and the obtaining of a second phase difference between the emission period of the laser and the fast axis drive signal, include: adjusting the frequency of the fast-axis drive signal, and taking the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value as a first phase difference; The phase of the emission period of the laser is adjusted, and when the laser is aligned at a preset point, the phase difference between the emission period of the laser and the fast axis driving signal is obtained as a second phase difference.

3. The method according to claim 1, characterized in that The obtaining of a first phase difference between the fast axis drive signal and the fast axis feedback signal, and the obtaining of a second phase difference between the emission period of the laser and the fast axis drive signal, include: Acquiring a second phase difference between an emission period of the laser and the fast axis driving signal, which is set to a preset value; The frequency of the fast-axis driving signal is adjusted, and when the laser is aligned at a preset point, a phase difference between the fast-axis driving signal and the fast-axis feedback signal is obtained as a first phase difference.

4. The method according to any one of claims 1 to 3, characterized in that: The method further comprises: When the maximum deflection angle of the galvanometer is the rated angle, the reference amplitude of the fast-axis feedback signal is obtained, and the amplitude of the fast-axis drive signal is adjusted in a closed loop so that the feedback amplitude of the fast-axis feedback signal of the galvanometer reaches the reference amplitude.

5. A laser synchronization control device based on a galvanometer, characterized in that: include: A signal acquisition module is used to obtain a fast axis feedback signal when the galvanometer is scanning; A phase difference module, used to obtain a first phase difference between a fast-axis driving signal and the fast-axis feedback signal, and to obtain a second phase difference between an emission period of a laser and the fast-axis driving signal; a phase processing module, configured to perform phase setting on the fast axis drive signal according to the first phase difference and the second phase difference acquired by the phase difference module, so that the laser emitted at a set point is aligned in a preset direction; The method includes: phase-locking the fast-axis drive signal and the fast-axis feedback signal according to the first phase difference; The phase of the laser emission period and the fast axis driving signal is fixed according to the second phase difference, so that the emitted laser light is aligned in the vertical direction when passing through the same set point in the fast axis period.

6. The device according to claim 5, characterized in that The phase difference module comprises: A first phase difference module, used for adjusting the frequency of the fast-axis drive signal, and taking the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value as a first phase difference; The second phase difference module is used to adjust the phase of the laser emission period, and when the laser is aligned at a preset point, obtain the phase difference between the laser emission period and the fast axis drive signal as the second phase difference.

7. The device according to claim 5, characterized in that The phase difference module comprises: A second phase difference module, used to obtain a second phase difference between the emission period of the laser and the fast axis drive signal, which is set to a preset value; The first phase difference module is used to adjust the frequency of the fast-axis drive signal, and when the laser is aligned at a preset point, obtain the phase difference between the fast-axis drive signal and the fast-axis feedback signal as the first phase difference.

8. A laser synchronous calibration method based on a galvanometer, characterized in that: include: Obtain the fast axis feedback signal when the galvanometer is scanning; Determine a first phase difference between a fast-axis drive signal and the fast-axis feedback signal, and determine a second phase difference between an emission period of the laser and the fast-axis drive signal; outputting the first phase difference and the second phase difference; Wherein, the determining of a first phase difference between the fast-axis drive signal and the fast-axis feedback signal, and the determining of a second phase difference between the emission period of the laser and the fast-axis drive signal, include: adjusting the frequency of the fast-axis drive signal, and taking the phase difference between the fast-axis drive signal and the fast-axis feedback signal when the amplitude of the fast-axis feedback signal reaches a maximum value as a first phase difference; adjusting the phase of the laser emission cycle, and when the laser is aligned at a preset point, determining the phase difference between the laser emission cycle and the fast axis drive signal as a second phase difference; or, Determine that a second phase difference between an emission period of the laser and the fast axis drive signal is a preset value; adjusting the frequency of the fast-axis drive signal, and when the laser is aligned at a preset point, determining a phase difference between the fast-axis drive signal and the fast-axis feedback signal as a first phase difference; The alignment includes aligning the emitted laser light in a vertical direction when the laser light passes through the same set point in a fast axis cycle.

9. A laser radar, characterized in that: It comprises a galvanometer-based laser synchronization control device as described in any one of claims 5 to 7.

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