Laser optical system with optical anti-vibration function and control method

Abstract

The invention discloses a laser optical system with an optical anti-vibration function and a control method. The system comprises a laser emitting module, a light beam transmitting and focusing module and an optical anti-vibration module. The laser emission module is used for generating and outputting a laser beam; the light beam transmission and focusing module comprises a focusing lens and a reflecting mirror and is used for transmitting a laser beam and forming a focusing light spot on a target surface; the optical anti-shake module comprises a shake detection unit, a control unit and a compensation adjustment unit; the jitter detection unit is located on the laser emission module and used for detecting the position variation of the laser emission module and sending the position variation to the control unit. The control unit calculates the offset of the laser beam according to the position variation and generates a control instruction; and the compensation adjustment unit drives the light beam transmission and focusing module to perform compensation action according to the control instruction. According to the invention, the laser beam is ensured to be stably focused on the target, and the handheld laser operation effect is obviously improved.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of laser optical equipment, and in particular to a laser optical system with optical anti-shake function and a control method thereof. Background Art

[0002] With the widespread application of laser technology in various fields, handheld laser devices have gained widespread use due to their convenience and flexibility. However, during handheld operation, the inevitable vibrations of the human body can easily cause the laser beam's focal point to shift when it impacts the target surface. This shift can lead to uneven energy distribution, which in turn affects processing results. For example, during laser cleaning, incomplete cleaning can leave streaks, resulting in reduced cutting accuracy and poor weld quality in laser processing. In the field of laser medical treatment, it can also affect the accuracy and safety of treatments.

[0003] Traditional solutions often focus on optimizing the mechanical structure of the handheld device to reduce vibration transmission, but this has limited effectiveness and cannot fundamentally overcome the optical focus instability caused by hand tremors. Therefore, a technical solution that can effectively offset the effects of vibration at the optical level is urgently needed to ensure the accuracy and quality of handheld laser operations. Summary of the Invention

[0004] In response to the technical problems existing in the prior art, the present invention provides a laser optical system and a control method with optical image stabilization function, which ensure that the laser beam is always stably focused on the target during handheld operation.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: A laser optical system with optical image stabilization function, comprising a laser emission module, a beam transmission and focusing module, and an optical image stabilization module; The laser emission module is used to generate and output a laser beam; The beam transmission and focusing module includes a focusing lens and a reflector for transmitting the laser beam and forming a focused light spot on the target surface; The optical image stabilization module includes a vibration detection unit, a control unit and a compensation adjustment unit; The jitter detection unit is located on the laser emitting module and is used to detect the position change of the laser emitting module and send it to the control unit; The control unit calculates the offset of the laser beam according to the position change and generates a control instruction; The compensation adjustment unit drives the light beam transmission and focusing module to perform compensation actions according to the control instruction.

[0006] Preferably, the vibration detection unit includes a gyroscope and an acceleration sensor; The gyroscope is used to detect the angular velocity change of the laser emission module; The acceleration sensor is used to detect the linear acceleration changes of the laser emission module in the X-axis, Y-axis and Z-axis directions; The jitter detection unit performs data processing in combination with a Kalman filter algorithm to eliminate noise interference.

[0007] Preferably, the compensation adjustment unit is configured to drive the focusing lens for adjustment; wherein the compensation action includes realizing the displacement adjustment of the focusing lens in the X-axis and Y-axis planes through a micro motor; wherein the displacement adjustment is used to correct the laser beam focus point position offset caused by jitter.

[0008] Preferably, the compensation adjustment unit is configured to drive the reflector for adjustment; wherein the compensation action includes fine-tuning the angle of the reflector through a precision electric rotation mechanism; wherein the angle fine-tuning is used to correct the deviation in the propagation direction of the laser beam caused by jitter.

[0009] Preferably, the compensation adjustment unit also includes a position detection sensor for detecting the position of the focusing lens and / or the position of the reflector to form a closed-loop control; wherein the position detection of the focusing lens adopts a laser displacement sensor, which calculates the displacement by measuring the time delay of the reflected light; the position detection of the reflector adopts a magnetoresistive angle sensor, which measures the angle by detecting the change of the magnetic field.

[0010] The present invention also discloses a control method for the laser optical system with optical image stabilization function as described above, comprising the steps of: The laser emission module generates and outputs a laser beam; The beam transmission and focusing module transmits the laser beam and forms a focused light spot on the target surface; The jitter detection unit detects the position change of the laser emitting module and sends it to the control unit; The control unit calculates the offset of the laser beam according to the position change and generates a control instruction; The compensation adjustment unit drives the light beam transmission and focusing module to perform compensation actions according to the control instruction.

[0011] Preferably, the control unit calculates the offset of the laser beam based on the position change and generates a control instruction, using an optimization algorithm based on a combination of fuzzy control and PID control; the fuzzy control is used to quickly determine the initial control parameters of the focusing lens and the reflector according to the type and amplitude of the jitter; the PID control is used to fine-tune the control parameters to ensure the stability and accuracy of the system.

[0012] Preferably, the specific process of fuzzy control is: In fuzzy control, the input variables include the type of jitter and the amplitude of jitter. The jitter type includes translation or rotation. The amplitude of jitter is classified as small, medium, or large. The output variables include the control weights of the focusing lens and the reflector. Fuzzy rules: According to different jitter types and amplitudes, corresponding fuzzy rules are formulated: when translation jitter is detected and the amplitude is large, the control weight of the focus lens is increased; when rotation jitter is detected and the amplitude is large, the control weight of the reflector is increased.

[0013] Preferably, the specific process of the compensation adjustment unit driving the beam transmission and focusing module to perform the compensation action according to the control instruction is: The control unit sends control signals to the micro motor of the focusing lens and the precision electric rotation mechanism of the reflector at the same time based on the control parameters calculated by the optimization control algorithm, thus achieving synchronous and coordinated adjustment of the two lenses; The focusing lens position is detected by a laser displacement sensor, which emits a laser beam to the reflective coating on the back of the focusing lens and accurately calculates the displacement of the focusing lens by measuring the time delay of the reflected light. The reflector position is detected by a high-precision angle sensor, which uses the magnetoresistance effect to accurately measure the angle of the reflector by detecting changes in the magnetic field at the reflector shaft. The displacement of the focusing lens and the angle of the reflector are transmitted to the control unit to achieve closed-loop control.

[0014] Preferably, the position change is filtered using a Kalman filter algorithm.

[0015] Compared with the prior art, the advantages of the present invention are: The present invention uses precise optical image stabilization technology to ensure that the laser beam is always stably focused on the target during handheld operation, avoiding energy dispersion and deviation caused by jitter, effectively solving the problem of zebra patterns appearing during processing due to unstable handholding of the handheld cleaning machine, improving the cleaning effect and quality, and significantly improving the operation accuracy; the operator does not need to deliberately maintain an extremely stable handheld state, which reduces the operation difficulty and labor intensity, allowing the handheld laser equipment to be more flexibly applied to various complex working environments, expanding the application scenarios and scope, such as laser cleaning, laser processing, laser medical treatment and other handheld operation scenarios with high requirements for laser beam stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the overall structure of the laser optical system of the present invention.

[0017] Figure 2 Schematic diagram of the optical image stabilization principle in the present invention.

[0018] Figure 3 This is a schematic diagram of the principle of the compensation adjustment unit driving the focus lens to adjust the focus lens in the present invention.

[0019] Figure 4 This is a schematic diagram of the principle of the compensation adjustment unit driving the reflector to adjust the reflector.

[0020] Figure 5 This is a flow chart of the deep learning-based predictive jitter compensation algorithm in the present invention.

[0021] Legend: 1. Laser; 2. Collimating mirror; 3. Reflector; 4. Digital signal processor; 5. Accelerometer; 6. Rotating motor; 7. Gyroscope; 8. Micro motor; 9. Focusing lens; 10. Workpiece; 11. Stage; 12. Computer. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1-Figure 2 As shown, the laser optical system with optical image stabilization function provided by an embodiment of the present invention includes a laser emitting module, a beam transmission and focusing module, and an optical image stabilization module; wherein the laser emitting module is used to generate and output a laser beam; the beam transmission and focusing module includes a focusing lens and a reflector, which is used to transmit the laser beam and form a focused light spot on the target surface; the optical image stabilization module includes a jitter detection unit, a control unit and a compensation adjustment unit; the jitter detection unit is located on the laser emitting module, and is used to detect the position change of the laser emitting module and send it to the control unit; the control unit calculates the offset of the laser beam according to the position change and generates a control instruction; the compensation adjustment unit drives the beam transmission and focusing module to perform compensation action according to the control instruction.

[0024] Specifically, the laser transmitter module utilizes a high-performance, miniaturized laser capable of generating laser beams with specific wavelengths, powers, and pulse characteristics tailored to the specific application requirements. For example, in laser cleaning applications, a pulsed laser with a wavelength tailored to the contaminant's absorption characteristics can be selected for efficient decontamination. The module is also equipped with a comprehensive heat dissipation device (water cooling) to ensure stable operation of the laser source over extended periods, preventing power fluctuations or malfunctions caused by overheating.

[0025] Specifically, the beam transmission and focusing module includes a collimator, a high-precision focusing lens and a reflector, which is responsible for transmitting the laser beam generated by the laser emission module according to a predetermined optical path, and through precise focusing, forming an ideal light spot on the target surface.

[0026] Specifically, the vibration detection unit includes a high-precision gyroscope and an accelerometer. The accelerometer accurately senses the linear acceleration changes of the handheld device in the three axes (X, Y, and Z), while the gyroscope sensitively captures the angular velocity changes of the device. The two work together to monitor the vibration during the hand-held process in real time and in all directions, and convert the detected physical quantities into electrical signals, which are quickly transmitted to the control unit.

[0027] Since the jitter data obtained by the laser optical system in actual applications may contain various noises and interferences, it is necessary to design a special data preprocessing process based on the characteristics of the laser optical system. In terms of detection methods, the Kalman filter algorithm is combined to process the sensor output signal. This algorithm can effectively fuse multiple sets of sensor data and eliminate noise interference. The Kalman filter algorithm is based on the system state space model. Through the two steps of prediction and update, it can estimate the optimal value of the signal in real time, effectively remove noise interference, and more accurately track signal changes even in strong noise environments. It can also fuse the data of the gyroscope and the acceleration sensor. By establishing the system's state equation and observation equation, it can accurately estimate the state of the system and improve measurement accuracy and stability. Traditional methods usually use simple methods such as mean filtering and median filtering, which have limited effects on suppressing random noise and are difficult to accurately extract real signals in complex environments.

[0028] Combined with algorithms such as Kalman filtering, data obtained from sensors such as gyroscopes is denoised and features extracted to improve the quality of data input into deep learning models, enabling the models to better learn the true characteristics of jitter.

[0029] Specifically, if Figure 5 As shown, the control unit utilizes a digital signal processor (DSP) with advanced built-in algorithms. After receiving the electrical signal from the jitter detection unit, this unit, based on a preset mathematical model and algorithm, quickly calculates the laser beam offset caused by jitter, including positional and angular deviations. It then generates corresponding control instructions and transmits them to the compensation adjustment unit. This calculation utilizes a predictive jitter compensation algorithm based on deep learning. By learning from a large amount of historical jitter data, this algorithm can predict jitter trends up to 0.05 seconds in advance, enabling more accurate calculation of the laser beam offset. Compared to traditional algorithms based on physical models, this algorithm can adapt to more complex and variable jitter conditions.

[0030] The existing deep learning model architecture is adjusted and optimized based on the specific performance requirements and jitter characteristics of handheld laser optical systems. For example, given the high-precision and real-time requirements for calculating laser beam offset, the model's layers can be reduced to reduce computational complexity. Meanwhile, specialized convolutional or recurrent layers tailored to laser optical system jitter patterns are added to better capture the dynamic characteristics of jitter. For example, the convolutional layer employs a depthwise separable convolutional structure of "3×3 depthwise convolution + 1×1 pointwise convolution" to efficiently exploit the spatial coupling characteristics of the gyroscope (angular velocity) and accelerometer (linear acceleration) at the same moment (e.g., the correlation between abnormal X-axis acceleration and increased Z-axis angular velocity during tilt). The recurrent layer employs a bidirectional LSTM coupled with an attention mechanism to simultaneously learn jitter trends over both the past and present, and the present and future. By leveraging bidirectional temporal learning and the attention mechanism to prioritize the most recent three time steps (60ms window), the model accurately models the dynamic relationship between historical jitter and future offset, specifically tracking high-frequency micro-tremors and sudden jitter of 5-10Hz.

[0031] Specifically, if Figure 3-Figure 4 As shown in the figure, the compensation adjustment unit precisely drives the optical elements to perform compensation actions according to the instructions of the control unit. For the focusing lens, a micro-motor is used to achieve rapid and micro-displacement adjustment in the X and Y planes to ensure the stability of the focus point of the laser beam in the horizontal and vertical directions; for the reflector, a precision electric rotation mechanism is used to correct the deviation of the beam propagation direction caused by jitter. The focusing lens and the reflector adopt a synchronous and coordinated adjustment mechanism. When jitter is detected, the control unit sends control signals to the micro-motor of the focusing lens and the precision electric rotation mechanism of the reflector at the same time through an optimized control algorithm based on the type and amplitude of the jitter. The specific process is as follows: Jitter type and amplitude: a. Translational jitter: Linear displacement of the handheld device in the horizontal (X-axis) and vertical (Y-axis) directions, such as shaking the hand back and forth or left and right. Typical amplitude range: ±0.5mm to ±5mm (effective adjustment range of the focusing lens). b. Rotational jitter: Angular deviation of the device around the optical axis (Z-axis), such as laser beam deviation caused by wrist rotation. Typical amplitude range: ±0.01° to ±0.5° (effective adjustment range of the reflector).

[0032] Jitter detection uses a gyroscope and accelerometer. The gyroscope measures the device's angular velocity, while the accelerometer measures its acceleration. By analyzing this data, the type and magnitude of jitter can be determined. For example, if the accelerometer detects a continuous change in the device's acceleration along the X-axis, it can be determined to be translational jitter along the X-axis. If the gyroscope detects a change in the device's angular velocity about the Z-axis, it can be determined to be rotational jitter about the Z-axis.

[0033] Of course, in addition to the jitter data directly measured by the sensor, it is possible to consider incorporating information such as the laser beam's reflection angle on the lens and the current position of the focusing lens into the deep learning model. This additional information can help the model more comprehensively understand the system state and thus more accurately predict the laser beam offset.

[0034] Signal processing: Filtering: The original detection signal may contain noise. Kalman filtering is used to remove noise and improve signal accuracy. Kalman filtering uses two steps: prediction and update to optimally estimate the signal.

[0035] Feature extraction: Extract jitter features, such as frequency and amplitude, from the filtered signal. For example, the time domain signal is converted to the frequency domain using a fast Fourier transform (FFT) to analyze the main frequency components of the jitter.

[0036] Optimization Control Algorithm: Utilizes an optimization algorithm based on a combination of fuzzy control and PID control. Fuzzy control is used to quickly determine the initial control parameters for the focusing lens and reflector based on the type and amplitude of the jitter; PID control is used to fine-tune the control parameters to ensure system stability and accuracy.

[0037] Among them, fuzzy control: Input variables: type of jitter (translation or rotation), amplitude of jitter (small, medium, large).

[0038] Output variables: Control weights of the focusing lens and mirror (range 0 - 1).

[0039] Fuzzy rules: Develop corresponding fuzzy rules based on different jitter types and amplitudes. For example, when a large translational jitter is detected, the focus lens's control weight is increased; when a large rotational jitter is detected, the reflector's control weight is increased.

[0040] Among them, PID control: Proportional (P) control: Adjusts the control amount proportionally based on the current error (the difference between the actual position and the desired position). A larger proportional coefficient results in a faster system response, but may also lead to system instability.

[0041] Integral (I) control: Integrates the error to eliminate the system's steady-state error. A larger integral coefficient eliminates the steady-state error faster, but may cause the system to overshoot.

[0042] Derivative (D) control: Based on the rate of change of the error, the future trend of the error is predicted, and the control variable is adjusted in advance to reduce system oscillation. A larger differential coefficient increases the system's anti-interference ability, but may also amplify noise.

[0043] Based on the control parameters calculated by the optimized control algorithm, the control unit simultaneously sends control signals to the micro-motor of the focusing lens and the precision electric rotation mechanism of the reflector, achieving synchronous and coordinated adjustment of the two lenses. The sensor transmits the adjusted position information to the digital signal processor, thereby realizing a closed-loop control. The focusing lens position is detected by a laser displacement sensor, which transmits a laser beam to the reflective coating on the back of the focusing lens and accurately calculates the displacement of the focusing lens by measuring the time delay of the reflected light. The reflector position is detected by a high-precision angle sensor. By using the magnetoresistive effect, it detects the changes in the magnetic field at the reflector shaft and accurately measures the angle of the reflector. Throughout the entire process, the compensation adjustment unit can dynamically and continuously adjust the optical components according to the real-time instructions of the control unit to ensure the timeliness and accuracy of optical image stabilization.

[0044] The present invention uses precise optical image stabilization technology to ensure that the laser beam is always stably focused on the target during handheld operation, avoiding energy dispersion and deviation caused by jitter, effectively solving the problem of zebra patterns appearing during processing due to unstable handholding of the handheld cleaning machine, improving the cleaning effect and quality, and significantly improving the operation accuracy; the operator does not need to deliberately maintain an extremely stable handheld state, which reduces the operation difficulty and labor intensity, allowing the handheld laser equipment to be more flexibly applied to various complex working environments, expanding the application scenarios and scope, such as laser cleaning, laser processing, laser medical treatment and other handheld operation scenarios with high requirements for laser beam stability.

[0045] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0046] The laser 1 emits light through the processing software built into the computer 12. The X and Y axis scanning galvanometers can drive the laser motion processing. The laser is focused on the surface of the workpiece 10 through the collimator 2, the reflector 3, and the focusing lens 9. The workpiece 10 is placed on the stage 11. The optical image stabilization module includes a digital signal processor 4, an acceleration sensor 5, a rotary motor 6, a gyroscope 7, and a micro motor 8. When an operator holds the laser head of the optical system of the present invention and their hand shakes, the vibration detection unit (gyroscope 7 and accelerometer 5) installed inside the laser head system immediately captures the vibration information, converts it into an electrical signal, and transmits it to the digital signal processor 4. The digital signal processor 4 quickly processes and analyzes the received signal, using a built-in algorithm to calculate the offset and angular change of the laser beam in the X, Y, and Z directions.

[0047] Based on the calculation results, the digital signal processor 4 generates precise control instructions and sends them to the compensation adjustment unit. If the laser beam deviates in the X-axis direction, the compensation adjustment unit drives the focusing lens 9 to make corresponding displacement adjustments in the X-axis via a micromotor, refocusing the laser beam to the predetermined target position. If there is angular deviation, such as due to rotational jitter around the Y-axis, the compensation adjustment unit controls the reflector to fine-tune the angle via a precision electric rotation mechanism to correct the deviation in the beam propagation direction caused by this jitter. The compensation unit has a built-in sensor, which transmits the adjusted position information to the digital signal processor 4, thus achieving closed-loop control.

[0048] Throughout the entire operation, the jitter detection unit continuously monitors jitter and feeds real-time signals back to the digital signal processor 4. The digital signal processor 4 continuously updates control instructions based on the new jitter information. The compensation adjustment unit dynamically adjusts the optical elements accordingly, and the sensor then transmits the adjusted position information to the digital signal processor 4. This repetitive cycle achieves real-time, precise and stable control of the laser beam focus, effectively offsetting the adverse effects of hand-held jitter on laser operations and ensuring efficient and accurate operation.

[0049] The present invention introduces an advanced optical image stabilization mechanism to monitor and compensate for beam deviation caused by hand-held shaking in real time, ensuring that the laser beam is stably focused on the target and significantly improving the effect of handheld laser operations.

[0050] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A laser optical system with optical image stabilization function, characterized in that: Including laser emission module, beam transmission and focusing module, optical image stabilization module; The laser emission module is used to generate and output a laser beam; The beam transmission and focusing module includes a focusing lens and a reflector for transmitting the laser beam and forming a focused light spot on the target surface; The optical image stabilization module includes a vibration detection unit, a control unit and a compensation adjustment unit; The jitter detection unit is located on the laser emitting module and is used to detect the position change of the laser emitting module and send it to the control unit; The control unit calculates the offset of the laser beam according to the position change and generates a control instruction; The compensation adjustment unit drives the light beam transmission and focusing module to perform compensation actions according to the control instruction.

2. The laser optical system with optical image stabilization function according to claim 1, characterized in that: The vibration detection unit includes a gyroscope and an acceleration sensor; The gyroscope is used to detect the angular velocity change of the laser emission module; The acceleration sensor is used to detect the linear acceleration changes of the laser emission module in the X-axis, Y-axis and Z-axis directions; The jitter detection unit performs data processing in combination with a Kalman filter algorithm to eliminate noise interference.

3. The laser optical system with optical image stabilization function according to claim 2, characterized in that: The compensation adjustment unit is configured to drive the focusing lens for adjustment; the compensation action includes achieving displacement adjustment of the focusing lens in the X-axis and Y-axis planes through a micro motor; the displacement adjustment is used to correct the position offset of the laser beam focus point caused by jitter.

4. The laser optical system with optical image stabilization function according to claim 2 or 3, characterized in that: The compensation adjustment unit is configured to drive the reflector for adjustment; wherein the compensation action includes fine-tuning the angle of the reflector through a precision electric rotation mechanism; wherein the angle fine-tuning is used to correct the deviation in the propagation direction of the laser beam caused by jitter.

5. The laser optical system with optical image stabilization function according to claim 2 or 3, characterized in that: The compensation adjustment unit also includes a position detection sensor for detecting the position of the focusing lens and / or the position of the reflector to form a closed-loop control; the position detection of the focusing lens adopts a laser displacement sensor, which calculates the displacement by measuring the time delay of the reflected light; the position detection of the reflector adopts a magnetoresistive angle sensor, which measures the angle by detecting the change of the magnetic field.

6. A control method for a laser optical system with optical image stabilization function according to any one of claims 1 to 5, characterized in that: Including steps: The laser emission module generates and outputs a laser beam; The beam transmission and focusing module transmits the laser beam and forms a focused light spot on the target surface; The jitter detection unit detects the position change of the laser emitting module and sends it to the control unit; The control unit calculates the offset of the laser beam according to the position change and generates a control instruction; The compensation adjustment unit drives the light beam transmission and focusing module to perform compensation actions according to the control instruction.

7. The control method according to claim 6, wherein: The control unit calculates the offset of the laser beam based on the position change and generates control instructions, using an optimization algorithm based on the combination of fuzzy control and PID control; Fuzzy control is used to quickly determine the initial control parameters of the focusing lens and reflector according to the type and amplitude of the jitter; PID control is used to fine-tune the control parameters to ensure the stability and accuracy of the system.

8. The control method according to claim 7, characterized in that: The specific process of fuzzy control is as follows: In fuzzy control, the input variables include the type of jitter and the amplitude of jitter. The jitter type includes translation or rotation. The amplitude of jitter is classified as small, medium, or large. The output variables include the control weights of the focusing lens and the reflector. Fuzzy rules: According to different jitter types and amplitudes, corresponding fuzzy rules are formulated: when translation jitter is detected and the amplitude is large, the control weight of the focus lens is increased; when rotation jitter is detected and the amplitude is large, the control weight of the reflector is increased.

9. The control method according to claim 8, characterized in that: The specific process of the compensation adjustment unit driving the beam transmission and focusing module to perform compensation action according to the control instruction is as follows: The control unit sends control signals to the micro motor of the focusing lens and the precision electric rotation mechanism of the reflector at the same time based on the control parameters calculated by the optimization control algorithm, thus achieving synchronous and coordinated adjustment of the two lenses; The focusing lens position is detected by a laser displacement sensor, which emits a laser beam to the reflective coating on the back of the focusing lens and accurately calculates the displacement of the focusing lens by measuring the time delay of the reflected light. The reflector position is detected by a high-precision angle sensor, which uses the magnetoresistance effect to accurately measure the angle of the reflector by detecting changes in the magnetic field at the reflector shaft. The displacement of the focusing lens and the angle of the reflector are transmitted to the control unit to achieve closed-loop control.

10. The control method according to any one of claims 6 to 9, characterized in that: The position change is filtered using the Kalman filter algorithm.

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