A dual-angle reflector automatic tracking system based on incident light angle detection and a control method thereof

Abstract

The application discloses a kind of double-face angle reflector automatic tracking system and control method based on incident light angle detection, belong to optical beam control technical field, it includes to incident light beam spectrometer, separate out detection beam and reflected working light beam, collect the optical distribution information of detection beam and generate spot position coordinate data, solve the incident light direction angle data, again according to its and the space geometric mapping relationship of double-face angle reflector solving target attitude angle data, compare actual attitude feedback data and generate servo drive instruction to obtain attitude deviation data, drive double-face angle reflector space rotation, make symmetric plane normal and incident light beam propagation direction coincide, guide reflected working light beam along original light path reverse output.The application can be under the condition that incident light direction dynamically changes, automatically make the symmetric plane normal of double-face angle reflector and incident light beam propagation direction coincide, guide reflected working light beam along original light path reverse output.

Description

Technical Field

[0001] This invention relates to the field of optical beam control technology, and in particular to an automatic tracking system and control method for a two-sided corner reflector based on incident light angle detection. Background Technology

[0002] Corner reflectors are optical devices that can reverse the direction of incident light beams. Common forms include corner prisms consisting of three mutually perpendicular reflecting surfaces and bifacial corner reflectors consisting of two mutually perpendicular plane mirrors. Due to this optical characteristic of returning light along its original path, these devices are widely used in free-space optical communication, laser ranging, and optical aiming. Bifacial corner reflectors are simple in structure, have a large reflecting area, and are low in manufacturing cost, making them a commonly used device for long-distance beam reversal.

[0003] In the prior art, corner reflectors are mostly fixedly installed at the end of the optical path, relying on the three perpendicular geometric structures of the corner prism itself to achieve passive reverse output of the incident beam within a certain angle range; for double-sided corner reflectors, a one-time manual pre-alignment is usually completed during the assembly stage according to the predetermined incident light direction, so that the symmetrical surface of the double-sided corner reflector is in a fixed posture that matches the predetermined incident direction, and this posture remains unchanged throughout the entire working process.

[0004] When the incident beam is obliquely incident, the effective reflection aperture of a fixedly installed corner prism decreases as the incident angle increases. To obtain a larger reflection aperture, large-sized devices need to be manufactured, which increases the weight and cost. A bifacial corner reflector that has been manually pre-aligned once can only return along the original path near the predetermined incident angle. When the incident light direction deviates from the predetermined direction, it cannot maintain the coincidence of the normal of the symmetry plane and the propagation direction of the incident beam, and the reverse output beam deviates from the original optical path. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an automatic tracking system and control method for a bifacial corner reflector based on incident light angle detection. The system employs a closed-loop tracking method that samples the incident beam, calculates the incident light direction angle, and drives a dual-axis servo turntable to adjust the bifacial corner reflector's pose in real time. This method automatically aligns the normal of the bifacial corner reflector's symmetry plane with the direction of the incident beam under dynamically changing incident light direction conditions, guiding the reflected working beam to reverse along the original optical path for output.

[0006] The above objectives can be achieved through the following approach: An automatic tracking control method for a bifacial corner reflector based on incident light angle detection includes: receiving an externally input incident light beam; performing beam splitting on the incident light beam to separate a probe beam and a reflective working beam; acquiring optical distribution information of the probe beam, extracting the position offset from the optical distribution information, and generating spot position coordinate data; converting the spot position coordinate data and calculating the incident light direction angle data of the incident light beam relative to the system reference frame; performing attitude calculation based on the spatial geometric mapping relationship between the incident light direction angle data and the bifacial corner reflector to generate target attitude angle data for adjusting the bifacial corner reflector; comparing the target attitude angle data with the currently acquired actual attitude feedback data to calculate attitude deviation data, and generating servo drive commands based on the attitude deviation data; executing the servo drive commands to drive the bifacial corner reflector to rotate spatially, so that the normal of the symmetry plane of the bifacial corner reflector coincides with the propagation direction of the incident light beam, and guiding the reflective working beam to output in the reverse direction along the original optical path.

[0007] Optionally, receiving the externally input incident beam and performing beam splitting processing on the incident beam to separate the probe beam and the reflective working beam includes: receiving the externally input incident beam, extracting the ambient stray light frequency band, and transmitting the target working wavelength beam; guiding the target working wavelength beam into the beam splitting medium, dividing the target working wavelength beam into a first energy beam and a second energy beam according to the beam splitting energy ratio; converging the first energy beam to form a probe beam, and guiding the second energy beam to be projected onto a bifacial reflector to form a reflective working beam.

[0008] Optionally, the step of acquiring the optical distribution information of the probe beam, extracting the position offset in the optical distribution information, and generating spot position coordinate data includes: receiving the probe beam and projecting it onto different quadrant regions of the photoelectric sensing plane, generating weak photoelectric signals corresponding to each quadrant region; amplifying and filtering the high-frequency noise components in the weak photoelectric signals, and outputting a simulated spot intensity signal; converting the simulated spot intensity signal into a digital quantity, and performing coordinate mapping based on the ratio of the digital quantity differences between each quadrant region to generate spot position coordinate data.

[0009] Optionally, the step of acquiring the optical distribution information of the probe beam, extracting the position offset from the optical distribution information, and generating spot position coordinate data further includes: receiving the probe beam and performing spatial discretization sampling using an area array photoelectric sensor array to output a digital image matrix containing grayscale distribution information; setting a background noise threshold to perform binarization denoising processing on the digital image matrix to extract the effective spot connected region; and performing grayscale weighted centroid calculation on the pixels within the effective spot connected region to calculate the spot position coordinate data.

[0010] Optionally, the step of converting the spot position coordinate data and calculating the incident beam direction angle data relative to the system reference frame includes: extracting the horizontal and vertical axial offsets from the spot position coordinate data; performing inverse trigonometric function operations on the horizontal axial offset using the focal length parameters of the front optical converging component to calculate the horizontal azimuth angle data; performing the same inverse trigonometric function operations on the vertical axial offset to calculate the vertical pitch angle data; and fusing the horizontal azimuth angle data and the vertical pitch angle data to construct the incident beam direction angle data.

[0011] Optionally, the step of calculating the attitude based on the incident light direction angle data and the spatial geometric mapping relationship between the bifacial reflector to generate target attitude angle data for adjusting the bifacial reflector includes: parsing the incident light direction angle data to separate the horizontal azimuth angle data and the vertical pitch angle data that characterize the incident direction; mapping the horizontal azimuth angle data to a first axial target angle for the bifacial reflector to rotate around the corresponding common edge; extracting the vertical pitch angle data and performing a 1 / 2 dimensionality reduction scaling to generate a second axial target angle for the bifacial reflector to rotate around the plane perpendicular to the common edge; and combining the first axial target angle and the second axial target angle to generate target attitude angle data.

[0012] Optionally, the step of comparing the target attitude angle data with the currently acquired actual attitude feedback data, calculating the attitude deviation data, and generating servo drive commands based on the attitude deviation data includes: reading the real-time phase pulse of the position encoding device installed on the rotary actuator and parsing the actual attitude feedback data; comparing the target attitude angle data with the actual attitude feedback data, calculating the dynamic difference of each motion axis, and generating attitude deviation data; inputting the attitude deviation data into a preset proportional-integral-derivative control model for control law calculation, and outputting servo drive commands.

[0013] Optionally, the step of inputting the attitude deviation data into a preset proportional-integral-derivative (PID) control model for control law calculation and outputting servo drive commands includes: monitoring the rate of change of the attitude deviation data and extracting dynamic feature variables characterizing the degree of change in beam movement; dynamically adjusting the proportional coefficient and integral coefficient in the PID model based on the dynamic feature variables to generate an updated PID model; and recalculating the control law for the current attitude deviation data using the updated PID model to generate servo drive commands.

[0014] Optionally, executing the servo drive command to drive the bifacet reflector to rotate in space, so that the normal of the symmetry plane of the bifacet reflector coincides with the propagation direction of the incident beam, and guiding the reflected working beam to output in the reverse direction along the original optical path includes: amplifying the power of the servo drive command and outputting a drive current to the power end of the dual-axis servo turntable; driving the dual-axis servo turntable to rotate the bifacet reflector in a spatial orthogonal axis system to eliminate the attitude deviation data; receiving the reflected working beam at the first reflecting surface of the bifacet reflector to generate an intermediate beam, and guiding the intermediate beam to the second reflecting surface for secondary reflection to synthesize an outgoing beam parallel to the incident beam.

[0015] Based on the same inventive concept, this invention also provides an automatic tracking system for a two-sided corner reflector based on incident light angle detection. The system includes: a beam separation module for receiving an externally input incident beam, performing beam splitting on the incident beam to separate a probe beam and a reflective working beam; a photoelectric detection module, optically connected to the beam separation module, for acquiring the optical distribution information of the probe beam, extracting the position offset from the optical distribution information, and generating spot position coordinate data; and a main control calculation module, electrically connected to the photoelectric detection module, for converting the spot position coordinate data and calculating the incident light direction angle data of the incident beam relative to the system reference frame; based on the incident light angle... The attitude is calculated by mapping the optical direction angle data with the spatial geometry of the bifaceted corner reflector, generating target attitude angle data for adjusting the bifaceted corner reflector; the target attitude angle data is compared with the currently acquired actual attitude feedback data to calculate the attitude deviation data, and servo drive commands are generated based on the attitude deviation data; the servo drive module, electrically connected to the main control calculation module, is used to receive and execute the servo drive commands and output power to drive the actuator to rotate; the bifaceted corner reflector module is fixed on the actuator of the servo drive module and is used to follow the rotation so that the normal of the symmetry plane coincides with the propagation direction of the incident beam, and to receive the reflected working beam and output it in the reverse direction along the original optical path.

[0016] Compared with the prior art, the present invention has the following advantages: This invention drives the movement of the bifacial reflector in real time based on the incident light direction detection result, and can automatically complete the pose adjustment by following the changing incident light direction without manual pre-alignment.

[0017] This invention enables the bifaceted corner reflector to always operate in an orientation where the normal of the symmetry plane coincides with the propagation direction of the incident beam, thus fully utilizing the effective reflection aperture of the reflected working beam and improving the energy utilization rate of the beam returning along the original path.

[0018] This invention employs a simple bi-faceted corner reflector in conjunction with a dual-axis servo turntable to perform the task of reversing spatial beams, achieving the return of incident beams in three-dimensional space along their original path with relatively low device costs.

[0019] This invention dynamically adjusts the proportional coefficient and integral coefficient based on the rate of change of attitude deviation, taking into account both the response speed when the incident light direction changes drastically and the tracking accuracy when the direction stabilizes. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating an automatic tracking control method for a bifacial corner reflector based on incident light angle detection, according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the spot position detection of the four-quadrant detector according to an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of grayscale centroid detection of an area array sensor according to an embodiment of the present invention.

[0023] Figure 4 This is a diagram showing the relationship between the incident angle calculation and the attitude angle mapping in an embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the structure of an automatic tracking system for a two-sided corner reflector based on incident light angle detection, according to an embodiment of the present invention.

[0025] Figure 6 This is a framework diagram of an automatic tracking system for a bifacial corner reflector based on incident light angle detection, according to an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Reference Figure 1 One embodiment of the present invention proposes an automatic tracking control method for a bifacial corner reflector based on incident light angle detection. The method employs a closed-loop tracking approach that samples the incident light beam and calculates the incident light direction angle, thereby driving a dual-axis servo turntable to adjust the bifacial corner reflector's pose in real time. Under conditions of dynamic changes in the incident light direction, the method can automatically make the normal of the bifacial corner reflector's symmetry plane coincide with the propagation direction of the incident light beam, guiding the reflected working beam to be output in the reverse direction along the original optical path.

[0028] The method described in this embodiment specifically includes: S1. Receive an externally input incident beam, perform beam splitting on the incident beam, and separate the probe beam and the reflected working beam. In one embodiment of the present invention, step S1 includes the following steps: It receives the incident light beam from the outside, extracts the frequency band of stray light from the environment, and transmits the light beam at the target working wavelength. The target working wavelength beam is guided into the beam splitting medium, and the target working wavelength beam is divided into a first energy beam and a second energy beam according to the beam splitting energy ratio. The first energy beam is converged to form a detection beam, and the second energy beam is guided to be projected onto the bifacial reflector to form a reflective working beam.

[0029] Specifically, the stage of receiving the externally input incident light beam plays a crucial role in establishing communication between the system and external optical signals. The externally input incident light beam refers to a parallel beam that arrives at the system's input port from a distant laser source or propagates through free space. In free-space optical communication and laser ranging scenarios, it typically appears as a narrow-spectrum beam with wavelengths in the visible to near-infrared range. When this beam enters the system, it often carries stray ambient light from sources such as solar radiation, background illumination, and atmospheric scattering. This stray light has a wide spectral distribution, creating background interference in subsequent photoelectric detection stages and reducing the signal-to-noise ratio of the effective signal. To eliminate this interference, it is necessary to extract the ambient stray light frequency band and transmit the target working wavelength beam. This extraction is performed by a narrow-band interference filter. The ambient stray light frequency band refers to the spectral energy that deviates from the system's nominal working wavelength, while the target working wavelength beam refers to the beam whose wavelength falls near the center of the filter's passband and can pass through smoothly. The transmission characteristics of the narrow-band interference filter can be described by the relationship between transmittance and wavelength, and its transmittance function is written as: , in wavelength The transmittance at a given point is a dimensionless ratio, and its value range is [range missing]. to ; The peak transmittance at the center of the passband is a dimensionless ratio, and its value is determined based on the coating process level. This value comes from the measured transmission performance of multilayer dielectric film filters in the visible light band. The wavelength is the center wavelength of the filter's passband, measured in nanometers, and is consistent with the system's operating wavelength. It is used in visible light ranging scenarios. nanometer; The characteristic parameter characterizing the passband width, with dimensions in nanometers, is related to the full width at half maximum (FWHM) of the filter. Between satisfy When half-height and full width are taken At the nanometer level, this value balances high transmittance for the target wavelength with strong suppression of stray light. This bandwidth is based on the common specifications for narrowband filters in laser ranging. After passing through the filter, wavelengths far from the target wavelength are effectively filtered. Stray light with a transmittance close to zero is filtered out, allowing only the target working wavelength beam to be transmitted and output.

[0030] After the target working wavelength beam is transmitted, it needs to be guided into a beam-splitting medium to divide the beam into a first-energy beam and a second-energy beam according to the splitting energy ratio. The beam-splitting medium refers to a medium that... A beam splitter placed at an angle in the optical path has a coating that partially reflects and partially transmits incident light. The beam splitting energy ratio refers to the ratio of incident light energy distributed by the beam splitter to its two branches. The first energy beam is the branch with a smaller energy proportion, used for angle detection, and the second energy beam is the branch with a larger energy proportion, used for reflection. Let the total power of the beam entering the beam splitter at the target wavelength be... The ratio of spectral energy is denoted as The power of the first energy beam With the power of the second energy beam satisfy: , , in The beam power at the target operating wavelength entering the beam-splitting medium, measured in watts; The power of the first energy beam is measured in watts. The power of the second energy beam is measured in watts. The ratio of spectral energies is a dimensionless ratio, and is taken as... That is, the power ratio of the first energy beam to the second energy beam is Compare This ratio is set based on the fact that the detection branch only needs a small amount of light energy to form a recognizable light spot on the photodetector, while the majority of the light energy is reserved for the reflection working branch to ensure the intensity of the beam returning from the original path, thereby achieving a balance between detection sensitivity and return light efficiency.

[0031] After energy separation, the first energy beam is converged to form a probe beam, and the second energy beam is guided to be projected onto the bifacet reflector to form a reflective working beam. The first energy beam, after leaving the beam-splitting medium, remains divergent or parallel and needs to be converged into a small spot by a collimating and focusing lens group. This converged beam is the probe beam, carrying information about the incident light direction and serving as the information carrier for subsequent angle calculations. The second energy beam, without convergence, is directly projected along the optical path onto the incident surface of the bifacet reflector, forming the reflective working beam. This reflective working beam is the target beam that will ultimately be output along the original optical path in reverse. Thus, the incident beam is separated into a probe beam for direction sensing and a reflective working beam for return along the original path, providing input for subsequent steps.

[0032] For example, suppose the wavelength of the externally input incident beam is... Nanoparticles, after entering the system, are first processed by a narrow-band interference filter. The peak transmittance of the filter is then measured. passband center wavelength Nanometers, full width at half maximum (FWHM) Nanometers, then the passband characteristic parameters Nanometers. For wavelengths that are exactly... Substituting the target wavelength beam at the nanometer level into the transmittance function yields... This indicates that the target wavelength beam is... The transmittance allows for smooth passage. For wavelengths of... Nanoscale environmental stray light, substituting into The value of this index term approaches zero, and the transmittance is approximately This verified the effect of effectively suppressing the ambient stray light frequency band while allowing the target working wavelength beam to be transmitted.

[0033] The power of the target working wavelength beam after transmission is set to milliwatts, entering The spectral dispersive medium is placed at a certain angle, and the proportion of spectral energy is taken. First energy beam power milliwatts, second energy beam power milliwatts, the two added together are The milliwatts, equal to the input power, verified the energy distribution relationship under the set spectral energy ratio. The milliwatt-level first-energy beam is converged by a collimating and focusing lens group to form a detection beam. A milliwatt second energy beam is projected onto a bifaceted corner reflector to form a reflected working beam.

[0034] S2. Acquire the optical distribution information of the probe beam, extract the position offset from the optical distribution information, and generate spot position coordinate data; In one embodiment of the present invention, step S2 includes the following steps: The probe beam is received and projected onto different quadrant regions of the photoelectric sensing plane to generate weak photoelectric signals corresponding to each quadrant region. Amplify and filter the high-frequency noise components in the weak photoelectric signal to output a simulated light spot intensity signal; The simulated light spot intensity signal is converted into a digital quantity, and coordinate mapping is performed based on the ratio of the digital quantity difference in each quadrant region to generate light spot position coordinate data.

[0035] Specifically, such as Figure 2 As shown, the detector beam receives and projects onto different quadrant regions of the photosensitive plane, generating weak photoelectric signals corresponding to each quadrant region. The photosensitive plane refers to the photosensitive surface of the four-quadrant detector, which is divided into four independent photosensitive units of equal area by two mutually orthogonal dividing slits, i.e., different quadrant regions, conventionally labeled as quadrant 1, quadrant 2, quadrant 3, and quadrant 4 in counter-clockwise order. When the converged detector beam falls onto the photosensitive plane, the light spot simultaneously covers several quadrant regions. The light energy received by each quadrant region is proportional to the area of ​​the light spot falling into that region. Each quadrant region converts its received light energy into an electrical signal, i.e., a weak photoelectric signal. It is called weak because the detector beam only carries a small portion of the total energy of the incident beam; the light flux falling into a single quadrant is limited, and the current after photoelectric conversion is in the microampere or even nanoampere range. The relationship between the photocurrent and the incident light power in each quadrant region is written as: , , in For the first The photocurrent output in each quadrant region has the dimension of amperes; To fall into the first The detection beam power in each quadrant region is measured in watts. The responsivity of the detector at its operating wavelength, measured in amperes per watt, is given for silicon-based detectors. Take at nanometer wavelength Ampere watt, this value is set based on the spectral response curve of silicon optoelectronic devices; subscript , , , These correspond to the first to fourth quadrant regions, respectively.

[0036] After generating weak photoelectric signals in each quadrant, the high-frequency noise components in the weak photoelectric signals are amplified and filtered to output a simulated light spot intensity signal. Because the weak photoelectric signals have extremely small amplitudes and are superimposed with high-frequency noise components from detector dark current fluctuations, circuit thermal noise, etc., the weak photocurrent needs to be converted and amplified into a voltage signal by a transimpedance amplifier circuit, and then filtered by a low-pass filter circuit to remove the high-frequency noise components. High-frequency noise components refer to the disturbance components with frequencies higher than the effective light spot signal bandwidth. The simulated light spot intensity signal refers to the continuous voltage signal with sufficient amplitude and suppressed noise after amplification and filtering. The cutoff frequency of the low-pass filter stage... With the resistor of the filter circuit ,capacitance satisfy: , in The cutoff frequency has the dimension of Hertz; This is a filter resistor, with the dimension of ohms; This is a filter capacitor, with dimensions in rad / F. The cutoff frequency is taken as... Hertz, this value is higher than the signal bandwidth generated by the change of the light spot with the direction of the incident light but lower than the main noise distribution frequency band, and is set according to the trade-off between the tracking system response speed and noise suppression requirements.

[0037] After obtaining the simulated light spot intensity signal, it is converted into a digital signal. Coordinate mapping is then performed based on the ratio of digital differences between quadrant regions to generate light spot position coordinate data. This conversion is performed by an analog-to-digital converter (ADC). The ADC quantizes the continuous simulated light spot intensity signal into discrete digital signals at a fixed sampling rate. Each digital signal represents an integer encoded value corresponding to the light intensity in each quadrant, denoted as […]. , , , The digital difference ratio refers to a normalized ratio constructed using the differences and sums of digital values ​​in the four quadrants. This ratio depends only on the relative position of the light spot on the photosensitive surface and is independent of the total intensity of the incident light, thus eliminating the influence of light intensity fluctuations. Coordinate mapping refers to converting the digital difference ratio into two-dimensional coordinates of the light spot on the photosensitive surface. Let the horizontal coordinate be... The vertical coordinates are According to the quadrant distribution convention, the first and fourth quadrants are located in the positive quadrant. One side, the first quadrant and the second quadrant are located in the positive On one side: , , in Let be the horizontal coordinate of the light spot, with dimensions in millimeters; Let be the coordinates of the vertical direction of the light spot, with dimensions in millimeters; , , , These are numerical quantities in four quadrants, with dimensions of dimensionless integers. This is a coordinate mapping scaling factor, with dimensions in millimeters, used to convert dimensionless digital quantity differences into actual coordinates with length dimensions. Its value is equal to the equivalent radius of the light spot. The millimeter value, determined based on the detector's effective photosensitive radius and spot size, is the coefficient that makes the dimensions of the right-hand side of the equation consistent with those of the left-hand side, both being millimeters. The fused result... and Together they constitute the coordinate data of the light spot position.

[0038] For example, suppose the converged detection beam falls on the photosensitive surface of a four-quadrant detector, and the digital quantities of the four quadrant regions, after analog-to-digital conversion, are respectively... , , , Coordinate mapping scaling factor Millimeters. First, calculate the sum of the digits in the four quadrants. Horizontal digital difference Substituting the horizontal coordinates, we get Millimeters. Vertical digital difference. Substituting into the vertical coordinate mapping yields Millimeters. The fused spot position coordinates are in the horizontal direction. millimeters, vertical direction approximately The result, measured in millimeters, does not drift with changes in the total power of the probe beam, verifying the immunity of coordinate mapping based on the digital difference ratio to light intensity fluctuations.

[0039] In one embodiment of the present invention, step S2 further includes the following steps: The detector beam is received and spatially discretized using an area array photoelectric sensor array, and a digital image matrix containing grayscale distribution information is output. A background noise threshold is set to perform binarization denoising on the digital image matrix to extract the effective spot connected regions; Gray-weighted centroid calculation is performed on the pixels within the effective light spot connected region to calculate the light spot position coordinate data.

[0040] Specifically, such as Figure 3As shown, in addition to the four-quadrant detection method, a probe beam can also be received and spatially discretized using an area array photoelectric sensor array to output a digital image matrix containing grayscale distribution information. An area array photoelectric sensor array refers to an imaging device composed of a large number of photosensitive pixels arranged in rows and columns. Each pixel independently senses the light energy falling on it and outputs the corresponding grayscale value. Spatial discretization sampling refers to acquiring the continuously distributed probe beam point by point according to the row and column positions of the pixels, thereby converting the continuous light field into a discrete set of pixel grayscale values. A digital image matrix refers to a two-dimensional numerical array organized by row and column indices, where the matrix is ​​located at the row and column index. Line number Column elements This represents the grayscale value perceived by the corresponding pixel; the grayscale distribution information is characterized by the varying values ​​of these elements. The grayscale value and the received optical power of the pixel satisfy the following relationship: , in For the first Line number The grayscale value of a column cell is a dimensionless integer. The power of the probe beam falling on this pixel, in watts; The saturation light power of a pixel, in watts, is the light power required to achieve maximum grayscale, calibrated based on the sensor's dynamic range. The quantization bits are dimensionless integers, and the unit is the number of quantization bits. That is, the grayscale value range is to The quantization accuracy is set based on that of commonly used area array sensors; This indicates the rounding operation.

[0041] After obtaining the digital image matrix, a background noise threshold is set to perform binarization denoising on the digital image matrix, extracting the effective light spot connected regions. The background noise threshold refers to the gray-level threshold used to distinguish effective light spot pixels from background noise pixels, denoted as . Binarization denoising refers to classifying pixels with grayscale values ​​higher than a threshold as valid and assigning them a value of 0.5. Pixels with grayscale values ​​not exceeding a threshold are classified as background and assigned a value of [value missing]. The operation. The effective connected region of the light spot refers to the region after binarization, defined by values ​​of... The area formed by connecting adjacent pixels corresponds to the actual location covered by the light spot. The binarization discrimination relation is written as: , in For the binarized first... Line number The values ​​of the columns of pixels are dimensionless integers; background noise threshold. Based on the average gray level of the background area With gray standard deviation according to set up, and All dimensions are dimensionless integers. Using the mean plus three standard deviations can suppress the probability of misjudging background noise to an extremely low level. This value is set based on the statistical law that three standard deviations cover more than 99% of the samples under normal distribution.

[0042] After extracting the effective connected region of the light spot, gray-level weighted centroid calculation is performed on the pixels within the effective connected region to calculate the light spot position coordinates. Gray-level weighted centroid calculation refers to calculating a weighted average of the row and column coordinates of each pixel using its gray-level value as a weight, thereby obtaining the location of the center of the light spot energy distribution. A pixel refers to a pixel within the effective connected region that takes a value of... Each pixel. Let the set of pixels within the effective connected region of the light spot be . The horizontal coordinate of the light spot position coordinate data with vertical coordinates for: , , in Let be the horizontal coordinate of the light spot, with dimensions in millimeters; Let be the coordinates of the vertical direction of the light spot, with dimensions in millimeters; is the grayscale value of a pixel, and its dimension is a dimensionless integer. For pixel column indexing, For each pixel row index, all values ​​are dimensionless integers. Pixel pitch, measured in millimeters, is the physical distance between the centers of adjacent pixels. The millimeter, set according to the pixel size of the area array sensor, converts the dimensionless weighted average index into actual coordinates with length dimensions, making the dimensions of both sides of the equation consistent.

[0043] For example, suppose that in the digital image matrix acquired by the area array photoelectric sensor array, the effective spot connected region extracted after background noise thresholding and denoising contains three pixels, and their row and column indices and gray values ​​are respectively the first, second, third, fourth, and fifth pixels. Line number grayscale , No. Line number grayscale , No. Line number grayscale Pixel spacing Millimeters. First calculate the total grayscale. Horizontal weighted column index and The horizontally weighted average index is Substituting into Millimeters. Vertical weighted row index and The vertical weighted average index is then... Substituting into Millimeters. The calculated coordinates of the light spot position are approximately in the horizontal direction. millimeters, vertical direction approximately The centroid of the light spot is located at a value of millimeters, with its center of gravity shifted towards the pixel with the higher grayscale value. This verifies the effectiveness of grayscale weighted centroid calculation in reflecting the center of the light spot energy distribution.

[0044] S3. Convert the position coordinate data of the light spot and calculate the incident light direction angle data of the incident light beam relative to the system reference frame; In one embodiment of the present invention, step S3 includes the following steps: Extract the horizontal and vertical axial offsets from the light spot position coordinate data; By combining the focal length parameters of the front optical converging component, the horizontal axial offset is calculated by performing inverse trigonometric function operations to obtain the horizontal azimuth angle data. The vertical pitch angle data is calculated by performing the same inverse trigonometric function operation on the vertical axis offset. The incident light direction angle data is constructed by fusing the horizontal azimuth angle data and the vertical elevation angle data.

[0045] Specifically, such as Figure 4 As shown, the horizontal and vertical axial offsets are extracted from the spot position coordinate data. The spot position coordinate data, provided in the previous step, includes information about the spot's deviation from the geometric center of the photosensitive plane. The horizontal axial offset refers to the distance the spot deviates from the center in the horizontal direction of the photosensitive surface, denoted as... Vertical axial offset refers to the distance the light spot deviates from the center in the vertical direction of the photosensitive surface, denoted as . When the geometric center of the photoelectric sensing plane is the origin of the optical axis, the horizontal axial offset and the vertical axial offset are respectively equal to the horizontal coordinates of the light spot position coordinate data. with vertical coordinates ,Right now , ,in , All dimensions are millimeters.

[0046] After extracting the offset, the horizontal azimuth angle data is calculated by performing inverse trigonometric function operations on the horizontal axis offset, combined with the focal length parameter of the front optical converging component. The front optical converging component refers to a lens group located in front of the detector that converges parallel light incident from different directions to different positions on the focal plane; its focal length parameter is denoted as... The dimension is millimeters. This parameter is determined by the lens group design. Millimeters. According to the imaging principle of geometric optics, the angle between the incident light direction and the optical axis determines the position of the light spot off the optical axis on the focal plane; the two are tangentially related by the focal length. The horizontal azimuth angle refers to the angle between the incident beam and the optical axis of the system reference frame in the horizontal direction, denoted as . The inverse trigonometric function relationship is as follows: , in This is the horizontal azimuth data, measured in degrees. This represents the horizontal axial offset, measured in millimeters. This refers to the focal length parameter of the front optical converging component, measured in millimeters. Because... and Since they have the same dimensions, the ratio of the two is a dimensionless quantity, which is used as the tangent value in the arctangent operation to obtain the angle, and the dimensions are self-consistent.

[0047] In the same manner, the vertical pitch angle data is calculated by performing the same inverse trigonometric function operation on the vertical axis offset. The vertical pitch angle data refers to the angle between the incident beam and the optical axis of the system reference frame in the vertical direction, denoted as... The operational relationship is as follows: , in This is the vertical pitch angle data, measured in degrees; This is the vertical axial offset, measured in millimeters. The focal length parameter of the front optical converging component is measured in millimeters.

[0048] After calculating the horizontal azimuth and vertical elevation angles, the incident light direction angle data is constructed by fusing the horizontal azimuth and vertical elevation angles. Incident light direction angle data refers to a set of data that simultaneously contains information about the angles between the horizontal and vertical directions, and can completely characterize the spatial direction of the incident beam; denoted as... The fusion process involves combining the horizontal azimuth data obtained from separate calculations. With vertical pitch angle data The system is organized into a set of ordered angular quantities that collectively characterize the spatial orientation of the incident beam relative to the system reference frame, serving as input for subsequent attitude calculations.

[0049] For example, let's say the horizontal axial offset is extracted from the spot position coordinate data. millimeters, vertical axial offset Millimeters, focal length parameter of the front optical converging component Millimeters. Perform inverse trigonometric function operations on the horizontal axial offset, first calculating the ratio. Then take the inverse and tangent. Since this ratio is extremely small, its arctangent in degrees is approximately degrees, that is, the horizontal azimuth data is approximately Degree. Perform the same calculation on the vertical axial offset, ratio. Take the original and reverse tangents. degrees, that is, the vertical pitch angle data is approximately Degrees. The incident light direction angle data, constructed by fusing the two, is approximately the horizontal azimuth angle. degrees, vertical pitch angle approximately The result simultaneously characterizes the spatial orientation of the incident beam in both the horizontal and vertical directions, verifying the effectiveness of using inverse trigonometric function calculations to solve for the direction angle by combining focal length parameters.

[0050] S4. Based on the incident light direction angle data and the spatial geometric mapping relationship between the double-sided corner reflector, attitude calculation is performed to generate target attitude angle data for adjusting the double-sided corner reflector. In one embodiment of the present invention, step S4 includes the following steps: The incident light direction angle data is analyzed to separate the horizontal azimuth angle data and the vertical pitch angle data, which represent the incident direction. The horizontal azimuth data is mapped to the first axial target angle of the dihedral reflector rotating around the corresponding common edge. Extract the vertical pitch angle data and perform a 1 / 2 dimension reduction conversion to generate the second axial target angle of the bifaceted corner reflector around the plane perpendicular to the common edge. The first axial target angle and the second axial target angle are combined to generate target attitude angle data.

[0051] Specifically, the incident light direction angle data is analyzed to separate the horizontal azimuth and vertical elevation angle data, which represent the incident direction. The incident light direction angle data is obtained from the previous step by grouping the angles into ordered sets. The form is given, and the analytical process involves reading two components from this ordered set of angles: the horizontal azimuth data. Characterizing the degree to which the incident beam deviates from the optical axis of the system reference frame in the horizontal direction, vertical elevation angle data. Both angular components characterize the degree to which the incident beam deviates from the optical axis of the system reference frame in the vertical direction, and both have the dimension of degrees. The two separated angular components will drive the rotation of the bifaceted corner reflector about two orthogonal axes, respectively.

[0052] After obtaining the horizontal azimuth data, it is mapped to the first axial target angle of the bifaceted reflector's rotation around its corresponding common edge. The bifaceted reflector consists of two mutually perpendicular plane mirrors. The common intersection line formed by the two mirrors is the common edge. The rotation of the bifaceted reflector around this common edge constitutes the first degree of freedom. The first axial target angle refers to the angle the bifaceted reflector needs to reach by rotating around the common edge to allow the incident beam to return along its original path; it is denoted as [missing information]. Based on the original path return condition of the dihedral reflector, the common edge must remain perpendicular to the incident beam in the horizontal projection plane. Therefore, the rotation angle of the dihedral reflector around the common edge should be equal to the horizontal azimuth angle of the incident beam. The mapping relationship is as follows: , in Let be the target angle along the first axis, with the dimension in degrees; The horizontal azimuth angle data is in degrees. The vertical pitch angle data is extracted and subjected to a 1 / 2 dimensionality reduction scaling to generate the target angle of the bifacet reflector around the second axis perpendicular to the plane containing the common edge. The second axis refers to the rotation axis perpendicular to the plane containing the common edge; the rotation of the bifacet reflector around this axis constitutes the second degree of freedom. The 1 / 2 dimensionality reduction scaling refers to multiplying the vertical pitch angle data by... The coefficient is used to calculate the second axial rotation angle. The reason for taking half is because the plane mirror rotates around the axis by an angle... At that time, the direction of its reflected light will change. To ensure that the reflected beam returns precisely along the original optical path in the vertical direction, the rotation angle of the dihedral reflector around the second axis only needs to be half the vertical elevation angle of the incident beam. This ratio is derived from the law of reflection, where the angle of incidence equals the angle of reflection when a plane mirror reflects light. The target angle along the second axis is denoted as... The conversion relationship is as follows: , in The second axial target angle is measured in degrees. This is the vertical pitch angle data, measured in degrees. The target attitude angle data is generated by combining the first and second axis target angles. Target attitude angle data refers to a set of data that simultaneously contains two orthogonal axis rotation angles and can completely describe the spatial attitude that the bifaceted corner reflector should reach; denoted as... The combined action organizes the first axial target angle around the common edge and the second axial target angle around the vertical axis into a set of ordered rotational values, which serve as the target basis for driving the attitude adjustment of the bifacet reflector.

[0053] For example, suppose the incident light direction angle data is separated to obtain the horizontal azimuth angle data. degrees, vertical pitch angle data Degrees. Mapping the horizontal azimuth data to the target angle along the first axis yields... The degree, that is, the dihedral reflector needs to rotate around the common edge. The degree is such that the common edge is perpendicular to the horizontal projection of the incident beam. A 50% dimension reduction scaling operation is performed on the vertical elevation angle data to obtain... The degree, that is, the dihedral reflector needs to rotate about a second axis perpendicular to the plane containing the common edge. Degrees. Combining the two generates the target attitude angle data as the first axis. Degree, second axis This result is consistent with the reflection law that the change in reflected light is twice the angle of rotation, verifying the effectiveness of the half-dimensionality reduction ratio conversion.

[0054] S5. Compare the target attitude angle data with the currently collected actual attitude feedback data, calculate the attitude deviation data, and generate servo drive commands based on the attitude deviation data; In one embodiment of the present invention, step S5 includes the following steps: Read the real-time phase pulses of the position encoding device installed on the rotary actuator and parse out the actual attitude feedback data; By comparing the target attitude angle data with the actual attitude feedback data, the dynamic difference of each motion axis is calculated, and attitude deviation data is generated. The attitude deviation data is input into a preset proportional-integral-derivative control model for control law calculation, and servo drive commands are output.

[0055] Specifically, the real-time phase pulses of the position encoding device mounted on the rotary actuator are read, and the actual attitude feedback data is extracted. The rotary actuator refers to the mechanical device that carries and drives the bifacial reflector. The position encoding device refers to the sensing element mounted on the rotating shaft of the rotary actuator to measure the actual rotation angle of the shaft; it outputs phase pulses proportional to the rotation angle as the shaft rotates. The real-time phase pulses refer to the electrical pulse signals output sequentially by the position encoding device as the shaft rotates; the cumulative number of pulses reflects the angle the shaft has rotated. The actual attitude feedback data refers to the current actual rotation angle of the bifacial reflector along the two axes, obtained from the phase pulse analysis, and is denoted as... The analytical relationship between the phase pulse and the actual rotation angle is as follows: , in The actual rotation angle is obtained from the phase pulse analysis, and its dimension is degrees; This represents the cumulative number of phase pulses output by the position encoding device, and is a dimensionless integer. This represents the total number of pulses output per full revolution of the position encoding device's shaft, a dimensionless integer. That is, the output per full revolution Each pulse represents a pulse. The resolution is set according to the line count specification of the high-precision photoelectric encoder; numerical value This represents the degree measure corresponding to a complete circle. (The right side of the equation...) It is a dimensionless ratio. Multiplying it by the full circle in degrees gives the angle in degrees, with consistent dimensions.

[0056] After parsing the actual attitude feedback data, the target attitude angle data is compared with the actual attitude feedback data to calculate the dynamic difference along each motion axis, generating attitude deviation data. The target attitude angle data, provided in the previous step, represents the attitude the bifacial reflector should reach. The dynamic difference refers to the difference between the target rotation angle and the actual rotation angle along the same axis of motion. Attitude deviation data refers to a set of data composed of the dynamic differences along two axes of motion, characterizing the degree to which the current attitude of the bifacet reflector deviates from the target attitude. This is denoted as... The calculation relationship is as follows: , , in The first axial attitude deviation is measured in degrees. The second axial attitude deviation is measured in degrees. , These are the two components of the target attitude angle data, with the dimension being degrees; , These are the two components of the actual attitude feedback data, with the dimension being degrees.

[0057] The attitude deviation data is input into a preset proportional-integral-derivative (PID) control model for control law calculation, and servo drive commands are output. The PID model refers to a control model that comprehensively utilizes the current value, cumulative value, and rate of change of the deviation to generate the control quantity. Control law calculation refers to the process of obtaining the control quantity by calculating the attitude deviation data based on the PID model. The servo drive command refers to the signal used as the control quantity output to command the rotary actuator. Taking the first axis as an example, the control law calculation relationship is as follows: , in This is the first axial servo drive command, measured in volts. Let be a function of the first axial attitude deviation as a function of time, with the dimension being degrees; Time, measured in seconds; Let be the integral variable, with the dimension being seconds; This is the proportionality constant, with the dimension of volts per degree. ; Let be the integral coefficient, with dimensions in volts per degree per second, and take . ; Here are the differential coefficients, with dimensions in volts per second per degree. The values ​​of the three coefficients are determined based on the rotational inertia and response bandwidth of the dual-axis servo turntable.

[0058] For example, let the target attitude angle data of the first axis be... The position encoding device accumulates and outputs phase pulses along the first axis. Number of pulses per revolution The number of revolutions corresponding to the cumulative pulses here has been converted to the actual rotation angle. For ease of explanation, we take the equivalent calculation within a single loop and let the actual rotation angle be obtained analytically. Degree. First axial attitude deviation. Substitute this deviation into the proportional term of the control law solution and take the proportional coefficient. For every volt per degree, a proportional contribution is obtained. Volt; assuming this deviation has persisted The time interval is approximately constant, and the integral term is... Take the integral coefficient volts per degree per second, Volts; Assume the rate of change of the deviation within the current sampling interval is per second. Degree, differential term Take the differential coefficients volt-seconds per degree, The sum of the three terms yields the first axial servo drive command. The command decreases as the attitude deviation decreases, verifying the convergent adjustment effect of the proportional-integral-derivative (PID) control model on the deviation.

[0059] S6. Execute the servo drive command to drive the bifacial reflector to rotate in space, so that the normal of the symmetry plane of the bifacial reflector coincides with the propagation direction of the incident beam, and guide the reflected working beam to be output in the opposite direction along the original optical path.

[0060] In one embodiment of the present invention, step S6 includes the following steps: By monitoring the rate of change of the attitude deviation data, dynamic feature variables characterizing the degree of change in beam movement are extracted; The proportional coefficient and integral coefficient in the proportional-integral-derivative (PID) adjustment model are dynamically adjusted based on the dynamic characteristic variables to generate an updated PID model. Amplify the power of the servo drive command and output the drive current to the power end of the dual-axis servo turntable; The dual-axis servo turntable is driven to rotate the bifaceted corner reflector in a spatial orthogonal axis system, thereby eliminating the attitude deviation data. The reflected working beam is received and initially reflected at the first reflecting surface of the bifacial reflector to generate an intermediate beam, which is then guided to the second reflecting surface for secondary reflection to synthesize an outgoing beam parallel to the incident beam.

[0061] Specifically, the rate of change of attitude deviation data is monitored to extract dynamic feature variables characterizing the degree of change in beam movement. The attitude deviation data, provided in the previous step, represents the dynamic difference between two motion axes. The rate of change is the ratio of the change in attitude deviation data between adjacent sampling times to the sampling time interval, reflecting how quickly the attitude deviation changes over time. The dynamic feature variable is a quantity extracted from the rate of change of attitude deviation to characterize the severity of the incident beam's directional movement, denoted as... Taking the first axis as an example, the calculation relationship of the dynamic characteristic variables is as follows: , in It is a dynamic characteristic variable, with the unit of measurement being degrees per second; The first axial attitude deviation at the current sampling moment is expressed in degrees. The first axial attitude deviation at the previous sampling time is expressed in degrees. The sampling time interval is expressed in seconds. The time is set according to the sampling period of the control system.

[0062] The proportional and integral coefficients in the proportional-integral-derivative (PID) control model are dynamically adjusted based on dynamic characteristic variables to generate an updated PED model. When the dynamic characteristic variables are large, it indicates a sharp shift in the incident beam direction, requiring an increase in the proportional coefficient to accelerate the response and a moderate decrease in the integral coefficient to suppress overshoot. When the dynamic characteristic variables are small, it indicates a more stable incident beam direction, requiring a decrease in the proportional coefficient to improve steady-state smoothness and an increase in the integral coefficient to eliminate steady-state deviation. The relationship between the proportional and integral coefficients and the adjustment of the dynamic characteristic variables is as follows: , , in The updated proportionality coefficient, in units of volts per degree; The updated integral coefficients are in units of volts per degree per second. This is the baseline value for the proportionality coefficient, with the unit being volts per degree. ; The reference value for the integral coefficient is in volts per degree per second. ; To adjust the gain proportionally, the dimension is volt-seconds per degree squared, take... ,make The dimension is volt-second per degree squared multiplied by degree per second to get volt-second per degree. Consistent; To adjust the gain for integration, the unit is seconds per degree. ,make Since it is a dimensionless quantity, the denominator is guaranteed to be dimensionless. Dimensions and The two gain values ​​are consistent and are obtained by a trade-off between tracking speed and steady-state accuracy.

[0063] The updated proportional-integral-derivative (PID) control model is used to recalculate the control law based on the current attitude deviation data, generating servo drive commands. The recalculation involves using the updated proportional coefficients. With integral coefficient The original coefficients are replaced, and the current attitude deviation data is recalculated according to the control law to obtain a servo drive command that adapts to the current degree of change in beam movement.

[0064] The power of the servo drive command is amplified, and the output drive current is sent to the power end of the dual-axis servo turntable. The servo drive command is a voltage signal with a relatively small amplitude, insufficient to directly drive the motor rotation; therefore, its power needs to be increased by a power amplifier circuit. A dual-axis servo turntable refers to a mechanical platform with two orthogonal rotation axes, capable of supporting and driving the spatial rotation of a bifaceted corner reflector. The power end refers to the motor windings on the dual-axis servo turntable that receive the drive current. The relationship between the drive current and the servo drive command is as follows: , in The drive current output to the power end of the dual-axis servo turntable is measured in amperes. This is a servo drive command, measured in volts. Let be the transconductance gain of the power amplifier circuit, with dimensions in amperes per volt. The settings are based on the matching of the power amplifier and the motor's rated current.

[0065] A dual-axis servo turntable drives a bifaceted corner reflector to rotate along two orthogonal axes in space, eliminating attitude deviation data. This rotation refers to the bifaceted corner reflector simultaneously adjusting its attitude around two mutually orthogonal axes. When the dual-axis servo turntable rotates the bifaceted corner reflector to the attitude corresponding to the target attitude angle data under the action of the driving current, the actual attitude feedback data gradually approaches the target attitude angle data, and the attitude deviation data between the two approaches zero, meaning the attitude deviation data is eliminated.

[0066] The received reflected working beam undergoes initial reflection at the first reflecting surface of the bihedral reflector to generate an intermediate beam. This intermediate beam is then guided to the second reflecting surface for secondary reflection, merging into an outgoing beam parallel to the incident beam. The first and second reflecting surfaces refer to the two mutually perpendicular plane mirrors constituting the bihedral reflector. The reflected working beam is obtained by beam splitting in step S1 and projected onto the bihedral reflector. The intermediate beam refers to the beam of the reflected working beam after initial reflection at the first reflecting surface, which then travels to the second reflecting surface. The outgoing beam refers to the beam of the intermediate beam after secondary reflection at the second reflecting surface, which then exits the bihedral reflector. Based on the composite reflection characteristics of light when the two mirrors are perpendicular, the beam's propagation direction is reversed after two reflections, resulting in the outgoing beam being parallel to the incident beam despite their opposite directions. Let the angle between the propagation direction of the incident beam within the working plane of the bihedral reflector and the reference axis be θ. After being reflected twice by the first and second reflecting surfaces, the direction angle of the emitted beam is... satisfy: , in Let be the incident beam direction angle, with dimensions in degrees; The direction angle of the emitted beam, in degrees; numerical value This represents the amount of direction reversal caused by two perpendicular reflections, measured in degrees. The degree indicates that the emitted beam is output in the reverse direction along the original optical path.

[0067] For example, suppose the first axial attitude deviation at the current sampling time is... Degree, attitude deviation at the previous sampling time Degree, sampling time interval Seconds. Dynamic feature variables. Degrees per second. Substitute the dynamic characteristic variables into the proportional coefficient adjustment relationship and take the baseline value. , proportional adjustment gain The updated scaling factor is obtained. Volts per degree. Substitute into the integral coefficient adjustment relationship and take the baseline value. Integral adjustment gain The updated integral coefficients are obtained. At volts per degree per second, the proportional coefficient increases while the integral coefficient decreases when the visible beam moves rapidly, which aligns with the adjustment intention of accelerating response and suppressing overshoot. The updated coefficients are used to recalculate the current attitude deviation, and the contribution of the proportional term is... The voltage is increased compared to before the adjustment, resulting in a faster-responding servo drive command. Let this servo drive command be... Volts, take the transconductance gain of the power amplifier circuit Ampere volt, output drive current Anchored to the power end of the dual-axis servo turntable, driving the bifaceted corner reflector to rotate around two orthogonal axes to eliminate attitude deviation data. After the attitude is in place, the reflected working beam undergoes an initial reflection on the first reflecting surface to generate an intermediate beam, which is then reflected a second time on the second reflecting surface to synthesize the output beam. The incident beam direction angle is set as follows. The direction angle of the emitted beam is then... The angle of reflection is parallel to the direction of the incident beam, which verifies the effectiveness of the double-sided corner reflector in achieving the reverse output of the reflected working beam along the original optical path through two reflections.

[0068] Based on the same inventive concept, such as Figure 5 As shown, the present invention also provides an automatic tracking system for a two-sided corner reflector based on incident light angle detection, referring to... Figure 6 The system includes: The beam separation module is used to receive an externally input incident beam, perform beam splitting on the incident beam, and separate the probe beam and the reflected working beam. The photoelectric detection module is optically connected to the beam separation module and is used to collect the optical distribution information of the detection beam, extract the position offset in the optical distribution information, and generate spot position coordinate data. The main control calculation module, electrically connected to the photoelectric detection module, is used to convert the light spot position coordinate data and calculate the incident light direction angle data of the incident beam relative to the system reference frame; based on the incident light direction angle data and the spatial geometric mapping relationship of the bifacial corner reflector, attitude calculation is performed to generate target attitude angle data for adjusting the bifacial corner reflector; the target attitude angle data is compared with the currently acquired actual attitude feedback data to calculate the attitude deviation data, and servo drive commands are generated based on the attitude deviation data; The servo drive module is electrically connected to the main control calculation module and is used to receive and execute the servo drive command and output power to drive the actuator to rotate. The bi-faceted corner reflector module is fixed on the actuator of the servo drive module. It is used to rotate to make the normal of the symmetry plane coincide with the propagation direction of the incident beam, and to receive the reflected working beam and output it in the opposite direction along the original optical path.

[0069] All equivalent changes and modifications made in accordance with the teachings of this invention are still within the scope of this invention. Other embodiments of the invention will be readily apparent to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or conventional techniques in the art not described herein.

Claims

1. An automatic tracking control method for a bifacial corner reflector based on incident light angle detection, characterized in that, The method includes: It receives an externally input incident beam, performs beam splitting on the incident beam, and separates the probe beam from the reflected working beam. The optical distribution information of the probe beam is collected, the position offset in the optical distribution information is extracted, and the spot position coordinate data is generated. The position coordinate data of the light spot are converted, and the incident light direction angle data of the incident light beam relative to the system reference frame is calculated. Based on the incident light direction angle data and the spatial geometric mapping relationship between the bifacial corner reflector, attitude calculation is performed to generate target attitude angle data for adjusting the bifacial corner reflector; The target attitude angle data is compared with the currently acquired actual attitude feedback data to calculate the attitude deviation data, and servo drive commands are generated based on the attitude deviation data. The servo drive command is executed to drive the bifaceted corner reflector to rotate in space, so that the normal of the symmetry plane of the bifaceted corner reflector coincides with the propagation direction of the incident beam, and the reflected working beam is guided to be output in the opposite direction along the original optical path.

2. The automatic tracking control method for a bifacial corner reflector based on incident light angle detection according to claim 1, characterized in that, The process of receiving an externally input incident beam and performing beam splitting on the incident beam to separate the probe beam and the reflected working beam includes: It receives the incident light beam from the outside, extracts the frequency band of stray light from the environment, and transmits the light beam at the target working wavelength. The target working wavelength beam is guided into the beam splitting medium, and the target working wavelength beam is divided into a first energy beam and a second energy beam according to the beam splitting energy ratio. The first energy beam is converged to form a detection beam, and the second energy beam is guided to be projected onto the bifacial reflector to form a reflective working beam.

3. The automatic tracking control method for a bifacial corner reflector based on incident light angle detection according to claim 2, characterized in that, The process of acquiring the optical distribution information of the probe beam, extracting the position offset from the optical distribution information, and generating spot position coordinate data includes: The probe beam is received and projected onto different quadrant regions of the photoelectric sensing plane to generate weak photoelectric signals corresponding to each quadrant region. Amplify and filter the high-frequency noise components in the weak photoelectric signal to output a simulated light spot intensity signal; The simulated light spot intensity signal is converted into a digital quantity, and coordinate mapping is performed based on the ratio of the digital quantity difference in each quadrant region to generate light spot position coordinate data.

4. The automatic tracking control method for a bifacial corner reflector based on incident light angle detection according to claim 2, characterized in that, The step of acquiring the optical distribution information of the probe beam, extracting the position offset from the optical distribution information, and generating spot position coordinate data further includes: The detector beam is received and spatially discretized using an area array photoelectric sensor array, and a digital image matrix containing grayscale distribution information is output. A background noise threshold is set to perform binarization denoising on the digital image matrix to extract the effective spot connected regions; Gray-weighted centroid calculation is performed on the pixels within the effective light spot connected region to calculate the light spot position coordinate data.

5. The automatic tracking control method for a bifacial corner reflector based on incident light angle detection according to claim 3 or 4, characterized in that, The process of transforming the light spot position coordinate data and calculating the incident light direction angle data relative to the system reference frame includes: Extract the horizontal and vertical axial offsets from the light spot position coordinate data; By combining the focal length parameters of the front optical converging component, the horizontal axial offset is calculated by performing inverse trigonometric function operations to obtain the horizontal azimuth angle data. The vertical pitch angle data is calculated by performing the same inverse trigonometric function operation on the vertical axis offset. The incident light direction angle data is constructed by fusing the horizontal azimuth angle data and the vertical elevation angle data.

6. The automatic tracking control method for a bifacial corner reflector based on incident light angle detection according to claim 5, characterized in that, The step of performing attitude calculation based on the incident light direction angle data and the spatial geometric mapping relationship between the bifacial corner reflector, and generating target attitude angle data for adjusting the bifacial corner reflector, includes: The incident light direction angle data is analyzed to separate the horizontal azimuth angle data and the vertical pitch angle data, which represent the incident direction. The horizontal azimuth data is mapped to the first axial target angle of the dihedral reflector rotating around the corresponding common edge. Extract the vertical pitch angle data and perform a 1 / 2 dimension reduction conversion to generate the second axial target angle of the bifaceted corner reflector around the plane perpendicular to the common edge. The first axial target angle and the second axial target angle are combined to generate target attitude angle data.

7. The automatic tracking control method for a bifacial corner reflector based on incident light angle detection according to claim 6, characterized in that, The step of comparing the target attitude angle data with the currently acquired actual attitude feedback data, calculating the attitude deviation data, and generating servo drive commands based on the attitude deviation data includes: Read the real-time phase pulses of the position encoding device installed on the rotary actuator and parse out the actual attitude feedback data; By comparing the target attitude angle data with the actual attitude feedback data, the dynamic difference of each motion axis is calculated, and attitude deviation data is generated. The attitude deviation data is input into a preset proportional-integral-derivative control model for control law calculation, and servo drive commands are output.

8. The automatic tracking control method for a bifacial corner reflector based on incident light angle detection according to claim 7, characterized in that, The step of inputting the attitude deviation data into a preset proportional-integral-derivative (PID) control model for control law calculation and outputting servo drive commands includes: By monitoring the rate of change of the attitude deviation data, dynamic feature variables characterizing the degree of change in beam movement are extracted; The proportional coefficient and integral coefficient in the proportional-integral-derivative (PID) control model are dynamically adjusted based on the dynamic characteristic variables to generate an updated PID control model. The updated proportional-integral-derivative (PID) control model is used to recalculate the control law for the current attitude deviation data, generating servo drive commands.

9. The automatic tracking control method for a bifacial corner reflector based on incident light angle detection according to claim 8, characterized in that, The step of executing the servo drive command to drive the bifaceted corner reflector to rotate in space, so that the normal of the symmetry plane of the bifaceted corner reflector coincides with the propagation direction of the incident beam, and guiding the reflected working beam to output in the opposite direction along the original optical path includes: Amplify the power of the servo drive command and output the drive current to the power end of the dual-axis servo turntable; The dual-axis servo turntable is driven to rotate the bifaceted corner reflector in a spatial orthogonal axis system, thereby eliminating the attitude deviation data. The reflected working beam is received and initially reflected at the first reflecting surface of the bifacial reflector to generate an intermediate beam, which is then guided to the second reflecting surface for secondary reflection to synthesize an outgoing beam parallel to the incident beam.

10. An automatic tracking system for a bifacial corner reflector based on incident light angle detection, characterized in that, The system includes: The beam separation module is used to receive an externally input incident beam, perform beam splitting on the incident beam, and separate the probe beam and the reflected working beam. The photoelectric detection module is optically connected to the beam separation module and is used to collect the optical distribution information of the detection beam, extract the position offset in the optical distribution information, and generate spot position coordinate data. The main control calculation module, electrically connected to the photoelectric detection module, is used to convert the light spot position coordinate data and calculate the incident light direction angle data of the incident beam relative to the system reference frame; based on the incident light direction angle data and the spatial geometric mapping relationship of the bifacial corner reflector, attitude calculation is performed to generate target attitude angle data for adjusting the bifacial corner reflector; the target attitude angle data is compared with the currently acquired actual attitude feedback data to calculate the attitude deviation data, and servo drive commands are generated based on the attitude deviation data; The servo drive module is electrically connected to the main control calculation module and is used to receive and execute the servo drive command and output power to drive the actuator to rotate. The bi-faceted corner reflector module is fixed on the actuator of the servo drive module. It is used to rotate to make the normal of the symmetry plane coincide with the propagation direction of the incident beam, and to receive the reflected working beam and output it in the opposite direction along the original optical path.

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