Automatic focusing measuring device and method for laser interferometer

Abstract

The invention provides an automatic focusing measuring device and method for a laser interferometer, and the device comprises an interference light splitting unit which comprises a laser interferometer and a spectroscope suite which comprises a spectroscope, an optical filter, a slide and a light transmitting hole part, and is used for dividing retroreflection laser into a transmission light path and a refraction light path; the control motion unit comprises a six-degree-of-freedom motion platform, a two-dimensional photosensitive position sensor suite and a single chip microcomputer, and the six-degree-of-freedom motion platform is rigidly connected with the laser interferometer and used for adjusting the pose; and the upper computer is used for receiving light beam offset data detected by the two-dimensional photosensitive position sensor suite, resolving six-degree-of-freedom pose adjustment parameters and driving the six-degree-of-freedom motion platform to calibrate a light path in real time through closed-loop control. According to the invention, the problems of long time consumption and complex operation of manual light focusing of the laser interferometer are solved, and automatic light focusing measurement of the laser interferometer is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic optical alignment measurement, and specifically, to a laser interferometer automatic optical alignment measurement device and a measurement method. Background Art

[0002] At present, there is no mature laser interferometer automatic optical alignment device on the market, and the optical alignment of the laser interferometer still relies on manual optical alignment by operators. The optical path calibration process is relatively difficult, requiring repeated adjustments and taking a very long time. It highly depends on the technical level and experience of the operator, resulting in a significant reduction in detection efficiency.

[0003] Chinese Patent with the application number 201811112040.X discloses "A High-Efficiency and Precise Calibration Method for the Optical Path of a Laser Interferometer Based on PSD". Although this method has utilized a two-dimensional photosensitive position sensor (PSD) as the core technology to achieve automatic calibration of the optical path of the laser interferometer by capturing beam offset data, in the patent literature, there is no description of the structure of the automatic interferometer pose adjustment device for implementing this technology, and no detailed explanation is given on how to use the obtained beam offset data to drive the automatic adjustment process and its underlying algorithm logic.

[0004] Chinese Patent with the application number 201710667421.3 discloses "A Measurement Method for Automatic Optical Alignment of a Laser Interferometer". Although this method has achieved automatic optical alignment of the laser interferometer in the xy plane and the yz plane, it uses a relatively complex algorithm when processing the calculation of the beam offset, which increases the operation burden and complexity of the system to a certain extent. To achieve full in-plane automatic optical alignment, the overall structure design of this device also tends to be complex, which affects the manufacturing cost, maintenance convenience of the device, and its applicability in the application scenario of single-axis positioning error measurement. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a laser interferometer automatic optical alignment measurement device and a measurement method.

[0006] The laser interferometer automatic optical alignment measurement device provided by the present invention includes:

[0007] An interference beam splitting unit, including a laser interferometer and a beam splitter kit. The beam splitter kit includes a beam splitter, a filter, a glass slide, and a light-transmitting hole component, and is used to divide the retro-reflected laser into a transmission optical path and a refraction optical path;

[0008] A control and motion unit, including a six-degree-of-freedom motion platform, a two-dimensional photosensitive position sensor kit, and a single-chip microcomputer. The six-degree-of-freedom motion platform is rigidly connected to the laser interferometer and is used to adjust the pose;

[0009] The host computer is used to receive the beam deviation data detected by the two-dimensional photosensitive position sensor kit, solve the six-degree-of-freedom posture adjustment parameters, and drive the six-degree-of-freedom motion platform to calibrate the optical path in real time through closed-loop control;

[0010] Among them, the spectroscope is tilted and fixed in the spectroscope kit, the transmitted light passes through the glass slide and returns to the laser interferometer for distance measurement, and the refracted light enters the two-dimensional photosensor position sensor kit after passing through the filter and the light-transmitting hole. The coaxial installation ensures that the origin of the light spot of the two-dimensional photosensor position coincides with the origin of the reflected light position.

[0011] Preferably, the motion control of the six-degree-of-freedom motion platform includes:

[0012] Based on the inverse kinematics algorithm, the global coordinate instructions are solved into the independent extension and retraction amounts of the six electric cylinders;

[0013] The servo motor drives the electric cylinder to move in coordination, and the pitch, yaw and roll angles are adjusted through differential telescoping, and three-dimensional translation is achieved through synchronous and equal telescoping.

[0014] The position and angle data are fed back in real time through the grating ruler and inclination sensor, and the PID and feedforward dynamic compensation algorithms are combined to achieve micron-level positioning accuracy and milliradian-level attitude accuracy.

[0015] Preferably, the solving algorithm of the host computer includes:

[0016] According to the deviation signal of the two-dimensional photosensitive position sensor and the interference light intensity data of the laser interferometer, an optical-mechanical coupling optimization model is constructed;

[0017] The 3σ criterion is used to eliminate abnormal data, and the ideal values ​​of the six-degree-of-freedom parameters are calculated by weighted geometric mean, and the weight coefficients are dynamically determined by the light intensity signal-to-noise ratio.

[0018] Preferably, the optical path design of the spectroscope kit satisfies:

[0019] The light-transmitting hole piece acts as an aperture stop, limiting the diameter of the refracted light spot to reduce edge scattering;

[0020] The glass slide compensates for the optical path difference between the transmission light path and the refraction light path, while protecting the beam splitter surface;

[0021] The filter filters out stray light of non-laser wavelengths and improves the signal-to-noise ratio of the two-dimensional photosensitive position sensor signal to a preset threshold.

[0022] Preferably, the signal processing flow of the two-dimensional photosensitive position sensor kit includes:

[0023] After converting the optical signal into an electrical signal, the position digital signal is output through the built-in board;

[0024] The single-chip microcomputer analyzes digital signals and converts them into control instructions for the six-degree-of-freedom platform, which are transmitted to the motion controller via Ethernet.

[0025] Preferably, the laser interferometer is a dual-frequency helium-neon laser interferometer, and its ranging process is based on the heterodyne interference principle and the Doppler frequency shift effect, specifically including:

[0026] Generation of dual-frequency laser and polarization beam splitting;

[0027] Demodulation of the Doppler frequency shift signal caused by the movement of the measurement mirror;

[0028] Phase change counting and real-time compensation of the air refractive index, and correction of the wavelength error through the Euler equation.

[0029] Preferably, the working process of the device further includes:

[0030] Screening valid data by real-time monitoring of the intensity of the interferometer light intensity signal and the phase continuity characteristics;

[0031] When the light intensity fluctuation satisfies the preset range and there is a phase jump, record the corresponding pose parameters;

[0032] Combining dynamic trajectory sampling and statistical optimization to determine the optimal working point for maintaining the stability of the interference field.

[0033] Preferably, the coaxial installation of the beam splitter and the two-dimensional photosensitive position sensor kit is achieved by fine-tuning screws, ensuring that the center of the beam splitter is coaxial with the origin of the two-dimensional photosensitive position sensor kit, with a deviation not exceeding ±10μm.

[0034] Preferably, the pose adjustment target of the six-degree-of-freedom motion platform is:

[0035] Make the intensity of the retroreflected light received by the laser interferometer reach more than 80% of the initial value;

[0036] Through continuous iterative adjustment until the phase of the interference signal is continuous and the light intensity fluctuation converges to the allowable range.

[0037] According to the automatic optical alignment measurement method of the laser interferometer provided by the present invention, it includes the following steps:

[0038] Step 1: Coaxially install the beam splitter and the two-dimensional photosensitive position sensor kit, and calibrate the initial optical path;

[0039] Step 2: The laser interferometer emits measurement laser, which is retroreflected by the corner cube reflector and then split;

[0040] Step 3: Real-time collect the position deviation of the refracted light and the interference light intensity data, and calculate the pose adjustment parameters through the upper computer;

[0041] Step 4: Drive the six-degree-of-freedom motion platform to adjust its pose until the light intensity and phase continuity constraints are satisfied;

[0042] Step 5: Record the optimized pose parameters, complete the automatic light alignment, and start the measurement process.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) By adopting a two-dimensional photosensitive position sensor, the problem of difficult acquisition of the position deviation information of the reflected light of the laser interferometer is solved;

[0045] (2) By adopting a structure in which the two-dimensional photosensitive position sensor and the beam splitter are coaxially connected in series, the problem that the light spot origin of the two-dimensional photosensitive position sensor does not coincide with the position origin of the reflected light is solved;

[0046] (3) By using the upper computer to calculate the beam position offset information and transmitting the data to the motion controller to control the movement of the six-degree-of-freedom platform, the real-time adjustment of the measurement pose during the measurement process of the laser interferometer is realized, the problems of long time consumption and complex operation of manual light alignment of the laser interferometer are solved, and the automatic light alignment measurement of the laser interferometer is realized. Description of the Drawings

[0047] By reading the following detailed description of the non-limiting embodiments with reference to the accompanying drawings, other features, objects, and advantages of the present invention will become more apparent:

[0048] Figure 1 is a schematic structural diagram of an automatic light alignment device for a laser interferometer;

[0049] Figure 2 is a schematic structural diagram of an automatic light alignment device for a laser interferometer;

[0050] Reference numerals: 1 - laser interferometer, 2 - six-degree-of-freedom motion platform, 3 - two-dimensional photosensitive position sensor kit, 4 - beam splitter kit, 5 - beam splitter, 6 - filter, 7 - glass slide, 8 - light-transmitting hole part. Detailed Embodiments

[0051] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0052] Embodiment

[0053] As Figure 1 and Figure 2 , the present invention provides an automatic light alignment device for a laser interferometer, including:

[0054] The interference spectroscopic unit includes a laser interferometer 1 and a beam splitter kit 4. The laser interferometer 1 can emit a helium-neon laser with a wavelength of 633 nm. After passing through a corner cube reflector fixed in the working space of the machine tool, the laser interferometer 1 can receive the retroreflected light and calculate the relative displacement distance.

[0055] The specific process of the dual-frequency laser interferometer calculating the relative displacement distance is based on the heterodyne interference principle and the Doppler frequency shift effect. The core steps are as follows:

[0056] 1. Dual-frequency laser generation and beam splitting

[0057] Laser source: Emits two linearly polarized lights with similar frequencies (f1 and f2, usually the frequency difference is Δf = f1 - f2, such as 1 - 20 MHz).

[0058] Polarizing beam splitter: Separates the two beams of light into a reference light (f1) and a measurement light (f2), which are respectively directed to a fixed reference mirror and a moving measurement mirror.

[0059] 2. Doppler frequency shift and interference of retroreflected light

[0060] Movement of the measurement mirror: When the measurement mirror moves at a speed v, the frequency of the reflected measurement light is frequency-shifted due to the Doppler effect:

[0061]

[0062] where c is the speed of light.

[0063] Interference signal generation: The reference light (f1) and the retroreflected measurement light (f 2′ ) undergo heterodyne interference in the interferometer to form a beat frequency signal:

[0064]

[0065] 3. Signal demodulation and phase detection

[0066] Photoelectric conversion: The beat frequency signal is converted into an electrical signal by a photodetector and enters a phase comparator after amplification and filtering.

[0067] Phase change counting: When the measurement mirror moves a distance ΔL, the phase change amount Δφ satisfies:

[0068]

[0069] where λ is the wavelength of the laser in vacuum (such as for He-Ne laser, λ = 632.8 nm). Each phase period (2π) corresponds to a displacement change of λ / 2.

[0070] 4. Displacement calculation formula

[0071] Counter Accumulation: The number of phase cycles N is recorded by an electronic counter, and the displacement is calculated as follows:

[0072]

[0073] In the formula: n: Air refractive index (which needs to be compensated in real time according to environmental temperature, humidity, and air pressure, and the formula is Euler's equation):

[0074]

[0075] P is the air pressure (Pa), T is the temperature (°C), and H is the humidity (%).

[0076] 5. Dual - frequency Anti - interference Mechanism

[0077] Common - mode Noise Suppression: The dual - frequency beat signal is insensitive to common - mode interferences such as temperature drift and mechanical vibration, and only responds to the frequency shift caused by the movement of the measurement mirror.

[0078] Dynamic Compensation: By measuring environmental parameters in real time to correct the refractive index n, ensure the accuracy of the wavelength λ air = λ / n.

[0079] The beam splitter kit 4 includes a beam splitter 5, a filter 6, a glass slide 7, and a light - transmitting hole component 8. Beam splitter 5: Divides the retro - reflected laser into transmitted light (returning to the interferometer for distance measurement) and refracted light (guiding to the two - dimensional photosensitive position sensor to detect the position deviation) in proportion. Filter 6: Filters out stray light of non - laser wavelengths, improving the signal - to - noise ratio of the two - dimensional photosensitive position sensor. Glass slide 7: Protects the surface of the beam splitter from contamination and compensates for the optical path difference of the transmitted / refracted light paths. Light - transmitting hole component 8: Limits the spot size and locates the reference, ensuring accurate detection of the spot position by the two - dimensional photosensitive position sensor. The beam splitter 5 is fixed inside the beam splitter kit 4 by optical resin, used to split the retro - reflected light into two paths, the transmitted light returns to the laser interferometer 1 for interference distance measurement, and the refracted light enters the control motion unit for feedback control.

[0080] The control motion unit includes a two - dimensional photosensitive position sensor kit 3, a six - degree - of - freedom motion platform 2, and a single - chip microcomputer. The two - dimensional photosensitive position sensor kit 3 has a built - in signal processing circuit, which can analyze the deviation of the refracted light in the interference beam splitting unit and transmit it to the single - chip microcomputer through a signal line. The single - chip microcomputer processes the obtained control signal through a built - in algorithm and controls the pose adjustment of the six - degree - of - freedom motion platform 2 through a network cable to achieve automatic optical alignment.

[0081] The laser interferometer 1 is fixed to the top of the six-degree-of-freedom motion platform 2, and the two are rigidly connected through a mechanical interface or a special fixture. The beam splitter kit 4 is installed in front of the laser output port of the laser interferometer 1 and is fixed to the housing of the laser interferometer 1 by threads or snaps to ensure that the optical axis is coaxial with the laser output direction. Beam splitter 5: Fixed at a 45° tilt inside the kit, it divides the retroreflected light into transmitted light that returns to the interferometer and refracted light that enters the two-dimensional photosensitive position sensor kit 3. Filter 6: Located downstream of the refraction optical path of the beam splitter 5 to filter out stray light. Light-transmitting hole part 8: Adjacent to the filter 6, it is an aperture stop that limits the diameter of the refracted light spot and reduces edge scattering. Glass slide 7: Located in the transmitted optical path of the beam splitter 5 to protect the surface of the beam splitter and assist the transmitted light to return to the interferometer. The two-dimensional photosensitive position sensor kit 3 is located at the end of the refraction optical path of the beam splitter kit 4 and is aligned with the refraction direction of the beam splitter 5. The two-dimensional photosensitive position sensor kit 3 has a built-in signal processing circuit that transmits to the six-degree-of-freedom motion platform 2.

[0082] The working process of the cooperation between software and hardware:

[0083] Step 1: Install the beam splitter 5 coaxially with the two-dimensional photosensitive position sensor kit 3, and by adjusting the fine-tuning screw, make the center of the beam splitter coaxial with the origin of the two-dimensional photosensitive position sensor;

[0084] Step 2: Install the corner cube reflector on the machine tool spindle, and control the machine tool spindle to be as close as possible to the measuring device. Adjust the Y / Z axis position of the machine tool spindle so that the laser interferometer can receive the reflected light at the initial moment;

[0085] Step 3: The laser interferometer 1 emits measuring laser, and the measuring laser is retroreflected by the corner cube reflector to generate retroreflected light;

[0086] Step 4: The retroreflected light passes through the beam splitter 5 fixed in the beam splitter kit 4 and is divided into two paths. One path is the transmitted light, which passes through the glass slide 7 and returns to the laser interferometer 1 for interference ranging; the other path is the refracted light, which passes through the light-transmitting hole part 8 and enters the two-dimensional photosensitive position sensor 5 in the interference beam splitting unit.

[0087] Step 5: The two-dimensional photosensitive position sensor 5 detects the two-dimensional deviation of the refracted light in the measurement plane, converts the optical signal into an electrical signal, outputs a position digital signal through the built-in board, and transmits it to the single-chip microcomputer through a signal line;

[0088] Step 6: The single-chip microcomputer analyzes the position digital signal and outputs a control signal through the geometric relationship between the device and the machine tool;

[0089] Step 7: The six-degree-of-freedom motion platform 2 receives the control signal through the network cable, and adjusts the device's posture by modifying the pitch angle and horizontal and vertical positions: the host computer sends the target posture parameters (including three-dimensional translation and rotation angle) through Ethernet, and the platform controller uses the inverse kinematics algorithm to solve the global coordinate instructions into the independent extension and contraction of the six electric cylinders; then, the servo motor drives the electric cylinders to move in coordination - the pitch / yaw / roll angle adjustment is achieved through asymmetric extension and contraction (such as the differential extension and contraction of the diagonal electric cylinders to generate torque), and the X / Y / Z translation is completed by synchronous equal extension and contraction (assisted by Z-direction compensation to maintain the flatness of the platform); during the movement, the grating scale and the inclination sensor feedback the position and angle data in real time, and the closed-loop control is combined with the dynamic compensation algorithm (PID+feedforward) to correct the error, and finally achieve micron-level positioning and milliradian-level posture accuracy to meet the needs of high-precision optical alignment or precision manufacturing. The quality of the return light received by the laser interferometer reaches 80%;

[0090] Step 8: Move the corner reflector, the six-degree-of-freedom platform obtains a series of posture parameters, and determines a set of ideal parameters based on the interferometer light intensity information. The determination of the ideal parameters can be expressed as: dynamic trajectory sampling and statistical optimization process under the continuity constraint of the interference signal. During the motion calibration process driven by the six-degree-of-freedom platform, the interferometer light intensity signal intensity I(t) and phase continuity characteristics are monitored in real time to construct a valid data screening criterion: if and only if the light intensity fluctuation satisfies |ΔI(t) / I avg |≤1% and the phase jump Δφ(t)<π / 2 (excluding the unlocked state), synchronously record the platform posture parameter P at the corresponding time i =[x i ,y i ,z i ,θ xi ,θ yi ,θ zi ]. Then, the N sets of parameter sets that meet the conditions are robustly processed:

[0091] 1) Use the 3σ criterion to eliminate outliers in the motion trajectory;

[0092] 2) Calculate the weighted geometric mean of the six degrees of freedom parameters:

[0093]

[0094] Among them, the weight coefficient w k The light intensity signal-to-noise ratio SNR at the corresponding time k Dynamically determined, that is, w k =erf(SNR k / 30) (error function normalization). This method extracts the optimal operating point in the parameter space that maintains the stability of the interference field through the correlation of opto-mechanical coupling characteristics. Compared with the simple arithmetic mean, it can reduce the influence of mechanical nonlinear errors on parameter estimation. Thus, it ensures that the interferometer remains continuously illuminated throughout the measurement process.

[0095] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0096] Those skilled in the art know that in addition to implementing the systems, devices, and their respective modules provided by the present invention in the form of pure computer-readable program codes, the method steps can be logically programmed to enable the systems, devices, and their respective modules provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. Therefore, the systems, devices, and their respective modules provided by the present invention can be considered as a kind of hardware component, and the modules included therein for implementing various programs can also be regarded as the structure within the hardware component; the modules for implementing various functions can also be regarded as both software programs for implementing the method and the structure within the hardware component.

[0097] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other.

Claims

1. An automatic optical alignment measurement device for a laser interferometer, characterized in that, include: An interference spectrometer unit comprises a laser interferometer (1) and a spectroscope kit (4), wherein the spectroscope kit (4) comprises a spectroscope (5), a filter (6), a glass slide (7) and a light-transmitting hole (8), and is used to split the reflected laser light into a transmission light path and a refraction light path; A control motion unit comprises a six-degree-of-freedom motion platform (2), a two-dimensional photosensitive position sensor kit (3) and a single-chip microcomputer, wherein the six-degree-of-freedom motion platform (2) is rigidly connected to the laser interferometer (1) for adjusting the position and posture; The host computer is used to receive the beam deviation data detected by the two-dimensional photosensitive position sensor kit (3), calculate the six-degree-of-freedom posture adjustment parameters, and drive the six-degree-of-freedom motion platform (2) to calibrate the optical path in real time through closed-loop control; The beam splitter (5) is tilted and fixed in the beam splitter kit (4), the transmitted light passes through the glass slide (7) and returns to the laser interferometer (1) for distance measurement, and the refracted light passes through the filter (6) and the light-transmitting hole (8) and enters the two-dimensional photosensitive position sensor kit (3), and the coaxial installation ensures that the light spot origin of the two-dimensional photosensitive position sensor coincides with the reflected light position origin.

2. The laser interferometer automatic optical alignment measuring device according to claim 1, characterized in that, The motion control of the six-degree-of-freedom motion platform (2) includes: Based on the inverse kinematics algorithm, the global coordinate instructions are solved into the independent extension and retraction amounts of the six electric cylinders; The servo motor drives the electric cylinder to move in coordination, and the pitch, yaw and roll angles are adjusted through differential telescoping, and three-dimensional translation is achieved through synchronous and equal telescoping. The position and angle data are fed back in real time through the grating ruler and inclination sensor, and the PID and feedforward dynamic compensation algorithms are combined to achieve micron-level positioning accuracy and milliradian-level attitude accuracy.

3. The laser interferometer automatic optical alignment measuring device according to claim 1, wherein The solving algorithm of the host computer includes: According to the deviation signal of the two-dimensional photosensitive position sensor (3), combined with the interference light intensity data of the laser interferometer (1), an optical-mechanical coupling optimization model is constructed; The 3σ criterion is used to eliminate abnormal data, and the ideal values ​​of the six-degree-of-freedom parameters are calculated by weighted geometric mean, and the weight coefficients are dynamically determined by the light intensity signal-to-noise ratio.

4. The laser interferometer automatic optical alignment measuring device according to claim 1, characterized in that, The optical path design of the spectroscope kit (4) satisfies: The light-transmitting hole (8) serves as an aperture stop to limit the diameter of the refracted light spot to reduce edge scattering; The glass slide (7) compensates for the optical path difference between the transmission light path and the refraction light path, while protecting the surface of the beam splitter; The filter (6) filters out stray light of non-laser wavelengths, thereby increasing the signal-to-noise ratio of the two-dimensional photosensitive position sensor signal to a preset threshold.

5. The automatic optical alignment measurement device of a laser interferometer according to claim 1, characterized in that, The signal processing flow of the two-dimensional photosensitive position sensor kit (3) includes: After converting the optical signal into an electrical signal, the position digital signal is output through the built-in board; The microcontroller analyzes the digital signal and converts it into control instructions for the six-degree-of-freedom platform, which are then transmitted to the motion controller via Ethernet.

6. The laser interferometer automatic optical alignment measuring device according to claim 1, wherein The laser interferometer (1) is a dual-frequency helium-neon laser interferometer, and its distance measurement process is based on the heterodyne interference principle and the Doppler frequency shift effect, and specifically includes: Dual-frequency laser generation and polarization splitting; Demodulation of Doppler frequency shift signal caused by the motion of the measuring mirror; Phase change counting and air refractive index real-time compensation, wavelength error correction through Euler equation.

7. The automatic optical alignment measuring device of a laser interferometer according to claim 1, characterized in that The workflow of the device further includes: Filter effective data by real-time monitoring of the interferometer light intensity signal strength and phase continuity characteristics; When the light intensity fluctuation satisfies the preset range and there is a phase jump, record the corresponding pose parameters; Combined with dynamic trajectory sampling and statistical optimization, determine the optimal operating point to maintain the stability of the interference field.

8. The automatic optical alignment measurement device of a laser interferometer according to claim 1, wherein The coaxial installation of the beam splitter (5) and the two-dimensional photosensitive position sensor kit (3) is realized by fine-tuning screws, ensuring that the center of the beam splitter is coaxial with the origin of the two-dimensional photosensitive position sensor kit, and the deviation does not exceed ±10 μm.

9. The laser interferometer automatic optical alignment measuring device according to claim 1, characterized in that, The pose adjustment target of the six-degree-of-freedom motion platform (2) is as follows: Make the intensity of the retroreflected light received by the laser interferometer (1) reach more than 80% of the initial value; Through continuous iterative adjustment until the phase of the interference signal is continuous and the light intensity fluctuation converges to the allowable range.

10. A method for automatically aligning and measuring with a laser interferometer, which is implemented based on the laser interferometer automatic alignment and measurement device according to any one of claims 1-9, characterized in that, It includes the following steps: Step 1: Install the beam splitter (5) and the two-dimensional photosensitive position sensor kit (3) coaxially to calibrate the initial optical path; Step 2: The laser interferometer (1) emits measurement laser, which is retroreflected by the corner cube mirror and then split; Step 3: Real-time collect the position deviation of the refracted light and the interference light intensity data, and calculate the pose adjustment parameters through the upper computer; Step 4: Drive the six-degree-of-freedom motion platform (2) to adjust the pose until the light intensity and phase continuity constraints are satisfied; Step 5: Record the optimized pose parameters, complete the automatic alignment and start the measurement process.

Images