Machine tool precision rapid light correction device and light correction method based on laser interferometer

Abstract

The invention discloses a machine tool precision rapid light correction device and method based on a laser interferometer, and the device comprises an interference light splitting unit which comprises a laser interferometer and a spectroscope suite; the spectroscope suite comprises a spectroscope, the spectroscope is arranged in the spectroscope suite and is used for dividing the retroreflection light into two paths, the transmission light returns to the laser interferometer for interference ranging, and the refracted light enters the control motion unit for feedback control; and the control motion unit comprises a two-dimensional photosensitive position sensor suite, a six-degree-of-freedom motion platform and a single chip microcomputer. According to the invention, the PSD two-dimensional photosensitive position sensor is used for obtaining the position deviation information of reflected light at different measuring point positions; the deviation information is calculated through the upper computer, pose adjustment parameters of the six-degree-of-freedom motion platform are obtained, a set of ideal parameters are determined by combining light intensity information of the interferometer, and therefore it is guaranteed that the interferometer always keeps continuous light in the whole measurement process.

Description

Technical Field

[0001] This application belongs to the field of machine tool precision calibration technology, specifically relating to a rapid machine tool precision calibration device and calibration method based on a laser interferometer. Background Technology

[0002] Currently, there are no mature automatic alignment devices for laser interferometers on the market, and laser interferometer alignment still relies on manual alignment by operators. The optical path calibration process is difficult, requires repeated adjustments, is extremely time-consuming, and heavily depends on the operator's skill level and experience, resulting in a significant reduction in detection efficiency.

[0003] For example, Chinese patent application number 201811112040.X discloses "A High-Efficiency and Precise Calibration Method for the Optical Path of a Laser Interferometer Based on PSD". While this method utilizes a PSD two-dimensional photosensitive position sensor as its core technology to achieve automated calibration of the laser interferometer's optical path by capturing beam offset data, the patent document lacks sufficient description of the specific measurement device structure used to implement this technology. Furthermore, it does not provide detailed explanations on how to use the acquired beam offset data to drive the automatic adjustment process and the underlying algorithm logic. This results in a need to improve the overall integration level of the measurement system, which may affect its widespread application and ease of operation in practical industrial or scientific research environments.

[0004] For example, Chinese patent application number 201710667421.3 discloses "a method for measuring automatic beam alignment of a laser interferometer." While this method achieves automatic beam alignment of the laser interferometer between the xy and yz planes, it employs a relatively complex algorithm in calculating beam offset, which increases the computational burden and complexity of the system to some extent. To achieve comprehensive in-plane automatic beam alignment, the overall structural design of the device also becomes complex, affecting manufacturing costs, ease of maintenance, and applicability in single-axis positioning error measurement applications. Summary of the Invention

[0005] To address the shortcomings or deficiencies of the existing technologies, this application aims to provide a rapid optical calibration device and method for machine tool precision based on a laser interferometer. This method utilizes a PSD two-dimensional photosensitive position sensor to acquire reflected light position deviation information at different measurement points. The host computer calculates this deviation information to obtain the pose adjustment parameters of the six-degree-of-freedom motion platform. Combined with the interferometer's light intensity information, a set of ideal parameters is determined, thereby ensuring that the interferometer maintains continuous illumination throughout the entire measurement process.

[0006] To solve the above-mentioned technical problems, this application provides the following technical solution: This application proposes a rapid optical calibration device for machine tools based on a laser interferometer, comprising: The interference beam splitting unit includes: a laser interferometer and a beam splitter assembly; The beam splitter kit includes a beam splitter, which is disposed inside the beam splitter kit. The beam splitter is used to split the reflected light into two paths. The transmitted light returns to the laser interferometer for interference ranging, and the refracted light enters the control motion unit for feedback control. The control motion unit includes: a two-dimensional photosensitive position sensor kit, a six-degree-of-freedom motion platform, and a microcontroller. The six-degree-of-freedom motion platform is rigidly connected to the laser interferometer and is used to adjust its posture. The two-dimensional photosensitive position sensor kit has a built-in signal processing circuit that can analyze the deviation of the refracted light in the interference beam splitting unit and transmit it to the microcontroller through a signal line. The microcontroller obtains a control signal through a built-in algorithm, and then controls the posture adjustment of the six-degree-of-freedom motion platform to achieve automatic light alignment.

[0007] Optionally, it also includes a host computer for receiving beam offset data detected by the two-dimensional photosensitive position sensor kit, calculating the six-degree-of-freedom pose adjustment parameters, and driving the six-degree-of-freedom motion platform to calibrate the optical path in real time through closed-loop control.

[0008] Optionally, the beam splitter is tilted and fixed within the beam splitter assembly. The transmitted light returns to the laser interferometer via the glass slide for distance measurement, and the refracted light enters the two-dimensional photosensitive position sensor assembly after passing through the filter and the light-transmitting aperture. Coaxial mounting ensures that the origin of the two-dimensional photosensitive position sensor spot coincides with the origin of the reflected light position.

[0009] Further optionally, the motion control of the six-degree-of-freedom motion platform includes: The global coordinate command is solved into the independent extension and retraction of six electric cylinders based on the inverse kinematics algorithm; The servo motor drives the electric cylinder to move in coordination, and the pitch, yaw and roll angles are adjusted by differential telescopic extension and contraction, while the three-dimensional translation is completed by synchronous and equal telescopic extension and contraction. By using a grating ruler and tilt sensor to provide real-time feedback of position and angle data, and combining PID and feedforward dynamic compensation algorithms, micron-level positioning accuracy and milliradian-level attitude accuracy are achieved.

[0010] More preferably, the solution algorithm of the host computer includes: Based on the deviation signal from the two-dimensional photosensitive position sensor and the interference light intensity data from the laser interferometer, an optomechanical coupling optimization model is constructed. Outlier data is removed using the 3σ criterion, and the ideal values ​​of the six-degree-of-freedom parameters are calculated by weighted geometric mean. The weighting coefficients are dynamically determined by the light intensity signal-to-noise ratio.

[0011] More preferably, the optical path design of the beam splitter kit satisfies: The light-transmitting aperture acts as an aperture stop, limiting the diameter of the refracted light spot to reduce edge scattering; The glass slide compensates for the optical path difference between the transmitted and refracted light paths, while protecting the surface of the beam splitter. The filter filters out stray light of non-laser wavelengths, improving the signal-to-noise ratio of the two-dimensional photosensitive position sensor to a preset threshold.

[0012] More preferably, the signal processing flow of the two-dimensional photosensitive position sensor kit includes: After converting the optical signal into an electrical signal, the position digital signal is output through the built-in board; The microcontroller parses digital signals and converts them into control commands for a six-degree-of-freedom platform, which are then transmitted to the motion controller via Ethernet.

[0013] Further optionally, the laser interferometer includes a dual-frequency laser reflector, and more preferably, it includes a dual-frequency helium-neon laser reflector, which is based on the heterodyne interference principle and the Doppler frequency shift effect. The dual-frequency laser interferometer calculates the relative displacement distance by: a dual-frequency laser generation and beam splitting step, a Doppler frequency shift and backlight interference step, a signal demodulation and phase detection step, a displacement calculation step, and a dual-frequency anti-interference step.

[0014] Furthermore, it also includes: Valid data is selected by real-time monitoring of the interferometer's light intensity signal strength and phase continuity characteristics; When the light intensity fluctuation meets the preset range and the phase changes, the corresponding pose parameters are recorded; By combining dynamic trajectory sampling and statistical optimization, the optimal operating point for maintaining the stability of the interferometric field is determined.

[0015] More preferably, the coaxial mounting of the beam splitter and the two-dimensional photosensitive position sensor kit is achieved by fine-tuning screws to ensure that the center of the beam splitter is coaxial with the origin of the two-dimensional photosensitive position sensor kit, with a deviation of no more than ±10μm.

[0016] More preferably, the pose adjustment target of the six-degree-of-freedom motion platform is: The intensity of the reflected light received by the laser interferometer should reach more than 80% of the initial value. Through continuous iterative adjustments, the phase of the interference signal becomes continuous and the light intensity fluctuations converge to an acceptable range.

[0017] Further optionally, the above-described dual-frequency laser generation and splitting steps include: the laser source emitting two linearly polarized beams with similar frequencies ( and The frequency difference is usually 100%. (e.g., 1~20 MHz). Polarizing beam splitter: separates two beams of light into a reference beam (...). ) and measuring light ( The projectiles were directed at the fixed reference mirror and the moving measuring mirror, respectively.

[0018] Further optionally, the above-described Doppler frequency shift and retroreflection interference steps include: measuring mirror motion: when the measuring mirror moves at a speed of... When the object moves, the frequency of the reflected measurement light shifts due to the Doppler effect:

[0019] in The speed of light; Interference signal generation: reference light ( ) and the reflected measurement light ( Heterodyne interference occurs within the interferometer, generating beat frequency signals: .

[0020] Further optionally, the above signal demodulation and phase detection steps include: photoelectric conversion: the beat frequency signal is converted into an electrical signal by a photodetector, and then amplified, filtered and entered into a phase comparator; Phase change count: Measuring mirror movement distance At that time, the amount of phase change satisfy:

[0021] in The wavelength of the laser in a vacuum (such as He-Ne laser) ); each phase period ( Corresponding displacement change .

[0022] Further optionally, the displacement calculation steps described above include: counter accumulation: recording the number of phase periods using an electronic counter. The displacement is calculated as follows:

[0023] In the formula: Air refractive index (needs to be compensated for in real time by ambient temperature, humidity, and air pressure; the formula is Euler's equation):

[0024] : air pressure (Pa) Temperature (°C) :humidity(%).

[0025] Further optionally, the above dual-frequency anti-interference steps include: common-mode noise suppression: the dual-frequency beat signal is not sensitive to common-mode interference such as temperature drift and mechanical vibration, and only responds to the frequency shift caused by the movement of the measuring mirror.

[0026] Further optionally, it also includes: a dynamic compensation step, which corrects the refractive index by measuring environmental parameters in real time. Ensure wavelength The accuracy.

[0027] Further optionally, the beam splitter kit further includes: a filter, a glass plate, and a light-transmitting aperture, wherein the filter is used to filter stray light of non-laser wavelengths; the glass plate is used to protect the surface of the beam splitter from contamination and to compensate for the optical path difference of the transmission / refraction path; and the light-transmitting aperture is used to limit the spot size and position the reference.

[0028] This application also proposes a calibration method for a rapid machine tool accuracy calibration device based on a laser interferometer, including: Install the beam splitter and the two-dimensional photosensitive position sensor kit coaxially, and adjust them so that the center of the beam splitter is coaxial with the origin of the two-dimensional photosensitive position sensor. Install the pyramidal reflector on the machine tool spindle and control the machine tool spindle 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. The laser interferometer emits a measurement laser, which is reflected back by a cornerstone mirror, producing reflected light. The reflected light is split into two paths by the beam splitter fixed in the beam splitter assembly; one path is transmitted light, which returns to the laser interferometer through the glass slide for interference ranging; the other path is refracted light, which enters the two-dimensional photosensitive position sensor in the interference beam splitter unit through the light-transmitting aperture. The two-dimensional photosensitive position sensor detects the two-dimensional deviation of refracted light on the measurement plane, converts the optical signal into an electrical signal, outputs the position digital signal through the built-in board, and transmits it to the microcontroller through the signal line; The microcontroller analyzes the position digital signal and outputs control signals based on the geometric relationship between the device and the machine tool; The six-degree-of-freedom motion platform receives control signals and adjusts the device's posture by modifying the pitch angle and lateral position. The moving corner cone reflector and the six-degree-of-freedom motion platform obtain a series of pose parameters, and combine them with the light intensity information from the interferometer to determine a set of ideal parameters.

[0029] Compared with the prior art, this application has the following technical effects: This application solves the problem of difficulty in obtaining the position deviation information of reflected light in laser interferometers by employing a PSD two-dimensional photosensitive position sensor; it also solves the problem of the PSD spot origin not coinciding with the position origin of reflected light by adopting a structure in which the PSD and the beam splitter are coaxially connected in series; and by using a host computer to calculate the beam position offset information and transmitting the data to a motion controller to control the movement of a six-degree-of-freedom platform, this application realizes real-time adjustment of the measurement posture of the laser interferometer during the measurement process, solving the problems of long manual light alignment time and complex operation of laser interferometers, and realizing automated light alignment measurement of laser interferometers. Attached Figure Description

[0030] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This application provides a schematic diagram of a rapid machine tool precision calibration device based on a laser interferometer, according to one embodiment. Figure 1 ; Figure 2 This application provides a schematic diagram of a rapid machine tool precision calibration device based on a laser interferometer, according to one embodiment. Figure 2 ; Figure label: 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-Transmitting hole component. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] like Figure 1 and Figure 2 As shown, in one embodiment of this application, a machine tool precision rapid optical calibration device based on a laser interferometer 1 includes: The interference beam splitting unit includes: a laser interferometer 1 and a beam splitter assembly 4; the laser interferometer 1 can emit a helium-neon laser with a wavelength of 633nm, which passes through a corner cone reflector fixed in the machine tool workspace, and the laser interferometer 1 can receive the reflected light and calculate the relative displacement distance; The beam splitter assembly 4 includes a beam splitter 5, which is disposed inside the beam splitter assembly 4. The beam splitter 5 is used to split the reflected light into two paths: the transmitted light returns to the laser interferometer 1 for interferometric ranging, and the refracted light enters the control motion unit for feedback control. The beam splitter 5 splits the reflected laser into transmitted light (returning to the interferometer for ranging) and refracted light (guided to the PSD to detect position deviation) according to a certain ratio. The motion control unit includes: a two-dimensional photosensitive position sensor kit (PSD) 3, a six-degree-of-freedom motion platform 2, and a microcontroller; 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 microcontroller through a signal line. The microcontroller obtains the control signal through a built-in algorithm, and then controls the pose adjustment of the six-degree-of-freedom motion platform 2 through a network cable to achieve automatic light alignment.

[0033] This embodiment of the application solves the problem of difficulty in obtaining the position deviation information of the reflected light of the laser interferometer 1 by adopting the PSD two-dimensional photosensitive position sensor kit 3; this application solves the problem of the PSD spot origin not coinciding with the position origin of the reflected light by adopting the structure of PSD and beam splitter 5 coaxially connected in series.

[0034] Further optionally, in this embodiment, the beam splitter assembly 4 further includes: a filter 6, a glass slide 7, and a light-transmitting aperture 8, wherein the filter 6 is used to filter stray light of non-laser wavelengths and improve the signal-to-noise ratio of the PSD signal; the glass slide 7 is used to protect the surface of the beam splitter 5 from contamination and to compensate for the optical path difference of the transmission / refractive light path; and the light-transmitting aperture 8 is used to limit the spot size and position the reference to ensure the accurate position of the PSD detection spot.

[0035] In this embodiment, 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 clamp. The beam splitter assembly 4 is installed in front of the laser emission port of the laser interferometer 1 and is fixed to the housing of the laser interferometer 1 by threads or snaps, ensuring that the optical axis is coaxial with the laser emission direction. The beam splitter 5 is fixed inside the assembly at a 45° angle, splitting the reflected light into transmitted light returning to the interferometer and refracted light entering the two-dimensional photosensitive position sensor assembly 3. The filter 6 is located downstream of the refracted light path of the beam splitter 5, filtering stray light. The light-transmitting aperture 8 is close to the filter 6 and serves as an aperture stop, limiting the diameter of the refracted light spot and reducing edge scattering. The glass plate 7 is located in the transmitted light path of the beam splitter 5, protecting the beam splitter surface and assisting the transmitted light to return to the interferometer. The two-dimensional photosensitive position sensor assembly 3 is located at the end of the refracted light path of the beam splitter assembly 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 the signal to the six-degree-of-freedom motion platform 2.

[0036] Further optionally, the laser interferometer 1 includes a dual-frequency laser reflector. Based on the heterodyne interference principle and the Doppler frequency shift effect, the dual-frequency laser interferometer 1 calculates the relative displacement distance, including: dual-frequency laser generation and beam splitting steps, Doppler frequency shift and backlight interference steps, signal demodulation and phase detection steps, displacement calculation steps, and dual-frequency anti-interference steps.

[0037] Step one, in the above-mentioned dual-frequency laser generation and beam splitting steps, includes: the laser source emitting two linearly polarized beams with similar frequencies ( and The frequency difference is usually 100%. (e.g., 1~20 MHz). Polarizing beam splitter 5: Separates two beams of light into a reference beam ( ) and measuring light ( The projectiles were directed at the fixed reference mirror and the moving measuring mirror, respectively.

[0038] Step two, in the above-mentioned Doppler frequency shift and retroreflection interference steps, includes: measuring mirror motion: when the measuring mirror moves at a speed of... When the object moves, the frequency of the reflected measurement light shifts due to the Doppler effect:

[0039] in The speed of light; Interference signal generation: reference light ( ) and the reflected measurement light ( Heterodyne interference occurs within the interferometer, generating beat frequency signals: .

[0040] Step 3, in the above signal demodulation and phase detection steps, includes: photoelectric conversion: the beat frequency signal is converted into an electrical signal by a photodetector, and after amplification and filtering, it enters the phase comparator; Phase change count: Measuring mirror movement distance At that time, the amount of phase change satisfy:

[0041] in The wavelength of the laser in a vacuum (such as He-Ne laser) ); each phase period ( Corresponding displacement change .

[0042] Step four, in the above displacement calculation steps, includes: counter accumulation: recording the number of phase periods using an electronic counter. The displacement is calculated as follows:

[0043] In the formula: Air refractive index (needs to be compensated for in real time by ambient temperature, humidity, and air pressure; the formula is Euler's equation):

[0044] : air pressure (Pa) Temperature (°C) :humidity(%).

[0045] Step 5, in the above dual-frequency anti-interference steps, includes: common-mode noise suppression: the dual-frequency beat signal is not sensitive to common-mode interference such as temperature drift and mechanical vibration, and only responds to the frequency shift caused by the movement of the measuring mirror.

[0046] Optionally, this embodiment further includes a dynamic compensation step, which corrects the refractive index by measuring environmental parameters in real time. Ensure wavelength The accuracy.

[0047] In another embodiment of this application, a calibration method for a machine tool precision rapid calibration device based on a laser interferometer 1 is also proposed, including (a workflow in which software and hardware work together): Step 1: Install the beam splitter 5 and the two-dimensional photosensitive position sensor kit 3 coaxially, and adjust them so that the center of the beam splitter 5 is coaxial with the origin of the two-dimensional photosensitive position sensor kit 3; Step 2: Install the pyramidal 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 1 can receive the reflected light at the initial moment. Step 3: The laser interferometer 1 emits a measurement laser, which is reflected back by the cornerstone mirror to produce reflected light; Step 4: The reflected light passes through the beam splitter 5 fixed in the beam splitter kit 4 and is split into two paths; one path is transmitted light, which passes through the glass slide 7 and returns to the laser interferometer 1 for interference ranging; the other path is refracted light, which passes through the light-transmitting aperture 8 and enters the two-dimensional photosensitive position sensor 3 in the interference beam splitting unit. Step 5: The two-dimensional photosensitive position sensor kit 3 detects the two-dimensional deviation of the refracted light on the measurement plane, converts the optical signal into an electrical signal, outputs the position digital signal through the built-in board, and transmits it to the microcontroller through the signal line; Step 6: The microcontroller analyzes the position digital signal and outputs control signals based on the geometric relationship between the device and the machine tool; Step 7: The six-degree-of-freedom motion platform receives the control signal and adjusts the device's pose by modifying the pitch angle and lateral position, so that the reflected light quality received by the laser interferometer 1 reaches 80%. The host computer sends the target pose parameters (including three-dimensional translation and rotation angles) via Ethernet. The platform controller uses inverse kinematics algorithm to solve the global coordinate command into the independent extension and retraction of the six electric cylinders. Subsequently, the servo motor drives the electric cylinders to move in coordination—adjusting the pitch / yaw / roll angles through asymmetric extension and retraction (such as generating torque through the differential extension and retraction of the diagonal electric cylinder 1), and synchronously extending and retracting in equal amounts to complete the X / Y / Z translation (supplemented by Z-axis compensation to maintain the platform's flatness). During the movement, the grating ruler and tilt sensor provide real-time feedback of position and angle data. Closed-loop control combined with dynamic compensation algorithm (PID + feedforward) corrects errors, ultimately achieving micron-level positioning and milliradian-level attitude accuracy, meeting the requirements of high-precision optical alignment or precision manufacturing, so that the reflected light quality received by the laser interferometer reaches 80%. Step 8: Move the corner bevel mirror. The six-degree-of-freedom motion platform obtains a series of pose parameters and, combined with the interferometer's light intensity information, determines a set of ideal parameters. These ideal parameters can be represented by the average of the six parameters ensuring continuous light transmission from the interferometer, thus guaranteeing continuous light transmission throughout the measurement process. The determination of these ideal parameters can be described as a dynamic trajectory sampling and statistical optimization process based on the constraint of interferometric signal continuity. During the motion calibration process of the corner bevel mirror driven by the six-degree-of-freedom platform, by real-time monitoring of the interferometer's light intensity signal intensity I(t) and phase continuity characteristics, an effective data screening criterion is constructed: an effective data screening criterion is established if and only if the light intensity fluctuation satisfies |ΔI(t) / I... avg When |≤1% and phase jump Δφ(t)<π / 2 (excluding the unlocked state), the platform pose parameters P at the corresponding time are recorded synchronously. i =[x i ,y i ,z i ,θ xi ,θ yi ,θ zi Then, robust processing is performed on the N sets of parameters that meet the conditions: 1) Use the 3σ criterion to remove outliers from the motion trajectory; 2) Calculate the weighted geometric mean of the six-degree-of-freedom parameters:

[0048] Among them, the weighting coefficient wk is determined by the light intensity signal-to-noise ratio (SNR) at the corresponding time. k Dynamically determined, i.e., 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 interferometric field through optical-mechanical coupling characteristic correlation. Compared with simple arithmetic averaging, it can reduce the impact of mechanical nonlinear error on parameter estimation. Thus, it ensures that the interferometer remains continuously lit throughout the entire measurement process.

[0049] This application solves the problem of difficulty in obtaining the position deviation information of the reflected light in the laser interferometer 1 by employing a PSD two-dimensional photosensitive position sensor kit 3; it also solves the problem of the PSD spot origin not coinciding with the position origin of the reflected light by adopting a coaxial series structure of the PSD and the beam splitter 5; furthermore, by using a host computer to calculate the beam position offset information and transmitting the data to a motion controller to control the movement of the six-degree-of-freedom platform, this application enables the laser interferometer 1 to adjust its measurement posture in real time during the measurement process, solving the problems of long manual alignment time and complex operation of the laser interferometer 1, and realizing automated alignment measurement of the laser interferometer 1. In summary, this application has good market application prospects.

[0050] In the description of this application, unless otherwise expressly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0051] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0052] In the description of this embodiment, the terms "upper," "lower," "left," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0053] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. The preferred embodiments have been described in detail. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A rapid optical calibration device for machine tools based on a laser interferometer, characterized in that, include: The interference beam splitting unit includes: a laser interferometer and a beam splitter assembly; The beam splitter kit includes a beam splitter, which is disposed inside the beam splitter kit. The beam splitter is used to split the reflected light into two paths. The transmitted light returns to the laser interferometer for interference ranging, and the refracted light enters the control motion unit for feedback control. The motion control unit includes: a two-dimensional photosensitive position sensor kit, a six-degree-of-freedom motion platform, and a microcontroller; the two-dimensional photosensitive position sensor kit 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 microcontroller through a signal line. The microcontroller obtains the control signal through a built-in algorithm, and then controls the pose adjustment of the six-degree-of-freedom motion platform to achieve automatic light alignment.

2. The machine tool precision rapid optical calibration device based on a laser interferometer according to claim 1, characterized in that, The laser interferometer includes a dual-frequency laser reflector. Based on the principle of heterodyne interference and the Doppler frequency shift effect, the dual-frequency laser interferometer calculates the relative displacement distance, including: dual-frequency laser generation and beam splitting steps, Doppler frequency shift and backlight interference steps, signal demodulation and phase detection steps, displacement calculation steps, and dual-frequency anti-interference steps.

3. The machine tool precision rapid optical calibration device based on a laser interferometer according to claim 2, characterized in that, The above-mentioned dual-frequency laser generation and splitting steps include: the laser source emitting two linearly polarized beams with similar frequencies ( and The frequency difference is usually 100%. (e.g., 1~20 MHz). Polarizing beam splitter: separates two beams of light into a reference beam (...). ) and measuring light ( The projectiles were directed at the fixed reference mirror and the moving measuring mirror, respectively.

4. The machine tool precision rapid optical calibration device based on a laser interferometer according to claim 2, characterized in that, The above-described Doppler frequency shift and retroreflection interference steps include: measuring mirror motion: when the measuring mirror moves at a speed of... When the object moves, the frequency of the reflected measurement light shifts due to the Doppler effect: in The speed of light; Interference signal generation: reference light ( ) and the reflected measurement light ( Heterodyne interference occurs within the interferometer, generating beat frequency signals: 。 5. The machine tool precision rapid optical calibration device based on a laser interferometer according to claim 2, characterized in that, The above signal demodulation and phase detection steps include: photoelectric conversion: the beat frequency signal is converted into an electrical signal by a photodetector, and then amplified, filtered and entered into a phase comparator; Phase change count: Measuring mirror movement distance At that time, the amount of phase change satisfy: in The wavelength of the laser in a vacuum (such as He-Ne laser) ); each phase period ( Corresponding displacement change .

6. The machine tool precision rapid optical calibration device based on a laser interferometer according to claim 2, characterized in that, The displacement calculation steps described above include: counter accumulation: recording the number of phase periods using an electronic counter. The displacement is calculated as follows: In the formula: Air refractive index (needs to be compensated for in real time by ambient temperature, humidity, and air pressure; the formula is Euler's equation): : air pressure (Pa) Temperature (°C) :humidity(%).

7. The machine tool precision rapid optical calibration device based on a laser interferometer according to claim 2, characterized in that, The above dual-frequency anti-interference steps include: common-mode noise suppression: the dual-frequency beat signal is not sensitive to common-mode interference such as temperature drift and mechanical vibration, and only responds to the frequency shift caused by the movement of the measuring mirror.

8. The machine tool precision rapid optical calibration device based on a laser interferometer according to any one of claims 2 to 7, characterized in that, Also includes: The dynamic compensation step corrects the refractive index by measuring environmental parameters in real time. Ensure wavelength The accuracy.

9. The machine tool precision rapid optical calibration device based on a laser interferometer according to claim 1, characterized in that, The beam splitter kit also includes: a filter, a glass plate, and a light-transmitting aperture, wherein the filter is used to filter stray light of non-laser wavelengths; the glass plate is used to protect the surface of the beam splitter from contamination and to compensate for the optical path difference of the transmission / refractive light path; and the light-transmitting aperture is used to limit the spot size and position the reference.

10. The calibration method of the machine tool precision rapid calibration device based on a laser interferometer as described in any one of claims 1 to 9, characterized in that, include: Install the beam splitter and the two-dimensional photosensitive position sensor kit coaxially, and adjust them so that the center of the beam splitter is coaxial with the origin of the two-dimensional photosensitive position sensor. Install the pyramidal reflector on the machine tool spindle and control the machine tool spindle 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. The laser interferometer emits a measurement laser, which is reflected back by a corner bevel mirror to produce reflected light. The reflected light is split into two paths by the beam splitter fixed in the beam splitter assembly; one path is transmitted light, which returns to the laser interferometer through the glass slide for interference ranging; the other path is refracted light, which enters the two-dimensional photosensitive position sensor in the interference beam splitter unit through the light-transmitting aperture. The two-dimensional photosensitive position sensor detects the two-dimensional deviation of refracted light on the measurement plane, converts the optical signal into an electrical signal, outputs the position digital signal through the built-in board, and transmits it to the microcontroller through the signal line; The microcontroller analyzes the position digital signal and outputs control signals based on the geometric relationship between the device and the machine tool; The six-degree-of-freedom motion platform receives control signals and adjusts the device's posture by modifying the pitch angle and lateral position. The moving corner cone mirror and the six-degree-of-freedom motion platform obtain a series of pose parameters, and combine them with the light intensity information from the interferometer to determine a set of ideal parameters.

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