A device and method for detecting the angle precision of a two-dimensional scanning mechanism with a large range and high precision

Abstract

This invention discloses a device and method for detecting the high-precision angle measurement accuracy of a two-dimensional scanning mechanism over a wide range. The detection device includes a two-dimensional scanning mechanism, a multi-tooth indexing stage, a photoelectric autocollimator, a marble platform, an angle acquisition circuit, a motion control box, a screw plate, horizontal adjustment shims, a photoelectric autocollimator mounting fixture, an angle acquisition computer, and a ground inspection unit. The multi-tooth indexing stage is placed on the marble platform. The photoelectric autocollimator is mounted on the multi-tooth indexing stage using the photoelectric autocollimator mounting fixture. Horizontal adjustment shims are used to adjust the multi-tooth indexing stage and the two-dimensional scanning mechanism to ensure parallelism, guaranteeing that the photoelectric autocollimator can receive the specular reflection value of the two-dimensional pointing mechanism. The detection method includes static calibration and dynamic calibration, with static calibration further including large-cycle angle accuracy calibration and small-cycle angle accuracy calibration measurements. This invention provides a third-party angle measurement device and method capable of achieving accuracy within 1 arcsecond, centered around the device under test.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wide-range high-precision angle measurement detection devices and calibration techniques, and in particular to a wide-range high-precision angle measurement precision detection device and method for a two-dimensional scanning mechanism. BACKGROUND

[0002] With the control refinement of the motion control of the two-dimensional scanning mechanism, the angle measurement precision requirement index is also increasingly high. Since the two-dimensional scanning mechanism has a relatively large volume and weight, a third-party angle measurement device and method that can achieve an angle of 1 second or less around the measured equipment is increasingly important.

[0003] Current angle measurement devices mainly include theodolites, gyroscopes, polyhedral prisms, gyroscopes, and CCD arrays. High-resolution CCD arrays are limited to scanning mechanisms that must have high-precision mirrors. Different high-precision mirrors need to be selected according to different inertias. Theodolites are limited by their own precision reading range fluctuations, which do not meet the precision requirements. Polyhedral prisms are only suitable for static calibration. Gyroscopes have a certain amount of measurement deviation during long-term testing and need to be aligned regularly to prevent test data deviation.

[0004] The above-mentioned existing angle measurement devices cannot simultaneously meet the requirements of ultra-high precision, dynamic uniform speed precision at a certain frequency, and stability during long-term measurement, and it is difficult to achieve measurement operations that can achieve an angle of 1 second or less around the measured equipment. SUMMARY

[0005] The present application aims to provide a wide-range high-precision angle measurement precision detection device and method for a two-dimensional scanning mechanism to solve the angle measurement precision device of the two-dimensional scanning mechanism. The present application provides a third-party angle measurement device and method that can achieve an angle of 1 second or less around the measured equipment.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A wide-range high-precision angle measurement precision detection device for a two-dimensional scanning mechanism, comprising a two-dimensional scanning mechanism, a multi-tooth indexing table, an optical autocollimator, a marble platform with a flatness of 0 or above, an angle acquisition circuit, a motion control box, a screw plate, a horizontal adjustment pad, an optical autocollimator installation tool, an angle acquisition computer, and a ground detector.

[0008] The two-dimensional scanning mechanism and the multi-tooth indexing stage are placed on a marble platform. The photoelectric autocollimator mounting fixture is installed on the multi-tooth indexing stage, and the photoelectric autocollimator is mounted on the photoelectric autocollimator mounting fixture. Horizontal adjustment shims are used to adjust the multi-tooth indexing stage and the two-dimensional scanning mechanism to be parallel. This ensures that the photoelectric autocollimator can receive the specular reflection value of the two-dimensional pointing mechanism. The angle acquisition circuit is connected to the motion control box. The motion control box is connected to the ground sensor, the photoelectric autocollimator is connected to the angle acquisition computer, and the ground sensor is connected to the angle acquisition computer via cables.

[0009] The flatness of the multi-tooth indexing table is 0.01 mm, the absolute accuracy of 360 degrees is 0.5″, and the accuracy within the measured range of 40 degrees is 0.2″.

[0010] The photoelectric autocollimator has an absolute angle measurement accuracy of 0.1″, a repeatability better than 0.04″, a resolution of 0.001″, a field of view of 3000″*3000″, a dynamic angle measurement data acquisition speed of 60Hz, and a high-speed acquisition speed of 1kHz.

[0011] The angle acquisition circuit is used to collect the position change of the inductive synchronizer. The angle conversion frequency is 64kHz, the resolution is 0.05″, and the stability is better than 0.1″.

[0012] The motion control box is used to acquire the position information of the angle acquisition circuit and control the motor of the two-dimensional scanning mechanism, with a scanning control accuracy better than 0.2″.

[0013] The angle acquisition computer is used to connect to the angle change value of the photoelectric autocollimator, and the angle change is stored in the angle acquisition computer.

[0014] The ground sensor is used to send commands to the motion control box, causing the two-dimensional scanning mechanism to point for scanning; the ground sensor is also used to collect position information of the angle acquisition circuit and current and motion mode data of the motion control box, and its acquisition frequency supports up to 10MHz.

[0015] Furthermore, the thickness of the leveling shim is between 0.001 mm and 0.05 mm.

[0016] A method for detecting the large-scale, high-precision angle measurement accuracy of a two-dimensional scanning mechanism, using the aforementioned two-dimensional scanning mechanism large-scale, high-precision angle measurement accuracy detection device, specifically includes the following steps:

[0017] Step 1: Use the horizontal adjustment shims to adjust the perpendicularity of the photoelectric autocollimator to the mirror of the two-dimensional scanning mechanism, determine the angle measurement range, and repeat the pointing until the pitch error value of the angle measurement range is adjusted to less than or equal to 1″.

[0018] Step 2: Perform static calibration, including the following steps:

[0019] Step 2.1: Perform large-cycle angle accuracy calibration: Perform angle calibration to determine the angle measurement range at 5′ intervals;

[0020] Step 2.2: Perform small-cycle angle accuracy calibration measurement: Select up to 6 1-degree intervals of the inductive synchronizer, and calibrate the angle of each 1-degree interval in turn; with an interval of 2.5″, a total of 24 measurement points are used to complete the 1-degree range angle calibration of the inductive synchronizer;

[0021] Step 3: Perform dynamic accuracy calibration, including the following steps:

[0022] Step 3.1: The ground inspection calculates the distance of the two-dimensional scanning mechanism when it enters the uniform speed segment during movement, and calculates the distance to reach the field of view of the photoelectric autocollimator. When it reaches the field of view of the photoelectric autocollimator, the ground inspection sends a synchronization flag to the acquisition angle computer to synchronize the initial measurement time of the photoelectric autocollimator and the ground inspection, and align the field of view coverage.

[0023] Step 3.2: The ground inspection sends a low-speed uniform scanning command to the control box of the two-dimensional scanning mechanism, and the two-dimensional scanning mechanism begins to point and scan;

[0024] Step 3.3: After the two-dimensional scanning mechanism reaches a constant speed, when it reaches the field of view of the photoelectric autocollimator, the ground detection feedback flag is sent to the acquisition angle computer for acquisition.

[0025] Step 3.4: Record the measured position and time of entering the field of view of the photoelectric autocollimator, and at the same time record the position and time of the induction synchronizer;

[0026] Step 3.5: Control the two-dimensional scanning mechanism to complete the acquisition of the full field of view position of the photoelectric autocollimator. Repeat steps 3.2 to 3.4 to complete the acquisition of three sets of autocollimator data at the same angle and confirm the repeatability of the test data.

[0027] Step 3.6: Rotate the multi-tooth indexing table 1000″ and repeat steps 3.1 to 3.5.

[0028] Furthermore, in step 1, the angle measurement range is ±20 degrees, that is, the pointing range of the two-dimensional scanning mechanism is ±1200′; the specific method for adjusting the pitch error within the ±20 degree angle measurement range is as follows:

[0029] The ground inspection unit sends a command to point to -20 degrees, uses a multi-tooth indexing table to move to -20 degrees and records the current pitch value, then points to 20 degrees and records the current pitch value again. The pitch value error within the ±20 degree range is compared, and the horizontal adjustment shims are used for adjustment. The process is repeated until the pitch error within the ±20 degree range is adjusted to less than 1″.

[0030] Furthermore, in step 2.1, the angle measurement range is ±20 degrees. The specific method for calibrating the accuracy of the large-cycle angle within a 40° range using the inductive synchronizer is as follows:

[0031] Step 2.1.1: Point the two-dimensional scanning mechanism to -20 degrees, move the multi-tooth indexing stage to +20 degrees, adjust the pitch error of the light spot field of view center to within ±1 arcsecond, and determine this as the starting point. The current starting point photoelectric autocollimator is recalibrated to 0°0′0″. Record the current data values ​​of the current inductive synchronizer and the photoelectric autocollimator;

[0032] Step 2.1.2: Then, rotate the two-dimensional scanning mechanism at 5' intervals while simultaneously rotating the multi-scale indexing table in the opposite direction. Both the two-dimensional scanning mechanism and the multi-scale indexing table rotate 5' each time, and the results are tested and recorded sequentially. A total of 480 sets of data values ​​were collected from the inductive synchro and photoelectric autocollimator; tests were conducted every 5 minutes. The difference between two test data points of the photoelectric autocollimator;

[0033] The value is calculated as follows:

[0034] After the multi-tooth indexing table completes its rotation and locks, wait 5 seconds for it to stabilize, then start collecting data from the photoelectric autocollimator for 1 second and perform averaging to obtain photoelectric autocollimator data A.

[0035]

[0036] N represents the number of data acquisitions, and ai represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value.

[0037] After the multi-tooth indexing table completes its rotation and locks, waits 5 seconds for stabilization, and then begins acquiring data from the photoelectric autocollimator for 1 second. This data is then averaged to obtain photoelectric autocollimator data B, followed by 5 seconds of stationary data acquisition.

[0038]

[0039] N represents the number of data acquisitions, and bi represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value.

[0040] The difference between photoelectric autocollimator data A and photoelectric autocollimator data B is denoted as

[0041]

[0042] Step 2.1.3: Measure steps 2.1.1 to 2.1.2 a total of 3 times according to repeatability requirements.

[0043] Furthermore, in step 2.2, the specific method for calibrating the angle within a 1-degree range of the inductive synchronizer is as follows:

[0044] Step 2.2.1: Point the two-dimensional scanning mechanism at n degrees, where n is greater than or equal to 0. Move the multi-tooth indexing stage to n degrees, align it with the optical axis, and acquire the current data of the photoelectric autocollimator. Adjust the center of the light spot field of view to within ±1 arcsecond to determine the starting point. Recalibrate the photoelectric autocollimator at the current starting point to 0°0′0. Record the current data values ​​of the current induction synchronizer and the photoelectric autocollimator.

[0045] Step 2.2.2: Rotate the 2D scanning mechanism at 2.5″ intervals while simultaneously rotating the multi-scale indexing table in the opposite direction. Both the 2D scanning mechanism and the multi-scale indexing table rotate 2.5″ each time. Test and record the results sequentially at 2.5″ intervals. A total of 24 sets of data were collected from the inductive synchro and photoelectric autocollimator; tests were conducted every 2.5 seconds. This represents the difference between two data points from the photoelectric autocollimator during two separate tests.

[0046] The value is calculated as follows:

[0047] After the multi-tooth indexing table completes its rotation and locks, wait 5 seconds for it to stabilize, then start collecting data from the photoelectric autocollimator for 1 second and perform averaging to obtain photoelectric autocollimator data A.

[0048]

[0049] N represents the number of data acquisitions, and ai represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value.

[0050] After the multi-tooth indexing table completes its rotation and locks, waits 5 seconds for stabilization, and then begins acquiring data from the photoelectric autocollimator for 1 second. This data is then averaged to obtain photoelectric autocollimator data B, followed by 5 seconds of stationary data acquisition.

[0051]

[0052] N represents the number of data acquisitions, and bi represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value.

[0053] The difference between photoelectric autocollimator data A and photoelectric autocollimator data B is denoted as

[0054]

[0055] Step 2.2.3: Perform the measurements from Step 2.2.1 to Step 2.2.2 a total of 3 times according to the repeatability requirements.

[0056] Furthermore, in the dynamic accuracy calibration process of step 3, the acceleration curve of the fixed two-dimensional scanning mechanism is set according to the algorithm. Different acceleration distances are required according to different speeds. In the current test acquisition, the two-dimensional scanning mechanism needs to perform a slow, uniform scan at an ultra-low speed. The scanning speed of the two-dimensional scanning mechanism is set to 0.003 degrees per second. The photoelectric autocollimator performs test acquisition of the current scanning process at a frequency of 60 Hz.

[0057] The scanning control system accelerates at a rate of 0.003 degrees per second, with a control frequency of 200 Hz. The acceleration time is calculated as 2 beats (100 Hz) to obtain the degree of movement.

[0058] L = 1 / 2VT

[0059] V represents the current scanning speed of the 2D scanning mechanism, in degrees per second; T represents the acceleration time of the 2D scanning mechanism, in seconds; L represents the degree of movement of the 2D scanning mechanism during the acceleration phase, i.e., the angular distance of movement of the 2D scanning mechanism during the acceleration phase, in degrees.

[0060] Then convert the degree of movement to arcseconds for easier unit standardization:

[0061] D = L * 3600

[0062] D represents the angular distance traveled by the acceleration segment of the two-dimensional scanning mechanism, in arcseconds.

[0063] The angular distance of the acceleration phase is confirmed to be D. A time of D plus 0.1 arcseconds is allowed for the start-up time of the photoelectric autocollimator's dynamic acquisition. After passing through an angle of D, when the ground detector reaches a constant speed, a feedback flag is sent to the acquisition angle computer to start acquisition. After another 0.1 seconds, the data enters the field of view of the photoelectric autocollimator and is collected and stored.

[0064] Compared with the prior art, the present invention provides a device and method for detecting the large-range high-precision angle measurement accuracy of a two-dimensional scanning mechanism, which has the following beneficial effects:

[0065] This patent relates to a method for calibrating a wide-range angle measurement of an optoelectronic autocollimator based on a multi-tooth indexing stage. The aim is to achieve effective calibration of the wide-range angle measurement accuracy of a large two-dimensional scanning mechanism through a high-precision reference device, thereby ensuring its reliable application in high-precision fields.

[0066] In this invention, the photoelectric autocollimator possesses excellent angle measurement performance, with an absolute angle measurement accuracy of 0.1″, a repeatability better than 0.04″, a resolution as high as 0.001″, and a field of view of only 3000″ (approximately 0.833°). To achieve accurate calibration of the autocollimator's wide-range angle measurement accuracy, a multi-tooth indexing stage is selected as the core calibration reference device in this invention.

[0067] This multi-tooth indexing stage features high precision: its flatness is 0.01 mm, providing a stable reference plane for the calibration process, effectively avoiding optical path offset errors caused by plane tilt, and ensuring the stability of the measurement optical path; its 360-degree absolute accuracy reaches 0.5″, supporting angle calibration extension across the entire circumference; most importantly, its accuracy reaches 0.2″ within a 40-degree measurement range, which completely covers the 3000″ field of view of the photoelectric autocollimator, and its accuracy level is reasonably matched with the absolute angle measurement accuracy (0.1″) of the autocollimator, providing a reliable standard angle reference for calibration. Using the above method, with the help of the multi-tooth indexing stage's high precision of 0.2″ within a 40-degree range, absolute precision of 0.5″ within a 360-degree range, and flatness of 0.01 mm, large-scale angle measurement calibration of large two-dimensional scanning mechanisms can be accurately completed. In terms of accuracy and uncertainty calculation, according to the principle of calculating three times the absolute measurement error, the measurement uncertainty corresponding to the absolute angle measurement accuracy of 0.1″ of the photoelectric autocollimator is 0.2″, and the measurement uncertainty corresponding to the multi-tooth indexing stage's 0.2″ within a 40-degree range is 0.4″. Finally, the total error of the comprehensive measurement result is controlled at 0.9″, so the final measurement accuracy can meet the calibration requirements within 1 arcsecond. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of the structure of the large-range high-precision angle measurement accuracy detection device of the two-dimensional scanning mechanism in this invention.

[0069] In the picture:

[0070] 1-Two-dimensional scanning mechanism, 2-Multi-tooth indexing stage, 3-Photoelectric autocollimator, 4-Marble platform, 5-Angle acquisition circuit, 6-Motion control box, 7-Screw plate, 8-Photoelectric autocollimator mounting fixture, 9-Angle acquisition computer.

[0071] Figure 2 This is a schematic diagram of the ground inspection in this invention.

[0072] The diagram illustrates the communication method between the motion control box and the ground inspection system, as well as the functions of the ground inspection system. Detailed Implementation

[0073] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0074] like Figure 1The diagram shows a schematic of a large-scale high-precision angle measurement accuracy detection device for a two-dimensional scanning mechanism. In this embodiment, the device includes a two-dimensional scanning mechanism 1, a multi-tooth indexing stage 2, a photoelectric autocollimator 3, a marble platform with a flatness of 0 or higher 4, an angle acquisition circuit 5, a motion control box 6, a screw plate 7, a horizontal adjustment shim, a photoelectric autocollimator mounting fixture 8, an angle acquisition computer 9, and a ground detector.

[0075] Angle acquisition circuit 5, motion control box 6, 2D scanning mechanism 1, and multi-tooth indexing stage 2 are placed on the surface of marble platform 4. Photoelectric autocollimator mounting fixture 8 is installed on multi-tooth indexing stage 2, and photoelectric autocollimator 3 is installed on photoelectric autocollimator mounting fixture 8. Horizontal adjustment shims are used to adjust multi-tooth indexing stage 2 and 2D scanning mechanism 1 to ensure parallelism. This ensures that photoelectric autocollimator 3 can receive the specular reflection value of 2D pointing mechanism 1. Angle acquisition circuit 7 is connected to motion control box 6. Cables connect motion control box 6 to ground sensor, photoelectric autocollimator 3 to angle acquisition computer 9, and ground sensor to angle acquisition computer 9. Ground sensor is placed away from marble platform 4.

[0076] Specifically, in this embodiment, the flatness of the multi-tooth indexing table 2 is 0.01 mm, the absolute accuracy of 360 degrees is 0.5″, and the accuracy within the measured range of 40 degrees is 0.2″.

[0077] Specifically, in this embodiment, the absolute angle measurement accuracy of the photoelectric autocollimator 3 is 0.1″, the repeatability is better than 0.04″, the resolution is 0.001″, the field of view is 3000″*3000″, the dynamic angle measurement data acquisition is 60Hz, and the high-speed acquisition is 1kHz.

[0078] Specifically, in this embodiment, the angle acquisition circuit 5 is used to collect the position change of the induction synchronizer, with an angle conversion frequency of 64kHz, a resolution of 0.05″, and a stability better than 0.1″.

[0079] Specifically, in this embodiment, the motion control box 6 is used to acquire the position information of the angle acquisition circuit and control the motor of the two-dimensional scanning mechanism 1, with a scanning control accuracy better than 0.2″.

[0080] The angle acquisition computer 9 is used to connect to the photoelectric autocollimator 3 to measure the angle change value, and the angle change is stored in the angle acquisition computer 9.

[0081] The ground detector (i.e., the host computer for sending and receiving instructions) is used to send instructions to the motion control box 6, causing the two-dimensional scanning mechanism 1 to point for scanning; the ground detector is also used to collect position information of the angle acquisition circuit and current and motion mode data of the motion control box; the ground detector's acquisition frequency is adjustable, and can support up to 10MHz, for example, an 8kHz acquisition frequency can be selected during measurement.

[0082] The ground testing equipment is based on a general-purpose ground testing platform. The equipment uses a standard PCIe service platform and incorporates various general-purpose I / O function modules to meet the requirements of various testing application environments. It is designed based on mature server equipment, and consists of custom-designed general-purpose testing modules (RS422 interface cards, digital I / O interface cards, and AD interface cards) and supporting custom embedded software. A unified power supply module is installed inside the chassis to provide power to all modules, using an AC power interface. The testing software can be installed on the equipment or interact with it through the network interface provided by the equipment to complete the overall testing of the machine.

[0083] The data acquisition and testing system is designed according to the product categories on the shelf. The overall design of the control area inspection equipment is as follows: Figure 2 As shown.

[0084] like Figure 1 As shown, the screw plate 7 is connected between the two-dimensional scanning mechanism 1 and the marble platform 4 to achieve fixation between the two-dimensional scanning mechanism 1 and the marble platform 4.

[0085] The horizontal adjustment shim is used to adjust the multi-tooth indexing stage 2 and the two-dimensional scanning mechanism 1 to be parallel. The thickness of the horizontal adjustment shim is between 0.001 mm and 0.05 mm.

[0086] The photoelectric autocollimator in this embodiment has ultra-high fixed-point accuracy and dynamic uniform speed acquisition at a certain frequency. After adding a multi-tooth indexing stage for rotatable angle measurement, the combined attributes can meet the requirements of ultra-high fixed-point accuracy, dynamic acquisition, and wide-range angle measurement. Its multi-tooth indexing stage has excellent flatness and angle measurement accuracy.

[0087] The aforementioned two-dimensional scanning mechanism's large-range, high-precision angle measurement accuracy testing device is constructed around the device under test (i.e., the two-dimensional scanning mechanism 1). The angle rotation of the photoelectric autocollimator 3 can be achieved through the multi-tooth indexing stage 2. This device enables high-precision, wide-field-of-view testing within 1 arcsecond around the device under test. The large-range angle measurement accuracy testing method includes static calibration measurement and dynamic calibration measurement methods. The static calibration measurement method further includes large-cycle angle accuracy calibration measurement and small-cycle angle accuracy calibration measurement.

[0088] Large-cycle angle accuracy calibration measurement of a wide-range angle sensing synchronizer with two channels experiencing slow deviation due to manufacturing errors.

[0089] The small-cycle angle accuracy calibration measurement mainly tests the accuracy of each electrical cycle of the high-resolution external channel of the inductive synchro.

[0090] Specifically, we selected a two-dimensional scanning mechanism 1 weighing approximately 100 kg as the device under test. This two-dimensional scanning mechanism 1 uses a 360-pair pole induction synchronizer, and its high-precision external channel consists of 360 identical 1-degree cycles.

[0091] The specific method for high-precision detection of 2D scanning mechanism 1 using the aforementioned 2D scanning mechanism large-area high-precision angle measurement accuracy detection device is as follows:

[0092] Step 1: Use the horizontal adjustment shims to adjust the perpendicularity of the photoelectric autocollimator to the mirror of the two-dimensional scanning mechanism, determine the angle measurement range, and repeat the pointing until the pitch error value of the angle measurement range is adjusted to less than or equal to 1″.

[0093] For example, the angle measurement range is determined to be ±20 degrees (i.e., the pointing range of the two-dimensional scanning mechanism 1 during angle measurement is ±1200′); the specific method for adjusting the pitch error within the ±20 degree angle measurement range is as follows:

[0094] The ground inspection unit sends a command to point to -20 degrees, uses a multi-tooth indexing table to move to -20 degrees and records the current pitch value, then points to 20 degrees and records the current pitch value again. The pitch value error within the ±20 degree range is compared, and the horizontal adjustment shims are used for adjustment. The process is repeated until the pitch error within the ±20 degree range is adjusted to less than 1″.

[0095] Step 2: Perform static calibration, including the following steps:

[0096] Step 2.1: Perform large-cycle angle accuracy calibration: The pointing range of the two-dimensional scanning mechanism is ±1200′ (i.e., ±20 degrees of the sensor synchronizer). The measurement is performed at 5′ intervals, with a total of 480 measurement points to complete the angle calibration of the sensor synchronizer within a 40-degree range.

[0097] Specifically, the method for calibrating the accuracy of the inductive synchro within a 40-degree range for measuring large-cycle angles in step 2.1 is as follows:

[0098] Step 2.1.1: Point the two-dimensional scanning mechanism to -20 degrees, move the multi-tooth indexing stage to +20 degrees, adjust the pitch error of the light spot field of view center to within ±1 arcsecond, and determine this as the starting point. The current starting point photoelectric autocollimator is recalibrated to 0°0′0″. Record the current data values ​​of the current inductive synchronizer and the photoelectric autocollimator;

[0099] Step 2.1.2: Then, rotate the two-dimensional scanning mechanism at 5' intervals while simultaneously rotating the multi-scale indexing table in the opposite direction. Both the two-dimensional scanning mechanism and the multi-scale indexing table rotate 5' each time, and the results are tested and recorded sequentially. A total of 480 sets of data values ​​were collected from the inductive synchro and photoelectric autocollimator; tests were conducted every 5 minutes. This represents the difference between two test data points of the photoelectric autocollimator; the aforementioned rotating two-dimensional scanning mechanism refers to the change in the pointing angle of the two-dimensional scanning mechanism.

[0100] The value is calculated as follows:

[0101] After the multi-tooth indexing table completes its rotation and locks, wait 5 seconds for it to stabilize, then start collecting data from the photoelectric autocollimator for 1 second and perform averaging to obtain photoelectric autocollimator data A.

[0102]

[0103] N represents the number of data acquisitions, and ai represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value.

[0104] After the multi-tooth indexing table completes its rotation and locks, waits 5 seconds for stabilization, and then begins acquiring data from the photoelectric autocollimator for 1 second. This data is then averaged to obtain photoelectric autocollimator data B, followed by 5 seconds of stationary data acquisition.

[0105]

[0106] N represents the number of data acquisitions, and bi represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value.

[0107] The difference between photoelectric autocollimator data A and photoelectric autocollimator data B is denoted as

[0108]

[0109] For example, in the static test for large-cycle angle accuracy calibration, the first photoelectric autocollimator data A measurement is 0°0′0″. Then, the two-dimensional scanning mechanism rotates 5′, while the multi-scale indexing table rotates 5′ in the opposite direction, resulting in the second photoelectric autocollimator data B measurement of 0°0′1″. The error of the two-dimensional scanning mechanism in the two tests can be obtained. It is BA=0°0′1″-0°0′0″=1″.

[0110] Step 2.1.3: Measure steps 2.1.1 to 2.1.2 a total of 3 times according to repeatability requirements.

[0111] Step 2.2: Perform small-cycle angle accuracy calibration measurement: Select up to 6 1-degree intervals of the inductive synchronizer, and calibrate the angle of each 1-degree interval in turn; with an interval of 2.5″, a total of 24 measurement points are used to complete the 1-degree range angle calibration of the inductive synchronizer;

[0112] Specifically, the method for calibrating the angle within a 1-degree range of the inductive synchronizer in step 2.2 is as follows:

[0113] Step 2.2.1: Point the two-dimensional scanning mechanism at n degrees, where n is greater than or equal to 0. Move the multi-tooth indexing stage to n degrees, align it with the optical axis, and acquire the current data of the photoelectric autocollimator. Adjust the center of the light spot field of view to within ±1 arcsecond to determine the starting point. Recalibrate the photoelectric autocollimator at the current starting point to 0°0′0. Record the current data values ​​of the current induction synchronizer and the photoelectric autocollimator.

[0114] Step 2.2.2: Rotate the 2D scanning mechanism at 2.5″ intervals while simultaneously rotating the multi-scale indexing table in the opposite direction. Both the 2D scanning mechanism and the multi-scale indexing table rotate 2.5″ each time. Test and record the results sequentially at 2.5″ intervals. A total of 24 sets of data were collected from the inductive synchro and photoelectric autocollimator; tests were conducted every 2.5″ interval. This represents the difference between the two data points from the photoelectric autocollimator during the two tests.

[0115] The value is calculated as follows:

[0116] After the multi-tooth indexing table completes its rotation and locks, wait 5 seconds for stabilization, then begin acquiring data from the photoelectric autocollimator for 1 second, and perform averaging to obtain photoelectric autocollimator data A:

[0117]

[0118] N represents the number of data acquisitions, and ai represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value.

[0119] After the multi-tooth indexing table completes its rotation and locks, waits 5 seconds for stabilization, and then begins acquiring data from the photoelectric autocollimator for 1 second. This data is then averaged to obtain photoelectric autocollimator data B, followed by 5 seconds of stationary data acquisition.

[0120]

[0121] N represents the number of data acquisitions, and bi represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value.

[0122] The difference between photoelectric autocollimator data A and photoelectric autocollimator data B is denoted as

[0123]

[0124] Step 2.2.3: Perform the measurements from Step 2.2.1 to Step 2.2.2 a total of 3 times according to the repeatability requirements.

[0125] We can select six consecutive 1-degree ranges for small-cycle angle accuracy calibration measurements of the inductive synchro, such as the 0-6 degree range. Following step 2.2, we sequentially measure the data values ​​of the inductive synchro and the photoelectric autocollimator in the ranges of 0 to 1 degree, 1 to 2 degrees, 2 to 3 degrees, 3 to 4 degrees, 4 to 5 degrees, and 5 to 6 degrees. n is equal to the minimum value within the measured 1-degree range. For example, when performing small-cycle angle accuracy calibration measurements on the inductive synchro in the 0 to 1 degree range, n = 0; when performing small-cycle angle accuracy calibration measurements on the 1 to 2 degree range, n = 1, and so on.

[0126] Step 3: Perform dynamic accuracy calibration, including the following steps:

[0127] Step 3.1: The ground inspection calculates the distance the two-dimensional scanning mechanism travels into the uniform speed segment during its movement, and calculates the distance to reach the field of view of the photoelectric autocollimator. When it reaches the field of view of the photoelectric autocollimator, the ground inspection sends a synchronization flag to the acquisition angle computer to synchronize the initial measurement time of the photoelectric autocollimator and the ground inspection, and align the field of view coverage.

[0128] Step 3.2: The ground inspection sends a low-speed uniform scanning command to the control box of the two-dimensional scanning mechanism, and the two-dimensional scanning mechanism begins to point and scan.

[0129] Step 3.3: After the two-dimensional scanning mechanism reaches a constant speed, when it reaches the field of view of the photoelectric autocollimator, the ground detection feedback flag is sent to the acquisition angle computer for acquisition.

[0130] Step 3.4: Record the measured position and time of entering the field of view of the photoelectric autocollimator, and at the same time record the position and time of the induction synchronizer.

[0131] Step 3.5: Control the two-dimensional scanning mechanism to complete the acquisition of the full field of view position of the photoelectric autocollimator. Repeat steps 3.2 to 3.4 to complete the acquisition of three sets of autocollimator data at the same angle and confirm the repeatability of the test data.

[0132] Step 3.6: Rotate the multi-tooth indexing table 1000″ and repeat steps 3.1 to 3.5.

[0133] The dynamic calibration method requires controlling the two-dimensional scanning mechanism to complete a low-speed uniform scan within the field of view of the photoelectric autocollimator.

[0134] Specifically, in the dynamic accuracy calibration process of step 3, the acceleration curve of the fixed two-dimensional scanning mechanism is set according to the algorithm. Different acceleration distances are required according to different speeds. In the current test acquisition, the two-dimensional scanning mechanism needs to perform a slow, uniform scan at an ultra-low speed. The scanning speed of the two-dimensional scanning mechanism is set to 0.003 degrees per second. The photoelectric autocollimator performs test acquisition of the current scanning process at a frequency of 60 Hz.

[0135] The acceleration speed of the scanning control system is 0.003 degrees per second, the control frequency is 200 Hz, and the acceleration time is 2 beats, i.e., 100 Hz, to obtain the degree of movement.

[0136] L = 1 / 2VT

[0137] V represents the current scanning speed, for example, 0.003 degrees per second; T represents the acceleration time, for example, 0.1 seconds for 2-beat acceleration, i.e., 100 Hz; L represents the degree of movement of the 2D scanning mechanism during the acceleration phase, i.e., the angular distance of movement of the 2D scanning mechanism during the acceleration phase, for example: L = 1 / 2 * 0.003 * 0.1 = 0.00015 degrees.

[0138] Then convert the degree of movement to arcseconds for easier unit standardization.

[0139] D = L * 3600

[0140] D is L after converting degrees to arcseconds. For example: D = 0.00015 * 3600 = 0.54 arcseconds.

[0141] The angular distance of the acceleration phase is confirmed to be D. A time of D plus 0.1 arcseconds is allowed for the start-up time of the photoelectric autocollimator's dynamic acquisition. After passing through an angle of D, when the ground detector reaches a constant speed, a feedback flag is sent to the acquisition angle computer to start acquisition. After another 0.1 seconds, the data enters the field of view of the photoelectric autocollimator and is collected and stored.

[0142] During the dynamic accuracy calibration process, in order to ensure the accuracy of data acquisition alignment, it is necessary to meet the precise interconnection between the current servo control system and the photoelectric autocollimator acquisition computer, ensure that the time error is less than 25ns, and align the servo error and angle information of the control algorithm with the sampling frequency of the photoelectric autocollimator.

[0143] Of course, to ensure the accuracy of subsequent angle calibration measurements, we can also clean all screws used in the entire assembly process, including those on the marble platform 4, the bottom of the 2D scanning mechanism 1, the bottom of the multi-tooth indexing table 2, the horizontal adjustment shims, the photoelectric autocollimator mounting fixture 3, and the screw plate 7, by soaking them in alcohol and then using a lint-free cloth. After cleaning, we can then proceed according to... Figure 1The assembly and testing device is shown. A level and micrometer are used to confirm the flatness. At the same time, before the test begins, all test cables are connected and the equipment is confirmed to be working properly. The photoelectric autocollimator 3 can receive the mirror reflection value of the two-dimensional pointing mechanism 1.

[0144] Through the above steps, we completed the static and dynamic accuracy calibration of the two-dimensional scanning mechanism 1. Furthermore, in the static accuracy calibration, we completed the 5′ interval large-cycle angle accuracy calibration measurement within the angular measurement range (within ±20 degrees of the inductive synchronizer) and the inductive synchronizer's up to 6 1-degree interval 2.5″ interval small-cycle angle accuracy calibration measurements.

Claims

1. A two-dimensional scanning mechanism with a wide range of high-precision angle measurement accuracy detection device, characterized in that: Includes a two-dimensional scanning mechanism, a multi-tooth indexing stage, an optoelectronic autocollimator, a marble platform with a flatness of 0 or higher, an angle acquisition circuit, a motion control box, a screw plate, a horizontal adjustment shim, an optoelectronic autocollimator mounting fixture, an angle acquisition computer, and a ground inspection unit; The two-dimensional scanning mechanism and the multi-tooth indexing stage are placed on a marble platform. The photoelectric autocollimator mounting fixture is installed on the multi-tooth indexing stage, and the photoelectric autocollimator is mounted on the photoelectric autocollimator mounting fixture. Horizontal adjustment shims are used to adjust the multi-tooth indexing stage and the two-dimensional scanning mechanism to be parallel. This ensures that the photoelectric autocollimator can receive the specular reflection value of the two-dimensional pointing mechanism. The angle acquisition circuit is connected to the motion control box. The motion control box is connected to the ground sensor, the photoelectric autocollimator is connected to the angle acquisition computer, and the ground sensor is connected to the angle acquisition computer via cables. The flatness of the multi-tooth indexing table is 0.01 mm, the absolute accuracy of 360 degrees is 0.5″, and the accuracy within the measured range of 40 degrees is 0.2″. The photoelectric autocollimator has an absolute angle measurement accuracy of 0.1″, a repeatability better than 0.04″, a resolution of 0.001″, a field of view of 3000″*3000″, a dynamic angle measurement data acquisition speed of 60Hz, and a high-speed acquisition speed of 1kHz. The angle acquisition circuit is used to collect the position change of the inductive synchronizer. The angle conversion frequency is 64kHz, the resolution is 0.05″, and the stability is better than 0.1″. The motion control box is used to acquire the position information of the angle acquisition circuit and control the motor of the two-dimensional scanning mechanism, with a scanning control accuracy better than 0.2″. The angle acquisition computer is used to connect to the angle change value of the photoelectric autocollimator, and the angle change is stored in the angle acquisition computer. The ground sensor is used to send commands to the motion control box, causing the two-dimensional scanning mechanism to point for scanning; the ground sensor is also used to collect position information of the angle acquisition circuit and current and motion mode data of the motion control box, and its acquisition frequency supports up to 10MHz.

2. The two-dimensional scanning mechanism large-range high-precision angle measurement accuracy detection device according to claim 1, characterized in that: The thickness of the leveling shim is between 0.001 mm and 0.05 mm.

3. A method for detecting the high-precision angle measurement accuracy of a two-dimensional scanning mechanism over a wide range, characterized in that: The large-range, high-precision angle measurement accuracy detection device using the two-dimensional scanning mechanism described in claim 1 or 2 specifically includes the following steps: Step 1: Use the horizontal adjustment shims to adjust the perpendicularity of the photoelectric autocollimator to the mirror of the two-dimensional scanning mechanism, determine the angle measurement range, and repeat the pointing until the pitch error value of the angle measurement range is adjusted to less than or equal to 1″. Step 2: Perform static calibration, including the following steps: Step 2.1: Perform large-cycle angle accuracy calibration: Perform angle calibration to determine the angle measurement range at 5′ intervals; Step 2.2: Perform small-cycle angle accuracy calibration measurement: Select up to 6 1-degree intervals of the inductive synchronizer, and calibrate the angle of each 1-degree interval in turn; with an interval of 2.5″, a total of 24 measurement points are used to complete the 1-degree range angle calibration of the inductive synchronizer; Step 3: Perform dynamic accuracy calibration, including the following steps: Step 3.1: The ground inspection calculates the distance the two-dimensional scanning mechanism travels into the uniform speed segment during its movement, and calculates the distance to reach the field of view of the photoelectric autocollimator. When it reaches the field of view of the photoelectric autocollimator, the ground inspection sends a synchronization flag to the acquisition angle computer to synchronize the initial measurement calibration time of the photoelectric autocollimator and the ground inspection, and align the field of view coverage. Step 3.2: The ground inspection sends a low-speed uniform scanning command to the control box of the two-dimensional scanning mechanism, and the two-dimensional scanning mechanism begins to point and scan; Step 3.3: After the two-dimensional scanning mechanism reaches a constant speed, when it reaches the field of view of the photoelectric autocollimator, the ground detection feedback flag is sent to the acquisition angle computer for acquisition. Step 3.4: Record the measured position and time of entering the field of view of the photoelectric autocollimator, and at the same time record the position and time of the induction synchronizer; Step 3.5: Control the two-dimensional scanning mechanism to complete the acquisition of the full field of view position of the photoelectric autocollimator. Repeat steps 3.2 to 3.4 to complete the acquisition of three sets of autocollimator data at the same angle and confirm the repeatability of the test data. Step 3.6: Rotate the multi-tooth indexing table 1000″ and repeat steps 3.1 to 3.

5.

4. The method for detecting the large-range, high-precision angle measurement accuracy of a two-dimensional scanning mechanism according to claim 3, characterized in that: In step 1, the angle measurement range is ±20 degrees, that is, the pointing range of the two-dimensional scanning mechanism is ±1200′; the specific method for adjusting the pitch error within the ±20 degree angle measurement range is as follows: The ground inspection unit sends a command to point to -20 degrees, uses a multi-tooth indexing table to move to -20 degrees and records the current pitch value, then points to 20 degrees and records the current pitch value again. The pitch value error within the ±20 degree range is compared, and the horizontal adjustment shims are used for adjustment. The process is repeated until the pitch error within the ±20 degree range is adjusted to less than 1″.

5. The method for detecting the large-range, high-precision angle measurement accuracy of a two-dimensional scanning mechanism according to claim 4, characterized in that: In step 2.1, the angle measurement range is ±20 degrees. The specific method for calibrating the accuracy of the large-cycle angle within a 40° range using the inductive synchronizer is as follows: Step 2.1.1: Point the two-dimensional scanning mechanism to -20 degrees, move the multi-tooth indexing stage to +20 degrees, adjust the pitch error of the light spot field of view center to within ±1 arcsecond, and determine this as the starting point. The current starting point photoelectric autocollimator is recalibrated to 0°0′0″. Record the current data values ​​of the current inductive synchronizer and the photoelectric autocollimator; Step 2.1.2: Then, rotate the two-dimensional scanning mechanism at 5' intervals while simultaneously rotating the multi-scale indexing table in the opposite direction. Both the two-dimensional scanning mechanism and the multi-scale indexing table rotate 5' each time, and the results are tested and recorded sequentially. A total of 480 sets of data values ​​were collected from the inductive synchro and photoelectric autocollimator; tests were conducted every 5 minutes. The difference between two test data points of the photoelectric autocollimator; The value is calculated as follows: After the multi-tooth indexing table completes its rotation and locks, wait 5 seconds for it to stabilize, then start collecting data from the photoelectric autocollimator for 1 second and perform averaging to obtain photoelectric autocollimator data A. N represents the number of data acquisitions, and ai represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value. After the multi-tooth indexing table completes its rotation and locks, waits 5 seconds for stabilization, and then begins acquiring data from the photoelectric autocollimator for 1 second. This data is then averaged to obtain photoelectric autocollimator data B, followed by 5 seconds of stationary data acquisition. N represents the number of data acquisitions, and bi represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value. The difference between photoelectric autocollimator data A and photoelectric autocollimator data B is denoted as Step 2.1.3: Measure steps 2.1.1 to 2.1.2 a total of 3 times according to repeatability requirements.

6. The method for detecting the large-range, high-precision angle measurement accuracy of a two-dimensional scanning mechanism according to claim 5, characterized in that: In step 2.2, the specific method for calibrating the angle within a 1-degree range of the inductive synchronizer is as follows: Step 2.2.1: Point the two-dimensional scanning mechanism at n degrees, where n is greater than or equal to 0. Move the multi-tooth indexing stage to n degrees, align it with the optical axis, and acquire the current data of the photoelectric autocollimator. Adjust the center of the light spot field of view to within ±1 arcsecond to determine the starting point. Recalibrate the photoelectric autocollimator at the current starting point to 0°0′0. Record the current data values ​​of the current induction synchronizer and the photoelectric autocollimator. Step 2.2.2: Rotate the 2D scanning mechanism at 2.5″ intervals while simultaneously rotating the multi-scale indexing table in the opposite direction. Both the 2D scanning mechanism and the multi-scale indexing table rotate 2.5″ each time. Test and record the results sequentially at 2.5″ intervals. A total of 24 sets of data were collected from the inductive synchro and photoelectric autocollimator; tests were conducted every 2.5 seconds. This represents the difference between two data points from the photoelectric autocollimator during two separate tests. The value is calculated as follows: After the multi-tooth indexing table completes its rotation and locks, wait 5 seconds for it to stabilize, then start collecting data from the photoelectric autocollimator for 1 second and perform averaging to obtain photoelectric autocollimator data A. N represents the number of data acquisitions, and ai represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value. After the multi-tooth indexing table completes its rotation and locks, waits 5 seconds for stabilization, and then begins acquiring data from the photoelectric autocollimator for 1 second. This data is then averaged to obtain photoelectric autocollimator data B, followed by 5 seconds of stationary data acquisition. N represents the number of data acquisitions, and bi represents the acquired data, which is calculated by the internal computer of the photoelectric autocollimator to obtain the average value. The difference between photoelectric autocollimator data A and photoelectric autocollimator data B is denoted as Step 2.2.3: Perform the measurements from Step 2.2.1 to Step 2.2.2 a total of 3 times according to the repeatability requirements.

7. The method for detecting the large-range, high-precision angle measurement accuracy of a two-dimensional scanning mechanism according to claim 6, characterized in that: In the dynamic accuracy calibration process in step 3, the acceleration curve of the fixed two-dimensional scanning mechanism is set according to the algorithm. Different acceleration distances are required according to different speeds. In the current test acquisition, the two-dimensional scanning mechanism needs to perform a slow, uniform scan at an ultra-low speed. The scanning speed of the two-dimensional scanning mechanism is set to 0.003 degrees per second. The photoelectric autocollimator performs test acquisition of the current scanning process at a frequency of 60 Hz. The scanning control system accelerates at a rate of 0.003 degrees per second, with a control frequency of 200 Hz. The acceleration time is calculated as 2 beats (100 Hz) to obtain the degree of movement. L = 1 / 2VT V represents the current scanning speed of the 2D scanning mechanism, in degrees per second; T represents the acceleration time of the 2D scanning mechanism, in seconds; L represents the degree of movement of the 2D scanning mechanism during the acceleration phase, i.e., the angular distance moved by the 2D scanning mechanism during the acceleration phase, in degrees. Then convert the degree of movement to arcseconds for easier unit standardization: D = L * 3600 D represents the angular distance traveled by the acceleration segment of the two-dimensional scanning mechanism, in arcseconds. The angular distance of the acceleration phase is confirmed to be D. A time of D plus 0.1 arcseconds is allowed for the start-up time of the photoelectric autocollimator's dynamic acquisition. After passing through an angle of D, when the ground detector reaches a constant speed, a feedback flag is sent to the acquisition angle computer to start acquisition. After another 0.1 seconds, the data enters the field of view of the photoelectric autocollimator and is collected and stored.

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