Large-range high-precision angle measurement precision detection device and method for two-dimensional scanning mechanism

Abstract

The invention discloses a large-range high-precision angle measurement precision detection device and method for a two-dimensional scanning mechanism. The detection device comprises a two-dimensional scanning mechanism, a multi-tooth indexing table, a photoelectric autocollimator, a marble platform, an angle acquisition circuit, a motion control box, a screw flat plate, a horizontal adjusting gasket, a photoelectric autocollimator mounting tool, an angle acquisition computer, a ground detector and the like. The multi-tooth indexing table is placed on the marble platform plane; the photoelectric autocollimator is mounted on the multi-tooth indexing table through the photoelectric autocollimator mounting tool; a horizontal adjusting gasket is used for adjusting the multi-tooth indexing table and the two-dimensional scanning mechanism to be consistent in parallelism; it is ensured that the photoelectric autocollimator can receive the specular reflection value of the two-dimensional pointing mechanism. The detection method comprises static calibration and dynamic calibration, wherein the static calibration comprises large-period angle precision calibration and small-period angle precision calibration measurement. The invention provides a third-party angle measuring device and a third-party angle measuring method. The third-party angle measuring device can be unfolded around measured equipment and can reach within one arc second.

Description

Technical Field

[0001] The present invention relates to the field of large-scale high-precision angle measurement detection devices and calibration technology, and in particular to a large-scale high-precision angle measurement accuracy detection device and method for a two-dimensional scanning mechanism. Background Art

[0002] As the motion control of two-dimensional scanning mechanisms becomes more refined, the requirements for angle measurement accuracy are becoming increasingly higher. Due to the large size and weight of two-dimensional scanning mechanisms, third-party angle measurement devices and methods that can achieve an accuracy of less than 1 arc second around the device under test are becoming increasingly important.

[0003] Currently, the main devices used for angle measurement include theodolites, gyroscopes, polygonal prisms, gyroscopes, and CCD arrays. High-resolution CCD arrays are limited by the scanning mechanism's requirement for highly flat mirrors, requiring different high-flatness mirrors for different inertias. Theodolites are limited by their own accuracy, with large fluctuations in reading range and failing to meet accuracy requirements. Polyhedral prisms are only suitable for static calibration. Gyroscopes exhibit a certain degree of offset during long-term testing, requiring regular alignment to prevent test data drift.

[0004] The above-mentioned existing angle measurement devices cannot meet the requirements of ultra-high precision fixed-point accuracy, dynamic uniform speed accuracy at a certain frequency, and long-term measurement stability, making it difficult to achieve measurement operations within 1 arc second around the device under test. Summary of the Invention

[0005] The purpose of the present invention is to provide a large-scale, high-precision angular measurement accuracy detection device and method for a two-dimensional scanning mechanism. In order to solve the angular measurement accuracy problem of the two-dimensional scanning mechanism, the present invention provides a third-party angular measurement device and method that can achieve an angle measurement accuracy of less than 1 arc second around the device being measured.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A device for detecting angle measurement accuracy of a two-dimensional scanning mechanism with high precision over a large range includes a two-dimensional scanning mechanism, a multi-tooth indexing table, a photoelectric autocollimator, a marble platform with a flatness of level 0 or above, an angle acquisition circuit, a motion control box, a screw plate, a level adjustment spacer, a photoelectric autocollimator installation tool, an angle acquisition computer, and a ground detector.

[0008] The 2D scanning mechanism and multi-tooth indexing table are placed on a marble platform. The photoelectric autocollimator mounting fixture is installed on the multi-tooth indexing table, and the photoelectric autocollimator is installed on the photoelectric autocollimator mounting fixture. Horizontal adjustment spacers are used to adjust the multi-tooth indexing table and the 2D scanning mechanism to be parallel. This ensures that the photoelectric autocollimator can receive the mirror reflection value of the 2D pointing mechanism. The angle acquisition circuit is connected to the motion control box. Cables are used to connect the motion control box to the ground detection system, the photoelectric autocollimator to the angle acquisition computer, and the ground detection system to the angle acquisition computer.

[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″, dynamic angle measurement data acquisition at 60hz, and high-speed acquisition at 1KHZ;

[0011] The angle acquisition circuit is used to collect the position changes 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 obtain the position information of the angle acquisition circuit and control the motor of the two-dimensional scanning mechanism. The scanning control accuracy is better than 0.2";

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

[0014] The ground detection is used to send instructions to the motion control box to make the two-dimensional scanning mechanism point to scan; the ground detection is also used to collect the position information of the angle acquisition circuit and the current and motion mode data of the motion control box. Its acquisition frequency supports up to 10Mhz.

[0015] Furthermore, the thickness of the level adjustment gasket 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 is provided, using the device for detecting the large-scale high-precision angle measurement accuracy of a two-dimensional scanning mechanism, and specifically comprises the following steps:

[0017] Step 1: Use the horizontal adjustment spacer to adjust the verticality of the photoelectric autocollimator and 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: complete the 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 six 1-degree intervals of the inductor and perform angle calibration for each 1-degree interval. Use 24 measurement points at 2.5-inch intervals to complete the 1-degree angle calibration of the inductor.

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

[0022] Step 3.1. The ground inspection system calculates the distance the two-dimensional scanning mechanism enters the uniform speed section during motion, and calculates the distance to the field of view of the photoelectric autocollimator. When the distance reaches the field of view of the photoelectric autocollimator, the ground inspection system sends a synchronization flag to the acquisition angle computer, synchronizing the measurement initial time of the photoelectric autocollimator and the ground inspection system, and aligning 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 starts pointing scanning;

[0024] Step 3.3: After the two-dimensional scanning mechanism reaches a uniform speed, when it reaches the field of view of the photoelectric autocollimator, a 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 also 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 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 to 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 pitch value error adjustment method within the ±20 degree angle measurement range is specifically as follows:

[0029] Send a command from the ground inspection station to point to -20 degrees. Use the multi-tooth indexing table to move to -20 degrees and record the current pitch value. Then point to 20 degrees and record the current pitch value. Compare the pitch value error within the ±20 degree range. Use the horizontal adjustment shims to make adjustments. Repeat the pointing 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, and the specific method for calibrating the large-cycle angle accuracy of the induction synchronizer measuring 40 degrees is as follows:

[0031] Step 2.1.1. Point the 2D scanning mechanism to -20 degrees, move the multi-tooth indexing table to +20 degrees, adjust the pitch error of the center of the spot field of view to within ±1 arc second, and determine it 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 photoelectric autocollimator;

[0032] Step 2.1.2, then rotate the 2D scanning mechanism at 5' intervals and simultaneously rotate the multi-scale indexing table in the opposite direction. The 2D scanning mechanism and the multi-scale indexing table rotate 5' each time, and test and record them in turn. The data values ​​of the induction synchronizer and the photoelectric autocollimator total 480 groups; a test is performed every 5', among which, The difference between the two test data before and after the photoelectric autocollimator;

[0033] The value is calculated as follows:

[0034] After the multi-tooth indexing table completes its rotation, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data A.

[0035]

[0036] N is the number of acquisitions, ai is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator;

[0037] After the multi-tooth indexing table completes its rotation again, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data B. The data is collected for 5 seconds at rest:

[0038]

[0039] N is the number of acquisitions, bi is the acquired data, and the average value is calculated by the acquisition computer in the photoelectric autocollimator;

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

[0041]

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

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

[0044] Step 2.2.1. Point the 2D scanning mechanism to n degrees, where n is greater than or equal to 0. Move the multi-tooth indexing stage to n degrees, align the optical axis, and obtain the current data from the photoelectric autocollimator. Adjust the center of the spot field of view to within ±1 arc second, and determine it as the starting point. Recalibrate the photoelectric autocollimator at the current starting point to 0°0′0, and record the current data values ​​of the induction synchronizer and the photoelectric autocollimator.

[0045] Step 2.2.2: Rotate the 2D scanning mechanism at 2.5″ intervals and simultaneously rotate the multi-scale indexing table in the opposite direction. The 2D scanning mechanism and multi-scale indexing table rotate 2.5″ each time. Test and record the results in 2.5″ intervals. The data values ​​of the induction synchronizer and the photoelectric autocollimator total 24 sets of data; a test is performed every 2.5″, among which, The difference between the two data of the photoelectric autocollimator during the two tests;

[0046] The value is calculated as follows:

[0047] After the multi-tooth indexing table completes its rotation, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data A.

[0048]

[0049] N is the number of acquisitions, ai is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator;

[0050] After the multi-tooth indexing table completes its rotation again, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data B. The data is collected for 5 seconds at rest:

[0051]

[0052] N is the number of acquisitions, bi is the acquired data, and the average value is calculated by the acquisition computer in the photoelectric autocollimator;

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

[0054]

[0055] Step 2.2.3: Measure steps 2.2.1 to 2.2.2 a total of three 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. The current test acquisition requires the two-dimensional scanning mechanism to scan at an ultra-low uniform speed. The scanning speed of the two-dimensional scanning mechanism is set to 0.003 degrees per second, and the photoelectric autocollimator tests and acquires the current scanning process at a frequency of 60 Hz.

[0057] 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, that is, 100 Hz, to obtain the movement degree:

[0058] L=1 / 2VT

[0059] V is the current scanning speed of the two-dimensional scanning mechanism, in degrees per second; T is the acceleration time of the two-dimensional scanning mechanism, in seconds; L is the degree of movement of the two-dimensional scanning mechanism in the acceleration phase, that is, the angular distance moved by the two-dimensional scanning mechanism in the acceleration phase, in degrees;

[0060] Then convert the movement degrees into arc seconds to facilitate unit unification:

[0061] D=L*3600

[0062] D is the angular distance moved by the acceleration section of the two-dimensional scanning mechanism, in arc seconds;

[0063] Confirm that the angular distance of the acceleration section is D, and set aside D plus 0.1 arc seconds for the start time of the photoelectric autocollimator dynamic acquisition. After D angles, when the ground detection reaches a uniform speed, a feedback flag is given to the acquisition angle computer to start acquisition. After another 0.1 seconds, it enters the field of view of the photoelectric autocollimator to collect and access data.

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

[0065] This patent involves a large-range angular measurement calibration method for a photoelectric autocollimator based on a multi-tooth dividing table. It aims to achieve effective calibration of the large-range angular 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] The photoelectric autocollimator in this invention possesses excellent angular measurement performance, with an absolute angular measurement accuracy of 0.1″, a repeatability better than 0.04″, a resolution of up to 0.001″, and a field of view of only 3000″ (approximately 0.833°). To accurately calibrate the autocollimator's angular measurement accuracy over a wide range, a multi-tooth indexing table is used as the core calibration reference device.

[0067] This multi-tooth dividing table has high-precision characteristics: its flatness is 0.01 mm, which can provide 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", which can support angle calibration expansion within the full range; most importantly, its accuracy within the 40-degree measurement range is 0.2", which completely covers the 3000" field of view of the photoelectric autocollimator, and the accuracy level is reasonably matched with the absolute angular measurement accuracy of the autocollimator (0.1"), which can provide a reliable standard angle reference for calibration. Through the above method, with the help of the high precision of 0.2" within the range of 40 degrees, the absolute precision of 0.5" within the range of 360 degrees, and the flatness of 0.01 mm of the multi-tooth dividing table, the large-scale angular measurement calibration of large-scale two-dimensional scanning mechanisms can be accurately completed. In terms of accuracy and uncertainty calculation, according to the principle of tripling the absolute measurement error, the measurement uncertainty corresponding to the absolute angular measurement accuracy of 0.1" of the photoelectric autocollimator is 0.2", and the measurement uncertainty corresponding to the 0.2" within the range of 40 degrees of the multi-tooth dividing table is 0.4". The total error of the final comprehensive measurement result is controlled at 0.9", so the final measurement accuracy can meet the calibration requirements within 1 arc second. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a structural schematic diagram of the large-scale high-precision angle measurement accuracy detection device of the two-dimensional scanning mechanism in the present invention.

[0069] In the picture:

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

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

[0072] In the figure: describes the communication method between the motion control box and the ground detection and the function of the ground detection. DETAILED DESCRIPTION

[0073] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0074] like Figure 1As shown in the figure, it is a structural diagram of a large-scale high-precision angle measurement accuracy detection device for a two-dimensional scanning mechanism. In this embodiment, the large-scale high-precision angle measurement accuracy detection device for a two-dimensional scanning mechanism includes a two-dimensional scanning mechanism 1, a multi-tooth indexing table 2, a photoelectric autocollimator 3, a marble platform 4 with a flatness of level 0 or above, an angle acquisition circuit 5, a motion control box 6, a screw plate 7, a horizontal adjustment gasket, a photoelectric autocollimator installation tooling 8, an angle acquisition computer 9 and a ground detection.

[0075] The angle acquisition circuit 5, motion control box 6, 2D scanning mechanism 1, and multi-tooth indexing table 2 are placed on the marble platform 4. The photoelectric autocollimator mounting fixture 8 is mounted on the multi-tooth indexing table 2, and the photoelectric autocollimator 3 is mounted on the photoelectric autocollimator mounting fixture 8. Using horizontal adjustment shims, the multi-tooth indexing table 2 and 2D scanning mechanism 1 are aligned parallel to each other, ensuring that the photoelectric autocollimator 3 can receive the mirror reflection value of the 2D pointing mechanism 1. The angle acquisition circuit 7 is connected to the motion control box 6. Cables connect the motion control box 6 to the ground detector, the photoelectric autocollimator 3 to the angle acquisition computer 9, and the ground detector to the angle acquisition computer 9. The ground detector is placed away from the 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 inductive synchronizer, with an angle conversion frequency of 64 kHz, 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 obtain the position information of the angle acquisition circuit and control the motor of the two-dimensional scanning mechanism 1, and the scanning control accuracy is better than 0.2".

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

[0081] The ground detection (i.e., the host computer that sends and receives instructions) is used to send instructions to the motion control box 6 to make the two-dimensional scanning mechanism 1 point to scan; the ground detection is also used to collect the position information of the angle acquisition circuit and the current and motion mode data of the motion control box; the acquisition frequency of the ground detection is adjustable and can support up to 10Mhz. For example, an 8khz acquisition frequency can be selected during measurement.

[0082] The ground inspection equipment is based on a universal ground test platform. It utilizes a standard PCIE service platform and incorporates various universal I / O modules to meet the requirements of various test application environments. Designed using proven server equipment as its foundation, it comprises custom-designed universal test modules (RS422 interface card, digital I / O interface card, and AD interface card) and supporting custom embedded software. A unified power supply module is installed within the chassis to provide power to all modules, using an AC power supply. Testing software can be installed on the equipment itself or interacted with through the device's network interface to complete the entire system test.

[0083] The data acquisition and testing system is designed according to the classification of shelf products. The overall design of the control ground inspection equipment is shown in Figure 2 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 gasket is used to adjust the multi-tooth indexing table 2 and the two-dimensional scanning mechanism 1 to be in parallel. The thickness of the horizontal adjustment gasket is between 0.001 mm and 0.05 mm.

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

[0087] The above-mentioned large-scale, high-precision angular measurement accuracy testing device for a two-dimensional scanning mechanism is constructed around the device under test (i.e., the two-dimensional scanning mechanism 1). The angular rotation of the photoelectric autocollimator 3 is achieved via a multi-tooth indexing table 2. This device can perform high-precision, wide-field-of-view tests within 1 arc second around the device under test. The two-dimensional scanning mechanism's large-scale angular measurement accuracy testing method includes both static and dynamic calibration measurement methods. The static calibration measurement method further includes large-cycle angular accuracy calibration measurement and small-cycle angular accuracy calibration measurement.

[0088] Large cycle angle accuracy calibration measures the slow deviation of two channels of a wide range of angle sensing synchronizers caused by process errors.

[0089] The small cycle angle accuracy calibration measurement mainly tests the accuracy of each electrical cycle of the high resolution of the induction synchronizer's external channel.

[0090] Specifically, we selected a two-dimensional scanning mechanism 1 weighing about 100 kg as the device under test. The two-dimensional scanning mechanism 1 adopts a 360-pole inductive synchronizer, and its high-precision outer channel consists of 360 identical 1-degree periods.

[0091] The high-precision detection method for the two-dimensional scanning mechanism 1 using the large-scale high-precision angle measurement accuracy detection device of the two-dimensional scanning mechanism is as follows:

[0092] Step 1: Use the horizontal adjustment spacer to adjust the verticality of the photoelectric autocollimator and the two-dimensional scanning mechanism mirror, 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 pitch value error adjustment method within the ±20 degree angle measurement range is as follows:

[0094] Send a command from the ground inspection station to point to -20 degrees. Use the multi-tooth indexing table to move to -20 degrees and record the current pitch value. Then point to 20 degrees and record the current pitch value. Compare the pitch value error within the ±20 degree range. Use the horizontal adjustment shims to make adjustments. Repeat the pointing 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 for the induction synchronizer). The measurement is performed at 5' intervals, with a total of 480 measurement points to complete the 40-degree angle calibration of the induction synchronizer.

[0097] Specifically, the specific method for calibrating the large-cycle angle accuracy of the induction synchronizer within a 40-degree range in step 2.1 is as follows:

[0098] Step 2.1.1. Point the 2D scanning mechanism to -20 degrees, move the multi-tooth indexing table to +20 degrees, adjust the pitch error of the center of the spot field of view to within ±1 arc second, and determine it 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 photoelectric autocollimator;

[0099] Step 2.1.2, then rotate the 2D scanning mechanism at 5' intervals and simultaneously rotate the multi-scale indexing table in the opposite direction. The 2D scanning mechanism and the multi-scale indexing table rotate 5' each time, and test and record them in turn. The data values ​​of the induction synchronizer and the photoelectric autocollimator total 480 groups; a test is performed every 5', among which, is the difference between the two test data of the photoelectric autocollimator; the above-mentioned rotation of the two-dimensional scanning mechanism means that the pointing angle of the two-dimensional scanning mechanism changes.

[0100] The value is calculated as follows:

[0101] After the multi-tooth indexing table completes its rotation, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data A.

[0102]

[0103] N is the number of acquisitions, ai is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator;

[0104] After the multi-tooth indexing table completes its rotation again, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data B. The data is collected for 5 seconds at rest:

[0105]

[0106] N is the number of acquisitions, bi is the acquired data, and the average value is calculated by the acquisition computer in the photoelectric autocollimator;

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

[0108]

[0109] For example, in the static test, the first photoelectric autocollimator data A is measured as 0°0′0″ in the large cycle angle accuracy calibration. Then the two-dimensional scanning mechanism is rotated 5′, and the multi-scale indexing table is rotated 5′ in the opposite direction to obtain the second photoelectric autocollimator data B measurement as 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 three times according to the repeatability requirements.

[0111] Step 2.2: Perform small-cycle angle accuracy calibration measurement: Select up to six 1-degree intervals of the inductor and perform angle calibration for each 1-degree interval. Use 24 measurement points at 2.5-inch intervals to complete the 1-degree angle calibration of the inductor.

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

[0113] Step 2.2.1. Point the 2D scanning mechanism to n degrees, where n is greater than or equal to 0. Move the multi-tooth indexing stage to n degrees, align the optical axis, and obtain the current data from the photoelectric autocollimator. Adjust the center of the spot field of view to within ±1 arc second, and determine it as the starting point. Recalibrate the photoelectric autocollimator at the current starting point to 0°0′0, and record the current data values ​​of the induction synchronizer and the photoelectric autocollimator.

[0114] Step 2.2.2: Rotate the 2D scanning mechanism at 2.5″ intervals and simultaneously rotate the multi-scale indexing table in the opposite direction. The 2D scanning mechanism and multi-scale indexing table rotate 2.5″ each time. Test and record the results in 2.5″ intervals. The data values ​​of the induction synchronizer and the photoelectric autocollimator total 24 sets of data; a test is performed every 2.5″ interval, among which, It is the difference between the two data of the photoelectric autocollimator during the two tests.

[0115] The value is calculated as follows:

[0116] After the multi-tooth indexing table completes its rotation, it is locked and waits for 5 seconds for stabilization. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data A:

[0117]

[0118] N is the number of acquisitions, ai is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator.

[0119] After the multi-tooth indexing table completes its rotation again, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data B. The data is collected for 5 seconds at rest:

[0120]

[0121] N is the number of acquisitions, bi is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator.

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

[0123]

[0124] Step 2.2.3: Measure steps 2.2.1 to 2.2.2 a total of three times according to the repeatability requirements.

[0125] We can select six consecutive 1-degree ranges for the induction synchronizer to perform small-cycle angular accuracy calibration measurements, such as the 0-6 degree range. Following step 2.2, we can successively measure the induction synchronizer and photoelectric autocollimator data values ​​for the 0-1 degree range, the 1-2 degree range, the 2-3 degree range, the 3-4 degree range, the 4-5 degree range, and the 5-6 degree range. n is equal to the minimum value within the measured 1-degree range. For example, when performing small-cycle angular accuracy calibration measurements for the induction synchronizer in the 0-1 degree range, n = 0; when performing small-cycle angular accuracy calibration measurements for the 1-2 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 that the two-dimensional scanning mechanism enters the uniform speed section during movement, and calculates the distance to the field of view of the photoelectric autocollimator. When the distance reaches the field of view of the photoelectric autocollimator, the ground inspection sends a synchronization mark to the acquisition angle computer to synchronize the measurement initial 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-speed scan command to the control box of the two-dimensional scanning mechanism, and the two-dimensional scanning mechanism starts pointing scanning.

[0129] Step 3.3: After the two-dimensional scanning mechanism reaches a uniform speed, when it reaches the field of view of the photoelectric autocollimator, a ground detection feedback mark 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 also record the position and time of the inductive synchronizer.

[0131] Step 3.5: Control the two-dimensional scanning mechanism to complete the acquisition of the full-field 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 to 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 low-speed and uniform scanning within the field of view of the photoelectric autocollimator.

[0134] Specifically, during 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 for different speeds. The two-dimensional scanning mechanism is required to perform ultra-low and uniform slow scanning in the current test acquisition. The scanning speed of the two-dimensional scanning mechanism is set to 0.003 degrees per second, and the photoelectric autocollimator is tested and acquired at a frequency of 60 Hz for the current scanning process.

[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, that is, 100 Hz, to obtain the movement degree;

[0136] L=1 / 2VT

[0137] V is the current scanning speed, for example: 0.003 degrees per second; T is the acceleration time, for example: acceleration according to 2 beats, that is, 100 Hz, 0.1 seconds; L is the movement degree of the two-dimensional scanning mechanism in the acceleration stage, that is, the angular distance of the two-dimensional scanning mechanism in the acceleration stage, for example: L = 1 / 2*0.003*0.1 = 0.00015 degrees.

[0138] Then convert the movement degrees into arc seconds to facilitate unit unification

[0139] D=L*3600

[0140] D is L converted from degrees to arc seconds, for example: D = 0.00015 * 3600 = 0.54 arc seconds.

[0141] Confirm that the angular distance of the acceleration section is D, and set aside D plus 0.1 arc seconds for the start time of the photoelectric autocollimator dynamic acquisition. After D angles, when the ground detection reaches a uniform speed, a feedback flag is given to the acquisition angle computer to start acquisition. After another 0.1 seconds, it enters the field of view of the photoelectric autocollimator to collect and access data.

[0142] During the dynamic precision 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, in order to ensure the accuracy of the subsequent angle precision calibration measurement, we can also clean the marble platform 4, the bottom of the two-dimensional scanning mechanism 1, the bottom of the multi-tooth indexing table 2, the horizontal adjustment gasket, the photoelectric autocollimator installation tool 3 and the screw plate 7 with alcohol soaked and dust-free cloth during the entire device assembly process. After cleaning, follow the Figure 1The assembly inspection device shown in the figure uses a level and a micrometer to confirm the flatness; at the same time, before the test begins, all test cables are connected to confirm that the equipment is working properly and the photoelectric autocollimator 3 can receive the mirror reflection value of the two-dimensional pointing mechanism 1.

[0144] Through the above steps, we have completed the static and dynamic accuracy calibration of the 2D scanning mechanism 1. Furthermore, during the static accuracy calibration, we completed large-cycle angular accuracy calibration measurements at 5-inch intervals within the angular measurement range (within the ±20-degree range of the induction synchronizer) and small-cycle angular accuracy calibration measurements at 2.5-inch intervals in up to six 1-degree intervals of the induction synchronizer.

Claims

1. A two-dimensional scanning mechanism with large-scale and high-precision angle measurement accuracy detection device, characterized by: It includes a two-dimensional scanning mechanism, a multi-tooth indexing table, a photoelectric autocollimator, a marble platform with a flatness of level 0 or above, an angle acquisition circuit, a motion control box, a screw plate, a level adjustment spacer, a photoelectric autocollimator installation tool, an angle acquisition computer and a ground inspection device; The 2D scanning mechanism and multi-tooth indexing table are placed on a marble platform. The photoelectric autocollimator mounting fixture is installed on the multi-tooth indexing table, and the photoelectric autocollimator is installed on the photoelectric autocollimator mounting fixture. Horizontal adjustment spacers are used to adjust the multi-tooth indexing table and the 2D scanning mechanism to be parallel. This ensures that the photoelectric autocollimator can receive the mirror reflection value of the 2D pointing mechanism. The angle acquisition circuit is connected to the motion control box. Cables are used to connect the motion control box to the ground detection system, the photoelectric autocollimator to the angle acquisition computer, and the ground detection system to the angle acquisition computer. 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″, dynamic angle measurement data acquisition at 60hz, and high-speed acquisition at 1KHZ; The angle acquisition circuit is used to collect the position changes 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 obtain the position information of the angle acquisition circuit and control the motor of the two-dimensional scanning mechanism. The scanning control accuracy is better than 0.2"; The acquisition angle computer is used to connect the angle change value of the photoelectric autocollimator, and the angle change value is stored in the acquisition angle computer; The ground detection is used to send instructions to the motion control box to make the two-dimensional scanning mechanism point to scan; the ground detection is also used to collect the position information of the angle acquisition circuit and the current and motion mode data of the motion control box. Its acquisition frequency supports up to 10Mhz.

2. The device for detecting large-scale and high-precision angle measurement of a two-dimensional scanning mechanism according to claim 1, characterized in that: The thickness of the level adjustment gasket 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 large range, characterized by: The method is carried out using the large-range high-precision angle measurement accuracy detection device of the two-dimensional scanning mechanism according to claim 1 or 2, specifically comprising the following steps: Step 1: Use the horizontal adjustment spacer to adjust the verticality of the photoelectric autocollimator and 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: complete the angle calibration to determine the angle measurement range at 5′ intervals; Step 2.2: Perform small-cycle angle accuracy calibration measurement: Select up to six 1-degree intervals of the inductor and perform angle calibration for each 1-degree interval. Use 24 measurement points at 2.5-inch intervals to complete the 1-degree angle calibration of the inductor. Step 3: Perform dynamic accuracy calibration, including the following steps: Step 3.

1. The ground inspection system calculates the distance the two-dimensional scanning mechanism enters the uniform speed section during movement, and calculates the distance to the field of view of the photoelectric autocollimator. When the distance reaches the field of view of the photoelectric autocollimator, the ground inspection system sends a synchronization flag to the acquisition angle computer, synchronizing the measurement and calibration initial times of the photoelectric autocollimator and the ground inspection system, and aligning 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 starts pointing scanning; Step 3.3: After the two-dimensional scanning mechanism reaches a uniform speed, when it reaches the field of view of the photoelectric autocollimator, a 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 also record the position and time of the inductive synchronizer; Step 3.5: Control the two-dimensional scanning mechanism to complete the acquisition of the full-field 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 to 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 large-scale, 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 pitch value error adjustment method within the ±20 degree angle measurement range is as follows: Send a command from the ground inspection station to point to -20 degrees. Use the multi-tooth indexing table to move to -20 degrees and record the current pitch value. Then point to 20 degrees and record the current pitch value. Compare the pitch value error within the ±20 degree range. Use the horizontal adjustment shims to make adjustments. Repeat the pointing until the pitch error within the ±20 degree range is adjusted to less than 1".

5. The method for detecting large-scale, 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, and the specific method for calibrating the large-cycle angle accuracy of the induction synchronizer measuring 40 degrees is as follows: Step 2.1.

1. Point the 2D scanning mechanism to -20 degrees, move the multi-tooth indexing table to +20 degrees, adjust the pitch error of the center of the spot field of view to within ±1 arc second, and determine it as the starting point. The current starting point photoelectric autocollimator is recalibrated to 0°0′0″. Record the current data values ​​of the current induction synchronizer and photoelectric autocollimator; Step 2.1.2, then rotate the 2D scanning mechanism at 5' intervals and simultaneously rotate the multi-scale indexing table in the opposite direction. The 2D scanning mechanism and the multi-scale indexing table rotate 5' each time, and test and record them in turn. The data values ​​of the induction synchronizer and the photoelectric autocollimator total 480 groups; a test is performed every 5', among which, is the difference between the two test data before and after the photoelectric autocollimator; The value is calculated as follows: After the multi-tooth indexing table completes its rotation, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data A. N is the number of acquisitions, ai is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator; After the multi-tooth indexing table completes its rotation again, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data B. The data is collected for 5 seconds at rest: N is the number of acquisitions, bi is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator; The difference between the photoelectric autocollimator data A and the photoelectric autocollimator data B is recorded as Step 2.1.3: Measure steps 2.1.1 to 2.1.2 three times in total according to the repeatability requirements.

6. The method for detecting large-scale, 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 1-degree angle of the induction synchronizer is as follows: Step 2.2.

1. Point the 2D scanning mechanism to n degrees, where n is greater than or equal to 0. Move the multi-tooth indexing stage to n degrees, align the optical axis, and obtain the current data from the photoelectric autocollimator. Adjust the center of the spot field of view to within ±1 arc second, and determine it as the starting point. Recalibrate the photoelectric autocollimator at the current starting point to 0°0′0, and record the current data values ​​of the induction synchronizer and the photoelectric autocollimator. Step 2.2.2: Rotate the 2D scanning mechanism at 2.5″ intervals and simultaneously rotate the multi-scale indexing table in the opposite direction. The 2D scanning mechanism and multi-scale indexing table rotate 2.5″ each time. Test and record the results in 2.5″ intervals. The data values ​​of the induction synchronizer and the photoelectric autocollimator total 24 sets of data; a test is performed every 2.5″, among which, The difference between the two data of the photoelectric autocollimator during the two tests; The value is calculated as follows: After the multi-tooth indexing table completes its rotation, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data A. N is the number of acquisitions, ai is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator; After the multi-tooth indexing table completes its rotation again, it is locked and waits for 5 seconds to stabilize. Then, the photoelectric autocollimator data is collected for 1 second and averaged to obtain the photoelectric autocollimator data B. The data is collected for 5 seconds at rest: N is the number of acquisitions, bi is the acquired data, and the average value is collected and calculated by the acquisition computer in the photoelectric autocollimator; The difference between the photoelectric autocollimator data A and the photoelectric autocollimator data B is recorded as Step 2.2.3: Measure steps 2.2.1 to 2.2.2 a total of three times according to the repeatability requirements.

7. The method for detecting large-scale, high-precision angle measurement accuracy of a two-dimensional scanning mechanism according to claim 6, characterized in that: 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. The current test acquisition requires the two-dimensional scanning mechanism to scan at an ultra-low uniform speed. The scanning speed of the two-dimensional scanning mechanism is set to 0.003 degrees per second. The photoelectric autocollimator tests and acquires the current scanning process at a frequency of 60 Hz. 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, that is, 100 Hz, to obtain the movement degree: L=1 / 2VT V is the current scanning speed of the two-dimensional scanning mechanism, in degrees per second; T is the acceleration time of the two-dimensional scanning mechanism, in seconds; L is the movement degree of the two-dimensional scanning mechanism in the acceleration stage, that is, the angular distance moved by the two-dimensional scanning mechanism in the acceleration stage, in degrees; Then convert the movement degrees into arc seconds to facilitate unit unification: D=L*3600 D is the angular distance moved by the acceleration section of the two-dimensional scanning mechanism, in arc seconds; Confirm that the angular distance of the acceleration section is D, and set aside D plus 0.1 arc seconds for the start time of the photoelectric autocollimator dynamic acquisition. After D angles, when the ground detection reaches a uniform speed, a feedback flag is given to the acquisition angle computer to start acquisition. After another 0.1 seconds, it enters the field of view of the photoelectric autocollimator to collect and access data.

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