Non-contact detection system and method for surface shape precision of Wolter-I type reflector barrel

Abstract

The invention discloses a Wolter-I type reflector barrel surface shape precision non-contact detection system. The system comprises a base support, a damping platform, a linear displacement system, a vertical measuring arm, a laser displacement measuring head, an air floating rotary table, a tray and a control and data acquisition platform. The invention also discloses a Wolter-I type reflector barrel surface shape precision non-contact detection method, which comprises the following steps: placing a reflector barrel on the tray capable of rotating together with the air floating turntable, and carrying out horizontal and central adjustment on the reflector by using the tray; the laser displacement measuring head sequentially obtains coordinate values of all measuring points on the inner wall of the reflector barrel according to the planned path; and the control and data acquisition platform processes the coordinate value of each measuring point and then gives the surface shape precision of the reflector barrel. The method can complete the surface shape error detection of the reflector cone, provides feedback and guidance for the processing of the reflector cone, provides input and basis for the adjustment of an optical system, and plays an important role in the development of the reflector cone.

Description

Technical Field

[0001] This invention belongs to the field of space optics technology and relates to a non-contact detection system and method for the surface shape accuracy of a Wolter-I type reflector tube. Background Technology

[0002] Grazing-incidence X-ray focusing mirrors are core components of X-ray astronomical observation payloads, used to converge and collect X-rays from the universe. The Wolter-I type multi-layer nested mirror is currently the most commonly used type of grazing-incidence X-ray focusing mirror. It reflects grazing-incidence X-rays to the focal plane, exhibiting high focusing efficiency and strong imaging detection capabilities, and has received widespread attention and research internationally. Each layer of the Wolter-I type mirror contains a cylindrical parabolic primary mirror and a hyperboloid secondary mirror. Traditional methods cannot detect the surface shape of the internal reflecting surfaces. The mirrors are thin-walled structures, highly susceptible to gravitational deformation, requiring surface shape detection in a vertical position. Furthermore, the mirror surfaces have high precision, with roughness on the sub-nanometer scale and surface shape on the sub-micrometer scale; contact measurements easily scratch the surface, necessitating non-contact measurement methods. Therefore, the need for non-contact surface shape detection of this type of mirror is urgent. Internationally, vertical long-range profilometers (VSLTP) are used to detect the surface shape of Wolter-I type mirrors, but these methods are complex, inefficient, and costly. Research and manufacturing of X-ray mirrors in China are still in their infancy. High-precision detection of mirror surface shape can provide feedback for mirror processing, which is particularly important for improving the manufacturing level of mirrors. Summary of the Invention

[0003] The purpose of this invention is to overcome the aforementioned shortcomings and provide a non-contact inspection system and method for the surface shape accuracy of Wolter-I type reflector tubes, solving the technical problems of low measurement efficiency and high cost of existing Wolter-I type reflector tubes. This invention can complete the surface shape error detection of reflector tubes, providing feedback and guidance for reflector tube processing, and providing input and basis for optical system assembly and adjustment, playing an important role in the development of reflector tubes. This invention has the advantages of wide applicability, high accuracy, and high measurement efficiency.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention discloses a non-contact detection system for the surface shape accuracy of a Wolter-I type reflector barrel, comprising: a base support, inflatable shock-absorbing pads, a shock-absorbing platform, a Z-axis linear displacement system, an X-axis linear displacement system, a vertical measuring arm, a laser displacement probe, an air-bearing turntable, a tray, a compressed air supply system, and a control and data acquisition platform. The shock-absorbing platform includes a marble platform and marble columns. This invention also discloses a non-contact detection method for the surface shape accuracy of a Wolter-I type reflector barrel, comprising: installation and leveling of the reflector barrel; planning of the detection path and number of detection points; detection, viewing, and saving of surface shape data; processing the detection data to obtain the RMS value for evaluating surface shape accuracy, thus completing the surface shape accuracy detection of the reflector barrel. This invention can complete the surface shape error detection of reflector barrels, and the detection data can be exported for actual surface fitting and optical performance simulation, thereby providing feedback and guidance for reflector barrel processing and providing input and basis for optical system assembly and adjustment, playing an important role in the development of reflector barrels. This invention has the advantages of wide applicability, high accuracy, and high measurement efficiency.

[0006] Specifically, the solution of this invention is as follows:

[0007] A Wolter-I type non-contact inspection system for the surface shape accuracy of a reflector tube includes a base support, a shock-absorbing platform, a linear displacement system, a vertical measuring arm, a laser displacement probe, an air-bearing turntable, a tray, and a control and data acquisition platform;

[0008] The base support is placed on a level ground, and the shock-absorbing platform is installed above the base support;

[0009] An air-bearing turntable is mounted on a vibration-damping platform, and a tray is mounted on the air-bearing turntable via a ball joint. The reflector tube under test is mounted on a chuck. The air-bearing turntable drives the reflector tube under test to rotate, keeping the optical axis of the reflector tube vertical, so that the laser displacement probe moves in a circular motion relative to the reflector tube. A linear displacement system is mounted on the vibration-damping platform, with the upper end of a vertical measuring arm mounted on the linear displacement system and the lower end of the vertical measuring arm fixed to the laser displacement probe. The linear displacement system drives the laser displacement probe to move in a straight line along the generatrix direction relative to the reflector tube through the vertical measuring arm, scanning each measuring point on the inner wall of the reflector tube and obtaining the coordinate values ​​of each measuring point.

[0010] The control and data acquisition platform is used to control the linear displacement system and the air-bearing turntable, and to process the coordinate values ​​of each measuring point to give the surface accuracy of the measured reflector tube.

[0011] Furthermore, the shock-absorbing platform includes a marble water platform and marble columns;

[0012] The marble water platform is placed on the base support through inflatable shock-absorbing pads, and the upper surface of the marble water platform is horizontal; the air-floating turntable is installed on the marble water platform.

[0013] The marble column is vertically installed on one side of the marble water platform, and the linear displacement system is installed on the side of the marble column.

[0014] Furthermore, the tray has horizontal and center adjustment functions, with a horizontal adjustment accuracy of 10′ and a center adjustment accuracy of 0.2mm;

[0015] The tray includes a chuck body and micro heads; the chuck body has a disc-shaped structure, and the lower end face of the chuck body is supported by three micro heads evenly distributed in the circumferential direction. By adjusting the three micro heads to make their extension lengths equal, the horizontal adjustment of the reflector tube is achieved; the upper surface of the chuck body has four micro heads evenly distributed in the circumference. By adjusting the four micro heads to make their extension lengths equal, so that the four micro heads are in just contact with the outer surface of the reflector tube, the center adjustment of the reflector tube is achieved.

[0016] Furthermore, the linear displacement system includes a Z-axis linear displacement system and an X-axis linear displacement system;

[0017] The fixed part of the Z-axis linear displacement system is installed on the side of the marble column, the fixed part of the X-axis linear displacement system is installed on the moving part of the Z-axis linear displacement system, the upper end of the vertical measuring arm is installed on the moving part of the X-axis linear displacement system, and the laser displacement probe is installed on the lower end of the vertical measuring arm. The Z-axis linear displacement system and the X-axis linear displacement system drive the laser displacement probe to move in the vertical and horizontal directions respectively to complete the scanning of the measuring point.

[0018] Furthermore, the Z-axis linear displacement system and the X-axis linear displacement system are configured with linear grating rulers to form a closed-loop displacement system with a repeatability accuracy better than 0.5μm. The grating ruler is installed in the fixed part of the displacement system, and the reading head is installed in the moving part of the displacement system. The grating ruler of the Z-axis linear displacement system has a measuring stroke of 400mm, and the grating ruler of the X-axis linear displacement system has a measuring stroke of 220mm, which is suitable for the surface shape detection of reflector tubes with diameter × height ≤ Φ400mm × 350mm. The position detection signal of the linear grating ruler is fed back to the control and data acquisition platform for the position control of the laser displacement probe.

[0019] Furthermore, the end runout and radial runout of the air-bearing turntable are both better than 0.1 μm, and the angular accuracy is 0.2".

[0020] The laser displacement probe is a non-contact optical probe with a resolution better than 30nm, a measurement accuracy of 0.75μm, and a diameter of 20mm. To avoid interference between the laser displacement probe and the reflector tube, the diameter of the reflector tube is ≥120mm.

[0021] A non-contact method for detecting the surface shape accuracy of a Wolter-I type reflector barrel, implemented using the aforementioned non-contact detection system for the surface shape accuracy of a Wolter-I type reflector barrel, includes:

[0022] S1 activates compressed air, allowing the air-float turntable to rotate freely;

[0023] S2 mounts the reflector tube to be tested onto the air-bearing turntable via a tray, with the large-diameter end of the reflector tube facing upwards;

[0024] S3 starts the control and data acquisition platform, using the tray and the control and data acquisition platform to complete the horizontal and center adjustments of the reflector tube; controls the laser displacement probe to move to the upper end of the inner wall of the reflector tube under test, and records the Z-axis coordinate of the laser displacement probe as H; then controls the laser displacement probe to move to the lower end of the inner wall of the reflector tube under test, and records the Z-axis coordinate of the laser displacement probe as h; the Z-axis is along the vertical direction;

[0025] S4 generates a planned path based on H and h, and the control and data acquisition platform controls the laser displacement probe to obtain the coordinate values ​​of each measuring point on the inner wall of the reflector tube in sequence according to the planned path.

[0026] The S5 control and data acquisition platform processes the coordinate values ​​of the inner wall of the reflector tube to provide the surface accuracy of the measured reflector tube.

[0027] Furthermore, the pallet includes a chuck body and micro heads; the chuck body has a disc-shaped structure, and the lower end face of the chuck body is supported by three micro heads evenly distributed in the circumferential direction, while the upper surface of the chuck body has four micro heads evenly distributed in the circumference.

[0028] In step S3, the method for adjusting the horizontal and center of the reflector tube includes coarse horizontal and coarse center adjustment of the reflector tube, or, after coarse horizontal and coarse center adjustment of the reflector tube, fine horizontal and fine center adjustment are performed.

[0029] The methods for horizontal coarse adjustment and center coarse adjustment include:

[0030] By adjusting the three micrometer heads on the lower end face of the chuck body, the angle between the upper surface of the tray and the horizontal plane is less than 10′, thus achieving coarse horizontal adjustment of the reflector tube. By adjusting the four micrometer heads on the upper surface of the chuck body and adjusting the position of the reflector tube, the four micrometer heads are made to just contact the outer surface of the reflector tube. Then, the micrometer heads are moved back half a turn to avoid applying external force to the reflector tube, so that the distance between the center of the reflector tube and the rotation center of the air-bearing turntable is less than 0.2mm, thus achieving coarse center adjustment of the reflector tube.

[0031] The methods for horizontal and center fine adjustment include: the control and data acquisition platform controls the laser displacement probe to obtain the coordinate values ​​of each measuring point on the inner wall of the reflector tube, and adjusts the three micrometer heads on the lower end face of the chuck body and the four micrometer heads on the upper surface of the chuck body according to the coordinate values ​​to achieve horizontal and center fine adjustment of the reflector tube.

[0032] In summary, this invention adjusts the three micrometer heads on the lower surface of the tray to make the angle between the upper surface of the tray and the horizontal plane <10′, and adjusts the four micrometer heads on the upper surface of the tray to make the distance between the center of the reflector tube and the rotation center of the air-bearing turntable less than 0.2mm. Coarse adjustment is based on the scale of the micrometer heads, and fine adjustment is based on the measured data of the inner surface of the reflector.

[0033] Furthermore, in step S4, the path planning includes: obtaining the coordinate values ​​of each measuring point on the first busbar from bottom to top, then rotating the reflector tube by a predetermined angle to obtain the coordinate values ​​of each measuring point on the next busbar, until the measurement of the entire inner surface of the reflector tube is completed; when obtaining the coordinate values ​​of each measuring point on each busbar from bottom to top, the distance between the laser displacement probe and the inner surface of the reflector tube remains unchanged.

[0034] Configure z in the control and data acquisition platform i z and n are used as path planning parameters, where z i The z-axis coordinates are the distance from the lowest measuring point to the highest measuring point. i = h + (i-1)·d, i = 1, 2, 3, ..., m, where i represents the i-th measurement point and m is the total number of measurement points on the same generatrix. d is the step size for measuring along the generatrix; n is the number of generatrixes measured uniformly along the circumference, n≥4.

[0035] Furthermore, in step S5, the method for obtaining the surface shape accuracy of the tested reflector tube includes:

[0036] Suppose the measured coordinates of the inner wall of the reflecting mirror tube are and the corresponding coordinates of the ideal surface shape of the reflecting mirror tube are (x... i ',y i ',z i ), component z i The Z-axis position of the measurement point in the measurement coordinate system is represented by the value. Since the ideal surface and the actual surface take the same value, the surface shape error value at each measurement point is...

[0037] Root mean square value of surface accuracy

[0038] Where k is the total number of measurement points.

[0039] Compared with the prior art, the present invention has at least one of the following advantages:

[0040] (1) The non-contact detection system and method proposed in this invention can quickly and accurately calibrate the surface shape accuracy of reflective tubes of different diameters, and provide feedback and guidance for the processing technology of reflective tubes and the assembly and integration of optical systems.

[0041] (2) The present invention can ensure the relative positional accuracy between the reflector tube surface and the laser displacement probe by means of components such as tray and air-floating platform, which can effectively improve the measurement accuracy;

[0042] (3) The present invention realizes non-contact detection of surface shape accuracy in the vertically placed state of the reflector tube, which can reduce the influence of gravity deformation on surface shape accuracy. Non-contact detection will not damage the reflector tube, thus accurately detecting the actual surface shape accuracy of the reflector tube.

[0043] (4) This invention provides a method for planning measurement paths, thereby achieving comprehensive and effective detection and characterization of the measured surface, improving measurement efficiency and the validity of measurement data;

[0044] (5) This invention provides a method for processing and evaluating measurement data, which can realize rapid and direct evaluation of surface accuracy and improve measurement efficiency;

[0045] (6) The measurement data obtained by this invention can be further used for actual surface fitting and optical simulation to achieve a comprehensive evaluation from geometric accuracy to optical performance, which is of guiding significance for subsequent mirror tube assembly and adjustment. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the non-contact surface shape accuracy detection system of the present invention;

[0047] Figure 2 This is a schematic diagram of the tray including the self-aligning and leveling mechanism of the present invention;

[0048] Figure 3 This is a schematic diagram of the measurement path planning for the present invention;

[0049] Figure 4 This is a schematic diagram of the measurement data of the present invention;

[0050] Among them, 1-base support, 2-inflatable shock-absorbing pad, 31-marble water platform, 32-marble column, 4-Z-axis linear displacement system, 5-X-axis linear displacement system, 6-vertical measuring arm, 7-laser displacement probe, 8-air-float turntable, 9-tray, 91-tray body, 92-micrometer head, 10-compressed air supply system, 11-control and data acquisition platform. Detailed Implementation

[0051] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0052] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0053] This invention provides a non-contact inspection system and method for the surface shape accuracy of a Wolter-I type reflector. The system and method employ a high-precision rotary table and a nanometer-precision non-contact probe. Before inspection, the reflector can be horizontally and centrally adjusted. Considering the reflector's thin-walled and easily deformable structure, a tray is used to support it. Three micrometer probes are evenly distributed on the circumference of the lower end face of the tray, allowing for coarse horizontal adjustment. Four micrometer probes are evenly distributed on the circumference of the upper end face of the tray. These probes can be steplessly adjusted along a groove in the radial direction of the tray according to a scale indication to accommodate reflectors of different diameters. By adjusting the position of the reflector on the tray and the extension length of the four micrometer probes, the extension length of each probe is made equal to the extension length when in contact with the outer surface of the reflector. Then, the micrometer probes are retracted half a turn to avoid applying external force to the reflector, achieving coarse central adjustment. Fine adjustment of the horizontal and central aspects is carried out in conjunction with the inspection data of the inner surface of the reflector.

[0054] This system and method enables rapid non-contact inspection of the generatrix on the inner surface of a Wolter-I type reflector. The inner surface of the cylindrical reflector is divided into a parabolic surface and a hyperboloid, with the radius gradually increasing from the hyperboloid end (small diameter end) to the parabolic end (large diameter end). When measuring the generatrix, if the probe only moves along the optical axis (Z-axis), the small and large ends cannot simultaneously be within the probe's measurement range. Therefore, an adaptive probe movement method is adopted, whereby the probe moves along the optical axis while simultaneously moving radially along the reflector, ensuring that the inner surface of the reflector is always within the probe's measurement range and guaranteeing continuous measurability of the entire generatrix. Simultaneously, non-contact inspection of the circumferential surface shape can also be performed, and the inspection data can be displayed and exported for subsequent actual surface fitting and optical performance simulation. This provides feedback and guidance for reflector manufacturing and input and basis for optical system assembly and adjustment.

[0055] A Wolter-I type non-contact detection system for the surface shape accuracy of a reflector tube specifically includes: a base support, an inflatable shock-absorbing pad, a shock-absorbing platform, a Z-axis linear displacement system, an X-axis linear displacement system, a vertical measuring arm, a laser displacement probe, an air-bearing turntable, a tray, a compressed air supply system, and a control and data acquisition platform. The shock-absorbing platform includes a marble platform and marble columns.

[0056] The base support is placed on a horizontal surface, and the marble platform is placed on the base support using inflatable shock-absorbing pads. The Z-axis linear displacement system is installed on the side of the marble column, with its movement direction being vertical. The X-axis linear displacement system is installed on the moving part of the Z-axis linear displacement system, with its movement direction being horizontal. The vertical measuring arm is installed at the end of the X-axis linear displacement system, and a laser displacement probe is fixed to the end of the vertical measuring arm. The air-bearing turntable is fixed on the marble platform, and the tray is fixed on the air-bearing turntable for mounting the reflector tube under test and keeping the optical axis of the reflector tube vertical. The compressed air supply system supplies compressed air to the air-bearing turntable. The control and data acquisition platform realizes motion control, measurement control, data acquisition and processing of the detection system.

[0057] Furthermore, the Z-axis linear displacement system and the X-axis linear displacement system are precision moving stages. By configuring linear grating rulers for the Z-axis linear displacement system and the X-axis linear displacement system, a closed-loop displacement system is formed, with a repeatability accuracy better than 0.5μm. The grating ruler is installed in the fixed part of the displacement system, and the reading head is installed in the moving part of the displacement system. The grating ruler measuring stroke of the Z-axis linear displacement system (4) is 400mm, and the grating ruler measuring stroke of the X-axis linear displacement system (5) is 220mm, which is suitable for the surface shape detection of a reflector tube with a diameter × height ≤ Φ400mm × 350mm.

[0058] Furthermore, the air-bearing turntable is an ultra-high precision air-bearing turntable, with end runout and radial runout both better than 0.1μm, angular accuracy of 0.2", and a table size of 300mm.

[0059] Furthermore, the tray features both horizontal and center adjustment functions, achieving a horizontal adjustment accuracy of 10′ and a center adjustment accuracy of 0.2mm for the reflector tube. Specifically, the tray's center is supported by a ball joint, and its lower end is supported by three evenly distributed micro-heads along the circumference. The micro-heads have ball tips that make point contact with the lower end of the tray. By adjusting the three micro-heads to make their extension lengths equal, coarse horizontal adjustment of the reflector is achieved. Four micro-heads are evenly distributed around the circumference of the tray's upper surface. The radial position of the micro-heads can be steplessly adjusted along a groove to accommodate different reflector diameters. By adjusting the four micro-heads to make their extension lengths equal and adjusting the position of the reflector so that all four micro-heads are in just contact with the outer surface of the reflector, and then retracting the micro-heads by half a turn to avoid applying external force to the reflector, coarse center adjustment of the reflector is achieved. Finally, based on the measured data of the inner surface of the reflector, fine adjustment of the micro-heads is performed to complete the center and horizontal adjustment of the reflector.

[0060] Furthermore, the laser displacement probe is a non-contact optical probe with a resolution better than 30nm, a measurement accuracy of 0.75μm, a maximum diameter of 20mm, and can be adapted to reflective tubes with an inner diameter of not less than 120mm.

[0061] Furthermore, a measurement coordinate system is established with the intersection point O of the air-bearing turntable's rotation axis and the upper surface of the tray as the origin, the horizontal direction of the linear displacement system pointing to the X-axis as the X-axis, and the vertical upward direction as the Z-axis.

[0062] A non-contact method for detecting the surface shape accuracy of a Wolter-I type reflector barrel, implemented using the aforementioned non-contact detection system for the surface shape accuracy of a Wolter-I type reflector barrel, includes:

[0063] S1 starts the compressed air supply system and opens the air valve, allowing the air-floating turntable to rotate freely;

[0064] S2 Adjust the upper surface of the tray to a horizontal position, install the reflector tube to be tested onto the tray, and adjust the center of the reflector tube;

[0065] S3 starts the control and data acquisition platform, controls the laser displacement probe to move to the upper end of the inner wall of the reflector tube under test, records the Z-axis coordinate of the probe as H, and then controls the laser displacement probe to move to the lower end of the inner wall of the reflector tube under test, records the Z-axis coordinate of the probe as h;

[0066] S4 plans the measurement path of the laser displacement probe based on the size of the reflector tube being measured;

[0067] S5 initiates the measurement program. The detection system controls the Z-axis linear displacement system, X-axis linear displacement system, and air-bearing turntable movement according to the planned path. First, the probe is moved to the lowest measuring point of the first generatrix to begin measurement. After measuring the first point, the probe moves upward along the Z-axis while simultaneously moving along the X-axis to the surface being measured, ensuring that the surface being measured remains within the probe's range. This process is repeated for each measuring point on the first generatrix. Then, the probe moves away from the surface being measured along the X-axis and back to its lowest position along the Z-axis. The turntable rotates by an angle Δθ to begin measuring the next generatrix, and so on, until the entire inner surface is measured. This yields the coordinates (x, y, y) of each point on the inner surface of the measured reflector tube in the measurement coordinate system. i y i , z i The measurement data is saved in real time.

[0068] S6 combines the ideal surface shape of the reflector tube under test, processes the test data, calculates the RMS value of the reflector tube surface shape accuracy, and completes the test of the reflector tube surface shape accuracy.

[0069] Furthermore, in step S1, the horizontal adjustment makes the angle between the upper surface of the tray and the horizontal plane <10′, and the center adjustment makes the distance between the center of the reflector tube and the rotation center of the air-bearing turntable less than 0.2mm.

[0070] Furthermore, in step S4, the step size for measurement along the busbar is set to d, then the Z-axis coordinate value from the lowest measuring point to the highest measuring point is z.i =h + (i-1)·d, i = 1, 2, 3, ..., m, where i is the number of measurement points, then If n generatrices are uniformly measured along the circumference, then the included angle between adjacent generatrices is . The total number of measuring points k = m·n; In the control and data acquisition platform, set z... i and n are used as measurement path parameters;

[0071] Furthermore, in step S6, it is assumed that the coordinate values ​​of the ideal surface shape of the reflecting mirror tube corresponding to the measurement path are (x... i ',y i ',z i If the surface shape error value at each measuring point is..., then the surface shape error value at each measuring point is... The root mean square value of the surface accuracy

[0072] Example:

[0073] This invention proposes a non-contact method for detecting the surface accuracy of a Wolter-I type reflector barrel based on a laser displacement probe. The method utilizes an air-bearing turntable to support the reflector barrel, and drives the laser displacement probe on the vertical measuring arm along a pre-planned measurement path via Z-axis and X-axis linear displacement systems to detect the surface accuracy of the inner surface of the reflector barrel. The actual surface data is obtained, and after relevant processing and calculation, the RMS value characterizing the surface accuracy of the reflector barrel is obtained. This method has advantages such as wide applicability, high accuracy, and high measurement efficiency. It can provide feedback and guidance for reflector barrel manufacturing and input and basis for optical system assembly and adjustment.

[0074] like Figure 1 This invention provides a Wolter-I type non-contact inspection system for the surface shape accuracy of a reflector tube, comprising: a base support 1, an inflatable shock-absorbing pad 2, a marble platform 31, a marble column 32, a Z-axis linear displacement system 4, an X-axis linear displacement system 5, a vertical measuring arm 6, a laser displacement probe 7, an air-bearing turntable 8, a tray 9, a compressed air supply system 10, and a control and data acquisition platform 11. The non-contact inspection system for surface shape accuracy is installed according to the following steps:

[0075] Step 1: Place the base bracket 1 on a horizontal surface, and place the marble platform 31 on the base bracket 1 using inflatable shock-absorbing pads;

[0076] Step 2: Install the fixed part of the Z-axis linear displacement system 4 on the side of the marble column 32, with the moving part moving in the vertical direction; install the fixed part of the X-axis linear displacement system 5 on the moving part of the Z-axis linear displacement system 4, with the moving part moving in the horizontal direction; install the vertical measuring arm 6 at the end of the X-axis linear displacement system 5, and fix the laser displacement probe 7 at the end of the vertical measuring arm 6; the linearity of the Z-axis linear displacement system 4 and the X-axis linear displacement system 5 is ≤0.01mm / mm;

[0077] Step 3: Fix the air-bearing turntable 8 onto the marble platform 31. Then, install the tray body 91 onto the air-bearing turntable 8 via a ball joint to support the reflector tube under test and keep the optical axis of the reflector tube vertical. Install the micrometer head 92 onto the chuck body 91 for centering and leveling the reflector tube under test. Figure 2 Step 4: Connect the compressed air supply system 10 to the air-float turntable 8 via an air pipe, thereby supplying compressed air to the air-float turntable 8.

[0078] Step 5: Connect the computer of the control and data acquisition platform 10 to the non-contact detection system to realize motion control, measurement control, data acquisition and processing of the detection system.

[0079] The present invention also provides a non-contact method for detecting the surface shape accuracy of a mirror barrel using the aforementioned Wolter-I type mirror barrel surface shape accuracy non-contact detection system, comprising:

[0080] Step 1: Start the compressed air supply system and open the air valve to allow the air-floating turntable to rotate freely;

[0081] Step 2: Prepare the Wolter-I type reflector tube to be tested; clean the reflector tube and related tooling equipment with alcohol; place the reflector tube to be tested on the tray with the large diameter end of the reflector tube facing upwards.

[0082] Step 3: Start the control and data acquisition platform, adjust the upper surface of the tray to a horizontal position, and center the reflector tube; control the laser displacement probe to move to the upper end of the inner wall of the reflector tube being measured, such as... Figure 3 Record the Z-axis coordinate of the probe as H, and then control the laser displacement probe to move to the lower end of the inner wall of the reflector tube being tested, and record the Z-axis coordinate of the probe as h.

[0083] Step 4: Plan the measurement path of the laser displacement probe according to the size of the reflector tube being measured;

[0084] Step 5: Start the measurement program. The detection system controls the Z-axis linear displacement system, X-axis linear displacement system, and air-bearing turntable to move according to the planned path, sequentially completing the measurement of each measuring point and obtaining the coordinate values ​​(x, y, y) of each point on the inner surface of the tested reflector tube in the measurement coordinate system. i y i , z i The measurement data is saved in real time.

[0085] Step 6: Combine the ideal surface shape of the mirror tube under test, process the test data, calculate the RMS value of the surface shape accuracy of the mirror tube, and complete the test of the surface shape accuracy of the mirror tube.

[0086] Furthermore, in step three, the horizontal adjustment ensures that the angle between the upper surface of the tray and the horizontal plane is less than 10′, and the center adjustment ensures that the distance between the center of the reflector tube and the rotation center of the air-bearing turntable is less than 0.2 mm; Figure 2 As shown, step three specifically includes: placing a level on the upper surface of the tray, adjusting the three micrometer heads evenly distributed around the circumference of the lower surface of the tray to make their extension lengths equal, thereby achieving coarse horizontal adjustment of the reflector tube; adjusting the four micrometer heads evenly distributed around the circumference of the upper surface of the tray to make their extension lengths equal, and adjusting the position of the reflector tube, thereby achieving coarse centering adjustment of the reflector tube; finally, based on the measured data of the inner surface of the reflector tube, fine adjustment is performed on the micrometer heads to complete the centering and horizontal adjustment of the reflector tube, so that the angle between the upper surface of the tray and the horizontal plane is <10′, and the centering adjustment makes the distance between the center of the reflector tube and the rotation center of the air-bearing turntable less than 0.2mm.

[0087] Furthermore, in step four, if the step size for the measurement along the busbar is set to d, then the Z-axis coordinate value from the lowest measuring point to the highest measuring point is z. i =h + (i-1)·d, i = 1, 2, 3, ..., m, where i is the number of measurement points, then If n generatrices are uniformly measured along the circumference, then the included angle between adjacent generatrices is . The total number of measuring points k = m·n; In the control and data acquisition platform, set z... i and n are used as measurement path parameters;

[0088] Furthermore, in step six, the measurement program is started to sequentially obtain the measurement data (x) on each busbar. i y i , z i ),like Figure 4 As shown; assuming the coordinates of the ideal surface shape of the reflecting mirror tube corresponding to the measurement path are (x... i ',y i ',z i If the surface shape error value at each measuring point is..., then the surface shape error value at each measuring point is... The root mean square value of the surface accuracy

[0089] In summary, the technical solution of this invention includes starting the compressed air supply system, installing the reflector tube under test, aligning and leveling the reflector tube under test, starting the control and data acquisition platform, determining the highest and lowest measurement positions, planning the measurement path, starting the measurement program, completing data measurement and storage, processing and evaluating the measurement data, obtaining the RMS value of the surface shape accuracy of the inner surface of the reflector tube, and completing the inspection. This invention has a wide range of applications, high accuracy, and high measurement efficiency.

[0090] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0091] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A non-contact inspection system for the surface shape accuracy of a Wolter-I type reflective mirror barrel, characterized in that, It includes a base support (1), a shock-absorbing platform, a linear displacement system, a vertical measuring arm (6), a laser displacement probe (7), an air-bearing turntable (8), a tray (9), and a control and data acquisition platform (11); The base bracket (1) is placed on a horizontal ground, and the shock-absorbing platform is installed above the base bracket (1); An air-bearing turntable (8) is installed on a vibration-damping platform. A tray (9) is installed on the air-bearing turntable (8) via a ball joint. The reflector tube under test is installed on a chuck (9). The air-bearing turntable (8) drives the reflector tube under test to rotate. The optical axis of the reflector tube under test remains vertical, so that the laser displacement probe (7) moves in a circular motion relative to the reflector tube. A linear displacement system is installed on a vibration-damping platform. The upper end of the vertical measuring arm (6) is installed on the linear displacement system. The lower end of the vertical measuring arm (6) is fixed to the laser displacement probe (7). The linear displacement system drives the laser displacement probe (7) to move in a straight line along the generatrix direction relative to the reflector tube through the vertical measuring arm (6). The system scans each measuring point on the inner wall of the reflector tube and obtains the coordinate values ​​of each measuring point. The control and data acquisition platform (11) is used to control the linear displacement system and the air-bearing turntable (8) and process the coordinate values ​​of each measuring point to give the surface accuracy of the measured reflector tube.

2. The Wolter-I type reflective mirror tube surface shape accuracy non-contact detection system according to claim 1, characterized in that, The shock-absorbing platform includes a marble water platform (31) and marble columns (32); The marble water platform (31) is placed on the base bracket (1) by an inflatable shock-absorbing pad (2), and the upper surface of the marble water platform (31) is horizontal; the air-floating turntable (8) is installed on the marble water platform (31); The marble column (32) is vertically installed on one side of the marble water platform (31), and the linear displacement system is installed on the side of the marble column (32).

3. The Wolter-I type reflective mirror tube surface shape accuracy non-contact detection system according to claim 1, characterized in that, The tray (9) has horizontal adjustment and center adjustment functions, with a horizontal adjustment accuracy of 10′ and a center adjustment accuracy of 0.2mm; The tray (9) includes a chuck body (91) and micro heads (92); the chuck body (91) is a disc-shaped structure, and the lower end face of the chuck body (91) is supported by three micro heads evenly distributed in the circumferential direction. By adjusting the three micro heads to make their extension length equal, the horizontal adjustment of the reflector tube is realized; four micro heads (92) are evenly distributed in the circumference of the upper surface of the chuck body (91). By adjusting the four micro heads to make their extension length equal, the four micro heads are in just contact with the outer surface of the reflector tube, thus realizing the center adjustment of the reflector tube.

4. The Wolter-I type reflective mirror tube surface shape accuracy non-contact detection system according to claim 2, characterized in that, The linear displacement system includes a Z-axis linear displacement system (4) and an X-axis linear displacement system (5); The fixed part of the Z-axis linear displacement system (4) is installed on the side of the marble column (32), the fixed part of the X-axis linear displacement system (5) is installed on the moving part of the Z-axis linear displacement system (4), the upper end of the vertical measuring arm (6) is installed on the moving part of the X-axis linear displacement system (5), and the laser displacement probe (7) is installed on the lower end of the vertical measuring arm (6). The Z-axis linear displacement system (4) and the X-axis linear displacement system (5) drive the laser displacement probe (7) to move in the vertical and horizontal directions respectively to complete the scanning of the measuring point.

5. The Wolter-I type reflective mirror barrel surface shape accuracy non-contact detection system according to claim 4, characterized in that, The Z-axis linear displacement system (4) and the X-axis linear displacement system (5) are configured with linear grating rulers to form a closed-loop displacement system with a repeatability accuracy better than 0.5μm. The grating ruler is installed on the fixed part of the displacement system, and the reading head is installed on the moving part of the displacement system. The position detection signal of the linear grating ruler is fed back to the control and data acquisition platform (11) for the position control of the laser displacement probe (7).

6. The Wolter-I type reflector tube surface shape accuracy non-contact detection system according to claim 1, characterized in that, The end runout and radial runout of the air-floating turntable (8) are both better than 0.1 μm, and the rotation accuracy is 0.2". The laser displacement probe (7) is a non-contact optical probe with a resolution better than 30nm, a measurement accuracy of 0.75μm, and a diameter of 20mm. To avoid interference between the laser displacement probe (7) and the reflector tube, the diameter of the reflector tube is ≥120mm.

7. A non-contact method for detecting the surface shape accuracy of a Wolter-I type reflective mirror barrel, characterized in that, This is achieved using a non-contact detection system for the surface shape accuracy of a Wolter-I type reflector tube as described in any one of claims 1-6, comprising: S1 activates compressed air, allowing the air-floating turntable (8) to rotate freely; S2 uses a tray (9) to mount the reflector tube to be tested onto the air-bearing turntable (8), with the large-diameter end of the reflector tube facing upwards; S3 starts the control and data acquisition platform (11), and uses the tray (9) and the control and data acquisition platform (11) to complete the horizontal and center adjustment of the reflector tube; controls the laser displacement probe (7) to move to the upper end of the inner wall of the reflector tube under test, and records the Z-axis coordinate of the laser displacement probe (7) as H, then controls the laser displacement probe (7) to move to the lower end of the inner wall of the reflector tube under test, and records the Z-axis coordinate of the laser displacement probe (7) as h; the Z-axis is along the vertical direction; S4 generates a planned path based on H and h, and the control and data acquisition platform (11) controls the laser displacement probe (7) to obtain the coordinate values ​​of each measuring point on the inner wall of the reflector tube in sequence according to the planned path; The S5 control and data acquisition platform (11) processes the coordinate values ​​of the inner wall of the reflector tube to give the surface accuracy of the reflector tube under test.

8. The non-contact detection method for the surface shape accuracy of a Wolter-I type reflector tube according to claim 7, characterized in that, The pallet (9) includes a chuck body (91) and micro heads; the chuck body (91) is a disc-shaped structure, and the lower end face of the chuck body (91) is supported by three micro heads evenly distributed in the circumferential direction, and four micro heads (92) are evenly distributed in the circumferential direction on the upper surface of the chuck body (91). In step S3, the method for adjusting the horizontal and center of the reflector tube includes coarse horizontal and coarse center adjustment of the reflector tube, or, after coarse horizontal and coarse center adjustment of the reflector tube, fine horizontal and fine center adjustment are performed. The methods for horizontal coarse adjustment and center coarse adjustment include: By adjusting the three micrometer heads on the lower end face of the chuck body (91), the angle between the upper surface of the tray (9) and the horizontal plane is less than 10′, thus achieving coarse horizontal adjustment of the reflector tube; by adjusting the four micrometer heads on the upper surface of the chuck body (91) and adjusting the position of the reflector tube, so that all four micrometer heads are in contact with the outer surface of the reflector tube, and then the micrometer heads are moved back half a turn to avoid applying external force to the reflector tube, so that the distance between the center of the reflector tube and the rotation center of the air-bearing turntable (8) is less than 0.2 mm, thus achieving coarse center adjustment of the reflector tube; The methods for horizontal and center fine adjustment include: the control and data acquisition platform (11) controls the laser displacement probe (7) to obtain the coordinate values ​​of each measuring point on the inner wall of the reflector tube, and adjusts the three micro heads on the lower end face of the chuck body (91) and the four micro heads on the upper surface of the chuck body (91) according to the coordinate values ​​to realize the horizontal and center fine adjustment of the reflector tube.

9. The non-contact detection method for the surface shape accuracy of a Wolter-I type reflector tube according to claim 7, characterized in that, In step S4, the planned path includes: obtaining the coordinate values ​​of each measuring point on the first busbar from bottom to top, then rotating the reflector tube through a predetermined angle to obtain the coordinate values ​​of each measuring point on the next busbar, until the measurement of the entire inner surface of the reflector tube is completed; when obtaining the coordinate values ​​of each measuring point on each busbar from bottom to top, the distance between the laser displacement probe (7) and the inner surface of the reflector tube remains unchanged. Set z in the control and data acquisition platform (11) i z and n are used as path planning parameters, where z i The z-axis coordinates are the distance from the lowest measuring point to the highest measuring point. i = h + (i-1)·d, i = 1, 2, 3, ..., m, where i represents the i-th measurement point and m is the total number of measurement points on the same generatrix. d is the step size for measuring along the generatrix; n is the number of generatrixes measured uniformly along the circumference, n≥4.

10. The non-contact detection method for the surface shape accuracy of a Wolter-I type reflector tube according to claim 7, characterized in that, In step S5, the method for obtaining the surface shape accuracy of the tested reflector tube includes: Suppose the measured coordinates of the inner wall of the reflecting mirror tube are (x i y i , z i The coordinates of the ideal surface shape of the corresponding reflector tube are (x...). i ' ,y i ' ,z i If the surface shape error value at each measuring point is..., then the surface shape error value at each measuring point is... Root mean square value of surface accuracy Where k is the total number of measurement points.

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