Portable device and measuring method for roundness precision detection and diameter value fitting of large wallboard

Abstract

The invention discloses a portable device for roundness precision detection and diameter value fitting of a large wallboard and a measurement method, and the device comprises a measurement fixing support which is used for fixing a plurality of displacement sensors and is provided with a plurality of sensor installation holes which are symmetric about a center pair; the supporting column is used for supporting the measurement fixing support on the diameter calibrator; the diameter calibrator is consistent with the radius of the detected wall plate and serves as a standard device to calibrate the displacement sensor; the displacement sensor is used for detecting the displacement relative to the detected wall plate; the data acquisition card is used for transmitting detection data of the displacement sensor to the computer; and the computer is used for obtaining the roundness of the detected wallboard according to the data detected by the displacement sensor and the coordinate data and carrying out fitting circle calculation. According to the measuring method, the diameter of the wallboard is fitted in upper computer software by adopting a least square method according to position coordinates and measured values of the displacement sensors, and roundness measurement and diameter value fitting of the large wallboard are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of on-site precision detection of roundness values and diameter dimensions of large wall panels, and particularly relates to a portable device and a measurement method for precision detection of roundness and diameter value fitting of large wall panels. Background Art

[0002] In industrial production such as aerospace, the application of curved wall panels is very extensive. During the processing of curved wall panels, due to the action of various external factors such as the initial state of raw materials, roll bending pressure, vibration and thermal deformation during cutting, and internal residual stress, local or overall deformation will occur, resulting in roundness deviation of the wall panels. The roundness deviation of the wall panels will affect the precise guarantee of the wall thickness dimension of the workpiece and have a negative impact on the strength and stress state of the product. Therefore, it is crucial to establish a high-precision wall panel roundness and diameter measurement device and measurement method.

[0003] In traditional wall panel processing, there are mainly two measurement schemes:

[0004] First, the measurement of the roundness and diameter of large wall panels mainly relies on special measuring tools for comparative measurement. The special measuring tools are arc plates cut according to the required dimensions, and the roundness of the wall panels is judged by fitting and comparing with the wall panels. This scheme has the following disadvantages:

[0005] (1) After manually estimating the gaps at each part, a feeler gauge is used to measure the gap values at each position in turn. The size of the feeler gauge needs to be adjusted multiple times during the measurement process at each point, resulting in low measurement efficiency and poor accuracy;

[0006] (2) The selection of measurement positions and quantities depends on the operator, with large randomness, which is not conducive to the accumulation and analysis of process data; it is impossible to optimize process parameters and realize digital production;

[0007] (3) Only the deviation value from the special tooling can be obtained by comparison, and the specific roundness and diameter values cannot be obtained, resulting in an incomplete evaluation of large wall panels;

[0008] (4) Special measuring tools can only measure in a small range, and multiple sets of special measuring tools need to be prepared for measuring wall panels of different specifications;

[0009] (5) The measurement result is the deviation value between the special measuring tool and the workpiece, and the shape of the workpiece cannot be intuitively reflected;

[0010] (6) The measurement process adopts a mode of measuring while manually recording, which requires multiple operators, has low efficiency, and has quality risks of missing records and wrong records;

[0011] Second, the measurement of the roundness and diameter of large wall panels is carried out on special equipment such as a coordinate measuring machine. This scheme can obtain relatively accurate roundness and diameter data and can comprehensively evaluate the parts, but this scheme has the following unacceptable disadvantages:

[0012] (1) After the workpiece is removed from the site and sent to the testing agency for measurement, subsequent reprocessing requires secondary clamping, resulting in large errors.

[0013] (2) After the workpiece is removed, deformation occurs due to stress release, and it cannot be restored to the state before removal during secondary clamping, resulting in the inability to guarantee some characteristic dimensions (such as wall thickness).

[0014] (3) The process chain is long during the inspection process, extending the manufacturing cycle.

[0015] The disadvantages of the above two solutions do not meet the requirements of efficient and high-quality manufacturing. The device and method of the present invention can achieve rapid, convenient, high-precision, and digital measurement of such parts at the production site, with incomparable advantages. Summary of the Invention

[0016] The purpose of the present invention is to provide a portable device and measurement method for precision roundness detection and diameter value fitting of large wall panels, so as to achieve roundness measurement and diameter value fitting of large wall panels.

[0017] The technical solution to achieve the purpose of the present invention is as follows:

[0018] A portable device for precision roundness detection and diameter value fitting of large wall panels, comprising:

[0019] A measurement fixing bracket for fixing a plurality of displacement sensors, with a plurality of sensor mounting holes symmetrically arranged with the center pair.

[0020] Support columns for supporting the measurement fixing bracket on the diameter calibrator.

[0021] A diameter calibrator, which is consistent with the radius of the wall panel to be measured and serves as a standard device to zero the displacement sensors.

[0022] Displacement sensors for detecting the displacement relative to the wall panel to be measured.

[0023] A data acquisition card for transmitting the detection data of the displacement sensors to a computer.

[0024] A computer for obtaining the roundness of the wall panel to be measured based on the data detected by the displacement sensors and the coordinate data and performing fitting circle calculation.

[0025] A measurement method for a portable device for precision roundness detection and diameter value fitting of large wall panels includes:

[0026] Step 1: Before the measurement starts, determine the composition of the measurement fixing bracket according to the size of the wall panel to be measured and assemble the measurement fixing bracket.

[0027] Step 2: Install the support columns on the measurement fixing bracket to ensure that the heights of the support columns are the same.

[0028] Step 3: Install the displacement sensors in the mounting holes on the measurement fixing bracket in sequence and pre-fix them with screws.

[0029] Step 4: Select a diameter calibrator according to the theoretical diameter of the wall panel to be measured, and require that the deviation between the theoretical diameter of the measured part and the diameter of the diameter calibrator is not more than 3 mm.

[0030] Step 5: Place the measurement device equipped with the support column and displacement sensors on the diameter calibrator, and ensure that there is no gap between the spherical head of the support column and the cylindrical surface of the diameter calibrator.

[0031] Step 6: Make the displacement sensor in the middle position on the arc center line of the diameter calibrator.

[0032] Step 7: Fine-tune the displacement sensor to ensure that the displacement sensor has enough range for measurement.

[0033] Step 8: Zero the displacement sensors of multiple channels in the upper computer. After zeroing, place the entire device on the wall panel to be measured, and ensure that the displacement sensor at the very center of the device is located at the center of the circle of the wall panel; read the values of each displacement sensor in the upper computer.

[0034] Step 9: Roundness calculation: Assume that there are a total of 2n - 1 displacement sensors, the number of the leftmost sensor is 1, and the middle displacement sensor is the nth sensor. Convert the vertical change amount detected by the displacement sensor into a radius change amount:

[0035]

[0036] where Δt is the vertical change amount detected by the displacement sensor, Δr is the radius change amount, l is the distance between adjacent displacement sensors, m is the number of the sensor from the middle nth sensor, R is the standard diameter of the diameter calibrator, and r is the diameter of the probe circle of the displacement sensor.

[0037] Calculate the roundness value:

[0038] ΔK = max(Δr1, Δr2,... Δr 2n-1 ) - min(Δr1, Δr2,... Δr 2n-1 )

[0039] where Δr 2n-1 is the radius change amount of the 2n - 1th displacement sensor;

[0040] Step 10: Substitute the coordinates of the contact points of the displacement sensors and the wall panel to be measured into the following formula:

[0041]

[0042] where (a, b) are the coordinates of the center of the fitted circle, Ra is the radius of the fitted circle, (xi , y i ), which is the center coordinate of the i-th sensor, and the number of displacement sensors is 2n - 1.

[0043] Compared with the prior art, the significant advantages of the present invention are:

[0044] By using the roundness and diameter detection device of the present invention, the on-line measurement of the roundness of wall panels with different diameters can be realized, and the diameter of the wall panel can also be fitted according to the measured values. High-precision detection of the profile and diameter of large wall panels can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of a portable device for precise detection of the roundness of large wall panels and fitting of diameter values according to the present invention;

[0046] Figure 2 (a - d) are the composition diagrams of the measurement fixing bracket according to the present invention;

[0047] Figure 3 (a - b) are the schematic diagrams of different specification combinations of the measurement fixing bracket according to the present invention;

[0048] Figure 4 It is the structural diagram of the diameter calibrator according to the present invention;

[0049] Figure 5 (a - b) are the calibration schematic diagrams of the roundness and diameter detection device for large wall panels according to the present invention;

[0050] Figure 6 It is the schematic diagram of the lower computer control circuit according to the present invention;

[0051] Figure 7 (a - b) are the schematic diagrams of the data conversion principle of the displacement sensor according to the present invention;

[0052] Figure 8 (a - b) are the schematic diagrams of the workpiece measured by the roundness precision detection and diameter value fitting device for large wall panels according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0053] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0054] Combined with Figures 1 - 8 , a portable device for precise detection of the roundness of large wall panels and fitting of diameter values in this embodiment includes a measurement tooling and a measurement system: Among them,

[0055] The measurement tooling includes: a measurement fixing bracket 3, a diameter calibrator 4, and a support column 2; Combined with Figure 2(a-d), the measurement fixing bracket 3 is composed of five parts, all made of carbon steel by precision machining, grinding and splicing, and each part is connected by screws, including the middle part 3.1 of the measurement fixing bracket, the L-shaped connecting bracket 3.2 of the measurement fixing bracket, and the support mounting part 3.3 of the measurement fixing bracket. The lengths of each part are L1, L2, and L3 respectively. Among them, the middle part 3.1 of the measurement fixing bracket is located in the middle of the entire measurement fixing bracket 3. There are sensor mounting holes in the middle of the middle part 3.1 of the measurement fixing bracket, and an odd number of sensor mounting holes are arranged at equal intervals. The two L-shaped connecting brackets 3.2 of the measurement fixing bracket are symmetrically installed at both ends of the middle part 3.1 of the measurement fixing bracket. The support mounting part 3.3 of the measurement fixing bracket is installed at the end of the middle part 3.1 of the measurement fixing bracket. The support mounting part 3.3 of the measurement fixing bracket is symmetrically installed with respect to the middle part 3.1 of the measurement fixing bracket. There are sensor mounting holes on both the L-shaped connecting bracket 3.2 of the measurement fixing bracket and the support mounting part 3.3 of the measurement fixing bracket. By adjusting the fixing bracket combination, measurements within different diameter ranges can be achieved. When measuring a wall plate with a smaller diameter, only the L-shaped connecting brackets 3.2 of the measurement fixing bracket are symmetrically installed at both ends of the middle part 3.1 of the measurement fixing bracket. When measuring a wall plate with a larger diameter, the support mounting part 3.3 of the measurement fixing bracket is installed on the L-shaped connecting bracket 3.2 of the measurement fixing bracket.

[0056] The support column 2 is made of carbon steel. The upper part of the support column is cylindrical, and the bottom is spherical. A scale is engraved on the side of the support column, and it is installed at both ends of the measurement fixing support 3 by screws; the diameter calibrator 4 is ground from aluminum alloy, and the surface roundness accuracy is less than 0.01 mm.

[0057] The diameter calibrator 4 is a partial cylinder, and the chord length is greater than the maximum length of the measurement fixing bracket 3; its radius dimension R is determined according to the radius R' of the workpiece to be detected, and the difference between the two is not greater than 3 mm; the radius dimension tolerance of the diameter calibrator 4 is less than 0.03 mm, and the roundness accuracy is less than 0.01 mm; a diameter calibrator center line 4.2 perpendicular to the end face of the cylinder 4.1 is engraved on the arc surface of the diameter calibrator 4, and this line segment divides the arc into two equal parts.

[0058] The measurement system includes: a displacement sensor 1, a data acquisition card 5, and a host computer 6. The displacement sensor 1 is installed in the measurement fixing bracket 3 by screws. The data acquisition card 5 receives the signal from the displacement sensor 1 and sends the data to the host computer 6 using the RS485 communication protocol. The host computer 6 is programmed with QT. The host computer 6 converts the displacement signal collected by the data acquisition card 5 into a roundness value and fits the collected displacement signal into an arc diameter by the least squares method. The displacement sensor is a high-precision displacement sensor with a measuring range of ±2 mm and a measuring accuracy of 0.1 μm. The sensor body is cylindrical and the head is spherical;

[0059] The measuring method based on the above device includes:

[0060] Step 1: Before the measurement starts, determine the fixed bracket component modules according to the length dimension of the workpiece to be measured and assemble the fixed bracket;

[0061] The length of the measuring fixed bracket is determined by the number of combined modules:

[0062] The length of the measuring fixed bracket composed of 5 parts is: L = L1 + 2×L2 + 2×L3; as Figure 3 (a);

[0063] The length of the measuring fixed bracket composed of 3 parts is: L = L1 + 2×L3; as Figure 3 (b);

[0064] The arc-direction length of the workpiece of the wall panel to be measured should be greater than or equal to the length L of the measuring bracket; the measuring fixed bracket is evenly distributed with 19 displacement sensor mounting holes, which can be installed according to actual requirements.

[0065] Step 2: Install the support column 2 on the measuring fixed bracket 3.3 according to the side scale value, ensuring that the heights of the support columns are the same.

[0066] Step 3: Install the displacement sensors 1 in the mounting holes on the measuring fixed bracket 3 in sequence and pre-fix them with screws.

[0067] Step 4: Select a suitable diameter calibrator 4 according to the theoretical diameter of the workpiece to be measured, and require that the deviation between the theoretical diameter of the workpiece to be measured and the diameter of the diameter calibrator does not exceed 3 mm;

[0068] Step 5: Place the measuring device equipped with the support column 2 and the displacement sensors 1 on the diameter calibrator 4, ensuring that there is no gap between the spherical head of the support column and the cylindrical surface of the diameter calibrator; as Figure 5 (a);

[0069] Step 6: Adjust the horizontal position of the measuring device to make the displacement sensor in the middle position on the arc center line 4.2 of the diameter calibrator 4 as much as possible; as shown in Figure 5(b);

[0070] Step 7: Fine-tune the displacement sensors 1 to make the 0-point position of the displacement sensor correspond to the surface of the diameter calibrator 4 as much as possible, ensuring that the displacement sensor has enough range for measurement.

[0071] Step 8: Zero the displacement sensors of 19 channels in the upper computer. After zeroing, place the entire measuring device on the wall panel to be measured, and refer to Figure 8 (a - b) to ensure that the displacement sensor at the very center of the measuring device is located at the center of the circle of the wall panel. Read the values of each displacement sensor in the upper computer. According to the values of each sensor and the position coordinates of the sensors, the displacements of all sensors can be read out, and then the roundness can be calculated and the diameter of the wall panel can be fitted.

[0072] Step 9: Roundness calculation: Assume there are a total of 2n - 1 displacement sensors. The sensor with the leftmost number is 1. The value directly measured by the displacement sensor in the middle is the displacement perpendicular to the wall panel, rather than the profile value of the wall panel. Refer to Figure 7 (a - b). Assume the displacement sensor in the middle is the nth sensor. The distance between adjacent displacement sensors is l. The (m + n)th displacement sensor is m l intervals away from the nth displacement sensor. The distance between the nth displacement sensor and the (m + n)th displacement sensor is m·l. According to the trigonometric function formula, the included angle between the (m + n)th displacement sensor and the center of the circle is R is the standard diameter of the diameter calibrator, and r is the diameter of the displacement sensor probe tip circle. According to the trigonometric transformation relationship, the vertical change of the displacement sensor can be converted into the radius change. The transformation formula is: where Δt is the value of the displacement sensor, and Δr is the profile value (i.e., the radius change) at this value. Record the profile values of each sensor in sequence as: Δr1, Δr2,... Δr 2n-1 ; The difference between its maximum value and minimum value is the roundness value of the wall panel (also known as the profile value of the wall panel). The calculation formula is as follows:

[0073] ΔK = max(Δr1, Δr2,... Δr 2n-1 ) - min(Δr1, Δr2,... Δr 2n-1 )

[0074] In the calibration stage of the measuring device, write the profile transformation formula corresponding to each displacement sensor into the software in the upper computer respectively to reduce the profile measurement error.

[0075] Step 10: Fitting circle calculation: The least squares fitting circle is a classic curve fitting method, which is very useful in processing measurement data. Especially when there is noise or error in the measurement data, the best fitting circle can be found by minimizing the sum of the squares of the errors. Substitute the coordinates of the contact points between the displacement sensors and the workpiece into the following formula to obtain the following formulas for solving a, b, and r:

[0076]

[0077] where (a, b) is the coordinate of the center of the fitting circle, Ra is the radius of the fitting circle, and (x1, y1)(x2, y2)...(x i , y i )...(x 2n-1,2n-1 ) are the coordinates of the centers of each sensor. In the upper computer software, convert and process the values of each sensor channel and calculate to automatically obtain the diameter value and center coordinate of the fitting circle.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than restrictive technical solutions. Those of ordinary skill in the art should understand that any modifications or equivalent replacements made to the technical solutions of the present invention without departing from the purpose and scope of the present technical solutions shall be covered by the scope of the claims of the present invention.

Claims

1. A portable device for precise roundness detection and diameter value fitting of large wall panels, characterized in that: include: A measuring fixing bracket is used to fix a plurality of displacement sensors, and a plurality of sensor mounting holes are provided symmetrically with the center pair; A support column, used for supporting the measuring fixture on the diameter calibrator; The diameter calibrator, which is consistent with the radius of the wall panel being measured, is used as a standard device to calibrate the displacement sensor to zero; A displacement sensor is used to detect the displacement relative to the measured wall plate; A data acquisition card is used to transmit the detection data of the displacement sensor to a computer; The computer is used to obtain the roundness of the measured wallboard according to the data detected by the displacement sensor and the coordinate data and to perform fitting circle calculation.

2. The portable device for precise roundness detection and diameter value fitting of large wall panels according to claim 1 is characterized in that: The process of the computer obtaining the roundness of the measured wallboard is as follows: Convert the vertical change detected by the displacement sensor into the radius change: Where Δt is the vertical change detected by the displacement sensor, Δr is the radius change, l is the distance between adjacent displacement sensors, m is the number of the nth sensor in the middle of the distance, R is the standard diameter of the diameter calibrator, and r is the displacement sensor probe circle diameter; Calculate the roundness value: ΔK=max(Δr1、Δr2、…Δr 2n-1 )-min(Δr1、Δr2、…Δr 2n-1 ) Where Δr 2n-1 is the radius change of the 2n-1th displacement sensor.

3. The portable device for precise roundness detection and diameter value fitting of large wall panels according to claim 1 is characterized in that: The process of the computer performing fitting circle calculation is as follows: Substitute the coordinates of the contact point between the displacement sensor and the measured wall panel into the following formula: Where (a, b) is the coordinate of the center of the fitting circle, Ra is the radius of the fitting circle, (x i ,y i ) is the coordinate of the center of the i-th sensor, and the number of displacement sensors is 2n-1.

4. The portable device for precise roundness detection and diameter value fitting of large wall panels according to claim 1 is characterized in that: The measuring fixed bracket comprises a measuring fixed bracket middle part, a measuring fixed bracket L-shaped connecting bracket, and a measuring fixed bracket supporting and installing part; wherein the measuring fixed bracket middle part is located in the middle of the entire measuring fixed bracket, a sensor installing hole is provided in the middle of the measuring fixed bracket middle part, and an odd number of sensor installing holes are provided at equal intervals; two measuring fixed bracket L-shaped connecting brackets are symmetrically installed at both ends of the measuring fixed bracket middle part, a measuring fixed bracket supporting and installing part is installed at the end of the measuring fixed bracket middle part, the measuring fixed bracket supporting and installing part is symmetrically installed about the measuring fixed bracket middle part, and sensor installing holes are provided on the measuring fixed bracket L-shaped connecting bracket and the measuring fixed bracket supporting and installing part.

5. The portable device for precise roundness detection and diameter value fitting of large wall panels according to claim 1 is characterized in that: The upper part of the support column is cylindrical, the bottom is spherical, and a scale is engraved on the side of the support column.

6. The portable device for precise roundness detection and diameter value fitting of large wall panels according to claim 1 is characterized in that: The chord length of the diameter calibrator is greater than the maximum length of the measuring fixed bracket, and a diameter calibrator center line perpendicular to the end face of the cylinder is engraved on the arc surface.

7. The portable device for precise roundness detection and diameter value fitting of large wall panels according to claim 1 is characterized in that: The diameter calibrator has a radius tolerance of less than 0.03 mm and a roundness accuracy of less than 0.01 mm.

8. The portable device for precise roundness detection and diameter value fitting of large wall panels according to any one of claims 1 to 7, characterized in that: The measurement methods include: Step 1: Before the measurement begins, determine the composition of the measurement fixing bracket according to the size of the wall panel to be measured and combine the measurement fixing bracket; Step 2: Install the support column on the measurement bracket to ensure that the height of the support column is consistent; Step 3: Install the displacement sensors in the mounting holes on the measurement fixing bracket in sequence and pre-fix them with screws; Step 4: Select a diameter calibrator based on the theoretical diameter of the wall panel being measured, and the deviation between the theoretical diameter of the measured piece and the diameter of the diameter calibrator should not exceed 3mm; Step 5: Place the measuring device with the support column and displacement sensor installed on the diameter calibrator, ensuring that there is no gap between the ball head of the support column and the cylindrical surface of the diameter calibrator; Step 6: Make the displacement sensor in the middle position on the center line of the arc surface of the diameter calibrator; Step 7: Fine-tune the displacement sensor to ensure that it has sufficient measurement range. Step 8: Zero the displacement sensors of multiple channels in the host computer. After zeroing, place the entire device on the wall plate to be tested, ensuring that the displacement sensor at the center of the device is located at the center of the wall plate; read the value of each displacement sensor in the host computer; Step 9: Calculation of roundness: Assume that there are 2n-1 displacement sensors in total, the leftmost sensor is numbered 1, and the middle displacement sensor is sensor numbered n. Convert the vertical change detected by the displacement sensor into the radius change: Where Δt is the vertical change detected by the displacement sensor, Δr is the radius change, l is the distance between adjacent displacement sensors, m is the number of the nth sensor in the middle of the distance, R is the standard diameter of the diameter calibrator, and r is the displacement sensor probe circle diameter; Calculate the roundness value: ΔK=max(Δr1、Δr2、…Δr 2n-1 )-min(Δr1、Δr2、…Δr 2n-1 ) Where Δr 2n-1 is the radius change of the 2n-1th displacement sensor; Step 10: Substitute the coordinates of the contact point between the displacement sensor and the measured wall panel into the following formula: Where (a, b) is the coordinate of the center of the fitting circle, Ra is the radius of the fitting circle, (x i ,y i ) is the coordinate of the center of the i-th sensor, and the number of displacement sensors is 2n-1.

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