Method and device for measuring diameter and coaxiality of cylindrical or conical devices

Abstract

The present invention discloses a method for measuring the diameter and coaxiality of a cylindrical or conical device and a measuring device thereof. The measuring device comprises a measuring cylinder having at least two layers of annular sensor brackets arranged from top to bottom, each layer of which has N distance measuring sensors arranged radially along the circumference, where N is greater than or equal to 3. The top surface of the measuring cylinder is provided with a suspension flange that can be supported on the upper end of the device being measured. The diameter and coaxiality measuring method includes calibrating the N distance measuring sensors on each layer of the sensor brackets on the measuring device using a standard circular ring to obtain the positional relationship between the sensors; performing actual measurement and calculation on the device being measured to obtain the diameter d of the cross-sectional circles at different heights within the cylinder of the device being measured. i , center coordinates O i (x i ,y i The method of the present invention is simple, has high measurement accuracy, requires low sensor installation accuracy and manufacturing accuracy of the measuring equipment, has low equipment investment and operation difficulty, and can be measured automatically.

Description

Technical Field

[0001] The invention relates to the field of equipment measurement, in particular to a method for measuring the diameter and coaxiality of a cylindrical or conical device and a measuring device thereof. Background Art

[0002] Some cylindrical or conical devices will have inner wall wear after long-term or repeated use. For example, some cylindrical devices have four rings inside the cylinder. Changes in the ring diameter and coaxiality will affect subsequent normal use. When the wear is too severe, they need to be replaced in time.

[0003] In order to promptly detect the wear status of the inner wall, manual measurements need to be performed regularly using a laser tracker. For large cylindrical or conical devices, people need to be lifted into the cylinder by crane each time to measure each section of the ring. However, such equipment often has problems such as small inner diameter, harsh measurement environment, and poor safety. Manual operation is extremely inconvenient and the measurement error is large. Summary of the Invention

[0004] The purpose of the present invention is to solve the above technical problems and provide a method for measuring the diameter and coaxiality of cylindrical or conical devices, which is simple and effective in improving measurement accuracy, while reducing the installation accuracy of the sensor and the manufacturing accuracy of the measuring equipment, reducing equipment investment and operation difficulty, and realizing automated measurement.

[0005] The present invention also provides a diameter and coaxiality measuring device which has a simple structure, is easy to operate, saves time and effort, and can completely replace manual operation.

[0006] The diameter and coaxiality measuring device of the present invention includes a measuring cylinder, the outer circumference of which is provided with at least two layers of annular sensor brackets from top to bottom, each layer of sensor brackets having N distance measuring sensors arranged radially along the circumference, N ≥ 3, and the top surface of the measuring cylinder is provided with a suspension flange that can be supported on the upper end of the device being measured.

[0007] The hanging flange is also provided with a lifting and rotating assembly for lifting and rotating the measuring cylinder.

[0008] The jacking and rotating assembly includes a cover plate located above the hanging flange and a jacking and rotating bracket. The cover plate is fixed to the hanging flange by bolts. A hydraulic cylinder is provided on the jacking and rotating bracket. The piston rod of the hydraulic cylinder is connected to the cover plate. A plurality of vertical jacking rods with the lower ends passing through the hanging flange are evenly arranged around the circumference of the jacking and rotating bracket. The lower ends of the jacking rods are provided with bearings that can contact the upper end surface of the device under test.

[0009] The radial outer peripheral surface of the suspension flange is provided with at least two symmetrical limiting blocks, and the limiting blocks correspond one-to-one to the limiting grooves on the upper end of the device under test.

[0010] A plurality of elastic universal wheels are evenly arranged on the outer peripheral surface of the measuring cylinder.

[0011] To address the problems in the prior art, the inventors have designed a device suitable for measuring the diameter and coaxiality of the inner cylinder of cylindrical or conical devices. The measuring cylinder can be equipped with multiple sensor brackets as needed. The number and height of these multiple sensor brackets can be rationally designed based on the area of the device being measured. For coaxiality measurement, at least two annular sensor brackets are required. The measuring cylinder can be hoisted and inserted into the cylinder of the device being measured, replacing manual measurement.

[0012] Furthermore, for large-sized devices under test, when measuring coaxiality, it is necessary to lift and rotate the measuring device. Due to the large size and weight of the bracket, it is time-consuming and labor-intensive to operate by workers, and the safety is poor. Therefore, a lifting and rotating assembly for lifting and rotating the measuring cylinder is also provided on the hanging flange. The hydraulic cylinder on the lifting and rotating bracket is cleverly used to apply force to the cover plate, thereby driving the hanging flange to lift out of the limit through the bolts, and at the same time, the lower end of the lifting rod of the lifting and rotating bracket is supported on the upper end surface of the device under test, so that the supporting force is transferred from the hanging flange to the upper end surface of the lifting rod. Since the lower end of the lifting rod is provided with a bearing that can slide on the upper end surface of the device under test, the measuring device as a whole can be rotated on the upper end surface of the device under test by easily pushing the lifting and rotating bracket, so that the measuring device can rotate 180 degrees with the axial center as the center of the circle; after completing the 180-degree rotation, the upper cover plate is controlled to descend by the hydraulic cylinder, so that the hanging flange can be lowered into the limit groove, and the measuring device can be suspended and supported again. The structure is simple and compact, does not require a large lifting mechanism, is extremely easy to operate, and only uses a hydraulic cylinder to provide power, making it very suitable for measurement work in harsh environments.

[0013] The present invention provides a method for measuring the diameter and coaxiality of a cylindrical or conical device, comprising the following steps:

[0014] 1. Sensor calibration: Use a standard ring to calibrate the N distance measuring sensors on each layer of the sensor bracket on the measuring device, and obtain the distance a when the laser emitted by each distance measuring sensor on each layer of the sensor bracket hits the standard ring. i , combined with the standard ring radius r0, the actual installation angle θ of each ranging sensor is obtained by calculation and fitting i and the coordinates A of the origin of the light source of each ranging sensor i (x i ,y i ), and save the data;

[0015] 2. Measurement: The measuring device is vertically hoisted into the tube of the device under test from the top opening of the device under test and fixed in place. Then the first measurement is performed to obtain the distance b between the laser emitted by each ranging sensor on each layer of the sensor bracket and the inner wall of the device under test. i , combined with the actual installation angle θ of the corresponding distance sensor saved in step 1) i and the coordinate A of the origin of the ranging sensor light source i (x i ,y i ), calculate and fit the diameter d and center coordinate O of the cross-section circle of the device under test corresponding to the N distance measuring sensors on the sensor bracket of this layer, so as to obtain the diameter d of the cross-section circle at different heights in the cylinder of the device under test i and the center coordinates O i (x,y).

[0016] After step 2, there is also

[0017] 3. Coaxiality calibration: After completing the first measurement, the measuring device is rotated 180 degrees around the axial center for a second measurement to obtain the distance b between the laser emitted by each ranging sensor on each layer of the sensor bracket and the inner wall of the device being measured. i ', combined with the actual installation angle θ of the corresponding distance sensor saved in step 1) i and the coordinates P of the origin of the ranging sensor light source Ai ′(x1,y i ), calculate and fit the diameter d1′ and center coordinate O′ of the cross-section circle of the device under test corresponding to the N distance measuring sensors on the sensor bracket of this layer, so as to obtain the diameter d′ and center coordinate O′ of the cross-section circle at different heights in the cylinder of the device under test. i ′(x i ,y i );

[0018] According to actual needs, the center coordinates of a certain height cross-section circle are used as the reference center coordinates for fitting, and the vector relationship between the center coordinates of other cross-section circles at different heights and the center reference coordinates of the circle is calculated during the first and second measurements respectively;

[0019] The vector relationship data obtained from the two measurements are correspondingly subtracted to obtain the center coordinates of the corrected cross-section circles at different heights, thereby obtaining the coaxiality of the device under test.

[0020] Preferably, the first step is to establish a rectangular coordinate system Ao with the straight line on which any one of the N ranging sensors on a certain layer of sensor brackets emits a laser as the positive Y axis, the straight line to the right passing through the light source point perpendicular to the laser as the positive X axis, and the center of the light source point of the ranging sensor as the center of the circle;

[0021] Assume that the angles between the N distance measuring sensors of this layer and the X axis are θ1, θ2, θ3, ... θn (θ1 = 90°), and the coordinates of the light source origins of the N distance measuring sensors are A1(x1, y1), A2(x2, y2), ..., A N (x n ,y n ), during calibration, the distances at which the lasers emitted by N ranging sensors hit the standard circle are a1, a2, ...a n , the radius of the standard ring is r0, and the coordinates of the center of the circle are O p (x, y), then the coordinates of the lasers emitted by N ranging sensors on the standard ring are: P A1 (0, a1), P A2 (x2+a2*cosθ2, y2+a2*sinθ2),...P AN (x n +a n *cosθ n ,y n +a n *sinθ n ), and the following N equations are obtained by the Pythagorean theorem:

[0022] x 2 +(a1-y) 2 =r0 2

[0023] (x²+a²*cosθ²-x) 2 +(y²+a²*sinθ²-y) 2 =r0 2

[0024] …

[0025] (x n +a n *cosθ n -x) 2 +(y n +a n *sinθ n -y) 2 =r0 2

[0026] Using the above method, by adjusting the position of the standard ring, M measurements are performed. Each measurement will form N equations. M measurements will form N*M equations. After M measurements, N*M-1 unknown measurements will be obtained. The coordinates of point A1 are (0,0) and the angle is 0. Because N ≥ 3, when M ≥ 4, the number of equations is greater than the number of unknowns, and the equations can be solved to obtain the positional relationship between the N sensors in this layer, including the actual installation angle θ of each ranging sensor.i and the coordinates A of the origin of the light source of each ranging sensor i (x i ,y i );

[0027] Similarly, the relevant parameters of the positional relationship of the N distance measuring sensors on each layer of the sensor bracket are calculated and saved.

[0028] Obtain the surface temperature of the calibration ring during calibration and the surface temperature of the device under test during measurement. If there is a temperature difference between the two, compensate according to the following formula:

[0029]

[0030] Where: L is the measured length;

[0031] δ1, δ2 are the linear expansion coefficients of the calibration ring and the device under test respectively

[0032] t1, t2 - the actual temperatures of the calibration ring and the device under test respectively

[0033] The diameters d of the two measurements i and d i The average value of ′ plus Get the final measurement of the final diameter.

[0034] Considering the need to ensure measurement accuracy while reducing equipment costs and operational difficulty, the inventors made improvements in two areas. First, they used a standard circular ring to calibrate the installed distance sensor. This method minimized the installation angle error of the distance sensor, thereby lowering the actual installation accuracy requirements for the distance sensor and reducing production and operational difficulties. Second, considering that the manufacturing precision of the measuring cylinder is high when the device under test is long, which increases the manufacturing difficulty and production cost, the inventors addressed this by rotating the measuring device 180 degrees after obtaining relevant data from the first measurement and then performing a second measurement. The two data sets were then fitted to eliminate errors caused by production precision.

[0035] Furthermore, in view of the possibility of temperature differences between the calibration environment and the measurement environment of the measuring device, as well as the differences in the thermal expansion coefficients of the calibration ring and the material of the device under test, compensation is performed when the calibration environment temperature and the measurement environment temperature are different, thereby further improving the measurement accuracy.

[0036] The device of the present invention has a simple and compact structure, is easy to operate, and can achieve actions such as suspension, lifting, and rotation on the device being measured, fully meeting measurement requirements while offering low production difficulty and manufacturing costs. The method of the present invention takes into account issues such as sensor installation angle error and the production accuracy of the measuring device. Sensor calibration is performed before measurement and coaxiality correction is performed after measurement. This significantly improves measurement accuracy, reduces measurement difficulty and production costs, effectively replaces manual operation, and achieves automated measurement. It is unaffected by various harsh environments and is suitable for measuring the diameter and coaxiality of various cylindrical or conical devices with internal holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the structure of the measuring device of the present invention.

[0038] Figure 2 This is a schematic diagram of the partial installation of the jacking and rotating components.

[0039] Figure 3 for Figure 2 A-direction view.

[0040] Figure 4 Schematic diagram of the arrangement of multiple ranging sensors on each layer of sensor bracket.

[0041] Figure 5 Schematic diagram of the device under test in the embodiment.

[0042] Figure 6 Schematic diagram of the relative positions of the first layer of sensors and the original zero position in the embodiment.

[0043] Figure 7 Schematic diagram of relevant parameters of the position relationship of the first layer of sensors.

[0044] Figure 8 is the fitted circle-centered stereogram.

[0045] Figure 9 Schematic diagram of fitting center deviation.

[0046] Among them, 1-cover plate, 2-hydraulic cylinder, 3-bolt, 4-lifting rotating bracket, 5-suspension flange, 5.1-limit block, 6-measured device, 6.1-limit slot, 7-measuring cylinder, 8-sensor bracket, 9-lifting rod, 10-bearing, 13-elastic universal wheel, 14-distance measuring sensor. DETAILED DESCRIPTION

[0047] The present invention will be further explained below with reference to the accompanying drawings:

[0048] Device Example:

[0049] See also Figure 1The measuring cylinder 7 can be a cylindrical bracket or cylinder wall, and its outer circumference is provided with at least two layers of annular sensor brackets 8 from top to bottom (four layers in this example), and each layer of sensor brackets 8 is radially arranged along the circumference with N distance measuring sensors 14, N ≥ 3, see Figure 4 In this embodiment, 9 distance measuring sensors 14 are evenly arranged on each layer of sensor bracket 8, and the top surface of the measuring cylinder 7 is provided with a hanging flange 5 that can be supported on the upper end of the device under test 6; a plurality of elastic universal wheels 13 are also evenly arranged on the outer circumference of the measuring cylinder 7 to prevent the distance measuring sensors 14 from directly colliding with the inner wall of the device under test 6 during the lifting process.

[0050] The suspension flange 5 is also provided with a lifting and rotating assembly for lifting and rotating the measuring cylinder 7. Figure 2 and Figure 3 The lifting and rotating assembly includes a cover plate 1 and a lifting and rotating bracket 4 located above the hanging flange 5. The cover plate 1 is fixed to the hanging flange 5 by bolts 3. The lifting and rotating bracket 4 is provided with a hydraulic cylinder 2, and the piston rod of the hydraulic cylinder 2 is connected to the cover plate 1. The circumference of the lifting and rotating bracket 4 is evenly provided with a plurality of vertical lifting rods 9, the lower ends of which pass through the hanging flange 5. The lower ends of the lifting rods 9 are provided with bearings 10 that contact the upper end surface of the device under test 6. The radial outer periphery of the hanging flange 5 is provided with at least two symmetrical limit blocks 5.1, and the limit blocks 5.1 correspond one-to-one with the limit grooves 6.1 on the upper end of the device under test 6. In this embodiment, the hanging flange 5 is provided with two symmetrical limit blocks 5.1, and correspondingly, the device under test is provided with two symmetrical limit grooves 6.1, and the limit blocks 5.1 can be correspondingly embedded in the limit grooves 6.1.

[0051] Working principle of the measuring device: Before the first measurement, the measuring device of the present invention is hoisted into the inner tube of the device under test 6, so that the limit block 5.1 on the hanging flange 5 is exactly aligned and embedded in the limit groove 6.1, so that the hanging flange 5 exactly covers the upper end surface of the device under test 6, so that the measuring device is in a suspended state, and then the first measurement is performed;

[0052] After the first measurement is completed, the hydraulic cylinder 2 is controlled to apply an upward force to the cover plate 1, thereby driving the suspension flange 5 to lift up through the bolt 3, and the limit block 5.1 rises and disengages from the limit groove 6.1. At the same time, the jacking and rotating bracket 4 is subjected to the force of the hydraulic cylinder 2, so that the lower end of the jacking rod 9 is supported by force on the upper end surface of the device under test 6, thereby realizing the conversion of the supporting force; since the lower end of the jacking rod 9 is provided with a bearing 10 that can slide on the upper end surface of the device under test 6, the jacking and rotating bracket 4 can be easily pushed by manual or power equipment to rotate the entire measuring device on the upper end surface of the device under test 6, realizing the measurement device rotating 180 degrees with the axial center as the center of the circle; when the 180-degree rotation is completed, the upper cover plate 1 is controlled to descend by the hydraulic cylinder 2, which can cause the suspension flange 5 to descend accordingly, and the limit block 5.1 falls into the limit groove 6.1. The suspension flange 5 once again assumes the suspension support function of the measuring device, and the second measurement is started after the rotation is completed.

[0053] The distance measuring sensor 14 can be connected to the control system, and the collected data is input into the control system for analysis and calculation. The hydraulic cylinder 2 can also be connected to the control system, and the control system controls the movement of the hydraulic cylinder 2. The analysis and calculation results can be output through a display and / or output device.

[0054] Method Example:

[0055] In the following embodiment, it is assumed that four layers of sensor brackets 8 are arranged on the measuring cylinder 7. The specific height of the sensor brackets 8 is determined according to the key parts to be measured in the inner cylinder of the device to be measured 6. For example, the cylindrical device described in the background technology has four sections of circular ring structures in the cylinder, among which the topmost circular ring structure is set as the reference circle. When it is necessary to measure the corresponding diameters and coaxiality of these four sections of circular rings, the installation position of the sensor bracket 8 should ensure that the laser emitted by the ranging sensor 14 of each layer can hit the corresponding circular ring exactly.

[0056] In this embodiment, each layer of sensor bracket 6 is arranged with 9 ranging sensors 14 (9 ranging sensors 14 on the same layer are a group), and each group of ranging sensors is numbered in the same order according to the same position, and the numbers are marked on the transmission line near the sensor. The ranging sensor is a laser ranging sensor with a ranging range of 20-70mm.

[0057] The method for measuring diameter and coaxiality of the present invention comprises the following steps:

[0058] 1. Sensor calibration: Use a standard ring (measured by the metrology department) to calibrate the nine distance measuring sensors 14 on each layer of the sensor bracket on the measuring device. Specifically:

[0059] Taking a certain layer of sensor brackets 8 (set as the first layer in this embodiment) as an example, the straight line where any one of the nine ranging sensors 14 on it emits laser light outward is the positive line of the Y axis, and the straight line passing through point A and perpendicular to the laser light to the right is the positive line of the X axis. With the light source point of the laser sensor as the origin, a coordinate system A(0,0) is established;

[0060] See also Figure 6 , assuming that when the 9 distance measuring sensors are actually installed, the angles with the X axis are θ1, θ2, θ3, θ4, θ5, θ6, θ7, θ8, θ9, (where θ5, θ6 are the angles with the Y axis), and the coordinates of the light source origins of the 9 distance measuring sensors are P A1 (x1,y1),P A2 (x2,y2),P A3 (x3,y3),P A4 (x4,y4),P A5 (x5,y5),P A6 (x6,y6),P A7 (x7 y7), P A8 (x8,y8),P A9 (x9, y9), during calibration, the distances at which the 9 distance measuring sensors emit lasers on the standard circle are a1, a2, ... a9, the radius of the standard circle is r0, and the coordinates of the circle center are O(x, y), then the coordinates of the lasers emitted by the 9 distance measuring sensors on the standard circle are: P A1 (0, a1), P A2 (x2+a2*cosθ2, y2+a2*sinθ2), P A3 (x3+a3*cosθ3, y3+a3*sinθ3), P A4 (x4+a4*cosθ4, y4+a4*sinθ4), P A5 (x5+a5*sinθ5, y5+a5*conθ5), P A6 (x6+a6*sinθ6, y6+a6*cosθ6), P A7 (x7+a7*cosθ7, y7+a7*sinθ7), P A8 (x8+a8*cosθ8, y8+a8*sinθ8), P A9 (x9+a9*cosθ9, y9+a9*sinθ9), the following N equations are obtained by the Pythagorean theorem:

[0061] x 2 +(a1-y) 2 =r0 2

[0062] (x²+a²*cosθ²-x)2 +(y²+a²*sinθ²-y) 2 =r0 2

[0063] (x3+a3*cosθ3-x) 2 +(y3+a3*sinθ3-y) 2 =r0 2

[0064] (x4+a4*cosθ4-x) 2 +(y4+a4*sinθ4-y) 2 =r0 2

[0065] (x5+a5*sinθ5-x) 2 +(y5+a5*cosθ5-y) 2 =r0 2

[0066] (x6+a6*sinθ6-x) 2 +(y6+a6*cosθ6-y) 2 =r0 2

[0067] (x7+a7*cosθ7-x) 2 +(y7+a7*sinθ7-y) 2 =r0 2

[0068] (x8+a8*cosθ8-x) 2 +(y8+a8*sinθ8-y) 2 =r0 2

[0069] (x9+a9*cosθ9-x) 2 +(y9+a9*sinθ9-y) 2 =r0 2

[0070] By moving the standard ring and performing 6 measurements, 9*6=54 equations will be generated. The above equation has 9*4-1=35 unknowns. Adding the coordinates of point A1 (0,0) and the angle of 0, the equation can be solved to obtain the positional relationship between the 9 sensors in this layer. Figure 7 , including: a1, a2, a3, a4, a5, a6, a7, a8, a9, θ2, θ3, θ4, θ5, θ6, θ7, θ8, θ9, P A2 (x2,y2),P A3 (x3,y3),P A4(x4,y4),P A5 (x5,y5),P A6 (x6,y6),P A7 (x7 y7), P A8 (x8,y8),P A9 (x9,y9), and O(x,y);

[0071] Similarly, the relevant parameters of the positional relationship of the 9 distance measuring sensors 14 on the second layer (B), third layer (C) and fourth layer (D) sensor brackets are calculated and saved in the control system software as basic data for subsequent call.

[0072] During the above correction, the data measured by the ranging sensor can be collected multiple times as needed, and the average value can be taken as the final saved data;

[0073] 2. Measurement: The measuring device is vertically hoisted from the top opening of the device under test 6 into the tube of the device under test 6 and hung and fixed. Then, the first measurement is performed to obtain the distances b1, b2, b3, b4, b5, b6, b7, b8, and b9 of the lasers emitted by the nine ranging sensors 14 on each layer of the sensor bracket 8 on the inner wall of the device under test 6. Then, the actual installation angle θ of the corresponding ranging sensor saved in step 1 is calculated. i and the coordinate A of the origin of the ranging sensor light source i (x i ,y i ), calculate and fit the diameter d of the topmost ring of the device under test corresponding to the 9 ranging sensors on the sensor bracket of this layer by the least squares method. i and the center coordinates O i (x, y); thus obtaining the diameters d of the first, second, third and fourth rings in the cylinder of the device under test 6 A d B d C d D , and the center coordinates O A(x,y) , O B(x,y) , O C(x,y) , O D(x,y) , complete the first measurement;

[0074] 3) Coaxiality calibration: After completing the first measurement, the measuring device is rotated 180 degrees around the axial center for a second measurement. The distances b1′, b2′, b3′, b4′, b5′, b6′, b7′, b8′, and b9′ of the nine distance measuring sensors 14 on each layer of the sensor bracket 8 on the inner wall of the device under test 6 are obtained respectively. The method is the same as step 2, and the diameter d of the four layers of the ring of the device under test 6 during the second measurement is obtained. A ′、d B′、d C ′、d D ′, and the coordinates of the center of the circle O A(x,y) 'O B(x,y) 'O C(x,y) 'O D(x,y) ′.

[0075] The center coordinates of the first layer of circular rings measured at a certain height are used as the reference center coordinates for fitting, and the vector relationship between the center coordinates of other circular rings at different heights and the center reference coordinates is calculated for the first and second measurements respectively. In this embodiment, the first layer (uppermost layer) of the circular rings of the measured device 6 is set as the reference circle, and the first layer's reference center coordinates are used for fitting, thereby calculating the center position deviations of the second to fourth layers of measured circular rings relative to the first layer (reference circle). The details are as follows:

[0076] During the first measurement, the vector relationship of the center deviations of the second to fourth ring layers is as follows:

[0077] The second ring O B(x,y) -O A(x,y)

[0078] The third ring O C(x,y) -O A(x,y)

[0079] Fourth Ring O D(x,y) -O A(x,y)

[0080] During the second measurement, the vector relationship of the center deviations of the second to fourth layers of rings is as follows:

[0081] The second ring O B(x,y) ′-O A(x,y) '

[0082] The third ring O C(x,y) ′-O A(x,y) '

[0083] Fourth Ring O D(x,y) ′-O A(x,y) '

[0084] After fitting the actual center of the first layer of rings, the vector relationship of the center deviations of the second to fourth layers of measured rings is as follows, which can be used to determine the coaxiality of the second to fourth layers of rings in the device under test compared to the first layer of rings:

[0085] The second layer (O B(x,y) -O A(x,y) )-(O B(x,y) ′-O A(x,y) ′)

[0086] The third layer (O C(x,y)-O A(x,y) )-(O C(x,y) ′-O A(x,y) ′)

[0087] The fourth layer (O D(x,y) -O A(x,y) )-(O D(x,y) ′-O A(x,y) ′)

[0088] After the data processing is completed, the data will be saved and displayed as a graphical result according to the measurement results. Figure 8 and Figure 9 .

[0089] 4) Also includes compensation when the calibration ambient temperature is different from the measurement ambient temperature:

[0090] Obtain the surface temperature of the calibration ring during calibration and the surface temperature of the device under test during measurement. If there is a temperature difference between the two, compensate according to the following formula:

[0091]

[0092] Where: L is the measured length;

[0093] δ1, δ2 are the linear expansion coefficients of the calibration ring and the device under test respectively

[0094] t1, t2 are the actual temperatures of the calibration ring and the device under test respectively.

[0095] The diameters d of the two measurements i and d i The average value of ′ plus Get the final measurement of the final diameter.

[0096] In this embodiment, the diameter measurement accuracy is ≤0.01 mm, and the coaxiality measurement accuracy is ≤0.025 mm.

[0097] The method of the present invention can greatly shorten the installation and debugging period, replace manual operation, save time and labor, and has high operating efficiency and high measurement accuracy.

Claims

1. A method for measuring the diameter and coaxiality of a cylindrical or conical device, characterized in that: The following steps are included:

1. Sensor calibration: Use the standard ring to calibrate the N distance measuring sensors on each layer of the sensor bracket on the measuring device, and obtain the distance a when the laser emitted by each distance measuring sensor on each layer of the sensor bracket hits the standard ring. i , combined with the standard ring radius r0, the actual installation angle θ of each ranging sensor is obtained by calculation and fitting i and the coordinates A of the origin of the light source of each ranging sensor i (x i ,y i ), and save the data; wherein, the measuring device includes a measuring cylinder, the outer circumference of the measuring cylinder is provided with at least two layers of annular sensor brackets from top to bottom, each layer of sensor brackets is provided with N distance measuring sensors arranged radially along the circumference, N ≥ 3, the top surface of the measuring cylinder is provided with a hanging flange that can be supported on the upper end of the device under test, the hanging flange is also provided with a jacking and rotating assembly for lifting the measuring cylinder and rotating it, the jacking and rotating assembly includes a cover plate and a jacking and rotating bracket located above the hanging flange, the cover plate is fixed to the hanging flange by bolts, the jacking and rotating bracket is provided with a hydraulic cylinder, the piston rod of the hydraulic cylinder is connected to the cover plate, the circumference of the jacking and rotating bracket is evenly provided with a plurality of vertical jacking rods, the lower ends of which pass through the hanging flange, and the lower ends of the jacking rods are provided with bearings that can contact the upper end surface of the device under test; 2. Measurement: The measuring device is vertically hoisted into the tube of the device under test from the top opening of the device under test and fixed in place. Then the first measurement is performed to obtain the distance b between the laser emitted by each ranging sensor on each layer of the sensor bracket and the inner wall of the device under test. i , combined with the actual installation angle θ of the corresponding distance sensor saved in step 1 i Distance sensor light source origin coordinate A i (x i ,y i ), thereby calculating and fitting the diameter d and center coordinates O(x, y) of the cross-section circle of the device under test corresponding to the N distance measuring sensors on the sensor bracket of this layer, and then obtaining the diameter d of the cross-section circle at different heights in the cylinder of the device under test i and the center coordinates O i (x i ,y i ); 3. Coaxiality calibration: After completing the first measurement, rotate the measuring device 180 degrees around the axial center and perform the second measurement. The method is the same as step 2 to obtain the diameter d of the cross-section circle at different heights in the cylinder of the measured device. i ′ and the center coordinates O′(x i ,y i ); According to actual needs, the center coordinates of a certain height section circle are used as the reference center coordinates O0 for fitting, and the vector relationship between the center coordinates of other sections at different heights and the deviations from the reference center coordinates is calculated during the first and second measurements respectively. The vector relationship data obtained from the two measurements are correspondingly subtracted to obtain the center coordinates of the corrected cross-section circles at different heights, thereby obtaining the coaxiality of the device under test.

2. The method for measuring the diameter and coaxiality of a cylindrical or conical device according to claim 1, characterized in that: The calibration method in step 1 is as follows: take the straight line where any one of the N ranging sensors on a certain layer of sensor brackets emits laser light outward as the positive line of the Y axis, take the straight line to the right where the laser light source of the ranging sensor is perpendicular to the positive line of the X axis, and take the center of the position of the light source of the ranging sensor as the center of the circle to establish a rectangular coordinate system Ao; Assume that the angles between the N distance measuring sensors of this layer and the X axis are θ1, θ2, θ3, ..., θn, where θ1 = 90°, and the coordinates of the light source origins of the N distance measuring sensors are A1(x1, y1), A2(x2, y2), ..., A N (x n ,y n ), during calibration, the distances at which the lasers emitted by N ranging sensors hit the standard circle are a1, a2, ...a n , the radius of the standard ring is r0, and the coordinates of the center are O p (x, y), then the coordinates of the lasers emitted by N ranging sensors on the standard ring are: P A1 (0, a1), P A2 (x2+a2*cosθ2, y2+a2*sinθ2),...P AN (x n +a n *cosθ n ,y n +a n *sinθ n ), and the following N equations are obtained by the Pythagorean theorem: x 2 +(a1-y) 2 =r0 2 <h2 style=";text-align:left;direction:ltr">(x2+a2*cosθ2-x)<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +(y2+a2*sinθ2-y)<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> =r0<h2 style=";text-align:left;direction:ltr"> 2 ....... (x n +a n *cosθ n -x) 2 +(y n +a n *sinθ n -y) 2 =r0 2 Using the above method, by adjusting the position of the standard ring, M measurements are performed. Each measurement will form N equations. M measurements will form N*M equations. After M measurements, N*M-1 unknown measurements will be obtained. The coordinates of point A1 are (0,0) and the angle is 0. Because N ≥ 3, when M ≥ 4, the number of equations is greater than the number of unknowns, and the equations can be solved to obtain the positional relationship between the N sensors in this layer, including the actual installation angle θ of each ranging sensor. i and the coordinates A of the origin of the light source of each ranging sensor i (x i ,y i ); Similarly, the relevant parameters of the positional relationship of the N distance measuring sensors on each layer of the sensor bracket are calculated and saved.

3. The method for measuring the diameter and coaxiality of a cylindrical or conical device according to claim 1, characterized in that: It also includes compensation when the correction ambient temperature and the measurement ambient temperature are different: Obtain the surface temperature of the calibration ring during calibration and the surface temperature of the device under test during measurement. If there is a temperature difference between the two, compensate according to the following formula: ▽L=L[δ2(t2-20)-δ1(t1-20)] Where: L is the measured length; δ1, δ2 are the linear expansion coefficients of the calibration ring and the device under test respectively t1, t2 - the actual temperatures of the calibration ring and the device under test respectively The diameters d of the two measurements i and d i The average of the values of ′ plus ▽L gives the final measurement of the final diameter.

4. The method for measuring the diameter and coaxiality of a cylindrical or conical device according to claim 1, wherein: The radial outer peripheral surface of the suspension flange is provided with at least two symmetrical limiting blocks, and the limiting blocks correspond one-to-one to the limiting grooves on the upper end of the device under test.

5. The method for measuring the diameter and coaxiality of a cylindrical or conical device according to claim 1, wherein: A plurality of elastic universal wheels are evenly arranged on the outer peripheral surface of the measuring cylinder.

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