Rapid measurement system and method for axis of heat insulation pipeline

Abstract

The invention relates to a rapid measurement system and method for the axis of a heat insulation pipeline, and the method comprises the steps: obtaining the feature information of the pipeline through the cooperation of multiple sensors and a movement mechanism, calculating the center of the metal inner wall of the heat insulation pipeline through a provided center searching algorithm, and calculating the center of the metal inner wall of the heat insulation pipeline according to the large-size features and mechanism movement control. Feature information of the heat insulation pipeline is rapidly captured, and the pipeline axis is calculated. The system comprises a laser distance measuring sensor, an eddy current sensing system, a circumferential rotating device, a radial feeding device, an axial feeding device, a high-speed data acquisition system, upper computer software and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical manufacturing of aerospace products, and in particular relates to a rapid measurement system and method for the axis of an insulation pipeline. Background Art

[0002] The insulated pipelines of key components of space launch vehicles have the characteristics of large size, uneven radial distribution of the insulation layer, eccentricity with the pipeline axis, and low axis measurement efficiency. Insulated pipelines with uniform and consistent insulation layer distribution can provide better assembly, insulation, safety, reliability and service performance for key components such as hydrogen-oxygen engines of space launch vehicles. Therefore, how to quickly and accurately capture the spatial coordinate information of the axis of the insulated pipeline has become an important prerequisite for the consistency of the thickness of the service surface processing of the insulated pipeline. The insulated pipeline is composed of an insulation layer (porous non-metal) and a metal pipeline. However, the formation process of the insulation layer makes it impossible to accurately control its outer contour, which makes it difficult to capture the axis of the insulated pipeline after the insulation layer is generated. In addition, during the processing and clamping process of the long-length pipeline, it is bent to a certain extent due to factors such as clamping and deadweight, which increases the difficulty of capturing the axis of the insulated pipeline. The traditional single sensor method is difficult to directly capture the spatial coordinates of the pipeline axis, especially when the outer wall of the metal pipeline is covered with an insulation layer that hinders the measurement of the metal outer wall. For the rapid and accurate measurement of the axis of the insulated pipeline, the existing measurement methods that can penetrate the insulation cover mainly include the penetration method, CT method, ultrasonic method, etc., but different methods have some problems in measurement, such as: (1) The penetration method can penetrate the insulation layer through the needle tip. When the needle tip touches the outer wall of the metal pipeline, the depth of the needle tip penetration is the thickness of the insulation layer. Then, by capturing the insulation cover thickness in different circumferential directions repeatedly, the point coordinates of the outer wall of the metal pipeline are calculated, and then the axis coordinates of the insulated pipeline in this section are inferred by the fitting method. However, this method is difficult to implement in an automated way (because it is difficult to distinguish the penetration and contact thresholds through force sensing in an automated way), and it is generally done manually. However, the manual method is difficult to accurately obtain the circumferential penetration angle (or the spatial coordinate information of the penetration point) and has low efficiency; (2) The industrial CT method can penetrate the insulation layer to obtain the internal three-dimensional information of the insulated pipeline, but its detection efficiency is low, it is difficult to measure the pipeline, and it cannot be integrated with the processing equipment, which makes its integrated industrial application in this regard difficult; (3) The ultrasonic method is difficult to penetrate and measure porous non-metals, which seriously affects the measurement accuracy. Summary of the invention

[0003] The technical problem solved by the present application is: to overcome the deficiencies of the prior art and provide a rapid measurement system and method for the axis of an insulated pipeline, which can be used to isolate the insulation layer to detect the outer wall information of the pipeline and the spatial distribution characteristics of the insulation layer and the pipeline, and to achieve rapid and accurate measurement of the axis of the pipeline, so as to improve the measurement efficiency and accuracy of the axis of the insulated pipeline, thereby ensuring the processing quality of subsequent processing.

[0004] The present invention proposes a rapid measurement system and method for the axis of an insulating pipeline. Through a multi-sensor collaborative method and a pipeline centering algorithm, rapid measurement of the axis of the insulating pipeline is achieved, radial processing accuracy and thickness of the insulating layer are ensured, and the service performance of large key parts in space launch vehicles is improved.

[0005] The technical solutions provided by this application are as follows:

[0006] A rapid measurement system for the axis of an insulated pipeline comprises a measuring spindle, a mover mounting base, a visual measurement system, a laser measurement system, an eddy current measurement system and a radial motion mechanism. The measuring spindle is a cylindrical structure. The mover mounting base rotates around the axis of the measuring spindle and is connected to one end of the measuring spindle. Three radial motion mechanisms are connected to the mover mounting base. The visual measurement system, the laser measurement system and the eddy current measurement system are respectively connected to a radial motion mechanism. The radial motion mechanism is used to drive the visual measurement system, the laser measurement system and the eddy current measurement system to move along the radial direction of the measuring spindle. The measuring spindle is mounted on a moving base, and the moving base is slidably connected to the ground through the motion mechanism. The motion mechanism drives the moving base and the measuring spindle to move axially along the insulated pipeline. The insulated pipeline passes through the middle of the measuring spindle.

[0007] The radial motion mechanism includes a base, a stepper motor, a motion base and a ball screw. The base is fixedly mounted to the mover mounting base, the ball screw is rotatably connected to the base, the stepper motor is used to drive the ball screw to rotate, the motion base is threadedly connected to the ball screw, and the motion base is slidingly connected to the base along the axial direction of the ball screw, and the motion base is used for connection.

[0008] The visual measurement system includes a camera and a lens. When the radial motion mechanism is connected to the visual measurement system, the motion base is connected to the lens through a camera bracket. The laser measurement system includes a laser micrometer bracket and a laser micrometer. When the radial motion mechanism is connected to the laser measurement system, the motion base is connected to the laser micrometer through the laser micrometer bracket. The eddy current measurement system includes an eddy current sensor bracket, an eddy current sensor probe, an eddy current sensor cable and an eddy current sensor power supply. When the radial motion mechanism is connected to the eddy current measurement system, the motion base is connected to the eddy current sensor probe through the eddy current sensor bracket, and the eddy current sensor probe is connected to the eddy current sensor power supply through the eddy current sensor cable.

[0009] A measuring method for a rapid measuring system of an adiabatic pipeline axis, comprising:

[0010] S1: At least one end of the insulated pipeline is fixed to the ground, and the measuring spindle is sleeved outside the insulated pipeline; the insulated pipeline includes a metal pipeline and an insulating layer located outside the metal pipeline;

[0011] S2: A plane perpendicular to the forward direction Z of the measuring spindle is used as the measuring plane, and mutually perpendicular X-axis and Y-axis are established on the measuring plane with the axis center of the measuring spindle as the origin, and two positions where the X-axis intersects with the circumferential direction of the mover mounting base are measuring positions, and the above two measuring positions form a first group of measuring points, and two positions where the Y-axis intersects with the circumferential direction of the mover mounting base are measuring positions, and the above two measuring positions form a second group of measuring points;

[0012] S3: Measure the surface of the outer wall of the insulated pipeline facing the four measuring positions, so that the surface of the outer wall of the insulated pipeline facing the four measuring positions meets the surface measurement requirements, and ensure that the measuring distance of the laser micrometer and the eddy current sensor probe is within the measuring stroke, and the laser micrometer and the eddy current sensor probe do not interfere with the outer wall of the insulated pipeline during the 360° rotation process; in this process, determine the angular positions of the four measuring positions, and record the precise distance from the laser micrometer to the outer surface of the insulation layer and the precise distance from the eddy current sensor probe to the outer surface of the metal pipeline at the four measuring positions;

[0013] S4: according to the precise distance from the laser micrometer to the outer surface of the insulation layer or the precise distance from the eddy current sensor probe to the outer surface of the metal pipe, the measuring spindle is moved so that the axis of the measuring spindle in the measuring plane coincides with the axis of the metal pipe;

[0014] S5: Make the measuring spindle move along the axial direction of the insulated pipeline to perform a scanning process, and record the measurement values ​​of at least 5 positions of the eddy current measurement system and the laser measurement system along the axial direction; after the mover mounting base drives the eddy current measurement system and the laser measurement system to rotate, make the measuring spindle move in the opposite direction along the axial direction of the insulated pipeline, and record the measurement values ​​of at least 5 positions of the eddy current measurement system and the laser measurement system along the axial direction. This process is a reciprocating process, and the rotation angles of the mover mounting base in different reciprocating processes are different, and the measurement data are obtained;

[0015] S6: Filter the measured data to obtain filtered data;

[0016] S7: According to multiple measurement values ​​on the same measuring surface, the axis center of the metal pipe and the axis center of the outer wall of the insulation layer on the measuring surface are obtained, and according to the measurement data of the scanning process, multiple axial axes of the metal pipe and multiple axial axes of the outer wall of the insulation layer are obtained; according to the geometric characteristics of the outer wall of the metal pipe, it is judged whether the insulation pipe is a straight pipe. If it is a straight pipe, according to the multiple axial axes of the metal pipe and the multiple axial axes of the outer wall of the insulation layer, the multiple axes of the metal pipe and the multiple axes of the outer wall of the insulation layer are fitted to obtain the fitting axis of the metal pipe and the fitting axis of the outer wall of the insulation layer.

[0017] The S3 includes: S31: placing the standard pipeline coaxially with the measuring spindle, adjusting the radial position of the lens so that the outer wall of the standard pipeline is within the measuring focal plane of the lens, and the image is clearest. At this time, the distance between the lens and the outer wall of the standard pipeline is C1, the distance between the laser micrometer and the outer wall of the standard pipeline is C2, and the distance between the eddy current sensor probe and the outer wall of the standard pipeline is C3. The positions of the laser micrometer and the eddy current sensor probe are the center positions of their ranges; the radial positions of the lens, laser micrometer and eddy current sensor probe at this time in the measuring spindle are their respective initial zero positions; taking the laser micrometer as an example, 1 / 2 of the measuring range of the laser micrometer is S2, and along the radial position of the measuring spindle, the working distance of the laser micrometer from the outer wall of the standard pipeline is C2±S2;

[0018] S32: a measuring spindle with a radius of d is sleeved outside the heat-insulating pipeline;

[0019] S33: The following measurement steps are performed for each measurement position: the lens is located at the first measurement position, the radial position of the lens is adjusted to make the image clearest, and a photo is taken to obtain image information. At this time, the movement distance of the lens relative to its own initial zero position is Cd. It is judged whether the surface measurement requirements are met according to the image information. If the surface measurement requirements are not met, the movable mounting base is rotated by an angular displacement from the initial measurement position to obtain an updated measurement position, and the outer wall surface of the insulated pipeline facing the updated measurement position is re-measured until the surface measurement requirements are met;

[0020] S34: Then, according to Cd and the radius of the measuring spindle, determine whether interference occurs when the laser micrometer and the eddy current sensor probe rotate to the first measuring position; if interference occurs, radially move the laser micrometer and the eddy current sensor probe until no interference occurs, and adjust the radial position of the laser micrometer and the eddy current sensor probe so that their positions are within their own measurement ranges, measure and obtain the actual measurement distance to the outer wall of the insulated pipeline, and record and adjust the actual detection position of the laser micrometer and the eddy current sensor probe; according to the initial zero position, the actual detection position and the actual measurement distance to the outer wall of the insulated pipeline, obtain the precise distance from the laser micrometer to the outer surface of the insulation layer or the precise distance from the eddy current sensor probe to the outer surface of the metal pipeline;

[0021] S35: Determine the other three measurement positions based on the updated measurement position, and measure the outer wall of the insulated pipeline opposite to the other three measurement positions through steps S33 and S34 for each measurement position. If there is a measurement position that does not meet the surface measurement requirements, continue to obtain the updated measurement position again through the mover mounting base, and detect each measurement step through steps S33 and S34 until all measurement positions meet the surface measurement requirements. The updated measurement points at this time are used as the four measurement positions, and the two radial directions of the four measurement positions are the X-axis and the Y-axis.

[0022] In the step S34, it is determined whether interference occurs when the laser micrometer and the eddy current sensor probe rotate to the first measuring position, including: taking the laser micrometer as an example, calculating Dj=(2d×Cd) 2 -C2, if Dj≥0, interference, otherwise non-interference.

[0023] In the S4, the measuring spindle is moved according to the precise distance from the laser micrometer to the outer surface of the insulation layer or the precise distance from the eddy current sensor probe to the outer surface of the metal pipe, so that the axis center of the measuring spindle in the measuring plane coincides with the axis center of the metal pipe, including: taking the precise distance from the eddy current sensor probe to the outer surface of the metal pipe as an example, the precise distances from the two eddy current sensor probes to the outer surface of the metal pipe measured at the first group of measuring point positions are d1 and d2 respectively, and the precise distances from the two eddy current sensor probes to the outer surface of the metal pipe measured at the second group of measuring point positions are c1 and c2 respectively, so that the measuring spindle is moved by (d2-d1) / 2 along the X-axis direction and by (c2-c1) / 2 along the Y-axis, and the axis center of the measuring spindle in the measuring plane coincides with the axis center of the metal pipe.

[0024] In S5, the reciprocating process is performed more than 2.5 times.

[0025] In S7, the axis of the metal pipe on the same measuring surface is obtained according to multiple measurement values ​​on the same measuring surface, including: on the same measuring surface, the contour formed by multiple measurement positions is approximately an ellipse, the coordinate information of the ellipse in different angular directions is determined, and the major axis orientation, minor axis orientation and intersection of the ellipse are obtained, and the intersection is the axis of the metal pipe in the measuring surface.

[0026] In the above S9, the axis of the metal pipeline on the same measuring surface is obtained according to the multiple measurement values ​​on the same measuring surface, including: the coordinates of the circumferential points on the outer wall of the metal pipeline on the same measuring surface are (x1, y1) to (x5, y5), respectively. Among them, A~F represent the unknown coefficients of the equation;

[0027] The axis is

[0028] In summary, this application at least includes the following beneficial technical effects:

[0029] (1) A rapid measurement system and method for the axis of an insulated pipeline is proposed. Through the multi-sensor coordination method and pipeline centering algorithm, it can be determined whether each sensor interferes with the insulated object at different angular positions, laying the foundation for the correct centering of the subsequent pipeline;

[0030] (2) It can realize rapid measurement of the axis of the insulated pipeline, accurately measure the axis of the metal layer and the insulation layer of the insulated pipeline, and capture the spatial position relationship between the two axes, providing an important basis for the subsequent pipeline insulation layer processing technology and processing trajectory, ensuring the radial processing accuracy and thickness of the insulation layer and other information, and improving the service performance of large key parts in space launch vehicles.

[0031] (3) Improve measurement efficiency and significantly reduce the inconvenience caused by traditional methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the rapid measurement device and system of the present invention;

[0033] Figure 2 It is a schematic diagram of the visual measurement system of the present invention;

[0034] Figure 3 It is a schematic diagram of the laser measurement system of the present invention;

[0035] Figure 4 It is a schematic diagram of the eddy current sensing system of the present invention;

[0036] Figure 5 It is a flow chart of the rapid measurement system and measurement method of the present invention;

[0037] Figure 6 It is a schematic diagram of the axis calculation method of the present invention;

[0038] Figure 7 Schematic diagram of the interference judgment method.

[0039] Description of reference numerals: 1 measuring spindle; 2 visual measuring system; 3 mover mounting base; 4 laser measuring system; 5 eddy current measuring system; 6 radial motion mechanism;

[0040] 3-1 lens; 3-2 camera; 6-1 stepper motor; 6-2 motion base; 6-3 ball screw; 6-4 camera bracket;

[0041] 4-1 laser micrometer; 4-2 laser micrometer bracket;

[0042] 5-1 eddy current sensor probe; 5-2 eddy current sensor cable; 5-3 eddy current sensor power supply; 5-4 eddy current sensor bracket. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] The present application embodiment discloses a system and method for quickly measuring the axis of an insulated pipeline, such as Figure 1 As shown, a rapid measurement system for the axis of an insulated pipeline includes: a measuring spindle 1, a mover mounting base 3, a visual measurement system 2, a laser measurement system 4, an eddy current measurement system 5 and a radial motion mechanism 6.

[0045] The measuring spindle 1 is provided with a mover mounting base 3 which can rotate around the axis of the measuring spindle 1, on which the visual measurement system 2, the laser measurement system 4, and the eddy current measurement system 5 are respectively installed. Among them, three radial motion mechanisms 6 are fixedly mounted on the mover mounting base 3, and the visual measurement system 2, the laser measurement system 4, and the eddy current measurement system 5 are independently mounted on the radial motion mechanism 6. Different measurement systems and their corresponding radial motion mechanisms 6 are connected by screws; the radial motion mechanisms 6 are all mounted on the mover mounting base 3 by screws.

[0046] The radial motion mechanism 6 is composed of a base, a stepper motor 6-1, a motion base 6-2, an encoder, a ball screw 6-3, etc. Among them, the base is fixedly mounted to the mover mounting base 3, the stepper motor 6-1 and the encoder are integrated, or closed-loop control can be selected through other linear encoders. The ball screw 6-3 is rotatably connected to the base, and the stepper motor 6-1 is used to drive the ball screw 6-3 to rotate, and the pitch of the ball screw is 2mm; the camera bracket 6-4 and the motion base 6-2 are used to install the visual measurement system 2, the laser measurement system 4 or the eddy current measurement system 5. A linear guide is set between the base and the motion base 6-2 to guide the linear motion of the motion base 6-2. The visual measurement system 2 includes a camera 3-2 and a lens 3-1, the laser measurement system 4 includes a laser micrometer bracket 4-2 and a laser micrometer 4-1, and the eddy current measurement system 5 includes an eddy current sensor bracket 5-4, an eddy current sensor probe 5-1, an eddy current sensor cable 5-2 and an eddy current sensor power supply 5-3. Figure 2 When the radial motion mechanism 6 is connected to the visual measurement system 2, the motion base 6-2 is connected to the lens 3-1 through the camera bracket 6-4; Figure 3 When the radial motion mechanism 6 is connected to the laser measurement system 4, the motion base 6-2 is connected to the laser micrometer 4-1 through the laser micrometer bracket 4-2; Figure 4 In the figure, when the radial motion mechanism 6 is connected to the eddy current measurement system 5, the motion base 6-2 is connected to the eddy current sensor probe 5-1 through the eddy current sensor bracket 5-4, and the eddy current sensor probe 5-1 is connected to the eddy current sensor power supply 5-3 through the eddy current sensor cable 5-2.

[0047] The measuring spindle 1 is installed on a mobile base, and the mobile base is slidably connected to the ground through a motion mechanism. The motion mechanism drives the mobile base and the measuring spindle 1 to move approximately along the axial direction of the insulated pipeline.

[0048] During measurement, one or both ends of the insulated pipeline are fixed by other devices, and the measuring spindle 1 is sleeved outside the position to be tested of the insulated pipeline. The insulated pipeline includes a metal pipeline and an insulation layer located outside the metal pipeline.

[0049] The rapid measurement system for the axis of the insulated pipeline includes: a multi-axis motion control card, a host computer (PC), a driver (stepping motor, spindle, etc.), a visual measurement system, a laser measurement system, an eddy current measurement system, and different data acquisition cards.

[0050] A quick method for measuring the axis of an insulated pipe includes the following steps:

[0051] like Figure 5 As shown in the figure, the rapid measurement method for the axis of the insulated pipeline mainly includes:

[0052] Step 1: Start preparation, connect each sensor measurement system, and check the accuracy of hardware and communication.

[0053] Step 2: First, based on the visual measurement method, the radial motion mechanism 6 is used to adjust the radial position of the lens 3-1 to make the image clearest, and the angular displacement coordinates and focal length information of the lens 3-1 are recorded. The angular displacement coordinates are determined according to the rotation of the mover mounting base 3, and the focal length information is determined according to the stepping signal of the stepping motor 6-1; at the same time, the visual measurement system 2 collects the image of the outer wall of the insulation pipeline, and visually detects whether there are significant defects on the outer surface of the insulation layer that do not meet the surface measurement requirements based on the image. The visual method includes image processing in the same way as in various countries to extract defect information; or judge the defect information by eye. The measurement requirements for the outer surface of the insulation layer are: surface measurement consistency, no large-size defects, etc.

[0054] Step 3: Determine whether the outer surface of the insulation layer meets the measurement requirements based on the image. If it does, proceed to the next step. If it does not, the mover mounting base 3 is rotated by a small angular displacement (usually 1.2 times the angular displacement corresponding to the camera lens field of view) to redetermine the initial measurement position. This is done until the outer surface of the insulation layer facing the visual measurement system 2 meets the measurement requirements.

[0055] Step 4: When the outer surface of the insulation layer meets the measurement requirements, determine the angular displacement coordinates and focal length information corresponding to the visual measurement system 2;

[0056] Determine the distance between the outer surface contour position of the insulation layer of the insulated pipeline and the visual measurement system 2, and judge whether the measurement distance of the sensor component is within the measurement range based on the radial distance between different sensors that have been calibrated first, and avoid serious interference between the probe component of the measurement system and the outer surface of the insulation layer during the measurement process, thereby damaging the sensor component.

[0057] Step 5: The radial position information of the sensor heads of the laser measurement system and the eddy current measurement system is determined by the radial motion mechanism position, the bracket size and the position of the motion base, and the distance between the probe heads of different sensors is determined. When the distance is not appropriate, it is necessary to send instructions to the motion control card through the host computer, and then the motion control card sends a pulse signal to the driver, and finally the driver controls the stepper motor to rotate and adjust the radial position of the sensor system probe until the lens 3-1, the laser micrometer 4-1 and the eddy current sensor probe head 5-1 are driven to rotate by the passive sub-mounting base 3, and will not interfere with the adiabatic pipeline. The motion mechanism actuating component in the present invention adopts a stepper motor, which can be replaced with other types of motors (such as DC motors, etc.).

[0058] Step 6: After adjusting the position, ensure that the lens 3-1, the laser micrometer 4-1 and the eddy current sensor probe 5-1 do not interfere with the outer surface of the insulation layer, and that the distance between the probe and the outer surface of the insulation layer meets the range of the corresponding sensor system to ensure the normal operation of each sensor system; on this basis, record the relative positions of the laser micrometer 4-1 and the eddy current sensor probe 5-1.

[0059] And perform three-dimensional detection, respectively rotate the laser measurement system and the eddy current measurement system to the angular displacement position of the visual measurement system, and obtain the precise distance from the laser micrometer 4-1 to the outer surface of the insulation layer, and the precise distance from the eddy current sensor probe 5-1 to the outer surface of the metal pipeline;

[0060] Whether interference occurs during the setting, including: Taking the laser micrometer 4-1 as an example, calculate Dj = (2d × Cd) 2 -C2, if Dj ≥ 0, interference, otherwise non-interference;

[0061] Among them, Figure 7 As shown, it is determined that the laser micrometer 4-1 and the eddy current sensor probe 5-1 rotate to the measurement position calibration state: C1-focal length; C2-distance between the laser probe and the outer contour; C3-distance between the eddy current probe and the outer contour. The sensor positions corresponding to C2 and C3 are at the center of their range. Taking the laser probe as an example, assuming its range is ±S2, the sensor working distance corresponding to C2 is C2±S2; the sensor distance difference corresponding to the positions C1 to C3 is d12=C1-C2; d13=C1-C3.

[0062] The actual measurement status: Cd—the radial displacement of the visual camera when the measured surface is in the focal plane of the camera; O2—the distance between the measured surface and the sensor - C2; O3—the distance between the measured surface and the sensor - C3; the judgment of interference when C2 turns to C1: Dj≥0, interference; Dj<0, non-interference; the judgment of whether C2 is within the range when it turns to C1: |Cd|≤|S2|, within the range. When the measured pipeline eccentric position is between sensors C2 and C3, the judgment of C3 is the same.

[0063] Step 7: The upper computer gives instructions to control the mover mounting base 3 to rotate 360° to ensure that the probe at each angle does not interfere with the insulation layer; and the coaxial adjustment operation is performed through the laser measurement system or the eddy current measurement system. Among them, the coaxial adjustment operation using the laser measurement system is based on the outer surface of the insulation layer; the coaxial adjustment operation using the eddy current sensing system is based on the metal outer wall of the insulation pipeline. Taking the eddy current sensing system 5 as an example, the surface perpendicular to the axis of the measuring spindle 1 is the measuring surface, and the two mutually perpendicular directions on the measuring surface are defined as the X axis and the Y axis, and the origin is the axis of the measuring spindle 1. The execution basis of the coaxial adjustment operation is: in the measuring surface, when the insulated pipeline is coaxial with the measuring spindle 1, d1=d2, wherein d1 and d2 respectively represent the distance between the eddy current sensor probe 5-1 and the outer wall of the metal pipeline when the eddy current sensor probe 5-1 is located at the two ends of the X direction on the measuring surface; when the measuring spindle 1 moves along the X direction to the coordinates of the axis of the measuring spindle 1 and the insulated pipeline in the X direction are the same, the distance between the eddy current sensor probe 5-1 and the outer wall of the metal pipeline at the two ends of the X direction on the measuring surface is (d1+d2) / 2. By calculation, it is obtained that the offset of the axis of the insulated pipeline on the measuring surface relative to the axis of the measuring spindle 1 in the X direction should be (d2-d1) / 2. In the same measuring plane, measure once in the X direction and once in the Y direction to obtain the X direction offset and the Y direction offset, and then move the measuring spindle 1 according to the X direction offset and the Y direction offset to make the insulation pipeline coaxial with the measuring spindle 1.

[0064] Step 8: During the axial movement of the measuring spindle 1 along the insulated pipeline, the values ​​of the eddy current measuring system 5 and the laser measuring system 4 are simultaneously recorded to quickly scan the axial direction. The scanning is carried out in an interval point manner, and the selected points are the measuring points divided along the axial direction of the insulated pipeline, and the number of points should be at least greater than 5; the number of reciprocating times should be at least 2.5 times, and the scanning speed should not be less than 10 mm / s.

[0065] Step 9: Filter the measured data. The filtering method is as follows: first, obtain the signal characteristics under steady-state conditions through fast Fourier transform. Taking the sampling interval as 0.5s and the sampling frequency as 1000Hz, the number of filtered data is about 500. The frequency corresponding to the higher frequency division amplitude is obtained through Fourier transform, and the filtering is performed by adding a filter.

[0066] Step 10: Since the installation axis direction of the insulated pipeline is not necessarily perpendicular to the measuring surface of the main axis, the cross-sectional profile measured along the axial direction of the insulated pipeline at the same axial position is approximately an ellipse. By determining the coordinate information of the cross-sectional ellipse in different angular directions, the major axis orientation, minor axis orientation and intersection point (ellipse center) of the ellipse can be obtained. The center of the ellipse at this location is the center of the pipeline section.

[0067] Step 11: After a quick scanning process, the spatial coordinates of the axial center of the pipeline cross section along the axial position of the insulated pipeline are obtained, and the spatial position and coordinates of the pipeline axis are fitted according to the geometric characteristics of the outer wall of the metal pipeline of the insulated pipeline (generally having a function expression or a straight pipeline). When the coefficient of determination is ≥0.95, the measurement requirements are met.

[0068] Example 1

[0069] A specific implementation method for the rapid measurement of the axis of an insulated pipeline includes the following steps:

[0070] Step 1: Prepare to start, turn on the power supply and switch, ensure that each sensor measurement system is connected, and perform self-test on each motion axis. When the self-test is completed and meets the use requirements, prepare to start measurement.

[0071] Step 2: Place the visual measurement system directly above the insulated pipeline, use the radial motion mechanism 6 to adjust the focal length to make the image clearest, and record the angular displacement coordinates and focal length information of the lens 3-1.

[0072] Step 3: When performing three-dimensional detection, the rotation angle of the spindle is set to 120°, and the laser measurement system and the eddy current measurement system are rotated to the angular displacement position of the visual measurement system respectively. The visual measurement system is used to visually inspect the initial corresponding positions of the laser measurement system and the eddy current measurement system. When the surface measurement is consistent and there are no large-size defects, it is considered suitable for measurement.

[0073] Step 4: Determine the angular position corresponding to the visual measurement system, and determine the distance between the outer surface contour of the insulation layer of the insulated pipeline and the visual measurement system through the focal length information of the visual measurement system. According to the radial distance between the different sensors calibrated in priority, adjust the probe of the laser measurement system to 30mm; adjust the eddy current measurement probe to 5mm, and record the relative positions of the eddy current probe and the laser measurement probe.

[0074] Step 5: Rotate the measuring spindle 1 360° in a circumferential direction to ensure that the probes of each sensing system do not interfere with the outer surface of the insulation layer of the insulation pipeline, and ensure that the probes at various angles do not interfere with the insulation layer; and perform centering operations through the eddy current measurement system.

[0075] Step 6: By simultaneously recording the values ​​of the eddy current measurement system and the laser measurement system while the measuring spindle 1 moves along the axial direction of the pipeline, a rapid sweep is performed along the axial direction. The number of sweep points is set to 6; the number of reciprocating times is 3, and the sweep speed is 20 mm / s.

[0076] Step 7: Filter the measured data, where the sampling frequency of the laser micrometer and the sampling frequency of the eddy current sensor head are both set to 1kHz, the sampling interval is 1s, and the interference frequency is 52.5Hz, which is filtered using the notch method.

[0077] Step 8: During the scanning process, the coordinates of the circumferential points on the metal outer wall of the insulated pipeline at the axial position 1 on the axial direction of the insulated pipeline are (x1, y1) to (x5, y5), where the direction of the measurement spindle 1 is the Z direction, and the two mutually perpendicular directions defined on the interface perpendicular to the Z direction are the X direction and the Y direction. Based on the ellipse expression, the following matrix is ​​obtained:

[0078]

[0079] Among them, A~F represent the unknown coefficients of the equation, which are converted into matrix multiplication to obtain:

[0080]

[0081] By solving the above matrix solution, the unknown coefficients A to F can be obtained. Then the expression of the center of the ellipse is:

[0082]

[0083] By calculating the above formula, the axial spatial coordinates (xc1, yc1, z1) of the outer wall of the metal pipe corresponding to the axial position 1 on the measuring surface are obtained.

[0084] Similarly, the axis coordinates of the outer wall of the insulation layer can be obtained.

[0085] Step 9: Taking the straight pipeline as an example, the spatial parameter expression of the metal pipeline axis is obtained by least squares fitting:

[0086] (x,y,z)=(x avg ,y avg ,z avg )+t(a,b,c) (4)

[0087] Among them, the subscript avg represents the coordinates of the center of mass; (a, b, c) is the direction vector of the line; and t is the parameter in the parametric expression.

[0088] Similarly, the fitting axis of the outer wall of the insulation layer is obtained.

[0089] According to the obtained fitting axis of the metal pipe and the fitting axis of the outer wall of the insulation layer, the forming die of the insulation pipe can be adjusted to make the axis of the metal pipe coincide with the axis of the insulation layer. The fitting axis of the metal pipe and the fitting axis of the outer wall of the insulation layer can also be introduced into the processing equipment, so that according to the fitting axis of the metal pipe and the fitting axis of the outer wall of the insulation layer, the outer surface of the insulation layer is further accurately processed to make the axis of the metal pipe coincide with the axis of the insulation layer.

[0090] In view of the problems of difficulty, low efficiency and poor accuracy in measuring the axis of an insulated pipeline, the present invention proposes a system and method for quickly measuring the axis of an insulated pipeline. The system and method can be used to isolate the insulation layer to detect the outer wall information of the pipeline and the spatial distribution characteristics of the insulation layer and the pipeline, and to achieve rapid and accurate measurement of the axis of the pipeline, so as to improve the efficiency and accuracy of measuring the axis of the insulated pipeline, thereby ensuring the quality of subsequent processing. It can be seen from the application cases that the device and method are effective. The invention aims to quickly and accurately capture the spatial coordinate information of the axis of the insulated pipeline, ensure the accuracy and consistency of the insulation layer processing, and improve the service performance of key parts of space launch vehicles.

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

[0092] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A rapid measurement system for the axis of an insulated pipeline, characterized by: The invention comprises a measuring spindle (1), a mover mounting base (3), a visual measuring system (2), a laser measuring system (4), an eddy current measuring system (5) and a radial motion mechanism (6); the measuring spindle (1) is a cylindrical structure; the mover mounting base (3) is connected to one end of the measuring spindle (1) by rotating around the axis of the measuring spindle (1); three radial motion mechanisms (6) are connected to the mover mounting base (3); the visual measuring system (2), the laser measuring system (4) and the eddy current measuring system (5) are each connected to a radial motion mechanism (6); the radial motion mechanism (6) is used to drive the visual measuring system (2), the laser measuring system (4) and the eddy current measuring system (5) to move along the radial direction of the measuring spindle (1); the measuring spindle (1) is mounted on a movable base, the movable base is slidably connected to the ground through the motion mechanism, and the motion mechanism drives the movable base and the measuring spindle (1) to move axially along an insulated pipeline; the insulated pipeline passes through the middle of the measuring spindle (1).

2. A rapid measurement system for the axis of an insulated pipeline according to claim 1, characterized in that: The radial motion mechanism (6) comprises a base, a stepper motor (6-1), a motion base (6-2) and a ball screw (6-3); the base is fixedly mounted on the mover mounting base (3); the ball screw (6-3) is rotatably connected to the base; the stepper motor (6-1) is used to drive the ball screw (6-3) to rotate; the motion base (6-2) is threadedly connected to the ball screw (6-3); the motion base (6-2) and the base are slidably connected along the axial direction of the ball screw (6-3); and the motion base (6-2) is used for connection.

3. A rapid measurement system for the axis of an insulated pipeline according to claim 2, characterized in that: The visual measurement system (2) comprises a camera (3-2) and a lens (3-1); when the radial motion mechanism (6) is connected to the visual measurement system (2), the motion base (6-2) is connected to the lens (3-1) via the camera bracket (6-4); The laser measuring system (4) comprises a laser micrometer bracket (4-2) and a laser micrometer (4-1); when the radial motion mechanism (6) is connected to the laser measuring system (4), the motion base (6-2) is connected to the laser micrometer (4-1) via the laser micrometer bracket (4-2); The eddy current measurement system (5) comprises an eddy current sensor bracket (5-4), an eddy current sensor probe (5-1), an eddy current sensor cable (5-2) and an eddy current sensor power supply (5-3). When the radial motion mechanism (6) is connected to the eddy current measurement system (5), the motion base (6-2) is connected to the eddy current sensor probe (5-1) via the eddy current sensor bracket (5-4), and the eddy current sensor probe (5-1) is connected to the eddy current sensor power supply (5-3) via the eddy current sensor cable (5-2).

4. A method for measuring a fast measuring system for the axis of an insulated pipeline according to any one of claims 1 to 3, characterized in that: include: S1: At least one end of the insulated pipeline is fixed to the ground, and the measuring spindle (1) is sleeved outside the insulated pipeline; the insulated pipeline includes a metal pipeline and an insulating layer located outside the metal pipeline; S2: A plane perpendicular to the forward direction Z of the measuring spindle (1) is used as a measuring plane, and mutually perpendicular X-axis and Y-axis are established on the measuring plane with the axis center of the measuring spindle (1) as the origin, and two positions where the X-axis intersects with the movable mounting base (3) in the circumferential direction are measuring positions, and the above two measuring positions form a first group of measuring points, and two positions where the Y-axis intersects with the movable mounting base (3) in the circumferential direction are measuring positions, and the above two measuring positions form a second group of measuring points; S3: Measure the surface of the outer wall of the insulated pipeline facing the four measuring positions, so that the surface of the outer wall of the insulated pipeline facing the four measuring positions all meet the surface measurement requirements, and ensure that the measurement distance of the laser micrometer (4-1) and the eddy current sensor probe (5-1) is within the measurement range, and the laser micrometer (4-1) and the eddy current sensor probe (5-1) do not interfere with the outer wall of the insulated pipeline during the 360° rotation process; in this process, determine the angular positions of the four measuring positions, and record the precise distance from the laser micrometer (4-1) to the outer surface of the insulation layer and the precise distance from the eddy current sensor probe (5-1) to the outer surface of the metal pipeline at the four measuring positions; S4: moving the measuring spindle (1) according to the precise distance from the laser micrometer (4-1) to the outer surface of the insulation layer or the precise distance from the eddy current sensor probe (5-1) to the outer surface of the metal pipeline, so that the axis of the measuring spindle (1) in the measuring plane coincides with the axis of the metal pipeline; S5: the measuring spindle (1) is moved along the axial direction of the heat-insulating pipeline to perform a scanning process, and the measurement values ​​of the eddy current measurement system (5) and the laser measurement system (4) at at least five positions along the axial direction are recorded; after the mover mounting base (3) drives the eddy current measurement system (5) and the laser measurement system (4) to rotate, the measuring spindle (1) is moved in the opposite direction along the axial direction of the heat-insulating pipeline, and the measurement values ​​of the eddy current measurement system (5) and the laser measurement system (4) at at least five positions along the axial direction are recorded. This process is a reciprocating process, and the rotation angles of the mover mounting base (3) in different reciprocating processes are different, so as to obtain measurement data; S6: Filter the measured data to obtain filtered data; S7: According to multiple measurement values ​​on the same measuring surface, the axis center of the metal pipe and the axis center of the outer wall of the insulation layer on the measuring surface are obtained, and according to the measurement data of the scanning process, multiple axial axes of the metal pipe and multiple axial axes of the outer wall of the insulation layer are obtained; according to the geometric characteristics of the outer wall of the metal pipe, it is judged whether the insulation pipe is a straight pipe. If it is a straight pipe, according to the multiple axial axes of the metal pipe and the multiple axial axes of the outer wall of the insulation layer, the multiple axes of the metal pipe and the multiple axes of the outer wall of the insulation layer are fitted to obtain the fitting axis of the metal pipe and the fitting axis of the outer wall of the insulation layer.

5. The measuring method according to claim 4, characterized in that: The S3 includes: S31: Place the standard pipe coaxially with the measuring spindle (1), adjust the radial position of the lens (3-1) so that the outer wall of the standard pipe is within the measuring focal plane of the lens (3-1), and the image is clearest. At this time, the distance between the lens (3-1) and the outer wall of the standard pipe is C1, the distance between the laser micrometer (4-1) and the outer wall of the standard pipe is C2, and the distance between the eddy current sensor probe (5-1) and the outer wall of the standard pipe is C3. The position of the sensor probe (5-1) is the center position of its measuring range; the radial positions of the lens (3-1), the laser micrometer (4-1) and the eddy current sensor probe (5-1) in the measuring spindle (1) are the initial zero positions of each; taking the laser micrometer (4-1) as an example, 1 / 2 of the measuring range of the laser micrometer (4-1) is S2, and along the radial position of the measuring spindle (1), the working distance of the laser micrometer (4-1) from the outer wall of the standard pipeline is C2±S2; S32: sleeve a measuring spindle (1) having a radius d outside the heat-insulating pipeline; S33: The following measurement steps are performed for each measurement position: the lens (3-1) is located at the first measurement position, the radial position of the lens (3-1) is adjusted to make the image clearest, and a photo is taken to obtain image information. At this time, the movement distance of the lens (3-1) relative to its own initial zero position is Cd. It is determined whether the surface measurement requirements are met based on the image information. If the surface measurement requirements are not met, the movable mounting base (3) is rotated by an angular displacement from the initial measurement position to obtain an updated measurement position, and the outer wall surface of the insulated pipeline facing the updated measurement position is re-measured until the surface measurement requirements are met. S34: Then, based on Cd and the radius of the measuring spindle (1), determine whether interference occurs when the laser micrometer (4-1) and the eddy current sensor probe (5-1) rotate to the first measuring position; if interference occurs, radially move the laser micrometer (4-1) and the eddy current sensor probe (5-1) until no interference occurs, and adjust the radial positions of the laser micrometer (4-1) and the eddy current sensor probe (5-1) so that their positions are within their own measurement ranges, measure and obtain the actual measurement distance to the outer wall of the insulated pipeline, and record and adjust the actual detection positions of the laser micrometer (4-1) and the eddy current sensor probe (5-1); based on the initial zero position, the actual detection position and the actual measurement distance to the outer wall of the insulated pipeline, obtain the precise distance from the laser micrometer (4-1) to the outer surface of the insulation layer or the precise distance from the eddy current sensor probe (5-1) to the outer surface of the metal pipeline; S35: Determine the other three measurement positions based on the updated measurement position, and measure the outer wall of the insulated pipeline opposite to the other three measurement positions through steps S33 and S34 for each measurement position. If there is a measurement position that does not meet the surface measurement requirements, continue to obtain the updated measurement position again through the mover mounting base (3), and detect each measurement step through steps S33 and S34 until all measurement positions meet the surface measurement requirements. The updated measurement points at this time are used as the four measurement positions, and the two radial directions where the four measurement positions are located are the X-axis and the Y-axis.

6. The measuring method according to claim 5, characterized in that: In the above S34, it is determined whether interference occurs when the laser micrometer (4-1) and the eddy current sensor probe (5-1) rotate to the first measurement position, including: taking the laser micrometer (4-1) as an example, calculating Dj=(2d×Cd) 2 -C2, if Dj≥0, interference, otherwise non-interference.

7. The measuring method according to claim 4, characterized in that: In the above S4, the measuring spindle (1) is moved according to the precise distance from the laser micrometer (4-1) to the outer surface of the insulation layer or the precise distance from the eddy current sensor probe (5-1) to the outer surface of the metal pipeline, so that the axis center of the measuring spindle (1) in the measuring plane coincides with the axis center of the metal pipeline, including: taking the moving of the measuring spindle (1) by the precise distance from the eddy current sensor probe (5-1) to the outer surface of the metal pipeline as an example, the precise distances from the two eddy current sensor probes (5-1) to the outer surface of the metal pipeline measured at the first group of measuring point positions are d1 and d2 respectively, and the precise distances from the two eddy current sensor probes (5-1) to the outer surface of the metal pipeline measured at the second group of measuring point positions are c1 and c2 respectively, so that the measuring spindle (1) is moved by (d2-d1) / 2 along the X-axis direction and by (c2-c1) / 2 along the Y-axis, so that the axis center of the measuring spindle (1) in the measuring plane coincides with the axis center of the metal pipeline.

8. The measuring method according to claim 4, characterized in that: In S5, the reciprocating process is performed more than 2.5 times.

9. The measuring method according to claim 4, characterized in that: In S7, the axis of the metal pipe on the same measuring surface is obtained according to multiple measurement values ​​on the same measuring surface, including: on the same measuring surface, the contour formed by multiple measurement positions is approximately an ellipse, the coordinate information of the ellipse in different angular directions is determined, and the major axis orientation, minor axis orientation and intersection of the ellipse are obtained, and the intersection is the axis of the metal pipe in the measuring surface.

10. The measuring method according to claim 4 or 7, characterized in that: In the above S9, the axis of the metal pipeline on the same measuring surface is obtained according to the multiple measurement values ​​on the same measuring surface, including: the coordinates of the circumferential points on the outer wall of the metal pipeline on the same measuring surface are (x1, y1) to (x5, y5), respectively. Among them, A~F represent the unknown coefficients of the equation; The axis is

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