Pose error measurement and compensation device and method for turn-over clamping of large array composite pipe

Abstract

The invention relates to a large array composite pipe turn-over clamping pose error measurement and compensation device and method.The device comprises a probe, a feature point carrier and an internal expansion device, the feature point carrier comprises a device body, the device body is provided with an upper end face and a lower end face, and an inner hole is formed in the device body; the reference features are installed in the composite pipe through an internal expansion device, coordinates of the central axis of the inner hole wall and coordinates of projection of the hole axis on the upper end face are detected through a probe, coordinate data of front feature points under a machine tool coordinate system are obtained, and the coordinates of the central axis of the inner hole wall are x and y coordinates of the feature points; the z coordinate difference of the upper and lower end faces is used for realizing z coordinate detection of the first face and the same reference point after the face is turned over. According to the invention, an accurate reference is provided for double-sided processing of the array composite pipe, the error of the blank is prevented from being fused into the positioning reference, the six-axis positioning deviation of the station relative to the station of the first surface can be measured before the second surface of the array composite pipe is processed, and the relative profile tolerance of the double surfaces after processing is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of array composite tube processing, and in particular to a device and method for measuring and compensating posture errors during flipping and clamping of a large array composite tube. Background Art

[0002] The composite tube array is a honeycomb structure made of two-dimensional densely packed single composite tubes. Figure 1 As shown. Arrayed composite tubes have the advantages of low density, high axial stiffness, good thermal stability, impact resistance and corrosion resistance, and can be used in aerospace, transportation, and automobile fields. During service, the arrayed composite tube acts as a sandwich, and its front and back surfaces are glued together with the upper and lower skins to form a "sandwich" structure. At the same time, its stiffness is relatively strong, and it cannot be fitted with the skin by bending. The front and back surfaces need to be machined to obtain the required size and accuracy. When processing the front and back surfaces of the arrayed composite tube sandwich separately, there is a conversion of the positioning reference. However, in the preparation process of the arrayed composite tube sandwich, the cylindricity of the composite tube unit is poor, resulting in poor relative position accuracy between the units during the array molding process. There is a lack of precise positioning features. Directly using the composite tube unit for positioning will result in errors in the relative position and relative posture of the front and back surfaces of the sandwich. The deviation in posture makes it impossible for the surface shape of the sandwich and the skin to match accurately, resulting in excessive structural internal stress during the gluing and assembly process of the two. The manufactured "sandwich" component cannot meet the service requirements. Summary of the Invention

[0003] In response to the technical problems raised above, a device and method for measuring and compensating posture errors of flip-over clamping of a large array of composite tubes are provided.

[0004] The technical means adopted in the present invention are as follows:

[0005] A device for measuring and compensating posture errors in flip-over clamping of large array composite tubes includes a probe, a feature point carrier, and an internal expansion device. The feature point carrier includes a device body, which has an upper end face and a lower end face. An inner hole is provided inside the device body. The reference feature is installed in the composite tube through the internal expansion device. The coordinates of the center axis of the inner hole wall and the coordinates of the projection of the hole axis on the upper end face are detected by the probe to obtain the coordinate data of the front feature point in the machine tool coordinate system. The coordinates of the center axis of the inner hole wall are the x and y coordinates of the feature point. The z coordinate is determined by the projection of the hole axis on the upper and lower end faces. The average distance h between the upper and lower end faces is measured with a micrometer. i , the difference between the z coordinates of the upper and lower end faces is h i To achieve the z-coordinate detection of the same reference point on the first side and after flipping.

[0006] Furthermore, the internal expansion device includes two open thin-walled rings matched by conical surfaces, an upper pressure plate, a lower pressure plate and a fixed ring, the fixed ring has an opening and side bolts, the inner hole of the fixed ring and the outer cylindrical surface of the device body of the feature point carrier are clearance matched, and the side bolts of the locking fixed ring are used to change the fixed ring, thereby clamping the outer cylindrical surface of the device body to achieve a fastened connection; the fixed ring has two threaded holes symmetrically opened on its end face, the open thin-walled ring is in the middle of the upper and lower pressure plates, and above the fixed ring; the pressure of the upper and lower pressure plates is applied by screws passing through the threaded holes to achieve outward expansion of the open thin-walled ring, tighten the inner wall of the composite tube, and complete the installation of the reference feature block.

[0007] The present invention also discloses a method for measuring and compensating posture errors of a large-scale array composite tube flip clamp, comprising the following steps:

[0008] S1. Use a micrometer to measure the average thickness h of the upper and lower end surfaces of each feature block. i , where i represents the i-th feature block;

[0009] S2. Place each feature block into the array composite tube and clamp the blank under the first station;

[0010] S3, use the machine tool probe to detect the coordinates of the center axis of the inner hole wall and the coordinates of the projection of the hole axis on the upper end surface, and obtain the coordinate data of the front feature point in the machine tool coordinate system (x iM1 ,y iM1 ,z iM1 );

[0011] S4. In the machine tool coordinate system, W0(x 01 ,y 01 ,z 01 ) is the origin, and the workpiece is processed on the first surface at the first station;

[0012] S5, the workpiece is turned over along the x-axis and clamped at the second station. At this time, it is assumed that the workpiece has three-axis angle deviations α, β, and γ around the origin W0, and the coordinates of the origin W0 in the machine tool coordinate system are (x 02 ,y 02 ,z 02 );

[0013] S6. Use the machine tool probe to detect the coordinates of the center axis of the inner hole wall and the coordinates of the projection of the hole axis on the lower end surface, and obtain the coordinate data of the reverse feature point in the machine tool coordinate system (x iM2 ,y iM2 ,z iM2 );

[0014] S7, perform two relative deflection angles α, β, γ of the three axes under the workstation and the coordinates of the second surface origin (x 02 ,y 02 ,z 02)calculate.

[0015] Furthermore, in S7, the specific calculation steps are as follows:

[0016] Assumptions:

[0017] (x 02 ,y 02 ,z 02 )=(x 01 +Δx,-y 01 +Δy,-z 01 +Δz) (8)

[0018] When the workpiece is flipped along the x-axis without angular deviation, the coordinates of the measuring reference carrier become:

[0019] (x iM +Δx,-y iiM +Δy,-z iM +Δz+h i ) (9)

[0020] Therefore, under the condition that the three-axis angle error is a small angle, there is a formula:

[0021]

[0022] Each measurement feature block can obtain three multivariate linear regression equations. Each reference carrier is a sample. For multiple measurement blocks, the required three-axis rotation angle deviation α, β, γ and the coordinates (x 02 ,y 02 ,z 02 ), and fitted by the least squares method using the following fitting equation:

[0023]

[0024] in:

[0025]

[0026] γ,x 02 ,y 02 The fitting calculation uses the result of formula (5):

[0027]

[0028] in:

[0029]

[0030] Where γ is the average of the last two fitting values: γ=(γ x +γ y ) / 2.

[0031] Compared to existing technologies, this invention offers the following advantages: It provides a precise datum for double-sided machining of composite tube arrays, preventing the incorporation of inherent blank errors into the positioning datum. Before machining the second side of the composite tube array, the six-axis positioning deviation of the workstation relative to the first side can be measured, improving the relative contour accuracy of both sides after machining. This method is easy to operate, offers excellent quality and economic benefits, and provides valuable insights for double-sided flipping machining of large components. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0033] Figure 1 Schematic diagram of array composite tube blank.

[0034] Figure 2 This is a schematic diagram of the benchmark feature block of the present invention.

[0035] Figure 3 This is a schematic diagram of the benchmark structure of the benchmark feature block of the present invention.

[0036] Figure 4 Schematic diagram of the feature point extraction method of the present invention.

[0037] Figure 5 This is a flow chart of measuring the relative posture of two surfaces in the present invention. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0041] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0042] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0043] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0044] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0045] like Figures 1 to 5 As shown, the embodiment of the present invention discloses a device and method for measuring and compensating the posture error of the flip-over clamping of a large array composite tube. Before processing the front side of the sandwich structure, a precision reference feature is embedded in the array composite tube unit. After the array composite tube is clamped, the coordinates of these feature points in the machine tool coordinate system are detected by a machine tool probe. When the front side processing is completed, it is flipped over. After the second side is clamped, the coordinates of the same feature point in the machine tool coordinate system are detected again by a machine tool probe. The coordinate relationship of the feature points under these two clamping stations is established using a three-dimensional rigid body transformation matrix method, thereby fitting the two-side relative three-axis rotation angle deviation α, β, γ and the coordinates (x 02 ,y 02 ,z 02 ) and uses the measured six-axis data to compensate for machining the second surface. This method can obtain specific workpiece pose deviation values ​​for both the front and back surfaces. The machined array composite tube sandwich has high relative position accuracy on both the front and back surfaces, which helps improve the qualification rate of sandwich structure products and reduce the repair rate, resulting in significant economic benefits.

[0046] Specifically, the device for measuring and compensating the posture error of the flip-over clamping of a large array composite tube includes a probe, a feature point carrier and an internal expansion device. The feature point carrier includes a device body, the device body has an upper end face and a lower end face, and an inner hole is provided inside the device body. The reference feature is installed in the composite tube through the internal expansion device. The coordinates of the central axis of the inner hole wall and the coordinates of the projection of the hole axis on the upper end face are detected by the probe to obtain the coordinate data of the front feature point in the machine tool coordinate system. The coordinates of the central axis of the inner hole wall are the x and y coordinates of the feature point, and the z coordinate is determined by the projection of the hole axis on the upper and lower end faces. The average distance h between the upper and lower end faces is measured with a micrometer. i , the difference between the z coordinates of the upper and lower end faces is h i To achieve the z-coordinate detection of the same reference point on the first side and after flipping.

[0047] The internal expansion device comprises two open, thin-walled rings with tapered surfaces, an upper and lower pressure plates, and a retaining ring. The retaining ring has an opening and side bolts. The inner hole of the retaining ring and the outer cylindrical surface of the device body, which supports the feature point, are loosely fitted. Tightening the side bolts of the retaining ring deforms the retaining ring, thereby clamping the outer cylindrical surface of the device body to achieve a secure connection. The retaining ring has two threaded holes symmetrically located on its end surface. The open, thin-walled ring is located between the upper and lower pressure plates and above the retaining ring. Screws passing through the threaded holes apply pressure to the upper and lower pressure plates, causing the open, thin-walled ring to expand outward, tightening the inner wall of the composite tube and completing the installation of the reference feature block. The internal expansion device is compact, low in height, and easy to disassemble.

[0048] The present invention also discloses a method for measuring and compensating posture errors of a large-scale array composite tube flip clamp, comprising the following steps:

[0049] S1. Use a micrometer to measure the average thickness h of the upper and lower end surfaces of each feature block. i , where i represents the i-th feature block;

[0050] S2. Place each feature block into the array composite tube and clamp the blank under the first station;

[0051] S3, use the machine tool probe to detect the coordinates of the center axis of the inner hole wall and the coordinates of the projection of the hole axis on the upper end surface, and obtain the coordinate data of the front feature point in the machine tool coordinate system (x iM1 ,y iM1 ,z iM1 );

[0052] S4. In the machine tool coordinate system, W0(x 01 ,y 01 ,z 01 ) is the origin, and the workpiece is processed on the first surface at the first station;

[0053] S5, the workpiece is turned over along the x-axis and clamped at the second station. At this time, it is assumed that the workpiece has three-axis angle deviations α, β, and γ around the origin W0, and the coordinates of the origin W0 in the machine tool coordinate system are (x 02 ,y 02 ,z 02 );

[0054] S6. Use the machine tool probe to detect the coordinates of the center axis of the inner hole wall and the coordinates of the projection of the hole axis on the lower end surface, and obtain the coordinate data of the reverse feature point in the machine tool coordinate system (x iM2 ,y iM2 ,z iM2 );

[0055] S7, perform two relative deflection angles α, β, γ of the three axes under the workstation and the coordinates of the second surface origin (x 02 ,y 02 ,z 02 )calculate.

[0056] Furthermore, in S7, the specific calculation steps are as follows:

[0057] Assumptions:

[0058] (x 02 ,y 02 ,z 02 )=(x 01 +Δx,-y 01 +Δy,-z 01 +Δz) (15)

[0059] When the workpiece is flipped along the x-axis without angular deviation, the coordinates of the measuring reference carrier become:

[0060] (x iM +Δx,-y iM +Δy,-z iM +Δz+h i ) (16)

[0061] Therefore, under the condition that the three-axis angle error is a small angle, there is a formula:

[0062]

[0063] Each measurement feature block can obtain three multivariate linear regression equations. Each reference carrier is a sample. For multiple measurement blocks, the required three-axis rotation angle deviation α, β, γ and the coordinates (x 02 ,y 02 ,z 02 ), and fitted by the least squares method using the following fitting equation:

[0064]

[0065] in:

[0066]

[0067] Where Az and bz are parameters that are convenient for expression in the least squares method. Each row corresponding to them is the observation value extracted from the same measurement feature block. L can be the number 1, indicating the observation value of the first measurement feature block, the second... the i-th... a total of n.

[0068] γ,x 02 ,y 02 The fitting calculation uses the result of formula (5):

[0069]

[0070] in:

[0071]

[0072] Where γ is the average of the last two fitting values: γ=(γ x +γ y ) / 2.

[0073] S8. Compensate the three-axis rotation angle to the CAM machining tool path, set the origin coordinate to the workpiece origin in the machine tool coordinate system, and process the second surface.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for measuring and compensating posture errors during flip-over clamping of large array composite tubes, characterized in that: The method comprises a probe, a feature point carrier and an internal expansion device. The feature point carrier comprises a device body, the device body has an upper end face and a lower end face, an inner hole is provided inside the device body, and the reference feature is installed in the composite tube through the internal expansion device. The coordinates of the central axis of the inner hole wall and the coordinates of the projection of the hole axis on the upper end face are detected by the probe to obtain the coordinate data of the front feature point in the machine tool coordinate system. The coordinates of the central axis of the inner hole wall are the x and y coordinates of the feature point, and the z coordinate is determined by the projection of the hole axis on the upper and lower end faces. The average distance h between the upper and lower end faces is measured with a micrometer. i , the difference between the z coordinates of the upper and lower end faces is h i To achieve the z-coordinate detection of the same reference point on the first side and after flipping.

2. The device for measuring and compensating posture errors of large-scale array composite tubes during flipping and clamping according to claim 1 is characterized in that: The internal expansion device includes two open thin-walled rings matched with conical surfaces, an upper pressure plate, a lower pressure plate and a fixed ring, the fixed ring has an opening and side bolts, the inner hole of the fixed ring and the outer cylindrical surface of the device body of the feature point carrier are clearance matched, and the side bolts of the fixed ring are locked to make the fixed ring deform, and then the outer cylindrical surface of the device body is tightened to achieve a fastened connection; the fixed ring has two threaded holes symmetrically opened on its end face, the open thin-walled ring is in the middle of the upper and lower pressure plates, and above the fixed ring; the pressure of the upper and lower pressure plates is applied by screws passing through the threaded holes to achieve outward expansion of the open thin-walled ring, tighten the inner wall of the composite tube, and complete the installation of the reference feature block.

3. A method for measuring and compensating for posture errors of a device for measuring and compensating posture errors of a large-scale array composite tube flip clamping according to claim 1 or 2, characterized in that: The steps include: S1. Use a micrometer to measure the average thickness h of the upper and lower end surfaces of each feature block. i , where i represents the i-th feature block; S2. Place each feature block into the array composite tube and clamp the blank under the first station; S3, use the machine tool probe to detect the coordinates of the center axis of the inner hole wall and the coordinates of the projection of the hole axis on the upper end surface, and obtain the coordinate data of the front feature point in the machine tool coordinate system (x iM1 ,y iM1 ,z iM1 ); S4. In the machine tool coordinate system, W0(x 01 ,y 01 ,z 01 ) is the origin, and the workpiece is processed on the first surface at the first station; S5, the workpiece is turned over along the x-axis and clamped at the second station. At this time, it is assumed that the workpiece has three-axis angle deviations α, β, and γ around the origin W0, and the coordinates of the origin W0 in the machine tool coordinate system are (x 02 ,y 02 ,z 02 ); S6. Use the machine tool probe to detect the coordinates of the center axis of the inner hole wall and the coordinates of the projection of the hole axis on the lower end surface, and obtain the coordinate data of the reverse feature point in the machine tool coordinate system (x iM2 ,y iM2 ,z iM2 ); S7, perform two relative deflection angles α, β, γ of the three axes under the workstation and the coordinates of the second surface origin (x 02 ,y 02 ,z 02 )calculate.

4. The method according to claim 3, characterized in that In S7, the specific calculation steps are as follows: Assumptions: (x 02 ,y 02 ,z 02 )=(x 01 +Δx,-y 01 +Δy,-z 01 +Δz) (1) When the workpiece is flipped along the x-axis without angular deviation, the coordinates of the measuring reference carrier become: (x iM +Δx,-y iM +Δy,-z iM +Δz+h i ) (2) Therefore, under the condition that the three-axis angle error is a small angle, there is a formula: Each measurement feature block can obtain three multivariate linear regression equations. Each reference carrier is a sample. For multiple measurement blocks, the required three-axis rotation angle deviation α, β, γ and the coordinates (x 02 ,y 02 ,z 02 ), and is fitted by the least squares method using the following fitting equation: in: b z =[z 1M2 +Z1 Z 2M2 +Z2 … with iM2 +Z i … With nM2 +Z n ] T X i =x iM1 –x 01 ,Y i =y iM1 -y 01 ,Z ｉ =Z iM1 -z 01 -h i (5) γ,x 02 ,y 02 The fitting calculation uses the result of formula (5): in: b x =[x 1M2 -X1+βZ1 x 2M2 -X2+βZ2 … x iM2 -X i +βZ i …x nM2 -X n +βZ n ] T b y =[and 1M2 +Y1-αZ1 and 2M2 +Y2-αZ2 … and iM2 +Y i -αZ i … and nM2 +Y n -αZ n ] T (7) Where γ is the average of the last two fitting values: γ=(γ x +γ y ) / 2.

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