Measuring method and measuring device for skin stretch forming

Abstract

The invention discloses a measuring method and a measuring device for skin stretch forming, and belongs to the technical field of skin processing. According to the measurement method for skin stretch forming, online measurement is carried out on the skin in stretch forming production, so that after stretch forming production is completed, the actual readings of the multiple laser distance measuring pieces are recorded, then the actual cross section is fitted according to the theoretical cross section line of the skin on the preset cross section, and the skin stretch forming precision is improved. Therefore, the purpose of measuring the actual cross section line of the skin on the preset cross section can be achieved, the skin stretch-forming state evaluation difficulty is reduced, and the skin stretch-forming precision can be fully evaluated. According to the measuring device for skin stretch forming, the position of the laser distance measuring part can be greatly adjusted by disassembling and assembling the mounting part; by sliding the second sliding rail and the laser distance measuring part, the positions of the laser distance measuring part in the first direction and the second direction can be finely adjusted, and operation is convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of skin processing, in particular to a measuring method and a measuring device for skin stretch forming. BACKGROUND

[0002] Skin is an important component of aircraft sheet metal parts, widely used in aircraft fuselage and wings, which directly constitutes the aerodynamic shape of the aircraft. The skin stretch forming process is the most important process method for manufacturing aircraft skin. Through the relative movement of the die and the drawbench clamp, the metal sheet is plastically deformed under the combined action of tension and bending moment, gradually conforms to the die and obtains the required shape of the part.

[0003] Large curvature skin parts of aircraft, such as leading edges, trailing edges, flaps, ailerons, etc., are usually processed by skin stretch forming machine. Such machine generally clamps metal sheet by jaw, and plastic deformation of metal sheet occurs through the movement of the jaw to conform to the die, realizing the stretch forming of the skin.

[0004] The skin formed by stretch forming will rebound to a certain extent after the jaw is loosened due to elastic deformation and plastic deformation. Therefore, after the skin stretch forming is completed, the skin needs to be measured to evaluate the difference between the stretch formed skin and the theoretical parameters of the skin. However, in the prior art, the skin stretch forming state is difficult to evaluate, and the stretch forming precision is insufficient, which affects the quality of skin stretch forming production. SUMMARY

[0005] The purpose of the present application is to provide a measuring method and a measuring device for skin stretch forming, which reduces the difficulty of evaluating the skin stretch forming state and can fully evaluate the skin stretch forming precision.

[0006] To achieve the above purpose, the following technical solutions are provided:

[0007] The measuring method for skin stretch forming is used to detect the skin formed by stretch forming of a stretch forming die, and the skin includes two clamping ends connected with two stretch forming clamps respectively. The measuring method for skin stretch forming includes the following steps:

[0008] A plurality of laser distance measuring devices are arranged at the same preset cross section below the stretch forming die, and the plurality of laser distance measuring devices are respectively used to measure the distance between the side of the two clamping end faces facing the stretch forming die and the corresponding laser distance measuring device;

[0009] The positions of the plurality of laser distance measuring devices are calibrated;

[0010] mapping the positions of the plurality of laser distance measuring devices obtained by the calibration to a stretch forming numerical model of the skin to determine zero point positions of the plurality of laser distance measuring devices and to determine a theoretical cross-sectional line of the skin on the preset cross-section;

[0011] performing stretch forming to produce the skin;

[0012] after the stretch forming is completed, recording actual readings of the plurality of laser distance measuring devices;

[0013] fitting an actual cross-sectional line of the skin on the preset cross-section according to the plurality of actual readings and the theoretical cross-sectional line.

[0014] As a preferred technical solution of the above-mentioned measurement method for skin stretch forming, the method further comprises the following steps:

[0015] calculating a skin-die gap distribution of the skin on the preset cross-section according to the actual cross-sectional line and the theoretical cross-sectional line; the skin-die gap is a gap between the skin and the stretch forming die.

[0016] As a preferred technical solution of the above-mentioned measurement method for skin stretch forming, the method further comprises the following steps:

[0017] selecting a plurality of target points on the theoretical cross-sectional line and calculating tangent directions and / or curvatures of the plurality of target points;

[0018] calculating skin-die gaps at the plurality of target points according to the actual cross-sectional line and the theoretical cross-sectional line; the skin-die gap is a gap between the skin and the stretch forming die.

[0019] fitting actual longitudinal cross-sectional lines of the skin on longitudinal cross-sections where the plurality of target points are located according to the skin-die gaps at the plurality of target points and a tangent direction continuity and / or a curvature variation minimization principle; the longitudinal cross-sections are perpendicular to the preset cross-section.

[0020] As a preferred technical solution of the above-mentioned measurement method for skin stretch forming, the method further comprises the following steps:

[0021] fitting an actual profile of the skin according to the actual cross-sectional line and the plurality of actual longitudinal cross-sectional lines.

[0022] As a preferred technical solution of the above-mentioned measurement method for skin stretch forming, the method further comprises the following steps:

[0023] calculating a skin-die gap distribution of the skin as a whole and / or a springback amount of the skin according to a theoretical profile of the skin and the actual profile.

[0024] As a preferred technical solution of the measurement method for the stretch forming of the skin, the plurality of target points comprises a plurality of preset target points, and the plurality of preset target points are points on the theoretical cross-section line corresponding to the plurality of laser distance measuring devices.

[0025] As a preferred technical solution of the measurement method for the stretch forming of the skin, the positions of the plurality of laser distance measuring devices are calibrated, including the following steps:

[0026] A calibration reference is provided, and the calibration reference comprises a mold reference provided on the stretch forming mold and / or an external reference provided outside the stretch forming mold.

[0027] The positions of the plurality of laser distance measuring devices are calibrated by simultaneously scanning the calibration reference and the plurality of laser distance measuring devices by a three-dimensional scanner.

[0028] As a preferred technical solution of the measurement method for the stretch forming of the skin, the skin is produced by stretch forming, including the following steps:

[0029] The stretch forming production is started, and the readings of the plurality of laser distance measuring devices are monitored.

[0030] It is determined whether the skin is within the range of the plurality of laser distance measuring devices, if yes, the stretch forming production of the skin is continued, if not, the installation position of the laser distance measuring device exceeding the range is adjusted, and the stretch forming production of the skin is continued until the skin is within the range of the plurality of laser distance measuring devices.

[0031] As a preferred technical solution of the measurement method for the stretch forming of the skin, the actual readings of the plurality of laser distance measuring devices are recorded, including the following steps:

[0032] After the stretch forming production is completed, the actual readings of the plurality of laser distance measuring devices are recorded after the readings of the plurality of laser distance measuring devices are stable.

[0033] In order to achieve the above-mentioned purpose, a measurement device for the stretch forming of the skin is also provided, which is used for the measurement method for the stretch forming of the skin as described in any one of the above, and the measurement device for the stretch forming of the skin comprises a detection module, and the detection module comprises:

[0034] An adjusting mechanism comprises a mounting member, a first sliding rail and a second sliding rail, the mounting member is used for mounting below the stretch forming mold, the first sliding rail is fixedly arranged on the mounting member, and the second sliding rail is slidably arranged on the first sliding rail in a first direction.

[0035] A laser distance measuring piece is slidably arranged on the second slide rail along a second direction, and is used to detect the distance between the skin and the laser distance measuring piece; the first direction is perpendicular to the second direction;

[0036] A locking assembly includes a first locking piece and a second locking piece, the first locking piece is used to lock or unlock the first slide rail and the second slide rail, and the second locking piece is used to lock or unlock the laser distance measuring piece and the second slide rail.

[0037] As a preferred technical solution of the above-mentioned measuring device for skin stretch forming, the skin stretched and formed by the stretch forming die is detected, and the skin includes two clamping ends connected with two stretch forming clamps respectively;

[0038] The detection module is provided with a plurality of detection modules, and the plurality of detection modules are arranged on the same preset cross section below the stretch forming die, and the plurality of detection modules are divided into two detection units, and the laser distance measuring pieces of the two detection units are respectively arranged on one side of the stretch forming die facing the two clamping end faces.

[0039] As a preferred technical solution of the above-mentioned measuring device for skin stretch forming, the lower side of the stretch forming die is provided with a magnetic piece, and the mounting piece is a magnetic suction piece, and the magnetic suction piece is fixedly adsorbed on the magnetic piece.

[0040] Compared with the prior art, the beneficial effects of the present application are:

[0041] The measuring method for skin stretch forming of the present application firstly installs a plurality of laser distance measuring pieces to determine a preset cross section, and takes the preset cross section as the reference for skin measurement and evaluation, and then calibrates the positions of the plurality of laser distance measuring pieces to ensure the reliability of the measurement results of the laser distance measuring pieces; then the skin is measured on line in the stretch forming production, so as to record the actual readings of the plurality of laser distance measuring pieces after the stretch forming production is completed, and then the actual cross section is fitted according to the theoretical cross section line of the skin on the preset cross section, so as to achieve the purpose of measuring the actual cross section line of the skin on the preset cross section, which not only reduces the difficulty of skin stretch forming state evaluation, but also fully evaluates the skin stretch forming precision.

[0042] The measuring device for skin stretch forming of the present application can greatly adjust the positions of the laser distance measuring pieces by disassembling and assembling the mounting piece; and the positions of the laser distance measuring pieces in the first direction and the second direction can be finely adjusted by sliding the second slide rail and the laser distance measuring piece, which is convenient to operate. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The flowchart of the measuring method for skin stretch forming in the embodiments of the present application;

[0044] Figure 2 A detailed flow chart of the measuring method for skin stretch forming in the embodiment of the present application;

[0045] Figure 3 A schematic diagram of the theoretical cross-sectional line and the actual cross-sectional line on the preset cross-section in the embodiment of the present application;

[0046] Figure 4 A schematic diagram of the theoretical longitudinal cross-sectional line and the actual longitudinal cross-sectional line on the longitudinal cross-section in the embodiment of the present application;

[0047] Figure 5 A structural schematic diagram of the measuring device and the stretch forming die for skin stretch forming in the embodiment of the present application;

[0048] Figure 6 A structural schematic diagram of the stretch forming die for skin in the embodiment of the present application;

[0049] Figure 7 A structural schematic diagram of the measuring device for skin stretch forming in the embodiment of the present application;

[0050] Figure 8 A local structural schematic diagram of the measuring device and the skin for skin stretch forming in the embodiment of the present application.

[0051] Reference signs:

[0052] 100, skin; 200, stretch forming die; 300, stretch forming slide rail; 400, preset cross-section; 1, adjusting mechanism; 11, mounting piece; 12, first slide rail; 13, second slide rail; 2, laser distance measuring piece. DETAILED DESCRIPTION

[0053] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0054] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0055] It should be noted that: similar reference signs and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0056] In the description of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings or the orientation or positional relationship commonly used when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation in description and cannot be understood as indicating or implying relative importance. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0057] In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "provided", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0058] In the present application, unless otherwise explicitly specified and limited, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "above" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. "Below", "below" and "below" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0059] The embodiments of the present application are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation on the present application.

[0060] As shown in Figure 1 The present embodiment provides a measurement method for skin stretch forming, for detecting a skin stretched and formed by a stretch forming die, the skin including two clamping ends respectively connected with two stretch clamps.

[0061] The measurement method for skin stretch forming includes the following steps:

[0062] S1, multiple laser distance measuring devices are arranged at the same preset cross section below the stretch-drawing die, and the multiple laser distance measuring devices are respectively used for measuring the distance between the side of the two clamping end faces facing the stretch-drawing die and the corresponding laser distance measuring device.

[0063] In the existing stretch-drawing process, the stretch-drawing die is usually installed on the stretch-drawing slide rail and locked with the stretch-drawing slide rail through a locking device. In the embodiment, multiple laser distance measuring devices can be installed on the stretch-drawing slide rail, so that the laser distance measuring devices do not interfere with each other and are convenient to install. Of course, a mounting rack can also be separately arranged below the stretch-drawing die, and the laser distance measuring devices are installed on the mounting rack. The mounting method of the laser distance measuring devices is not limited in the embodiment.

[0064] It should be noted that the multiple laser distance measuring devices are divided into two groups, each group including multiple laser distance measuring devices, and the directions of the laser emitting heads of the two groups of laser distance measuring devices are different, so that the two clamping end faces facing the stretch-drawing die are measured by the two laser distance measuring devices respectively.

[0065] The type and structure of the laser distance measuring device are not limited in the embodiment, as long as the laser technology can be used for measurement.

[0066] S2, the positions of the multiple laser distance measuring devices are calibrated.

[0067] Optionally, the calibration of the positions of the multiple laser distance measuring devices includes the following steps:

[0068] setting a calibration reference, the calibration reference including a die reference arranged on the stretch-drawing die or an external reference arranged outside the stretch-drawing die;

[0069] simultaneously scanning the calibration reference and the multiple laser distance measuring devices by a three-dimensional scanner to calibrate the positions of the multiple laser distance measuring devices.

[0070] The three-dimensional scanner is used to simultaneously scan the calibration reference and the multiple laser distance measuring devices, so as to ensure the calibration accuracy of the multiple laser distance measuring devices, and thus the reliability of the measurement results is improved.

[0071] It should be noted that the outer surface of the stretch-drawing die is a finished surface. In the embodiment, the die reference arranged on the stretch-drawing die is used as the calibration reference, so that the calibration process is simplified and the measurement efficiency is improved.

[0072] The calibration method of the multiple laser distance measuring devices is not limited in the embodiment, as long as the positions of the multiple laser distance measuring devices can be accurately calibrated.

[0073] S3, the positions of the multiple laser distance measuring devices obtained through the calibration are mapped to the stretch-drawing numerical model of the skin, so as to determine the zero point positions of the multiple laser distance measuring devices and determine the theoretical cross section line of the skin on the preset cross section.

[0074] It should be noted that due to the different cross sections of different positions of the skin, in other words, the shape of the skin at different positions is different, so after the laser ranging device is installed, the position of the laser ranging device needs to be calibrated.

[0075] By mapping the positions of the plurality of laser ranging devices to the stretch forming numerical model of the skin, the readings of the laser ranging devices in the theoretical case can be determined, and the readings are used as the zero point position of the laser ranging device, which is beneficial to improve the accuracy of the measurement results of the laser ranging device.

[0076] S4, performing stretch forming production to make the skin.

[0077] Optionally, performing stretch forming production to make the skin includes the following steps:

[0078] Starting the stretch forming production, collecting and recording the readings of the plurality of laser ranging devices;

[0079] Determining whether the skin is within the range of the plurality of laser ranging devices, if yes, continuing to perform the stretch forming production to make the skin; if no, adjusting the installation position of the laser ranging device that exceeds the range, and until the skin is within the range of the plurality of laser ranging devices, and then continuing to perform the stretch forming production to make the skin.

[0080] Through the above steps, it is ensured that all the laser ranging devices can work normally, and the reliability and accuracy of the measurement results are improved.

[0081] During the stretch forming production, the readings of the plurality of laser ranging devices are monitored in real time, which is beneficial to judge the effectiveness of the measurement results of the laser ranging devices, and provides the possibility for the optimization of the stretch forming process of the skin and the quality monitoring of the skin.

[0082] Exemplarily, when determining whether the skin is within the range of the laser ranging device, if the reading of the laser ranging device stays at the maximum range for a long time, it can be considered that the skin exceeds the range of the laser ranging device.

[0083] S5, after completing the stretch forming production, recording the actual readings of the plurality of laser ranging devices.

[0084] It can be understood that after completing the stretch forming production, the actual readings of the plurality of laser ranging devices are recorded after the readings of the plurality of laser ranging devices are stable, and then the reliability of the measurement results of the plurality of laser ranging devices is ensured.

[0085] S6, fitting the actual cross section line of the skin on the preset cross section according to the plurality of actual readings and the theoretical cross section line.

[0086] Exemplarily, the actual cross-section line of the skin on the preset cross-section can be obtained by interpolating fitting a plurality of actual readings according to a theoretical cross-section line fitting function.

[0087] The measuring method for skin stretch forming in the embodiment firstly installs a plurality of laser distance measuring devices to determine a preset cross-section, and takes the preset cross-section as a reference for skin measurement and evaluation, and then calibrates the positions of the plurality of laser distance measuring devices to ensure the reliability of the measurement results of the laser distance measuring devices; then, the skin is measured on line in the stretch forming production, so as to record the actual readings of the plurality of laser distance measuring devices after the stretch forming production is completed, and then interpolate the actual cross-section on the preset cross-section according to the theoretical cross-section line of the skin on the preset cross-section, so as to achieve the purpose of measuring the actual cross-section line of the skin on the preset cross-section, which not only reduces the difficulty of evaluating the stretch forming state of the skin, but also fully evaluates the stretch forming precision of the skin.

[0088] Optionally, after step S6, the following step is further included:

[0089] According to the actual cross-section line and the theoretical cross-section line, the distribution of the die gap of the skin on the preset cross-section is calculated; the die gap is the gap between the skin and the stretch forming die.

[0090] Since the actual cross-section line and the theoretical cross-section line are located in the same stretch forming die, the distribution of the die gap of the skin on the preset cross-section can be quickly calculated, and the distribution of the die gap can also be directly viewed.

[0091] Optionally, after step S6, the following step is further included:

[0092] A plurality of target points are selected on the theoretical cross-section line, and the tangent direction and / or curvature of the plurality of target points are calculated;

[0093] According to the actual cross-section line and the theoretical cross-section line, the die gap at the plurality of target points is calculated; the die gap is the gap between the skin and the stretch forming die.

[0094] According to the die gap at the plurality of target points, and according to the principle of continuous tangent direction and / or minimum curvature change, the actual longitudinal cross-section line of the skin on the longitudinal cross-section where the plurality of target points are located is fitted; the longitudinal cross-section is perpendicular to the preset cross-section.

[0095] By comparing the actual longitudinal cross-section line of the skin with the theoretical profile, the distribution of the die gap of the skin on the plurality of longitudinal cross-sections produced by the stretch forming production can be directly viewed, which is beneficial to further fully evaluate the stretch forming precision of the skin.

[0096] Optionally, after fitting the actual longitudinal cross-section line of the skin on the longitudinal cross-section where the plurality of target points are located, the following step is further included:

[0097] According to the actual cross-section line and the plurality of actual longitudinal-section lines, the actual profile of the skin is fitted.

[0098] By comparing the actual profile of the skin with the theoretical profile, the overall gap distribution of the skin produced by the stretch forming can be intuitively viewed, which is beneficial to further fully evaluate the stretch forming precision of the skin.

[0099] Optionally, after fitting the actual profile of the skin, the following steps are further included:

[0100] According to the theoretical profile and the actual profile of the skin, the overall gap distribution of the skin and / or the springback amount of the skin is calculated.

[0101] By calculating the overall gap distribution of the skin and / or the springback amount of the skin, the stretch forming precision of the skin and the forming quality of the skin can be accurately evaluated.

[0102] Optionally, the plurality of target points includes a plurality of preset target points, and the plurality of preset target points are points on the theoretical cross-section line corresponding to the plurality of laser distance measuring devices. It should be noted that the plurality of actual readings are the gap distributions at the plurality of preset target points. By the above setting, the calculation process is simplified, and the measurement efficiency is improved.

[0103] Exemplarily, Figure 2 is a detailed flowchart of the measurement method for skin stretch forming provided by the embodiment, and the following will be described in combination with Figure 2 The measurement method for skin stretch forming is described in detail.

[0104] The measurement method for skin stretch forming includes the following steps:

[0105] S101, the plurality of laser distance measuring devices are arranged at the same preset cross-section below the stretch forming die, and the plurality of laser distance measuring devices are respectively used to measure the distance between the two clamping end faces on the side facing the stretch forming die and the corresponding laser distance measuring device.

[0106] S102, the positions of the plurality of laser distance measuring devices are calibrated.

[0107] S103, the positions of the plurality of laser distance measuring devices obtained by the calibration are mapped to the stretch forming numerical model of the skin, so as to determine the zero point positions of the plurality of laser distance measuring devices and determine the theoretical cross-section line of the skin on the preset cross-section.

[0108] Exemplarily, the stretch forming numerical model is established in the upper computer through CAD software.

[0109] S104, the stretch forming production of the skin is started, and the readings of the plurality of laser distance measuring devices are collected and recorded.

[0110] Exemplarily, the plurality of laser distance measuring devices are each communicatively connected to the host computer, and the host computer comprises a data acquisition system, so that the host computer can acquire and record the readings of the plurality of laser distance measuring devices in real time through the data acquisition system. The host computer and the data acquisition system are both prior art, and will not be described here.

[0111] S105, determining whether the skin is within the range of all laser distance measuring devices, if yes, entering S107; if no, entering S106.

[0112] S106, adjusting the installation position of the laser distance measuring device that exceeds the range, and until the skin is within the range of all laser distance measuring devices.

[0113] S107, continuing to perform stretch forming production to manufacture the skin.

[0114] S108, after completing the stretch forming production, waiting for the readings of the plurality of laser distance measuring devices to be stable, and recording the actual readings of the plurality of laser distance measuring devices.

[0115] S109, fitting the actual cross-sectional line of the skin on the preset cross-section according to the plurality of actual readings and the theoretical cross-sectional line.

[0116] As shown in Figure 3 , the solid line is the actual cross-sectional line of the skin on the preset cross-section, and the dashed line is the theoretical cross-sectional line of the skin on the preset cross-section. By comparing the actual cross-sectional line with the theoretical cross-sectional line, the film attachment gap of the skin on the preset cross-section can be evaluated.

[0117] S110, selecting a plurality of preset target points on the theoretical cross-sectional line, and calculating the tangent direction and curvature of the plurality of preset target points. The plurality of preset target points are points on the theoretical cross-sectional line corresponding to the plurality of laser distance measuring devices.

[0118] S111, fitting the actual longitudinal cross-sectional line of the skin on the longitudinal cross-section where the plurality of target points are located according to the plurality of actual readings, and the principle of continuous tangent direction and minimum curvature change; the longitudinal cross-section is perpendicular to the preset cross-section.

[0119] As shown in Figure 4 , the solid line is the actual longitudinal cross-sectional line of the skin on one of the longitudinal cross-sections, and the dashed line is the theoretical longitudinal cross-sectional line of the skin on the longitudinal cross-section. By comparing the actual longitudinal cross-sectional line with the theoretical longitudinal cross-sectional line, the film attachment gap of the skin on the longitudinal cross-section can be evaluated.

[0120] S112, fitting the actual profile of the skin according to the actual cross-sectional line and the plurality of actual longitudinal cross-sectional lines.

[0121] That is, step S112 fits the actual profile of the skin by a full-field interpolation method.

[0122] By fitting the actual contour of the skin, the relationship between the actual forming process deviation of the skin and the movement position deviation of the forming fixture can be evaluated, and then the forming state and forming accuracy of the skin can be fully evaluated.

[0123] S113. Calculate the overall mold gap distribution and the springback of the skin based on the theoretical and actual contours of the skin.

[0124] The measurement method for skin stretch forming of this embodiment takes into account the development demand for high quality and high precision of skin parts, and fully utilizes the structural characteristics of the skin stretch forming when the space of the stretch forming machine is limited and the skin material is complex. It breaks through the situation that the skin stretch forming state is difficult to evaluate and the stretch forming accuracy is insufficient in the traditional production process, and can realize real-time feedback of the skin stretch forming quality during the production process. In other words, it can realize online measurement and feedback, thereby greatly accelerating the process of later optimization and quality evaluation. It can be applied to mass production of skin to improve the current level of digitization and intelligence of skin production.

[0125] The measurement method for skin stretch forming of this embodiment is based on multiple laser ranging devices to measure the deviation between the actual contour and the theoretical contour of the skin at the lower edge of the skin stretching mold, and combines the proposed full-field interpolation method to obtain the overall mold gap distribution of the skin.

[0126] This embodiment also provides a measuring device for skin stretch forming, which is applied to the above-mentioned measuring method for skin stretch forming, can improve the convenience of installation and position adjustment of the laser ranging component, thereby improving the measurement efficiency and the accuracy of the measurement results.

[0127] like Figures 5-8 As shown, the measuring device for skin stretch forming includes a detection module, the detection module includes an adjustment mechanism 1, a laser distance measuring component 2 and a locking assembly, the adjustment mechanism 1 includes a mounting component 11, a first slide rail 12 and a second slide rail 13, the mounting component 11 is used to be installed below the stretching die 200, the first slide rail 12 is fixed to the mounting component 11, and the second slide rail 13 is slidably provided on the first slide rail 12 along a first direction; the laser distance measuring component 2 is slidably provided on the second slide rail 13 along a second direction, and the laser distance measuring component 2 is used to detect the distance between the skin 100 and the laser distance measuring component 2; the first direction is perpendicular to the second direction; the locking assembly includes a first locking component and a second locking component, the first locking component is used to lock or unlock the first slide rail 12 and the second slide rail 13, and the second locking component is used to lock or unlock the laser distance measuring component 2 and the second slide rail 13.

[0128] The measuring device for skin stretch forming of the embodiment can greatly adjust the position of the laser ranging element 2 by disassembling and assembling the mounting element 11, and can finely adjust the position of the laser ranging element 2 in the first direction and the second direction by sliding the second sliding rail 13 and the laser ranging element 2, which is convenient to operate, improves the adaptability of the measuring device for skin stretch forming, ensures that the laser ranging element 2 is in the best measuring position, and improves the accuracy of the measurement result.

[0129] Specifically, the first locking element is a first jack, and the first jack is threadedly connected to the second sliding rail 13. After the second sliding rail 13 is slid to the appropriate position, the first jack is rotated to tightly press the first sliding rail 12 through the first jack, so that the second sliding rail 13 and the first sliding rail 12 are locked. The second locking element is a second jack, and the second jack is threadedly connected to the laser ranging element 2. After the laser ranging element 2 is slid to the appropriate position, the second jack is rotated to tightly press the second sliding rail 13 through the second jack, so that the laser ranging element 2 and the second sliding rail 13 are locked.

[0130] Illustratively, the laser ranging element 2 is a laser sensor, which is simple in structure and easy to assemble.

[0131] Specifically, the detection module is provided with a plurality of detection modules, and the plurality of detection modules are arranged on the same preset cross section 400 below the stretch forming die 200. The plurality of detection modules are divided into two detection units, and the laser ranging elements 2 of the two detection units are respectively directed to one side of the stretch forming die 200.

[0132] Optionally, a magnetic element is arranged below the stretch forming die 200, and the mounting element 11 is a magnetic suction element which is adsorbed and fixed to the magnetic element. The magnetic suction mode is adopted to fix the mounting element 11, which can further improve the convenience of disassembling and assembling the mounting element 11 and improve the measurement efficiency.

[0133] The shape and structure of the magnetic suction element are not limited in the embodiment. Illustratively, the magnetic suction element is a suction disc structure, which is beneficial to improve the adsorption stability.

[0134] Illustratively, the working principle of the measuring device for skin stretch forming of the embodiment is as follows:

[0135] It should be noted that the stretch forming die 200 is usually installed on the stretch forming sliding rail 300 and locked with the stretch forming sliding rail 300 through the locking element. The stretch forming sliding rail 300 is a magnetic element made of ferromagnetic material.

[0136] The magnetic attraction members of the two groups of detection modules are respectively fixed on the two sides of the stretch forming slide rail 300, and the two groups of detection modules are uniformly arranged on the two sides of the stretch forming slide rail 300. Then, according to the theoretical model of the skin 100, the slide laser ranging member 2 and the second slide rail 13 are slid, and the position of the laser ranging member 2 is preliminarily adjusted, that is, the installation of the laser ranging member 2 is completed. Since the installation precision of the magnetic attraction member is limited, this step can ensure the measurement accessibility of the laser ranging member 2, and further ensure that the skin 100 is within the measurement range of all the laser ranging members 2.

[0137] The measurement device for skin stretch forming of the embodiment is connected with the stretch forming slide rail 300 in the mode of magnetic attraction of the mounting member 11, is convenient to disassemble and assemble, and can be matched with different stretch forming dies 200, and further measure different skins 100. By adjusting the positions of the second slide rail 13 and the laser ranging member 2, it can be ensured that the skin 100 can be within the range of all the laser ranging members 2, and the universality is strong, and the measurement precision is high.

[0138] It should be noted that the above are only the preferred embodiments of the present application and the applied technical principles. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A measuring method for skin stretch forming, for testing a skin stretched by a stretching die, wherein the skin comprises two clamping ends connected to two stretching clamps, wherein: The measuring method for skin stretch forming comprises the following steps: Arrange multiple laser distance measuring components at the same preset cross section below the drawing die, wherein the multiple laser distance measuring components are respectively used to measure the distance between the side of the two clamping end surfaces facing the drawing die and the corresponding laser distance measuring components; Calibrate the positions of the plurality of laser ranging components; Mapping the positions of the plurality of laser distance measuring elements obtained by calibration to the tensile digital model of the skin to determine the zero point positions of the plurality of laser distance measuring elements and determine a theoretical cross-sectional line of the skin at the preset cross-sectional area; Performing stretching production to produce the skin; After the drawing production is completed, the actual readings of the plurality of laser distance measuring elements are recorded; According to the plurality of actual readings and the theoretical cross-sectional line, an actual cross-sectional line of the skin at the preset cross-sectional area is fitted.

2. The measuring method for skin stretch forming according to claim 1, characterized in that: The following steps are also included: According to the actual cross-sectional line and the theoretical cross-sectional line, the die gap distribution of the skin on the preset cross-sectional area is calculated; the die gap is the gap between the skin and the stretching die.

3. The measuring method for skin stretch forming according to claim 1, characterized in that: The following steps are also included: Selecting a plurality of target points on the theoretical cross-sectional line, and calculating the tangent vector directions and / or curvatures of the plurality of target points; Calculating mold gaps at a plurality of target points according to the actual cross-sectional line and the theoretical cross-sectional line; The die gap is the gap between the skin and the drawing die; According to the mold gap at the multiple target points and the principle of continuity in the tangent vector direction and / or minimum curvature change, the actual longitudinal section line of the skin on the longitudinal section where the multiple target points are located is fitted; the longitudinal section is perpendicular to the preset cross section.

4. The measuring method for skin stretch forming according to claim 3, characterized in that: The following steps are also included: The actual contour of the skin is fitted according to the actual cross-sectional line and the plurality of actual longitudinal section lines.

5. The measuring method for skin stretch forming according to claim 4, characterized in that: The following steps are also included: According to the theoretical profile and the actual profile of the skin, the overall mold gap distribution of the skin and / or the springback amount of the skin are calculated.

6. The measuring method for skin stretch forming according to claim 3, characterized in that: The plurality of target points include a plurality of preset target points, and the plurality of preset target points are points on the theoretical cross-section line corresponding to the plurality of laser ranging elements.

7. The measuring method for skin stretch forming according to claim 1, characterized in that: Calibration of the positions of the plurality of laser ranging components comprises the following steps: Setting a calibration reference; the calibration reference includes a die reference provided on the drawing die and / or an external reference provided outside the drawing die; The calibration reference and the plurality of laser ranging components are scanned simultaneously by a three-dimensional scanner to calibrate the positions of the plurality of laser ranging components.

8. The measuring method for skin stretch forming according to claim 1, characterized in that: The drawing process to produce the skin includes the following steps: Starting the drawing production and monitoring the readings of the plurality of laser distance measuring elements; Determine whether the skin is within the measuring range of all the laser ranging components. If so, continue to stretch and produce the skin; if not, adjust the installation position of the laser ranging component that exceeds the measuring range, and continue to stretch and produce the skin until the skin is within the measuring range of all the laser ranging components.

9. The measuring method for skin stretch forming according to claim 1, characterized in that: Recording actual readings of a plurality of the laser distance measuring elements comprises the following steps: After the drawing production is completed, wait for the readings of the multiple laser distance measuring components to stabilize, and then record the actual readings of the multiple laser distance measuring components.

10. A measuring device for skin stretch forming, characterized in that: The measuring method for skin stretch forming according to any one of claims 1 to 9, wherein the measuring device for skin stretch forming comprises a detection module, and the detection module comprises: The adjustment mechanism includes a mounting member, a first slide rail, and a second slide rail, wherein the mounting member is used to be mounted below the drawing die, the first slide rail is fixed to the mounting member, and the second slide rail is slidably provided on the first slide rail along a first direction; a laser distance measuring component, the laser distance measuring component being slidably disposed on the second slide rail along a second direction, the laser distance measuring component being used to detect the distance between the skin and the laser distance measuring component; the first direction is perpendicular to the second direction; The locking assembly includes a first locking member and a second locking member, wherein the first locking member is used to lock or unlock the first slide rail and the second slide rail, and the second locking member is used to lock or unlock the laser ranging member and the second slide rail.

11. The measuring device for skin stretch forming according to claim 10, characterized in that: Used for testing a skin formed by stretching through a stretching die, wherein the skin comprises two clamping ends connected to two stretching fixtures respectively; There are multiple detection modules, and the multiple detection modules are arranged in the same preset cross-section below the drawing die. The multiple detection modules are divided into two detection units, and the laser ranging parts of the two detection units are respectively facing the two clamping end faces toward the side of the drawing die.

12. The measuring device for skin stretch forming according to claim 10, characterized in that: A magnetic part is provided below the drawing die, and the mounting part is a magnetic attraction part, which is adsorbed and fixed to the magnetic part.

Images