A point positioning device and method on a curved surface

Abstract

This application pertains to static strength and fatigue strength testing of aircraft structures, and specifically relates to a point positioning device and method on a curved surface. Step S1: Obtain a three-dimensional model of the curved surface structure, and based on the three-dimensional model, obtain the coordinates of the modeling target point and the coordinates of at least three modeling reference points; Step S2: Fix the point positioning device on the curved surface structure, and measure the first distance from each ranging sensor to the corresponding real reference point on the curved surface structure; Step S3: Based on the first distance and the relationship between the coordinates of the modeling target point and the coordinates of the modeling reference points, calculate the second distance from each ranging sensor to the real target point; Step S4: Locate the position of the real target point on the curved surface structure using the second distance.

Description

Technical Field

[0001] This application pertains to the static strength and fatigue strength testing of aircraft structures, and specifically relates to a point positioning device and method on a curved surface. Background Technology

[0002] In static strength and fatigue strength tests of aircraft structures, "adhesive tape" is one of the most basic and commonly used loading tools. The "adhesive tape" used in aircraft static strength tests is actually a canvas loading tool that is adhered to the aircraft surface with strong adhesive to withstand tensile forces. Before applying the "adhesive tape," the placement point on the aircraft surface needs to be confirmed.

[0003] For surfaces with low curvature or low curvature in one direction, positioning points can be determined using a ruler. However, for surfaces like a cockpit canopy with high curvature in all directions, using a ruler to locate the adhesive tape is generally difficult. The traditional method is to subdivide the surface into multiple contour lines, with nodes distributed along these lines. These nodes divide the surface into multiple measurement blocks, and the adhesive tape's placement is determined step-by-step by measuring the side length of each block. Figure 1 As shown. The more measurement blocks this method subdivides, the more accurate the measurement becomes, but it also means a huge number of points and lines need to be measured manually, which is not only inefficient but also has low accuracy in practical applications. Summary of the Invention

[0004] To address the aforementioned problems, this application provides a point positioning device on a large curvature surface, comprising:

[0005] A fixed bracket is provided, on which at least three distance sensors are mounted, and the distance sensors are not in a straight line.

[0006] The support leg has one end connected to a fixed bracket and the other end used for mounting and fixing; the support leg enables the ranging sensor to be at a preset height from the aircraft surface.

[0007] Preferably, the ranging sensor includes a wire displacement sensor and a laser sensor.

[0008] Preferably, the fixed bracket has at least three slide rails with intersecting axes, and a slider is provided on the slide rail, with the ranging sensor mounted on the slider.

[0009] Preferably, the slider has a threaded through hole, and a bolt is screwed into the threaded through hole. Screwing in the bolt causes the end of the bolt to abut against the slide rail, thereby positioning the slider.

[0010] Preferably, the slide rail has a scale that indicates the position of the slider.

[0011] Preferably, the number of support legs includes at least three, the support legs are hinged to the fixed bracket, the support legs have rotational freedom about the fixed bracket, and the hinge point between the support leg and the fixed bracket has a positioning pin, the pin locking the support leg at a preset angle with the fixed bracket.

[0012] A point positioning method on a large curvature surface, using the aforementioned point positioning device on a large curvature surface, step S1: obtaining a three-dimensional model of the surface structure, and obtaining the coordinates of the modeling target point and the coordinates of at least three modeling reference points based on the three-dimensional model;

[0013] Step S2: Fix the point positioning device on the curved surface structure, and measure the first distance from each distance sensor to each real reference point corresponding to the modeling reference point on the curved surface structure;

[0014] Step S3: Based on the first distance and the relationship between the coordinates of the modeling target point and the coordinates of the modeling reference point, calculate the second distance from each ranging sensor to the real target point;

[0015] Step S4: Locate the position of the actual target point on the curved surface structure using the second distance.

[0016] Preferably, step S3 can also calculate the second distance by the following method: calculating the coordinates of each ranging sensor based on the first distance, and calculating the second distance based on the coordinates of each ranging sensor and the coordinates of the modeling target point.

[0017] Preferably, the method for locating the position of the actual target point on the curved surface structure using the second distance is as follows:

[0018] Draw a positioning sphere with the distance sensor as the center and the second distance corresponding to the distance sensor as the radius. Obtain the intersection circle between the positioning sphere corresponding to each distance sensor and the surface of the curved structure. Obtain the intersection point of the intersection circle, and the intersection point is the real target point.

[0019] This application design adopts a wire measurement method, which consists of three wire displacement sensors located in space. The three wire displacement sensors are spaced apart and their positions are relatively fixed. The ends of the wires of the three wire displacement sensors are fixed together. For any point in space, the distance between the three wires has a unique value. The fixed value of the three distances corresponds to a unique point in space, which can accurately measure the point on the curvature surface. Attached Figure Description

[0020] Figure 1 This is the basic principle of the positioning device on the curved surface according to a preferred embodiment of this application;

[0021] Figure 2This is a schematic diagram of the three-point positioning operation of a point positioning device on a curved surface according to a preferred embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0023] This application provides a point positioning device on a large curvature surface, comprising: a fixed bracket on which at least three ranging sensors are mounted, the ranging sensors not being on the same straight line; a support leg, one end of which is connected to the fixed bracket and the other end is used to fix the device to the surface of an aircraft or the ground, for fixing the relative distance between the device and the aircraft, so that the two are in the same coordinate system; the support leg enables the ranging sensors to have a preset height with the aircraft surface, wherein the ranging sensors include a wire displacement sensor and a laser sensor, the fixed bracket has at least three slide rails with intersecting axes, and sliders are provided on the slide rails, the ranging sensors being mounted on the sliders.

[0024] Preferably, the slider has a threaded through hole, and a bolt is screwed into the threaded through hole. Screwing in the bolt causes the end of the bolt to abut against the slide rail, thereby positioning the slider.

[0025] Preferably, the slide rail has a scale that indicates the position of the slider.

[0026] Preferably, the number of support legs includes at least three, the support legs are hinged to the fixed bracket, the support legs have rotational freedom about the fixed bracket, and the hinge point between the support leg and the fixed bracket has a positioning pin, the pin locking the support leg at a preset angle with the fixed bracket.

[0027] The function of a draw-wire displacement sensor is to convert mechanical motion into an electrical signal that can be measured, recorded, or transmitted. The sensor consists of a stretchable stainless steel rope wound around a threaded hub, which is connected to a precision rotary sensor. This sensor can be an incremental encoder, an absolute (independent) encoder, a hybrid or conductive plastic rotary potentiometer, a synchronizer, or a resolver. Operationally, the draw-wire displacement sensor is mounted in a fixed position, with the rope attached to the moving object. The linear motion of the rope is aligned with the axis of motion of the moving object. During motion, the rope extends and contracts. An internal spring ensures that the rope tension remains constant. The threaded hub drives the precision rotary sensor to rotate, outputting an electrical signal proportional to the distance the rope has moved. Measuring the output signal allows the determination of the displacement, direction, or speed of the moving object.

[0028] A method for locating points on a surface with high curvature, the principle of which is as follows: Figures 1-2 As shown, the point positioning device on the large curvature surface is specifically implemented as follows: the point positioning device has a pull wire sensor A, a pull wire sensor B and a pull wire sensor C. The three sensors have a fixed distance and their relative positions remain unchanged. Step S1: Obtain the three-dimensional model of the curved surface structure, and obtain the coordinates of the modeling target point and the coordinates of the three modeling reference points based on the three-dimensional model, as shown in the figure: first reference point 1, second reference point 2 and third reference point 3.

[0029] Step S2: Fix the point positioning device on the curved surface structure, and measure the first distances from the pull-wire sensor A, pull-wire sensor B, and pull-wire sensor C to the corresponding real reference points on the curved surface structure. The first distances include: distance L1, distance L2, and distance L3. The ends of the pull ropes of the three pull-wire displacement sensors are fixed together. For any point in space, the corresponding three pull-wire distances L1, L2, and L3 have unique values. Conversely, if the three distances L1, L2, and L3 are set to fixed values, they correspond to a unique point in space.

[0030] Step S3: Based on the first distance and the relationship between the coordinates of the modeling target point and the coordinates of the modeling reference point, calculate the second distance from each ranging sensor to the real target point;

[0031] Step S4: Locate the position of the actual target point on the curved structure using the second distance. Specifically, pull the cables of the three displacement sensors to the calculated distances. The resulting points are the positions of the actual target points to be drawn. The method for locating the position of the actual target point on the curved structure using the second distance is as follows:

[0032] Draw a positioning sphere with the distance sensor as the center and the second distance corresponding to the distance sensor as the radius. Obtain the intersection circle between the positioning sphere corresponding to each distance sensor and the surface of the curved structure. Obtain the intersection point of the intersection circle, and the intersection point is the real target point.

[0033] Preferably, step S3 can also calculate the second distance by the following method: based on the first distance, the coordinates of each ranging sensor are calculated using the spatial distance formula, and the second distance is calculated based on the coordinates of each ranging sensor and the coordinates of the modeling target point.

[0034] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for locating points on a surface with high curvature, characterized in that, A point positioning device is used on a surface with high curvature, the point positioning device comprising: A fixed bracket is provided, on which at least three distance sensors are mounted, and the distance sensors are not in a straight line. A support leg, one end of which is connected to a fixed bracket, and the other end for mounting and fixing; the support leg ensures that the ranging sensor is at a preset height above the aircraft surface; the fixed bracket has at least three intersecting slide rails, on which sliders are mounted, and the ranging sensor is mounted on the sliders; the method includes: Step S1: Obtain the 3D model of the curved surface structure, and obtain the coordinates of the modeling target point and the coordinates of at least three modeling reference points based on the 3D model; Step S2: Fix the point positioning device on the curved surface structure, and measure the first distance from each distance sensor to the corresponding real reference point on the curved surface structure; Step S3: Based on the first distance and the relationship between the coordinates of the modeling target point and the coordinates of the modeling reference point, calculate the second distance from each ranging sensor to the real target point; Step S4: Locate the position of the actual target point on the curved surface structure using the second distance.

2. The point positioning method on a large curvature surface as described in claim 1, characterized in that, Distance sensors include wire displacement sensors or laser sensors.

3. The point positioning method on a large curvature surface as described in claim 1, characterized in that, The slider has a threaded through hole, and a bolt is screwed into the threaded through hole. Screwing in the bolt causes the end of the bolt to abut against the slide rail, thereby positioning the slider.

4. The point positioning method on a large curvature surface as described in claim 3, characterized in that, The slide rail has a scale that indicates the position of the slider.

5. The point positioning method on a large curvature surface as described in claim 1, characterized in that, The number of support legs is at least three. The support legs are hinged to the fixed bracket. The support legs have rotational freedom about the fixed bracket. The hinge point between the support legs and the fixed bracket has a positioning pin. The pin locks the support legs at a preset angle with the fixed bracket.

6. The point positioning method on a large curvature surface as described in claim 1, characterized in that, Step S3 can also calculate the second distance by the following method: calculating the coordinates of each ranging sensor based on the first distance, and calculating the second distance based on the coordinates of each ranging sensor and the coordinates of the modeling target point.

7. The point positioning method on a large curvature surface as described in claim 1, characterized in that, The method for locating the position of the actual target point on the curved structure using the second distance includes: Draw a positioning sphere with the distance sensor as the center and the second distance corresponding to the distance sensor as the radius. Obtain the intersection circle between the positioning sphere corresponding to each distance sensor and the surface of the curved structure. Obtain the intersection point of the intersection circle, and the intersection point is the real target point.

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