Movable type mass center measuring device

Abstract

The utility model relates to the field of space flight and aviation, in particular to a movable centroid measuring device which comprises four independent movable measuring tools which are used for being distributed to a measuring site and located at the four vertexes of a rectangle. Wherein each measuring tool comprises a lower support frame, four pressure sensors, an upper support frame and a set of switching tool; the upper surface and the lower surface of the lower supporting frame are horizontal, and the four pressure sensors are placed on the upper surface of the lower supporting frame. The upper surface and the lower surface of the upper supporting frame are horizontal, and the lower surface of the upper supporting frame makes contact with the upper ends of the four sensors. The lower end of the switching tool is movably connected to the upper surface of the upper supporting frame, and the upper end of the switching tool is used for being connected with a tested piece. The mass center measuring device can be changed from a fixed state to a movable state, meanwhile, the occupied area is small, the measuring range of the mass center measuring device is widened, and the cost of rocket mass center measurement is reduced.

Description

Technical Field

[0001] This application relates to the field of aerospace, and more particularly to a mobile centroid measurement device. Background Technology

[0002] For launch vehicles, the axial and lateral center of mass positions are crucial for attitude control design. More accurate center of mass position parameters can effectively reduce the envelope of control parameters, decrease engine sway angle, and further enhance rocket payload capacity. The principle of a center of mass measurement device is to use multi-point support and, based on force and torque balance, calculate the distance from the center of mass of the measured component to the support points. This distance is then converted into three parameters relative to a reference coordinate system of the measured component, which constitute the center of mass of the measured component.

[0003] Currently, most of the equipment used for measuring the center of mass position of rocket sections and sub-stages is fixed. First, the equipment occupies a large area and has high site requirements; second, the equipment cannot be moved, and the measured part needs to be transported to the measurement site for measurement, which is time-consuming, labor-intensive, and costly; third, it has poor adaptability and can only measure the measured part within a certain range of length, diameter, and weight.

[0004] Therefore, how to make the center of mass measurement device occupy a smaller area, increase the measurement range of the center of mass measurement device, and reduce the cost of rocket center of mass measurement is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] This application provides a mobile center of mass measurement device, which reduces the footprint of the center of mass measurement device, increases the measurement range of the center of mass measurement device, and reduces the cost of rocket center of mass measurement.

[0006] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0007] A mobile centroid measuring device includes four independent movable measuring fixtures, which are distributed at the four vertices of a rectangle in a measuring area. Each measuring fixture includes a lower support frame, four pressure sensors, an upper support frame, and a set of adapter fixtures. The upper and lower surfaces of the lower support frame are horizontal, and the four pressure sensors are placed on the upper surface of the lower support frame. The upper and lower surfaces of the upper support frame are horizontal, and the lower surface of the upper support frame contacts the upper ends of the four sensors. The lower end of the adapter fixture is movably connected to the upper surface of the upper support frame, and the upper end of the adapter fixture is used to connect to the workpiece being measured.

[0008] In the mobile centroid measuring device described above, preferably, the lower support frame is cuboid in shape with its length direction being vertical; the upper support frame is frustum in shape with its height direction being vertical.

[0009] The mobile center of mass measuring device as claimed in any one of the preceding claims, wherein preferably, the lower support frame is a cuboid truss structure, and the upper support frame is a quadrangular prism truss structure.

[0010] The mobile center of mass measuring device as claimed in any one of the preceding claims, wherein preferably, the lower support frame comprises a square upper support plate, a square lower support plate and four support columns, upper ends of the four support columns are fixed to a lower surface of the square upper support plate and are located near four vertices of the square upper support plate respectively, lower ends of the four support columns are fixed to an upper surface of the square lower support plate and are located near four vertices of the square lower support plate respectively, and the four support columns extend vertically to form the cuboid truss structure.

[0011] The mobile center of mass measuring device as claimed in any one of the preceding claims, wherein preferably, four limiting frames are fixedly connected to an upper surface of the lower support frame, each pressure sensor is located in one limiting frame and an inner surface of the limiting frame is in contact with an outer surface of the pressure sensor, and a height of the limiting frame is lower than a height of the pressure sensor.

[0012] The mobile center of mass measuring device as claimed in any one of the preceding claims, wherein preferably, the upper support frame comprises a square upper support plate, a square lower support plate and four support columns, upper ends of the four support columns are fixed to a lower surface of the square upper support plate and are located near four vertices of the square upper support plate respectively, lower ends of the four support columns are fixed to an upper surface of the square lower support plate and are located near four vertices of the square lower support plate respectively, and the four support columns are inclined outward gradually from top to bottom to form the quadrangular prism truss structure.

[0013] The mobile center of mass measuring device as claimed in any one of the preceding claims, wherein preferably, a top end of each support column of the upper support frame is fixedly connected to a bottom end of one hydraulic cylinder, a top end of each hydraulic cylinder is fixedly connected to a lower surface of the square upper support plate of the upper support frame, and each hydraulic cylinder extends vertically.

[0014] The mobile center of mass measuring device as claimed in any one of the preceding claims, wherein preferably, the adapter tool has a connecting hole penetrating through an upper surface and a lower surface, the square upper support plate of the upper support frame has a connecting hole penetrating through an upper surface and a lower surface at a middle position, and a bolt passes through the connecting hole of the adapter tool and the connecting hole of the square upper support plate of the upper support frame to movably connect the adapter tool to the upper surface of the upper support frame.

[0015] The mobile center of mass measuring device as claimed in any one of the preceding claims, wherein preferably, an upper end surface of the adapter tool has a downwardly recessed groove, and the groove penetrates through two opposite side surfaces.

[0016] Relative to the above background art, the mobile center of mass measuring device has four independent measuring tools, there is no connection between the measuring tools, and the measuring tools do not need to be fixed to the ground or other platforms, so that the center of mass measuring device has a smaller floor area, and also makes the transfer convenient, and reduces the cost of rocket center of mass measurement. In addition, the pressure sensor can be selected according to the weight of the measured piece, and the measuring tool can also be transformed according to the size of the measured piece, so that it can also be applied to the center of mass measurement of different measured pieces, so that the range of the center of mass measurement is wider, and the cost of the rocket center of mass measurement is also reduced. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0018] Figure 1 is a schematic diagram of a mobile center of mass measuring tool provided by the embodiment of the present application;

[0019] Figure 2 is a schematic diagram of a mobile center of mass measuring device provided by the embodiment of the present application;

[0020] Figure 3 is a schematic diagram of a mobile center of mass measuring device provided by the embodiment of the present application. DETAILED DESCRIPTION

[0021] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. In addition, spatial relationship terms such as "upper", "lower", "left", "right", "front", "back", etc. are used to make the description convenient, to explain the positional relationship between two components. The embodiments described below by referring to the drawings are exemplary, only for explaining the present application, and cannot be explained as a limitation to the present application.

[0022] As Figure 1 and Figure 2 shown, the present application provides a mobile center of mass measuring device, comprising: four independent movable measuring tools 100, and the four measuring tools 100 are used to be distributed to the measuring site, and are located at the four vertices of a rectangle; each measuring tool 100 comprises: a lower support frame 111, four pressure sensors 112, an upper support frame 113 and a set of adapter tools 114.

[0023] The lower surface of the lower support frame 111 is horizontal for placing on the ground; the upper surface of the lower support frame 111 is horizontal for placing the four pressure sensors 112. Optionally, the lower support frame 111 is cuboid-shaped, and the long direction of the lower support frame 111 is vertical. Further optionally, the lower support frame 111 is a long cuboid truss structure, so that the weight of the lower support frame 111 is lighter, which is conducive to the transfer of the lower support frame 111. Yet further optionally, the lower support frame 111 comprises a square upper support plate 1111, a square lower support plate 1112, and four support columns 1113; the upper ends of the four support columns 1113 are fixed to the lower surface of the square upper support plate 1111 and are respectively located near the four vertices of the square upper support plate 1111; the lower ends of the four support columns 1113 are fixed to the upper surface of the square lower support plate 1112 and are respectively located near the four vertices of the square lower support plate 1111; and the four support columns 1113 extend vertically, thereby forming a long cuboid truss structure.

[0024] The four pressure sensors 112 are placed on the upper surface of the lower support frame 111, and the four pressure sensors 112 are distributed in a square shape, and the pressure sensors 112 can be replaced according to the weight of the measured object 200. Optionally, the four pressure sensors 112 are respectively distributed near the four vertices of the square upper support plate 1111. Further optionally, in order to ensure that the positions of the four pressure sensors 112 on the upper surface of the lower support frame 111 do not move, four limiting frames (not shown in the figure) are fixedly connected to the upper surface of the lower support frame 111 for accommodating the pressure sensors 112, and after the pressure sensors 112 are placed in the limiting frames, the inner surfaces of the limiting frames are in contact with the outer surfaces of the pressure sensors 112, so that the positions of the pressure sensors 112 can be prevented from moving; and the heights of the limiting frames are lower than the heights of the pressure sensors 112, so that the pressure sensors 112 can be ensured to be in contact with the lower surface of the upper support frame 113. Yet further optionally, the four limiting frames are respectively located near the four vertices of the square upper support plate 1111.

[0025] The lower surface of the upper support frame 113 is horizontal, used to contact the upper ends of the four sensors 112; the upper surface of the upper support frame 113 is horizontal, used to movably connect with the adapter tool 114; and the upper support frame 113 can be telescopic along the vertical direction. Optionally, the upper support frame 113 is in the shape of a quadrangular pyramid, and the high direction thereof is the vertical direction. Further optionally, the upper support frame 113 is in the structure of a quadrangular pyramid truss, so that the weight of the upper support frame 113 is lighter, which is beneficial to the transfer of the upper support frame 113. Yet further optionally, the upper support frame 113 comprises a square upper support plate 1131, a square lower support plate 1132 and four support columns 1133; the upper ends of the four support columns 1133 are fixed to the lower surface of the square upper support plate 1131 and are respectively located near the four vertices of the square upper support plate 1131; the lower ends of the four support columns 1133 are fixed to the upper surface of the square lower support plate 1132 and are respectively located near the four vertices of the square lower support plate 1131; and the four support columns 1133 are gradually inclined outward from top to bottom, so as to form the structure of a quadrangular pyramid truss. Still optionally, the top end of each support column 1133 of the upper support frame 113 is fixedly connected with the bottom end of a hydraulic cylinder, the top end of each hydraulic cylinder is fixedly connected with the lower surface of the square upper support plate 1131, and each hydraulic cylinder extends vertically, so as to ensure that the upper support frame 113 can be telescopic along the vertical direction.

[0026] The lower end of the adapter tool 114 is movably connected to the upper surface of the upper support frame 113, and the downward orthogonal projection of the adapter tool 114 is located in the middle of the part surrounded by the four pressure sensors 112; the upper end of the adapter tool 114 is used to connect with the measured piece 200, and the adapter tool 114 can be customized according to the measured piece 200. Optionally, the adapter tool 114 is located in the middle position of the square upper support plate 1131 of the upper support frame 113. Further optionally, the lower end of the adapter tool 114 has a connection hole penetrating through the upper and lower parts thereof, and the middle position of the square upper support plate 1131 of the upper support frame 113 has a connection hole penetrating through the upper and lower parts thereof; a bolt passes through the connection hole of the adapter tool 114 and the connection hole of the square upper support plate 1131, so as to movably connect the adapter tool 114 to the upper surface of the upper support frame 113. Yet further optionally, the upper end surface of the adapter tool 114 has a downward concave groove, and the groove penetrates through the opposite two side surfaces, so as to facilitate the connection of the adapter tool 114 with the measured piece 200 by means of the end shaft neck temporarily installed on the surface of the measured piece 200 and the auxiliary butt joint temporarily installed on the surface of the measured piece 200. Still optionally, the groove is in the shape of a semi-cylinder, and the axis of the groove extends along the horizontal direction.

[0027] When the center of mass is measured by using the mobile center of mass measuring device of the present application, four measuring tools 100 are assembled, arranged in the measuring site, and distributed at the four vertices of a rectangle, and then the end shaft neck / auxiliary docking piece of the measured piece 200 is placed on the upper end of the adapter tool 114, the length of the upper support frame 113 of the measuring tool 100 is adjusted, so that the adapter tool 114 and the four connecting points (i.e., the points where the measured piece 200 is connected with the end shaft neck / auxiliary docking piece) of the measured piece 200 are in the same horizontal plane, the data of the four connecting point distances and the 16 pressure sensors 112 are recorded for the first time, then the measured piece 200 is rotated by 90° around the longitudinal axis, the data of the four connecting point distances and the 16 pressure sensors 112 are recorded for the second time, and the coordinates of the center of mass of the measured piece 200 are obtained through the data recorded twice, which is the existing way of measuring the center of mass. Specifically, the expressions of the X coordinate value, the Y coordinate value and the Z coordinate value of the center of mass of the measured piece 200 are as follows.

[0028] As shown in Figure 3 , assuming that the distances between the four connecting points are L12, L23, L34 and L41 respectively, and the data of the 16 pressure sensors 112 are F11, F12, F13, F14, F21, F22, F23, F24, F31, F32, F33, F34, F41, F42, F43 and F44 respectively, the forces between the four upper support frames 113 and the corresponding lower support frames 111 are F1=F11+F12+F13+F14, F2=F21+F22+F23+F24, F3=F31+F32+F33+F34 and F4=F41+F42+F43+F44 respectively, and then the gravity of the upper support frame G11, G21, G31 and G41 and the gravity of the adapter tool G12, G22, G32 and G42 are subtracted, the forces G1=F1-G11-G12, G2=F2-G21-G22, G3=F3-G31-G32 and G4=F4-G41-G42 applied by the measured piece 200 to the adapter tool 114 can be obtained.

[0029] Further, the mass m=(G1+G2+G3+G4) / g of the measured piece 200 can be obtained, and taking the midpoint of L41 as the origin and the straight line parallel to L12 as the x axis (positive from the No. 1 connecting point to the No. 2 connecting point), and taking L41 as the y axis (positive from the No. 1 connecting point to the No. 4 connecting point), the coordinate value of the center of mass of the measured piece 200 in the xoy plane can be obtained as follows.

[0030] Xcg=(G3×L34+G2×L12) / (G1+G2+G3+G4)

[0031]

[0032] The measured piece 200 is rotated 90° around the x axis, and the hanger / abutment rod at the corresponding position of the measured piece 200 is placed on the upper end of the adapter tool 114, and then the distance between the four connection points is measured again, and the distances L12', L23', L34', and L41', and G1', G2', G3', and G4 are obtained. Taking the midpoint of L41 as the origin, a straight line parallel to L12' as the x axis (pointing from No. 1 connection point to No. 2 connection point as positive), and L41' as the y axis (pointing from No. 1 connection point to No. 4 connection point as positive), the coordinate value of the centroid of the measured piece 200 in the xoy plane is:

[0033] Xcg'=(G3'×L34'+G2'×L12') / (G1'+G2'+G3'+G4')

[0034]

[0035] Obviously, G1+G2+G3+G4=G1'+G2'+G3'+G4', and Xcg=Xcg'.

[0036] The coordinate value of the centroid of the measured piece 200 can be expressed in the following coordinate system:

[0037] Taking the midpoint of L41 as the origin, a straight line parallel to L12 as the x axis (pointing from No. 1 connection point to No. 2 connection point as positive), L41 as the y axis (pointing from No. 1 connection point to No. 4 connection point as positive), and vertically upward as the z axis, the coordinates of the centroid of the measured piece 200 are:

[0038] Xcg=(G3×L34+G2×L12) / (G1+G2+G3+G4)

[0039]

[0040] The mobile centroid measuring device of the application has four independent measuring tools, and there is no connection between the measuring tools. The measuring tools do not need to be fixed on the ground or other platforms, so that the footprint of the centroid measuring device is smaller, and the transportation is also convenient, which reduces the cost of rocket centroid measurement. In addition, the pressure sensor can be selected according to the weight of the measured piece, and the measuring tool can be changed according to the size of the measured piece, so that it can also be applied to the centroid measurement of different measured pieces, so that the range of centroid measurement is wider, and the cost of rocket centroid measurement is also reduced. In addition, different lower support frames and upper support frames can be selected according to the site environment, and the number of measuring tools can be selected according to the actual needs.

[0041] It will be apparent to those skilled in the art that the application is not limited to the details of the foregoing embodiment, and that the application can be implemented in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference herein to an apparatus, article, means, structure, etc. that is discrete per se is intended to exclude the incorporation of such features into other items, components, structures, etc.

[0042] Furthermore, it should be understood that although the description herein is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description herein is made in this way only for the sake of clarity, and those skilled in the art should consider the description as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. A mobile center of mass measuring device, comprising: The application relates to a four-point contact measuring device. The four-point contact measuring device comprises four independent movable measuring tools, and the four measuring tools are distributed to a measuring site and located at four vertices of a rectangle. Each measuring tool comprises a lower support frame, four pressure sensors, an upper support frame and an adapter tool. The upper surface and the lower surface of the lower support frame are horizontal, and the four pressure sensors are arranged on the upper surface of the lower support frame; the upper surface and the lower surface of the upper support frame are horizontal, and the lower surface of the upper support frame is in contact with the upper ends of the four pressure sensors; the lower end of the adapter tool is movably connected to the upper surface of the upper support frame, and the upper end of the adapter tool is used for being connected with a measured piece.

2. The mobile center of mass measurement device of claim 1, wherein, The lower support frame is in the shape of a cuboid, and the long direction of the lower support frame is vertical; the upper support frame is in the shape of a quadrangular frustum, and the high direction of the upper support frame is vertical.

3. The mobile center of mass measurement device of claim 2, wherein, The lower support frame is in the shape of a cuboid, and the long direction of the lower support frame is vertical; the upper support frame is in the shape of a quadrangular frustum, and the high direction of the upper support frame is vertical.

4. The mobile center of mass measurement device of claim 3, wherein, The lower support frame is in the shape of a cuboid, and the long direction of the lower support frame is vertical; the upper support frame is in the shape of a quadrangular frustum, and the high direction of the upper support frame is vertical. The lower support frame comprises a square upper support plate, a square lower support plate and four support columns.

5. The mobile center of mass measurement device of any one of claims 1 to 4, wherein, The upper ends of the four support columns are fixed to the lower surface of the square upper support plate and located near the four vertices of the square upper support plate respectively; the lower ends of the four support columns are fixed to the upper surface of the square lower support plate and located near the four vertices of the square lower support plate respectively; and the four support columns vertically extend to form the cuboid truss structure.

6. The mobile center of mass measurement device of claim 3, wherein, Four limiting frames are fixedly connected to the upper surface of the lower support frame; each pressure sensor is located in a limiting frame, and the inner surface of the limiting frame is in contact with the outer surface of the pressure sensor; and the height of the limiting frame is lower than the height of the pressure sensor. The upper support frame comprises a square upper support plate, a square lower support plate and four support columns.

7. The mobile center of mass measurement device of claim 6, wherein, The upper ends of the four support columns are fixed to the lower surface of the square upper support plate and located near the four vertices of the square upper support plate respectively; the lower ends of the four support columns are fixed to the upper surface of the square lower support plate and located near the four vertices of the square lower support plate respectively; and the four support columns gradually tilt outward from top to bottom to form the quadrangular frustum truss structure.

8. The mobile center of mass measurement device of claim 6, wherein, The top end of each support column of the upper support frame is fixedly connected with the bottom end of a hydraulic cylinder, the top end of each hydraulic cylinder is fixedly connected with the lower surface of the square upper support plate of the upper support frame, and each hydraulic cylinder vertically extends.

9. The mobile center of mass measurement device of claim 6, wherein, The lower end of the adapter tool has a connecting hole penetrating through the upper and lower ends, the square upper support plate of the upper support frame has a connecting hole penetrating through the upper and lower ends at the middle position, and a bolt passes through the connecting hole of the adapter tool and the connecting hole of the square upper support plate of the upper support frame to movably connect the adapter tool to the upper surface of the upper support frame. The upper end surface of the adapter tool has a downwardly recessed groove, and the groove penetrates through the opposite two side surfaces.

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