An aircraft center of gravity measurement device and method of use

Abstract

The application discloses an aircraft center of gravity measuring device, which comprises a carrying platform, a stop block, four semispherical support points, eight pressure sensors, eight rollers, a foundation I, a foundation II, a stand, a ball, a foundation stand and a measuring circuit; the stop block is connected to the carrying platform; one end of the four semispherical support points is welded to the four corners of the bottom of the carrying platform, and the other end is pressed on the four pressure sensors; the four pressure sensors are respectively arranged on the rollers; the rollers are respectively arranged on one end of the foundation I and the foundation II; the stand is connected to the front and back sides of the left end of the carrying platform; a spherical groove is arranged on the upper and lower ends of the stand; a ball is arranged in the spherical groove; the foundation stand is arranged on the other end of the foundation I; one end of the other four pressure sensors is arranged on the upper and lower ends of the foundation stand; the other end of the other four pressure sensors is pressed on the ball; and the eight pressure sensors are electrically connected to the measuring circuit.

Description

Technical Field

[0001] This invention belongs to the field of aircraft center of gravity measurement technology, specifically, it relates to an aircraft center of gravity measurement device and its usage method. Background Technology

[0002] The center of gravity of an aircraft is a crucial data point in aircraft design and operation, affecting its stability, handling characteristics, and load distribution. Therefore, measuring the aircraft's center of gravity is a vital task. Aircraft are large pieces of equipment, and measuring their center of gravity is a difficult and complex undertaking. Existing methods for measuring aircraft center of gravity are overly complicated. For example, existing literature, such as "Research on Aircraft Weight and Center of Gravity Measurement and Calculation Methods" (author: Liu Desheng, 2008 Academic Exchange of the Chinese Society of Aeronautics and Astronautics), requires using jacks to lift the aircraft to a horizontal position and then performing secondary attitude adjustments. These are highly precision-required tasks, requiring coordination among multiple people, resulting in a significant workload. Furthermore, the secondary positioning after attitude adjustment introduces positioning errors.

[0003] Therefore, an aircraft center of gravity measuring device and its usage method are provided, which can obtain more accurate aircraft center of gravity data through simple operation. Summary of the Invention

[0004] In view of the above-mentioned prior art, the purpose of this invention is to overcome the shortcomings of the prior art, adapt to the needs of reality, and thus provide an aircraft center of gravity measuring device and its usage method that can solve the problems of existing aircraft center of gravity measurement methods being too complex and having errors, and can obtain more accurate aircraft center of gravity data through simple operation.

[0005] To achieve the above objectives, the technical solution adopted by this invention is as follows: an aircraft center of gravity measuring device, comprising a cargo platform, a stop block, a reinforcing beam, hemispherical support points, pressure sensors, rollers I, foundation I, foundation II, columns, ball bearings, foundation columns, and a measuring circuit; the stop block is bolted to the top of the cargo platform, the reinforcing beam is welded to the bottom of the cargo platform, four hemispherical support points and four rollers I are provided, eight pressure sensors are provided, two columns, two foundation columns, two foundations I, and two foundations II are provided, one end of each of the four hemispherical support points is welded to the four corners of the bottom of the cargo platform, and the other end is pressed onto one of the four pressure sensors, wherein the four pressure sensors are respectively placed on the four rollers I, and the four rollers I are respectively placed on one end of the two foundations I and the two foundations II, the two foundations I being located on the left side of the cargo platform, and the two foundations II being located on the right side of the cargo platform; two columns... One end of each column is connected to the front and rear sides of the left end of the loading platform. Each of the two columns has a spherical groove for installing ball bearings at both the upper and lower ends of the left side, and each spherical groove contains one ball bearing. One end of each of the two foundation columns is installed on the other end of the two foundations I, and both foundation columns are located on the left side of the two columns. One end of each of the four pressure sensors is installed on the upper and lower ends of the right side of the two foundation columns by bolts, and the other end is pressed on the ball bearings. All eight pressure sensors are connected to the measuring circuit by wires. The four pressure sensors installed at the bottom of the loading platform are labeled P00, PXX, PXZ and PZZ in a counterclockwise direction, starting from the pressure sensor at the left front end. The four pressure sensors installed on the foundation columns are labeled L00, LZZ, LYZ and LYY in a clockwise direction, starting from the pressure sensor at the lower end of the front foundation column.

[0006] Furthermore, both foundation columns are bolted to the other end of the two foundations I.

[0007] Furthermore, the pressure sensor includes an upper housing, an upper transmission block, a measuring plate, a resistance strain gauge, a lower transmission block, a lower housing, and a spring; the upper housing has a through hole in the middle that connects to the column of the upper transmission block, the upper housing presses on the upper end of the spring, one end of the upper transmission block is connected to the upper housing, and the other end is welded to one end of the measuring plate, the other end of the measuring plate is welded to one end of the lower transmission block, the resistance strain gauge is glued to the middle of the measuring plate and connected to the measuring circuit through wires, the other end of the lower transmission block is connected to the lower housing by bolts, and the lower housing is supported on the lower end of the spring.

[0008] Furthermore, the measurement circuit includes a power supply, a switch, P00 strain gauges, PXX strain gauges, PXZ strain gauges, PZZ strain gauges, an X-coordinate voltmeter, a Z-coordinate voltmeter, an L00 strain gauge, an LZZ strain gauge, an LYZ strain gauge, an LYY strain gauge, and a Y-coordinate voltmeter; the P00, PXX, PXZ, and PZZ strain gauges are connected in series, and the L00, LZZ, LYZ, and LYY strain gauges are connected in series. The series-connected P00, PXX, PXZ, and PZZ strain gauges are connected in parallel with the series-connected L00, LZZ, LYZ, and LYY strain gauges, and this parallel connection is then connected in series with the power supply and the switch; the X-coordinate voltmeter is connected in parallel with the PXX and PXZ strain gauges. The coordinate voltmeter is used to measure the voltage values ​​of PXX and PXZ strain gauges. The Z-coordinate voltmeter is connected in parallel with the PXZ and PZZ strain gauges. The Y-coordinate voltmeter is connected in parallel with the LYZ and LYY strain gauges. The P00, PXX, PXZ, and PZZ strain gauges correspond to the resistive strain gauges in the pressure sensors labeled P00, PXX, PXZ, and PZZ, respectively. The L00, LZZ, LYZ, and LYY strain gauges correspond to the resistive strain gauges in the pressure sensors labeled L00, LZZ, LYZ, and LYY, respectively.

[0009] Furthermore, the blocks include a front wheel block, a right rear wheel block, and a left rear wheel block. The front wheel block, right rear wheel block, and left rear wheel block contact the front wheel, right rear wheel, and left rear wheel of the aircraft, respectively, and are used to restrict the position of the front wheel, right rear wheel, and left rear wheel, respectively. The position of the front wheel block can be adjusted according to the front and rear wheel track of the aircraft. The front wheel block, right rear wheel block, and left rear wheel block have the same structural shape.

[0010] Furthermore, the loading platform is a square flat plate. A hemispherical support point is welded to each of the four corners of the platform's bottom. The projection points of the centers of these four hemispherical support points onto the top of the loading platform are sequentially connected and marked with scales. The lines connecting the four projection points are parallel to the four edges of the loading platform, front, back, left, and right. The projection point on the left front end of the loading platform is the origin of the coordinate system. The line parallel to the front side of the loading platform is the X-axis scale line, and the line parallel to the left side of the loading platform is the Z-axis scale line. The distance between adjacent hemispherical support points is L. A column is welded to each of the two corners of the front and rear ends of the left side of the loading platform, and the loading platform is perpendicular to the columns. A long, narrow bolt hole is opened at the center of the front side of the top of the loading platform, facing rearward, for connecting the front wheel stops. This long, narrow bolt hole is used to install and adjust the position of the front wheel stops.

[0011] Furthermore, roller I is a bearing structure composed of multiple cylinders, including roller II, frame and shaft. There are multiple roller II, all of which are cylindrical structures. Multiple roller II are set in the frame through the shaft. Roller I can roll to reduce the friction between the loading platform and foundation I and foundation II.

[0012] Furthermore, the upper surfaces of both foundation I and foundation II are parallel to the loading platform and form a certain angle with the horizontal plane (which can be set according to the actual situation). The lower surfaces are both flat. Both foundation I and foundation II are provided with bosses to restrict the slippage of roller I, and one end of each of the two foundation columns is fixed to the boss of foundation I by bolts.

[0013] Furthermore, foundation I and foundation II have the same structure, and the total height of foundation II is greater than the total height of foundation I.

[0014] Furthermore, one end of each of the two columns is welded to the front and rear corners of the left side of the loading platform, and both are perpendicular to the loading platform. The center of the spherical groove located at the lower left end of the column is on the same surface as the upper surface of the loading platform. The distance between the spherical groove at the upper left end and the spherical groove at the lower left end of the same column is L. The distance between the spherical grooves at the upper left end of different columns and the distance between the spherical grooves at the lower left end of different columns are both L.

[0015] Furthermore, the ball bearings are spherical and installed in the spherical groove of the column. The ball bearings can roll relative to the spherical groove of the column to reduce the friction between the column and the foundation column.

[0016] Furthermore, the foundation columns are parallel to each other and are all perpendicular to the upper surface of foundation I.

[0017] Furthermore, both the uploading and downloading blocks are "[" shaped cubes, which, when combined, can convert the pressure transmitted by the upper shell into a tensile force acting on the measuring plate.

[0018] Furthermore, the measuring plate is a thin steel plate with a high elastic modulus, and the resistance value of the resistance strain gauge is proportional to the load on the measuring plate.

[0019] Furthermore, the range of the pressure sensor is directly proportional to the stiffness of the spring.

[0020] Furthermore, both the upper and lower shells are cylindrical structures, and the outer diameter of the upper shell matches the inner diameter of the lower shell. Both the upper and lower shells are supported by springs, upper load blocks, and lower load blocks.

[0021] A method of using the aircraft center of gravity measuring device as described above, the method comprising: Tow the aircraft onto the cargo platform to the stop. When towing the aircraft onto the cargo platform, the left and right rear wheels of the aircraft need to be in full contact with the left and right rear wheel guards. This will make the aircraft's coordinate system parallel to the cargo platform's coordinate system. Adjust the position of the front wheel guard to contact the aircraft's front wheels to fix the aircraft. The coordinates of the aircraft wheels on the cargo platform can be measured by using graduated lines on the platform. ,0, ); Read the voltmeter readings from the measurement circuit. The circuit reads the X-coordinate voltmeter voltage value (UX), the Z-coordinate voltmeter voltage value (UZ), and the Y-coordinate voltmeter voltage value (UY) respectively. Calculate the aircraft's center of gravity coordinates as follows: , , Since the distance between support points L and the power supply voltage U are fixed values, therefore Since it is a constant, simply changing the dial of the voltmeter allows direct reading of the aircraft's center of gravity coordinates via the measuring circuit. The resulting center of gravity coordinates are relative to the platform's coordinate system, while the coordinates relative to the aircraft's wheels are: , and This means obtaining the coordinates of the aircraft's center of gravity relative to the wheels.

[0022] The beneficial effects of this invention are as follows: When using this device to measure the center of gravity of an aircraft, it is only necessary to tow the aircraft onto a loading platform, measure the coordinates of the wheels on the platform, and then input the data measured by each pressure sensor into the formula to obtain the center of gravity of the aircraft. Compared with existing methods for measuring the center of gravity of aircraft, this invention is simpler to operate, requiring no adjustment of the aircraft to a horizontal attitude or secondary adjustment of the aircraft position. This reduces the workload during the measurement process and avoids errors caused by adjusting the aircraft attitude and secondary positioning. The pressure sensor used in this invention converts pressure into tension on the measuring plate through upper and lower transmission blocks. The measuring plate will not become unstable under tension, so the measuring plate can be made very thin, improving the sensitivity of the pressure sensor. By replacing the spring of the pressure sensor, the range of the sensor can be changed without replacing other parts, making it convenient to use and low in cost. The measuring circuit used in this invention measures UX, UY, and UZ, which are proportional to the center of gravity coordinates X, Y, and Z, through a simple circuit relationship, thereby obtaining the center of gravity data of the aircraft. This invention is simple to operate, has small errors, a clear principle, is easy to produce, has strong practicality, is easy to promote and apply, and has great value. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the assembly structure of the present invention; Figure 2This is a schematic diagram of the structure of the cargo platform of the present invention; Figure 3 This is a schematic diagram of the structure of the stop block of the present invention; Figure 4 This is a schematic diagram of the structure of the reinforcing beam of the present invention; Figure 5 This is a schematic diagram of the hemispherical support point of the present invention; Figure 6 This is a schematic diagram of the structure of roller I of the present invention; Figure 7 This is a schematic diagram of the structure of foundation I of the present invention; Figure 8 This is a schematic diagram of the structure of foundation II of the present invention; Figure 9 This is a schematic diagram of the structure of the column of the present invention; Figure 10 This is a schematic diagram of the structure of the ball bearing of the present invention; Figure 11 This is a schematic diagram of the foundation column of the present invention; Figure 12 This is a schematic diagram of the pressure sensor structure of the present invention; Figure 13 This is a schematic diagram of the connection of the measurement circuit of the present invention.

[0024] Among them, 1-carrying platform, 2-stop block, 3-reinforcing beam, 4-hemispherical support point, 5-platform pressure sensor, 6-roller I, 7-foundation I, 8-column, 9-ball bearing, 10-foundation column, 11-measuring circuit, 12-long strip bolt hole, 13-projection point of the center of the hemispherical support point on the carrying platform (i.e., coordinate origin), 14-X-axis scale line, 15-Z-axis scale line, 16-front wheel stop block, 17-right rear wheel stop block, 18-left rear wheel stop block, 19-P00 support point, 20-PXX support point, 21-PXZ support point, 22-PZZ support point, 23-roller II, 24-frame, 25-rotating shaft, 27- L00 ball bearing, 28-LZZ ball bearing, 29-LYZ ball bearing, 30-LYY ball bearing, 26-spherical groove, 31-upper housing, 32-upper load block, 33-measuring plate, 34-resistive strain gauge, 35-lower load block, 36-lower housing, 37-spring, 38-power supply, 39-switch, 40-P00 strain gauge, 41-PXX strain gauge, 42-PXZ strain gauge, 43-PZZ strain gauge, 44-X coordinate voltmeter, 45-Z coordinate voltmeter, 46-L00 strain gauge, 47-LZZ strain gauge, 48-LYZ strain gauge, 49-LYY strain gauge, 50-Y coordinate voltmeter, 51-foundation II. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0026] like Figures 1 to 13 As shown, the present invention provides an aircraft center of gravity measuring device, including a cargo platform 1, a stop block 2, a reinforcing beam 3, a hemispherical support point 4, a pressure sensor 5, rollers I 6, a foundation I 7, a foundation II 51, a column 8, ball bearings 9, a foundation column 10, and a measuring circuit 11; the stop block 2 is bolted to the top of the cargo platform 1, the reinforcing beam 3 is welded to the bottom of the cargo platform 1, there are four hemispherical support points 4 and four rollers I 6, eight pressure sensors 5, and the column 8 and foundation column... 10. Both foundation I7 and foundation II51 have two sets of four hemispherical support points 4, one end of which is welded to the four corners of the bottom of the loading platform 1, and the other end of which is pressed onto one of the four pressure sensors 5. The four pressure sensors 5 are placed on four rollers I6, and the four rollers I6 are placed on one end of the two foundations I7 and the two foundations II51. The two foundations I7 are located on the left side of the loading platform 1, and the two foundations II51 are located on the right side of the loading platform 1; two columns One end of each column 8 is connected to the front and rear sides of the left end of the loading platform 1. Each of the two columns 8 has a spherical groove 26 for installing a ball bearing 9 at both the upper and lower ends of the left side, and each spherical groove 26 has a ball bearing 9 installed in it. One end of each of the two foundation columns 10 is installed on the other end of the two foundations I 7, and both foundation columns 10 are located on the left side of the two columns 8. One end of each of the four pressure sensors 5 is installed on the upper and lower ends of the right side of the two foundation columns 10 by bolts, and the other end is pressed on the ball bearing 9. All eight pressure sensors 5 are connected to the measuring circuit 11 by wires. The four pressure sensors 5 installed at the bottom of the loading platform 1 are labeled P00, PXX, PXZ and PZZ in a clockwise direction starting from the pressure sensor 5 at the left front end. The four pressure sensors 5 installed on the foundation columns 10 are labeled L00, LZZ, LYZ and LYY in a clockwise direction starting from the pressure sensor 5 at the lower end of the front foundation column 10.

[0027] Preferably, both foundation columns 10 are bolted to the other end of the two foundations I7.

[0028] Preferably, the pressure sensor 5 includes an upper housing 31, an upper transmission block 32, a measuring plate 33, a resistance strain gauge 34, a lower transmission block 35, a lower housing 36, and a spring 37. The upper housing 31 has a through hole in the middle that connects to the column of the upper transmission block 32. The upper housing 31 presses against the upper end of the spring 37. One end of the upper transmission block 32 is connected to the upper housing 31, and the other end is welded to one end of the measuring plate 33. The other end of the measuring plate 33 is welded to one end of the lower transmission block 35. The resistance strain gauge 34 is glued to the middle of the measuring plate 33 and connected to the measuring circuit 11 through a wire. The other end of the lower transmission block 35 is bolted to the lower housing 36, and the lower housing 36 is supported on the lower end of the spring 37.

[0029] Preferably, the measuring circuit 11 includes a power supply 38, a switch 39, a P00 strain gauge 40, a PXX strain gauge 41, a PXZ strain gauge 42, a PZZ strain gauge 43, an X-coordinate voltmeter 44, a Z-coordinate voltmeter 45, an L00 strain gauge 46, an LZZ strain gauge 47, an LYZ strain gauge 48, an LYY strain gauge 49, and a Y-coordinate voltmeter 50; the P00 strain gauge 40, PXX strain gauge 41, PXZ strain gauge 42, and PZZ strain gauge 43 are connected in series. L00 strain gauge 46, LZZ strain gauge 47, LYZ strain gauge 48, and LYY strain gauge 49 are connected in series. The series-connected P00 strain gauge 40, PXX strain gauge 41, PXZ strain gauge 42, and PZZ strain gauge 43 are then connected in parallel with the series-connected L00 strain gauge 46, LZZ strain gauge 47, LYZ strain gauge 48, and LYY strain gauge 49. This parallel connection is then connected in series with power supply 38 and switch 39. X-coordinate voltmeter 44 is connected in series with PXX strain gauge 41 and PXZ strain gauge 42. Z-strain gauge 42 is connected in parallel. X-coordinate voltmeter 44 is used to measure the voltage values ​​of PXX strain gauge 41 and PXZ strain gauge 42. Z-coordinate voltmeter 45 is connected in parallel with PXZ strain gauge 42 and PZZ strain gauge 43. Z-coordinate voltmeter 45 is used to measure the voltage values ​​of PXZ strain gauge 42 and PZZ strain gauge 43. Y-coordinate voltmeter 50 is connected in parallel with LYZ strain gauge 48 and LYY strain gauge 49. Y-coordinate voltmeter 50 is used to measure the voltage values ​​of LYZ strain gauge 48 and LYY strain gauge 49. The voltage value of Y strain gauge 49, P00 strain gauge 40, PXX strain gauge 41, PXZ strain gauge 42 and PZZ strain gauge 43 correspond to the resistive strain gauge 34 in the pressure sensor labeled P00, PXX, PXZ and PZZ respectively, and L00 strain gauge 46, LZZ strain gauge 47, LYZ strain gauge 48 and LYY strain gauge 49 correspond to the resistive strain gauge 34 in the pressure sensor labeled L00, LZZ, LYZ and LYY respectively.

[0030] Preferably, the stop block 2 includes a front wheel stop block 16, a right rear wheel stop block 17, and a left rear wheel stop block 18. The front wheel stop block 16, the right rear wheel stop block 17, and the left rear wheel stop block 18 contact the front wheel, the right rear wheel, and the left rear wheel of the aircraft, respectively, and are used to restrict the position of the front wheel, the right rear wheel, and the left rear wheel of the aircraft, respectively. The position of the front wheel stop block 16 can be adjusted according to the front and rear wheel track of the aircraft. The front wheel stop block 16, the right rear wheel stop block 17, and the left rear wheel stop block 18 have the same structural shape.

[0031] Preferably, the loading platform 1 is a square flat plate. A hemispherical support point 4 is welded to each of the four corners of the bottom of the loading platform 1. The projection points of the centers of the hemispherical support points 4 onto the upper end of the loading platform 1 are connected in sequence and marked with scales. The lines connecting the four projection points are parallel to the four edges of the loading platform 1. The projection point located on the left front end of the loading platform 1 is the origin of the coordinate system 13. The line parallel to the front side of the loading platform 1 is the X-axis scale line 14, and the line parallel to the left side of the loading platform 1 is the Z-axis scale line 15. The distance between adjacent hemispherical support points 4 is L. A column 8 is welded to each of the two corners of the front and rear ends of the left side of the loading platform 1. The loading platform 1 is perpendicular to the column 8. A long strip bolt hole 12 for connecting the front wheel stop 16 is opened in the middle of the front side of the upper end of the loading platform 1, facing the rear side. The long strip bolt hole is used to install and adjust the position of the front wheel stop 16.

[0032] Preferably, roller I6 is a bearing structure composed of multiple cylinders, including roller II23, frame 24 and shaft 25. Multiple roller II23 are provided, all of which are cylindrical structures. Multiple roller II23 are disposed in the frame 24 through shaft 25. Roller I6 can roll to reduce the friction between the loading platform 1 and the foundation I7 and foundation II51.

[0033] Preferably, the upper surfaces of foundation I7 and foundation II51 are parallel to the loading platform 1 and form a certain angle with the horizontal plane (which can be set according to the actual situation), and the lower surfaces are both flat. Both foundation I7 and foundation II51 are provided with bosses to limit the slippage of roller I6, and one end of each of the two foundation columns 10 is fixed to the boss of foundation I7 by bolts.

[0034] Preferably, foundation I7 and foundation II51 have the same structure, and the total height of foundation II51 is greater than the total height of foundation I7.

[0035] Preferably, one end of each of the two columns 8 is welded to the front and rear corners of the left side of the loading platform 1, and both are perpendicular to the loading platform 1. The center of the spherical groove 26 located at the lower left end of the column 8 is on the same plane as the upper surface of the loading platform 1. The distance between the spherical groove 26 located at the upper left end and the spherical groove 26 located at the lower left end of the same column 8 is L. The distance between the spherical grooves 26 located at the upper left end of different columns 8 and the distance between the spherical grooves 26 located at the lower left end of different columns 8 are both L.

[0036] Preferably, the ball bearing 9 is spherical and is installed in the spherical groove 26 of the column 8. The ball bearing 9 can roll relative to the spherical groove 26 of the column 8 to reduce the friction between the column 8 and the foundation column 10.

[0037] Preferably, the foundation column 10 is parallel to the column 8 and both are perpendicular to the upper surface of the foundation I7.

[0038] Preferably, both the uploading block 32 and the downloading block 35 are "[" shaped blocks, which, when combined, can convert the pressure transmitted by the upper housing 31 into a tensile force acting on the measuring plate 33.

[0039] Preferably, the measuring plate 33 is a thin steel plate with a large elastic modulus, and the resistance value of the resistive strain gauge 34 is proportional to the load on the measuring plate 33.

[0040] Preferably, the range of the pressure sensor 5 is proportional to the stiffness of the spring 37.

[0041] Preferably, both the upper housing 31 and the lower housing 36 are cylindrical structures, and the outer diameter of the upper housing 31 matches the inner diameter of the lower housing 36. Both the upper housing 31 and the lower housing 36 are supported by the spring 37, the upper load block 32, and the lower load block 35.

[0042] A method of using the aircraft center of gravity measuring device as described above, the method comprising: Tow the aircraft onto the cargo platform 1 to the stop 2. When towing the aircraft onto the cargo platform 1, the left and right rear wheels of the aircraft need to be in full contact with the left rear wheel baffle 18 and the right rear wheel baffle 17. This will make the aircraft's coordinate system parallel to the coordinate system of the cargo platform 1. Adjust the position of the front wheel baffle 16 to contact the front wheels of the aircraft to fix the aircraft. The coordinates of the aircraft wheels on platform 1 are measured by using the graduated lines on platform 1. ,0, ); Read the voltmeter readings in measurement circuit 11. Using measurement circuit 11, read the voltage values ​​from X-coordinate voltmeter 44 (UX), Z-coordinate voltmeter 45 (UZ), and Y-coordinate voltmeter 50 (UY) respectively. Calculate the aircraft's center of gravity coordinates as follows: , , Since the distance between support points L and the power supply voltage U are fixed values, therefore Since it is a constant, simply changing the dial of the voltmeter allows direct reading of the aircraft's center of gravity coordinates via measuring circuit 11. The read center of gravity coordinates are relative to the coordinate system of the cargo platform 1, while the coordinates relative to the aircraft wheels are: , and This means obtaining the coordinates of the aircraft's center of gravity relative to the wheels.

[0043] In this invention, the main structure of the device consists of a cargo platform 1 and a column 8 that are perpendicular to each other. The cargo platform 1 has a certain tilt angle with the horizontal plane, which can decompose the gravity of the aircraft into two components perpendicular to the cargo platform 1 and perpendicular to the column 8. The cargo platform 1 is equipped with four pressure sensors 5. By using the principle of force balance, the coordinates of the point of application of the component force on the cargo platform 1 can be calculated. The column 8 is equipped with four ball bearings 9, which press against the four pressure sensors 5. By using the principle of force balance, the coordinates of the point of application of the component force on the column 8 can be calculated.

[0044] In this invention, a stop block 2 is installed on the upper surface of the cargo platform 1. The stop block 2 is made of rubber and is connected to the cargo platform 1 by bolts. The pressure generated by tightening the bolts can increase the friction between the stop block 2 and the cargo platform 1, thereby restricting the movement of the aircraft wheels. A reinforcing beam 3 is welded to the lower surface of the cargo platform 1 to improve the rigidity of the platform. Hemispherical support points 4 are welded to the four corners of the bottom of the cargo platform 1. A pressure sensor 5 is installed under each hemispherical support point 4. A roller I 6 is installed under each pressure sensor 5. Each roller I 6 is installed on a foundation. The roller I 6 consists of a set of cylindrical rollers II 23, a frame 24 and a rotating shaft 25. It can roll to reduce the friction between the pressure sensor 5 and the foundation I 7 and foundation II 51. The upper surfaces of both foundation I7 and foundation II51 are parallel to the cargo platform 1 and form a certain angle with the horizontal plane, so that the cargo platform 1 installed on the foundation forms a certain angle with the horizontal plane. This can decompose the aircraft's gravity into two components: one perpendicular to the cargo platform 1 and the other perpendicular to the column 8.

[0045] In this invention, the column 8 is welded to the loading platform 1. Both the upper and lower ends of the column 8 are provided with spherical grooves 26. The ball bearing 9 is installed in the spherical grooves 26 of the column and can roll to reduce the friction between the column 8 and the foundation column 10. The ball bearing 9 presses on the pressure sensor 5, which is fixed to the foundation column 10. The foundation column 10 is parallel to the column 8 and is perpendicular to the upper surface of the foundation I7. The foundation column 10 is fixed to the foundation I7 by bolts.

[0046] In this invention, all eight pressure sensors 5 convert the pressure on the upper housing 31 into a tensile force on the measuring plate 33 through the upper load block 32 and the lower load block 35. Since the measuring plate 33 will not become unstable under tension, it can be very thin and can produce large deformation even under small loads, thereby improving the sensitivity of the pressure sensors 5. The resistive strain gauge 34 is glued to the measuring plate 33 and connected to the measuring circuit 11 through wires. The resistance value of the resistive strain gauge 34 is proportional to the load on the measuring plate 33. Each pressure sensor 5 is equipped with a spring 37, which can share part of the pressure load. If a spring 37 with high stiffness is selected, the range of the pressure sensor 5 will be larger; if a spring 37 with low stiffness is selected, the range of the pressure sensor 5 will be smaller. In this way, by replacing the spring of the pressure sensor 5, the range of the sensor can be changed without replacing other parts, which is convenient to use and low in cost.

[0047] In this invention, four pressure sensors 5 are installed at the four corners of the loading platform 1. The pressure sensors 5 at the four corners are labeled P00, PXX, PXZ, and PZZ in a clockwise direction starting from the left front point. The other four pressure sensors 5 are installed at the upper and lower ends of the two foundation columns 10. The four pressure sensors 5 installed on the foundation columns 10 are labeled L00, LZZ, LYZ, and LYY in a clockwise direction starting from the lower end of the front foundation column 10. The resistive strain gauges 34 in the eight pressure sensors 5 are all connected to the measuring circuit 11 through wires.

[0048] In this invention, the measuring circuit 11 consists of a series-connected P00 strain gauge 40, PXX strain gauge 41, PXZ strain gauge 42, and PZZ strain gauge 43 connected in parallel with a series-connected L00 strain gauge 46, LZZ strain gauge 47, LYZ strain gauge 48, and LYY strain gauge 49, which are then connected in series with a power supply 38 and a switch 39. An X-coordinate voltmeter 44 is connected in parallel with the PXX strain gauge 41 and PXZ strain gauge 42, and is used to measure the voltage values ​​of the PXX strain gauge 41 and PXZ strain gauge 42. A Z-coordinate voltmeter 45 is connected in parallel with the PXZ strain gauge 42 and PZZ strain gauge 43, and is used to measure the voltage values ​​of the PXZ strain gauge 42 and PZZ strain gauge 43. A Y-coordinate voltmeter 50 is connected in parallel with the LYZ strain gauge 48 and LYY strain gauge 49, and is used to measure the voltage values ​​of the LYZ strain gauge 48 and LYY strain gauge 49.

[0049] In this invention, the platform 1 and the column 8 are perpendicular to each other. The upper surface of the platform 1 is marked as the XY plane, and the right side of the column 8 is marked as the YZ plane. A pressure sensor 5 is installed at each of the four corners of the platform 1. The pressure sensors 5 at the four corners are marked as P00, PXX, PXZ, and PZZ in a counterclockwise direction starting from the left front point. The line connecting P00 and PZZ is the Z-axis. The torque balance is calculated about the Z-axis of the line connecting P00 and PZZ. Derivation The line connecting P00 and PXX is the X-axis. Find the torque balance about the X-axis of the line connecting P00 and PXX: Derivation A pressure sensor 5 is installed at both the upper and lower ends of the two foundation columns 10. The four pressure sensors 5 are labeled L00, LZZ, LYZ, and LYY in a clockwise direction, starting from the pressure sensor 5 at the lower end of the front foundation column 10. The line connecting L00 and LZZ is the Z-axis. Calculate the torque balance about the Z-axis of the line connecting L00 and LZZ: Derivation .

[0050] In this invention, since the load P on the pressure sensor 5 is proportional to the resistance R of the resistive strain gauge 34, therefore: , , Since the resistance of a resistor in a series circuit is directly proportional to the voltage applied to it, therefore: Can be launched , Can be launched , Can be launched Substituting into the coordinate calculation formula, we can obtain: , and Since the support point spacing L and the power supply voltage U are fixed values, therefore Since it is a constant, simply changing the dial of the voltmeter allows direct reading of the aircraft's center of gravity coordinates via the measuring circuit. At this point, the center of gravity coordinates are relative to the coordinate system of platform 1, and the coordinates relative to the aircraft wheels are: , , From this, we can obtain the coordinates of the aircraft's center of gravity relative to the wheels.

[0051] In this invention, the resistive strain gauge 34 in the pressure sensor 5 is the same strain gauge in the measuring circuit 11. The pressure sensor 5 can change the resistance value of the resistive strain gauge 34 according to the load it is subjected to. The load magnitude is proportional to the resistance value of the resistive strain gauge 34.

[0052] In this invention, the hemispherical support points 4 installed at the four corners of the bottom of the loading platform 1 are sequentially labeled P00 support point 19, PXX support point 20, PXZ support point 21, and PZZ support point 22 in a counterclockwise direction, starting from the left front end of the loading platform 1. The positions of P00 support point 19, PXX support point 20, PXZ support point 21, and PZZ support point 22 correspond to the pressure sensors 5 labeled P00, PXX, PXZ, and PZZ, respectively, and can transmit the force on the four support points to... On the corresponding pressure sensor; the four balls 9 mounted on the column 8 are labeled L00 ball 27, LZZ ball 28, LYZ ball 29 and LYY ball 30 in a clockwise direction, starting from the ball 9 at the lower end of the front column 8. The positions of L00 ball 27, LZZ ball 28, LYZ ball 29 and LYY ball 30 correspond to the pressure sensors 5 labeled L00, LZZ, LYZ and LYY, respectively, and can transmit the force on the four balls 9 to the corresponding pressure sensors.

[0053] When measuring an aircraft's center of gravity, this device only requires towing the aircraft onto a platform, measuring the coordinates of the wheels on the platform, and then inputting the data measured by each pressure sensor into a formula to obtain the aircraft's center of gravity. Compared with existing methods for measuring aircraft center of gravity, this invention is simpler to operate, eliminating the need to adjust the aircraft to a horizontal attitude or perform secondary adjustments. This reduces the workload during the measurement process and avoids errors caused by adjusting the aircraft's attitude and secondary positioning. This invention is simple to operate, has low error, a clear principle, is easy to manufacture, highly practical, and easy to promote and apply, thus possessing significant value.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0055] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments. For example, any of the claimed embodiments in the foregoing claims can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of the invention and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. An aircraft center of gravity measuring device, characterized in that: The system includes a loading platform, stops, reinforcing beams, hemispherical support points, pressure sensors, roller I, foundation I, foundation II, columns, ball bearings, foundation columns, and measuring circuitry. The stops are bolted to the top of the loading platform. The reinforcing beams are welded to the bottom of the loading platform. There are four hemispherical support points and four rollers I. There are eight pressure sensors. The columns, foundation columns, foundation I, and foundation II each have two support points. One end of each of the four hemispherical support points is welded to one of the four corners of the bottom of the loading platform, and the other end presses against one of the four pressure sensors. Each of the four pressure sensors is individually mounted on... The load is placed on four rollers I, each roller I resting on one end of two foundations I and two foundations II. Foundations I are located on the left side of the platform, and foundations II are located on the right side. Two uprights are connected at one end to the front and rear sides of the left end of the platform. Each upright has a spherical groove at its upper and lower left sides for mounting ball bearings, with one ball bearing installed in each groove. One end of each of the two foundation uprights is mounted on the other end of the two foundations I, and both uprights are located on the left side of the two foundations. Four pressure sensors are mounted at one end using bolts. At the upper and lower ends of the two foundation columns on the right side, and with the other end pressed against the ball bearings, eight pressure sensors are connected to the measuring circuit via wires. The four pressure sensors installed at the bottom of the platform are labeled P00, PXX, PXZ, and PZZ in a counter-clockwise direction, starting from the pressure sensor at the left front end. The four pressure sensors installed on the foundation columns are labeled L00, LZZ, LYZ, and LYY in a clockwise direction, starting from the pressure sensor at the lower end of the front foundation column. The pressure sensors include an upper housing, an upper loading block, a measuring plate, and a resistive strain gauge. The system comprises a plate, a lower transmission block, a lower housing, and a spring. The upper housing has a through hole in the middle that connects to the column of the upper transmission block. The upper housing presses against the upper end of the spring. One end of the upper transmission block is connected to the upper housing, and the other end is welded to one end of the measuring plate. The other end of the measuring plate is welded to one end of the lower transmission block. The resistance strain gauge is glued to the middle of the measuring plate and connected to the measuring circuit through wires. The other end of the lower transmission block is bolted to the lower housing, and the lower housing is supported at the lower end of the spring. Both the upper and lower transmission blocks are "[" shaped blocks. When combined, they can convert the pressure transmitted by the upper housing into a tensile force acting on the measuring plate.

2. The aircraft center of gravity measuring device according to claim 1, characterized in that: Both foundation columns are bolted to the other end of the two foundations I.

3. The aircraft center of gravity measuring device according to claim 1, characterized in that: The measurement circuit includes a power supply, a switch, P00 strain gauges, PXX strain gauges, PXZ strain gauges, PZZ strain gauges, an X-coordinate voltmeter, a Z-coordinate voltmeter, L00 strain gauges, LZZ strain gauges, LYZ strain gauges, LYY strain gauges, and a Y-coordinate voltmeter. The P00, PXX, PXZ, and PZZ strain gauges are connected in series; the L00, LZZ, LYZ, and LYY strain gauges are connected in series; the series-connected P00, PXX, PXZ, and PZZ strain gauges are connected in parallel with the series-connected L00, LZZ, LYZ, and LYY strain gauges, and this parallel connection is then connected in series with the power supply and the switch. The X-coordinate voltmeter is connected in parallel with the PXX and PXZ strain gauges. A voltmeter is used to measure the voltage values ​​of PXX and PXZ strain gauges. A Z-coordinate voltmeter is connected in parallel with PXZ and PZZ strain gauges to measure their voltage values. A Y-coordinate voltmeter is connected in parallel with LYZ and LYY strain gauges to measure their voltage values. P00, PXX, PXZ, and PZZ strain gauges correspond to the resistive strain gauges in pressure sensors labeled P00, PXX, PXZ, and PZZ, respectively. L00, LZZ, LYZ, and LYY strain gauges correspond to the resistive strain gauges in pressure sensors labeled L00, LZZ, LYZ, and LYY, respectively.

4. The aircraft center of gravity measuring device according to claim 1, characterized in that: The blocks include a front wheel block, a right rear wheel block, and a left rear wheel block. The front wheel block, right rear wheel block, and left rear wheel block contact the front wheel, right rear wheel, and left rear wheel of the aircraft, respectively, and are used to limit the position of the front wheel, right rear wheel, and left rear wheel. The position of the front wheel block can be adjusted according to the front and rear wheel track of the aircraft. The front wheel block, right rear wheel block, and left rear wheel block have the same structural shape.

5. The aircraft center of gravity measuring device according to claim 4, characterized in that: The loading platform is a square flat plate. A hemispherical support point is welded to each of the four corners of the platform's bottom. The projection points of the centers of these four hemispherical support points onto the top of the loading platform are sequentially connected and marked with scales. The lines connecting the four projection points are parallel to the four edges of the loading platform, front, back, left, and right. The projection point on the left front end of the loading platform is the origin of the coordinate system. The line parallel to the front side of the loading platform is the X-axis scale line, and the line parallel to the left side of the loading platform is the Z-axis scale line. The distance between adjacent hemispherical support points is L. A column is welded to each of the two corners of the left front and rear rear faces of the loading platform, and the loading platform is perpendicular to the columns. A long, narrow bolt hole is located on the middle of the front side of the top of the loading platform, facing rearward, for connecting the front wheel stops. This long bolt hole is used to install and adjust the position of the front wheel stops.

6. The aircraft center of gravity measuring device according to claim 1, characterized in that: Roller I is a bearing structure composed of multiple cylinders, including roller II, frame and shaft. There are multiple roller II, all of which are cylindrical structures. Multiple roller II are set in the frame through the shaft. Roller I can roll to reduce the friction between the loading platform and foundation I and foundation II.

7. The aircraft center of gravity measuring device according to claim 1, characterized in that: The upper surfaces of both foundation I and foundation II are parallel to the loading platform and form a certain angle with the horizontal plane. The lower surfaces are both flat. Both foundation I and foundation II are provided with bosses to restrict the slippage of roller I. One end of each of the two foundation columns is fixed to the boss of foundation I by bolts.

8. The aircraft center of gravity measuring device according to claim 1, characterized in that: Foundation I and Foundation II have the same structure, and the total height of Foundation II is greater than that of Foundation I.

9. The aircraft center of gravity measuring device according to claim 1, characterized in that: Two columns are welded to the front and rear corners of the left side of the loading platform, respectively, and are perpendicular to the loading platform. The center of the spherical groove at the lower left end of the column is on the same plane as the upper surface of the loading platform. The distance between the spherical groove at the upper left end and the spherical groove at the lower left end of the same column is L. The distance between the spherical grooves at the upper left end of different columns and the distance between the spherical grooves at the lower left end of different columns are both L.

10. The aircraft center of gravity measuring device according to claim 1, characterized in that: The ball bearings are spherical and installed in the spherical groove of the column. The ball bearings can roll relative to the spherical groove of the column to reduce the friction between the column and the foundation column.

11. The aircraft center of gravity measuring device according to claim 1, characterized in that: The foundation columns are parallel to each other and are all perpendicular to the upper surface of foundation I.

12. The aircraft center of gravity measuring device according to claim 1, characterized in that: The measuring plate is a thin steel plate, and the resistance value of the resistance strain gauge is proportional to the load on the measuring plate.

13. The aircraft center of gravity measuring device according to claim 1, characterized in that: The range of a pressure sensor is directly proportional to the stiffness of the spring.

14. The aircraft center of gravity measuring device according to claim 1, characterized in that: Both the upper and lower shells are cylindrical structures, and the outer diameter of the upper shell matches the inner diameter of the lower shell. Both the upper and lower shells are supported by springs, upper load blocks, and lower load blocks.

15. A method of using the aircraft center of gravity measuring device as described in any one of claims 1 to 14, characterized in that: The method includes: Tow the aircraft onto the cargo platform to the stop. When towing the aircraft onto the cargo platform, the left and right rear wheels of the aircraft need to be in full contact with the left and right rear wheel guards. This will make the aircraft's coordinate system parallel to the cargo platform's coordinate system. Adjust the position of the front wheel guard to contact the aircraft's front wheels to fix the aircraft. The coordinates of the aircraft wheels on the cargo platform can be measured by using graduated lines on the platform. ,0, ); Read the voltmeter readings from the measurement circuit. The circuit reads the X-coordinate voltmeter voltage value (UX), the Z-coordinate voltmeter voltage value (UZ), and the Y-coordinate voltmeter voltage value (UY) respectively. Calculate the aircraft's center of gravity coordinates as follows: , , Since the distance between support points L and the power supply voltage U are fixed values, therefore Since it is a constant, simply changing the dial of the voltmeter allows direct reading of the aircraft's center of gravity coordinates via the measuring circuit. The resulting center of gravity coordinates are relative to the platform's coordinate system, while the coordinates relative to the aircraft's wheels are: , and This means obtaining the coordinates of the aircraft's center of gravity relative to the wheels.

Images