Unmanned aerial vehicle gravity center measuring device
By using a three-point suspension measurement method and the principle of torque balance, combined with a quick-folding gantry and moving wheels, the problem of inaccurate drone center of gravity measurement was solved, enabling efficient and accurate center of gravity measurement for large-volume drones and adapting to the measurement needs of drones of different sizes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHONGHANG ELECTRONIC MEASURING INSTR (XIAN) CO LTD
- Filing Date
- 2025-05-20
- Publication Date
- 2026-05-05
AI Technical Summary
Existing UAV center of gravity measurement devices are inaccurate when measuring the Z-axis center of gravity, especially for large-volume UAVs. Furthermore, traditional methods are cumbersome to operate and cannot meet the accuracy requirements of rocket booster launches.
The three-point suspension measurement method is adopted. By using load cells and tilt sensors at three measurement points A, B, and C, combined with the torque balance principle, the center of gravity coordinates of the UAV in horizontal and tilted states are measured. The accurate measurement of the UAV's center of gravity is achieved by using a quick-folding gantry and moving wheels.
It enables high-precision measurement of the center of gravity of UAVs, especially large-volume UAVs, simplifies the operation process, improves the accuracy and efficiency of measurement, and adapts to the measurement needs of UAVs of different sizes.
Smart Images
Figure CN224202647U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of UAV center of gravity measurement technology, and relates to a UAV center of gravity measurement device. Background Technology
[0002] Currently, with the advancement of science and technology, drones have been widely used in both military and civilian fields, playing an increasingly important role and gradually becoming a pillar industry of the national economy. Drones generally take off using rocket-assisted launch, runway launch, or catapult launch methods. Rocket-assisted launch, with its high maneuverability and strong site adaptability, has gradually become a common method for drone launches. In this method, the drone is launched via a rocket booster, and the booster rocket automatically detaches from the drone after burning out. The axis of the connection between the booster rocket and the drone launch interface is the rocket's thrust line. To ensure launch safety and the drone's flight trajectory, the distance between the rocket's thrust line and the drone's center of gravity must be controlled within a certain range. Therefore, before launch, the drone's actual center of gravity needs to be measured, and the thrust line or center of gravity position adjusted so that the thrust line passes as close as possible to the drone's center of gravity.
[0003] Traditional UAV center of gravity measurement devices mostly only provide measurements of the center of gravity coordinates along the X and Y axes in the horizontal plane. For methods that can measure the Z-axis center of gravity coordinates, flip-type and lifting-type measurements are the most common. Flip-type measurements require rotating the UAV 90 degrees to measure the Z-axis center of gravity position, similar to measuring the horizontal center of gravity. This method is difficult for UAVs with large wingspans. Lift-type measurements are affected by manufacturing and assembly errors. When measuring the center of gravity of different UAVs, the position of the lifting point of the measuring device often needs to be adjusted. The adjustment process is relatively cumbersome and prone to generating lateral loads, leading to inaccurate Z-axis center of gravity measurements. Utility Model Content
[0004] The purpose of this invention is to solve the problems of inaccurate measurement of the center of gravity of UAVs and difficulty in measuring the center of gravity of large-volume UAVs in the Z direction by existing measurement methods, and to provide a UAV center of gravity measurement device.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A drone center of gravity measuring device includes a measuring fixture, which has measuring points A, B and C, and is used to place the drone to be measured.
[0007] Measurement points B and C are both located near one end of the measuring fixture, while measurement point A is located near the other end of the measuring fixture. Measurement points B and C are arranged in a straight line, while measurement points A, B, and C are arranged in a triangular shape.
[0008] Each of the three measurement points, A, B, and C, is equipped with a corresponding lifting unit, and each lifting unit is equipped with a weighing sensor. A tilt sensor is also installed at measurement point A.
[0009] The further improvement of this utility model is as follows:
[0010] The A measurement point is set in several places, and the A measurement points are distributed in a straight line from the end of the measuring fixture towards the B measurement point and the C measurement point.
[0011] The lifting units at measurement points B and C include a quick-folding gantry frame at points BC, on which lifting devices at points B and C are distributed at intervals.
[0012] Both the lifting device at point B and the lifting device at point C are equipped with weighing sensors;
[0013] The lifting device at point B is connected at one end to the quick-folding gantry frame at point BC, and at the other end to the measurement point B.
[0014] The lifting device at point C is connected at one end to the quick-folding gantry frame at points BC, and at the other end to the measuring point C.
[0015] The lifting unit at measurement point A includes a quick-folding gantry frame at point A, a lifting device at point A is installed on the quick-folding gantry frame at point A, and a weighing sensor is installed on the lifting device at point A.
[0016] One end of the quick-folding gantry frame at point A is connected to the quick-folding gantry frame at point A, and the other end is connected to measurement point A.
[0017] Both the quick-folding gantry frames at points B and C and the quick-folding gantry frame at point A are equipped with casters at their bottoms.
[0018] The BC-point quick-folding gantry includes a crossbeam, with support beams at both ends of the crossbeam.
[0019] The crossbeam and the support beam are hinged.
[0020] Eye bolts are installed at measurement points A, B, and C, and these eye bolts are connected to the corresponding lifting devices.
[0021] The eye bolts are all connected to the corresponding lifting devices via load cell hook attachments, and the load cells are mounted on the corresponding load cell hook attachments.
[0022] There are 3 measurement points A.
[0023] Compared with the prior art, the present invention has the following beneficial effects:
[0024] This utility model discloses a drone center of gravity measurement device. The measuring fixture includes measurement points A, B, and C, which are arranged in a triangle. The three points work together to measure the drone. When the three measurement points can be kept at the same height, the tension at each measurement point is measured when the drone is in a horizontal state. By adjusting the height of measurement point A, the center of gravity position can be measured at different tilt angles. Based on these values, a tilt sensor is installed on the measuring fixture to measure the tilt angle of the drone, providing tilt angle data for calculating the drone's center of gravity position. The result of the drone's center of gravity measurement is then obtained through subsequent calculations. Compared with single-point suspension measurement and flip measurement, the three-point suspension measurement method of this utility model allows for autonomous control of the drone's tilt angle, and the tilt angle is relatively small. It can measure larger drones, and the measurement process is relatively simple. Furthermore, because the three-point suspension measurement method uses a lifting measurement method, the lifting frame can move freely, resulting in relatively small lateral force influence and more accurate drone center of gravity position measurement results. This provides more accurate measurement data for adjusting the drone's center of gravity or thrust line.
[0025] Furthermore, in this invention, there are several measurement points A, with multiple lifting point positions. For small drones, by moving the lifting point positions, the same tilt angle can be achieved with a shorter lifting distance, thus achieving the purpose of rapid measurement.
[0026] Furthermore, in this invention, both the BC-point quick-folding gantry and the A-point quick-folding gantry are equipped with casters at their bottoms. The A-point quick-folding gantry moves freely. As the testing fixture and the drone gradually change from a horizontal to an inclined state, the A-point quick-folding gantry automatically finds the direction of the plumb bob under the action of lateral force, so that the force axis of the A-point weighing sensor is in the direction of the plumb bob, thereby obtaining a relatively accurate A-point tension and providing accurate data for calculating the actual center of gravity of the drone. Attached Figure Description
[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a three-dimensional schematic diagram of the device of this utility model and the drone installed horizontally.
[0029] Figure 2 This is a three-dimensional schematic diagram of the tensile force measuring component of this utility model.
[0030] Figure 3 This is a three-dimensional schematic diagram of the test fixture and the drone in a horizontal position according to this utility model.
[0031] Figure 4 This is a top view of the UAV of this utility model when calculating the X and Y coordinates of the center of gravity in a horizontal state.
[0032] Figure 5 This is the front view of the UAV of this invention when calculating the Z-coordinate of the center of gravity under tilted conditions.
[0033] Figure 6 This is a schematic diagram of the folded state of the quick-folding gantry frame of this utility model (where a is a folded perspective view; b is a folded side view; c is a folded top view).
[0034] In the diagram, 1-BC point is the quick-folding gantry frame; 2-B point is the lifting device; 3-B point is the load cell; 4-B point is the eye bolt; 5-UAV; 6-C point is the eye bolt; 7-C point is the load cell; 8-C point is the lifting device; 9-Measuring fixture; 10-Tilt sensor; 11-A point is the eye bolt; 12-A point is the quick-folding gantry frame; 13-A point is the lifting device; 14-A point is the load cell; 15-Measuring fixture lifting point M; 16-Measuring fixture lifting point N; 17-Load cell hook accessory; 18-Load cell. Detailed Implementation
[0035] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0037] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0038] In the description of the embodiments of this utility model, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use, they are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the utility model. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0039] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0040] In the description of the embodiments of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0041] The present invention will now be described in further detail with reference to the accompanying drawings:
[0042] See Figures 1 to 6 This utility model discloses a device for measuring the center of gravity of a drone. By adjusting the drone's horizontal and tilted attitudes, it can measure the center of gravity coordinates of the drone's X, Y, and Z axes. Compared with traditional measurement methods, this method is more convenient to operate and provides more accurate measurement results.
[0043] Specifically, it includes the following structure:
[0044] See Figure 1 A drone center of gravity measurement device includes a measuring fixture 9, which has measuring points A, B, and C. The measuring fixture 9 is used to place the drone to be measured. Measuring points B and C are located at one end of the measuring fixture 9, and measuring point A is located at the other end of the measuring fixture 9. Measuring points B and C are arranged in a straight line, while measuring points A, B, and C are arranged in a triangle. Each measuring point A, B, and C is equipped with a corresponding lifting unit, and each lifting unit is equipped with a weighing sensor. An angle sensor 10 is installed at measuring point A.
[0045] See Figure 2 Weighing sensor hook accessories 17 are provided above and below the weighing sensor 18. The weighing sensor hook accessory 17 above the weighing sensor 18 is used to connect to measurement point A, and the weighing sensor hook accessory 17 below the weighing sensor 18 is used to connect to the corresponding lifting device, specifically:
[0046] Measurement points A, B, and C are respectively connected to the load cell hook attachment 17 below the load cell 14 at point A, the load cell 3 at point B, and the load cell 7 at point C via eye bolt 11 at point A, eye bolt 4 at point B, and eye bolt 6 at point C.
[0047] Weighing sensor 14 at point A, weighing sensor 3 at point B, and weighing sensor 7 at point C are connected to lifting device 13 at point A, lifting device 2 at point B, and lifting device 8 at point C respectively via weighing sensor hook attachment 17 above them.
[0048] Among them, lifting device 2 at point B and lifting device 8 at point C are connected to the quick-folding gantry frame 1 at point BC, and lifting device 1 at point A is connected to the quick-folding gantry frame 12 at point A.
[0049] During measurement, the horizontal and tilt states of the UAV 5 can be switched by changing the lifting height of lifting device 13 at point A, lifting device 2 at point B, and lifting device 8 at point C. The tilt sensor 10 is installed at the front end of the test fixture 9 to measure the horizontality and tilt angle of the UAV 5. Lifting device 13 at point A can be manually or electrically operated. By controlling the difference in lifting height between lifting device 13 at point A, lifting device 2 at point B, and lifting device 8 at point C, different tilt angles of the UAV 5 can be achieved.
[0050] Furthermore, the front end of the testing fixture 9 has two spare lifting points to accommodate the lifting and measurement of drones of different sizes. By switching the position of lifting point A to either lifting point M15 or lifting point N16 of the measuring fixture, different lifting point spacing parameters can be achieved to accommodate drones 5 of different sizes. For smaller drones, by moving the position of lifting point A, the same tilt angle can be achieved with a shorter lifting distance, thus achieving the purpose of rapid measurement.
[0051] In this device, the lifting mechanism is installed on the lifting frame and can be lifted manually or electrically to achieve rapid horizontal or tilting of the drone. By adjusting the lifting height of the drone's nose lifting point, the center of gravity position can be measured at different tilt angles.
[0052] Furthermore, the load cell 14 at point A, the load cell 3 at point B, the load cell 7 at point C, and the tilt sensor 10 can all transmit measurement data in real time via wired or wireless means, enabling real-time measurement of the actual center of gravity position of the UAV 5. During measurement, the measurement data is sent to the controller (including industrial control computer, etc.), and the controller can calculate the current center of gravity coordinates of the UAV in real time through the built-in calculation program.
[0053] Furthermore, both the BC-point quick-folding gantry 1 and the A-point quick-folding gantry 12 are equipped with casters at their bottoms, enabling free movement. During the transition from a horizontal to an inclined state, the quick-folding gantry can automatically adjust its position to adapt to changes in the spacing between the lifting points. Specifically, as the test fixture 9 and the drone 5 gradually transition from a horizontal to an inclined state, the A-point quick-folding gantry 12 automatically finds the direction of the plumb bob under the action of lateral force, ensuring that the force axis of the A-point weighing sensor 14 is in the direction of the plumb bob, thereby obtaining a relatively accurate tension at A-point and providing accurate data for calculating the actual center of gravity position of the drone 5.
[0054] Furthermore, the measuring fixture 9 has multiple sets of UAV mounting interfaces. The UAV 5 is connected to the measuring fixture 9 through different mounting interfaces, and the position of the UAV relative to measuring points A, B, and C can be adjusted.
[0055] This invention measures the center of gravity of a drone using a three-point suspension method. The drone is fixed to a measuring fixture, and the tension at each of the three suspension points is measured in both horizontal and tilted states. (The tension generated by the weight of the measuring fixture at each of the three suspension points remains unchanged under the same tilt; the tension generated by the drone's weight is obtained by subtracting the weight of the measuring fixture from the total tension.) The tilt angle is also measured. Based on the principle of torque balance, the drone's center of gravity is calculated. Compared to single-point suspension and flipping measurements, the three-point suspension method of this invention allows for autonomous control of the drone's tilt angle (adjustable from 0 to 20 degrees) and a relatively small tilt angle, enabling the measurement of larger drones. The measurement process is also relatively simple. Furthermore, because this three-point suspension method uses a lifting measurement method, the lifting frame can move freely, resulting in less lateral force influence and more accurate measurement results for the drone's center of gravity, providing more accurate measurement data for adjusting the drone's center of gravity or thrust line.
[0056] Furthermore, the gantry frame in the measuring device disclosed in this embodiment includes a top crossbeam and support beams at both ends of the crossbeam. The crossbeam and support beams can be connected by a hinge, and the bottom of the support beams can be supported by two points. The two-point support beams can also be connected by a hinge, enabling the entire device to be foldable. See [link to documentation]. Figure 6It enables rapid deployment and retrieval of measuring devices outdoors, thus improving the mobility of the measuring devices.
[0057] Furthermore, during measurement, the height of the measuring device can be adjusted to meet the measurement needs of drones of different sizes, thus broadening the applicability of the measuring device.
[0058] This utility model also discloses a method for measuring the center of gravity of an unmanned aerial vehicle (UAV), including the following steps:
[0059] After powering on the equipment, before installing the drone 5, measure the tension at points A, B, and C of the measuring fixture 9 in both horizontal and tilted states, and calibrate the measuring device. After completing the calibration of the measuring fixture, install the drone 5 onto the measuring fixture 9.
[0060] like Figure 1 As shown, the test fixture 9 is lifted to a horizontal position using lifting device 13 at point A, lifting device 2 at point B, and lifting device 8 at point C; Figure 4 As shown, by observing the output value of the tilt sensor 10, it is confirmed that the UAV 5 is in a horizontal state. Weighing sensors 14 at point A, 3 at point B, and 7 at point C measure the tension F at the three suspension points A, B, and C respectively under horizontal conditions. A1 F B1 F C1 .
[0061] Lifting devices 2 at point B and 8 at point C remain stationary. Lifting device 13 at point A is used to raise the test fixture 9 to an inclined position. Figure 5 As shown, load cell 14 at point A, load cell 3 at point B, and load cell 7 at point C measure the tension F at the three suspension points A, B, and C respectively under inclined conditions. A2 F B2 F C2 Meanwhile, the tilt sensor 10 measures the tilt angle α at this time.
[0062] like Figure 3 As shown, the line connecting lifting points B and C of measuring fixture 9 is taken as the y-axis, and the direction pointing from the line connecting lifting points B and C to lifting point B is the positive direction of the y-axis. Lifting point A is located on the perpendicular bisector of the line connecting lifting points B and C. The perpendicular bisector of the line connecting lifting points B and C is taken as the x-axis, and the direction pointing from the perpendicular bisector to lifting point A is the positive direction of the x-axis. The midpoint of the line connecting lifting points B and C is the origin O, and the positive direction of the z-axis is the direction perpendicular to the xOy plane from the origin O.
[0063] like Figure 3 and Figure 4 As shown, in the horizontal state, within the xOz plane, according to the principle of torque balance, the tension F at lifting point A is... A1The torque about point O is equal to the torque of gravity G1 about point O, from which the actual center of gravity coordinate x of the UAV along the X-axis can be obtained. G Calculation formula:
[0064]
[0065] Where a represents the distance from measurement point A to the origin O;
[0066] like Figure 3 , Figure 4 In the yOz plane, according to the principle of torque balance, the tension F at lifting points B and C is... B1 F C1 The sum of the moment vectors about point O is equal to the moment of gravity G1 about point O, from which the actual centroid coordinates y of the UAV's Y-axis can be obtained. G Calculation formula:
[0067]
[0068] Where b represents the distance between measurement points B and C;
[0069] like Figure 5 As shown, in the xOz plane under inclined conditions, according to the principle of torque balance, the tension F at the suspension point A under inclined conditions is... A2 The torque about point O is equal to the torque of gravity G2 about point O, from which the actual center of gravity coordinate z of the UAV's Z-axis can be obtained. G Calculation formula:
[0070]
[0071] The calculation formula is built into the calculation program, which can measure the tension F at the three suspension points A, B, and C in a horizontal state. A1 F B1 F C1 And the tension F at the three suspension points A, B, and C in the tilted state. A2 F B2 F C2 By using the tilt angle α, the actual X, Y, and Z axis coordinates of the UAV 5 can be quickly calculated. By comparing the deviation between the actual and designed center-of-gravity coordinates of the UAV 5, and given the known position of the counterweight, the accurate weight of the required counterweight can be quickly calculated. Then, based on this accurate weight, the UAV is ballasted, ensuring that the actual center-of-gravity coordinates after ballast match the ideal designed coordinates. This avoids multiple blind ballasting operations, saves time, and improves the efficiency of ballasting operations.
[0072] In this embodiment, the design center refers to the center-of-gravity coordinates of the ideal standard of the designed drone.
[0073] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A device for measuring the center of gravity of an unmanned aerial vehicle (UAV), characterized in that, The measuring fixture (9) includes a measuring point A, a measuring point B and a measuring point C, and the measuring fixture (9) is used to place the UAV to be measured. The measurement points B and C are both located at one end close to the measuring fixture (9), and the measurement point A is located at the other end close to the measuring fixture (9). The measurement points B and C are arranged in a straight line, and the measurement points A, B and C are arranged in a triangular shape. Each of the measurement points A, B, and C is equipped with a corresponding lifting unit, and each lifting unit is equipped with a weighing sensor. An angle sensor (10) is installed at the measurement point A.
2. The UAV center of gravity measuring device according to claim 1, characterized in that, The A measurement point is set in several places. The A measurement points are arranged in a straight line from the end of the measuring fixture (9) towards the B measurement point and the C measurement point.
3. The UAV center of gravity measuring device according to claim 1, characterized in that, The lifting units at measurement points B and C include a quick-folding gantry frame (1) at point BC, on which lifting devices (2) at point B and lifting devices (8) at point C are distributed at intervals. Weighing sensors are installed on both the lifting device (2) at point B and the lifting device (8) at point C; The lifting device (2) at point B is connected at one end to the quick-folding gantry frame (1) at point BC, and at the other end to the measuring point B; The lifting device (8) at point C is connected at one end to the quick-folding gantry frame (1) at point BC, and at the other end to the measuring point C.
4. The UAV center of gravity measuring device according to claim 3, characterized in that, The lifting unit at measurement point A includes a quick-folding gantry frame (12) at point A, a lifting device (13) at point A is provided on the quick-folding gantry frame (12), and a weighing sensor is provided on the lifting device (13). One end of the quick-folding gantry frame (12) at point A is connected to the quick-folding gantry frame (12) at point A, and the other end is connected to the measurement point A.
5. The UAV center of gravity measuring device according to claim 4, characterized in that, Both the quick-folding gantry frame (1) at point BC and the quick-folding gantry frame (12) at point A are equipped with casters at their bottoms.
6. The UAV center of gravity measuring device according to claim 5, characterized in that, The BC point quick-folding gantry (1) includes a crossbeam, with support beams at both ends of the crossbeam.
7. The UAV center of gravity measuring device according to claim 6, characterized in that, The crossbeam and the support beam are hinged.
8. The UAV center of gravity measuring device according to claim 4, characterized in that, Eye bolts are installed at measurement points A, B, and C, and these eye bolts are connected to the corresponding lifting devices.
9. The UAV center of gravity measuring device according to claim 8, characterized in that, The lifting eye bolts are all connected to the corresponding lifting devices through the weighing sensor hook attachment (17), and the weighing sensors are set on the corresponding weighing sensor hook attachment (17).
10. The UAV center of gravity measuring device according to claim 2, characterized in that, There are 3 measurement points A.