A device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle

Abstract

This invention belongs to the field of UAV center of gravity measurement technology, specifically a device for measuring the center of gravity of multi-rotor UAVs. The device includes a base, a vertical tube welded to the top outer wall of the base, and a lead screw installed inside the vertical tube. An internally threaded tube is screwed onto the outer wall of the lead screw, and a cross-shaped connecting block is welded to the outer wall of the internally threaded tube. A sliding sleeve is welded to the outer wall of the cross-shaped connecting block. A top sleeve is fixedly installed on the top outer wall of the vertical tube via a flange, and equidistantly distributed fixing rods are welded around the perimeter of the vertical tube's side walls. This invention, through the combination of an adjustable support structure and an adaptive sensing module, can adapt to multi-rotor UAVs with different wheelbases. Combined with automatic center of gravity calculation and real-time display, it significantly improves measurement accuracy, versatility, and debugging efficiency, reducing human error. The overall structure uses lead screw linkage and linkage transmission, along with horizontal calibration and scale calibration, to achieve precise adjustment of support spacing and height, resulting in strong measurement stability.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) center of gravity measurement technology, and more particularly to a device for measuring the center of gravity of a multi-rotor UAV. Background Technology

[0002] Multirotor drones, with their advantages of simple structure, flexible operation, and convenient takeoff and landing, are widely used in many fields such as aerial surveying, power line inspection, logistics transportation, and emergency rescue. Their flight stability and control accuracy directly depend on the rationality of the aircraft's center of gravity. As a core parameter of the drone's mechanical characteristics, the center of gravity directly affects the accuracy of attitude closed-loop control, hovering stability, wind resistance, and endurance. It is a key indicator that must be accurately measured and calibrated during assembly, debugging, and modification. After the multirotor drone is assembled, the propellers are installed, and the battery and onboard equipment are arranged, the center of gravity must be detected and adjusted to ensure that it coincides with the geometric center. This avoids problems such as fuselage tilting, uneven motor load, increased power consumption, delayed control response, and even crashes caused by a shift in the center of gravity. Therefore, an efficient, accurate, and adaptable center of gravity measurement device is crucial for drone research and development and production.

[0003] Existing multi-rotor UAV center of gravity measurement equipment generally suffers from drawbacks such as poor adaptability, low measurement accuracy, cumbersome operation, and insufficient data visualization.

[0004] First, traditional devices are mostly fixed-axis structures, which cannot be adapted to multi-rotor models of different sizes and arm spans, resulting in poor versatility. Some devices lack adaptive support structures, and stress concentration or unstable contact can easily occur when the drone is placed, leading to distorted pressure acquisition.

[0005] In addition, the measurement process relies on manual reading and calculation, which is inefficient and has large errors. Furthermore, the lack of a horizontal calibration mechanism and a real-time data display module makes on-site debugging difficult and makes it hard to quickly determine the direction and amount of the center of gravity offset. This fails to meet the actual needs of mass production and rapid debugging, thus restricting the assembly quality and debugging efficiency of the UAV. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle, which overcomes the shortcomings of the prior art and effectively solves the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle includes a base, a vertical tube welded to the top outer wall of the base, a lead screw installed inside the vertical tube, an internally threaded tube screwed onto the outer wall of the lead screw, a cross-shaped connecting block welded onto the outer wall of the internally threaded tube, a sliding sleeve welded onto the outer wall of the cross-shaped connecting block, a top sleeve fixedly installed on the top outer wall of the vertical tube by a flange, and fixing rods evenly distributed around the perimeter of the side wall of the vertical tube, a sleeve slidably fitted onto the outer wall of the fixing rod, and a connecting rod hinged between the sleeve and the sliding sleeve;

[0009] A positioning sleeve is screwed to the inner wall of one end of the sleeve, and a universal ball is provided on the inner wall of the positioning sleeve. A pressure sensor is installed on the top outer wall of the universal ball, and a buffer pad is installed on the top outer wall of the pressure sensor.

[0010] Preferably, the sliding sleeve and the vertical tube are in sliding fit, and the outer wall of the vertical tube is provided with equally spaced sliding grooves, and the cross connecting block is disposed through the inner wall of the sliding groove.

[0011] Preferably, an anti-slip pad is adhered to the top outer wall of the buffer pad.

[0012] Preferably, the positioning sleeve has a ball groove inside, and the ball groove rotates in conjunction with the universal ball.

[0013] Preferably, a ball bearing is installed on the inner wall of the top of the top sleeve, and the lead screw is rotatably connected to the inner wall of the top sleeve through the ball bearing, and a handwheel is installed on the outer wall of the top of the lead screw.

[0014] Preferably, a vertical scale line is provided on one side of the outer wall of the vertical tube, and a horizontal scale line is provided on the top outer wall of the fixing rod.

[0015] Preferably, a clamp is fixedly installed on the top of the outer wall of the vertical pipe, and an OLED display screen is installed on one side of the outer wall of the clamp.

[0016] Preferably, a level bubble is installed on the top outer wall of the base, and screws evenly distributed are screwed to the top outer wall of the base, with a support pad welded to the bottom outer wall of the screws.

[0017] The beneficial effects of this invention are as follows:

[0018] 1. The device for measuring the center of gravity of a multi-rotor UAV of the present invention combines an adjustable support structure with an adaptive sensing module, which can be adapted to multi-rotor UAVs with different wheelbases. With automatic center of gravity calculation and real-time display, it significantly improves measurement accuracy, versatility and debugging efficiency, and reduces human operation error. The overall structure adopts lead screw linkage and linkage transmission, combined with horizontal calibration and scale calibration, to achieve precise adjustment of support spacing and height, and strong measurement stability.

[0019] 2. The device for measuring the center of gravity of a multi-rotor UAV of the present invention consists of a base, a vertical tube, a lead screw, an internally threaded tube, a sliding sleeve, a fixed rod, a sleeve, and a connecting rod forming a linkage adjustment mechanism. By rotating the handwheel, multiple sets of support points can be extended and retracted synchronously, quickly matching the span of the UAV arm. The adjustment process has high synchronization, and the scale lines allow for intuitive reading of dimensions. It is compatible with different models of UAVs, greatly improving the versatility of the device.

[0020] 3. The device for measuring the center of gravity of a multi-rotor UAV of the present invention forms an adaptive support and pressure acquisition unit through a positioning sleeve, a universal ball, a pressure sensor, a buffer pad and an anti-slip pad. The universal ball can rotate freely to fit the bottom of the fuselage to avoid stress interference. Combined with an OLED display screen to display the force value and center of gravity coordinates in real time, the measurement data is accurate and intuitive, and the center of gravity offset state can be quickly determined to meet the requirements of high precision and rapid debugging. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of a device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle (UAV) proposed in this invention. Figure 1 ;

[0022] Figure 2 This is a schematic diagram of the overall structure of a device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle (UAV) proposed in this invention. Figure 2 ;

[0023] Figure 3 This is a schematic diagram of the vertical tube connection structure of a device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle (UAV) proposed in this invention.

[0024] Figure 4 This is a schematic diagram of the internal structure of the vertical tube of a device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle (UAV) proposed in this invention.

[0025] Figure 5 This is a schematic diagram of the positioning sleeve connection structure of a device for measuring the center of gravity of a multi-rotor UAV proposed in this invention;

[0026] Figure 6 This is a schematic diagram of the disassembled structure of the positioning sleeve and gimbal ball of a device for measuring the center of gravity of a multi-rotor UAV proposed in this invention;

[0027] Figure 7 This is a control system distribution diagram of a device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle (UAV) proposed in this invention.

[0028] Figure 8 This is a schematic diagram of the circuit hardware structure of a device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle (UAV) proposed in this invention.

[0029] Figure 9 This is a circuit diagram of the control system for a device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle (UAV) proposed in this invention.

[0030] In the diagram: 1. Base; 2. Vertical tube; 3. Lead screw; 4. Internally threaded tube; 5. Cross connector; 6. Sliding sleeve; 7. Top sleeve; 8. Fixing rod; 9. Sleeve; 10. Connecting rod; 11. Positioning sleeve; 12. Universal ball; 13. Pressure sensor; 14. Buffer pad; 15. Anti-slip pad; 16. Ball groove; 17. Ball bearing; 18. Handwheel; 19. Sliding groove; 20. Vertical scale line; 21. Horizontal scale line; 22. Clamp; 23. OLED display screen; 24. Level bubble; 25. Screw; 26. Support pad. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0032] Reference Figures 1-9 Example 1: A device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle (UAV) includes a base 1, a vertical tube 2 welded to the top outer wall of the base 1, a lead screw 3 inside the vertical tube 2, an internally threaded tube 4 screwed onto the outer wall of the lead screw 3, a cross connecting block 5 welded to the outer wall of the internally threaded tube 4, a sliding sleeve 6 welded to the outer wall of the cross connecting block 5, a top sleeve 7 fixedly installed on the top outer wall of the vertical tube 2 via a flange, and fixing rods 8 evenly distributed around the periphery of the side wall of the vertical tube 2, a sleeve 9 slidably sleeved on the outer wall of the fixing rod 8, and a connecting rod 10 hinged between the sleeve 9 and the sliding sleeve 6.

[0033] The above scheme uses the rotation of the lead screw 3 as the power input to drive the internal threaded tube 4, the cross connecting block 5 and the sliding sleeve 6 to move up and down synchronously. Then, the connecting rod 10 pushes the sleeve 9 to move radially along the fixed rod 8, realizing the synchronous adjustment of the support span of multiple support points. It can quickly match multi-rotor UAVs with different arm lengths and wheelbase specifications, greatly improving the applicability and versatility of the device, meeting the needs of multiple UAV models to share a single device for measurement, and reducing debugging costs and equipment space occupation.

[0034] In this embodiment, a linkage adjustment mechanism is formed by the base 1, vertical tube 2, lead screw 3, internal threaded tube 4, sliding sleeve 6, fixed rod 8, sleeve 9 and connecting rod 10. Rotating the handwheel 18 can synchronously drive the extension and retraction of multiple support points, quickly match the span of the drone arm, and the adjustment process has high synchronization. The scale lines 20 and 21 can be read intuitively, adapting to different models and greatly improving the versatility of the device.

[0035] In the second embodiment, a positioning sleeve 11 is screwed onto the inner wall of one end of the sleeve 9, and a universal ball 12 is provided on the inner wall of the positioning sleeve 11. A pressure sensor 13 is installed on the top outer wall of the universal ball 12, and a buffer pad 14 is installed on the top outer wall of the pressure sensor 13. A clamp 22 is fixedly installed on the top of the outer wall of the vertical pipe 2, and an OLED display screen 23 is installed on one side of the outer wall of the clamp 22.

[0036] Through the above solution, the pressure sensor 13 can achieve adaptive angle adjustment under the action of the omnidirectional ball 12, perfectly fitting the curved surface of the bottom of the drone and the inclined mounting surface, avoiding additional stress and measurement deviation caused by rigid support. At the same time, the buffer pad 14 can effectively absorb the impact of placement, protecting the drone shell and sensor components. The OLED display screen 23 can display the pressure data and center of gravity calculation results in real time, making the measurement status clear at a glance, improving measurement efficiency and debugging intuitiveness.

[0037] In this embodiment, an adaptive support and pressure acquisition unit is formed by positioning sleeve 11, universal ball 12, pressure sensor 13, buffer pad 14 and anti-slip pad 15. Universal ball 12 can rotate freely to fit the bottom of the machine body to avoid stress interference. With the OLED display screen 23, the force value and center of gravity coordinates are displayed in real time. The measurement data is accurate and intuitive, and the center of gravity offset state can be quickly determined to meet the high-precision and rapid debugging requirements.

[0038] The sliding sleeve 6 and the vertical tube 2 are in sliding fit. The outer wall of the vertical tube 2 is provided with equally spaced sliding grooves 19, and the cross connecting block 5 is provided through the inner wall of the sliding groove 19.

[0039] Through the above scheme, the slide groove 19 forms a limiting guide for the cross connecting block 5, ensuring that the slide sleeve 6 can only move linearly up and down along the vertical tube 2 and will not rotate circumferentially, thus ensuring the stability and reliability of the transmission structure, avoiding jamming and stuck phenomena, improving the adjustment accuracy and service life of the mechanism, and ensuring the stability of long-term use.

[0040] The top outer wall of the cushioning pad 14 is bonded with an anti-slip pad 15.

[0041] Through the above solution, the anti-slip pad 15 can significantly increase the friction coefficient with the contact surface of the drone body, prevent the drone body from slipping, shaking or tipping over during the measurement process, improve placement safety and measurement stability, avoid data distortion caused by displacement, and ensure accurate and reliable center of gravity calculation results.

[0042] The positioning sleeve 11 has a ball groove 16 inside, and the ball groove 16 rotates with the universal ball 12.

[0043] Through the above scheme, the ball groove 16 provides sufficient rotation space and support for the universal ball 12, ensuring that the universal ball 12 can rotate flexibly in any direction, realize full-angle self-adaptation of the support point, eliminate errors caused by installation stress and poor contact, and make the pressure acquisition closer to the real stress state.

[0044] A ball bearing 17 is installed on the inner wall of the top sleeve 7, and the lead screw 3 is rotatably connected to the inner wall of the top sleeve 7 through the ball bearing 17. A handwheel 18 is installed on the outer wall of the top of the lead screw 3.

[0045] Through the above solution, the ball bearing 17 significantly reduces the frictional resistance when the lead screw 3 rotates, making the handwheel 18 easier and less strenuous to adjust, with higher rotational accuracy. It can achieve minute and fine adjustments to the support height and span, meeting the adjustment requirements of high-precision measurement.

[0046] A vertical scale line 20 is provided on one side of the outer wall of the vertical tube 2, and a horizontal scale line 21 is provided on the top outer wall of the fixing rod 8.

[0047] With the above scheme, the vertical scale line 20 and the horizontal scale line 21 can intuitively display the adjustment distance and support dimensions, making it convenient for operators to quickly locate the target wheelbase and height, realize quantitative adjustment, and improve the consistency of debugging and the repeatability of measurement.

[0048] A level bubble 24 is installed on the top outer wall of the base 1, and screws 25 distributed at equal intervals are screwed onto the top outer wall of the base 1. A support pad 26 is welded to the bottom outer wall of the screws 25.

[0049] The above scheme allows for the rapid determination of the device's baseline level by using the bubble level 24, and multi-point independent leveling by rotating the screw 25, eliminating systematic errors caused by uneven ground, ensuring a consistent measurement baseline, and improving overall measurement accuracy.

[0050] Example 3: Engineering Center of Gravity Calculation Process

[0051] 1. Establish a coordinate system

[0052] With the geometric center of the device as the origin O(0,0), the coordinates of the four force sensors are as follows:

[0053] Top: (0, +L), Bottom: (0, -L), Right: (+L, 0), Left: (-L, 0).

[0054] 2. Sensor calibration and force conversion

[0055] For each sensor i, perform the following: Fi = Ki * (rawi - offseti)

[0056] Where rawi is the HX711 source code, offseti is the tare zero point, and Ki is the scaling factor (N / count or g / count).

[0057] 3. Calculate the total load

[0058] Wtotal = F_top + F_bottom + F_right + F_left

[0059] If Wtotal < Wmin, then the measurement is deemed invalid.

[0060] 4. Calculate the coordinates of the centroid.

[0061] Xcog = ((F_right - F_left) / Wtotal) * L

[0062] Ycog = ((F_top - F_bottom) / Wtotal) * L

[0063] 5. Only judge the bias

[0064] RatioX = (F_right - F_left) / Wtotal

[0065] RatioY = (F_top - F_bottom) / Wtotal

[0066] RatioX and RatioY are approximately in the range [-1, 1].

[0067] 6. Bias Judgment

[0068] Let the threshold T be:

[0069] - RatioX > +T: skew to the right; RatioX < -T: skew to the left; otherwise, center X.

[0070] - RatioY > +T: skew upwards; RatioY < -T: skew downwards; otherwise, center Y.

[0071] The final output can be a 9-grid layout: center / top / bottom / left / right / top left / top right / bottom left / bottom right.

[0072] The above solution enables the controller to automatically complete the entire process of data acquisition, calibration, calculation, and judgment without manual calculation or table lookup. It directly outputs the center of gravity coordinates and offset azimuth, with fast measurement speed, high accuracy, and intuitive results. This can significantly shorten the assembly and debugging cycle of UAVs and is suitable for mass production and rapid on-site testing.

[0073] Working principle: Before use, adjust the device to a horizontal state using the level bubble 24 and screw 25 on the base 1 to ensure accurate measurement reference. According to the wheelbase size of the UAV, turn the handwheel 18 to drive the lead screw 3 to rotate, so that the internal thread tube 4 and the sliding sleeve 6 rise and fall along the vertical tube 2. Through the connecting rod 10, push the sleeve 9 to move horizontally along the fixed rod 8. Adjust the support span to the matching size with reference to the horizontal scale line 21.

[0074] The drone is placed on four anti-slip pads 15, with the buffer pads 14 and omnidirectional balls 12 adaptively fitting the bottom of the drone body to ensure that the pressure sensor 13 is evenly stressed. The pressure sensor 13 collects four pressure signals and transmits them to the STC32G12K128 controller. The controller performs calibration, total load calculation, center of gravity coordinate calculation and offset judgment processes, and sends the force value, center of gravity coordinate and offset status to the OLED display screen 23 in real time. The operator judges the center of gravity position based on the displayed data and corrects it by adjusting the drone battery and equipment installation position. The measurement is repeated until the center of gravity meets the standard, thus completing the rapid measurement and debugging of the center of gravity of the multi-rotor drone.

[0075] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle, comprising a base (1), characterized in that, The base (1) has a vertical tube (2) welded to the top outer wall, and a screw rod (3) is installed inside the vertical tube (2). An internal threaded tube (4) is screwed onto the outer wall of the screw rod (3), and a cross connecting block (5) is welded onto the outer wall of the internal threaded tube (4). A sliding sleeve (6) is welded onto the outer wall of the cross connecting block (5). A top sleeve (7) is fixedly installed on the top outer wall of the vertical tube (2) through a flange. Fixed rods (8) are welded at equal intervals around the side wall of the vertical tube (2). A sleeve (9) is slidably sleeved on the outer wall of the fixed rod (8), and a connecting rod (10) is hinged between the sleeve (9) and the sliding sleeve (6). A positioning sleeve (11) is screwed onto the inner wall of one end of the sleeve (9), and a universal ball (12) is provided on the inner wall of the positioning sleeve (11). A pressure sensor (13) is installed on the top outer wall of the universal ball (12), and a buffer pad (14) is installed on the top outer wall of the pressure sensor (13).

2. The device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle according to claim 1, characterized in that, The sliding sleeve (6) and the vertical tube (2) are in sliding fit. The outer wall of the vertical tube (2) is provided with equally spaced sliding grooves (19), and the cross connecting block (5) is provided through the inner wall of the sliding groove (19).

3. The device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle according to claim 1, characterized in that, An anti-slip pad (15) is adhered to the top outer wall of the buffer pad (14).

4. The device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle according to claim 1, characterized in that, The positioning sleeve (11) has a ball groove (16) inside, and the ball groove (16) rotates with the universal ball (12).

5. The device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle according to claim 1, characterized in that, The top inner wall of the top sleeve (7) is equipped with a ball bearing (17), and the lead screw (3) is rotatably connected to the inner wall of the top sleeve (7) through the ball bearing (17). A handwheel (18) is installed on the top outer wall of the lead screw (3).

6. The device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle according to claim 1, characterized in that, The outer wall of one side of the vertical tube (2) is provided with a vertical scale line (20), and the outer wall of the top of the fixing rod (8) is provided with a horizontal scale line (21).

7. The device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle according to claim 1, characterized in that, A clamp (22) is fixedly installed on the top of the outer wall of the vertical pipe (2), and an OLED display screen (23) is installed on one side of the outer wall of the clamp (22).

8. The device for measuring the center of gravity of a multi-rotor unmanned aerial vehicle according to claim 1, characterized in that, A level bubble (24) is installed on the top outer wall of the base (1), and screws (25) are screwed to the top outer wall of the base (1) at equal intervals. A support pad (26) is welded to the bottom outer wall of the screws (25).

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