An unmanned aerial vehicle automatic moving and center of mass measurement cooperative operation system and method

Abstract

The application relates to an unmanned aerial vehicle (UAV) automatic transfer and center of mass measurement collaborative operation system and method, and belongs to the field of UAV center of mass measurement. The system is integrated in a UAV pulsation production line and is used for realizing automatic transfer and center of mass measurement collaborative operation of the UAV. The collaborative operation system comprises a transfer unit, a center of mass measurement unit and a production line control system. The transfer unit is used for transferring the UAV between an assembly rack and the center of mass measurement unit. The center of mass measurement unit is used for measuring the center of mass of the UAV loaded thereon. The production line control system serves as a general controller and is used for controlling the transfer unit to transfer the UAV, controlling the center of mass measurement unit to measure the center of mass of the UAV and coordinating the time sequence of the movement of the transfer unit and the measurement of the center of mass measurement unit. The application realizes full-automatic closed-loop operation of UAV transfer and center of mass measurement, and solves the problems of existing UAV center of mass measurement, such as dependence on manual hoisting, long operation time, high human intervention and low integration degree with the pulsation production line.

Description

Technical Field

[0001] This invention relates to the field of UAV center of mass measurement, specifically to a collaborative system and method for automated transfer and center of mass measurement of UAVs, which is integrated into a UAV pulsed production line to realize the collaborative operation of automated transfer and center of mass measurement of UAVs. Background Technology

[0002] During the drone manufacturing process, it is necessary to measure the drone's center of gravity, which is generally achieved using a crane scale or a dedicated mass measurement platform. Currently, the standard method for measuring the center of gravity in drone production involves workers using a crane to lift the drone from the assembly stand to a center of gravity measuring device. This method has the following problems: First, the lifting process requires multiple people and is time-consuming, with each transfer taking approximately 30 minutes. Second, after lifting, manual adjustment of the drone's clamping position on the measuring device is required (to secure the drone to the tooling on the testing platform), further extending the measurement cycle. Third, the entire measurement process requires multiple interventions by operators (lifting, leveling, and disassembling), making automated continuous operation impossible. Fourth, there is a lack of timing coordination between the lifting and measurement operations, resulting in long downtime and low utilization of the measuring equipment.

[0003] As drone production moves towards pulsed and mass production, there is an urgent need for a collaborative operation system and method that can seamlessly integrate transfer and measurement, reduce manual intervention, shorten measurement cycle time, and achieve fully automated closed-loop operation. Summary of the Invention

[0004] The technical problem to be solved: To avoid the shortcomings of existing technologies, this invention provides a collaborative system and method for automated transfer and center of gravity measurement of unmanned aerial vehicles (UAVs), which solves the problems of existing technologies such as UAV center of gravity measurement relying on manual hoisting, long operation time, excessive manual intervention, and low integration with pulsed production lines.

[0005] The technical solution of this invention is: a collaborative operation system for automated transfer and center of gravity measurement of unmanned aerial vehicles (UAVs), comprising a transfer unit, a center of gravity measurement unit, and a production line control system; wherein: The transfer unit is used for transferring the UAV between the assembly bench and the centroid measurement unit; The center of mass measurement unit is used to measure the center of mass of the UAV mounted on it; The production line control system is connected to the transfer unit and the center of mass measurement unit respectively. It is used to control the transfer unit to transfer the UAV, control the center of mass measurement unit to measure the center of mass of the UAV, and coordinate the timing of the movement of the transfer unit and the measurement of the center of mass measurement unit. The production line control system is also connected to the workshop-level MES system to obtain the model of the UAV under test and the corresponding transfer control parameters and measurement process parameters from the MES system.

[0006] A further technical solution of the present invention is: the transfer unit includes two ground rails and four transfer actuators. The four transfer actuators are divided into two groups, each group is slidably installed on one ground rail, and the two groups of transfer actuators are arranged facing each other to support the four support points at the bottom of the UAV. The transfer actuator has three-dimensional spatial motion functions in the horizontal X-axis, horizontal Y-axis, and vertical Z-axis. The ground rail provides a horizontal X-axis moving track for the transfer actuator. Multiple transfer actuators are differentially or synchronously controlled in the horizontal X-axis through the production line control system. The horizontal Y-axis output end of the transfer actuator is equipped with a gripper, which is used to support the support point of the UAV.

[0007] A further technical solution of the present invention is: the center of mass measurement unit includes a bearing fixture, a weighing sensor, a tilting mechanism, and a positioning detection sensor; wherein: The tilting mechanism is mounted on the measurement platform and is used to drive the UAV to roll around its heading axis; The support fixture is installed on the tilting mechanism, which is used to position and install the drone, and rotates with the drone under the drive of the tilting mechanism; The load cells are installed at the bottom of the tilting mechanism. There are three load cells, one in front and two in the back, arranged in an isosceles triangle. The load cell at the vertex of the isosceles triangle is located directly below the drone's heading axis. The load cells are used to collect weight information measured at the sensor's location under different attitudes of the drone. The positioning detection sensor is mounted on the support fixture and is used to detect whether the drone is placed in the correct position on the support fixture; The weighing sensor and the positioning detection sensor are both connected to the production line control system to transmit their respective measurement data to the production line control system for processing; the power source of the tilting mechanism is a servo motor, which is electrically connected to and controlled by the production line control system.

[0008] A further technical solution of the present invention is: the servo motor of the tilting mechanism is equipped with an encoder, which is used to obtain the real-time roll angle of the UAV and feed it back to the production line control system to form a closed-loop control for the roll angle adjustment of the UAV.

[0009] A method for automated transfer and centroid measurement coordination of unmanned aerial vehicles (UAVs), the method comprising: Step 1. Transport the assembly stand carrying the drone to be tested to the transfer preparation position using an AGV transport vehicle; Step 2. The production line control system obtains the transfer control parameters and center of gravity measurement process parameters corresponding to the model of the UAV under test. Based on the transfer control parameters, it controls each transfer actuator of the transfer unit to lift the UAV from the assembly table and move it along the ground rail to the set position on the bearing fixture of the center of gravity measurement unit. Step 3. The position information of the UAV positioning point is obtained by the positioning detection sensor of the centroid measurement unit and fed back to the production line control system to determine whether the UAV is in position. If it is in position, the UAV and the supporting tooling are fixedly connected. If it is not in position, the production line control system controls each transfer actuator to readjust the position of the UAV until it is in position, and then the UAV and the supporting tooling are fixedly connected.

[0010] Step 4. The production line control system sends a center of gravity measurement command to the center of gravity measurement unit according to the measurement process parameters. The center of gravity measurement unit drives the UAV to rotate sequentially to the horizontal, forward roll and reverse roll attitudes. In each attitude, it collects data from each weighing sensor and feeds it back to the production line control system. The production line control system calculates the spatial coordinates of the center of gravity based on the torque balance equation and records the results. Step 5. After the centroid spatial coordinate measurement is completed, the fixed connection between the drone and the supporting tooling is removed. The production line control system controls each transfer actuator to transfer the drone back to the assembly stand at the initial position, completing one cycle of centroid measurement.

[0011] A further technical solution of the present invention is: the transfer preparation position is located between two ground rails and close to the starting end of the ground rails; when the assembly stand carrying the UAV arrives at the transfer preparation position, each transfer actuator is symmetrically located on both sides of the UAV, and each transfer actuator is in the initial state, in which the transfer actuator is located at the starting end of the ground rail, and the Y-axis is retracted and the Z-axis is in the lowest position.

[0012] A further technical solution of the present invention is: the transfer control parameters include the X-axis stroke, Y-axis extension length and Z-axis lifting height of each transfer actuator; the measurement process parameters of the center of gravity include the roll angle, stabilization time and zero-point compensation coordinates when measuring the center of gravity of the UAV.

[0013] A further technical solution of the present invention is: when the production line control system controls each transfer actuator to readjust the position of the drone more than a set number of times and still fails to achieve the desired position, the production line control system triggers an emergency interruption and issues an alarm signal to await manual intervention and adjustment.

[0014] A further technical solution of the present invention is: when collecting data from each weighing sensor in each posture, the posture is maintained for a set stabilization time before data collection is performed. The stabilization time is 10-30 seconds to eliminate the influence of inertia.

[0015] A further technical solution of the present invention is: a method for calculating the spatial coordinates of the centroid based on the torque balance equation in a production line control system includes: The formula for calculating the mass of a drone and its centroid in the X direction is: (1) (2) (3) In the formula, Let P1 be the weight of the drone; denote the weight sensor located at the vertex of the isosceles triangle arrangement as P1, and the weight sensors located at the two endpoints of the base as P2 and P3. The reading of sensor P1 is given when the drone's roll angle is 0 degrees. The reading of sensor P2 is given when the drone's roll angle is 0 degrees. The reading of sensor P3 when the drone's roll angle is 0 degrees; The distance in the X direction from the center of mass of the UAV to sensor P1; The distance in the X direction from sensor P1 to sensors P2 and P3; The distance from the drone's center of mass to the drone's test baseline. The distance from the UAV test reference to the test instrument reference of the centroid measurement equipment. The distance in the X direction from the test instrument reference to sensor P1 is the heading; The formulas for calculating the centroid of a UAV in the Y and Z directions are: (4) (5) In the formula, Let Y be the position of the centroid of the UAV in the Y direction. Let α be the position of the UAV's center of mass in the Z direction, and α be the UAV's roll angle. This is the reading of sensor P2 when the UAV rolls at an angle of +α. This is the reading of sensor P2 when the UAV rolls at an angle of -α. This is the reading of sensor P3 when the UAV rolls at an angle of +α. This is the reading of sensor P3 when the UAV rolls at an angle of -α. This is the distance from the centerline to sensor P2. This is the distance from the centerline to sensor P3.

[0016] The beneficial effects of this invention are as follows: A collaborative system and method for automated transfer and center of mass measurement of unmanned aerial vehicles (UAVs) achieves fully automated closed-loop operation from assembly stand to measurement and return through the coordinated control of the transfer unit and the center of mass measurement unit. The transfer and docking process requires no manual intervention, and the measurement cycle time is greatly shortened. At the same time, the system has on-site detection, retry mechanism and emergency interruption function. In abnormal situations, it can automatically alarm and wait for processing, effectively avoiding equipment damage and safety accidents. The entire process adopts closed-loop control of servo motors, and the product centering, clamping and measurement accuracy far exceeds that of manual hoisting and platform scale measurement methods. In addition, the system is deeply integrated with the MES system, which can automatically call process parameters, and the measurement data is automatically uploaded and bound to the UAV's product serial number, realizing full traceability of quality data.

[0017] Each transfer actuator of the transfer unit of the present invention can be independently controlled along the X direction of the ground track, and can achieve synchronous or differential motion to adapt to the support point span of different models of UAVs, and is applicable to the transfer of multiple models of UAVs.

[0018] By combining the in-place detection sensor with the production line control system, it is possible to detect whether the drone is placed in the mounting fixture. The production line control system can also control the various transfer actuators to adjust the drone's position, thereby improving the test clamping accuracy and saving centering adjustment and clamping time.

[0019] The tilting mechanism allows for precise adjustment of the drone's roll angle, achieving an angle control accuracy of ±0.01°. This invention, through roll angle adjustment for measuring the drone's center of gravity, allows the drone to rotate only around its longitudinal axis (e.g., ±30°), keeping the center of gravity height almost constant. This avoids the problems of pitch-based measurements where overall tilting leads to a higher center of gravity and a greater risk of tipping over, making it particularly suitable for large-mass or slender drones. This invention's roll method for testing the drone's center of gravity establishes a system of simultaneous equations using eccentric sensor readings at two different roll angles (e.g., +α and -α). The differential measurement principle directly eliminates systematic errors such as blade eccentricity and sensor zero-point drift. This ensures that the calculated Y-axis and Z-axis center of gravity primarily depend on the repeatability of the roll angle and the linearity of the sensor, rather than on precise calibration of the absolute position. The error propagation chain is extremely short, thus significantly improving the accuracy of center of gravity measurement.

[0020] This invention effectively solves the problems of existing technologies, such as reliance on manual hoisting for UAV center of gravity measurement, long operation time, excessive manual intervention, and low integration with pulsed production lines. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall layout of an automated transfer and centroid measurement collaborative operation system for unmanned aerial vehicles (UAVs) according to the present invention. Figure 2 A diagram illustrating the system's composition and the flow of materials and information; Figure 3 This is a flowchart of the UAV automated transfer and centroid measurement collaborative operation method of the present invention; Figure 4 This is a schematic diagram of the three-axis independent motion function of the transfer actuator in the transfer unit of the present invention; Figure 5 This is a schematic diagram of the UAV being mounted on the centroid measurement unit in this invention; Figure 6 Schematic diagram of the principle for testing the mass and centroid of a drone in the X direction; Figure 7 This is a schematic diagram of the measurement of the UAV at the roll angle of 0 degrees during the center of mass test (i.e., the horizontal attitude of the UAV). Figure 8 This is a schematic diagram showing the measurement of the UAV at a roll angle of +30 degrees during the center of mass test. Figure 9 This is a schematic diagram of the measurement of the UAV at a roll angle of -30 degrees during the center of mass test.

[0023] In the diagram: 100-Transfer unit, 200-Center of mass measurement unit, 300-Production line control system, 400-Assembly stand, 500-Drone under test, 101-Transfer actuator X-axis, 102-Transfer actuator Y-axis, 103-Transfer actuator Z-axis, 201-Measuring platform of measuring equipment, 202-Bearing fixture, 203-Weighing sensor, 204-Tilting mechanism, 205-Positioning detection sensor. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 An embodiment of the UAV automated transfer and centroid measurement collaborative operation system of the present invention, such as... Figure 1 As shown, the system includes a transfer unit 100, a center of mass measurement unit 200, and a production line control system 300. The UAV 500 to be tested is placed on the assembly stand 400 and transported to the transfer preparation position of the collaborative operation system by an AGV transport vehicle. The collaborative operation system automatically transfers the UAV 500 to the center of mass measurement unit 200 for center of mass position measurement. The entire process is automatically controlled by the production line control system 300.

[0026] The transfer unit 100 is used for transferring the UAV 500 between the assembly stand 400 and the center of mass measurement unit 200. In this embodiment, the transfer unit 100 includes two ground rails and four transfer actuators. The four transfer actuators are divided into two groups, with two transfer actuators in each group slidably mounted on one ground rail. The two groups of transfer actuators are arranged facing each other, corresponding to the four support points on both sides of the bottom of the UAV 500. Each of the four transfer actuators is independently controlled by the production line control system 300 and has independent three-dimensional spatial movement capabilities.

[0027] See also Figure 4 The transfer actuator has three-dimensional spatial motion capabilities in the horizontal X-axis, horizontal Y-axis, and vertical Z-axis, corresponding to... Figure 4 The transfer actuators shown are X-axis 101, Y-axis 102, and Z-axis 103. X-axis 101 is the ground rail, providing a horizontal X-axis movement track for the transfer actuators. In this embodiment, the transfer actuators use motor-driven sliders that slide along the guide rail. The motors, serving as the power source for movement in all directions, are electrically connected to the production line control system 300, which controls their operation. The four transfer actuators achieve differential or synchronous movement on the horizontal X-axis ground rail through servo synchronous control technology. A gripper is provided at the horizontal Y-axis output end of the transfer actuators to support the support points of the UAV 500. The X-axis differential movement of the transfer actuators is used to match the X-axis span of the support points of different UAV models 500, while the X-axis synchronous movement enables the four transfer actuators to synchronously transfer the UAV 500 along the ground rail. The Y-axis and Z-axis movements of the transfer actuator can also be controlled synchronously or differentially to ensure that the gripper can support the corresponding support points on the bottom surface of the UAV and that the UAV 500 is in a horizontal position. In other embodiments, the specific mechanical structure of the transfer unit 100 can be implemented in various ways, as long as it can achieve the above-mentioned three-axis independent movement function.

[0028] The center-of-gravity measurement unit is used to measure the center of gravity of the UAV 500 mounted on it. (See also...) Figure 1 , Figure 5The center of mass measurement unit includes a bearing fixture 202, a weighing sensor 203, a tilting mechanism 204, and a positioning detection sensor 205.

[0029] Specifically, the tilt mechanism 204 is mounted on the measurement platform 201 of the center of mass measurement equipment. The tilt mechanism 204 drives the UAV under test 500 to roll around its heading axis. The tilt mechanism 204 utilizes an existing mechanical device with an axis-based deflection function. Its power source is a servo motor, which is electrically connected to and controlled by the production line control system 300. The servo motor of the tilt mechanism 204 has a built-in encoder for real-time feedback of the angle position, ensuring an attitude adjustment accuracy of ±0.01°. To balance clamping safety and measurement accuracy, the roll angle range of the tilt mechanism 204 is set to ±40°, meeting the measurement requirements for both forward and reverse rolls of the UAV 500. Through joint calculation of the left and right roll attitudes, the accuracy of the UAV's center of mass measurement in the altitude direction can be effectively improved.

[0030] The support fixture 202 is fixedly mounted on the upper surface of the tilting mechanism 204. The support fixture 202 is used for positioning and mounting the drone 500. The support fixture 202 rotates around the drone's yaw axis under the drive of the tilting mechanism 204. The support fixture 202 is equipped with a positioning structure (such as a positioning pin or positioning groove) to ensure the repeatability of the drone 500's placement position. The support fixture 202 is quick-changeable, allowing for rapid replacement with suitable fixtures according to different drone models.

[0031] Weighing sensors 203 are installed at the bottom of the tilting mechanism 204. Three weighing sensors 203 are arranged in a horizontal isosceles triangle, one in front and two behind. The weighing sensor 203 at the vertex of the isosceles triangle is directly below the UAV's heading axis. The weighing sensors 203 are used to collect weight information measured at their respective locations under different attitudes of the UAV 500. Each weighing sensor 203 is communicatively connected to the production line control system 300, used to feed the collected data back to the system for processing. The data measured by the weighing sensor 203 is the weight of the UAV 500 after removing its gross weight (i.e., removing the weight of the tilting mechanism 204 and the supporting fixture 202).

[0032] The weighing range of the load cell 203 can be configured as needed, such as selecting 400kg, 400kg, or 600kg specifications. The accuracy class of the sensor is selected as 0.03% of the full scale to meet the accuracy requirements for measuring the overall machine mass and center of gravity.

[0033] A positioning detection sensor 205 is mounted on the support fixture 202. The positioning detection sensor 205 is used to detect whether the drone is properly positioned on the support fixture 202. Specifically, the positioning detection sensor 205 is a laser rangefinder sensor, used to measure the distance between the drone 500 and the corresponding positioning surface on the support fixture 202. The positioning detection sensor 205 is communicatively connected to the production line control system 300, used to feed back the collected distance data to the production line control system 300 for judgment processing. The production line control system 300 determines whether the drone 500 is properly positioned by comparing it with the theoretical distance. If the determination is correct, the drone 500 can be manually fixed to the support fixture 202. If the determination is incorrect, the production line control system 300 uses a through-hole control transfer unit 100 to adjust the position of the drone 500. In other embodiments, the positioning detection sensor 205 can also be a proximity switch.

[0034] The production line control system 300 serves as the control core, communicating with the transfer unit 100, the centroid measurement unit 200, and the workshop-level MES system. The production line control system 300 includes a transfer control module and a measurement coordination module. The transfer control module controls the timing and synchronization of the movement of each transfer actuator in the transfer unit 100, while the measurement coordination module sends measurement commands to the centroid measurement unit 200, receives measurement results, and coordinates the action timing with the transfer control module. The production line control system 300 obtains the model parameters of the UAV 500 under test from the MES system and automatically calls the corresponding transfer control parameters and measurement process parameters. The transfer control parameters are used to achieve precise transfer of the UAV under test, and the measurement process parameters are used for centroid coordinate measurement. The production line control system 300, in conjunction with the transfer unit 100 and the centroid measurement unit 200, achieves a fully automated closed-loop operation from the assembly stand 400 to the measurement station and back to the assembly stand 400.

[0035] The production line control system 300 also has an emergency handling function: when the positioning detection sensor 205 detects that the drone 500 is not placed in place or is not aligned, the control system 300 controls the transfer unit 100 to readjust the position and place it again, repeating the attempt no more than a set number of times; if the requirements are still not met after exceeding the set number of times, the system triggers an emergency interruption, issues an audible and visual alarm signal, displays fault information on the operation interface, and waits for manual intervention.

[0036] The production line control system 300 automatically calls the transfer control parameters and measurement process parameters corresponding to the UAV model based on the production task instructions received from the MES system. The transfer control parameters are the X-axis stroke, Y-axis extension length, and Z-axis lifting height of each transfer actuator determined according to the UAV model and its support points. The measurement process parameters are the roll angle, stabilization time, and zero-point compensation coordinates during center of gravity measurement determined according to the UAV model. (The stabilization time is the time after the tilting mechanism 204 drives the UAV to tilt to the set roll angle and maintains that stabilization time before reading the measurement data from the weighing sensor 203 to eliminate inertial effects; the zero-point compensation coordinates are...) Figure 6 In the calculation of the centroid L0, the zero point is different for different UAVs after clamping. The measured centroid coordinates are relative to the zero point of the nose. Therefore, zero-point compensation coordinates are needed in the centroid calculation.

[0037] In use, the transport trolley delivers the assembly stand 400 carrying the UAV 500 to be tested to the initial position area of ​​the transfer unit 100. The production line control system 300 controls each transfer actuator of the transfer unit 100 to grab the UAV 500 and automatically transfer it to the center of gravity measurement unit 200. After the detection is in place, the UAV 500 is manually fixed. The production line control system 300 sends a measurement command to the center of gravity measurement unit 200 and calculates the center of gravity coordinates of the UAV 500 to be tested based on the data measured by each weighing sensor 203 in the center of gravity measurement unit 200.

[0038] Example 2 This embodiment provides a method for coordinated automated transfer and center of gravity measurement using a UAV, which is implemented using the coordinated automated transfer and center of gravity measurement system described in Embodiment 1. Specifically, as... Figure 1 , Figure 3 , Figures 6-9 As shown, the method includes the following steps: Step 1. Product placement: An AGV transport vehicle carries an assembly stand 400 containing the UAV 500 to be tested to a transfer preparation position. The transfer preparation position is located between two ground rails, near the starting end of the ground rails. The production line control system 300 sends a standby command to the transfer unit 100. When the assembly stand 400 arrives at the transfer preparation position, each transfer actuator is symmetrically positioned on both sides of the UAV 500 and is in its initial state. In the initial state, the transfer actuators are located at the starting end of the ground rails, the Y-axis is retracted, and the Z-axis is in its lowest position.

[0039] Step 2. Automated Transfer: The production line control system 300 obtains the model parameters of the UAV 500 under test from the MAS system, automatically calls the transfer control parameters and center of gravity measurement process parameters corresponding to the model (the transfer control parameters include the X-axis stroke, Y-axis extension length and Z-axis lifting height of each transfer actuator; the center of gravity measurement process parameters include the roll angle, stabilization time and zero-point compensation coordinates when measuring the center of gravity of the UAV, etc.), and sends a transfer command to the transfer unit 100. According to the transfer control parameters, the transfer unit controls each transfer actuator to lift the UAV 500 from the assembly table 400 and move it along the ground rail to the set position on the bearing fixture 202 of the center of gravity measurement unit 200.

[0040] Specifically, each transfer actuator in the transfer unit 100 determines the support point information of the UAV according to the transfer control parameters. It then independently moves along the X-axis to below the designated support point, extends its gripper along the Y-axis to below the UAV 500, and then synchronously rises along the Z-axis to lift the UAV 500, separating it from the assembly stand 400. After being lifted to a safe height, each transfer actuator synchronously moves along the X-axis, transferring the UAV 500 above the bearing fixture 202 of the center of mass measurement unit 200, and then synchronously descends along the Z-axis, smoothly placing the UAV 500 on the bearing fixture 202. The positioning structure on the bearing fixture 202 cooperates with the UAV 500 to achieve initial positioning.

[0041] Step 3. Positioning Detection and Locking: The positioning information of the UAV 500 is obtained by the positioning detection sensor 205 of the centroid measurement unit 200 and fed back to the production line control system 300 to determine whether the UAV 500 is in position. If it is in position, the UAV 500 and the carrier fixture 202 are fixedly connected. If it is not in position, the production line control system 300 controls each transfer actuator to readjust the position of the UAV 500 until it is in position, and then fixes the UAV 500 and the carrier fixture 202. If the production line control system 300 controls each transfer actuator to readjust the position of the UAV more than a set number of times and it is still not in position, the production line control system 300 triggers an emergency interruption and issues an alarm signal to wait for manual intervention.

[0042] Specifically, the positioning detection sensor 205 on the support fixture 202 detects whether the drone 500 is placed in place and aligned. The parameters detected include: the gap between the drone 500 and the positioning surface of the support fixture 202, the coaxiality deviation between the positioning hole on the drone 500 and the positioning pin on the support fixture 202, and the pressure distribution between the bottom surface of the drone 500 and the contact surface of the support fixture 202.

[0043] If the device is detected to be in place and aligned (with all deviation values ​​less than the set thresholds), the production line control system 300 will issue a prompt (such as a buzzer or the operation interface displaying "Placement in place, please lock"), and the operator will manually install the positioning pin and connecting nut to fix the drone 500 to the carrier fixture 202. After the production line control system 300 confirms the locking status through the positioning detection sensor 205, it will proceed to the next step.

[0044] If the detection is incomplete or misaligned, the production line control system 300 controls the transfer unit 100 to readjust its position and place it again. Adjustment includes fine-tuning the X, Y, or Z-axis position of the transfer actuator to align the drone 500 with the positioning structure on the carrier fixture 202 until the detected deviation is less than a set threshold. The attempts are repeated no more than a set number, set to 3 in this example. If the requirements are still not met after exceeding the set number of attempts, the production line control system 300 triggers an emergency interruption: issuing an audible and visual alarm signal, displaying the fault message "Drone not placed correctly, please intervene manually" on the operation interface, stopping subsequent operations, and awaiting operator intervention. The operator can restore system operation or terminate the operation by manually controlling or adjusting the system.

[0045] Step 4. Centroid Measurement: Based on the acquired center of gravity measurement process parameters, the production line control system sends a center of gravity measurement command to the center of gravity measurement unit 200. The center of gravity measurement unit 200 drives the UAV 500 to rotate sequentially to horizontal, forward roll and reverse roll postures. In each posture, it collects data from each weighing sensor 203 and feeds it back to the production line control system 300. The production line control system 300 calculates and records the spatial coordinates of the center of gravity based on the torque balance equation.

[0046] Specifically, after the UAV 500 is positioned, detected, and locked, the production line control system 300 sends a measurement command to the centroid measurement unit 200. The centroid measurement unit 200 automatically executes the following measurement process: (1) The tilting mechanism 204 adjusts the bearing fixture 202 to a horizontal position (i.e., the roll angle is 0°), maintains the stability time (set to 10 seconds in this example) to eliminate the inertial effect, and collects data from the three weighing sensors 203.

[0047] (2) The tilting mechanism 204 tilts to the left to the set angle (in this example, the roll angle is +30°), and after maintaining stability for 10 seconds, the data of the three weighing sensors 203 are collected.

[0048] (3) After the tilting mechanism 204 returns to the horizontal position, it tilts to the right to the set angle (in this example, the roll angle is -30°). After maintaining the stability for 10 seconds, the data of the three weighing sensors 203 are collected.

[0049] The tilting mechanism 204 adopts closed-loop control of servo motor, and the roll angle is fed back in real time through encoder to ensure that the attitude adjustment accuracy reaches ±0.01°.

[0050] The control system of the centroid measurement unit 200 calculates the centroid coordinates based on the joint solution of the torque balance equations: In a horizontal orientation, using the readings of three weighing sensors 203 and the known coordinates of each sensor relative to the origin of the equipment coordinate system, a torque balance equation is established, and the X-axis coordinate Xc of the center of mass in the horizontal plane is calculated.

[0051] Specifically, such as Figure 6 , Figure 7 As shown, Figure 6 The measuring frame shows the tilting mechanism 204 and the supporting tooling 202 assembly. The formula for calculating the mass of the UAV and its center of mass in the X direction is: (1) (2) (3) In the formula, Let P1 be the weight of the drone; denote the weight sensor located at the vertex of the isosceles triangle arrangement as P1, and the weight sensors located at the two endpoints of the base as P2 and P3. The reading of sensor P1 is given when the drone's roll angle is 0 degrees. The reading of sensor P2 is given when the drone's roll angle is 0 degrees. The reading of sensor P3 when the drone's roll angle is 0 degrees; The distance in the X direction from the center of mass of the UAV to sensor P1; The distance in the X direction from sensor P1 to sensors P2 and P3; The distance from the drone's center of mass to the drone's test baseline (the drone test baseline is...). Figure 6 (As shown at the end of the machine head) The distance from the UAV test reference to the test instrument reference of the centroid measurement equipment ( That is, zero-point compensation coordinates, with the nose end of the drone as the zero point of the test reference. The zero point is different for different drones after clamping, and the measured centroid coordinates are relative to the zero point of the nose. The distance in the X direction from the test instrument reference to sensor P1 is the distance in the heading.

[0052] Under both forward and reverse roll postures, torque balance equations were established, and the Y-axis and Z-axis coordinates (Yc, Zc) of the center of mass were simultaneously solved. By jointly solving the left and right roll postures, the accuracy of the center of mass measurement in the height Z-axis and horizontal Y-axis was effectively improved.

[0053] Specifically, such as Figures 7-9 As shown, based on the principle of static moment equilibrium, we can obtain the following system of equations:

[0054]

[0055]

[0056] Solving the system of equations, we obtain the formulas for calculating the centroid of the UAV in the Y and Z directions: (4) (5) In the formula, Let Y be the position of the centroid of the UAV in the Y direction. Let α be the position of the UAV's center of mass in the Z direction, and α be the UAV's roll angle. The distance between the centers of the two load cells 203 at the bottom edge of the drone's axis. This is the reading of sensor P2 when the UAV rolls at an angle of +α. This is the reading of sensor P2 when the UAV rolls at an angle of -α. This is the reading of sensor P3 when the UAV rolls at an angle of +α. This is the reading of sensor P3 when the UAV rolls at an angle of -α. Let P2 be the distance from the midline between the two bottom sensors. This is the distance from the midline of the two bottom sensors to sensor P3.

[0057] After the calculation is completed, the centroid spatial coordinates (Xc, Yc, Zc) of the UAV 500 measured in this test are obtained. The production line control system 300 records and stores the centroid spatial coordinate information, binds it with the serial number of the UAV 500 being measured, and uploads it to the quality database of the MES system to form the quality file of the UAV 500, realizing full traceability of quality data.

[0058] Step 5. Return to forwarding: After the centroid spatial coordinate measurement is completed, the fixed connection between the UAV 500 and the supporting tooling 202 is removed. The production line control system 300 controls each transfer actuator to transfer the UAV 500 back to the assembly stand 400 at the initial position, completing one cycle of centroid measurement. The transfer actuators of the transfer unit 100 return to the standby state.

[0059] Specifically, after the production line control system 300 completes the centroid coordinate calculation, it displays a measurement completion message on the operation interface. The operator manually removes the positioning pins and connecting nuts, confirming that the drone 500 and the supporting fixture 202 are unlocked and safely removed. The production line control system 300 sends a return command to the transfer unit 100. Each transfer actuator of the transfer unit 100 extends along the Y-axis to below the drone 500, then simultaneously rises along the Z-axis to lift the drone 500, separating it from the supporting fixture 202. Then, it simultaneously moves along the X-axis, transporting the drone 500 from above the supporting fixture 202 back to above the assembly stand 400, and then simultaneously descends along the Z-axis, smoothly placing the drone 500 on the assembly stand 400. After completion, each transfer actuator retracts along the Y-axis and returns to the standby state. The AGV then transfers the assembly stand 400 carrying the drone 500 to the next station, achieving continuous flow on the pulsed production line.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A collaborative system for automated transfer and centroid measurement of unmanned aerial vehicles (UAVs), characterized in that, include: Transfer unit, center of mass measurement unit, and production line control system; among which: The transfer unit is used for transferring the UAV between the assembly bench and the centroid measurement unit; The center of mass measurement unit is used to measure the center of mass of the UAV mounted on it; The production line control system is connected to the transfer unit and the center of mass measurement unit respectively. It is used to control the transfer unit to transfer the UAV, control the center of mass measurement unit to measure the center of mass of the UAV, and coordinate the timing of the movement of the transfer unit and the measurement of the center of mass measurement unit. The production line control system is also connected to the workshop-level MES system to obtain the model of the UAV under test and the corresponding transfer control parameters and measurement process parameters from the MES system.

2. The UAV automated transfer and centroid measurement collaborative operation system according to claim 1, characterized in that, The transfer unit includes two ground rails and four transfer actuators. The four transfer actuators are divided into two groups, each group is slidably installed on one ground rail, and the two groups of transfer actuators are arranged facing each other, corresponding to the four support points on the bottom of the drone. The transfer actuator has three-dimensional spatial motion functions in the horizontal X-axis, horizontal Y-axis, and vertical Z-axis. The ground rail provides a horizontal X-axis moving track for the transfer actuator. Multiple transfer actuators are differentially or synchronously controlled in the horizontal X-axis through the production line control system. The horizontal Y-axis output end of the transfer actuator is equipped with a gripper, which is used to support the support point of the UAV.

3. The UAV automated transfer and centroid measurement collaborative operation system according to claim 1, characterized in that, The centroid measurement unit includes a bearing fixture, a weighing sensor, a tilting mechanism, and a positioning detection sensor; wherein: The tilting mechanism is mounted on the measurement platform and is used to drive the UAV to roll around its heading axis; The support fixture is installed on the tilting mechanism, which is used to position and install the drone, and rotates with the drone under the drive of the tilting mechanism; The load cells are installed at the bottom of the tilting mechanism. There are three load cells, one in front and two in the back, arranged in an isosceles triangle. The load cell at the vertex of the isosceles triangle is located directly below the UAV's heading axis. The load cells are used to collect weight information measured at the sensor's location under different attitudes of the UAV. The positioning detection sensor is mounted on the support fixture and is used to detect whether the drone is placed in the correct position on the support fixture; The weighing sensor and the positioning detection sensor are both connected to the production line control system to transmit their respective measurement data to the production line control system for processing; the power source of the tilting mechanism is a servo motor, which is electrically connected to and controlled by the production line control system.

4. The UAV automated transfer and centroid measurement collaborative operation system according to claim 3, characterized in that, The servo motor of the tilting mechanism is equipped with an encoder. The encoder is used to obtain the real-time roll angle of the drone and feed it back to the production line control system to form a closed-loop control for the adjustment of the drone's roll angle.

5. A method for automated transfer and center of gravity measurement of a UAV using the automated transfer and center of gravity measurement collaborative operation system of any one of claims 1-4, characterized in that, The method includes: Step 1. Transport the assembly stand carrying the drone to be tested to the transfer preparation position using an AGV transport vehicle; Step 2. The production line control system obtains the transfer control parameters and center of gravity measurement process parameters corresponding to the model of the UAV under test; according to the transfer control parameters, it controls each transfer actuator of the transfer unit to lift the UAV from the assembly table and move it along the ground rail to the set position on the bearing fixture of the center of gravity measurement unit. Step 3. The position information of the UAV positioning point is obtained by the positioning detection sensor of the centroid measurement unit and fed back to the production line control system to determine whether the UAV is in position. If it is in position, the UAV and the supporting tooling are fixedly connected. If it is not in position, the production line control system controls each transfer actuator to readjust the position of the UAV until it is in position, and then the UAV and the supporting tooling are fixedly connected. Step 4. The production line control system sends a center of gravity measurement command to the center of gravity measurement unit according to the measurement process parameters. The center of gravity measurement unit drives the UAV to rotate sequentially to the horizontal, forward roll and reverse roll attitudes. In each attitude, it collects data from each weighing sensor and feeds it back to the production line control system. The production line control system calculates the spatial coordinates of the center of gravity based on the torque balance equation and records the results. Step 5. After the centroid spatial coordinate measurement is completed, the fixed connection between the drone and the supporting tooling is removed. The production line control system controls each transfer actuator to transfer the drone back to the assembly stand at the initial position, completing one cycle of centroid measurement.

6. The method for coordinated automated transfer and centroid measurement of unmanned aerial vehicles according to claim 5, characterized in that, The transfer preparation position is located between the two ground rails and near the starting end of the ground rails; when the assembly stand carrying the drone arrives at the transfer preparation position, each transfer actuator is symmetrically located on both sides of the drone, and each transfer actuator is in the initial state, which is that the transfer actuator is located at the starting end of the ground rail, and the Y-axis is retracted and the Z-axis is in the lowest position.

7. The method for coordinated automated transfer and centroid measurement of unmanned aerial vehicles according to claim 5, characterized in that, The transfer control parameters include the X-axis stroke, Y-axis extension length, and Z-axis lifting height of each transfer actuator; the measurement process parameters of the center of gravity include the roll angle, stabilization time, and zero-point compensation coordinates during the measurement of the UAV's center of gravity.

8. The method for coordinated automated transfer and centroid measurement of unmanned aerial vehicles according to claim 5, characterized in that, If the production line control system fails to readjust the drone's position after a set number of attempts by each transfer actuator, the production line control system will trigger an emergency interruption and issue an alarm signal to await manual intervention.

9. The method for coordinated automated transfer and centroid measurement of unmanned aerial vehicles according to claim 5, characterized in that, When collecting data from each weighing sensor in each posture, the posture is held for a set stabilization time of 10-30 seconds before data collection is performed to eliminate the effects of inertia.

10. The method for coordinated automated transfer and centroid measurement of unmanned aerial vehicles according to claim 5, characterized in that, The methods for calculating the centroid spatial coordinates based on the torque balance equation in the production line control system include: The formula for calculating the mass of a drone and its centroid in the X direction is: (1) (2) (3) In the formula, Let P1 be the weight of the drone; denote the weight sensor located at the vertex of the isosceles triangle arrangement as P1, and the weight sensors located at the two endpoints of the base as P2 and P3. The reading of sensor P1 is given when the drone's roll angle is 0 degrees. The reading of sensor P2 is given when the drone's roll angle is 0 degrees. The reading of sensor P3 when the drone's roll angle is 0 degrees; The distance in the X direction from the center of mass of the UAV to sensor P1; The distance in the X direction from sensor P1 to sensors P2 and P3; The distance from the drone's center of mass to the drone's test baseline. This refers to the distance from the UAV test reference to the test instrument reference of the centroid measurement device (i.e., the zero-point compensation coordinate of the UAV nose end). The distance in the X direction from the test instrument reference to sensor P1 is the heading; The formulas for calculating the centroid of a UAV in the Y and Z directions are: (4) (5) In the formula, Let Y be the position of the centroid of the UAV in the Y direction. Let α be the position of the UAV's center of mass in the Z direction, and α be the UAV's roll angle. This is the reading of sensor P2 when the UAV rolls at an angle of +α. This is the reading of sensor P2 when the UAV rolls at an angle of -α. This is the reading of sensor P3 when the UAV rolls at an angle of +α. This is the reading of sensor P3 when the UAV rolls at an angle of -α. This is the distance from the centerline to sensor P2. This is the distance from the centerline to sensor P3.

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