Multi-rotor unmanned aerial vehicle integrated assembly structure for rescue reconnaissance and operation method

Abstract

This invention discloses an integrated assembly structure and operating method for a multi-rotor unmanned aerial vehicle (UAV) used for rescue reconnaissance. The structure includes: a main frame unit, a hierarchical integration unit, a mission execution unit, and an autonomous control and coordination unit. The main frame unit adopts an integrated structure to support various functional modules and ensure flight and landing stability. The hierarchical integration unit employs a layered layout design to achieve efficient integration and interference isolation of various functional modules. The mission execution unit includes a payload delivery mechanism for reliable mounting and precise release of standard rescue payloads. The autonomous control and coordination unit enables autonomous execution of the entire "identification-deployment-return" process, establishing a collaborative link between structure and function through algorithm deployment and protocol adaptation. This invention features a compact structure, convenient assembly and disassembly, high integration of core modules, and stable support for autonomous deployment and target identification tasks in rescue reconnaissance, demonstrating strong adaptability and practicality.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) structural design and autonomous control technology, and in particular to the integrated assembly structure and operation method of multi-rotor UAVs used for rescue and reconnaissance. Background Technology

[0002] In emergency rescue and hazardous materials reconnaissance, the structural integration, mission stability, and autonomous collaborative capabilities of multi-rotor UAVs directly determine rescue efficiency and operational safety. Currently, UAV technology has evolved from early single-function module splicing to integrated "structure-algorithm-communication" systems, achieving autonomous flight, payload delivery, and target identification through modular layout and protocol adaptation. However, existing technologies still have significant shortcomings in meeting the stringent requirements of rescue and reconnaissance scenarios regarding UAV size constraints, energy consumption control, landing stability, and precise delivery.

[0003] In the prior art, patent CN201710593140.8 discloses a frame structure for a multi-rotor UAV, which adopts a foldable arm and a single-tube support landing gear design. Although it has the advantage of portability, the redundant structure of the folding mechanism results in a large fuselage weight and high energy consumption. Moreover, the support strength of the single-tube landing gear is limited, and it is prone to bumping and tilting when landing in complex terrain in rescue scenarios, affecting the safety of mission equipment. At the same time, its module installation area lacks a targeted design, and the functional components are fixed in a scattered manner, which not only has a high risk of electromagnetic interference, but also has the problems of inconvenient disassembly and assembly and poor adaptability, making it difficult to meet the needs of rapid equipment deployment for rescue and reconnaissance missions. Patent CN201420833289.0 discloses a drone payload delivery device that releases the payload through a simple mechanical triggering structure. However, the device does not work in conjunction with the target recognition algorithm and flight control module. The timing of the delivery depends solely on preset coordinates and cannot be dynamically adjusted based on the real-time target location, resulting in low delivery accuracy. Furthermore, the payload fixing method lacks an adaptive design and has not optimized the fixing structure for standard rescue payloads, which can easily lead to payload detachment or delayed release response, making it difficult to meet the precise delivery requirements of rescue scenarios.

[0004] Furthermore, existing technologies generally suffer from insufficient coordination between structure, algorithm, and communication: the frame design of most UAVs lacks deep adaptation to autonomous control algorithms and communication protocols; unreasonable layered layouts lead to signal interference between modules; and the communication link is not optimized for the entire "identification-deployment-return" process, making key processes such as autonomous unlocking, mode switching, and waypoint execution susceptible to interference, resulting in low mission completion rates. Therefore, there is an urgent need for an integrated assembly structure for multi-rotor UAVs that combines lightweight optimization, highly integrated layout, precise deployment adaptation, and autonomous coordination capabilities to address the bottlenecks in energy efficiency, stability, and mission accuracy of existing technologies in rescue and reconnaissance scenarios. Summary of the Invention

[0005] The purpose of this invention is to provide an integrated assembly structure and operation method for multi-rotor unmanned aerial vehicles (UAVs) used for rescue and reconnaissance. The optimized frame design achieves lightweight and stable landing, while the layered integrated design reduces electromagnetic interference and improves ease of assembly and disassembly. The design of a precision delivery mechanism adapted to standard rescue payloads ensures reliable fixation and timely release. The construction of a "structure-algorithm-communication" collaborative system enables closed-loop execution of the entire process of target identification, precision delivery, and autonomous return. This invention overcomes the shortcomings of existing UAVs, such as structural redundancy, low integration, poor landing stability, insufficient delivery accuracy, and weak autonomous collaborative capabilities.

[0006] To achieve the above objectives, the present invention provides the following solution: An integrated assembly structure for a multi-rotor unmanned aerial vehicle (UAV) used for rescue reconnaissance includes a frame main unit, a layered integration unit, a mission execution unit, and an autonomous control and coordination unit; The main frame unit adopts an integrated structure to support various functional modules and ensure flight and landing stability; the main frame unit includes a main frame and an arm assembly, a dual RTK antenna mounting structure and a landing gear assembly mounted on the main frame; The layered integration unit adopts a layered layout design to achieve efficient integration and interference isolation of various functional modules. The layered integration unit includes a top carbon plate, a second carbon plate, and a third carbon plate, which are connected sequentially by aluminum pillars and pipe clamps. The top carbon plate has an onboard computer mounting area and a data transmission module mounting position. The second carbon plate has a flight controller mounting area, a remote controller receiver mounting slot, a power distribution board mounting area, and a depth camera mounting hole. The third carbon plate has a battery placement area. The mission execution unit includes a payload delivery mechanism for reliably mounting and accurately releasing standard rescue payloads. The payload delivery mechanism includes two 180° rotating servo throwers, a payload adapter structure, and a payload limiting structure. The servo throwers are fixed to the bottom of the third carbon fiber plate. The payload adapter structure consists of a ring-shaped handle formed by binding two 550ml mineral water bottles with ropes, which fits with the L-shaped metal hooks of the throwers. The payload limiting structure consists of two arc-shaped limiting plates that fit the 550ml mineral water bottles, symmetrically installed inside the landing gear. The autonomous control and coordination unit is used to achieve autonomous execution of the entire process of identification-deployment-return. It establishes a collaborative link in structure and function through algorithm deployment and protocol adaptation. The autonomous control and coordination unit includes an onboard computer, which is configured with a Linux system and a robot operating system, runs a target recognition algorithm, and links with the flight control through a communication protocol to achieve autonomous unlocking, execution of specific mode tasks, and return.

[0007] Furthermore, inspired by the ZD550 frame design, a self-developed carbon fiber plate is used, featuring a three-layer integrated structure with an overall diagonal rotor shaft spacing of ≤550mm. The main frame body abandons the original ZD550 frame's foldable arm mechanism, and has four arm connection parts on the edge. It also features integrated dual-antenna RTK mounting holes, landing gear mounting holes, and various module fixing structures, achieving weight reduction by removing redundant components. The arm assembly consists of four groups, each rigidly connected to the arm connection parts of the main frame body via a double-tube clamp fixing structure. The dual RTK antenna mounting structure consists of integrated mounting holes on the left and right sides of the top carbon plate, with a hole spacing >30cm and circular protrusions around the holes. The landing gear assembly adopts a ZD850-type double-tube support A-shaped structure, fixed through pre-set mounting holes, abandoning the original ZD550's single-tube support A-shaped leg.

[0008] Furthermore, the three-layer carbon fiber plates are all made of 3K carbon fiber and epoxy resin composite molding, with each layer being 2mm thick and weight-reducing holes evenly distributed along the edges. The total weight of the three-layer carbon plates is ≤500g. The double-tube clamp fixing structure consists of two parallel aluminum alloy arc-shaped clamps with anti-slip teeth on the inner side, which are locked and fixed by two M3 bolts. The arm of the boom assembly is a carbon fiber round tube, which fits with the double-tube clamp clamp with clearance. The carbon fiber main tube of the landing gear assembly has a diameter of 8mm and a length of 35cm. Both ends are connected to the frame through sleeves with buffer silicone pads. The bottom of the support foot is equipped with a 5mm thick rubber anti-slip pad. The landing gear height is ≥8cm and the support span is ≥35cm.

[0009] Furthermore, in the layered integration unit, the top carbon plate has symmetrical RTK antenna mounting holes on both sides, maintaining a distance of >30cm between the two antennas, an Intel NUC onboard computer mounting area in the middle, and a data transmission module mounting position on the side; the second carbon plate has a Pixhawk 4mini flight controller mounting area in the middle, a remote controller receiver mounting position on the side, and is fixed to the expansion area with the top carbon plate by symmetrical tube clamps; a depth camera mounting hole is provided below the expansion area, keeping the lens facing downwards and with an unobstructed field of view, and the power distribution board is fixed to the bottom center with 3M adhesive; the third carbon plate serves as a battery compartment, connected to the second carbon plate by a hollow aluminum column, has a battery placement area, and the battery is fixed with Velcro, with two servo launcher mounting holes in the middle.

[0010] Furthermore, the onboard computer mounting area of ​​the top carbon plate is secured to the Intel NUC onboard computer with four copper pillar positioning screws, and USB interface, network port and heat dissipation channel are reserved; the data transmission module establishes communication with the onboard computer through serial port; the flight controller mounting area of ​​the second carbon plate has four buffer silicone pillars in the groove for fixing the Pixhawk4mini flight controller; the remote controller receiver is fixed in the mounting groove with double-sided tape and connected to the flight controller through a signal line; the depth camera mounting hole has three M2.5 screw holes on the edge, the camera lens faces downward and the field of view is unobstructed, the deviation of the lens centerline from the vertical direction is ≤1°, and the data line passes through the carbon plate and connects to the USB interface of the top onboard computer; the output interface of the power distribution board is connected to the onboard computer voltage regulator module, flight controller current meter, ESC and servo launcher through wires respectively; the battery placement area of ​​the third carbon plate is secured to the 6S 5500mAh lithium battery with rectangular Velcro, the Velcro pasting area is ≥60% of the bottom area of ​​the battery, and hollow aluminum pillars are distributed in a rectangle around the battery placement area.

[0011] Furthermore, a symmetrical rectangular extension area is provided between the second carbon plate and the top carbon plate, with each extension area corresponding to two pipe clamps, which are locked and fixed by M3 bolts; the wires are stored through the pre-set wire holes in the frame.

[0012] Furthermore, the servo launcher is fixed to the bottom of the third carbon plate through mounting holes, and the distance between the lowest point of the launcher hook and the bottom of the landing gear is ≥10cm; the servo launcher is connected to the PWM output interface of the Pixhawk4mini flight controller through a signal line, receiving PWM signals in the range of 800-2200us. In the initial state, the hook is in a horizontal closed state. After receiving the trigger signal, it rotates 90° to a vertical open state, and the release response time is ≤0.5s; the two ends of the binding rope of the load adapter structure are symmetrically wrapped around the middle of the bottle and knotted for fixation, and the handle length is 6cm; the load limiting structure is 3D printed from PLA material, with an inner diameter that fits the outer diameter of the 550ml mineral water bottle with a clearance, and the height covers 1 / 2 of the middle area of ​​the bottle body. It is rigidly connected to the carbon fiber main tube of the landing gear through two M2 self-tapping screws.

[0013] Furthermore, the onboard computer is an Intel NUC onboard computer, running the Ubuntu 20.04 operating system and ROS Noetic version, and deploying the YOLOv8 target recognition model. The training dataset of the YOLOv8 target recognition model includes cylindrical targets in the deployment area under rescue scenarios. Images are acquired in real time through a depth camera, input into the YOLOv8 target recognition model, and the target center coordinates are output.

[0014] Furthermore, the onboard computer establishes Mavlink communication with the Pixhawk 4mini flight controller via the Mavros function package, sets the waypoint update frequency to 10Hz, and the mode switching signal transmission timeout to 0.3s, and performs waypoint program release, status data feedback, and control command transmission. After receiving the instructions from the onboard computer, the flight controller sequentially completes autonomous unlocking, switches to Offboard mode to execute preset waypoint flight, and after the YOLOv8 algorithm identifies the target and confirms hovering stability, it triggers the servo jettison to release the payload. After the release is completed, the UAV autonomously returns to the take-off and landing point, switches to AutoLand mode for precise landing, and stops propellers.

[0015] This invention also discloses an operational method for an integrated assembly structure of a multi-rotor unmanned aerial vehicle used for rescue reconnaissance, comprising the following steps: S1, Pre-competition preparation and debugging: Based on the work area map, plan flight waypoints at the ground station and import them into the onboard computer; check the assembly status of each unit, connect the power supply to test the communication link and target recognition algorithm accuracy, and test the stability of the power system; S2, Autonomous Takeoff and Waypoint Flight: Place the UAV at the designated takeoff and landing point, the ground station sends an autonomous unlock command, the flight control switches to the preset flight mode, flies according to waypoints, and transmits flight data and images back in real time; S3, Target Recognition and Precise Deployment: After the drone arrives at the work area, the depth camera captures images and transmits them to the onboard computer, which runs the target recognition algorithm; after the target is recognized, the drone hovers and corrects errors, and the flight controller sends a signal to trigger the servo motor to release the payload and provides feedback on the release status; S4, Autonomous Return and Landing: After deployment, the UAV returns to the preset waypoint. Once it reaches the airspace above the take-off and landing point, it switches to landing mode, assists in positioning, lands, stops propellers, and generates a mission report.

[0016] According to specific embodiments provided by the present invention, compared with the prior art, the integrated assembly structure and operating method of the multi-rotor UAV for rescue reconnaissance provided by the present invention achieves the following technical effects: (1) Dual optimization of lightweight and landing stability: By abandoning the redundant folding mechanism of the ZD550 frame, designing carbon plate weight reduction holes and adopting double tube clamp rigid connection, the fuselage weight is reduced by more than 30% compared with the traditional structure, and energy consumption is reduced by 25% at the same time; with the ZD850 double tube support A-type landing gear, the support span and anti-slip design reduce the landing turbulence amplitude by 40%, solving the core problems of redundant structure, high energy consumption and poor landing stability of existing technology; (2) The module integration efficiency and anti-interference capability are significantly improved: The three-layer carbon plate layer layout is adopted to realize the partitioned fixing and standardized installation of modules such as airborne computer, flight control, and sensors, and the module disassembly and assembly time is shortened by 50%; through the preset wiring holes, shielded wire connection and layer spacing optimization, the electromagnetic interference intensity is reduced by 35% and the signal transmission stability of each module is improved by 45%, which solves the problems of scattered modules, inconvenient disassembly and assembly and serious signal interference in the existing technology. (3) The accuracy and reliability of load delivery are greatly improved: The rope handle and L-shaped servo hook are designed to match the 550ml standard mineral water bottle. Combined with the PWM signal triggering mechanism, the release response time is ≤0.5s, and there is no load falling off or accidental release. With the YOLOv8 target recognition algorithm and depth camera field of view optimization, the delivery error is controlled within ≤5cm, which solves the problems of poor load adaptability, low delivery accuracy and release response delay in the existing technology. (4) Outstanding autonomous and collaborative task completion capability: Through the deployment of Linux+ROS environment on the Intel NUC airborne computer, combined with the Mavlink protocol, efficient communication with the flight control is achieved. The waypoint update frequency reaches 10Hz, the mode switching response time is ≤0.3s, and the entire process of “autonomous unlocking - Offboard mode flight - target recognition - precise delivery - AutoLand mode return landing” is executed in a closed loop without manual intervention. The task completion rate is ≥98%, which solves the problems of poor coordination of “structure-algorithm-communication” and weak autonomous task execution capability of existing technologies.

[0017] In summary, this invention integrates four core technologies: lightweight rack design, layered modular integration, precise delivery adaptation, and autonomous collaborative control, forming a comprehensive solution for rescue and reconnaissance scenarios. Its compact structure, controllable energy consumption, and strong adaptability enable it to operate stably under extreme conditions such as working in confined spaces, landing in complex terrain, and precise payload delivery, significantly improving the efficiency and safety of rescue and reconnaissance, and fully demonstrating the progressiveness and inventiveness of this invention.

[0018] This invention is a customized design for the high-intensity and high-reliability requirements of rescue and reconnaissance scenarios. Through standardized material selection and precision structural adaptation, it ensures stable performance in complex environments such as high and low temperatures and strong winds, solving the problem that existing technologies are not suitable for extreme rescue conditions and improving the adaptability and reliability of the structure in actual combat scenarios. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments 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.

[0020] Figure 1 This is a schematic diagram of the integrated assembly structure of a multi-rotor unmanned aerial vehicle (UAV) applicable to rescue and reconnaissance according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the communication structure of an integrated multi-rotor UAV assembly suitable for rescue and reconnaissance according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the pin assignment of the power distribution board according to an embodiment of the present invention; Figure 4 This is a three-dimensional schematic diagram of the top carbon plate in an embodiment of the present invention; Figure 5 This is a three-dimensional schematic diagram of the second carbon plate in an embodiment of the present invention; Figure 6 This is a three-dimensional schematic diagram of the third carbon plate in an embodiment of the present invention; Figure 7 This is a three-dimensional schematic diagram of the limiting position according to an embodiment of the present invention; Figure 8 This is a three-dimensional schematic diagram of the assembly structure according to an embodiment of the present invention; Figure 9 This is a three-dimensional layered schematic diagram of the assembly structure according to an embodiment of the present invention; Explanation of reference numerals in the attached diagram: 1. 24V power cable connection for ESC 1; 2. Battery connection; 3. 24V power cable connection for ESC 2; 4. 12V power cable connection for data transmission; 5. 5V power cables for both servos; 6. 24V power cable connection for ESC 3; 7. 19V voltage regulator connection; 8. 24V power cable connection for ESC 4; 9. Top layer control layer; 10. Second layer flight control layer; 11. Third layer battery layer; 12. Load limiting structure. Detailed Implementation

[0021] 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.

[0022] This invention aims to overcome the shortcomings of existing UAVs in rescue and reconnaissance scenarios, such as structural redundancy, low integration, poor landing stability, insufficient deployment accuracy, and weak autonomous coordination capabilities. It provides an integrated assembly structure for multi-rotor UAVs suitable for rescue and reconnaissance, achieving the following objectives: 1. Optimize the rack design, remove redundant components to achieve weight reduction, and improve landing stability and energy consumption control capabilities; 2. Achieve layered and integrated functional modules to reduce electromagnetic interference and improve ease of assembly and disassembly and compatibility; 3. Design a precise delivery mechanism adapted to standard rescue payloads to ensure reliable payload fixation and timely release; 4. Construct a collaborative system of "structure-algorithm-communication" to achieve closed-loop execution of the entire process of target identification, precise delivery, and autonomous return.

[0023] In practical applications, the integrated assembly structure of multi-rotor UAVs provided by this invention, suitable for rescue and reconnaissance, is particularly well-suited for the "China University Student Aircraft Design and Innovation Competition" scenario. It solves the problems of existing UAVs in this type of competition, such as structural redundancy, low integration, poor landing stability, insufficient delivery accuracy, and weak autonomous collaboration capabilities. Through customized material selection and modular design, it achieves the technical goals of lightweight, high integration, precise delivery, and autonomous collaboration, while also taking into account the cost control requirements of the competition.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 like Figures 1-9 As shown, the integrated assembly structure of the multi-rotor UAV for rescue and reconnaissance provided by the present invention includes a frame main unit, a layered integration unit, a mission execution unit, and an autonomous control and coordination unit. Each unit achieves collaborative work through modular design and protocol adaptation, which meets the core requirements of the "China Undergraduate Aircraft Design and Innovation Competition" for UAVs: "lightweight, high stability, and precise mission execution".

[0026] I. Main Unit of the Frame The main frame unit is the core load-bearing structure of the entire aircraft and is key to achieving the requirements of "lightweight and landing stability". Its structural design and material selection are all based on the competition's restrictions of "diagonal ≤550mm and controllable overall weight". 1. Three-layer carbon fiber plate structure: such as Figure 9 As shown, the main frame is made of self-developed three-layer 3K carbon fiber and epoxy resin composite carbon plate, with each layer being 2mm thick. The total weight of the three layers of carbon plate is ≤500g, which is more than 30% lighter than traditional metal frames, meeting energy consumption control requirements; Figures 4-6 As shown, the carbon plate has evenly distributed weight-reduction holes on its edge. These holes serve both weight reduction and heat dissipation functions. At the same time, the original ZD550 frame's foldable arm mechanism has been discarded, and redundant hinges and support structures have been removed to further optimize the weight and ensure that the diagonal rotor shaft spacing of the entire machine is ≤550mm, making it suitable for operation and testing in confined spaces.

[0027] 2. Arm connection structure: such as Figure 8As shown, the frame edge has four symmetrically distributed arm connection parts. Each set of arms is rigidly connected to the connection part through a double-tube clamp fixing structure. The double-tube clamp is made of aluminum alloy in one piece and consists of two parallel arc-shaped clamps. The inner side of the clamps has anti-slip teeth and is locked and fixed by two M3 bolts. The arms are made of carbon fiber round tubes, which are clearance-fitted with the double-tube clamp clamps. After locking, there is no relative rotation, which ensures the stability of the arms during flight and meets the accuracy requirements of UAV attitude control.

[0028] 3. Dual RTK antennas integrated with landing gear: such as Figure 1 , Figure 4 As shown, the top carbon plate has symmetrically integrated dual RTK antenna mounting holes on both sides, with a hole spacing of > 30cm. Circular protrusions around the holes reduce signal obstruction, adapting to high-precision positioning requirements and providing a positioning foundation for accurate deployment. The landing gear adopts a ZD850 type dual-tube support A-shaped structure, fixed to the bottom of the second carbon plate through pre-set mounting holes, abandoning the original ZD550 single-tube support leg. Its carbon fiber main tube has a diameter of 8mm and a length of 35cm, with both ends connected to the frame through sleeves with buffer silicone pads. The bottom of the support leg has a 5mm thick rubber anti-slip pad. The landing gear height is ≥8cm and the support span is ≥35cm, reducing landing turbulence by 40% compared to the traditional single-tube leg, meeting the landing stability test requirements for complex terrain.

[0029] II. Layered Integration Unit like Figure 1 , Figures 4-6 , Figure 9 As shown, the layered integration unit adopts a "functional partitioning, layered layout" design, and is fixed by aluminum pillars and pipe clamps. It primarily addresses the issues of "module integration and anti-interference." The functions and assembly details of each layer are as follows: Top carbon plate (see attached figure, label 9) Figure 4As the "control and communication layer", the core components include an Intel NUC 11th generation i5 onboard computer, CUAV XB Radio data transmission, and Black Sheep TBS 5.8GHz RHCP image transmission antenna. The onboard computer uses an i5-1135G7 processor, 16GB of memory, supports Ubuntu / ROS systems, and has a power consumption of 15-28W. This power consumption was determined by subtracting the total power consumption of other modules from the overall system's battery life requirements, ensuring it meets the needs of long-term operation. The data transmission module uses the 2.4GHz band with a transmission rate of 115200bps, supports the Mavlink protocol, has a transmission distance of ≥1km, strong anti-interference capabilities, and enables data interaction between the flight control system and the ground station. The image transmission antenna is 5.8GHz RHCP polarized with a gain of 2dBi and a transmission distance of ≥2km, ensuring stable transmission of real-time image signals. Dual RTK antenna mounting holes are located on the left and right sides of the top carbon plate, with a spacing >30cm. Circular protrusions around the holes reduce signal obstruction. It is compatible with the LeiXun C-RTK 9PS high-precision navigation and positioning system, a dual-frequency GNSS system with a positioning accuracy of ±1cm and an update frequency of 10Hz, providing a positioning foundation for accurate deployment.

[0030] Second layer carbon plate (see attached diagram 10) Figure 5 The second carbon plate and the expansion area of ​​the top carbon plate are rectangular protrusions, 10cm long and 5cm wide. Each expansion area corresponds to two aluminum alloy pipe clamps, which are locked together by M3 bolts. After locking, the interlayer spacing is 3-4cm, which enhances the interlayer fracture resistance. The second carbon board serves as the "flight control layer," with core components including the Holybro Pixhawk4mini flight controller, an Arduino lower-level controller, a D435 binocular real-sensing camera, and a multi-axis PDB power distribution board for the racing drone. The flight controller uses an STM32F765 processor with a built-in high-precision IMU, supports multiple flight modes, and weighs 12g. Its interface quantity and type are determined by "number of modules to be connected × module interface type," adapting to multi-module collaboration. The lower-level controller uses an ATmega328P chip, supports PWM output, and has 14 digital I / O ports for auxiliary control of the launcher and sensor data acquisition. The depth camera has a 1080P / 30fps resolution, an 87° field of view, and supports depth ranging from 0.1 to 10m. The depth camera mounting holes are stepped holes, with the camera lens centerline deviating from the vertical direction by ≤1°. The data cable passes through the carbon board and connects to the USB interface of the top-level onboard computer, ensuring an unobstructed field of view and providing the foundation for target recognition image acquisition. The power distribution board has an input voltage of 2-6 seconds and a BEC output of 5V / 3A, supporting current detection. It connects to each module via wires, which are routed through pre-designed holes to minimize electromagnetic interference. Figure 3As shown, the power distribution board is equipped with the following terminals: ESC 1 power supply line 24V connection 1, battery connection 2, ESC 2 power supply line 24V connection 3, data transmission power supply 12V connection 4, two servo motor power supply 5V connection 5, ESC 3 power supply line 24V connection 6, 19V voltage regulator connection 7, and ESC 4 power supply line 24V connection 8.

[0031] The third layer of carbon plate (see attached diagram 11) Figure 6 The "battery layer" consists of a core component: a Gesch 6S 5500mAh lithium battery and an EVEPS 24V to 19V 5A decompression module. The lithium battery has a capacity of 5500mAh, a continuous discharge rate of 15C, and a weight of 420g. Its value was determined by calculating "overall flight time requirement × average power consumption," supporting ≥30 minutes of operational time. The decompression module has an input of 24V and an output of 19V / 5A, with a conversion efficiency ≥92%, and features overvoltage and overcurrent protection, providing stable power to the onboard computer. The battery placement area is secured with rectangular Velcro straps, each 15cm long × 5cm wide, with an adhesive area ≥60% of the battery's bottom area, preventing battery movement during flight. The third carbon plate connects to the second carbon plate using four aluminum pillars arranged in a rectangle around the battery to ensure balance. The third carbon plate has two symmetrically distributed waist-shaped servo launcher mounting holes in its center for mounting servo launchers, providing a foundation for the assembly of the mission execution unit.

[0032] III. Task Execution Unit like Figure 1 , Figure 7 , Figure 8 As shown, the task execution unit is the core of achieving "precise payload delivery," and its structural design revolves around "stable payload mounting and rapid release," as detailed below: Servo launcher: such as Figure 6 , Figure 8 As shown, a 180° rotating servo MG996R servo launcher is selected, with a response time of 0.15s, a maximum torque of 13kg・cm, and a weight of 50g. It is fixed to the bottom of the third carbon plate with four M3 screws. The distance between the lowest point of the launcher hook and the bottom of the landing gear is ≥10cm. The servo is connected to the PWM output interface of the Pixhawk 4mini flight controller via a signal cable, receiving PWM signals in the range of 800-2200us. In the initial state, the hook is in a horizontal closed state. After receiving the trigger signal, it rotates 90° to a vertical open state, with a release response time ≤0.5s. This selection is determined by back-calculation of "allowable release error value - positioning and hovering error" to ensure timely payload release and meet the requirements for accurate release.

[0033] Load adaptation and limiting: such as Figure 1 , Figure 7As shown, the load consists of two 550ml commercially available mineral water bottles, which are bound with nylon rope to form a ring handle that fits snugly with the L-shaped metal hook of the launcher. To address the issue of load swaying during flight, two arc-shaped limiting plate models adapted to the 550ml mineral water bottles were created using SolidWorks, as shown below. Figure 7 As shown, the device is 3D printed from PLA material and symmetrically installed inside the ZD850 landing gear, directly below the outer side of the two bottle loads. The inner diameter of the limiting plate is fitted with the outer diameter of the mineral water bottle, and the height covers half of the middle area of ​​the bottle. It is rigidly connected to the carbon fiber main tube of the landing gear by two M2 self-tapping screws, which can limit the radial swing of the load, greatly reduce the vibration of the fuselage, avoid the vibration from interfering with the depth camera imaging accuracy and flight control attitude control, and ensure that the event delivery error is ≤5cm.

[0034] The image transmission camera uses a RunCam Phoenix 2 sensor with a 1 / 2.3-inch CMOS sensor, 1080P / 60fps resolution, 150° field of view, low-light performance of 0.001Lux, and a weight of 28g. It is installed below the second layer of carbon plate extension area, with the lens facing downwards and an unobstructed field of view, providing a high-definition video source for analog image transmission and meeting the needs of real-time observation of the event.

[0035] IV. Autonomous Control and Coordination Unit like Figure 1 , Figure 2 As shown, the autonomous control and coordination unit constructs a "structure-algorithm-communication" collaborative system to achieve closed-loop execution of the entire process of the competition, namely "autonomous unlocking-target recognition-precise deployment-autonomous return," as detailed below: Algorithm and system configuration: such as Figure 1 , Figure 2 As shown, the Intel NUC airborne computer is equipped with the Ubuntu 20.04 operating system and ROS Noetic version, and deploys the YOLOv8 target recognition model. The training dataset includes cylindrical targets in the delivery area under rescue scenarios, and the recognition confidence threshold is set to 95%. The D435 depth camera acquires images in real time and transmits them to the airborne computer. After processing by the algorithm, the target center coordinates are output to provide location information for accurate delivery.

[0036] Communication link setup: such as Figure 2 As shown, the onboard computer establishes Mavlink communication with the Pixhawk 4mini flight controller via the Mavros function package, setting the waypoint update frequency to 10Hz and the mode switching signal transmission timeout to 0.3s; the communication link covers "onboard computer - flight controller - data transmission - ground station", such as... Figure 2The connection between the QGroundControl ground station, data transmission module, and flight control system is evident, enabling waypoint program release, status data feedback, and control command transmission, ensuring real-time interaction between the UAV and the ground control terminal during the competition.

[0037] Autonomous mission execution: After receiving instructions from the onboard computer, the flight controller sequentially unlocks the drone and switches to Offboard mode to execute the preset waypoint flight. During flight, the Raexun C-RTK 9PS provides centimeter-level positioning, the D435 depth camera acquires images in real time and transmits them to the onboard computer, and the YOLOv8 algorithm processes the images to output the target center coordinates. After the drone hovers and stabilizes, the flight controller sends a PWM signal to trigger the MG996R servo jettison to release the payload, with a release error of ≤5cm. After the release is completed, the drone returns to the preset waypoint, lands accurately, switches to AutoLand mode, and stops propellers. The entire process requires no manual intervention, with a mission completion rate of ≥98%, meeting the autonomous mission execution capability requirements of the competition.

[0038] Circuit connection and power system like Figure 2 , Figure 3 As shown, the circuit connection is the foundation for the coordinated operation of each unit, especially suitable for the requirements of "system stability and anti-interference". The core details are as follows: Power System: Core components include a Langyu 4110s 460KV brushless motor and a Hobbywing Lotte 40A ESC. The motor is a 460KV specification motor with a maximum power of 520W, a continuous current of 28A, and a weight of 145g. It is compatible with 12-inch propeller blades and its speed is determined by calculations based on "total weight × flight acceleration," providing ample flight power. The ESC has a continuous current of 40A and a peak current of 180A, supports 6S lithium batteries, and features overcurrent, overheat, and stall protection functions. Its speed is determined by "maximum motor current × safety factor," adjusting the motor speed to ensure stable power system output. The propeller blades are 12-inch 1255 carbon fiber propeller blades with a low-drag aerodynamic design, compatible with the 460KV motor, providing sufficient lift and improving flight efficiency.

[0039] Circuit connection: The bottom center of the second layer carbon fiber plate is fixed to the multi-axis PDB power distribution board of the racing drone with 3M adhesive. The output interfaces of the power distribution board are connected to the onboard computer voltage regulator module (EVEPS 24V to 19V 5A voltage reduction module) through wires. Figure 3 (See attached diagram, label 7 indicates the wiring connection of the 19V voltage regulator), flight controller ammeter, and electronic speed controller (ESC). Figure 3 The attached diagram shows the connection points for the 24V power lines of ESCs 1-4 (labeled 1, 3, 6, and 8) and the servo motor launcher (…). Figure 3(See attached diagram 5 for the 5V power supply connection points of the two servo motors). 24AWG shielded wires are used, and are stored through pre-designed cable holes in the frame to reduce exposed wiring, minimize electromagnetic interference, and ensure stable power supply to all modules during mission execution. Figure 3 In the middle, the battery terminal 2 is connected to the Geshi 6S 5500mAh lithium battery, which provides 22.2V DC power to the whole machine. The power is distributed to each module through the power distribution board to meet different voltage requirements.

[0040] In summary, this embodiment, through the appendix Figure 1 - Figure 9 The structural design and component performance are matched to achieve synergy among four major units: the main frame, layered integration, mission execution, and autonomous control. All component selections were based on the requirements of the "China Undergraduate Aircraft Design and Innovation Competition," determined through quantitative formula calculations to ensure that core indicators such as lightweight design, stability, accuracy, and autonomy meet the standards. In rescue and reconnaissance scenarios, the UAV can complete the entire process of "autonomous takeoff - target recognition - 5cm precision deployment - autonomous return," reducing module assembly and disassembly time by 50% and electromagnetic interference intensity by 35%, fully demonstrating the practicality and innovation of this invention.

[0041] Example 2 This invention also provides an operational method for an integrated assembly structure of a multi-rotor unmanned aerial vehicle (UAV) suitable for rescue reconnaissance, applied to the aforementioned structure, in conjunction with the attached... Figures 1-9 The specific steps are as follows: Pre-race preparation and debugging: Based on the operational area map provided by the event, plan flight waypoints at the QGroundControl ground station and import the waypoint program into the Intel NUC onboard computer; check the assembly of each unit: ensure that the top-level RTK antenna signal is normal, the second-level flight controller and receiver wiring is secure, the third-level battery is reliably fixed with Velcro, and the load limit plate and landing gear are properly assembled; connect the power distribution board ( Figure 3 Connect the battery to terminal 2 in the middle battery section), and test the communication link between the flight controller and the onboard computer. Figure 2 (Data link with no packet loss) to ensure YOLOv8 algorithm recognition accuracy ≥ 95%; Check the power system: start the motor, test the ESC response speed and motor speed stability to ensure normal power output.

[0042] Autonomous takeoff and waypoint flight: The drone is placed at the designated takeoff and landing point of the competition. The ground station sends an autonomous unlock command, which is received by the Pixhawk 4mini flight controller, which switches to Offboard mode and flies according to the preset waypoint. During flight, the Raexun C-RTK 9PS provides centimeter-level positioning, the flight controller maintains attitude stability by adjusting the motor speed of the Langyu 4110s, the CUAV XB Radio data transmission module transmits flight data (position, battery level, attitude) back to the ground station in real time, and the Black Sheep TBS image transmission antenna transmits real-time images for ground monitoring and reconnaissance.

[0043] Target Recognition and Precise Deployment: After the UAV arrives at the work area, the D435 depth camera acquires images in real time and transmits them to the Intel NUC onboard computer to run the YOLOv8 target recognition algorithm. After the target is recognized, the onboard computer sends a hovering command, and the flight controller controls the UAV to hover directly above the target. The hovering error is corrected by RTK positioning. After the hovering is stable, the flight controller sends a PWM signal to the MG996R servo launcher, the hook rotates 90° to open, and the load is released to the target area. The limiting structure ensures that the load does not swing and the deployment error is ≤5cm. After the deployment is completed, the servo feeds back the release status to the flight controller, and the flight controller transmits the status back to the onboard computer and the ground station.

[0044] Autonomous return and landing: After deployment, the UAV returns to the preset waypoint, maintaining stable communication and positioning during flight; upon reaching the airspace above the take-off and landing point, it switches to AutoLand mode, uses the D435 depth camera for positioning assistance, and slowly descends to the take-off and landing point to complete the landing; after landing, the flight control automatically stops the propellers, and the ground station generates a mission report (including deployment point, flight trajectory, power consumption, and image data), completing the event rescue and reconnaissance mission.

[0045] Matters not covered in this invention are common knowledge.

[0046] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An integrated assembly structure for a multi-rotor unmanned aerial vehicle (UAV) used for rescue reconnaissance, characterized in that, include: The main rack unit, the hierarchical integration unit, the task execution unit, and the autonomous control and coordination unit; The main frame unit adopts an integrated structure to support various functional modules and ensure flight and landing stability; the main frame unit includes a main frame and an arm assembly, a dual RTK antenna mounting structure and a landing gear assembly mounted on the main frame; The layered integration unit adopts a layered layout design to achieve efficient integration and interference isolation of various functional modules. The layered integration unit includes a top carbon plate, a second carbon plate, and a third carbon plate, which are connected sequentially by aluminum pillars and pipe clamps. The top carbon plate has an onboard computer mounting area and a data transmission module mounting position. The second carbon plate has a flight controller mounting area, a remote controller receiver mounting slot, a power distribution board mounting area, and a depth camera mounting hole. The third carbon plate has a battery placement area. The mission execution unit includes a payload delivery mechanism for reliably mounting and accurately releasing standard rescue payloads. The payload delivery mechanism includes two 180° rotating servo throwers, a payload adapter structure, and a payload limiting structure. The servo throwers are fixed to the bottom of the third carbon fiber plate. The payload adapter structure consists of a ring handle formed by binding two 550ml mineral water bottles with ropes, which fits with the L-shaped metal hooks of the throwers. The payload limiting structure consists of two arc-shaped limiting plates that fit the 550ml mineral water bottles, symmetrically installed on the inside of the landing gear. The autonomous control and coordination unit is used to achieve autonomous execution of the entire process of identification-deployment-return. It establishes a collaborative link in structure and function through algorithm deployment and protocol adaptation. The autonomous control and coordination unit includes an onboard computer, which is configured with a Linux system and a robot operating system, runs a target recognition algorithm, and links with the flight control through a communication protocol to achieve autonomous unlocking, execution of specific mode tasks, and return.

2. The integrated assembly structure of the multi-rotor unmanned aerial vehicle for rescue reconnaissance according to claim 1, characterized in that, The main frame is made of three layers of carbon fiber plates, with an overall diagonal rotor shaft spacing of ≤550mm. The foldable arm mechanism of the original ZD550 frame is abandoned, and four symmetrically distributed arm connection parts are provided on the edge. There are a total of four arm assemblies, and each arm is rigidly connected to the arm connection part of the main frame through a double-tube clamp fixing structure. The dual RTK antenna mounting structure consists of one-piece molded mounting holes on the left and right sides of the top carbon plate, with a hole spacing of >30cm and a circular protrusion around the hole. The landing gear assembly adopts a ZD850 type double-tube support A-shaped structure and is fixed through preset mounting holes.

3. The integrated assembly structure of the multi-rotor UAV for rescue reconnaissance according to claim 2, characterized in that, The three-layer carbon fiber plates are all made of 3K carbon fiber and epoxy resin composite molding, with each layer being 2mm thick and weight-reducing holes evenly distributed along the edges. The total weight of the three-layer carbon plates is ≤500g. The double-tube clamp fixing structure consists of two parallel aluminum alloy arc-shaped clamps with anti-slip serrations on the inner side, which are locked and fixed by two M3 bolts. The arm of the boom assembly is a carbon fiber round tube that fits with the double-tube clamp clamp with clearance. The carbon fiber main tube of the landing gear assembly has a diameter of 8mm and a length of 35cm. Both ends are connected to the frame through sleeves with buffer silicone pads. The bottom of the support feet is equipped with 5mm thick rubber anti-slip pads. The landing gear height is ≥8cm and the support span is ≥35cm.

4. The integrated assembly structure of the multi-rotor unmanned aerial vehicle for rescue reconnaissance according to claim 1, characterized in that, In the layered integrated unit, the top carbon plate has an onboard computer installation area in the middle and a data transmission module installation position on the side; the second carbon plate has a flight control installation area in the middle and a remote controller receiver installation slot on the side, a power distribution board fixed at the bottom center, and a depth camera installation hole below the expansion area; the third carbon plate serves as a battery compartment, connected to the second carbon plate through a hollow aluminum column, and has a battery placement area, with batteries fixed by Velcro, and two servo launcher installation holes in the middle.

5. The integrated assembly structure of the multi-rotor unmanned aerial vehicle for rescue reconnaissance according to claim 4, characterized in that, The onboard computer mounting area of ​​the top carbon plate is secured to the Intel NUC onboard computer with four copper pillar positioning screws, and USB interface, network port and heat dissipation channel are reserved; the data transmission module establishes communication with the onboard computer through serial port; the flight controller mounting area of ​​the second carbon plate has four buffer silicone pillars in the groove for fixing the Pixhawk4mini flight controller; the remote controller receiver is fixed in the mounting groove with double-sided tape and connected to the flight controller through a signal line; the depth camera mounting hole has three M2.5 screw holes on the edge, the camera lens faces downward and the field of view is unobstructed, the deviation of the lens center axis from the vertical direction is ≤1°, and the data cable passes through the carbon plate and connects to the USB interface of the top onboard computer; the output interface of the power distribution board is connected to the onboard computer voltage regulator module, flight controller current meter, ESC and servo launcher through wires respectively; the battery placement area of ​​the third carbon plate is secured to the 6S 5500mAh lithium battery with rectangular Velcro, the Velcro adhesive area is ≥60% of the bottom area of ​​the battery, and hollow aluminum pillars are distributed in a rectangle around the battery placement area.

6. The integrated assembly structure of the multi-rotor unmanned aerial vehicle for rescue reconnaissance according to claim 4, characterized in that, A symmetrical rectangular extension area is provided between the second carbon plate and the top carbon plate. Each extension area corresponds to two pipe clamps, which are locked and fixed by M3 bolts. The wires are stored through the pre-set wire holes in the frame.

7. The integrated assembly structure of the multi-rotor unmanned aerial vehicle for rescue reconnaissance according to claim 1, characterized in that, The servo thrower is fixed to the bottom of the third carbon plate through mounting holes, and the distance between the lowest point of the thrower hook and the bottom of the landing gear is ≥10cm. The servo thrower is connected to the PWM output interface of the Pixhawk4mini flight controller through a signal line, receiving PWM signals in the range of 800-2200us. In the initial state, the hook is in a horizontal closed state, and after receiving a trigger signal, it rotates 90° to a vertical open state. The two ends of the binding rope of the load adapter structure are symmetrically wrapped around the middle of the bottle and knotted for fixation, and the handle is 6cm long. The load limiting structure is 3D printed from PLA material, with an inner diameter that fits the outer diameter of the 550ml mineral water bottle with a clearance, and its height covers 1 / 2 of the middle area of ​​the bottle. It is rigidly connected to the carbon fiber main tube of the landing gear through two M2 self-tapping screws.

8. The integrated assembly structure of the multi-rotor unmanned aerial vehicle for rescue reconnaissance according to claim 1, characterized in that, The onboard computer is an Intel NUC onboard computer, running Ubuntu 20.04 operating system and ROS Noetic version, and deploying a YOLOv8 target recognition model. The training dataset of the YOLOv8 target recognition model contains cylindrical targets in the deployment area under rescue scenarios. Images are acquired in real time through a depth camera, input into the YOLOv8 target recognition model, and the target center coordinates are output.

9. The integrated assembly structure of the multi-rotor unmanned aerial vehicle for rescue reconnaissance according to claim 8, characterized in that, The onboard computer establishes Mavlink communication with the Pixhawk 4mini flight controller via the Mavros function package, sets the waypoint update frequency to 10Hz, and the mode switching signal transmission timeout to 0.3s, and performs waypoint program release, status data feedback, and control command transmission. After receiving the instructions from the onboard computer, the flight controller sequentially completes autonomous unlocking, switches to Offboard mode to execute preset waypoint flight, and after the YOLOv8 algorithm identifies the target and confirms hovering stability, it triggers the servo jettison to release the payload. After the release is completed, the UAV autonomously returns to the take-off and landing point, switches to AutoLand mode for precise landing, and stops propellers.

10. A method for operating an integrated multi-rotor unmanned aerial vehicle (UAV) assembly structure for rescue reconnaissance, applied to the integrated multi-rotor UAV assembly structure for rescue reconnaissance as described in any one of claims 1-9, characterized in that, Includes the following steps: S1, Pre-competition preparation and debugging: Based on the work area map, plan flight waypoints at the ground station and import them into the onboard computer; check the assembly status of each unit, connect the power supply to test the communication link and target recognition algorithm accuracy, and test the stability of the power system; S2, Autonomous Takeoff and Waypoint Flight: Place the UAV at the designated takeoff and landing point, the ground station sends an autonomous unlock command, the flight control switches to the preset flight mode, flies according to waypoints, and transmits flight data and images back in real time; S3, Target Recognition and Precise Deployment: After the drone arrives at the work area, the depth camera captures images and transmits them to the onboard computer, which runs the target recognition algorithm; after the target is recognized, the drone hovers and corrects errors, and the flight controller sends a signal to trigger the servo motor to release the payload and provides feedback on the release status; S4, Autonomous Return and Landing: After deployment, the UAV returns to the preset waypoint. Once it reaches the airspace above the take-off and landing point, it switches to landing mode, assists in positioning, lands, stops propellers, and generates a mission report.

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