Double-unmanned-aerial-vehicle synchronous control method and system for line crimping fitting detection

Abstract

The invention belongs to the technical field of electric power transmission line fitting crimping quality detection. The invention provides a double-unmanned-aerial-vehicle synchronous control method and system for line crimping fitting detection. Two unmanned aerial vehicles respectively receive a detection initial path and a time synchronization parameter of a ground control terminal; the two unmanned aerial vehicles fly according to respective detection initial paths and keep time synchronization according to the time synchronization parameters; after reaching a detection area, the first unmanned aerial vehicle is adjusted to a detection position, the second unmanned aerial vehicle is adjusted to a ray emission position, and the first unmanned aerial vehicle and the second unmanned aerial vehicle perform target point joint positioning through time difference positioning and direction finding positioning; the transmitter transmits rays to the flat panel detector, the flat panel detector receives a ray signal and converts the ray signal into an electric signal, and the electric signal is relayed by the second unmanned aerial vehicle and then transmitted back to the ground control terminal for line crimping fitting detection; according to the invention, automatic dynamic positioning of the target point and synchronous control of the double unmanned aerial vehicles are realized, and the detection efficiency, safety and reliability are improved.

Description

Technical Field

[0001] This invention relates to the field of power transmission line fitting crimping quality inspection technology, specifically to a dual-UAV synchronous control method and system for line crimping fitting inspection. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In recent years, numerous line operation accidents, including power outages, power cuts, and tower collapses, have occurred due to problems with the crimping quality of tension clamps. Post-accident analysis revealed that most accidents were caused by crimping quality issues, such as conductors and ground wires not being properly threaded into the crimping pipe or crimping positions not conforming to relevant regulations. Given the importance of inspecting and evaluating the crimping quality of tension clamps in transmission lines, unmanned aerial vehicle (UAV) digital radiographic non-destructive testing (UAV) technology is now widely used. This technology eliminates the need for manual tower climbing, reducing the safety risks of manual operations, providing real-time digital radiographic images on-site, allowing for real-time assessment of the internal crimping quality of the clamps, and enabling live-line testing. Its high efficiency has led to its increasingly widespread application.

[0004] However, existing drones have the following technical problems: In typical dual-drone digital X-ray nondestructive testing, drone A hoists the digital X-ray flat panel detector and hangs the wires, while drone B carries the X-ray machine and dynamically aligns it with the flat panel detector to excite the X-ray and test the crimping quality of the fittings. During this process, drone B's onboard camera visually locates and aligns with the flat panel detector, lacking an effective automatic dynamic positioning and synchronization control method, resulting in low testing efficiency. Dual drones also lack autonomous obstacle avoidance and path planning, which may lead to drone collisions and crashes due to visual errors, damaging power transmission line conductors and affecting the safety and reliability of drone digital X-ray nondestructive testing. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a dual-UAV synchronous control method and system for inspecting line crimping fittings. This method enables automatic dynamic positioning of target points and synchronous control of the two UAVs during the digital X-ray inspection of power transmission line fittings using dual UAVs, thereby improving inspection efficiency and safety reliability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a dual-UAV synchronous control method for detecting line crimping fittings.

[0007] A dual-UAV synchronous control method for inspecting line crimping fittings, comprising a first UAV and a second UAV communicating with a ground control terminal respectively. The first UAV is used to hoist a flat panel detector, and the second UAV is used to hoist a transmitter that works in conjunction with the flat panel detector. The method includes the following processes: The first and second UAVs respectively receive the initial path detection and time synchronization parameters from the ground control terminal; The first and second UAVs flew along their respective initial detection paths and maintained time synchronization according to the time synchronization parameters. Upon reaching the detection area, the first UAV adjusts to the detection position, and the second UAV adjusts to the ray emission position. The first and second UAVs then perform joint positioning of the target point through time difference positioning and direction finding positioning. The transmitter emits rays to the flat panel detector, which receives the ray signal and converts it into an electrical signal. The signal is then relayed back to the ground control terminal via a second UAV for testing of the line crimping hardware.

[0008] In one implementation of the first aspect of the present invention, time difference positioning includes: The transmitter of the second UAV emits detection rays at a preset frequency and records the emission time. ; The first drone's flat-panel detector receives the X-ray signal and records the moment of reception. Calculate the time difference ; The real-time position coordinates of the two drones are obtained. Assume the real-time position of the first drone is... The real-time location of the second drone is Combined with the speed of electromagnetic wave propagation The coordinates of the target point are calculated using the hyperbolic positioning algorithm. ,satisfy: .

[0009] This invention, through the specific implementation of time-difference positioning, transforms "time difference" into "spatial location information," providing a precise quantitative basis for target point positioning. Instead of relying on position data from a single sensor, it combines the real-time positions of two UAVs with the electromagnetic wave propagation characteristics, using a hyperbolic algorithm to deduce the target coordinates. This method effectively avoids the limitations of single positioning methods. For example, it eliminates the need for clear target identification using visual sensors; the target can be locked simply by correlating the time difference with spatial coordinates. This ensures accurate determination of the target's position even under poor visual conditions (such as insufficient light), laying the foundation for accurate subsequent X-ray emission and reducing detection omissions or misjudgments caused by positioning errors.

[0010] As a further limitation of the first aspect of the present invention, the direction finding and positioning includes: The first UAV's visual sensor images the target area, identifies target points using the SIFT feature matching algorithm, and calculates the azimuth angle of the target point relative to the first UAV using IMU data. and pitch angle ; Based on the real-time location of the first UAV Real-time location of the second drone Calculate the baseline vector of the line connecting the first and second UAVs, and combine it with the azimuth angle. and pitch angle The target coordinates are calculated using trigonometric relationships: Horizontal distance of the target point relative to the first UAV ; in, The angle between the line connecting the two aircraft and due north is given. The baseline length is calculated from the real-time position coordinates of the two machines and is the modulus of the baseline vector.

[0011] This invention supplements the accuracy of target positioning by using direction finding, adding a "directional dimension" and forming an effective synergy with time-of-flight positioning. Its technical advantages are reflected in the fact that, by leveraging SIFT feature matching from a visual sensor, it can accurately identify specific targets such as hardware fittings. Combined with IMU data, it calculates azimuth and pitch angles, allowing positioning to focus from a "fuzzy range" to a "specific target." Simultaneously, by utilizing the baseline vectors and trigonometric relationships of the dual UAV positions, angular information is converted into distance and coordinates, enabling target locking even under some environmental interference (such as slight electromagnetic interference affecting position signals). This positioning method is particularly suitable for the precise capture of small targets such as line hardware fittings, improving the specificity and accuracy of target positioning.

[0012] As a further limitation of the first aspect of the present invention, the real-time positions of the first UAV and the second UAV are determined using a fusion positioning method, including: The GPS positioning results, IMU positioning results, and visual positioning results are obtained. When the GPS signal strength is greater than a set threshold, the weight ratio of the GPS positioning results, IMU positioning results, and visual positioning results is 6:2:2. When the GPS signal strength is less than or equal to a set threshold, the weight ratio of GPS positioning results, IMU positioning results, and visual positioning results is 5:4:1. The real-time positions of the first and second UAVs are determined based on the obtained weights.

[0013] This invention overcomes the limitations of single positioning methods in complex environments through dynamic weight adjustment-based fusion positioning, achieving "adaptive optimization" of positioning reliability. Positioning weights are flexibly allocated based on GPS signal strength: when GPS signal is strong, its high accuracy is prioritized; when GPS is obstructed (e.g., by trees or power poles), the weights of IMU and visual positioning are automatically increased, utilizing IMU's short-term trajectory estimation and visual recognition of ground landmarks to compensate for the decrease in GPS accuracy. This dynamic adjustment ensures that the real-time position of the two UAVs remains accurate at all times, providing stable position support for joint positioning and mission synchronization regardless of whether the detection environment is open airspace or complex terrain, avoiding detection interruptions or deviations due to positioning failures.

[0014] In one implementation of the first aspect of the present invention, maintaining time synchronization according to time synchronization parameters includes: The ground control terminal is equipped with a PTP master clock, and the first and second UAVs are each equipped with a PTP slave clock. The PTP slave clocks are synchronized with the PTP master clock via a wireless local area network. Using the synchronization message of the PTP master clock as the time synchronization parameter, each synchronization process includes: the PTP master clock sending a synchronization message, the PTP slave clock receiving and recording the timestamp, and the PTP slave clock calculating the deviation and calibrating the local clock so that the clock deviation between the first UAV and the second UAV is less than a set threshold.

[0015] This invention eliminates errors in dual-UAV collaboration at the "time source" through a PTP master-slave clock time synchronization mechanism, establishing a precise benchmark for end-to-end collaboration. Real-time calibration of the ground master clock and the UAV slave clock ensures that clock deviations between the two UAVs are kept within a minimal range, avoiding a chain reaction of problems caused by time asynchrony, such as measurement errors in transmission and reception times during time difference positioning, and mismatched spatiotemporal tags during data transmission. Simultaneously, the wireless LAN synchronization method guarantees real-time performance, allowing time calibration to be dynamically performed throughout the detection process. This ensures that the two UAVs maintain time consistency at every stage of flight, positioning, and detection, improving the accuracy of collaborative actions and reducing invalid detection data or positioning errors caused by time differences.

[0016] In one implementation of the first aspect of the present invention, the ground control terminal generates the initial detection path for the first UAV and the second UAV based on the three-dimensional map of the detection area, the endurance time of the first UAV and the second UAV, and the task priority.

[0017] This invention generates an initial path by combining multiple factors through a ground terminal, achieving "proactive optimization" of the detection path and improving detection efficiency and safety from the source. Path planning is no longer a simple "straight-line arrival," but comprehensively considers three-dimensional obstacles in the detection area (such as poles and trees), UAV endurance limitations (avoiding mid-flight return), and task priorities (prioritizing the detection of high-risk hardware), ensuring that the initial path is both safe and efficient. This planning method avoids the risk of collisions caused by unreasonable UAV paths, reduces the wasted endurance during ineffective flights, and prioritizes important detection tasks, improving overall detection efficiency and ensuring that key areas are detected within limited endurance, reducing increased detection costs or task delays caused by path problems.

[0018] In one implementation of the first aspect of the present invention, when the first UAV detects a suspected defect, the ground control terminal sends an instruction to the second UAV to adjust the flight trajectory of the second UAV to the optimal ray emission position, and simultaneously triggers the detection actions of the transmitter and the flat panel detector.

[0019] This invention achieves "real-time response" in the detection process by dynamically adjusting tasks triggered by suspected defects, thus improving the efficiency and accuracy of defect detection. Breaking away from the traditional "fixed-path detection" model, when the first UAV detects a suspected defect, the ground terminal can quickly instruct the second UAV to adjust its trajectory to the optimal ray emission position, simultaneously triggering ray and detection actions. This dynamic response avoids the problem of "missing the optimal detection opportunity." For example, it eliminates the need to wait for the second UAV to complete its current path and then turn back, allowing it to immediately focus on the defect area. Through precise ray angle and detection coordination, clearer defect data is obtained, reducing missed defects due to improper detection positions. Simultaneously, it shortens the defect detection response time, improving the overall accuracy and efficiency of detection.

[0020] In one implementation of the first aspect of the present invention, the first UAV and the second UAV exchange their respective position information in real time. When the distance between the first UAV and the second UAV is less than a safety threshold, the dual-UAV emergency obstacle avoidance is automatically triggered, and the flight direction of the first UAV and / or the second UAV is adjusted.

[0021] This invention constructs an "active safety protection" system for the detection process through real-time interaction and obstacle avoidance between two drones, thus resolving the collision risk of collaborative flight. By exchanging position information in real time, the two drones can dynamically sense their distance from each other. Once the distance falls below a safety threshold, an obstacle avoidance algorithm is immediately triggered to adjust their flight direction and prevent collisions. Simultaneously, this position monitoring can also indirectly avoid collisions between drones and power transmission lines (because distance monitoring can be extended to determine the distance to the power lines). This mechanism effectively compensates for the lack of autonomous obstacle avoidance in traditional detection methods, protecting drone equipment safety, preventing detection interruptions due to collisions, avoiding damage to power lines by drones, ensuring line operation safety, and improving the overall safety of the detection process.

[0022] In one implementation of the first aspect of the present invention, a second UAV is used to carry a flat panel detector, a signal receiving and transmission device, and a transmitter mounted on the first UAV in the air. The signal receiving and transmission device is used to receive ground control signals and transmit the final detection data back to the ground control terminal.

[0023] By centrally mounting signal-related equipment on a second UAV, an "anti-interference signal transmission link" was constructed, solving the signal interference problem in the live environment of power transmission lines. Integrating a flat panel detector, signal receiving and transmission equipment into the second UAV ensures stable reception of X-ray signals from the first UAV transmitter, while also receiving ground control signals through dedicated equipment and reliably transmitting detection data back. This design effectively filters out electromagnetic interference generated by live conductors of power transmission lines, preventing signal loss or distortion. It ensures accurate transmission of ground control commands and complete transmission of detection data (such as X-ray images) in high-voltage live detection scenarios, breaking through the signal bottleneck of traditional detection in live environments and improving the feasibility and data reliability of detection in complex electromagnetic environments.

[0024] Secondly, the present invention provides a dual-UAV synchronous control system for testing line crimp fittings.

[0025] A dual-UAV synchronous control system for testing line crimping fittings includes a ground control terminal and a first UAV and a second UAV that communicate with the ground control terminal respectively. The first UAV is used to hoist a flat panel detector, and the second UAV is used to hoist a transmitter that works with the flat panel detector. Based on the 3D map of the detection area, the endurance time of the first and second UAVs, and the task priority, the ground control terminal generates the initial detection paths for the first and second UAVs, and the PTP master clock on the ground control terminal generates time synchronization parameters. The first and second UAVs respectively receive the initial path detection and time synchronization parameters from the ground control terminal; The first and second UAVs flew along their respective initial detection paths and maintained time synchronization according to the time synchronization parameters. Upon reaching the detection area, the first UAV adjusts to the detection position, and the second UAV adjusts to the ray emission position. The first and second UAVs then perform joint positioning of the target point through time difference positioning and direction finding positioning. The transmitter emits rays to the flat panel detector, which receives the ray signal and converts it into an electrical signal. The signal is then relayed back to the ground control terminal via a second UAV for testing of the line crimping hardware.

[0026] Compared with the prior art, the beneficial effects of the present invention are: This invention innovatively proposes a dual-UAV synchronous control method for inspecting line crimp fittings. It constructs a complete inspection process that coordinates the two UAVs with a ground terminal. From initial path planning and time synchronization to joint positioning and signal feedback, it automates the entire inspection process, eliminating the reliance on manual visual alignment in traditional inspections. Time synchronization ensures the coordinated movement of the two UAVs, and time difference and direction finding are used for joint positioning to ensure accurate target acquisition. The data transmission link problem is solved by relaying signals from the second UAV. The overall process avoids the risks of line contact and UAV failure caused by human operation errors, and improves the orderliness and continuity of inspection. It transforms the two UAVs from "operating independently" to "collaborative linkage", significantly enhancing the automation level and safety reliability of line crimp fitting inspection.

[0027] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0029] Figure 1 This is a flowchart illustrating a dual-UAV synchronous control method for detecting line crimp fittings, provided as an exemplary embodiment of the present invention. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0032] This implementation proposes a dual-UAV synchronous control method for inspecting line crimping fittings. It is mainly applied to the live-line inspection scenario of digital radiographic nondestructive testing of crimping quality of high-voltage transmission line fittings. By using two UAVs (denoted as UAV A and UAV B) to work together, high-precision inspection of transmission line defects can be achieved. Here, UAV A is the first UAV and UAV B is the second UAV. Specifically, a dual-UAV synchronous control system for inspecting line crimp fittings was designed. More specifically, UAV A is equipped with a digital X-ray flat panel detector, a high-precision GPS module (positioning accuracy ≤10cm), an inertial measurement unit (IMU, sampling frequency 100Hz), a vision sensor (resolution 1920×1080, frame rate 30fps), and a wireless communication module (supporting 5G / 4G dual-mode communication); UAV B is equipped with a X-ray transmitter (operating voltage 18V, X-ray intensity adjustable), signal receiving / return transmission equipment (including anti-interference filter), a high-precision GPS module, an IMU, a vision sensor, and a wireless communication module; the ground control station (i.e., ground control terminal) consists of an industrial computer, a display and control terminal, a data storage server, and a time synchronization server, and is responsible for the remote control, data processing, and task scheduling of the UAVs. The overall process is as follows: The ground control station plans the detection task, generates the initial paths and time synchronization parameters for UAVs A and B, and sends them down via wireless link; the two UAVs take off and fly along the preset paths, maintaining time synchronization via the PTP protocol during the flight, and achieving high-precision positioning by integrating GPS, IMU, and visual data; upon reaching the detection area, UAV A adjusts to the detection position, and UAV B enters the ray emission position according to the task scheduling instructions. The two UAVs jointly lock the target point through time difference positioning and direction finding positioning; UAV B emits a ray, which UAV A receives and converts into an electrical signal, which is relayed back to the ground control station via UAV B. During the process, anti-interference measures ensure signal stability; the ground control station performs data fusion analysis and generates a detection report; after the task is completed, the UAVs return along the original paths.

[0033] More specifically, the synchronization control method of the present invention, such as Figure 1 As shown, the process includes the following steps: initializing the map system, configuring task parameters (detection area / accuracy threshold), performing device self-test (sensor / communication module), setting the synchronization reference (PTP master clock calibration), followed by the coordinated takeoff of two UAVs; after takeoff, time difference positioning is implemented (including ray emission / reception timing, time difference). The process involves calculating coordinates using a hyperbolic algorithm, implementing direction finding and positioning (including visual sensor angle measurement, dual-machine baseline vector calculation, and triangulation), and optimizing fusion positioning (including multi-source data acquisition (GPS / IMU / visual), EKF filtering fusion, and dynamic weight adjustment) to output accurate target coordinates (error ≤ 5cm). Simultaneously, a synchronization control process is implemented, encompassing time synchronization (including real-time calibration using the PTP protocol, redundant backup of BeiDou timing, and clock deviation ≤ 500ns), task synchronization (including improved A* algorithm path planning, dynamic task allocation (defect priority), and collision avoidance (safe distance 25m)), and data synchronization (including spatiotemporal tagging (microsecond-level timestamps), MQTT protocol transmission, and distributed data). The system stores the data in a database and triggers collaborative detection actions (response latency ≤ 100ms). During this process, it also performs anti-signal interference procedures, including hardware anti-interference (including bandpass filter deployment, directional antenna pointing optimization, and isolation transformer power supply), signal transmission optimization (including frequency hopping technology (500 hops / second), OFDM modulation + FEC coding, data compression and encryption (AES-256)), and interference adaptive adjustment (including real-time SNR monitoring (5G / 4G), communication mode switching, and dynamic adjustment of transmission power) to ensure stable data transmission (success rate ≥ 99.5%). After that, it performs joint data analysis (image registration / defect identification), and then determines whether the task is completed. If not, it continues to the next round of positioning and detection; if completed, the drone returns to base.

[0034] In this implementation, time-difference positioning specifically includes: The ray emitter of UAV B emits detection rays at a preset frequency (e.g., 10Hz) and records the emission time t1 (synchronized by an onboard high-precision clock with an error ≤1ms).

[0035] The digital X-ray flat panel detector of UAV A receives X-ray signals and records the reception time. Calculate the time difference .

[0036] The ground control station acquires the real-time position coordinates of the two UAVs (via GPS and IMU fusion, sampling frequency 50Hz): Let the position of UAV A be... The location of drone B is Combined with the electromagnetic wave propagation speed c (3×10 8 (m / s), and use the hyperbolic positioning algorithm to calculate the coordinates of the target point (such as the location of a defect in transmission line fittings). ,satisfy: (1); In this implementation, direction finding and positioning specifically includes: The visual sensor of UAV A images the target area, identifies the target (such as a wire connector) using the SIFT feature matching algorithm, and calculates the target's azimuth angle relative to UAV A by combining IMU data. (Horizontal angle) and pitch angle .

[0037] Based on the real-time positions of UAVs A and B, the ground control station calculates the baseline vector of the line connecting the two UAVs, and, combined with the azimuth angles α and β, solves for the target coordinates using trigonometric relationships. Horizontal distance of the target relative to UAV A (2); in The angle between the line connecting the two aircraft and due north is given. It is calculated from the real-time position coordinates of the two machines.

[0038] In this implementation, UAV A and UAV B use a fusion positioning method to obtain their real-time positions, specifically including: The extended Kalman filter (EKF) algorithm is used to fuse multi-source data. The GPS positioning result is used as the initial value. When the GPS signal is blocked (such as when crossing a forest), short-term trajectory is calculated using IMU data (acceleration, angular velocity). At the same time, the visual sensor identifies ground landmarks (such as poles) and corrects the positioning result by combining them with a preset landmark coordinate library.

[0039] The fusion weights are dynamically adjusted. When the GPS signal is stable (signal-to-noise ratio ≥ 40dB), its weight is set to 0.6; the weights of IMU and visual positioning are 0.2 and 0.2, respectively; when the GPS signal is weak (signal-to-noise ratio < 20dB), the weight of visual positioning is increased to 0.5, the weight of IMU is 0.4, and the weight of GPS is 0.1.

[0040] In this implementation, the time synchronization control process includes: The ground control station is equipped with a PTP master clock (accuracy ±10ns), and UAVs A and B are equipped with PTP slave clock modules to achieve time synchronization through a wireless local area network (WLAN, frequency band 5.8GHz). The synchronization period is set to 1 second. Each synchronization process includes: the master clock sends a synchronization message → the slave clock receives and records the timestamp → the slave clock calculates the deviation and calibrates the local clock to ensure that the clock deviation between the two machines is ≤500ns.

[0041] This implementation also incorporates redundancy design, specifically including: when WLAN communication is interrupted, it automatically switches to BeiDou satellite time synchronization (synchronization accuracy ≤1μs) to ensure the continuity of time synchronization.

[0042] In this implementation, the task synchronization control process includes: The ground control station performs path planning based on the improved A* algorithm: inputting a 3D map of the detection area (including obstacle information), UAV endurance time (≥40min) and task priority (e.g., defect detection has a higher priority than regular inspection), and generating a cooperative path for UAVs A and B; Dynamic task allocation: When UAV A detects a suspected defect, the ground control station sends a command to UAV B to adjust its flight trajectory to the optimal ray emission position (3-5m from the target, angle ≤15° with the target normal), and simultaneously triggers ray emission and detection actions with a response delay ≤100ms.

[0043] Collision avoidance: The two aircraft exchange position information in real time (frequency 10Hz). When the distance is less than the safety threshold (5m), the obstacle avoidance algorithm (such as speed-based obstacle method) is automatically triggered to adjust the flight direction.

[0044] In this implementation, the data synchronization control process includes: The data collected by the drone (positioning information, image data, sensor data) are all marked with high-precision timestamps (accurate to the microsecond level) and location tags (latitude, longitude, and altitude); Data transmission is performed using the MQTT protocol, with the ground control station acting as the broker and UAVs A and B acting as publishers. Before data transmission, compression (such as JPEG2000 compressed image, compression ratio 10:1) and encryption (AES-256 algorithm) are performed. Data storage uses a distributed database (such as MongoDB), and organizes data by timestamp and location index to ensure that the detection data of the two drones correspond one-to-one in the spatiotemporal dimension, supporting subsequent joint analysis (such as the registration of ray images and visual images).

[0045] In this implementation, hardware anti-interference design was implemented. The signal receiving device of UAV B integrates a bandpass filter (center frequency 2.4GHz, bandwidth 50MHz) to filter out power frequency (50Hz) and harmonic interference from the transmission line. The X-ray machine power supply module uses an isolation transformer (isolation voltage ≥5kV) to prevent high-voltage signals from coupling to the communication link. The communication antennas of UAV A and UAV B use directional antennas (gain ≥8dBi) pointing towards the ground control station to reduce lateral electromagnetic interference (such as broadband noise generated by conductor corona discharge).

[0046] In this implementation, signal transmission optimization was performed. The ground control station's signal uses frequency hopping technology (500 hops / second, frequency band 2.4-2.4835GHz) to avoid fixed-frequency interference. Image data backhaul uses orthogonal frequency division multiplexing (OFDM) modulation combined with forward error correction coding (FEC, code rate 3 / 4) to ensure a bit error rate ≤10 when the signal-to-noise ratio is ≥10dB. -6 .

[0047] In this implementation, interference monitoring and adaptive adjustment are achieved. The UAV B monitors the signal-to-noise ratio (SNR) of the received signal in real time. When the SNR is less than 15dB, it automatically increases the transmission power (maximum 20dBm) and switches to the 5G communication mode with stronger anti-interference capability to ensure the stability of data transmission.

[0048] Through the above-described implementation method, this invention achieves high-precision positioning, efficient collaborative control, and resistance to strong electromagnetic interference in digital X-ray inspection of high-voltage transmission line fittings by dual unmanned aerial vehicles (UAVs). The inspection accuracy can reach ±5cm, and the data transmission success rate is ≥99.5%, meeting the inspection requirements in complex environments.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-UAV synchronous control method for inspecting line crimp fittings, characterized in that, The first UAV and the second UAV communicate with the ground control terminal respectively. The first UAV is used to hoist the flat panel detector, and the second UAV is used to hoist the transmitter that works with the flat panel detector. Includes the following processes: The first and second UAVs respectively receive the initial path detection and time synchronization parameters from the ground control terminal; The first and second UAVs flew along their respective initial detection paths and maintained time synchronization according to the time synchronization parameters. Upon reaching the detection area, the first UAV adjusts to the detection position, and the second UAV adjusts to the ray emission position. The first and second UAVs then perform joint positioning of the target point through time difference positioning and direction finding positioning. The transmitter emits rays to the flat panel detector, which receives the ray signal and converts it into an electrical signal. The signal is then relayed back to the ground control terminal via a second UAV for testing of the line crimping hardware.

2. The dual-UAV synchronous control method for testing line crimp fittings as described in claim 1, characterized in that, Time zone positioning, including: The transmitter of the second UAV emits detection rays at a preset frequency and records the emission time simultaneously. ; The first drone's flat-panel detector receives the X-ray signal and records the moment of reception. Calculate the time difference ; The real-time position coordinates of the two drones are obtained. Assume the real-time position of the first drone is... The real-time location of the second drone is Combined with the speed of electromagnetic wave propagation The coordinates of the target point are calculated using the hyperbolic positioning algorithm. ,satisfy: 。 3. The dual-UAV synchronous control method for testing line crimp fittings as described in claim 2, characterized in that, Direction finding and positioning, including: The first UAV's visual sensor images the target area, identifies target points using the SIFT feature matching algorithm, and calculates the azimuth angle of the target point relative to the first UAV using IMU data. and pitch angle ; Based on the real-time location of the first UAV Real-time location of the second drone Calculate the baseline vector of the line connecting the first and second UAVs, and combine it with the azimuth angle. and pitch angle The target coordinates are calculated using trigonometric relationships: Horizontal distance of the target point relative to the first UAV ; in, The angle between the line connecting the two aircraft and due north is given. The baseline length is calculated from the real-time position coordinates of the two machines and is the modulus of the baseline vector.

4. The dual-UAV synchronous control method for testing line crimp fittings as described in claim 3, characterized in that, The real-time positions of the first and second UAVs are determined using a fusion positioning method, including: The GPS positioning results, IMU positioning results, and visual positioning results are obtained. When the GPS signal strength is greater than a set threshold, the weight ratio of the GPS positioning results, IMU positioning results, and visual positioning results is 6:2:

2. When the GPS signal strength is less than or equal to a set threshold, the weight ratio of GPS positioning results, IMU positioning results, and visual positioning results is 5:4:

1. The real-time positions of the first and second UAVs are determined based on the obtained weights.

5. The dual-UAV synchronous control method for detecting line crimp fittings as described in any one of claims 1-4, characterized in that, Maintain time synchronization based on time synchronization parameters, including: The ground control terminal is equipped with a PTP master clock, and the first and second UAVs are each equipped with a PTP slave clock. The PTP slave clocks are synchronized with the PTP master clock via a wireless local area network. Using the synchronization message of the PTP master clock as the time synchronization parameter, each synchronization process includes: the PTP master clock sending a synchronization message, the PTP slave clock receiving and recording the timestamp, and the PTP slave clock calculating the deviation and calibrating the local clock so that the clock deviation between the first UAV and the second UAV is less than a set threshold.

6. The dual-UAV synchronous control method for detecting line crimp fittings as described in any one of claims 1-4, characterized in that, The ground control terminal generates the initial detection paths for the first and second UAVs based on the 3D map of the detection area, the endurance of the first and second UAVs, and their mission priorities.

7. The dual-UAV synchronous control method for testing line crimp fittings as described in any one of claims 1-4, characterized in that, When the first UAV detects a suspected defect, the ground control terminal sends a command to the second UAV to adjust its flight trajectory to the optimal ray emission position and simultaneously trigger the detection actions of the transmitter and the flat panel detector.

8. The dual-UAV synchronous control method for testing line crimp fittings as described in any one of claims 1-4, characterized in that, The first and second UAVs exchange their respective position information in real time. When the distance between the first and second UAVs is less than a safety threshold, the dual-UAV emergency obstacle avoidance is automatically triggered, and the flight direction of the first UAV and / or the second UAV is adjusted.

9. The dual-UAV synchronous control method for detecting line crimp fittings as described in any one of claims 1-4, characterized in that, The second UAV is equipped with a flat panel detector, signal receiving and transmission equipment. The flat panel detector receives the transmitter signal hoisted by the first UAV in the air. The signal receiving and transmission equipment is used to receive ground control signals and transmit the final detection data back to the ground control terminal.

10. A dual-UAV synchronous control system for inspecting line crimp fittings, characterized in that, It includes a ground control terminal and a first UAV and a second UAV that communicate with the ground control terminal respectively. The first UAV is used to hoist the flat panel detector, and the second UAV is used to hoist the transmitter that works with the flat panel detector. Based on the 3D map of the detection area, the endurance time of the first and second UAVs, and the task priority, the ground control terminal generates the initial detection paths for the first and second UAVs, and the PTP master clock on the ground control terminal generates time synchronization parameters. The first and second UAVs respectively receive the initial path detection and time synchronization parameters from the ground control terminal; The first and second UAVs flew along their respective initial detection paths and maintained time synchronization according to the time synchronization parameters. Upon reaching the detection area, the first UAV adjusts to the detection position, and the second UAV adjusts to the ray emission position. The first and second UAVs then perform joint positioning of the target point through time difference positioning and direction finding positioning. The transmitter emits rays to the flat panel detector, which receives the ray signal and converts it into an electrical signal. The signal is then relayed back to the ground control terminal via a second UAV for testing of the line crimping hardware.

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