Low-altitude inspection unmanned aerial vehicle flight path planning and obstacle avoidance method

Abstract

The application discloses a low-altitude inspection unmanned aerial vehicle flight path planning and obstacle avoidance method, relates to the path planning and obstacle avoidance field, and solves the problem that obstacles under different motion states cannot be effectively avoided. Distances between different inspection points are analyzed according to different inspection point coordinates, and multiple inspection trajectories in an inspection area are obtained. Distances of front obstacles are analyzed according to real-time flight speeds of the inspection unmanned aerial vehicle and irradiation time lengths of detection lasers. Motion types of the front obstacles are analyzed according to actual distances and calculated distances, and the motion types of the front obstacles are obtained as opposite motion, same direction motion or stationary. Interference states of different unmanned aerial vehicles in the inspection area are analyzed according to real-time inspection altitudes and preset flight altitudes. Flight process control of the inspection unmanned aerial vehicle is performed according to interference coordinates, real-time longitude and latitude coordinates and the motion types of the front obstacles, and the application realizes effective obstacle avoidance of obstacles under different motion states.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) path planning and obstacle avoidance, and relates to process control technology. Specifically, it is a method for flight path planning and obstacle avoidance of a low-altitude inspection UAV. Background Technology

[0002] With the large-scale deployment of power transmission, oil and gas pipelines, bridge infrastructure and wind power facilities, autonomous inspection technology based on unmanned aerial vehicles is gradually becoming the mainstream means of monitoring the condition of critical facilities due to its advantages of mobility, low cost and high accessibility. Currently, flight path planning for drones typically employs intelligent algorithms such as rapidly expanding random trees, various ant colony and particle swarm optimization algorithms. While these algorithms can accurately plan the drone's flight path, they also present challenges such as high computational load and performance requirements, leaving room for optimization in the drone's flight path planning speed. Furthermore, current obstacle avoidance technologies for drones during flight cannot accurately analyze the motion state of obstacles, making it difficult to effectively avoid obstacles in different motion states. Therefore, this invention proposes a method for flight path planning and obstacle avoidance of low-altitude inspection drones. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for flight path planning and obstacle avoidance for low-altitude inspection drones.

[0004] The technical problem to be solved by this invention is: How to effectively avoid obstacles in different motion states.

[0005] The objective of this invention can be achieved through the following technical solutions: A method for flight path planning and obstacle avoidance of a low-altitude inspection UAV, the method comprising: Step S1: Analyze the distance between different inspection points based on their coordinates to obtain multiple inspection trajectories within the inspection area. Step S2: Analyze the distance to the obstacle ahead based on the real-time flight speed of the inspection drone and the illumination duration of the detection laser, and obtain the actual distance and calculated distance between the inspection drone and the obstacle ahead. Step S3: Analyze the movement type of the obstacle in front based on the actual distance and the calculated distance. The analysis shows that the movement type of the obstacle in front is either moving in the opposite direction, moving in the same direction, or stationary. Step S4: Analyze the interference status of different UAVs in the inspection area based on the real-time inspection altitude and the preset flight altitude, and obtain the interfering UAVs, interference trajectory points and normal trajectory points in the inspection area. Step S5: Control the flight process of the inspection drone based on the interference coordinates, real-time latitude and longitude coordinates and the movement type of the obstacle in front.

[0006] Furthermore, the analysis process in step S1 includes the following sub-steps: Step S101: Obtain the coordinates of the inspection points of the inspection drone within the inspection area; Among them, the inspection point includes the inspection start point, the inspection end point and the inspection target point, and the inspection point coordinates include the coordinates of the inspection start point, the inspection end point and the inspection target point. Step S102: Calculate the first distance between the inspection starting point and different inspection target points within the inspection area using the distance formula, iterate through and compare different first distances to obtain the minimum value of the first distance, and record the inspection target point corresponding to the minimum value of the first distance as the first target point; Step S103: Calculate the second distance between the first target point and different inspection target points, iterate through and compare different second distances to obtain the minimum value of the second distance, and record the inspection target point corresponding to the minimum value of the second distance as the second target point; By analogy, the analysis yields the third target point, the fourth target point, ..., the nth target point, where n is the target point number; Step S104: The straight line trajectory between the inspection starting point and the first target point is taken as the first inspection trajectory of the inspection drone, the straight line trajectory between the first target point and the second target point is taken as the second inspection trajectory of the inspection drone, and so on, the straight line trajectory between the (n-1)th target point and the nth target point is taken as the nth inspection trajectory of the inspection drone, and the straight line trajectory between the nth target point and the inspection ending point is taken as the (n+1)th inspection trajectory of the inspection drone.

[0007] Furthermore, the analysis process in step S2 includes the following sub-steps: Step S201: The inspection drone emits a detection laser forward along the flight direction and records the corresponding time as the emission time. When the inspection drone receives the returned detection laser for the first time, the corresponding time is recorded as the first reception time. Step S202: Obtain the real-time flight speed of the inspection drone, subtract the transmission time from the first reception time to obtain the illumination duration of the detection laser, and multiply the illumination duration by the real-time flight speed to obtain the initial flight distance of the inspection drone during the detection laser illumination period. Step S203: Obtain the illumination speed of the detection laser, multiply the illumination speed by the illumination duration to obtain the illumination optical path of the detection laser, add the illumination optical path to the initial flight distance, divide by two to obtain the first value, and subtract the initial flight distance from the first value to obtain the first actual distance between the inspection drone and the obstacle in front at the first reception time. Similarly, when the inspection drone continuously receives the returned detection laser, the corresponding time is recorded as the second reception time, the third reception time, ..., the i-th reception time, where i is the number of the reception time. At the same time, the different actual distances between the inspection drone and the obstacle in front are calculated at different reception times. Among them, different actual distances include the second actual distance, the third actual distance, ..., the kth actual distance, where k is the number of the actual distance.

[0008] Furthermore, the analysis process in step S2 also includes the following sub-steps: Step S204: Subtract the first receiving time from the second receiving time to obtain the second flight time of the inspection drone; multiply the second flight time by the real-time flight speed to obtain the second flight distance of the inspection drone. By analogy, the different flight distances of the inspection drone can be calculated; Among them, different flight distances include the third flight distance, the fourth flight distance, ..., the m-th flight distance, where m is the number of the flight distance; Step S205: Subtract the second flight distance from the first actual distance of the inspection drone to obtain the second calculated distance between the inspection drone and the obstacle in front; subtract the third flight distance from the second actual distance of the inspection drone to obtain the third calculated distance between the inspection drone and the obstacle in front. By analogy, different calculated distances between the inspection drone and obstacles in front are obtained.

[0009] Furthermore, the analysis process in step S3 includes the following sub-steps: Step S301: Compare the second calculated distance and the second actual distance between the inspection drone and the obstacle in front; Step S302: If the second calculated distance between the inspection drone and the obstacle in front is greater than the second actual distance, the movement type of the obstacle in front is recorded as reciprocating movement, and the second actual distance is subtracted from the second calculated distance, divided by the second flight time and the absolute value is taken to obtain the movement speed of the obstacle in front. Step S303: If the second calculated distance between the inspection drone and the obstacle in front is less than the second actual distance, the movement type of the obstacle in front is recorded as moving in the same direction, and the second actual distance minus the second calculated distance is divided by the second flight time to obtain the movement speed of the obstacle in front. Step S304: If the second calculated distance between the inspection drone and the obstacle in front is equal to the second actual distance, then the motion type of the obstacle in front is recorded as stationary. Similarly, the calculated and actual distances between the inspection drone and obstacles in front are analyzed at different time points to obtain the movement type and speed of the obstacles in front at different time points.

[0010] Furthermore, the analysis process in step S4 includes the following sub-steps: Step S401: Obtain the real-time inspection altitude of the inspection drone and the preset flight altitude of all drones within the inspection area; Step S402: Compare the preset flight altitude of different drones in the inspection area with the real-time inspection altitude of the inspection drone; If the preset flight altitude of all drones in the inspection area is different from the real-time inspection altitude of the inspection drone, no operation will be performed. If any drone in the inspection area has the same preset flight altitude as the real-time inspection altitude of the inspection drone, then the corresponding drone will be recorded as an interfering drone. Step S403: Divide the inspection trajectory of the inspection drone into multiple trajectory points according to a fixed interval distance, obtain the latitude and longitude coordinates corresponding to different trajectory points and record them as trajectory point coordinates, and so on, obtain the latitude and longitude coordinates of the trajectory points corresponding to the interfering drones in the inspection area and record them as reference point coordinates. Step S404: Track points whose coordinates are the same as the reference point coordinates within the inspection area are recorded as interference track points, and the latitude and longitude coordinates of the interference track points are recorded as interference coordinates. Track points whose coordinates are different from the reference point coordinates within the inspection area are recorded as normal track points.

[0011] Furthermore, the control process in step S5 includes the following sub-steps: Step S501: Obtain the real-time latitude and longitude coordinates of the inspection drone and the interference coordinates of the interference trajectory points, and compare the real-time latitude and longitude coordinates of the inspection drone with the interference coordinates of the interference trajectory points. If the real-time latitude and longitude coordinates of the inspection drone are different from the interference coordinates of the interference trajectory point, then the flight process control of the inspection drone will be implemented. If the real-time latitude and longitude coordinates of the inspection drone are the same as the interference coordinates of the interference trajectory point, then proceed to step S502. Step S502: When the movement type of the obstacle in front is in the same direction, obtain the movement speed of the obstacle in front, set the real-time flight speed of the inspection drone to the movement speed of the obstacle in front, until the real-time latitude and longitude coordinates are the same as the latitude and longitude coordinates of the normal trajectory point. Step S503: When the movement type of the obstacle in front is either moving in the opposite direction or stationary, obtain the movement speed of the obstacle in front, the real-time flight speed of the inspection drone, the early warning obstacle avoidance distance of the inspection drone, and the actual distance between the inspection drone and the obstacle in front. Subtract the warning and obstacle avoidance distance from the actual distance and divide by the sum of the moving speed and the real-time flight speed to obtain the reaction time of the inspection drone. Add the time corresponding to the current time node to the reaction time and sum to obtain the reaction time of the inspection drone. Divide the actual distance by the sum of the moving speed and the real-time flight speed to obtain the collision duration of the inspection drone. Add the time corresponding to the current time point to the collision duration and sum them to obtain the collision time of the inspection drone. The inspection drone will rise or fall a fixed distance from its real-time inspection altitude before the reaction time, and return to its real-time inspection altitude after the collision time to continue inspection along the inspection trajectory.

[0012] Furthermore, the control process in step S501 includes the following sub-steps: Step S5011: When the movement type of the obstacle in front is in the same direction, obtain the movement speed of the obstacle in front, set the real-time flight speed of the inspection drone to the movement speed of the obstacle in front, and make the inspection drone continue to inspect along the inspection trajectory. Step S5012: When the movement type of the obstacle in front is either moving in the opposite direction or stationary, obtain the movement speed of the obstacle in front, the real-time flight speed of the inspection drone, and the actual distance between the inspection drone and the obstacle in front. Divide the actual distance by the sum of the moving speed and the real-time flight speed to obtain the collision duration of the inspection drone. Add the time corresponding to the current time point to the collision duration and sum them to obtain the collision time of the inspection drone. The inspection drone will immediately rise or fall a fixed distance at its real-time inspection altitude, and after the collision time, return to its real-time inspection altitude to continue inspection along the inspection trajectory.

[0013] Furthermore, the low-altitude inspection UAV flight path planning and obstacle avoidance method also includes the following steps: Step S6: Install an array laser emitting device on the inspection drone; Step S7: Identify the actual outline of obstacles encountered by the inspection drone based on the array laser emitting device.

[0014] Furthermore, the identification process in step S7 includes the following sub-steps: Step S71: During the inspection process, the inspection drone emits a characteristic laser forward. When the inspection drone receives the returned characteristic laser, it activates the array laser emitting device to emit all detection lasers. Step S72: Obtain the resolution of the detection laser emitted by the inspection drone and construct a square grid with the same resolution. At the same time, number the different square grids according to the laser numbering rules of the detection laser. When the inspection drone receives the returned detection laser, obtain the laser number of the corresponding detection laser and record it as the obstacle number. Step S73: Fill the square grid according to the obstacle number to obtain the planar scan pattern of the obstacle, obtain the emission time of the feature laser, and record the time corresponding to the return of the feature laser received by the inspection drone as the reception time. Subtract the emission time from the reception time to obtain the flight time of the inspection drone. Step S74: Obtain the real-time flight speed of the inspection drone, multiply the flight time by the real-time flight speed to obtain the flight distance of the inspection drone, multiply the irradiation speed of the feature laser by the flight time and add it to the flight distance to obtain a second value, divide the second value by two and subtract the flight distance to obtain the actual distance between the inspection drone and the encountered obstacle. Step S75: Obtain the scaling factor of the inspection drone at the actual distance, multiply the side length of the square network by the scaling factor to obtain the actual side length of the square grid, and record the planar scan pattern within the square grid as the actual outline of the obstacle encountered by the inspection drone.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention first analyzes the distance between different inspection points based on the coordinates of the inspection points, and obtains multiple inspection trajectories within the inspection area. Then, it analyzes the distance to the obstacle in front based on the real-time flight speed of the inspection drone and the illumination time of the detection laser, and obtains the actual distance and calculated distance between the inspection drone and the obstacle in front. This invention achieves accurate analysis of the actual distance between the inspection drone and the obstacle in front. 2. The present invention then analyzes the movement type of the obstacle in front based on the actual distance and the calculated distance. The analysis shows that the movement type of the obstacle in front is opposite movement, same-direction movement or stationary. Then, it analyzes the interference status of different UAVs in the inspection area based on the real-time inspection height and the preset flight height. Finally, it controls the flight process of the inspection UAV based on the interference coordinates, real-time latitude and longitude coordinates and the movement type of the obstacle in front, thereby realizing effective obstacle avoidance for obstacles in different movement states. 3. The present invention also sets up an array laser emitting device on the inspection drone, and identifies the actual outline of the obstacles encountered by the inspection drone through the array laser emitting device. The present invention achieves effective identification of the outline of the obstacles encountered by the inspection drone. Attached Figure Description

[0016] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0017] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a schematic diagram of the first actual distance in this invention; Figure 3 This is a schematic diagram of the second distance calculation method in this invention; Figure 4 This is a schematic diagram illustrating different second actual distances in this invention; Figure 5 This is another method flowchart of the present invention; Figure 6 This is a schematic diagram of the array laser emitting device in this invention; Figure 7 This is a schematic diagram of the inspection drone emitting a detection laser in this invention; Figure 8 This is a schematic diagram of the electronic device in this invention. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0019] Example 1, please refer to Figures 1-4 As shown, the technical solution provided by this invention is: a method for flight path planning and obstacle avoidance of a low-altitude inspection drone. This method first plans the inspection trajectory of the inspection drone based on the distance between different inspection points within the inspection area. Then, it analyzes the distance between the inspection drone and obstacles in front, and analyzes the movement type and speed of the obstacles. Simultaneously, it analyzes the flight altitude of different drones within the inspection area to obtain the interfering drones within the inspection area. Finally, it further adjusts the inspection altitude or inspection speed of the inspection drone based on its movement type. The specific method is as follows: Step S1: Analyze the distance between different inspection points based on their coordinates to obtain multiple inspection trajectories within the inspection area. In this embodiment, the analysis process in step S1 includes the following sub-steps: Step S101: Obtain the coordinates of the inspection points of the inspection drone within the inspection area; Among them, the inspection point includes the inspection start point, the inspection end point and the inspection target point, and the inspection point coordinates include the coordinates of the inspection start point, the inspection end point and the inspection target point. In this embodiment, the inspection task of the inspection drone records the latitude and longitude coordinates corresponding to the inspection point; Step S102: Calculate the first distance between the inspection starting point and different inspection target points within the inspection area using the distance formula, iterate through and compare different first distances to obtain the minimum value of the first distance, and record the inspection target point corresponding to the minimum value of the first distance as the first target point; Step S103: Calculate the second distance between the first target point and different inspection target points using the Vincenty formula, iterate through and compare different second distances to obtain the minimum value of the second distance, and record the inspection target point corresponding to the minimum value of the second distance as the second target point; By analogy, the analysis yields the third target point, the fourth target point, ..., the nth target point, where n is the target point number; In this embodiment, the Vincenty formula, due to its method of calculating the straight-line distance between two latitude and longitude coordinates, does not use the terms "first" and "second" in the first distance and second distance to indicate a specific magnitude relationship, but only to represent distance names; Step S104: Take the straight line trajectory between the inspection starting point and the first target point as the first inspection trajectory of the inspection drone, take the straight line trajectory between the first target point and the second target point as the second inspection trajectory of the inspection drone, and so on, take the straight line trajectory between the (n-1)th target point and the nth target point as the nth inspection trajectory of the inspection drone, and take the straight line trajectory between the nth target point and the inspection ending point as the (n+1)th inspection trajectory of the inspection drone. In this embodiment, the inspection drone starts from the inspection starting point, travels along the first inspection trajectory to the first target point, then starts from the first target point, flies along the second inspection trajectory to the second target point, and so on, finally starting from the nth target point and traveling along the (n+1)th inspection trajectory to the inspection endpoint.

[0020] Step S2: Analyze the distance to the obstacle ahead based on the real-time flight speed of the inspection drone and the illumination duration of the detection laser, and obtain the actual distance and calculated distance between the inspection drone and the obstacle ahead. In this embodiment, the analysis process in step S2 includes the following sub-steps: Step S201: The inspection drone emits a detection laser forward along the flight direction and records the corresponding time as the emission time. When the inspection drone receives the returned detection laser for the first time, the corresponding time is recorded as the first reception time. Step S202: Obtain the real-time flight speed of the inspection drone, subtract the transmission time from the first reception time to obtain the illumination duration of the detection laser, and multiply the illumination duration by the real-time flight speed to obtain the initial flight distance of the inspection drone during the detection laser illumination period. Step S203: Obtain the illumination speed of the detection laser, multiply the illumination speed by the illumination duration to obtain the illumination optical path of the detection laser, add the illumination optical path to the initial flight distance, divide by two to obtain the first value, and subtract the initial flight distance from the first value to obtain the first actual distance between the inspection drone and the obstacle in front at the first reception time. Similarly, when the inspection drone continuously receives the returned detection laser, the corresponding time is recorded as the second reception time, the third reception time, ..., the i-th reception time, where i is the number of the reception time. At the same time, the different actual distances between the inspection drone and the obstacle in front are calculated at different reception times. Among them, different actual distances include the second actual distance, the third actual distance, ..., the kth actual distance, where k is the number of the actual distance; Please see Figure 2 As shown, when the inspection drone receives the returned detection laser, the inspection drone has continued to fly forward at the initial flight distance. The first value calculated at this time represents the distance between the inspection drone and the obstacle in front when it emitted the detection laser. Subtracting the initial flight distance from the first value gives the first actual distance. It should be explained that when the inspection drone receives the detection laser at discontinuous times, the time when the detection laser is received is recorded as the first receiving time, and the same subsequent analysis is performed. Step S204: Subtract the first receiving time from the second receiving time to obtain the second flight time of the inspection drone; multiply the second flight time by the real-time flight speed to obtain the second flight distance of the inspection drone. By analogy, the different flight distances of the inspection drone can be calculated; Among them, different flight distances include the third flight distance, the fourth flight distance, ..., the m-th flight distance, where m is the number of the flight distance; Step S205: Subtract the second flight distance from the first actual distance of the inspection drone to obtain the second calculated distance between the inspection drone and the obstacle in front; subtract the third flight distance from the second actual distance of the inspection drone to obtain the third calculated distance between the inspection drone and the obstacle in front. By analogy, different calculated distances between the inspection drone and obstacles in front are obtained; It should be explained that the calculated distance is based on the assumption that the obstacle in front is stationary. Subsequent steps require judging whether the assumption holds true based on the relationship between the calculated distance and the actual distance, thereby determining the direction and speed of the obstacle's movement. Please see Figure 3 As shown, the second calculated distance between the inspection drone and the obstacle in front is obtained by subtracting the second flight distance from the first actual distance.

[0021] Step S3: Analyze the movement type of the obstacle in front based on the actual distance and the calculated distance. The analysis shows that the movement type of the obstacle in front is either moving in the opposite direction, moving in the same direction, or stationary. In this embodiment, the analysis process in step S3 includes the following sub-steps: Step S301: Compare the second calculated distance and the second actual distance between the inspection drone and the obstacle in front; Step S302: If the second calculated distance between the inspection drone and the obstacle in front is greater than the second actual distance, the movement type of the obstacle in front is recorded as reciprocating movement, and the second actual distance is subtracted from the second calculated distance, divided by the second flight time and the absolute value is taken to obtain the movement speed of the obstacle in front. Step S303: If the second calculated distance between the inspection drone and the obstacle in front is less than the second actual distance, the movement type of the obstacle in front is recorded as moving in the same direction, and the second actual distance minus the second calculated distance is divided by the second flight time to obtain the movement speed of the obstacle in front. Step S304: If the second calculated distance between the inspection drone and the obstacle in front is equal to the second actual distance, then the motion type of the obstacle in front is recorded as stationary. Similarly, the calculated and actual distances between the inspection drone and obstacles in front are analyzed at different time points to obtain the movement type and speed of the obstacles in front at different time points. Please see Figure 4 As shown, when the second actual distance is the same as the second calculated distance, it means that the obstacle in front is not moving; when the second actual distance is greater than the second calculated distance, it means that the obstacle in front moves in the same direction as the inspection drone; when the second actual distance is less than the second calculated distance, it means that the obstacle in front moves in the opposite direction to the inspection drone.

[0022] Step S4: Analyze the interference status of different UAVs in the inspection area based on the real-time inspection altitude and the preset flight altitude, and obtain the interfering UAVs, interference trajectory points and normal trajectory points in the inspection area. In this embodiment, the analysis process in step S4 includes the following sub-steps: Step S401: Obtain the real-time inspection altitude of the inspection drone and the preset flight altitude of all drones within the inspection area; In this embodiment, all drones within the inspection area must report to the relevant platform before taking flight, and the reporting content includes flight trajectory and flight altitude; Step S402: Compare the preset flight altitude of different drones in the inspection area with the real-time inspection altitude of the inspection drone; If the preset flight altitude of all drones in the inspection area is different from the real-time inspection altitude of the inspection drone, no operation will be performed. If any drone in the inspection area has the same preset flight altitude as the real-time inspection altitude of the inspection drone, then the corresponding drone will be recorded as an interfering drone. Step S403: Divide the inspection trajectory of the inspection drone into multiple trajectory points according to a fixed interval distance, obtain the latitude and longitude coordinates corresponding to different trajectory points and record them as trajectory point coordinates, and so on, obtain the latitude and longitude coordinates of the trajectory points corresponding to the interfering drones in the inspection area and record them as reference point coordinates. In this embodiment, multiple trajectory points are selected on the inspection trajectory of the inspection drone to complete the discretization of the trajectory; Step S404: Track points whose coordinates are the same as the reference point coordinates within the inspection area are recorded as interference track points, and the latitude and longitude coordinates of the interference track points are recorded as interference coordinates. Track points whose coordinates are different from the reference point coordinates within the inspection area are recorded as normal track points.

[0023] Step S5: Control the flight process of the inspection drone based on the interference coordinates, real-time latitude and longitude coordinates, and the movement type of the obstacle in front; In this embodiment, the control process in step S5 includes the following sub-steps: Step S501: Obtain the real-time latitude and longitude coordinates of the inspection drone and the interference coordinates of the interference trajectory points, and compare the real-time latitude and longitude coordinates of the inspection drone with the interference coordinates of the interference trajectory points. If the real-time latitude and longitude coordinates of the inspection drone are different from the interference coordinates of the interference trajectory point, then the flight process control of the inspection drone will be implemented. If the real-time latitude and longitude coordinates of the inspection drone are the same as the interference coordinates of the interference trajectory point, then proceed to step S502. In this embodiment, the control process in step S501 includes the following sub-steps: Step S5011: When the movement type of the obstacle in front is in the same direction, obtain the movement speed of the obstacle in front, set the real-time flight speed of the inspection drone to the movement speed of the obstacle in front, and make the inspection drone continue to inspect along the inspection trajectory. Step S5012: When the movement type of the obstacle in front is either moving in the opposite direction or stationary, obtain the movement speed of the obstacle in front, the real-time flight speed of the inspection drone, and the actual distance between the inspection drone and the obstacle in front. Divide the actual distance by the sum of the moving speed and the real-time flight speed to obtain the collision duration of the inspection drone. Add the time corresponding to the current time point to the collision duration and sum them to obtain the collision time of the inspection drone. The inspection drone will immediately rise or fall a fixed distance at the real-time inspection altitude, and return to the real-time inspection altitude after the collision time to continue the inspection along the inspection trajectory. It should be explained that when the obstacle in front is stationary, the speed of the obstacle in front is zero. Step S502: When the movement type of the obstacle in front is in the same direction, obtain the movement speed of the obstacle in front, set the real-time flight speed of the inspection drone to the movement speed of the obstacle in front, until the real-time latitude and longitude coordinates are the same as the latitude and longitude coordinates of the normal trajectory point. Specifically, when the real-time latitude and longitude coordinates are the same as those of the normal trajectory point, the real-time flight speed is reset to the value before adjustment. Step S503: When the movement type of the obstacle in front is either moving in the opposite direction or stationary, obtain the movement speed of the obstacle in front, the real-time flight speed of the inspection drone, the early warning obstacle avoidance distance of the inspection drone, and the actual distance between the inspection drone and the obstacle in front. Subtract the warning and obstacle avoidance distance from the actual distance and divide by the sum of the moving speed and the real-time flight speed to obtain the reaction time of the inspection drone. Add the time corresponding to the current time node to the reaction time and sum to obtain the reaction time of the inspection drone. Divide the actual distance by the sum of the moving speed and the real-time flight speed to obtain the collision duration of the inspection drone. Add the time corresponding to the current time point to the collision duration and sum them to obtain the collision time of the inspection drone. It should be explained that if the real-time latitude and longitude coordinates of the inspection drone are the same as the interference coordinates of the interference trajectory point, it means that the obstacle in front is an interfering drone. The warning obstacle avoidance distance indicates that when the inspection drone reaches a certain distance from the obstacle in front, the inspection drone will issue a warning. The warning obstacle avoidance distance can be obtained from the specifications of the inspection drone. The inspection drone will rise or fall a fixed distance from its real-time inspection altitude before the reaction time, and return to its real-time inspection altitude after the collision time to continue inspection along the inspection trajectory. In this embodiment, after the real-time inspection altitude rises or falls by a fixed distance, the altitude of the inspection drone cannot encroach on the preset flight altitude of other drones within the area map.

[0024] Example 2, as Figure 5-7 As shown, this embodiment also provides a method for flight path planning and obstacle avoidance of a low-altitude inspection UAV. This method analyzes the outline of obstacles encountered by the inspection UAV using laser detection. In this method, an array of laser emitters is located in front of the inspection UAV, capable of simultaneously emitting multiple laser beams. Each laser beam has a unique laser number. The specific method is as follows: Step S6: Install an array laser emitting device on the inspection drone; The array laser emitting device is composed of multiple laser emitters. Each laser emitter can emit a probe laser. The probe laser emitted from the center position of the array laser emitting device is called the characteristic laser. Therefore, the array laser emitting device consists of a set of characteristic lasers and multiple sets of probe lasers. Step S7: Identify the actual outline of obstacles encountered by the inspection drone based on the array laser emitting device; In this embodiment, the identification process in step S7 includes the following sub-steps: Step S71: During the inspection process, the inspection drone emits a characteristic laser forward. When the inspection drone receives the returned characteristic laser, it activates the array laser emitting device to emit all detection lasers. Step S72: Obtain the resolution of the detection laser emitted by the inspection drone and construct a square grid with the same resolution. At the same time, number the different square grids according to the laser numbering rules of the detection laser. When the inspection drone receives the returned detection laser, obtain the laser number of the corresponding detection laser and record it as the obstacle number. For example, if the laser numbering rule for detecting lasers is to be recorded as first laser, second laser, ..., jth laser from left to right and top to bottom, then the square grid is also recorded as first grid, second grid, ..., jth grid from left to right and top to bottom. Step S73: Fill the square grid according to the obstacle number to obtain the planar scan pattern of the obstacle, obtain the emission time of the feature laser, and record the time corresponding to the return of the feature laser received by the inspection drone as the reception time. Subtract the emission time from the reception time to obtain the flight time of the inspection drone. Step S74: Obtain the real-time flight speed of the inspection drone, multiply the flight time by the real-time flight speed to obtain the flight distance of the inspection drone, multiply the irradiation speed of the feature laser by the flight time and add it to the flight distance to obtain a second value, divide the second value by two and subtract the flight distance to obtain the actual distance between the inspection drone and the encountered obstacle. Step S75: Obtain the scaling factor of the inspection drone at the actual distance, multiply the side length of the square network by the scaling factor to obtain the actual side length of the square grid, and record the planar scan pattern within the square grid as the actual outline of the obstacle encountered by the inspection drone. It should be explained that the scaling factor can be obtained from the internal parameters of the inspection drone. The scaling factor represents the scaling factor of the planar scan image obtained by the inspection drone relative to the actual image.

[0025] Example 3: This embodiment of the invention also provides an electronic device for running the aforementioned low-altitude inspection UAV flight path planning and obstacle avoidance method; see also... Figure 8 The schematic diagram of an electronic device provided by the embodiment of the present invention shown above includes a memory and a processor. The memory is used to store one or more computer instructions, and the one or more computer instructions are executed by the processor to realize the above-mentioned method for flight path planning and obstacle avoidance of a low-altitude inspection UAV. Furthermore, Figure 8 The electronic device shown also includes a communication bus and a communication interface, with the processor, communication interface and memory connected via the communication bus; The memory may include high-speed random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc. The communication bus can be an ISA bus, PCI bus, or EISA bus, etc. The communication bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 8 The symbol is represented by only one double-headed arrow, but this does not mean that there is only one communication bus or one type of communication bus. The processor may be an integrated circuit chip with signal processing capabilities. In implementation, the steps of the above methods can be completed by integrated logic circuits in the processor's hardware or by software instructions. The processor can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the method described in the foregoing embodiments.

[0026] Example 4: This embodiment of the invention also provides a computer storage medium storing computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions cause the processor to implement the above-described method for flight path planning and obstacle avoidance of a low-altitude inspection UAV. For specific implementation, please refer to the method embodiment, which will not be repeated here. The computer program product of the low-altitude inspection UAV flight path planning and obstacle avoidance method provided in the embodiments of the present invention includes a computer storage medium storing program code. The instructions included in the program code can be used to execute the methods in the preceding method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

[0027] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and / or device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0028] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0029] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for flight path planning and obstacle avoidance of a low-altitude inspection UAV, characterized in that, The methods include: Step S1: Analyze the distance between different inspection points based on their coordinates to obtain multiple inspection trajectories within the inspection area. Step S2: Analyze the distance to the obstacle ahead based on the real-time flight speed of the inspection drone and the illumination duration of the detection laser, and obtain the actual distance and calculated distance between the inspection drone and the obstacle ahead. Step S3: Analyze the movement type of the obstacle in front based on the actual distance and the calculated distance. The analysis shows that the movement type of the obstacle in front is either moving in the opposite direction, moving in the same direction, or stationary. Step S4: Analyze the interference status of different UAVs in the inspection area based on the real-time inspection altitude and the preset flight altitude, and obtain the interfering UAVs, interference trajectory points and normal trajectory points in the inspection area. Step S5: Control the flight process of the inspection drone based on the interference coordinates, real-time latitude and longitude coordinates and the movement type of the obstacle in front.

2. The method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 1, characterized in that, The analysis process in step S1 includes the following sub-steps: Step S101: Obtain the coordinates of the inspection points of the inspection drone within the inspection area; Among them, the inspection point includes the inspection start point, the inspection end point and the inspection target point, and the inspection point coordinates include the coordinates of the inspection start point, the inspection end point and the inspection target point. Step S102: Calculate the first distance between the inspection starting point and different inspection target points within the inspection area using the distance formula, iterate through and compare different first distances to obtain the minimum value of the first distance, and record the inspection target point corresponding to the minimum value of the first distance as the first target point; Step S103: Calculate the second distance between the first target point and different inspection target points, iterate through and compare different second distances to obtain the minimum value of the second distance, and record the inspection target point corresponding to the minimum value of the second distance as the second target point; By analogy, the analysis yields the third target point, the fourth target point, ..., the nth target point, where n is the target point number; Step S104: The straight line trajectory between the inspection starting point and the first target point is taken as the first inspection trajectory of the inspection drone, the straight line trajectory between the first target point and the second target point is taken as the second inspection trajectory of the inspection drone, and so on, the straight line trajectory between the (n-1)th target point and the nth target point is taken as the nth inspection trajectory of the inspection drone, and the straight line trajectory between the nth target point and the inspection ending point is taken as the (n+1)th inspection trajectory of the inspection drone.

3. The method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 1, characterized in that, The analysis process in step S2 includes the following sub-steps: Step S201: The inspection drone emits a detection laser forward along the flight direction and records the corresponding time as the emission time. When the inspection drone receives the returned detection laser for the first time, the corresponding time is recorded as the first reception time. Step S202: Obtain the real-time flight speed of the inspection drone, subtract the transmission time from the first reception time to obtain the illumination duration of the detection laser, and multiply the illumination duration by the real-time flight speed to obtain the initial flight distance of the inspection drone during the detection laser illumination period. Step S203: Obtain the illumination speed of the detection laser, multiply the illumination speed by the illumination duration to obtain the illumination optical path of the detection laser, add the illumination optical path to the initial flight distance, divide by two to obtain the first value, and subtract the initial flight distance from the first value to obtain the first actual distance between the inspection drone and the obstacle in front at the first reception time. Similarly, when the inspection drone continuously receives the returned detection laser, the corresponding time is recorded as the second reception time, the third reception time, ..., the i-th reception time, where i is the number of the reception time. At the same time, the different actual distances between the inspection drone and the obstacle in front are calculated at different reception times. Among them, different actual distances include the second actual distance, the third actual distance, ..., the kth actual distance, where k is the number of the actual distance.

4. The method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 3, characterized in that, The analysis process in step S2 also includes the following sub-steps: Step S204: Subtract the first receiving time from the second receiving time to obtain the second flight time of the inspection drone; multiply the second flight time by the real-time flight speed to obtain the second flight distance of the inspection drone. By analogy, the different flight distances of the inspection drone can be calculated; Among them, different flight distances include the third flight distance, the fourth flight distance, ..., the m-th flight distance, where m is the number of the flight distance; Step S205: Subtract the second flight distance from the first actual distance of the inspection drone to obtain the second calculated distance between the inspection drone and the obstacle in front; subtract the third flight distance from the second actual distance of the inspection drone to obtain the third calculated distance between the inspection drone and the obstacle in front. By analogy, different calculated distances between the inspection drone and obstacles in front are obtained.

5. The method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 1, characterized in that, The analysis process in step S3 includes the following sub-steps: Step S301: Compare the second calculated distance and the second actual distance between the inspection drone and the obstacle in front; Step S302: If the second calculated distance between the inspection drone and the obstacle in front is greater than the second actual distance, the movement type of the obstacle in front is recorded as reciprocating movement, and the second actual distance is subtracted from the second calculated distance, divided by the second flight time and the absolute value is taken to obtain the movement speed of the obstacle in front. Step S303: If the second calculated distance between the inspection drone and the obstacle in front is less than the second actual distance, the movement type of the obstacle in front is recorded as moving in the same direction, and the second actual distance minus the second calculated distance is divided by the second flight time to obtain the movement speed of the obstacle in front. Step S304: If the second calculated distance between the inspection drone and the obstacle in front is equal to the second actual distance, then the motion type of the obstacle in front is recorded as stationary. Similarly, the calculated and actual distances between the inspection drone and obstacles in front are analyzed at different time points to obtain the movement type and speed of the obstacles in front at different time points.

6. The method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 1, characterized in that, The analysis process in step S4 includes the following sub-steps: Step S401: Obtain the real-time inspection altitude of the inspection drone and the preset flight altitude of all drones within the inspection area; Step S402: Compare the preset flight altitude of different drones in the inspection area with the real-time inspection altitude of the inspection drone; If the preset flight altitude of all drones in the inspection area is different from the real-time inspection altitude of the inspection drone, no operation will be performed. If any drone in the inspection area has the same preset flight altitude as the real-time inspection altitude of the inspection drone, then the corresponding drone will be recorded as an interfering drone. Step S403: Divide the inspection trajectory of the inspection drone into multiple trajectory points according to a fixed interval distance, obtain the latitude and longitude coordinates corresponding to different trajectory points and record them as trajectory point coordinates, and so on, obtain the latitude and longitude coordinates of the trajectory points corresponding to the interfering drones in the inspection area and record them as reference point coordinates. Step S404: Track points whose coordinates are the same as the reference point coordinates within the inspection area are recorded as interference track points, and the latitude and longitude coordinates of the interference track points are recorded as interference coordinates. Track points whose coordinates are different from the reference point coordinates within the inspection area are recorded as normal track points.

7. The method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 1, characterized in that, The control process in step S5 includes the following sub-steps: Step S501: Obtain the real-time latitude and longitude coordinates of the inspection drone and the interference coordinates of the interference trajectory points, and compare the real-time latitude and longitude coordinates of the inspection drone with the interference coordinates of the interference trajectory points. If the real-time latitude and longitude coordinates of the inspection drone are different from the interference coordinates of the interference trajectory point, then the flight process control of the inspection drone will be implemented. If the real-time latitude and longitude coordinates of the inspection drone are the same as the interference coordinates of the interference trajectory point, then proceed to step S502. Step S502: When the movement type of the obstacle in front is in the same direction, obtain the movement speed of the obstacle in front, set the real-time flight speed of the inspection drone to the movement speed of the obstacle in front, until the real-time latitude and longitude coordinates are the same as the latitude and longitude coordinates of the normal trajectory point. Step S503: When the movement type of the obstacle in front is either moving in the opposite direction or stationary, obtain the movement speed of the obstacle in front, the real-time flight speed of the inspection drone, the early warning obstacle avoidance distance of the inspection drone, and the actual distance between the inspection drone and the obstacle in front. Subtract the warning and obstacle avoidance distance from the actual distance and divide by the sum of the moving speed and the real-time flight speed to obtain the reaction time of the inspection drone. Add the time corresponding to the current time node to the reaction time and sum to obtain the reaction time of the inspection drone. Divide the actual distance by the sum of the moving speed and the real-time flight speed to obtain the collision duration of the inspection drone. Add the time corresponding to the current time point to the collision duration and sum them to obtain the collision time of the inspection drone. The inspection drone will rise or fall a fixed distance from its real-time inspection altitude before the reaction time, and return to its real-time inspection altitude after the collision time to continue inspection along the inspection trajectory.

8. The method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 7, characterized in that, The control process in step S501 includes the following sub-steps: Step S5011: When the movement type of the obstacle in front is in the same direction, obtain the movement speed of the obstacle in front, set the real-time flight speed of the inspection drone to the movement speed of the obstacle in front, and make the inspection drone continue to inspect along the inspection trajectory. Step S5012: When the movement type of the obstacle in front is either moving in the opposite direction or stationary, obtain the movement speed of the obstacle in front, the real-time flight speed of the inspection drone, and the actual distance between the inspection drone and the obstacle in front. Divide the actual distance by the sum of the moving speed and the real-time flight speed to obtain the collision duration of the inspection drone. Add the time corresponding to the current time point to the collision duration and sum them to obtain the collision time of the inspection drone. The inspection drone will immediately rise or fall a fixed distance at its real-time inspection altitude, and after the collision time, return to its real-time inspection altitude to continue inspection along the inspection trajectory.

9. The method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 1, characterized in that, The low-altitude inspection UAV flight path planning and obstacle avoidance method also includes the following steps: Step S6: Install an array laser emitting device on the inspection drone; Step S7: Identify the actual outline of obstacles encountered by the inspection drone based on the array laser emitting device.

10. A method for flight path planning and obstacle avoidance of a low-altitude inspection UAV according to claim 9, characterized in that, The identification process in step S7 includes the following sub-steps: Step S71: During the inspection process, the inspection drone emits a characteristic laser forward. When the inspection drone receives the returned characteristic laser, it activates the array laser emitting device to emit all detection lasers. Step S72: Obtain the resolution of the detection laser emitted by the inspection drone and construct a square grid with the same resolution. At the same time, number the different square grids according to the laser numbering rules of the detection laser. When the inspection drone receives the returned detection laser, obtain the laser number of the corresponding detection laser and record it as the obstacle number. Step S73: Fill the square grid according to the obstacle number to obtain the planar scan pattern of the obstacle, obtain the emission time of the feature laser, and record the time corresponding to the return of the feature laser received by the inspection drone as the reception time. Subtract the emission time from the reception time to obtain the flight time of the inspection drone. Step S74: Obtain the real-time flight speed of the inspection drone, multiply the flight time by the real-time flight speed to obtain the flight distance of the inspection drone, multiply the irradiation speed of the feature laser by the flight time and add it to the flight distance to obtain a second value, divide the second value by two and subtract the flight distance to obtain the actual distance between the inspection drone and the encountered obstacle. Step S75: Obtain the scaling factor of the inspection drone at the actual distance, multiply the side length of the square network by the scaling factor to obtain the actual side length of the square grid, and record the planar scan pattern within the square grid as the actual outline of the obstacle encountered by the inspection drone.

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