Method for automatically planning imitated flight route of unmanned aerial vehicle

Abstract

The invention provides an automatic planning method for an imitated flight route of an unmanned aerial vehicle, and the method comprises the steps: 1, constructing a plane target track of a target flight task which comprises a starting point, an end point and n key points; 2, constructing a two-dimensional task flight profile between every two key points, and carrying out simulated path search on the two-dimensional task flight profiles to obtain a target two-dimensional track; step 3, repeating the step 2, obtaining a section of flight path between every two key points, and synthesizing each section of flight path to obtain a final unmanned aerial vehicle imitated flight path; the method comprises the following steps of: constructing a planar target track of a target flight task, constructing a two-dimensional task flight profile between every two key points, and carrying out simulated land path search on the two-dimensional task flight profiles to obtain a target two-dimensional track; and finally, the unmanned aerial vehicle imitated flight path meeting the preset flight path height adjustment constraint is obtained, the flight route is automatically planned according to the starting node and the target node, the flight path point does not need to be manually calibrated, and the flight route planning efficiency is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle terrain imitation flight routes, and in particular to a method for automatically planning unmanned aerial vehicle terrain imitation flight routes. Background Art

[0002] With the continuous development and maturity of UAV technology, the application of UAV in agriculture, surveying and mapping, security, transportation and other fields is becoming more and more extensive, which puts forward higher requirements on the accuracy and efficiency of path planning. UAV path planning usually adopts semi-automatic terrain-imitation flight path planning technology. This technology mainly includes two steps: manual calibration of track points and adjustment of route altitude. First, manually select several track points on the two-dimensional map to form a two-dimensional route that meets the mission requirements, and then calculate the altitude of each track point according to the mission requirements to determine the final UAV terrain-imitation flight track. However, due to the widespread application of UAVs and the complex working environment, coupled with the need for obstacle avoidance, the semi-automatic path planning method of manually calibrating track points is inefficient and difficult to meet the flight mission requirements.

[0003] Therefore, the research and application of automatic planning algorithms for UAV terrain-learning flight are of great significance. They can not only improve the efficiency and safety of UAV flight missions, but also promote the wider application and development of UAV technology in various fields. Summary of the invention

[0004] The present invention provides a method for automatically planning a terrain-imitating flight route for an unmanned aerial vehicle, aiming to solve the problems raised by the above-mentioned background technology.

[0005] The present invention is implemented in this way: a method for automatically planning a route for a drone's terrain-imitating flight comprises the following steps:

[0006] Step 1: construct a plane target track of a target flight mission, wherein the target flight mission includes a starting point, an end point, and n key points;

[0007] Step 2: construct a two-dimensional mission flight profile between every two key points, perform a terrain-simulating path search on the two-dimensional mission flight profile, and obtain a target two-dimensional track;

[0008] Step 3: Repeat step 2 to obtain a track between every two key points. Each track segment is synthesized to obtain the final UAV terrain-simulating flight track.

[0009] Specifically, the acquisition of the target two-dimensional trajectory in step 2 includes the following steps:

[0010] Step S1, obtaining the geospatial coordinates of the target area corresponding to the target flight mission, wherein the geospatial coordinates include terrain longitude, terrain latitude and altitude; and converting the geospatial coordinates to coordinate positions in a preset rectangular coordinate system;

[0011] Step S2, interpolate between two key points to obtain intermediate terrain information; and process the interpolation points to find the local maximum points therein, and regard the local maximum points as the peak vertices;

[0012] Step S3, adding the height of each local maximum point to the ground defense height h to obtain the simulated point, and adjusting the height of the simulated point according to the track constraint to obtain a feasible simulated point;

[0013] Step S4, repeating steps S2 and S3, and establishing an array of feasible simulation locations from the obtained feasible simulation locations;

[0014] Step S5, adding the starting point and the end point to the simulated location array, repeating step S4 until the last simulated location is the end point, then the points in the feasible simulated location array are the searched simulated location path points; and obtaining the target two-dimensional track.

[0015] Preferably, in step S1, the geographic spatial coordinates are converted to coordinate positions in a preset rectangular coordinate system, and the specific method is: starting from the starting point, a route is formed between every two key points, and the two endpoints of each route are respectively called the starting node and the ending node, and the coordinate position corresponding to the starting node is selected as the reference point, and the rectangular coordinate system is constructed based on the reference point, wherein the ordinate is the altitude and the abscissa is the distance from the point on this route to the starting point.

[0016] Preferably, in step S2, interpolation is performed between two key points to obtain intermediate terrain information, specifically, the latitude and longitude of the starting point and the end point are input, and a point is inserted every d meters from the starting point toward the end point to obtain the altitude information of the point. If the distance between the starting point and the end point is L, then an interpolation is performed between the starting point and the end point. interpolation points.

[0017] Preferably, in step S3, the height of the simulated point is adjusted according to the track constraint, including the preset track constraint including the pitch angle constraint and the dive angle constraint. Since the height of the key point is the terrain height plus the simulated flight height by default, a feasible ground defense route cannot be generated between two key points. If any simulated point between the starting point and the end point satisfies the following relationship with the starting point:

[0018]

[0019] Then it is impossible to generate a feasible defense path, where h i is the current point height, x i The horizontal distance from the current point to the starting point is the maximum pitch angle of the drone, h start is the starting height.

[0020] Preferably, the adjustment strategy in step S3 is to increase the height of the starting point by a certain step length. After the increase, all points between the starting point and the end point are judged. If there are still points that satisfy formula (1), the height of the starting point is continued to be increased until all simulated point heights do not satisfy formula (1).

[0021] Due to the adoption of the above scheme, the beneficial effects of the present invention are as follows: by constructing a planar target track of a target flight mission, wherein the target flight mission includes a starting point, an end point, and n key points; constructing a two-dimensional mission flight profile between every two key points, performing a terrain-simulating path search on the two-dimensional mission flight profile, and obtaining a target two-dimensional track; obtaining a track section between every two key points, and synthesizing each track section to obtain a final unmanned aerial vehicle terrain-simulating flight track; so as to obtain a unmanned aerial vehicle terrain-simulating flight track that ultimately meets a preset track height adjustment constraint, and automatically planning a flight route according to a starting node and a target node, without the need to manually calibrate track points, and effectively improving the efficiency of flight route planning. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the target flight mission of the present invention;

[0023] Figure 2 A schematic diagram of the coordinate position of the geographic space coordinates of the present invention converted to the coordinate position corresponding to the rectangular coordinate system;

[0024] Figure 3 It is a schematic diagram of interpolation points and local maximum points in the present invention;

[0025] Figure 4 It is a schematic diagram of the simulated location of the present invention;

[0026] Figure 5 A schematic diagram of the relationship between the pitch angle limitation in the present invention and the point that cannot be reached from the starting point;

[0027] Figure 6 It is a schematic diagram of the relationship between the dive angle limitation in the present invention and the point from which the dive cannot descend to the end point;

[0028] Figure 7 Schematic diagram of the relationship between simulated location i and simulated location j in the present invention;

[0029] Figure 8 This is a schematic diagram of the principle of the rising relationship and the falling relationship among point 1, point 2, and point 3 in the present invention;

[0030] Fig. 9 It is a schematic diagram of the longitude and latitude of the ground defense path in the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] The method for automatically planning a route for a UAV terrain-imitating flight comprises the following steps: constructing a plane trajectory of a target flight mission, wherein the target flight mission comprises a series of key points, such as Figure 1 As shown;

[0033] A two-dimensional mission flight profile is constructed between every two key points, and a terrain-simulating path search is performed on the two-dimensional mission flight profile to obtain a target two-dimensional track;

[0034] Specifically, a two-dimensional mission flight profile is constructed between every two key points, and a terrain-simulating path search is performed on the two-dimensional mission flight profile to obtain a target two-dimensional track;

[0035] Acquire the geospatial coordinates of the target area corresponding to the target flight mission, wherein the geospatial coordinates include terrain longitude, terrain latitude and altitude;

[0036] The geographic spatial coordinates are converted to coordinate positions in a preset rectangular coordinate system; starting from the starting point, each two key points form a route. The two endpoints of each route are called the starting node and the ending node. Figure 2 As shown, the coordinate position corresponding to the starting node is selected as the reference point, and the rectangular coordinate system is constructed based on the reference point. The ordinate is the altitude, and the abscissa is the distance from the point on this route to the starting point.

[0037] In step S2, interpolation is performed between two key points to obtain intermediate terrain information. Specifically, the latitude and longitude of the starting point and the end point are input, and a point is inserted every d meters from the starting point to the end point to obtain the altitude information of the point. If the distance between the starting point and the end point is L, then an interpolation is performed between the starting point and the end point. interpolation points;

[0038] Process the interpolation points to find the local maximum points among them, and regard the local maximum points as the peak vertices; find the local maximum points among these interpolation points through the local optimization algorithm, and regard these local maximum points as the peak vertices, such as Figure 3 As shown, the black points are interpolation points and the red points are local maximum points.

[0039] like Figure 4 , add the height of each local maximum point to the defense height h to get the simulated location.

[0040] In this application, the altitude of the simulated point is adjusted according to the trajectory constraints; the preset trajectory constraints include pitch angle constraints and dive angle constraints. Since the altitude of the key point defaults to the terrain height plus the simulated flight altitude, in some cases, it is impossible to generate a feasible ground defense route between two key points.

[0041] If any simulated point between the starting point and the end point (including the end point) and the starting point satisfies the following relationship:

[0042]

[0043] Then it is impossible to generate a feasible defense path, where h i is the current point height, x i The horizontal distance from the current point to the starting point is the maximum pitch angle of the drone, h start is the starting height.

[0044] like Figure 5 As shown in the figure, this situation means that the point cannot be reached from the starting point due to the pitch angle limit. In order to solve this problem, the starting point height needs to be adjusted;

[0045] The specific adjustment strategy is: increase the height of the starting point with a certain step length. In this embodiment, the height of the starting point is increased with a step length of 50 meters. After the increase, all points between the starting point and the end point (including the end point) are judged. If there are still points that satisfy formula (1), the height of the starting point is continued to be increased until all simulated point locations do not satisfy formula (1).

[0046] In this application, if any point between the starting point and the end point (including the end point) and the starting point satisfies the following relationship:

[0047]

[0048] where h i is the current point height, x end is the horizontal distance between the end point and the starting point, x i is the horizontal distance from the current point to the starting point, is the maximum dive angle of the UAV, h end is the end height.

[0049] Depend on Figure 6 It can be seen that this situation means that it is impossible to descend from this point to reach the end point due to the limit of the dive angle.

[0050] Similarly, in order to solve this problem, it is necessary to adjust the height of the end point by a certain step size. In this embodiment, the height of the end point is increased by a step size of 50 meters. After the increase, all points between the starting point (including the starting point) and the end point are judged. If there are still points that satisfy formula (2), the height of the end point is continued to be increased until all simulated point locations do not satisfy formula (2).

[0051] In this application, the simulated location is screened by calculating the intersection of rays, and the simulated path is searched; two rays are drawn through each simulated location, and the angle of the left ray is the maximum pitch angle of the aircraft. The angle of the ray to the right is the maximum dive angle of the aircraft. is called the rising ray at that point.

[0052] like Figure 7 As shown, up is the rising ray, l down is the descending ray, angle θ1 and the maximum pitch angle of the drone The angle θ2 is complementary to the maximum pitch angle of the drone. complementary angles;

[0053] Starting from the starting point, if the following relationship is satisfied between the simulated location i and the simulated location j:

[0054]

[0055] where h j is the height of point j, x j is the horizontal distance from point j to the starting point, and n is the total number of defense points between the two key points and their locations. If the first equation is satisfied between two simulated locations, the two points are said to satisfy the descending relationship. Similarly, if the second equation is satisfied between two simulated locations, the two points are said to satisfy the ascending relationship. If the two simulated locations satisfy both the ascending relationship and the descending relationship, it means that the descending ray of the earlier point of the two points intersects with the ascending ray of the later point.

[0056] like Figure 8 As shown in the figure, point 1 and the starting point do not satisfy the descending relationship, that is, it is impossible to reach point 1 even if the drone starts from the starting point and descends at the maximum dive angle. Points 2 and 3 satisfy both the ascending relationship and the descending relationship with the starting point. The descending ray of the starting point and the ascending rays of points 2 and 3 have two intersection points, namely intersection 1 and intersection 2. The height of intersection 1 is greater than that of intersection 2. The drone should start climbing in advance to ensure that it can reach point 3. If the drone reaches point 2 first and then starts climbing, the aircraft will not be able to reach point 3 because the angle between point 3 and point 2 is greater than the maximum pitch angle.

[0057] Put the starting point directly into the array of feasible simulated point locations. Starting from the starting point, calculate the intersection of the descending ray of the starting point and the ascending rays of all simulated point locations that satisfy both the ascending relationship and the descending relationship with the starting point. Calculate a set of ray intersections, find the simulated point location corresponding to the intersection with the highest altitude, and put this point into the array of feasible simulated point locations. After that, starting from this point, also calculate the intersection of the descending ray of this point and the ascending rays of all simulated point locations that satisfy both the ascending relationship and the descending relationship with this point. Find the simulated point location corresponding to the intersection with the highest altitude, which is the next feasible simulated point location, and similarly, put this point into the array of feasible simulated point locations. Repeat the operation until the feasible simulated point location is the end point. Then, the point in the array of feasible simulated point locations is the searched simulated path point.

[0058] The searched defense path is as follows: Fig. 9 As shown; after obtaining the terrain-simulating path points, the coordinates of these points are converted from the rectangular coordinate system back to the coordinates in the geographic coordinate system; the coordinate transformation is to convert the distance deviation into the actual longitude and latitude, and the conversion formula is as follows:

[0059]

[0060] tmp=(lat1+lat2) / 114.5916

[0061]

[0062] Among them, R e =6378165 is the radius of the earth, R lat is the radius corresponding to the current dimension, lon1 is the longitude of the starting key point, lat1 is the latitude of the starting key point, lon2 is the longitude of the final key point, lat2 is the latitude of the final key point, l is the distance from the terrain-like path point to the starting point, and ψ is the angle between the two key points.

[0063] A track is obtained between every two key points, and each track segment is synthesized to obtain the final UAV terrain-imitating flight track.

[0064] The above description of the embodiments is to facilitate the understanding and use of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the principles of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for automatically planning a route for an unmanned aerial vehicle's terrain-imitating flight, characterized in that: The steps include: Step 1: construct a plane target track of a target flight mission, wherein the target flight mission includes a starting point, an end point, and n key points; Step 2: construct a two-dimensional mission flight profile between every two key points, perform a terrain-simulating path search on the two-dimensional mission flight profile, and obtain a target two-dimensional track; Step 3: Repeat step 2 to obtain a track between every two key points. Each track segment is synthesized to obtain the final UAV terrain-simulating flight track. Specifically, the acquisition of the target two-dimensional trajectory in step 2 includes the following steps: Step S1, obtaining the geospatial coordinates of the target area corresponding to the target flight mission, wherein the geospatial coordinates include terrain longitude, terrain latitude and altitude; and converting the geospatial coordinates to coordinate positions in a preset rectangular coordinate system; Step S2, interpolate between two key points to obtain intermediate terrain information; and process the interpolation points to find the local maximum points therein, and regard the local maximum points as the peak vertices; Step S3, adding the height of each local maximum point to the ground defense height h to obtain the simulated point, and adjusting the height of the simulated point according to the track constraint to obtain a feasible simulated point; Step S4, repeating steps S2 and S3, and establishing an array of feasible simulation locations from the obtained feasible simulation locations; Step S5, adding the starting point and the end point to the simulated location array, repeating step S4 until the last simulated location is the end point, then the points in the feasible simulated location array are the searched simulated location path points; and obtaining the target two-dimensional track.

2. The method for automatically planning a route for an unmanned aerial vehicle's terrain-imitating flight according to claim 1, characterized in that: In step S1, the geographic spatial coordinates are converted to coordinate positions in a preset rectangular coordinate system. The specific method is: starting from the starting point, a route is formed between every two key points, and the two endpoints of each route are respectively called the starting node and the ending node. The coordinate position corresponding to the starting node is selected as the reference point, and the rectangular coordinate system is constructed based on the reference point, wherein the ordinate is the altitude and the abscissa is the distance between the point on this route and the starting point.

3. The method for automatically planning a route for an unmanned aerial vehicle's terrain-imitating flight according to claim 2, characterized in that: In step S2, interpolation is performed between two key points to obtain intermediate terrain information. Specifically, the latitude and longitude of the starting point and the end point are input, and a point is inserted every d meters from the starting point to the end point to obtain the altitude information of the point. If the distance between the starting point and the end point is L, then an interpolation is performed between the starting point and the end point. interpolation points.

4. The method for automatically planning a route for an unmanned aerial vehicle terrain-imitating flight according to claim 3, characterized in that: In step S3, the height of the simulated point is adjusted according to the track constraint, including the preset track constraint including the pitch angle constraint and the dive angle constraint. Since the height of the key point is the terrain height plus the simulated flight height by default, a feasible ground defense route cannot be generated between two key points. If any simulated point between the starting point and the end point satisfies the following relationship with the starting point: Then it is impossible to generate a feasible defense path, where h i is the current point height, x i The horizontal distance from the current point to the starting point is the maximum pitch angle of the drone, h start is the starting height.

5. The method for automatically planning a route for an unmanned aerial vehicle terrain-imitating flight according to claim 4, characterized in that: The adjustment strategy in step S3 is to increase the height of the starting point with a certain step length. After the increase, all points between the starting point and the end point are judged. If there are still points that satisfy formula (1), the height of the starting point is continued to be increased until all simulated point locations do not satisfy formula (1).

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