A collaborative trajectory planning method for multiple UAVs based on a two-layer rasterized map model

Abstract

The present application relates to the technical field of unmanned aerial vehicle (UAV) trajectory planning methods, and in particular to a multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model. First, the target to be inspected that needs to undergo power audit is determined, and then the first height and the second height are determined based on the target to be inspected, and then a double-layer rasterized map model is established based on the two heights; the first pilot UAV navigates on the top grid plane according to the determined pilot trajectory to achieve video sampling above the target to be inspected, and the second pilot UAV follows the first pilot UAV on the bottom grid plane to achieve video sampling below the target to be inspected. This method is simple and convenient, with few uncontrollable factors, good trajectory controllability, and strong practicality.

Description

Technical Field

[0001] The present application relates to the technical field of unmanned aerial vehicle (UAV) trajectory planning methods, and in particular to a multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model. Background Art

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

[0003] In the field of power auditing, drones can quickly cover large areas of power transmission lines and power facilities, and can capture real-time images required for auditing, and have become an important means to collect video data. However, for some overhead equipment such as overhead transmission lines, drones can only capture images above them. When judging the situation below, such as whether there is ice, it is also necessary to capture images below. If a drone is used, it often requires complex track measurement planning. The drone's track path has many uncontrollable factors and complex control logic. From another perspective, when conducting power audits through drones, the drone's track path is relatively simple. It only needs to capture images above or below the power facilities, and does not require too complicated track planning. If the existing track planning method is used, the cost is also relatively high.

[0004] In view of this, it is necessary to provide a multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model to solve the above technical problems. Summary of the invention

[0005] Based on this, in order to solve the above technical problems, the present application provides a multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model.

[0006] The technical solution adopted by this application to solve the problems existing in the prior art is:

[0007] This application proposes a multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model, comprising the following steps:

[0008] Step 1: determine the first height H1, take the horizontal plane where the first height H1 is located as the bottom grid plane, and establish a spatial rectangular coordinate system with the bottom grid plane as the XOY plane;

[0009] Wherein: the first height H1 is located below the lowest height of the shielding body of the first target to be inspected and the second target to be inspected from the ground and above the ground; the first target to be inspected refers to the target to be inspected at a certain height from the ground; the second target to be inspected refers to the target to be inspected with a shielding body and the shielding body is at a certain height from the ground;

[0010] Step 2: Determine the second height H2, take the horizontal plane where the second height H2 is located as the top grid plane, and establish a double-layer grid map model; obtain the target point set P of all targets to be inspected; determine the pilot track of the first pilot drone on the top grid plane according to the target point set P ;

[0011] Among them: Pilot track And the second height H2 satisfies the following conditions:

[0012] Will lead the way The top grid plane is vertically projected downward to the bottom grid plane to form the pilot projection track When the pilot projects the flight path satisfy:

[0013] The target point set P is the pilot projection track All points on the circle are the center, is a proper subset of the set of all circular regions of radius; ;

[0014] in: is the field of view of the vertically downward scanning camera on the first pilot drone; is the maximum reliable communication distance between the first pilot UAV and the second pilot UAV;

[0015] Step 3: Take the pilot track For the navigation path, a leader-follower model is constructed based on a double-layer rasterized map, with the first pilot UAV as the leader and the second pilot UAV as the follower.

[0016] Preferably, the method further includes step 4: constructing a track cost function of the second pilot UAV.

[0017] Preferably, the method for constructing a navigator-follower model based on a double-layer rasterized map with a first pilot drone as a navigator and a second pilot drone as a follower comprises the following steps:

[0018] Step 1:

[0019] Define the update expression of the motion state of the second pilot drone:

[0020]

[0021] in:

[0022] For the second pilot drone The speed of the moment;

[0023] For the second pilot drone Direction of travel at all times The angle of the axis;

[0024] The time it takes for the system mechanism to run one step; and Second pilot drone time The velocity component and Toward velocity component;

[0025] For the second pilot drone The coordinate point position at the time;

[0026] For the second pilot drone Time passes The next coordinate point position to be reached after time;

[0027] For the second pilot drone Moment and The distance between the positions of two points at a given moment;

[0028] Step 2: Construct a heterogeneous formation motion model of the second pilot UAV and the first pilot UAV:

[0029] Set the speed of the first pilot drone to a fixed value ;

[0030] The first pilot drone The coordinate point position formed by projecting the current position vertically downward onto the underlying grid plane;

[0031] The first pilot drone Time passes The arrival position after time is projected vertically downward to the coordinate point position formed by the underlying grid plane;

[0032] but:

[0033] The straight-line distance between the first pilot drone and the second pilot drone at this moment:

[0034]

[0035] and after The straight-line distance between the first pilot drone and the second pilot drone after time:

[0036]

[0037] Both meet:

[0038] < and < ;

[0039] Step 3: For the bottom grid plane of the double-layer rasterized map model, assign 1 and 0 variables to the obstacle area and non-obstacle area respectively, and construct the track control function of the second pilot drone:

[0040]

[0041] in:

[0042] Is the second pilot drone at the time The control input vector at time ;

[0043] It is the influence coefficient of the first pilot drone;

[0044] Indicates that the first pilot drone is at time The position vector is projected vertically downward from the current position to the coordinate point on the underlying grid plane;

[0045] Indicates that the second pilot drone is at time The position vector at time ;

[0046] Indicates that the first pilot drone is at time The position difference vector between the coordinate point vertically projected downward from the current position to the underlying grid plane and the second pilot UAV indicates the direction and distance the second pilot UAV needs to move toward the coordinate point projected to the underlying grid plane by the first pilot UAV;

[0047] is the influence coefficient of the obstacle area on the second pilot UAV, indicating the influence of the obstacle area on the second pilot UAV;

[0048] Indicates Obstacle area in time The position vector relative to the second pilot drone at time;

[0049] Represents the position difference vector between the obstacle area and the second pilot UAV;

[0050] Indicates the number of obstacle areas;

[0051] is the velocity attenuation coefficient;

[0052] Indicates that the second pilot drone is at time The velocity vector at time .

[0053] Preferably, the method for constructing a navigator-follower model based on a double-layer rasterized map with a first pilot drone as a navigator and a second pilot drone as a follower further includes:

[0054] Step 4: Conduct simulation experiments using the X-Plane UAV simulation platform to determine the best , and The value of .

[0055] Preferably, the track cost function Includes track length function , track smoothing function and track safety function ,in:

[0056]

[0057]

[0058]

[0059]

[0060] Where:

[0061] is the track length, For the Track nodes, is the total track node, It is a track segment With track segment The angle between is the distance between the track point and the nearest obstacle; is the weight of the track length, is the smoothness weight, is the weight of track safety.

[0062] Preferably, a vertically upward scanning camera is fixedly mounted on the second pilot drone.

[0063] Preferably, the first target to be inspected includes but is not limited to a distribution box, an insulator, an outdoor transformer, and a communication terminal installed at high altitude without any shielding above;

[0064] The second targets to be inspected include but are not limited to insulators with shielding bodies above them, remote signaling and telemetry equipment, and outdoor transformers.

[0065] Preferably, the first pilot drone and the second pilot drone are both equipped with a GPS positioning navigation system and a wireless communication module; the first pilot drone and the second pilot drone are both wirelessly connected to the background server; the first pilot drone and the second pilot drone are wirelessly connected.

[0066] Preferably, the grid size of the double-layer rasterized map model satisfies:

[0067]

[0068]

[0069] in:

[0070] and are the length and width of the grid respectively;

[0071] It is the maximum flight speed of the first pilot UAV and the second pilot UAV.

[0072] Preferably, any point in the target point set P to the pilot projection track The shortest distance on satisfy:

[0073] < .

[0074] Compared with the prior art, the beneficial effects of this application are:

[0075] 1. The double-layer grid map model is used to sort the UAV tracks into three-dimensional spatial coordinates, and then the track projection coordinates of the first pilot UAV are used to solve the two-dimensional plane coordinates. The calculation process is simple and accurate, the control logic is concise, and there are few uncontrollable factors.

[0076] 2. Taking into account the actual situation of power audit, the UAV flight path is planned to be inspected at two heights, the first height H1 and the second height H2, respectively, so that the audit results are comprehensive and accurate.

[0077] 3. The fixed coordinate points in the obstacle area are regarded as the follower of the second pilot UAV, and the first pilot UAV is projected from the top grid plane to the bottom grid plane, and brought into the improved leader-follower model, which simplifies the analysis process. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0079] Figure 1 This is a flowchart of the steps of the multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model of the present application. DETAILED DESCRIPTION

[0080] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0081] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0082] In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present disclosure, and do not specifically refer to any part or element in the present disclosure and should not be understood as limitations on the present disclosure.

[0083] refer to Figure 1 , which is a flowchart of the steps of the multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model of the present application. The multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model provided by the present application includes the following steps:

[0084] Step 1: determine the first height H1, take the horizontal plane where the first height H1 is located as the bottom grid plane, and establish a spatial rectangular coordinate system with the bottom grid plane as the XOY plane;

[0085] Wherein: the first height H1 is below the lowest height of the shielding bodies of the first target to be inspected and the second target to be inspected from the ground and above the ground; the first target to be inspected refers to the target to be inspected at a certain height from the ground; the second target to be inspected refers to the target to be inspected with a shielding body and the shielding body is at a certain height from the ground; the first target to be inspected includes but is not limited to the distribution box, insulator, outdoor transformer, and communication terminal installed at high altitude without shielding body above; the second target to be inspected includes but is not limited to the insulator, telesignaling and telemetry equipment, and outdoor transformer with shielding body above. A vertical upward scanning camera is fixedly installed on the second pilot drone. The first pilot drone and the second pilot drone are both equipped with GPS positioning navigation system and wireless communication module; the first pilot drone and the second pilot drone are both connected to the background server by wireless communication; the first pilot drone and the second pilot drone are connected by wireless communication.

[0086] Step 2: Determine the second height H2, take the horizontal plane where the second height H2 is located as the top grid plane, and establish a double-layer grid map model; obtain the target point set P of all targets to be inspected; determine the pilot track of the first pilot drone on the top grid plane according to the target point set P ;

[0087] Among them: Pilot track And the second height H2 satisfies the following conditions:

[0088] Will lead the way The top grid plane is vertically projected downward to the bottom grid plane to form the pilot projection track When the pilot projects the flight path satisfy:

[0089] The target point set P is the pilot projection track All points on the circle are the center, is a proper subset of the set of all circular regions of radius; In some embodiments, any point in the target point set P to the pilot projection track The shortest distance on satisfy:

[0090] < ;

[0091] in: is the field of view of the vertically downward scanning camera on the first pilot drone; is the maximum reliable communication distance between the first pilot UAV and the second pilot UAV;

[0092] Step 3: Take the pilot track For the navigation path, a leader-follower model is constructed based on a double-layer rasterized map, with the first pilot UAV as the leader and the second pilot UAV as the follower.

[0093] Step 4: Construct the trajectory cost function of the second pilot UAV.

[0094] The method for constructing a navigator-follower model based on a double-layer rasterized map with a first pilot drone as a navigator and a second pilot drone as a follower comprises the following steps:

[0095] Step 1:

[0096] Define the update expression of the motion state of the second pilot drone:

[0097]

[0098] in:

[0099] For the second pilot drone The speed of the moment;

[0100] For the second pilot drone Direction of travel at all times The angle of the axes;

[0101] The time it takes for the system mechanism to run one step; and The second pilot drone time The velocity component and Toward velocity component;

[0102] For the second pilot drone The coordinate point position at the time;

[0103] For the second pilot drone Time passes The next coordinate point position to be reached after time;

[0104] For the second pilot drone Moment and The distance between the positions of two points at a given moment;

[0105] Step 2: Construct a heterogeneous formation motion model of the second pilot UAV and the first pilot UAV:

[0106] Set the speed of the first pilot drone to a fixed value ;

[0107] The first pilot drone The coordinate point position formed by projecting the current position vertically downward onto the underlying grid plane;

[0108] The first pilot drone Time passes The arrival position after time is projected vertically downward to the coordinate point position formed by the underlying grid plane;

[0109] but:

[0110] The straight-line distance between the first pilot drone and the second pilot drone at this moment:

[0111]

[0112] and after The straight-line distance between the first pilot drone and the second pilot drone after time:

[0113]

[0114] Both meet:

[0115] < and < ;

[0116] In this step, the speed of the first pilot drone is set to a fixed value. This is because the first pilot UAV is located above each power facility and has a large movement space. In this application, it is set as the pilot aircraft of the second pilot UAV, which leads the second pilot UAV and its track is used as the pilot track of the second pilot UAV to adjust the track of the second pilot aircraft. and At the same time, less than , to ensure effective communication between the first pilot UAV and the second pilot UAV;

[0117] Step 3: For the bottom grid plane of the double-layer rasterized map model, assign 1 and 0 variables to the obstacle area and non-obstacle area respectively, and construct the second pilot drone track control function:

[0118]

[0119] in:

[0120] Is the second pilot drone at the time The second pilot UAV updates its position according to the position of the first pilot UAV;

[0121] It is the influence coefficient of the first pilot drone;

[0122] Indicates that the first pilot drone is at time The position vector is projected vertically downward from the current position to the coordinate point of the underlying grid plane;

[0123] Indicates that the second pilot drone is at time The position vector at time ;

[0124] Indicates that the first pilot drone is at time The position difference vector between the coordinate point vertically projected downward from the current position to the underlying grid plane and the second pilot UAV indicates the direction and distance the second pilot UAV needs to move toward the coordinate point projected to the underlying grid plane by the first pilot UAV;

[0125] is the influence coefficient of the obstacle area on the second pilot UAV, indicating the influence of the obstacle area on the second pilot UAV;

[0126] Indicates Obstacle area in time The position vector relative to the second pilot drone at time;

[0127] Represents the position difference vector between the obstacle area and the second pilot UAV;

[0128] Indicates the number of obstacle areas;

[0129] is the velocity attenuation coefficient;

[0130] Indicates that the second pilot drone is at time The velocity vector at time ;

[0131] In this step, the obstacle area is a fixed coordinate point, that is, in this application, the obstacle area of ​​each fixed coordinate point is regarded as a UAV at a fixed position and brought into the above-mentioned leader-follower model.

[0132] Step 4: Conduct simulation experiments using the X-Plane UAV simulation platform to determine the best , and The value of .

[0133] In some embodiments, the track cost function Includes track length function , track smoothing function and track safety function ,in:

[0134]

[0135]

[0136]

[0137]

[0138] Where:

[0139] is the track length, For the Track nodes, is the total track node, It is a track segment With track segment The angle between is the distance between the track point and the nearest obstacle; is the weight of the track length, is the smoothness weight, is the weight of track safety.

[0140] The track cost function is solved using a genetic algorithm. A genetic algorithm is an optimization algorithm based on biological evolution mechanisms, which is usually divided into steps such as generating an initial population, using genetic operators to perform genetic operations, calculating the fitness value of individuals, and iterating to obtain the optimal individual. In order to shorten the path length of the drone and improve the stability of the drone flight, in some embodiments, a deletion operator is added to the traditional genetic algorithm to delete redundant track points in the track. This is a common technical means used by those skilled in the art and will not be described in detail.

[0141] In some embodiments, the grid size of the two-layer rasterized map model satisfies:

[0142]

[0143]

[0144] in:

[0145] and are the length and width of the grid respectively;

[0146] It is the maximum flight speed of the first pilot UAV and the second pilot UAV.

[0147] The multi-UAV collaborative trajectory planning method of the present application based on a double-layer rasterized map model plans the UAV trajectory into two altitudes, a first altitude H1 and a second altitude H2, for inspection respectively. The control logic is simple and the audit result is accurate.

[0148] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0149] Although the above describes the specific implementation methods of the present application in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present application. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present application, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the present application.

Claims

1. A multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model, characterized in that: The following steps are involved: Step 1: determine the first height H1, take the horizontal plane where the first height H1 is located as the bottom grid plane, and establish a spatial rectangular coordinate system with the bottom grid plane as the XOY plane; Wherein: the first height H1 is located below the lowest height of the shielding body of the first target to be inspected and the second target to be inspected from the ground and above the ground; the first target to be inspected refers to the target to be inspected at a certain height from the ground; the second target to be inspected refers to the target to be inspected with a shielding body and the shielding body is at a certain height from the ground; Step 2: Determine the second height H2, take the horizontal plane where the second height H2 is located as the top grid plane, and establish a double-layer grid map model; obtain the target point set P of all targets to be inspected; determine the pilot track of the first pilot drone on the top grid plane according to the target point set P ; Among them: Pilot track And the second height H2 satisfies the following conditions: Will lead the way The top grid plane is vertically projected downward to the bottom grid plane to form the pilot projection track When the pilot projects the flight path satisfy: The target point set P is the pilot projection track All points on the circle are the center, is a proper subset of the set of all circular regions of radius; ; in: is the field of view of the vertically downward scanning camera on the first pilot drone; is the maximum reliable communication distance between the first pilot UAV and the second pilot UAV; Step 3: Take the pilot track For the navigation path, a leader-follower model is constructed based on a double-layer rasterized map, with the first pilot UAV as the leader and the second pilot UAV as the follower; The method for constructing a navigator-follower model based on a double-layer rasterized map with a first pilot drone as a navigator and a second pilot drone as a follower comprises the following steps: Step 1: Define the update expression of the motion state of the second pilot drone: in: For the second pilot drone The speed of the moment; For the second pilot drone Direction of travel at all times The angle of the axis; The time it takes for the system mechanism to run one step; and Second pilot drone time The velocity component and Toward velocity component; For the second pilot drone The coordinate point position at the time; For the second pilot drone Time passes The next coordinate point position to be reached after time; For the second pilot drone Moment and The distance between the positions of two points at a given moment; Step 2: Construct a heterogeneous formation motion model of the second pilot UAV and the first pilot UAV: Set the speed of the first pilot drone to a fixed value ; The first pilot drone The coordinate point position formed by projecting the current position vertically downward onto the underlying grid plane; The first pilot drone Time passes The arrival position after time is projected vertically downward to the coordinate point position formed by the underlying grid plane; but: The straight-line distance between the first pilot drone and the second pilot drone at this moment: and after The straight-line distance between the first pilot drone and the second pilot drone after time: Both meet: < and < ; Step 3: For the bottom grid plane of the double-layer rasterized map model, assign 1 and 0 variables to the obstacle area and non-obstacle area respectively, and construct the track control function of the second pilot drone: in: Is the second pilot drone at the time The control input vector at time ; It is the influence coefficient of the first pilot drone; Indicates that the first pilot drone is at time The position vector is projected vertically downward from the current position to the coordinate point on the underlying grid plane; Indicates that the second pilot drone is at time The position vector at time ; Indicates that the first pilot drone is at time The position difference vector between the coordinate point vertically projected downward from the current position to the underlying grid plane and the second pilot UAV indicates the direction and distance the second pilot UAV needs to move toward the coordinate point projected to the underlying grid plane by the first pilot UAV; is the influence coefficient of the obstacle area on the second pilot UAV, indicating the influence of the obstacle area on the second pilot UAV; Indicates Obstacle area in time The position vector relative to the second pilot drone at time; Represents the position difference vector between the obstacle area and the second pilot UAV; Indicates the number of obstacle areas; is the velocity attenuation coefficient; Indicates that the second pilot drone is at time The velocity vector at time .

2. The method for collaborative trajectory planning of multiple UAVs based on a double-layer rasterized map model according to claim 1 is characterized in that: It also includes step 4: constructing a track cost function for the second pilot UAV.

3. The method for collaborative trajectory planning of multiple UAVs based on a double-layer rasterized map model according to claim 1 is characterized in that: The method for constructing a navigator-follower model based on a double-layer rasterized map with a first pilot drone as a navigator and a second pilot drone as a follower also includes: Step 4: Conduct simulation experiments using the X-Plane UAV simulation platform to determine the best , and The value of .

4. The method for collaborative trajectory planning of multiple UAVs based on a double-layer rasterized map model according to claim 2 is characterized in that: The track cost function Includes track length function , track smoothing function and track safety function ,in: Where: is the track length, For the Track nodes, is the total track node, It is a track segment With track segment The angle between is the distance between the track point and the nearest obstacle; is the weight of the track length, is the smoothness weight, is the weight of track safety.

5. The method for collaborative trajectory planning of multiple UAVs based on a double-layer rasterized map model according to claim 1 is characterized in that: A vertical upward scanning camera is fixedly installed on the second pilot drone.

6. The method for collaborative trajectory planning of multiple UAVs based on a double-layer rasterized map model according to claim 1 is characterized in that: The first inspection targets include but are not limited to distribution boxes, insulators, outdoor transformers, and communication terminals installed at high altitudes without any shielding above; The second targets to be inspected include but are not limited to insulators with shielding bodies above them, remote signaling and telemetry equipment, and outdoor transformers.

7. The multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model according to claim 1 is characterized in that: The first pilot drone and the second pilot drone are both equipped with a GPS positioning navigation system and a wireless communication module; the first pilot drone and the second pilot drone are both wirelessly connected to the background server; the first pilot drone and the second pilot drone are wirelessly connected.

8. The multi-UAV collaborative trajectory planning method based on a double-layer rasterized map model according to claim 1 is characterized in that: The grid size of the double-layer rasterized map model satisfies: in: and are the length and width of the grid respectively; It is the maximum flight speed of the first pilot UAV and the second pilot UAV.

9. The method for collaborative trajectory planning of multiple UAVs based on a double-layer rasterized map model according to claim 1, characterized in that: Projection track from any point in the target point set P to the pilot The shortest distance on satisfy: ＜ 。

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