Vertical wind shear oriented linear flight method for maximizing solar energy acquisition of unmanned aerial vehicle in two-layer cloud weather

Abstract

The invention discloses a vertical wind shear oriented linear flight method for obtaining solar energy maximization by an unmanned aerial vehicle in two-layer cloud weather. The method comprises the following steps: establishing a two-layer cloud-hole model; based on a two-layer cloud hole model, establishing a condition that two cloud holes have an intersection point in a moving process; determining the intersection condition of the two cloud holes at the initial moment based on the intersection point existence condition, wherein the two cloud holes are externally tangent or do not intersect and do not contain each other, the two cloud holes intersect or the two cloud holes contain each other; and proposing an optimal linear flight path of the unmanned aerial vehicle based on a condition that the two cloud holes have an intersection point in a moving process and an intersection condition at an initial moment. The invention provides a vertical wind shear oriented linear flight method for maximizing solar energy acquisition of an unmanned aerial vehicle in two-layer cloud weather, and aims to provide an optimal linear flight scheme for the unmanned aerial vehicle to acquire solar energy in a researched two-layer cloud scene at complex positions and speeds of two dynamic cloud holes. The method physically accords with the scene of practical application and can be effectively applied to engineering practice.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) flight control, and in particular to a straight-line flight method for maximizing solar energy acquisition for a UAV facing vertical wind shear in two-layer cloud weather. Background Art

[0002] With the global emphasis on renewable energy and the continuous development of drone technology, solar charging technology provides a long-lasting and environmentally friendly energy solution for drones. High-efficiency solar panels installed on the drone's fuselage allow it to charge while flying in sufficient sunlight, significantly extending its flight time. This is particularly important for drones that need to perform long missions. The impact of cloud cover on drone solar charging is a complex and important background issue. Clouds, a common weather phenomenon in nature, have a significant impact on the utilization and conversion efficiency of solar energy. During the drone solar charging process, clouds block sunlight, reducing the light intensity received by the solar panels, thereby affecting charging efficiency. Furthermore, the changes and movement of clouds can cause fluctuations in light intensity, making the drone's energy input unstable during charging. Especially in thick cloud cover or overcast weather, the solar panels may not receive sufficient light, preventing the drone from effectively charging. This invention focuses on two-layer cloud weather scenarios, where vertical wind shear causes clouds at different altitudes to move at independent speeds and directions. However, since sunlight can only penetrate more directly through cloud holes when two cloud holes overlap, the key issue addressed by this invention is the flight direction, speed, and specific position of the drone to maximize solar charging. This in-depth theoretical analysis and application exploration of these issues aims to provide a unique and efficient solution. Summary of the Invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a straight-line flight method for maximizing solar energy acquisition for UAVs in two-layer cloud weather facing vertical wind shear. The purpose is to provide an optimal straight-line flight plan for UAVs to obtain more solar energy in a two-layer cloud scene under the complex position and speed changes of two dynamic cloud holes.

[0004] Technical Solution: To achieve the above objectives, the present invention provides a straight-line flight method for maximizing solar energy acquisition for a UAV facing vertical wind shear in two-layer cloud weather, comprising the following steps:

[0005] S1. Establish a two-layer cloud-hole model;

[0006] S2. Based on the two-layer cloud hole model, establish the condition for the intersection of two cloud holes during their movement;

[0007] S3. Determine the intersection of the two cloud holes at the initial moment, including whether the two cloud holes are circumscribed, do not intersect and do not contain each other, intersect, or contain each other;

[0008] S4. Based on the condition that there is an intersection point between two cloud holes during their movement and their intersection at the initial moment, a straight flight route is proposed for the UAV to maximize the solar energy acquisition.

[0009] Preferably, the two-layer cloud hole model is as follows: assuming that there are cloud holes 1 and cloud holes 2 in the first and second cloud layers respectively, a coordinate system is established with cloud hole 1 as the reference object, the position of the center of cloud hole 1 is the coordinate origin, and the initial position of cloud hole 2 in the coordinate system is obtained as (x2, y2), the flight speed of cloud hole 2 relative to cloud hole 1 is obtained as follows: In this coordinate system, the velocity direction of cloud hole 2 relative to cloud hole 1 is defined as the negative semi-axis direction of the X-axis, and the radii of cloud hole 1 and cloud hole 2 are r1 and r2, respectively.

[0010] Preferably, the cloud hole information required for establishing the cloud hole model is obtained by: obtaining a cloud layer image based on an image processing method, separating the high brightness area, and analyzing the characteristics of the area using color space;

[0011] Collect a large amount of labeled cloud images or sensor data to train machine models, and use the machine models to make predictions on real-time data.

[0012] Preferably, the condition for the two cloud holes to intersect during their movement is:

[0013] The time when cloud hole 1 and cloud hole 2 intersect each other satisfies the following formula:

[0014]

[0015] when When t≥0, it means that cloud hole 1 and cloud hole 2 may have an intersection during their movement. The solution with t≥0 is a valid intersection, and the solution with t<0 is an invalid intersection. According to the root-finding formula, the time when the distance between the centers of cloud hole 1 and cloud hole 2 is equal to r1+r2 is:

[0016]

[0017] and

[0018]

[0019] When Δ1<0, it means that cloud hole 1 and cloud hole 2 have no intersection during the movement process.

[0020] Preferably, the straight-line flight route for the drone to obtain maximum sunlight exposure is a point where the drone is relatively stationary within the range of cloud hole 1, and cloud hole 2 has a maximum chord length or line segment passing through this point, and the chord length covers this point after the initial moment of cloud hole 2, and the line segment has already covered this point at the initial moment of cloud hole 2.

[0021] Preferably, when cloud hole 1 and cloud hole 2 are circumscribed or do not intersect and do not contain each other at the initial moment,

[0022] At this time, if Δ1 ≥ 0 and t1 ≥ 0 and t2 ≥ 0 and y2 < -r1, the UAV is stationary at point (0, -r1) relative to cloud hole 1 in the coordinate system, and obtains a straight flight path with maximum sunlight exposure;

[0023] If Δ1 ≥ 0 and t1 ≥ 0 and t2 ≥ 0 and y2 > r1, the UAV is stationary at point (0, r1) relative to cloud hole 1 in the coordinate system, obtaining a straight flight path with maximum sunlight exposure;

[0024] If Δ1≥0 and t1≥0 and t2≥0 and -r1≤y2≤r1, then the UAV is stationary on the line segment relative to the cloud hole 1 in the coordinate system. Any point on the plane can obtain the straight flight path with maximum sunlight exposure, where the coordinates of point E and point F are and

[0025] Otherwise, it indicates that there is no overlapping coverage area between Cloud Cave 1 and Cloud Cave 2 during the flight, and there is no straight flight route where the UAV obtains maximum sunlight exposure.

[0026] Preferably, when cloud hole 1 and cloud hole 2 intersect at the initial moment, The circle defining Cloud Hole 2 intersects the circle defining Cloud Hole 1 at the "left point" and the "right point" at the initial moment, where the X-axis coordinate of the "left point" is not greater than the X-axis coordinate of the "right point".

[0027] At this time, if the "left point" is on the arc On the arc When y2≤-r1, the UAV is stationary at point (0,-r1) relative to cloud hole 1 in the coordinate system, and obtains a straight line flight path with maximum sunlight exposure. The coordinates of points B, C, and D are (0,r1), (r1,0), and (0,-r1), respectively.

[0028] If the "left point" is on the arc On the arc When y2 ≥ r1, the UAV is stationary at point (0, r1) relative to cloud hole 1 in the coordinate system, and obtains a straight flight path with maximum sunlight exposure;

[0029] If the "left point" is on the arc and -r1 ≤ y2 < 0 or 0 < y2 ≤ r1, then the drone is stationary relative to cloud hole 1 in the coordinate system at any point on the shorter of the line segments and to obtain a straight flight route with maximum sunlight exposure, where the coordinates of points E and F are and [[ID=1…]]G is the left intersection point of the straight line parallel to the X-axis where the center of cloud hole 2 is located and the circle where cloud hole 2 is located, with coordinates (x2 - r2, y2);

[0030] If y2 = 0 and x

[0039] , , , ,

[0038] ≥ x E then the drone is stationary relative to cloud hole 1 in the coordinate system at any point on the line segment [[ID=2…]] to obtain a straight flight route with maximum sunlight exposure, where x G = x2 - r2 and are the X-axis coordinates of point G and point E respectively;

[0031] If the "left point" is on the arc and y2 ≤ -r1 and x2 ≥ 0, then the drone is stationary relative to cloud hole 1 in the coordinate system at the "left point" to obtain a straight flight route with maximum sunlight exposure, and the coordinates of point A are (-r1, 0);

[0032] If the "left point" is on the arc and y2 ≥ r1 and x2 ≥ 0, then the drone is stationary relative to cloud hole 1 in the coordinate system at the "left point" to obtain a straight flight route with maximum sunlight exposure;

[0033] If the "left point" is on the arc and -r1 ≤ y2 < 0 or 0 < y2 ≤ r1 and x2 ≥ 0, then the drone is stationary relative to cloud hole 1 in the coordinate system at the "left point" to obtain a straight flight route with maximum sunlight exposure;

[0034] Otherwise, the drone is stationary relative to cloud hole 1 in the coordinate system at the outer tangent point where cloud hole 2 and cloud hole 1 finally separate to obtain a straight flight route with maximum sunlight exposure.

[0035] Preferably, the coordinates of the "left point" are:

[0036] <00001…]]<00…]]

[0037] and

[0038]

[0039] where, ​​

[0040] Preferably, when the cloud hole 1 and the cloud hole 2 contain each other at the initial moment,

[0041] At this time, if r2 < r1, the drone is stationary relative to the cloud hole 1 in the coordinate system at any point on the line segment and obtains the straight-line flight route with the maximum sunlight irradiation. The coordinates of point E are The coordinates of G are (x2 - r2, y2);

[0042] If r2 ≥ r1, the drone is stationary relative to the cloud hole 1 in the coordinate system at the outer tangent point where the cloud hole 2 and the cloud hole 1 finally separate, and obtains the straight-line flight route with the maximum sunlight irradiation.

[0043] Preferably, the outer tangent point where the cloud hole 2 and the cloud hole 1 finally separate is obtained by simultaneously solving the circle equation of the cloud hole 2 and the circle equation of the cloud hole 1 (x) 2 +(y) 2 =(r1) 2 at the moment to obtain the coordinates of the point where the cloud hole ② and the cloud hole ① are finally externally tangent.

[0044] Beneficial effects: The present invention has the following advantages: Based on the complex positions and velocities of two dynamic cloud holes in a two-layer cloud scenario, the present invention gives an optimal straight-line flight plan for a drone to obtain solar energy, which physically conforms to the realistic application scenario and can be effectively applied to engineering practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 (a) - (d) are schematic diagrams of the scenarios where the cloud hole 1 and the cloud hole 2 are externally tangent, do not intersect, and do not contain each other;

[0046] Figure 2 (a) - (j) are schematic diagrams of the scenarios where the cloud hole 1 and the cloud hole 2 intersect;

[0047] Figure 3 (a) - (b) are schematic diagrams of the scenarios where the cloud hole 1 and the cloud hole 2 contain each other;

[0048] Figure 4 is the scenario diagram of the straight-line flight method for maximizing the solar energy acquisition of a drone facing vertical wind shear in a two-layer cloud weather. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The technical solutions of the present invention will be described in detail below in conjunction with the embodiments and the drawings.

[0050] Multi-layer cloud weather is usually characterized by the simultaneous presence of multiple cloud layers at different heights in the atmosphere. The present invention studies the more common two-layer cloud weather in multi-layer cloud weather scenarios.

[0051] In most cases, cloud holes can be approximated as circles. If the cloud holes are of other shapes, the longest flight time within the area can be used as the flight route of the drone for planning, thereby obtaining the maximum solar energy. Since irregular cloud hole areas cannot be established using precise mathematical models, and in altocumulus or cirrostratus clouds, supercooled water droplets evaporate or ice crystals fall, forming circular or elliptical cloud holes, the present invention assumes that the cloud hole areas of each cloud layer are circular. Vertical wind shear caused by factors such as pressure gradient force, Coriolis force, ground friction, and thermal effects causes wind speed or wind direction to change in the vertical direction. Therefore, for the two-layer cloud weather studied, different cloud layers have different wind speeds and directions.

[0052] Drones can fly in a straight line or dynamically adjust their direction and speed. Straight-line flight requires no frequent adjustments to direction or altitude, maintains a stable flight attitude, and is simple to control. Dynamically adjusted flight involves dynamic adjustment of direction and speed, exhibits significant flight attitude changes, and is complex to control. Based on the above analysis, it can be seen that when a drone flies in a straight line, the power consumption of its motor and control system is relatively stable due to its fixed flight path. Furthermore, the drone can maintain an optimal aerodynamic attitude and reduce drag. Therefore, in terms of energy consumption, straight-line flight is more energy-efficient than dynamic adjustment flight. Therefore, in this invention, it is assumed that the drone adopts the common straight-line flight method.

[0053] Although different cloud layers have their own cloud holes, due to the inconsistency of the movement and speed directions of each cloud layer, the cloud hole of the lower cloud layer may be blocked by the upper cloud layer, or the cloud hole of the upper cloud layer may be blocked by the lower cloud layer from direct sunlight, thus affecting the solar energy conversion efficiency of the UAV. Figure 4 Therefore, it is necessary to consider the flight direction, speed, and position of the drone in the air to obtain the maximum solar charging. Specifically, the following are included:

[0054] 1. Obtain the two-layer cloud hole area information and establish a two-layer cloud hole model.

[0055] Assume that there are cloud holes 1 and cloud holes 2 in the first and second cloud layers respectively. Establish a coordinate system with cloud hole 1 as the reference object, and the position of the center of cloud hole 1 as the coordinate origin. The initial position of cloud hole 2 in the coordinate system is obtained as (x2, y2), and the flight speed of cloud hole 2 relative to cloud hole 1 is In this coordinate system, the velocity direction of cloud hole 2 relative to cloud hole 1 is defined as the negative semi-axis direction of the X-axis, and the radii of cloud hole 1 and cloud hole 2 are r1 and r2, respectively.

[0056] Cloud cave area information can be obtained in the following ways:

[0057] Image processing methods: Using cameras or satellite imagery to capture images of the ground or sky, the cloud holes in each cloud layer are distinguished by analyzing the brightness, color, and texture characteristics of the images. This involves acquiring image data; using image segmentation algorithms (such as threshold segmentation and edge detection) to isolate high-brightness areas; and analyzing the characteristics of areas directly exposed to sunlight using color space (such as HSV).

[0058] Machine learning-based detection methods use historical data and machine learning algorithms (such as convolutional neural networks (CNNs)) to train models and identify areas of direct sunlight. This involves collecting large amounts of labeled images or sensor data, training machine learning models, and using the models to make predictions based on real-time data.

[0059] 2. Based on the two-layer cloud hole model, the conditions for the existence of intersections between the two-layer cloud holes during movement are established.

[0060] In the coordinate system, the coordinates of the center of cloud hole 2 change with time t as follows:

[0061]

[0062] in, is the relative velocity of cloud hole 2 with respect to cloud hole 1 as a reference.

[0063] The distance between the centers of the two cloud holes is:

[0064]

[0065] And when d(t) = r1 + r2, cloud hole 1 and cloud hole 2 are circumscribed, and the circumscribed time satisfies the following formula:

[0066]

[0067] like This indicates that the two cloud holes are relatively stationary. At this time, if the two cloud holes have an overlapping area at the initial moment, the drone can obtain a straight-line flight path with maximum sunlight exposure by being stationary relative to cloud hole 1 at any point within the overlapping coverage area (the straight-line flight at this time is the actual flight state relative to the earth); if the two cloud holes have no overlapping area at the initial moment, the drone cannot obtain solar charging.

[0068] like The above is a quadratic equation about time t, so according to the root-finding formula we can know that:

[0069] when When , it means that cloud hole 1 and cloud hole 2 may have an intersection during their movement (the solution with t ≥ 0 is a valid intersection, and the solution with t < 0 is an invalid intersection). According to the root-finding formula, the time when the distance between the centers of cloud hole 1 and cloud hole 2 is equal to r1 + r2 is:

[0070]

[0071] and

[0072]

[0073] When Δ1<0, it means that cloud hole 1 and cloud hole 2 have no intersection during the movement process.

[0074] For the convenience of description, the four points (-r1,0), (0,r1), (r1,0) and (0,-r1) in the coordinate system are named point A, point B, point C and point D.

[0075] At the same time, the straight-line flight path for the UAV to obtain maximum sunlight exposure should be the point where the UAV is relatively stationary within the range of cloud hole 1, and cloud hole 2 has the maximum chord length (cloud hole 2 covers this point after the initial moment) or line segment (cloud hole 2 has already covered this point at the initial moment) passing through this point.

[0076] 3. Based on the condition that two cloud holes have an intersection during movement, the intersection of the two cloud holes is determined, including: the two cloud holes are circumscribed or do not intersect and do not contain each other, the two cloud holes intersect or the two cloud holes contain each other, and a straight-line flight plan for the UAV is given.

[0077] 1. Cloud hole 1 and cloud hole 2 are initially circumscribed or do not intersect and do not contain each other. In the coordinate system, they have

[0078] (1) If Δ1≥0 and t1≥0 and t2≥0 and y2<-r1, then Figure 1 As shown in (a), the UAV can obtain a straight flight path with maximum sunlight exposure when it is stationary at point D(0, -r1) relative to cloud hole 1 in the coordinate system (the straight flight at this time is the actual flight state relative to the earth);

[0079] (2) If Δ1≥0 and t1≥0 and t2≥0 and y2>r1, then Figure 1 As shown in (b), the UAV can obtain a straight flight path with maximum sunlight exposure when it is stationary at point B(0, r1) relative to cloud hole 1 in the coordinate system (the straight flight at this time is the actual flight state relative to the earth);

[0080] (3) If Δ1≥0 and t1≥0 and t2≥0 and -r1≤y2≤r1, then Figure 1(c) As shown. For this situation, during the movement of cloud hole 2 relative to cloud hole 1, there are two points where the distance between the centers of cloud hole 1 and cloud hole 2 is equal to r1 + r2. Define the straight line parallel to the X-axis where the center of cloud hole 2 is located, which intersects the circle of cloud hole 1 at point E (left side) and point F (right side). Then, for any point on the line segment where the drone is stationary relative to cloud hole 1 in the coordinate system, it can obtain the straight-line flight route with the maximum sunlight exposure (at this time, the straight-line flight is the actual flight state relative to the ground). The coordinates of point E and point F are and

[0081] (4) If the conditions in (1) to (3) above are not satisfied, as Figure 1 (d) shown, it indicates that there is no overlapping coverage area between cloud hole 1 and cloud hole 2 during flight. Therefore, there is no straight-line flight route for the drone to charge with solar energy.

[0082] 2. Cloud hole 1 and cloud hole 2 intersect at the initial moment, then there is For the convenience of explanation, for this scenario, define that the circle of cloud hole 2 intersects the circle of cloud hole 1 at the "left point" and the "right point" at the initial moment, where the X-axis coordinate of the "left point" is not greater than the X-axis coordinate of the "right point".

[0083] (1) If the "left point" is on the arc (all arcs in this invention refer to the circumference with the position of cloud hole 1 as the center and the coverage range as the radius) and the "right point" is on the arc and y2 ≤ -r1, as Figure 2 (a) shown, then the drone can obtain the straight-line flight route with the maximum sunlight exposure when it is stationary relative to cloud hole 1 at point D(0, -r1) in the coordinate system (at this time, the straight-line flight is the actual flight state relative to the ground);

[0084] (2) If the "left point" is on the arc and the "right point" is on the arc and y2 ≥ r1, as Figure 2 (b) shown, then the drone can obtain the straight-line flight route with the maximum sunlight exposure when it is stationary relative to cloud hole 1 at point B(0, r1) in the coordinate system (at this time, the straight-line flight is the actual flight state relative to the ground);

[0085] (3) If the "left point" is on the arc and -r1 ≤ y2 < 0 or 0 < y2 ≤ r1, as Figure 2 (c) and Figure 2 (d) shown, then the drone is stationary relative to cloud hole 1 at the line segment and Any point on the shorter line segment can obtain the straight flight route with maximum sunlight exposure (the straight flight at this time is the actual flight state relative to the earth), where the coordinates of point E and point F are and Point G is defined as the intersection of the line parallel to the X-axis and the left side of the circle of Cloud Hole 2, where the center of Cloud Hole 2 is located. The coordinates are (x2-r2,y2);

[0086] (4) If y2=0 and x G ≥x E When (where x G =x2-r2 and are the X-axis coordinates of point G and point E respectively), such as Figure 2 As shown in (e), the UAV is stationary on the line segment relative to the cloud hole 1 in the coordinate system. Any point on the can obtain the straight line flight route with maximum sunlight exposure (the straight line flight at this time is the actual flight state relative to the earth), where the coordinates of point E are The G coordinate is (x2-r2,y2);

[0087] (5) If the "left point" is on the arc When y2≤-r1 and x2≥0, Figure 2 As shown in (f), the UAV can obtain a straight flight path with maximum sunlight exposure by being stationary at the "left point" relative to the cloud hole 1 in the coordinate system (the straight flight at this time is the actual flight state relative to the earth);

[0088] In the coordinate system with cloud hole 1 as the reference object at the initial moment, the circle equation of cloud hole 2 is

[0089] (x-x2) 2 +(y-y2) 2 =(r2) 2

[0090] The circle equation of cloud hole 1 is

[0091] (x) 2 +(y) 2 =(r1) 2

[0092] Combining the above two circle equations about cloud hole 1 and cloud hole 2 at the initial time and solving them, we can obtain the coordinates of the left side points of cloud hole 2 and cloud hole 1 at the initial time as follows:

[0093]

[0094] and

[0095]

[0096] in,

[0097] (6) If the "left point" is on the circular arc and y2 ≥ r1 and x2 ≥ 0, as shown in Figure 2 (g), then the drone is stationary at the "left point" relative to Cloud Hole 1 in the coordinate system and can obtain the straight-line flight route with the maximum sunlight exposure (the straight-line flight at this time is the actual flight state relative to the ground);

[0098] (7) If the "left point" is on the circular arc and -r1 ≤ y2 < 0 or 0 < y2 ≤ r1 and x2 ≥ 0, as shown in Figure 2 (h), then the drone is stationary at the "left point" relative to Cloud Hole 1 in the coordinate system and can obtain the straight-line flight route with the maximum sunlight exposure (the straight-line flight at this time is the actual flight state relative to the ground);

[0099] (8) If the conditions in (1) to (7) above are not satisfied, as shown in Figure 2 (i) and Figure 2 (j), that is, at the initial moment, the outer tangent point where Cloud Hole 2 and Cloud Hole 1 finally separate is within the direct sunlight area, then the drone is stationary at the outer tangent point where Cloud Hole 2 and Cloud Hole 1 finally separate relative to Cloud Hole 1 in the coordinate system and can obtain the straight-line flight route with the maximum sunlight exposure.

[0100] The position of the center of Cloud Hole 2 at time t2 is

[0101]

[0102] At this time, the circular equation of Cloud Hole 2 is

[0103]

[0104] The circular equation of Cloud Hole 1 is

[0105] (x) 2 +(y) 2 =(r1) 2

[0106] Combining the above two circular equations of Cloud Hole 1 and Cloud Hole 2 at the moment and solving them can obtain the coordinates of the point where Cloud Hole 2 and Cloud Hole 1 are finally externally tangent.

[0107] 3. If Cloud Hole 1 and Cloud Hole 2 contain each other at the initial moment, then

[0108] (1) If r2 < r1, as shown in Figure 3 (a), then the drone is stationary at the line segment relative to Cloud Hole 1 in the coordinate system Any point on the can obtain the straight line flight route with maximum sunlight exposure (the straight line flight at this time is the actual flight state relative to the earth), where the coordinates of point E are The G coordinate is (x2-r2,y2);

[0109] (2) If r2 ≥ r1, Figure 3 As shown in (b), the UAV can obtain a straight flight path with maximum sunlight exposure when it is stationary at the point where Cloud Hole 2 and Cloud Hole 1 are finally tangent to each other in the coordinate system relative to Cloud Hole 1 (the straight flight at this time is the actual flight state relative to the earth). The coordinates of the tangent point are obtained by the method given in (8) in 2. This is because the UAV is initially located within the coverage of Cloud Hole 1, so it is already in the direct sunlight area at the initial moment. As Cloud Hole 2 moves, the overlapping coverage area decreases. Therefore, when the tangent point where the two circles of Cloud Hole 1 and Cloud Hole 2 are finally separated is the last direct sunlight area, so the UAV can obtain the maximum solar charging by choosing this point.

Claims

1. A straight-line flight method for maximizing solar energy acquisition for a UAV facing vertical wind shear in two-layer cloud weather, characterized by: The steps include: S1. Establish a two-layer cloud-hole model; S2. Based on the two-layer cloud hole model, establish the condition for the intersection of two cloud holes during their movement; S3. Determine the intersection of the two cloud holes at the initial moment, including whether the two cloud holes are circumscribed, do not intersect and do not contain each other, intersect, or contain each other; S4. Based on the condition that there is an intersection point between two cloud holes during their movement and their intersection at the initial moment, a straight flight route is proposed for the UAV to maximize the solar energy acquisition.

2. The straight-line flight method according to claim 1, characterized in that: The two-layer cloud hole model is as follows: Assume that there are cloud holes 1 and cloud holes 2 in the first and second cloud layers respectively, establish a coordinate system with cloud hole 1 as the reference object, and the position of the center of cloud hole 1 as the coordinate origin. The initial position of cloud hole 2 in the coordinate system is obtained as (x2, y2), and the flight speed of cloud hole 2 relative to cloud hole 1 is In this coordinate system, the velocity direction of cloud hole 2 relative to cloud hole 1 is defined as the negative semi-axis direction of the X-axis, and the radii of cloud hole 1 and cloud hole 2 are r1 and r2, respectively.

3. The straight-line flight method according to claim 2, characterized in that: The cloud hole information required to establish the cloud hole model is obtained in the following ways: cloud layer images are obtained based on image processing methods, and high brightness areas are separated, and the characteristics of the areas are analyzed using color space; Collect a large amount of labeled cloud images or sensor data to train machine models, and use the machine models to make predictions on real-time data.

4. The straight-line flight method according to claim 2, characterized in that: The condition for the two cloud holes to intersect during their movement is: The time when cloud hole 1 and cloud hole 2 intersect each other satisfies the following formula: when When t≥0, it means that cloud hole 1 and cloud hole 2 may have an intersection during their movement. The solution with t≥0 is a valid intersection, and the solution with t<0 is an invalid intersection. According to the root-finding formula, the time when the distance between the centers of cloud hole 1 and cloud hole 2 is equal to r1+r2 is: and When Δ1<0, it means that cloud hole 1 and cloud hole 2 have no intersection during the movement process.

5. The straight-line flight method according to claim 2, characterized in that: The straight-line flight path where the drone receives maximum sunlight exposure is the point where the drone is relatively stationary within the range of cloud hole 1, and cloud hole 2 has the maximum chord length or line segment passing through this point. The chord length covers this point after the initial moment of cloud hole 2, and the line segment has already covered this point at the initial moment of cloud hole 2.

6. The straight-line flight method according to claim 4, characterized in that: When cloud hole 1 and cloud hole 2 are circumscribed or do not intersect and do not contain each other at the initial moment, At this time, if Δ1 ≥ 0 and t1 ≥ 0 and t2 ≥ 0 and y2 < -r1, the UAV is stationary at point (0, -r1) relative to cloud hole 1 in the coordinate system, and obtains a straight flight path with maximum sunlight exposure; If Δ1 ≥ 0 and t1 ≥ 0 and t2 ≥ 0 and y2 > r1, the UAV is stationary at point (0, r1) relative to cloud hole 1 in the coordinate system, obtaining a straight flight path with maximum sunlight exposure; If Δ1≥0 and t1≥0 and t2≥0 and -r1≤y2≤r1, then the UAV is stationary on the line segment relative to the cloud hole 1 in the coordinate system. Any point on the plane can obtain the straight flight path with maximum sunlight exposure, where the coordinates of point E and point F are and Otherwise, it indicates that there is no overlapping coverage area between Cloud Cave 1 and Cloud Cave 2 during the flight, and there is no straight flight route where the UAV obtains maximum sunlight exposure.

7. The straight-line flight method according to claim 4, characterized in that: When Cloud Cave 1 and Cloud Cave 2 intersect at the initial moment, The circle defining Cloud Hole 2 intersects the circle defining Cloud Hole 1 at the "left point" and the "right point" at the initial moment, where the X-axis coordinate of the "left point" is not greater than the X-axis coordinate of the "right point". At this time, if the "left point" is on the arc On the arc When y2≤-r1, the UAV is stationary at point (0,-r1) relative to cloud hole 1 in the coordinate system, and obtains a straight line flight path with maximum sunlight exposure. The coordinates of points B, C, and D are (0,r1), (r1,0), and (0,-r1), respectively. If the "left point" is on the arc On the arc When y2 ≥ r1, the UAV is stationary at point (0, r1) relative to cloud hole 1 in the coordinate system, and obtains a straight flight path with maximum sunlight exposure; If the "left point" is on the arc and -r1 ≤ y2 < 0 or 0 < y2 ≤ r1, then the drone is stationary relative to Cloud Hole 1 in the coordinate system at any point on the shorter of the line segments and and obtains the straight-line flight route with the maximum sunlight exposure. The coordinates of points E and F are and G is the left intersection point of the line parallel to the X-axis where the center of Cloud Hole 2 is located and the circle where Cloud Hole 2 is located, with coordinates (x2 - r2, y2); If y2=0 and x G ≥x E When , the UAV is stationary on the line segment relative to the cloud hole 1 in the coordinate system For any point on the G =x2-r2 and are the X-axis coordinates of point G and point E respectively; If the "left point" is on the arc When y2≤-r1 and x2≥0, the UAV is stationary at the "left point" relative to cloud hole 1 in the coordinate system, and obtains a straight flight path with maximum sunlight exposure. The coordinates of point A are (-r1,0); If the "left point" is on the arc When y2≥r1 and x2≥0, the UAV is stationary at the "left point" relative to the cloud hole 1 in the coordinate system, and obtains a straight flight path with maximum sunlight exposure; If the "left point" is on the arc and -r1 ≤ y2 < 0 or 0 < y2 ≤ r1 and x2 ≥ 0, then the drone is stationary at the "left point" relative to the cloud hole 1 in the coordinate system, and obtains a straight flight route with the maximum sunlight exposure; Otherwise, the UAV is stationary at the external tangent point where cloud hole 2 and cloud hole 1 are last separated in the coordinate system relative to cloud hole 1, and obtains a straight flight path with maximum sunlight exposure.

8. The straight-line flight method according to claim 7, characterized in that: The coordinates of the "left point" are: and in, 9. The straight-line flight method according to claim 7, characterized in that: When Cloud Hole 1 and Cloud Hole 2 contain each other at the initial moment, At this time, if r2 < r1, the drone is stationary relative to the cloud hole 1 at any point on the line segment in the coordinate system, and obtains the straight-line flight route with the maximum sunlight exposure. The coordinates of point E are The coordinates of G are (x2 - r2, y2); If r2 ≥ r1, the UAV will be stationary at the external tangent point where cloud hole 2 and cloud hole 1 are last separated in the coordinate system relative to cloud hole 1, and obtain a straight flight path with maximum sunlight exposure.

10. The straight-line flight method according to claim 9, characterized in that: The coordinates of the external tangent point where the cloud hole 2 and the cloud hole 1 are finally separated are obtained by the circle equation of the cloud hole 2. and the circle equation of Yundong 1 (x) 2 +(y) 2 =(r1) 2 At the moment Perform joint solution to obtain .

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