A method for maintaining energy consistency of drone clusters

Abstract

The present invention discloses a method for maintaining energy consistency of each member of a drone cluster during long-distance flight. The present invention considers the influence of vortex surfing phenomenon on member energy consumption during formation flight of drone clusters, and plans the expected position of member aircraft and the priority of each position on a preset cluster formation. The drone cluster members keep updating the energy information of other members during flight and calculate the average remaining energy of cluster members. A low energy difference percentage threshold is set. When the difference between the remaining energy of a member aircraft and the remaining energy of the average member of the cluster exceeds the threshold, a position exchange request message is issued, and the remaining members with remaining energy higher than the average remaining energy of the cluster members and feedback status information are requested. The publisher of the information is requested to evaluate the feedback information, and the winner is selected based on the distance and remaining power of the feedback. Position exchange transfer trajectories of different heights are set. If there are multiple aircrafts transferring positions at the same time, the transfer trajectory height is configured based on the priority of each aircraft. After the publisher of the request information and the feedbacker confirm each other, they exchange positions to each other along the transfer trajectory.

Description

Technical Field

[0001] The present invention relates to the technical field of drone cluster control, and more specifically, to a method for maintaining energy consistency of a drone cluster. Background Art

[0002] With the development of drone technology, multi-drone collaboration has become a hot frontier field of drone system control, and the formation flight of drone clusters is one of the key modes of drone collaboration. Through formation flight, drones can obtain a larger visual area, increase aerodynamic efficiency and the success rate of strike / search missions, and improve system robustness. When drones fly in formation to a distant destination to perform tasks, due to the differences in performance parameters of different member aircraft and the different resistance and disturbances encountered during flight, the energy consumption between member aircraft will be greatly different during long-distance flight. If the remaining energy of a single member aircraft is too low, its mission cannot be performed normally, which in turn affects the overall function of the drone cluster system.

[0003] Based on the research results of bionics, when birds fly in formation, the birds behind are affected by the upwash effect of the vortex generated by the birds in front, and their physical energy consumption is significantly reduced. When birds migrate over long distances, they can effectively increase the range of the overall movement of the formation by changing the formation and replacing the head bird. Further research shows that aircraft formations will also produce similar effects when flying. Wind tunnel tests show that using a 3% scaled-down Boeing 747 as the lead aircraft and an ordinary fighter model as the wingman, the lift-to-drag ratio of the wingman is measured to increase by 50%. Formation flight experiments of tailless delta-wing aircraft conducted in the full-scale wind tunnel of the Langley Research Center have shown that the wingman can achieve a maximum reduction of 25% in induced drag. The results of the "vortex surfing" flight test of the C-17 transport aircraft completed by the US Air Force at Edwards Air Force Base in 2012 show that formation flight can save a lot of fuel and costs.

[0004] Through the study of the relevant mechanism of reducing energy consumption through formation flight, it is known that the energy consumption of the members of the UAV cluster formation is closely related to their relative position in the formation. The distance between the two wingtip vortices generated by the front member on the wing is approximately d = πb / 4, where b is the wingspan distance. The stable extension range of the vortex to the rear of the wing is generally within the near-field tail vortex extension zone within 10 times the wingspan. In order to better utilize the wingtip vortex of the front aircraft, the rear member needs to maintain an 11% overlap with the wing of the front aircraft in the lateral direction. Using this phenomenon, the relative positions of the member aircraft can be dynamically adjusted based on the residual energy distribution of the member aircraft, thereby achieving energy consistency of the UAV cluster. Summary of the invention

[0005] When a drone swarm flies in formation to a distant destination to perform a mission, the energy consumption of different members may differ due to differences in performance parameters of different member aircraft and different resistance and disturbances encountered during flight. The present invention proposes a method for maintaining the energy consistency of a drone swarm by utilizing the wingtip vortex of the leading aircraft and dynamically adjusting the relative positions of the member aircraft. The specific technical solution of the method is as follows:

[0006] S1: Based on the distance between the wing tip vortex centers and the extension range of the near-field tail vortex, the shape of the formation, the members' desired positions on the formation structure, and the priority of each desired position are planned. The higher the residual current of the cluster members, the closer the desired position is to the front of the formation, and the lower the priority of the desired position.

[0007] S2: Establish a method for estimating the average remaining energy of cluster members, update the energy information of other members of the formation in real time during the flight, and calculate the average remaining energy of cluster members.

[0008] S3: Set a low energy difference percentage threshold. When the difference between the remaining energy of a member machine and the average remaining energy of the cluster members exceeds the threshold, a location exchange request message is sent.

[0009] S4: Design a location exchange confirmation mechanism. After receiving a location exchange request, each member whose remaining energy is higher than the average remaining energy of the cluster members will feedback the current status information. The publisher of the location exchange request information evaluates the feedback information, selects the location exchange object based on the distance and remaining power of the feedback, and sends a location exchange confirmation request to the selected object.

[0010] S5: Design a location exchange confirmation feedback mechanism. After receiving the location exchange confirmation request, the member machine will feedback confirmation information to the sender of the location exchange confirmation request. If location exchange confirmation requests are received from multiple members at the same time, one of the senders will be selected based on the status of the request sender to feedback confirmation information, and rejection information will be fed back to the remaining senders.

[0011] S6: After receiving the feedback rejection information, the sender of the location exchange request information reselects a member device to send a location exchange confirmation request based on the feedback status information.

[0012] S7: Design the position transfer trajectory. After the sender of the position exchange confirmation message receives the feedback confirmation message, it moves independently along the position exchange trajectory relative to the formation as a whole, and each moves to the other's position. If it is detected that multiple members are currently transferring positions at the same time, the height offset is set based on the initial member priority, and each transfer member moves along a different height. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the implementation process of a method for maintaining energy consistency of a drone cluster provided in this embodiment.

[0014] Figure 2 It is a schematic diagram of the pre-planned formation provided in this embodiment.

[0015] Figure 3 Schematic diagram of the position transfer trajectory provided in this embodiment. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0017] In an embodiment of the present invention, a method for maintaining energy consistency of a drone cluster is proposed, such as Figure 1 As shown, the specific steps include:

[0018] like Figure 2 As shown in the figure, a pyramid formation is planned based on the distance between the wingtip vortex center and the extension area of ​​the near-field tail vortex. The number of members in each row of the formation increases from front to back. Except for the frontmost member, the rest of the members are within the wingtip vortex range of the front member. The formation position priority increases from front to back and from left to right.

[0019] Assign initial priorities to each member so that they form an initial formation based on position priority.

[0020] Each member broadcasts its remaining power E at 1HZ frequency s , and based on the formula Calculate the average residual energy of the cluster members, where N is the total number of members.

[0021] Set the low energy difference percentage threshold as σ. When the position exchange request information is broadcast periodically.

[0022] After receiving the location exchange request, each member whose residual energy is higher than the average residual energy of the cluster members will feedback the current status information. The publisher of the location exchange request information sorts the information of all status information feedback providers in order from low to high cost based on the cost formula (1), and sends a location exchange confirmation request to the highest ranked feedback provider.

[0023]

[0024] where Er=E i -E s is the energy difference between the feedbacker and the publisher, Dr is the distance between the feedbacker and the publisher, ω1 and ω2 are weight parameters.

[0025] After receiving the location exchange confirmation request, the member machine feeds back confirmation information to the sender of the location exchange confirmation request. If the member machine receives location exchange confirmation requests from multiple members at the same time, the member machine selects the request issuer to feed back confirmation information based on the cost formula (1) and feeds back rejection information to the remaining request issuers.

[0026] After receiving the feedback rejection information, the publisher of the location exchange request information reselects the feedback receiver based on the ranking to send a location exchange confirmation request.

[0027] After the publisher and the feedback receiver confirm the exchanged information, they exchange positions along the upward and downward trajectories as shown in the figure.

[0028] If there are multiple members transferring positions at the same time, based on the initial member priority p, the layer height difference h d , set the height offset h c =ph d , each member moves along different heights.

[0029] The above are only preferred embodiments of the present invention, but do not limit the patent scope of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features with equivalent ones. Any equivalent structure made by using the contents of the present invention specification and drawings, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present invention.

Claims

1. A method for maintaining energy consistency of a drone cluster, characterized in that: The method comprises the steps of: Step 1: Plan the formation. Based on the distance between the wingtip vortex centers and the extension range of the near-field tail vortex, plan the shape of the formation, the expected positions of the members in the formation structure, and the priority of each expected position. Step 2: Establish a method for estimating the average remaining energy of cluster members, update the energy information of other members of the formation in real time during the flight, and calculate the average remaining energy of cluster members; Step 3: Set a low energy difference percentage threshold. When the difference between the remaining energy of a member machine and the average remaining energy of the cluster members exceeds the threshold, a location exchange request message is sent. Step 4: Position exchange confirmation. After receiving the position exchange request, each member whose residual energy is higher than the average residual energy of the cluster members feeds back the current state information. The publisher of the location exchange request information evaluates the feedback information, selects the location exchange object based on the distance and remaining power of the feedback object, and sends a location exchange confirmation request to the selected object; Step 5: Location exchange confirmation feedback. After receiving the location exchange confirmation request, the member machine feeds back confirmation information to the sender of the location exchange confirmation request. If location exchange confirmation requests are received from multiple members at the same time, one of the senders is selected to feed back confirmation information based on the status of the request sender, and rejection information is fed back to the remaining senders. Step 6: After receiving the feedback rejection information, the sender of the location exchange request information reselects a member device to send a location exchange confirmation request based on the feedback status information; Step 7: Exchange positions based on the position transfer trajectory. After the sender of the position exchange confirmation request receives the feedback confirmation information, it and the feedback sender independently move along the position exchange trajectory relative to the formation as a whole, and each transfers to the other's position. If it is detected that multiple members are currently transferring positions at the same time, the height offset is set based on the initial member priority, and each transferred member moves at a different height.

2. A method for maintaining energy consistency of a drone cluster as claimed in claim 1, characterized in that: When the method performs formation shape planning in step 1, the closer the desired position is to the front end of the formation, the lower the priority of the desired position; except for the frontmost member, the remaining members are within the effective area of ​​the wingtip vortex of the front member.

3. A method for maintaining energy consistency of a drone cluster as claimed in claim 1, characterized in that: When the method performs the estimation of the average remaining energy of cluster members in step 2, each member should periodically send its own remaining energy information, and update the remaining energy information of other members and calculate the average member remaining energy in real time.

4. A method for maintaining energy consistency of a drone cluster as claimed in claim 1, characterized in that: In steps 4, 5 and 6 of the method, when members select location exchange objects from each other, the location exchange request issuer needs to select the location exchange object, and the location exchange request feedbacker can accept or reject the request.

5. A method for maintaining energy consistency of a drone cluster as claimed in claim 1, characterized in that: In step seven of the method, when multiple groups of members exchange positions, the position exchange request issuer and the feedback responder exchange positions along the upper trajectory and the lower trajectory of the formation flight altitude respectively; if there are multiple members currently transferring positions at the same time, the altitude offset is set based on the preset member priority, and each transferred member moves along a different altitude.

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