CN111601355A - Optimal path selection method in formation maintenance topology of wireless ultraviolet light cooperation unmanned aerial vehicle - Google Patents

Abstract

The invention provides a method for selecting an optimal path in a formation maintenance topology of a wireless ultraviolet light cooperation unmanned aerial vehicle, which comprises the steps of firstly establishing an inter-aircraft communication path by utilizing an ultraviolet light non-direct-view single scattering model; setting a path weight by using the path loss of the communication link and the residual energy of the node; and finally, obtaining the optimal communication path between any unmanned aerial vehicle nodes in the formation by using the path weight through a Floyd algorithm. The invention adopts the wireless ultraviolet light to cooperate the unmanned aerial vehicle swarm formation flying, has the advantages of all weather, non-direct vision, no radio frequency interference, secret communication and the like, and can provide effective guarantee for the unmanned aerial vehicle swarm to smoothly execute tasks in strong electromagnetic interference environment. The path weight is set according to the path loss of the communication link and the node residual energy, so that the condition that the same path is selected for many times and the energy of the path node is ignored in the communication process can be avoided, the node is dead early, and the life cycle of the network is prolonged.

Description

Optimal path selection method in formation keeping topology of wireless UV cooperative UAV

technical field

The invention belongs to the technical field of optoelectronic information, and in particular relates to an optimal path selection method in a formation maintaining topology of a wireless ultraviolet cooperative unmanned aerial vehicle.

Background technique

In recent years, the emerging industries related to drones have ushered in a period of rapid development. UAVs have played an important role in the civilian and military fields. Due to the limited computing, detection and operation capabilities of a single UAV, the use of multi-UAV cooperation can fully improve the ability of UAVs to perform tasks. The UAV "swarm" formation is composed of a group of small UAVs that operate autonomously in a network. Improve task completion efficiency.

The UAV communication network has the characteristics of self-organization, and its electronic system is easily affected by electromagnetic pulses, radio frequency interference, high-intensity radiation fields, etc. Therefore, it is very urgent to adopt an internal communication method of UAV swarms with strong anti-interference ability. of. The advantages of using wireless ultraviolet light communication technology in drone swarm flight are as follows: low background noise; strong anti-interference ability; all-weather non-line-of-sight (NLOS) communication; low power consumption consumption is easy to integrate. The application of wireless ultraviolet light communication technology to the communication between drone swarms can meet the reliable and stealthy communication requirements of drones in complex battlefield environments.

The UAV formation has limited energy in practical applications. When the UAV is in the process of maintaining the formation, when a UAV transmits a message or issues an instruction to any other UAV, it can set a reasonable path weight and find a path. The path with the least communication cost can effectively reduce the transmission power of a single node and the total power of the system, avoid selecting the same path multiple times during the communication process and ignore the energy of the node, balance the energy consumption of the UAV node, and prolong the UAV network. The life cycle. Therefore, an optimal path selection method in the formation-keeping topology of wireless UV cooperative UAVs is proposed. .

It is noted that this section is intended to provide a background or context for the embodiments of the invention that are recited in the claims. The descriptions herein are not admitted to be prior art by inclusion in this section.

SUMMARY OF THE INVENTION

The purpose of the invention is to provide an optimal path selection method in the formation keeping topology of the wireless ultraviolet light cooperative UAV, solve the reliability problem of the communication between the UAVs in the formation, balance the energy consumption of the UAV nodes, and prolong the network life. cycle.

For achieving the above object, the present invention adopts the following technical solutions:

The optimal path selection method in the formation keeping topology of the wireless ultraviolet cooperative UAV is characterized by comprising the following steps:

S1: Establish an inter-machine communication path by using the non-direct-sighted single-scattering model of ultraviolet light;

S2: Use the path loss of the communication link and the remaining energy of the node to set the path weight;

S3: The optimal communication path between any UAV nodes in the formation is obtained by using the path weights through the Floyd algorithm.

Further, above-mentioned step S2 is as follows:

S201: Calculate the path loss of the communication link of the two UAV nodes;

Based on the ellipsoidal coordinate system, the ultraviolet light emitting device and the receiving device are placed at the two foci of the ellipsoidal coordinate system, respectively, and the path loss of the ultraviolet non-direct line of sight communication is:

L=ξr ^α (1)

Among them, r is the communication distance, ξ is the path loss factor, and α is the path loss index;

S202: Calculate the remaining energy of the UAV node;

After the formation is assembled, the remaining energy of each UAV node is:

Among them, e ₀ is the initial energy of the UAV node, P is the mobile energy consumption, m _p is the payload mass in kg, m _v is the mass of the UAV in kg, r is the lift-drag ratio, η is the energy transfer efficiency of the motor and the propeller, p is the power consumption of the electronic device, the unit is kW, v=d _ii /t is the average speed during the assembly process of the UAV, the unit is km/h, and d _ii is the UAV The distance from the initial position to the fixed position in the formation during the assembly process, t is the assembly time;

S203: Set the path weight;

Set the path weights according to the calculated path loss and the remaining energy of each node:

为通信链路路径损耗均值，

为节点剩余能量均值，e_rest为节点剩余能量。Among them, α ₁ and α ₂ are weight coefficients, L is the path loss of the communication link,

is the mean value of the path loss of the communication link,

is the average residual energy of the node, and e _rest is the residual energy of the node.

Further, above-mentioned step S3 is as follows:

S301: Initialize the path weight between the UAVs UAV _i and UAV _j , when the two UAVs can communicate directly, use step S2 to calculate the path weight between the UAVs UAV _i and UAV _j ; When the communication between two UAVs needs to pass through other UAV nodes for message forwarding, the path weight is infinite;

S302: Add vertex UAV ₁ between UAV _i and UAV _j , compare the path weights of UAV _i , UAV ₁ and UAV _j , and UAV _i and UAV _j , and take the path with the smaller weight as UAV _i to UAV _j The optimal path with vertex number not greater than 1;

S303: Add vertex UAV ₂ between UAV _i and UAV _j to obtain UAV _i ,...,UAV ₂ and UAV ₂ ,...,UAV _j , where UAV _i ,...,UAV ₂ is The optimal path from UAV _i to UAV ₂ and the intermediate vertex number is not greater than 1; UAV ₂ , . . . , UAV _j is the optimal path from UAV ₂ to UAV _j and the intermediate vertex number is not greater than ₁ ; ..., UAV ₂ , ..., UAV _j are compared with the optimal path obtained in step S302, and the shorter path is taken as the optimal path from UAV _i to UAV _j and the intermediate vertex number is not greater than 2;

S304: By analogy, after n comparisons and corrections, in the n-1 step, the optimal path from UAV _i to UAV _j and the intermediate vertex number is not greater than n-1 will be obtained, which is any arbitrary path in the UAV formation. The optimal communication path between two nodes UAV _i to UAV _j .

Beneficial effects of the present invention:

1) The invention adopts wireless ultraviolet light cooperative drone swarm formation flight, which has the advantages of all-weather, non-direct view, free from radio frequency interference and stealth communication, etc. Effective protection.

2) The present invention sets the path weight according to the path loss of the communication link and the remaining energy of the node, which can avoid selecting the same path for many times in the communication process and ignore the energy situation of the path node, thereby causing the premature death of the node and prolonging the network. The life cycle.

Description of drawings

Fig. 1 is the flow chart of the optimal path selection method in the formation keeping topology of the wireless ultraviolet cooperative unmanned aerial vehicle of the present invention;

Fig. 2 is the communication model diagram of ultraviolet light non-direct view single scattering communication of the present invention;

Fig. 3 is the relation diagram of sending and receiving elevation angle and path loss of the present invention;

FIG. 4 is a topological structure diagram of the UAV formation flight network of the present invention.

Detailed ways

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments, however, can be embodied in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features or characteristics may be combined in any suitable manner in one or more embodiments.

As shown in Figure 1, it is assumed that the initial state of the swarm UAV nodes is the same before the assembly, and after the UAVs are assembled and reach the fixed position in the formation, the remaining energy of the UAV nodes is different. The wireless ultraviolet light is used to assist the communication between the swarm UAVs, and the path loss of the communication link is obtained according to the characteristics of the ultraviolet light NLOS communication. The path weight is set according to the path loss and the remaining energy of the node, and the Floyd algorithm is used to select the optimal communication path between any nodes in the UAV formation, which can avoid selecting the same node for multiple times to forward messages during the communication process, resulting in node energy Insufficient and fatal situations, effectively extending the life cycle of the drone network.

The present invention is an optimal path selection method in the formation maintaining topology of the wireless ultraviolet cooperative unmanned aerial vehicle, which is specifically implemented according to the following steps:

Step 1: Establish an inter-machine communication path using a non-direct-sighted single-scattering model of ultraviolet light.

As shown in FIG. 2 , based on the ellipsoid coordinate system, the ultraviolet light emitting device and the receiving device are respectively placed on two foci of the ellipsoid coordinate system. θ ₁ is the transmitting elevation angle, θ ₂ is the receiving elevation angle, φ ₁ is the transmitting end divergence angle, and φ ₂ is the receiving end field-of-view angle.

The path loss of UV non-line-of-sight communication is:

L=ξr ^α (1)

Among them, r is the communication distance, ξ is the path loss factor, and α is the path loss index. The values of α and ξ depend on the transmit end divergence angle φ ₁ , the transmit elevation angle θ ₁ , the receive end angle of view φ ₂ , and the receive end angle θ ₂ . When the transmit end divergence angle and the receive end angle of view are fixed, communication at different transmit and receive elevation angles is possible. Corresponding to different values of α and ξ, that is, the path loss values of the communication links between the UAVs are different.

Step 2, using the path loss of the communication link and the remaining energy of the node to set the path weight.

Step 2.1, calculate the path loss of the communication link between the two UAV nodes.

It can be seen from step 1 that when φ ₁ and φ ₂ are fixed, the space angle parameters θ ₁ and θ ₂ of the transceiver end between the UAVs are randomly given, and the path loss between the two UAVs can be determined. As shown in the relationship between the sending and receiving elevation angle and path loss in Figure 3, when φ ₁ = 17° and φ ₂ = 30°, the spatial angle parameters θ ₁ and θ ₂ of the transmitter and receiver between the UAVs are randomly given, and the two have no The path loss of the human-machine communication link can be determined.

Step 2.2, calculate the remaining energy of the UAV node.

Assuming that the energy of each UAV node is equal at the initial position, and each UAV moves from the initial position to the fixed position in the formation during the assembly process, the communication energy consumed by it is approximately equal, and the mobile energy consumption is much greater than the communication energy consumption, so Only mobile energy consumption is considered during the build-up process. After the formation is assembled, the remaining energy of each UAV node is:

Among them, e ₀ is the initial energy of each UAV node, P is the mobile energy consumption, m _p is the mass of the payload (kg), m _v is the mass of the UAV (kg), r is the lift-drag ratio, and η is The energy transfer efficiency of the motor and the propeller, p is the power consumption of the electronic device (kW), v=d _ii /t is the average speed (km/h) during the UAV assembly process, and d _ii is the UAV assembly process. The distance from the initial position to the fixed position in the formation, t is the assembly time.

Step 2.3, set the path weight.

Figure 4 shows the topology of the communication network between UAVs in a formation. Each UAV corresponds to a fixed ID number. Numbers 1-9 represent nine UAVs respectively, and the connections between UAVs indicate Communication path, the path between two nodes means that the two nodes are within the communication range of each other and can communicate directly. At least one path is connected between any two UAVs in the figure. The link of direct communication sets the path weight by formula (3), and the weight of the path that cannot communicate directly is set to infinity.

为通信链路路径损耗均值，

为节点剩余能量均值，e_rest为节点剩余能量。Among them, α ₁ and α ₂ are weight coefficients, L is the path loss of the communication link,

is the mean value of the path loss of the communication link,

is the average residual energy of the node, and e _rest is the residual energy of the node.

Step 3, the Floyd algorithm uses the path weight to obtain the optimal communication path between any UAV nodes in the formation.

Step 3.1, initialize the path weight between UAV _i and UAV _j in step 2.

Step 3.2, add vertex UAV ₁ between UAV _i and UAV _j , compare the path weights of (UAV _i , UAV ₁ , UAV _j ) and (UAV _i , UAV _j ), and take the path with the smaller weight as UAV _i to The optimal path for UAV _j with vertex number not greater than 1.

Step 3.3, add vertex UAV ₂ between UAV _i to UAV _j to obtain (UAV _i ,...,UAV ₂ ) and (UAV ₂ ,...,UAV _j ). Among them, (UAV _i ,...,UAV ₂ ) is the optimal path from UAV _i to UAV ₂ and the intermediate vertex number is not greater than 1; (UAV ₂ ,...,UAV _j ) is the optimal path from UAV ₂ to UAV _j And the optimal path with the intermediate vertex number not greater than 1, these two paths have been obtained in step 3.2. Compare (UAV _i ,...,UAV ₂ ,...,UAV _j ) with the optimal path obtained in step 3.2, and take the shorter path as UAV _i to UAV _j and the intermediate vertex number is not greater than 2 the optimal path of

Step 3.4, and so on, after n comparisons and corrections, in step (n-1), the optimal path from UAV _i to UAV _j and the intermediate vertex number is not greater than n-1 will be obtained, which is unmanned. The optimal communication path from any two nodes UAV _i to UAV _j in the aircraft formation.

Example:

Step 1, each drone is equipped with an ultraviolet light transceiver device, and the ultraviolet light emission device emits an ultraviolet wavelength of 260nm and a luminous power of 0.6mw.

计算编队集结完毕之后各无人机节点的剩余能量。Step 2: Fix the divergence angle of the transmitter and the field of view of the receiver, the divergence angle of the transmitter is φ ₁ =17°, the field of view of the receiver is φ ₂ =30°, and the spatial angle parameters of the transmitter and receiver between the drones are randomly given. , the relationship between the transmission and reception elevation angle and path loss is shown in Figure 3. m _p = 2 kg, m _v = 8 kg, r = 3, η = 0.5, p = 0.1 kW, e ₀ = 300 J, v = d _ii /t. by formula

Calculate the remaining energy of each UAV node after the formation is assembled.

及图4无人机编队飞行网络拓扑结构图，计算得到无人机网络拓扑的路径权值矩阵为:By the path weight formula

And Fig. 4 UAV formation flight network topology diagram, the path weight matrix that calculates the UAV network topology is:

A＝[0 0.9950 1.2566 1.0788 inf inf inf inf inf；0.9950 0 1.2314 infinf 0.9912 1.8027 inf inf；1.2566 1.2314 0 1.0314 0.9192 0.9811 inf inf inf；1.0788 inf 1.0314 0 1.0148 inf inf inf inf；inf inf 0.9192 1.0148 0 inf infinf 1.0377 ;inf 0.9912 0.9811 inf inf 0 inf 0.8563 1.0583; inf 1.8027 inf inf inf 0 0.8353 inf; inf inf inf inf 0.8563 0.83530 0.9744;

Step 3, simulate according to the Floyd algorithm, input any two UAV node IDs as the starting point and end point, and output the node ID of the optimal communication path, which is the optimal communication selected when any two nodes in the UAV formation communicate with each other. path.

(1) Input start point: 1; input end point: 9;

Optimal communication path: 1-2-6-9

(2) Input start point: 3; input end point: 7;

Optimal communication path: 3-6-8-7

Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the invention which follow the general principles of the invention and which include common knowledge or conventional techniques in the art not disclosed by the invention . The specification and examples are to be regarded as exemplary only, with the true scope and spirit of the invention being indicated by the appended claims.

Claims (3)

1. The optimal path selection method in the formation keeping topology of the wireless ultraviolet cooperative unmanned aerial vehicle, is characterized in that, comprises the following steps: S1: Establish an inter-machine communication path by using the non-direct-sighted single-scattering model of ultraviolet light; S2: Use the path loss of the communication link and the remaining energy of the node to set the path weight; S3: The optimal communication path between any UAV nodes in the formation is obtained by using the path weights through the Floyd algorithm. 2. the optimal path selection method in the wireless ultraviolet cooperative unmanned aerial vehicle formation keeping topology according to claim 1, is characterized in that, described step S2 is specifically as follows: S201: Calculate the path loss of the communication link of the two UAV nodes; Based on the ellipsoidal coordinate system, the ultraviolet light emitting device and the receiving device are placed at the two foci of the ellipsoidal coordinate system, respectively, and the path loss of the ultraviolet non-direct line of sight communication is: L=ξr ^α (1) Among them, r is the communication distance, ξ is the path loss factor, and α is the path loss index; S202: Calculate the remaining energy of the UAV node; After the formation is assembled, the remaining energy of each UAV node is:

Among them, e ₀ is the initial energy of the UAV node, P is the mobile energy consumption, m _p is the payload mass in kg, m _v is the mass of the UAV in kg, r is the lift-drag ratio, η is the energy transfer efficiency of the motor and the propeller, p is the power consumption of the electronic device, the unit is kW, v=d _ii /t is the average speed during the assembly process of the UAV, the unit is km/h, and d _ii is the UAV The distance from the initial position to the fixed position in the formation during the assembly process, t is the assembly time; S203: Set the path weight; Set the path weights according to the calculated path loss and the remaining energy of each node:

Among them, α ₁ and α ₂ are weight coefficients, α ₁ +α ₂ =1, L is the path loss of the communication link,

is the mean value of the path loss of the communication link,

is the average residual energy of the node, and e _rest is the residual energy of the node. 3. the optimal path selection method in the wireless ultraviolet cooperative unmanned aerial vehicle formation maintaining topology according to claim 1, is characterized in that, described step S3 is specifically as follows: S301: Initialize the path weight between the UAVs UAV _i and UAV _j , when the two UAVs can communicate directly, use step S2 to calculate the path weight between the UAVs UAV _i and UAV _j ; When the communication between two UAVs needs to pass through other UAV nodes for message forwarding, the path weight is infinite; S302: Add vertex UAV ₁ between UAV _i and UAV _j , compare the path weights of UAV _i , UAV ₁ and UAV _j , and UAV _i and UAV _j , and take the path with the smaller weight as UAV _i to UAV _j The optimal path with vertex number not greater than 1; S303: Add vertex UAV ₂ between UAV _i and UAV _j to obtain UAV _i ,...,UAV ₂ and UAV ₂ ,...,UAV _j , where UAV _i ,...,UAV ₂ is The optimal path from UAV _i to UAV ₂ and the intermediate vertex number is not greater than 1; UAV ₂ , . . . , UAV _j is the optimal path from UAV ₂ to UAV _j and the intermediate vertex number is not greater than ₁ ; ..., UAV ₂ , ..., UAV _j are compared with the optimal path obtained in step S302, and the shorter path is taken as the optimal path from UAV _i to UAV _j and the intermediate vertex number is not greater than 2; S304: By analogy, after n comparisons and corrections, in the n-1 step, the optimal path from UAV _i to UAV _j and the intermediate vertex number is not greater than n-1 will be obtained, which is any arbitrary path in the UAV formation. The optimal communication path between two nodes UAV _i to UAV _j .

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