A method and device for selecting a directional charging vehicle residence location in a wireless rechargeable sensor network

Abstract

The application discloses a directional charging car resident position selection method and device in a wireless rechargeable sensor network. The method comprises the following steps: constructing a charging queue to be charged according to the time sequence of charging requests sent by nodes in the wireless rechargeable sensor network, and selecting a circle center; determining a directional charging calculation range based on the selected circle center; if only the circle center node is in the directional charging calculation range, moving the charging car to the circle center node to perform directional charging; otherwise, calculating the priority of the nodes other than the circle center node in the directional charging calculation range, and constructing a priority queue; selecting a charging car resident position and a charging method according to the number of nodes in the priority queue, and performing directional charging on the nodes. The method can make the directional charging more efficient, thereby maximizing the use of energy resources and improving the reliability and stability of the sensor network.

Description

Technical Field

[0001] This invention belongs to the field of wireless rechargeable sensor network technology, specifically relating to a method and device for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network. Background Technology

[0002] Wireless Sensor Networks (WSNs) have been widely used in many fields, such as environmental monitoring and intelligent transportation. However, the energy consumption of nodes in WSNs has always been a major bottleneck restricting their development. Since the energy supply of nodes comes from limited resources such as batteries, extending the lifetime of nodes has been a hot research topic. Wireless Rechargeable Sensor Networks (WRSNs) employ Wireless Power Transfer (WPT) technology to provide sensors with a wireless, reliable, and continuous energy supply through a power supply unit, thus promoting the development of wireless rechargeable sensor networks.

[0003] Existing charging methods mainly include omnidirectional WPT (Wireless Radio Presentation) and directional WPT. Omnidirectional WPT refers to the charger broadcasting radio electromagnetic waves uniformly in all directions, allowing nodes to receive energy at any location within a limited transmission range. To improve energy utilization, directional WPT uses energy beams to converge radiated energy from a limited number of directions, concentrating the radiated energy in a limited direction using a high-gain directional antenna, making charging more precise.

[0004] For directional WPT technology, existing research focuses on the impact of parameters such as the distance and angle between the charging vehicle and the node on the charging effect. Placing the charging vehicle's dwell point at the default fixed dwell point may lead to a decrease in charging efficiency. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a method and apparatus for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network. The charging vehicle's location is selected based on the remaining battery power of the nodes and the distance between nodes, enabling directional charging of the nodes and extending the network's operating time.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, comprising:

[0008] A queue of devices to be charged is constructed according to the time sequence in which nodes in the wireless rechargeable sensor network send charging requests, and a center point is selected. The calculation range for directional charging is determined based on the selected center point.

[0009] If the directional charging calculation range only includes the center node, then the charging vehicle is moved to the center node for directional charging; otherwise, the priority of the nodes other than the center node within the directional charging calculation range is calculated, and a priority queue is constructed.

[0010] Based on the number of nodes in the priority queue, the charging vehicle's stationing location and charging method are selected to perform targeted charging on the nodes.

[0011] Furthermore, the step of constructing a charging queue according to the time sequence in which nodes in the wireless rechargeable sensor network send charging requests includes:

[0012] Set a request threshold δ1. When the node's power is lower than the request threshold δ1, send a charging request and set the charging flag M=0. Build a queue Q to be charged according to the order in which the nodes send charging requests.

[0013] Furthermore, the selection of the center point, and the determination of the directional charging calculation range based on the selected center point, includes:

[0014] Select the first node B in the queue to be charged as the center, and draw a circle with a radius of twice the charging distance of the charging vehicle, 2R, as the calculation range for directional charging, where R is the charging distance of the charging vehicle.

[0015] Furthermore, the calculation of the priority of nodes other than the center node within the directional charging calculation range, and the construction of a priority queue, includes:

[0016] When the power of the first node in the charging queue Q is lower than the power threshold δ2, priority is assigned to the nodes in the charging queue in sequence; the priority is the ratio of the node's current remaining power to the request threshold δ1.

[0017] Priority is calculated based on the node allocation priority and the distance between the node and the center node, as follows:

[0018] F i =c1×f i +c2×s i ;

[0019] Among them, F i For node n i The priority of f is given by coefficients c1 and c2, which satisfy c1 + c2 = 1. i For node n i Allocation priority, s i The calculation is as follows:

[0020] si =d i / 2R;

[0021]

[0022] Where, d i For node n i Distance from the center node, (x i ,y i ) and (x B ,y B ) represent nodes n respectively i The coordinates of the center node;

[0023] Construct a priority queue P for nodes within the directional charging calculation range, excluding the center node, in ascending order of priority.

[0024] Furthermore, if the directional charging calculation range only includes the center node, then moving the charging vehicle to the center node for directional charging includes:

[0025] Move the charging vehicle to the center node and charge it to full capacity with the minimum charging expansion angle θ1 as the center node.

[0026] Furthermore, the step of selecting the charging vehicle's parking location and charging method based on the number of nodes in the priority queue, and performing targeted charging on the nodes, includes:

[0027] If the priority queue P contains only one node A, then the distance d between nodes A and B is used as the basis for priority queue P. AB Based on the relationship between 2R and R, the mobile charging vehicle moves to the calculated dwell point L and uses the corresponding charging method to charge nodes A and B respectively;

[0028] If the priority queue P has more than one node, then only the first two nodes A and C are selected, and the distances d between nodes A, B, and C are calculated and compared. AB d AC d BC Let the longest distance be d. max According to d max Based on the relationship between 4R, 2R, and R, the mobile charging vehicle moves to the calculated dwell point L and starts charging nodes A, B, and C using the corresponding charging methods.

[0029] After fully charging the center node B, and charging all nodes except the center node B to a level not less than the charging threshold δ3, set the charging flag M of the nodes after this charging to 0, and remove them from the charging queue Q.

[0030] Nodes that send new requests during the charging process are added to the charging queue Q in the order the requests arrive. The center of the circle is selected and the directional charging calculation range is calculated. A priority queue P for nodes within the directional charging calculation range is constructed. The charging vehicle's stationing location and charging method are selected in the above manner, and directional charging is performed on the nodes. The charging process continues until the charging queue is empty or the charging vehicle's energy is insufficient to complete the next charging cycle. The charging vehicle then returns to the base station to replenish its energy.

[0031] Furthermore, if the priority queue P contains only one node A, the distance d between nodes A and B is used as the criterion. AB Given the relationship between 2R and R, the mobile charging vehicle travels to the calculated dwell point L and charges nodes A and B using the corresponding charging methods, including:

[0032] If R <d AB If the radius is ≤2R, then the charging vehicle's stopping point L is selected as the midpoint of the line connecting node A and the central node B. The charging expansion angle θ1 is used to first charge the central node B, with the charging center direction... Point in the direction of the center node B; after the center node B is fully charged, rotate the angle to align with the charging center direction. Point in the direction of node A to charge node A until the charge of A is not less than the charging threshold δ3;

[0033] If d AB If R ≤ R, then the charging vehicle's parking point L is located at the center node B, and charging is applied to both nodes A and B simultaneously with a charging expansion angle θ1, with the charging center direction... Point in the direction of node A, and stop charging when the center node B is fully charged and the charge of node A is not less than the charging threshold δ3.

[0034] Furthermore, if there is more than one node in the priority queue P, charging nodes A, B, and C includes:

[0035] S1, if 2R <d max If ≤4R, then only node A, which is at the beginning of the priority queue P, is retained, and node C is ignored. Nodes A and B are charged in the manner that there is only one node A in the priority queue P.

[0036] S2, if R <d max ≤2R, and d max If it is unique, then the distance is d. max Does the two nodes include the center node B?

[0037] If included, then the dwell point L is selected at the midpoint of the line connecting the two nodes;

[0038] If not included, then choose the dwell point L at the second longest distance d′. maxAt the midpoint of the line connecting the two endpoints, if d AB With d BC If both are the second longest distances, then choose d. AB As d′ max ;

[0039] If d max If not unique, then choose the longest distance including the center node B as d. max If the distance between the center node B and nodes A and C is d max Then the distance between nodes A and B is chosen as the longest distance, and the dwelling point L is located at d. max The midpoint of the line connecting the two endpoints;

[0040] The charging expansion angle is set to θ1, and the charging center direction is... First, point in the direction of the center node B to charge the center node B to full capacity; then rotate by π angle to make the charging center direction The node pointing to the other end of the connection is charged until the charge level is not less than the charging threshold δ3;

[0041] Finally, determine if the distance from the dwell point L to the remaining uncharged node is greater than R. If it is, do not charge the remaining uncharged node; otherwise, set the charging center direction... Point to the remaining uncharged node and charge it until the charge level is not less than the charging threshold δ3;

[0042] S3, if d max ≤R, take the distance as d max Let the node with the lowest remaining energy among the two nodes be the dwell point L. Let L be the vertex, and the lines connecting the other two nodes to L be the edges. Let θ be the angle formed by these edges. k Compare θ k The magnitude of θ1, if θ k If the angle is less than θ1, then let θ1 be the charging expansion angle; otherwise, let θ... k For charging expansion angle;

[0043] Using the bisector of the charging expansion angle as the charging center direction, charge the three nodes simultaneously until the central node B is fully charged, and the charge levels of nodes A and C are not less than the charging threshold δ3.

[0044] Furthermore, the request threshold δ1, the power threshold δ2, and the charging threshold δ3 satisfy the following:

[0045] δ2<δ1<δ3.

[0046] The present invention also provides a device for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, for implementing the aforementioned method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, the device comprising:

[0047] The directional charging calculation range determination module is used to construct a queue to be charged according to the time order in which nodes in the wireless rechargeable sensor network send charging requests, select a center, and determine the directional charging calculation range based on the selected center.

[0048] The priority queue construction module is used to calculate the priority of nodes other than the center node within the directional charging calculation range and construct a priority queue.

[0049] The charging decision module is used to make charging decisions based on the number of nodes within the directional charging calculation range, as follows:

[0050] If the directional charging calculation range only includes the center node, then the charging vehicle is moved to the center node for directional charging; otherwise, based on the number of nodes in the priority queue, the charging vehicle's stationing position and charging method are selected to perform directional charging on the node.

[0051] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0052] This invention provides a method for selecting the charging vehicle's stopping point in directional charging. This method determines the charging stopping point of the vehicle, avoiding energy waste in omnidirectional charging and making directional charging more efficient. This maximizes the utilization of energy resources, improves the reliability and stability of the sensor network, and extends the lifespan of the wireless rechargeable sensor network. After selecting the first charging node, other nodes around that node are also considered, allowing for simultaneous charging of two or three nodes, reducing energy waste during movement. Attached Figure Description

[0053] Figure 1 This is a flowchart of a method for selecting the parking position of a charging vehicle in directional charging, provided by an embodiment of the present invention;

[0054] Figure 2 This invention provides a directional charging model between the charging vehicle and the node.

[0055] Figure 3 In this embodiment of the invention, the priority queue has only one node charging. Figure 3 (a) is R <d AB In the case of ≤2R, Figure 3 (b) is d AB The case where ≤R;

[0056] Figure 4 In this embodiment of the invention, the priority queue has at least two nodes charging. Figure 4 (a), (b), and (c) are R <d max Examples of methods for ≤2R Figure 4 (a) is R <d maxWhen ≤2R, the distance between B and C is d. max When A is within the charging radius, Figure 4 (b) is R <d max When ≤2R, the distance between B and C is d. max If A is not within the charging radius, Figure 4 (c) is R <d max When ≤2R, the distance between B and C is d′. max When A is within the charging radius, Figure 4 (d) is d max When ≤R, the distance between B and C is d. max The situation. Detailed Implementation

[0057] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0058] This invention provides a method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, comprising:

[0059] A queue of devices to be charged is constructed according to the time sequence in which nodes in the wireless rechargeable sensor network send charging requests, and a center is selected to determine the calculation range for directional charging based on the center.

[0060] If the only node within the directional charging calculation range is the center node, then the charging vehicle is moved to that center node for charging; otherwise, the priority of nodes other than the center node within the directional charging calculation range is calculated, and a priority queue is constructed.

[0061] Based on the number of nodes in the priority queue, the charging vehicle's resting point and charging method are selected to perform targeted charging on the nodes.

[0062] In this invention, the first node in the queue to be charged is taken as the center node, and a circle is drawn with a radius of twice the charging distance of the charging vehicle as the calculation range for directional charging.

[0063] In this invention, priorities are assigned to nodes in the charging queue based on their remaining power, and priority queues are constructed by calculating the priority of nodes other than the center node within the directional charging calculation range based on the assigned priorities.

[0064] In this invention, the priority value is the ratio of the node's current remaining power to a preset threshold.

[0065] In this invention, priority is calculated based on the priority assigned to the current node and the distance between the current node and the center node.

[0066] In this invention, nodes are constructed into a priority queue in ascending order of priority.

[0067] Based on the above inventive concept, an embodiment of the present invention provides a method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, the specific implementation process of which includes:

[0068] S1. Initialize the wireless rechargeable sensor network.

[0069] Specifically, this includes setting a node charging flag M, with all initial flags set to 1, indicating sufficient power. The locations of the node, base station, and charging vehicle are all known and can be represented by coordinates.

[0070] S2. Construct a charging queue Q.

[0071] Specifically: Set a threshold δ1. When a node's battery level is below the threshold δ1, set M=0, send a charging request, and construct a charging queue Q according to the order in which the nodes sent their charging requests.

[0072] S3. Select the center point to determine the calculation range for directional charging.

[0073] Specifically, draw a circle with the first node B of the queue to be charged Q as the center and 2R, which is twice the charging distance of the charging vehicle, as the radius.

[0074] S4. Assign priorities and calculate priority weights, then construct a priority queue.

[0075] Specifically, when the battery level of the first node in the charging queue Q is lower than the threshold δ2, priority is assigned to all nodes in the charging queue Q.

[0076] Determine whether there are any other nodes in the charging queue Q besides B within the circle. If not, the charging vehicle moves to the center node B and starts charging the center node B until it is fully charged, starting with the minimum charging expansion angle θ1. If there are other nodes, calculate the priority based on the priority assigned to the current node and the distance between the current node and the center node, and construct a priority queue P by increasing the priority of the nodes.

[0077] S5. Select the charging vehicle's parking point and charging method for the nodes in the priority queue.

[0078] If the priority queue contains only one node A, then the distance d between A and B is used as a guide. AB Based on the relationship between 2R and R, the charging vehicle moves to the calculated dwell point L and starts charging nodes A and B using the corresponding charging methods.

[0079] If there is more than one node in the priority queue, select only the first two nodes A and C, and calculate and compare the distance d between points A, B, and C. AB d AC d BC Let the longest distance be d.max According to d max Based on the relationship between 4R, 2R, and R, the charging vehicle moves to the calculated dwell point L and starts charging nodes A, B, and C using the corresponding charging methods. After node B is fully charged and all nodes except B are charged to a level not less than the threshold δ3, the node M after this charging is set to 0 and removed from the charging queue.

[0080] S6. Nodes that send new requests during the charging process are added to the charging queue Q in the order of their arrival. The first node in Q is selected as the center node, and a priority queue P for nodes within a radius of 2R is constructed to find the next resting point of the charging vehicle.

[0081] S7. Repeat the above operation to calculate the energy of the charging vehicle and the node until the charging queue is empty or the charging vehicle's energy is insufficient to complete the next charging. The charging vehicle then returns to the base station to replenish its energy.

[0082] Based on the same inventive concept, another embodiment of the present invention provides a method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, see [link to relevant documentation]. Figure 1 The specific implementation process includes:

[0083] Step 1: Initialize the wireless sensor network and build an energy transfer model for the nodes. The specific implementation method is as follows:

[0084] Set the node charging flag M, with all initial flags set to 1, indicating sufficient power.

[0085] The locations of nodes, base stations, and charging vehicles are all known and can be represented by coordinates, with the base station located at the center of the network.

[0086] Constructing a directional charging model, such as Figure 2 As shown, it represents the following:

[0087]

[0088]

[0089] Among them, P i Indicates the node n to be charged i The power of the received energy. The location of the charging vehicle and the node to be charged n i The direction of the line, θ is the charging expansion angle of the charging vehicle. The direction of the charging center is the bisector of the charging expansion angle, where α is... and The angle between the node and the charging vehicle is d, the distance between the node and the charging vehicle is R, the charging radius of the charging vehicle is c, the parameter for adjusting the vertical case of the equation is c, and the parameter for adjusting the short-distance transmission of the Fries free space equation is β.

[0090] In this embodiment, c is 0.1161 and β is 0.1. The meaning of μ is as follows:

[0091]

[0092] Where η is the rectification efficiency, A er It is the effective receiving area of ​​the node when it is being charged. It is the maximum effective transmission area of ​​the charging vehicle, L p λ represents polarization loss, λ represents wavelength, and P0 represents the power of energy transmitted during charging by the charging vehicle.

[0093] In this embodiment, the value of μ is 3.893.

[0094] Step 2: Set the node's request threshold δ1. When a node's remaining battery power is below δ1, it sends a charging request. A charging queue Q = {q1, q2, ..., q} is then created based on the order in which the charging requests are sent. m}, and select the first node B in the queue to be charged as the center, and draw a circle with a radius of twice the charging distance of the charging vehicle, 2R;

[0095] When the battery level of the first node in the queue is lower than the battery threshold δ2, priority f = {f1, f2, ..., f...} is assigned sequentially to the nodes in the charging queue. m},

[0096] It should be noted that the priority value is the ratio of the node's current remaining power to δ1.

[0097] Determine whether there are any other nodes in the charging queue Q besides B inside the circle. If not, the charging vehicle moves to the center node and starts charging node B to full capacity from the minimum charging expansion angle θ1.

[0098] If there are other nodes, calculate the priority of the queue to be charged among nodes other than B within the circle.

[0099] In this embodiment, the request threshold is set to δ1 = 350J, and the power threshold is set to δ2 = 250J.

[0100] In this embodiment, the value of R is 1m.

[0101] Step 3: Calculate the priority of the queue to be charged within the inner nodes of the circle (excluding B). The priority is calculated using the following formula:

[0102] F i =c1×fi +c2×s i (4)

[0103] Among them, F i Indicates the node n to be charged i The priority is given by c1 and c2, which are coefficients and satisfy c1+c2=1. In this embodiment, c1=0.4 and c2=0.6.

[0104] f i For node n to be charged i The initial allocation priority, s i The value is given by the following formula:

[0105] s i =d i / 2R (5)

[0106]

[0107] Where, d i For node n to be charged i Distance from the center node B, (x i ,y i ), (x B ,y B ) represent the nodes n to be charged. i The coordinates of the center node B.

[0108] After calculating the priority, construct a priority queue P by assigning the nodes within the radius of the circle to increasing priority.

[0109] Step 4: Determine the number of nodes in the priority queue, select the corresponding charging vehicle dwell point and charging method to charge the node, specifically:

[0110] Case 1: When the priority queue contains only one node A, the priority is determined by the distance d between node A and the center node B. AB The relationship between the charging radius R and the corresponding choice of the dwell point and charging method is as follows:

[0111] (1-1) If R <d AB ≤2R, such as Figure 3 As shown in (a), the charging vehicle's stopping point L is the midpoint of the line connecting node A and the central node B. First, the central node B is charged, with a charging expansion angle of θ1 and a charging center direction... Point in the direction of the center node B; after the center node B is fully charged, rotate the angle to align with the charging center direction. Point in the direction of node A to charge node A until the charge of node A is not less than the charging threshold δ3.

[0112] (1-2) If d AB≤R, such as Figure 3 As shown in (b), the charging vehicle's stopping point L is located at the center node B, the charging expansion angle is θ1, and the charging center direction is... Point in the direction of node A, and charge both nodes A and B simultaneously. Charge will end when the center node B is fully charged and the charge of node A is not less than the charging threshold δ3.

[0113] In this embodiment, the charging threshold δ3 is set to: δ3 = 500J.

[0114] Case 2: When the priority queue has more than one node, select the first two nodes A and C and the center node B, and calculate and compare the distance d between the three nodes. AB d AC d BC Let d be the longest distance among the three. max The corresponding selection of the dwelling point and charging method are as follows:

[0115] (2-1) If 2R <d max ≤4R, because B is located at the center of the circle with a radius of 2R, then d max Given the distance between points A and C, the charging vehicle cannot charge all three nodes from the same location. Only node A, which is earlier in the priority queue P, is retained, while node C, with lower priority, is ignored. Based on d... AB The relationship between the magnitude of R and the charging of nodes A and B is still handled in the manner described in Case 1 above.

[0116] (2-2) If R <d max ≤2R, and d max If it is unique, then the distance is d. max Does the two nodes include node B?

[0117] If included, the dwell point L is located at the midpoint of the line connecting the two nodes;

[0118] If not included, then the dwell point L is set at the second longest distance d′. max At the midpoint of the line connecting the two endpoints, if d AB With d BC Since both are the second longest distances, we choose d. AB As d′ max This ensures that the line connecting the dwelling point L has a center node B at both ends;

[0119] When d max If not unique, choose the longest distance including the center node B as d. max If the distance between the center node B and nodes A and C is d max Then the distance between nodes A and B is chosen as the longest distance, and the dwelling point L is located at d. max The midpoint of the line connecting the two endpoints;

[0120] The charging expansion angle is set to θ1, and the charging center direction is... First, point in the direction of the center node B to charge the center node B to full capacity; then rotate by π angle to make the charging center direction Point to the node at the other end of the connection and charge it until the power is not less than the charging threshold δ3;

[0121] Finally, determine if the distance from the dwell point L to the remaining uncharged nodes is greater than R. If it is, do not charge that node; otherwise, adjust the charging center direction. Point to this node and charge it until the charge level is no less than the charging threshold δ3.

[0122] Figure 4 (a) is the distance d between nodes B and C. max In Figure (b), if node A is within the charging radius, it can be charged; in Figure (c), if node A is outside the charging radius, it cannot be charged. max =d AC >d BC >d AB If the midpoint of the second longest line is chosen as the dwell point L, then node A in Figure (c) is located within the charging radius and can be charged.

[0123] (2-3) If d max ≤R, take the distance as d max Let the node with the lowest remaining energy among the two nodes be the dwell point L. Let L be the vertex, and the angle formed by the lines connecting the other two nodes to L be the edges. k Compare θ k The magnitude of θ1, if θ k If the angle is less than θ1, then let θ1 be the charging expansion angle; otherwise, let θ... k This refers to the charging expansion angle.

[0124] Using the bisector of the charging expansion angle as the charging center direction, charge the three nodes simultaneously until the central node B is fully charged, and the charge levels of nodes A and C are not less than the charging threshold δ3.

[0125] Figure 4 In (d), the distance between nodes B and C is d. max The dwell point L is at the center node B and θ k An example of a case where the value is less than θ1.

[0126] Step 5: After charging the node to the required level, set the node's M flag to 0 and remove it from the charging queue Q. The charging criteria for the node should meet are as follows:

[0127] After being charged, the energy of the central node B should satisfy the following formula:

[0128] P iB ×t iB +E′ re(iB) =E′ (7)

[0129] Among them, P iB The power that the central node B receives can be calculated using formula (1), t. iB E′ represents the charging time for the central node B. re(i) E' represents the remaining energy of the center node B at the start of charging, and E' represents the full charge value of the node.

[0130] After being charged, the energy of nodes other than the central node B should satisfy the following formula:

[0131] δ3≤P i ×t i +E′ re(i) ≤E′ (8)

[0132] Among them, P i Indicates the node n to be charged i The power to obtain energy, t i E′ represents the duration of charging the node. re(i) This represents the remaining energy of a node at the start of charging.

[0133] The relationship between the three thresholds is as follows:

[0134] δ2<δ1<δ3 (9)

[0135] Wherein, δ1 is the request threshold for issuing a charging request and building a queue to be charged, δ2 is the power threshold for assigning priority to the queue to be charged, and δ3 is the charging threshold for charging the remaining nodes except for the center node.

[0136] Step Six: Remove the recharged node. The charging vehicle remains at its current location. Add nodes that sent new charging requests during the charging process to the charging queue Q in the order they were sent. Use the head node of the charging queue Q as the new center node B. Calculate the priority of nodes within the radius and find the next resting point. Repeat the above operation until the charging queue is empty or the charging vehicle has insufficient energy to complete the next charge. The charging vehicle then returns to the base station to replenish its energy.

[0137] The energy consumption of a charging vehicle should satisfy the following formula:

[0138] E i +E r ≤E (10)

[0139] Among them, Ei E represents the energy consumed to charge a node. r E represents the energy consumed during operation, and E represents the energy limit of the charging vehicle. i E r The calculation method is as follows:

[0140]

[0141]

[0142] Where N represents the total number of nodes, P0 represents the power of energy transmitted by the charging vehicle during charging, and d LL+1 This represents the distance the charging vehicle travels from its current stop to the next stop. The total number of stops is u, where 0 stops represent a base station. e is the energy consumed per unit distance traveled, and d is the energy consumed per unit distance traveled. u0 This indicates the distance the charging vehicle travels from its last stop back to the base station.

[0143] In this embodiment of the invention, nodes are arranged into a charging queue according to the order in which they send charging requests. The first node in the charging queue is used as the center node, and a circle is drawn with a radius equal to twice the charging distance of the charging vehicle. Nodes in the charging queue are assigned priorities based on their remaining battery power, and the priority of nodes within the circle is calculated. The priority is related to the remaining battery power of the current node and the distance between the current node and the center node. A priority queue is constructed by increasing the priority of nodes. Based on the number of nodes in the priority queue, a corresponding charging vehicle dwell point and charging method are selected, allowing the charging vehicle to choose a location as the center node for directional charging of other nodes. In this embodiment, after selecting the first charging node, other nodes around that node are also considered, allowing for simultaneous charging of two or three nodes, reducing energy waste during movement. This embodiment makes directional charging more efficient, thereby maximizing the utilization of energy resources, improving the reliability and stability of the sensor network, and extending the lifespan of the wireless rechargeable sensor network.

[0144] Based on the above-described inventive concept, the present invention also provides a device for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, used to implement the aforementioned method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network. The device includes:

[0145] The directional charging calculation range determination module is used to construct a queue to be charged according to the time order in which nodes in the wireless rechargeable sensor network send charging requests, select a center, and determine the directional charging calculation range based on the selected center.

[0146] The priority queue construction module is used to calculate the priority of nodes other than the center node within the directional charging calculation range and construct a priority queue.

[0147] The charging decision module is used to make charging decisions based on the number of nodes within the directional charging calculation range, as follows:

[0148] If the directional charging calculation range only includes the center node, then the charging vehicle is moved to the center node for directional charging; otherwise, based on the number of nodes in the priority queue, the charging vehicle's stationing position and charging method are selected to perform directional charging on the node.

[0149] It is worth noting that this device embodiment corresponds to the above method embodiment. The implementation methods of the above method embodiments are all applicable to this device embodiment and can achieve the same or similar technical effects, so they will not be described in detail here.

[0150] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0151] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0152] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0153] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, characterized in that, include: The charging queue is constructed according to the time order in which nodes in the wireless rechargeable sensor network send charging requests, including: setting a request threshold δ1; when the node's power is lower than the request threshold δ1, sending a charging request and setting the charging flag M=0; and constructing the charging queue Q according to the time order in which nodes send charging requests. Select the center point and determine the directional charging calculation range based on the selected center point, including: selecting the first node B in the queue to be charged Q as the center point, and drawing a circle with a radius of twice the charging distance of the charging vehicle, 2R, as the directional charging calculation range, where R is the charging distance of the charging vehicle; If the directional charging calculation range only includes the center node, then the charging vehicle is moved to the center node for directional charging; otherwise, the priority of nodes other than the center node within the directional charging calculation range is calculated, and a priority queue is constructed, including: When the power of the first node in the charging queue Q is lower than the power threshold δ2, priority is assigned to the nodes in the charging queue in sequence; the priority is the ratio of the node's current remaining power to the request threshold δ1. Priority is calculated based on the node allocation priority and the distance between the node and the center node, as follows: ； in, For nodes priority, and Let be the coefficient, satisfying + =1, For nodes Allocation priority The calculation is as follows: ； ； in, For nodes Distance from the center node, and Representing nodes respectively The coordinates of the center node; Construct a priority queue P for nodes within the directional charging calculation range, excluding the center node, in ascending order of priority. Based on the number of nodes in the priority queue, the charging vehicle's stationing location and charging method are selected to perform targeted charging on the nodes.

2. The method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network according to claim 1, characterized in that, If the calculation range for directional charging only includes the center node, then the charging vehicle is moved to the center node for directional charging, including: Move the charging vehicle to the center node and charge it to full capacity with the minimum charging expansion angle θ1 as the center node.

3. The method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network according to claim 1, characterized in that, The step of selecting the charging vehicle's parking location and charging method based on the number of nodes in the priority queue, and performing targeted charging on the nodes, includes: If the priority queue P contains only one node A, then the distance d between nodes A and B is used as the basis for priority queue P. AB Based on the relationship between 2R and R, the mobile charging vehicle moves to the calculated dwell point L and uses the corresponding charging method to charge nodes A and B respectively; If the priority queue P has more than one node, then only the first two nodes A and C are selected, and the distances d between nodes A, B, and C are calculated and compared. AB d AC d BC Let the longest distance be d. max According to d max Based on the relationship between 4R, 2R, and R, the mobile charging vehicle moves to the calculated dwell point L and starts charging nodes A, B, and C using the corresponding charging methods. After fully charging the center node B, and charging all nodes except the center node B to a level not less than the charging threshold δ3, set the charging flag M of the nodes after this charging to 0, and remove them from the charging queue Q. Nodes that send new requests during the charging process are added to the charging queue Q in the order the requests arrive. The center of the circle is selected and the directional charging calculation range is calculated. A priority queue P for nodes within the directional charging calculation range is constructed. The charging vehicle's stationing location and charging method are selected in the above manner, and directional charging is performed on the nodes. The charging process continues until the charging queue is empty or the charging vehicle's energy is insufficient to complete the next charging cycle. The charging vehicle then returns to the base station to replenish its energy.

4. The method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network according to claim 3, characterized in that, If the priority queue P contains only one node A, then the distance d between nodes A and B is used to determine the priority. AB Given the relationship between 2R and R, the mobile charging vehicle travels to the calculated dwell point L and charges nodes A and B using the corresponding charging methods, including: like Then, the charging vehicle's stopping point L is selected as the midpoint of the line connecting node A and the center node B. Charging is first initiated at the center node B with a charging expansion angle θ1, and the charging center direction is... Point in the direction of the center node B; after the center node B is fully charged, rotate the angle to align with the charging center direction. Point in the direction of node A to charge node A until the charge of A is not less than the charging threshold δ3; like If the charging vehicle's parking point L is located at the center node B, then charging will be applied to both nodes A and B simultaneously with a charging expansion angle θ1, and the charging center direction will be [missing information]. Point in the direction of node A, and stop charging when the center node B is fully charged and the charge of node A is not less than the charging threshold δ3.

5. The method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network according to claim 3, characterized in that, If there is more than one node in the priority queue P, charging nodes A, B, and C includes: S1, if If so, only node A, which is at the beginning of the priority queue P, is retained, and node C is ignored. Nodes A and B are charged in such a way that there is only one node A in the priority queue P. S2, if , and d max If it is unique, then the distance is d. max Does the two nodes include the center node B? If included, then the dwell point L is selected at the midpoint of the line connecting the two nodes; If not included, then choose the dwell point L at the second longest distance. At the midpoint of the line connecting the two endpoints, if and If both are the second longest distances, then choose... As ; If d max If not unique, then choose the longest distance including the center node B as d. max If the distance between the center node B and nodes A and C is d max Then the distance between nodes A and B is chosen as the longest distance, and the dwelling point L is located at d. max The midpoint of the line connecting the two endpoints; The charging expansion angle is set to θ1, and the charging center direction is... First, point in the direction of the center node B to charge the center node B to full capacity; then rotate by π angle to make the charging center direction The node pointing to the other end of the connection is charged until the charge level is not less than the charging threshold δ3; Finally, determine if the distance from the dwell point L to the remaining uncharged node is greater than R. If it is, do not charge the remaining uncharged node; otherwise, set the charging center direction... Point to the remaining uncharged node and charge it until the charge level is not less than the charging threshold δ3; S3, if Let the distance be d. max Let the node with the lowest remaining energy among the two nodes be the dwell point L. Let L be the vertex, and the lines connecting the other two nodes to L be the edges. Let θ be the angle formed by these edges. k Compare θ k The magnitude of θ1, if θ k If the angle is less than θ1, then let θ1 be the charging expansion angle; otherwise, let θ... k For charging expansion angle; Using the bisector of the charging expansion angle as the charging center direction, charge the three nodes simultaneously until the central node B is fully charged, and the charge levels of nodes A and C are not less than the charging threshold δ3.

6. The method for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network according to claim 5, characterized in that, The request threshold δ1, the power threshold δ2, and the charging threshold δ3 satisfy the following: 。 7. A device for selecting the location of a directional charging vehicle in a wireless rechargeable sensor network, characterized in that, For implementing the method for selecting the directional charging vehicle's parking location in a wireless rechargeable sensor network according to any one of claims 1 to 6, the apparatus comprises: The directional charging calculation range determination module is used to construct a queue to be charged according to the time order in which nodes in the wireless rechargeable sensor network send charging requests, select a center, and determine the directional charging calculation range based on the selected center. The priority queue construction module is used to calculate the priority of nodes other than the center node within the directional charging calculation range and construct a priority queue. The charging decision module is used to make charging decisions based on the number of nodes within the directional charging calculation range, as follows: If the directional charging calculation range only includes the center node, then the charging vehicle is moved to the center node for directional charging; otherwise, based on the number of nodes in the priority queue, the charging vehicle's stationing position and charging method are selected to perform directional charging on the node.

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